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-V -
THE NERVOUS SYSTEM
AND ITS CONSTITUHNT NHURONES
DIlsraXKD FOR
THE USE OF PRACTfTIOXERS OF MEDICI XR AXD
OF STUDEXTS OF MEDICI XE AXD PSYCHOLOGY
I!V
LEWELLVS F. BARKER, M. B.. t..k.
ASSOCIATK I'ROI-KSSOK OI' AVAIOMV is
TIIK JriH.NS Ilol'KINs INIVKKSirv
AND ASSISTANT RKsrDKNT I-ATIK )|.. )( ;isT T(i
THK Johns HOPKINS KOSIITAI.
WITH TWO COLOR i:D I'l.ATES AND
SIX HUNDRED AND SEVENTY-SIX
ILLUSTRATIONS IN THE TEXT
NEW YORK
D. APPLETON AND COMPANY
l8c)c)
5=BM(Bto
CcirYHioHT, 1809,
By D. Al'l'LETDN ANI> COMPANY.
A
TO
WILLIAM OSLER, WILLIAM 11. WELCH
AND FHAXKLIX P. MALL
SUCCESSIVKI.V MV TKAi II KKS IN HAl.TlMORK
AM) TO MY FUIP:NI)
J II X H E W E T S X
OF HIVICKSIDK. (AI.IFtlKNIA
T II 1 S V I, U M K
IS GRATKI TI.I.V AM) KKSI'KCTKILLV DKDIi ATKD
l\' t
^'t
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^^
' \
PREFACE.
I\ 1S!)7 ii sorii'S of articles wiis begini in the New York
Medical .lournnl in which the attempt was made to present in
as simple and concise a form as possible the main facts con-
cerning the newer investigations into some phases of the anat-
omy and physiology of the nervous system. These articles
were continued at inter\als for two years, but the mass of ma-
terial proved to be too great, and neurological publications
increased so rapidly during this time that it soon became ob-
vious that any ade(|uate presentation of the subject must exceed
the limits which could be allotted to it in a medical journal.
The publication of a volume was accordingly decided upon,
the introductory chapters of which consist of the articles (re-
vised and brought up to date) which have appeared in the New
York Medical Journal. The body of the l)ook, however, deal-
ing with the groups of neurones Avhose axones constitute the
principal known tracts in the nervous system — centripetal, cen-
trifugal, and associative — is now published for the first time.
In the first part of the volume the newer conceptions of
the histology of the central and peripheral nervous organs are
reviewed. In the succeeding chapters the attempt has been
made to : pply the neurone conception — that is, the cell doc-
trine — as consistently as possible, in the explanation and de-
scription of the complex architectonics of the nervous system.
The term /icurouc is used throughout in the widest sense to
mean a ct'll b('JoiKji)i<! to iJif nervous si/sfc/ii with nil ih paiis, not
in the more restricted sense in which many authors employ it
and to which objection has in many quarters quite properly
been taken.
No apology is necessary for the rather profuse illustration
of the volume, for all experience teaches that, in morphological
studies especially, the form relations are more easily grasped
from the examination of good pictures and models than in any
V
VI
TIIK NKKVolS SVSTKM.
otlitT way, iiiul that one wcll-clKt-icn illiistrutioii with a satis-
factory l('i^(Mi(l is ol'trii of jrrcatcf value to the stiulciit than
many paj^t'S of lahorioiis and exact (ioscript i(»ii. Convineed of
this fact, especial pains have been taken in the seh'ction (tf the
cuts. Tlie hihiio^raphy has lieen extensively e'lplored in order
that the most instinctive pictures of the various anatomical
features extant in ori^n'nal articles mi<,flit he drawn upon, and
it i.j hoped that the hrin<fin^' to<,M'ther in one volnine of the
results of recent investifjators and skille(l artists of many lands
may he of service to ]ieiirolo;;ical students, es])ecially in Kn}^-
lish-s])eakin<j countries. I''<)r the oriifinal drawings and dia-
grams the autiior is dce[)ly indebted to Mr. Max Hroedel, .Mr.
H. Hecker, and .Mr. L. Sclunidt. The two litho^n-aphic ])lates
at the oml of the volunii' arc fmm Mr. Mroedel's hand, as are
also a large nund)er of the original diagrams of condiution
paths wliicli illustrate dilfercnt portions of Section \'I. 'i'li(>
series of drawings of transverse and horizontal sections through
the nu'dulla, ])ons, an<l midhraiu have been prepared by Mr. L.
.Schmidt from ex(|uisite serial sections kindly placed at the
writer's dis])osal by his friend Dr. .Injm llewctson. The other
original drawings are from preparations made in the anatomi-
cal laboratory of the .lohns Hopkins I'niversity.
Of the illustrations borrowed from origii\al articles, a few
have been taken, by kind })ermission, from American and Kng-
lish pul)li(^ations. The majority are, however, derived from
foreign source.s — French, (icrman, Italian, Hussian, Dutch.,
Spanish, and Swedish. In every case credit has been given to
the author of the original article containing the illustration,
and in a majority of instances the title of and exact reference
to the nu)nogra])li or journal whence the figure has been derived
have been ap])ende(l.
Kspecial thanks are due to the ])ublishers, Messrs. D. A])])le-
ton and ('onipany, for their liberality in defi-aying the expense
of the illustr.itions, es})ecially of those in which several colors
had to be em])loyed, and for the faithful reproduction of tlie
origimds by the most modern methods.
The nomenclature employed throughout the hook is almost
exclusively that of the UNA. A few exceptions have heen
made — notably the use of the terms dorsal and roitral instead
of posterior and uti/cn'or respectively, an obviously necessary
deviation, and one which has been urged for a long time by
PUKPACE.
Vll
prominent Anicrinvn lumtoniirtts. Kvcry ort'ort Ims been nmdo
to niiiintain u unifonn iiotiiciiclutiin' tliroii^'huut, uiui wlien^
(l('scri])ti()ns or illustrations have lu'on borrowed from otlier
Ixxiks or orij^inal articles, tlie author, fortlu; sake of uniformity,
lias taken the liberty of translatinjf the t<'r!ns ori<;inally em-
ployed into those of the new nomenclature. A feature of the
book, which has been responsible for the delay in publication
and for jjjreatly increased cost to the publishers, is the print inj!f
at the side of many of the cuts of the a(;tual names of the
objects illustrated, instead of reference letters and ti<.,'ures to
be explained in lejjends. The advantage to the reader is ob-
vious, and the aiitlior re<;rets that the nu'tliod, despite the time
and cost involved, has not l)een still more widely employed in
the makinjf of this book.
The sources of knowledge examined are sutliciently indicated
in the lunnerous footiu)ti's. There has been uo attempt, how-
ever, to exhaust the biblio<fraphy, and only the more important
references consulted have been citeti. The student, and espe-
cially the beginner, will doubtless be helped nu)re by a few
references to masters and to recognized authors and specnal
workers than by a full bi])liography of the various topics taken
lip. Care has l»een taken to verify the various nsfenmces at
the (litl'crent liliraries in Maltimore, aiul especially at the sur-
geon-genei'ars library in Washington. The writer has been so
frequently delayed by errors in liibliographic references in
neurological text-books and in medicral jourmds that he will be
])articularlv obliged to any reader who, detecting such errors in
the present volume, will inform him of them, that they may
be corrected.
It is an especial pleasure to acknowledge the lieip and stim-
ulus in neurological work which the writer has received from
various sources. The lectures of Professors Flecbsig, von Frey,
liis, ami Wundt in Leipsic in ISila ; the admirable text-l)ooks
of K. A. Schaefer, Foster and Sherrington, C. L. Dana, C K.
Mills,.!. Dejerine, W. R. (fowers, S. Kanion y Cajal, W. von
liechterew, \\ Marie, H. 01)ersteiner, A. van (lehuchten, A. von
Kolliker, ( . Wernicke, L. Kdinger, and ('.von Monakow; the
various publications of Apathy, Hastian, Heevor, Bethe, Bolk,
Berkley, Broadbeut, Dogiel, II. II. Donaldson, Ewing, Flatau,
Ferrier and Turner, Flecbsig, von Frey, (Joldscheider, (Jolgi,
Held, Ilenschen, Herrick, van Cieson, Ilughlings Jackson,
/i
f\
• • •
vm
TIIK NEUVors SYSTKM.
Horsley and Schiu'fer, .1. Loch, T.ugaro, Adolpli ^fcycr, },\o\\m^
Miiriiu'sco, .\i«8l, F. W. Mott, Patrick, Rctziiis, .1. S. Hisicii
KnsscU, Saiio, Shcrriii-rtoii, Starr, Kaiiion y Cajal, Tartufcri,
Tschcriiiak, W arriiifrtoii, and otlicrs, have been ospocially licl])-
fill. Tlic author is particiUarly indebted to Dr. Franklin I'.
Mall, Professor of Anatomy in the Johns Hopkins I'liiversity,
for aid and cncoura-rcnicnt in manifold ways in connection
with the i)ri'paration of the text and illustrations. Thilnks are
also due to Drs. Flexi'er, Thomas, Herkley, I'aton, Harrison,
and Hardeen, and to varioixs students in the Johns Hopkins
Medical School, especially to those who have undertaken ori^'-
iiud research. Dr. Frank H. Smith luis been kind enou^di to
thoroughly revise the text, and also to read the final proofs.
Miss Kleanore H. Watts has prepared the careful index of
authors, and has been most holpful in the prei)aration of the
manuscript and the legends for the figures. It is hoped that
by the use of two varieties of type (one referring to the pages,
the other to the nund)er8 of the figures), the value of the in-
dices will be increased.
Tni', .loUSS IIOI'KINS IldSI'ITAI,.
Baltimore, Mu., March IS, hS'J'J.
CONTENTS.
I'H n
SECTION I.
«
I
PAflK
1
TiiK ITisTORY OF Tin; Devioloi'mknt or TiiK Neuronk Concept .
ClIAI'. I. IxTKoKrcTOHV.
II. The sTi'DiEs or IIis, (ioL(ii, and Foiuoii .... 8
III. The STUDIES of Hamon v ("a.iai- and otheus with
(ioi.Ol's METHOD 20
IV. The vital sTAi.Nisd of the .nerve elements ... 31
V. The term "neurone" and the neurone conception . 39
VI. The in:Ai{iN(i of kesearches since 1H!U upon the valid-
ity OF THE NEURONE DOCTRINE 43
SECTION II.
The External Morpik/Loov of Neurones 66
VII. The external form of the cell hodv and of the
dendrites 66
VIII. The external form of the axis-cylinder processes or
VXONES 78
IX. Collaterals, side fihrils, and interneuronal sun-
stances 90
SECTION III.
The Internal Morpiiolooy of Neurones 101
X. Studies hy methods which reveal the interior of
neurones 101
XI, Varieties of nerve cells DisTi.VGUisnABLE by Nissl's
METHOD 11.')
XII. The nature of the tioroid masses or "stainable sub-
stance" OF Nissi 127
XIII. The (iRouND substance or "unstainable st-bstance" of
Nissi 135
XIV. Summary of our knowledoe reoardino the internal
STRUCTURE OF NEURONES 154
ix
m
mn
^^T^'^r^j.'si.'-Ji,-
TIIK NKUVOUS SYSTEM.
SECTION IV.
Tl.K niST.MH-.NKTU- KkI.ATIONS ..K THK NEUROXKS
(,,.,.. XV. Tmk okumn ..k tuk nkkvoks .vstkm .v tuk kmhkvo am.
TIIK KAKMKST 1I1S1«.1KXKT1(: STAIil.S
XVI. Tl.K l.KVKl,..l'.MK.NTAK lUsn.KV ..K TMK SIMNAK COKl. AM.
.MKDllXA OHlX.XIiATA . '
XVII Tl.K l.KVKU.l'MKNT OK TilK I-KHU-UKRAI. SKNS..KV NK.-
IU.NKS AND <.K THK SYMPATllKTIC NKUKOXKS .
XV I II OV Tl.K MKCl.AM.Al. KA.T..KS OK DKVKLOPMKNT ANl. OS
Till' IllMA.N .«<.1.V AS A SK.lMKSTKl. OIUIANISM .
PAQB
158
ir)8
170
17!)
li)3
SECTION V.
TUKNK.KONK AS Tl.K Un.T .N IMlVSlUl.UUl.AK ANO I>ATnoU.,a.- A,, ^^__
I'rdckssk
XIX. lN-.'.{t)llli TO.iY. . .„,.,
XX. ON Tl.K .,k.;knk.<atu.n an.. k..:..knk..at.on ok neurones . 2,^
XXI T..K l.{ ilTAISll.ITY OK NKUK(.N.:s . . •
XXII Tuk nkikonk as a knit ok NKUv.rs kinctk.n . . .
XXllI ON Tl.K 1..KK.T1..N OK ...NOrrTlON IN TllK NKIRONKS ANl.
' THE Tl..;oHV OK T1.K..{ DYNAMIC I'OI.AKITY
XXIV. T..K KK.,AT...NS ..K Tli-.l-.l.C TO NK.IV.KS KKNCTloNS IN
■IIIK NKIKONK . • •
XX\- ON Tl.K M.STOLOOICAL ALTKKATI..NS IN NKIKONKS DIE TO
Tl.K A.TION (.K I'OISONS. ANU A COMKAlilS(.N OK TllKSE ^
WITH TUK KKKKCTS OK TRAUMATISM
215
48
2r)7
275
. 282
SECTION VI.
On THE GUOI.-INO AND C..A.N.N.; TO0..r..KU OK NeURONKS .N A CoM-
!:LEX Nk.1V,..S SYV.KM ...KK T.IAT OK MaN AND lIlCHER
Animals.
Fur siimiiiary of tliis section see page 313.
\ i
LIST or ILLUSTKATIONS.
m
i
Plates I and H. S( iiKMAiir kki'KEskntation ok somi; ok tiik pkin-
III'AI. CONDli TION' TATIIS 1\ THE NKKVOIS SYSTEM . . Af I'lld of Ij0i)k
FKiCIlIS I'AdK
1. Multipolar giiiiHlii>ii I't'lls I'ldiii vent nil lioi-ii of OX . ... 4
2. (icrlacli's iR't\\oi-k G
U. ('oniicclioiis of dorsal and ventral roots of spinal c-ord accijrdint;
to a discarded tiieory 8
4. (Jolgi cell of Type I 11
5. Goljjri cell of Type II from cerebellum of rat 115
C. (iolgi <'ell of Type II from cerebrum of cat 14
7. Diffuse nerve network formerly supposed to be formed l>y the side
fibrils of cell Type 1 and the axoues of cell Type II . .10
y. Longitudinal sagittal section of dorsal funiculus of cat fifteen
days old 22
9. Transverse section of the spinal cord of a chick at the ninth day
of incubation 2'{
10. Schematic representation of dorsal funiculus cut longitudinally
jiarallel to entrance of dorsal roots 24
11. Cross section of the cervical spinal cord of a child two years old,
showing medulhited collaterals 25
12. lis. Cell intermediate in form between that of (iolgi cell Type I
and that of (iolgi cell Tyi)e II 27.29
14. Nerve fibres from a frog injected with methylene blue . . .33
15. Sensory nerve ending stained with methylene blue . . . X]
16. Left luilt of brain ganglion of Merei.i dicersirolor with the nerves
connected with it, seen from the dorsal surface . . .35
17. Scheme of lower motor neurone ....... 41
18. Cell from nucleus corporis trupozoidei of newboi'u cat, showing
axones . 48
19. Cells from nucleus corporis trapezoidci ^f an adult rabbit . . 48
20. Cell from the nucleus corporis trapezoidei of an adult rabbit,
showing axis cylinder 49
21. (ilomi ruins (dfactorius fi'oiu adult rabbit showing dendrites of
mitral cells and terminals (•■ nervi'olfactorii .... 50
23. A portion of the molecular zone of the cerebellum from an adult
rabbit showing terminal peridendritic axones .... 51
23. Motor-nerve spindle in longitudinal section of the right anterior
nervo .stem from the leech 53
xi
Xll
TIIK NERVOUS SYSTEM.
riOURB
24. Large (jluripnlar frnnglioii cell of the ventral paramedian field of
the abiiuiiiiiiiil cord of LumbricuH
85. The plexus of iieuro-fibrils in some retinal cells of the third right
eye of the leeeli
2G. A siibeiiidermal sen.«e cell, retinal cell from I'Keudo-brdiichellion
27. The distribution of the neuro-librils in the circular muscle fibre
of tile intestinal wall of /'oii/olidr/ld ....
28. Colossal ganglion cell ('i'y]ie Ci) from the leech
29. Three jjear-shaped ganglion cells of Type K, in longitudimd sec
tion, from the leech .
30. The course and connections of the conducting paths in a tran
verse section of the somite of the leech ....
31. Spinal ganglioTi of a newborn white mouse ....
33. Motor cell of ventral horn of spinal cord from the human fa'tus
thirty centimetres long
33. Pyramidal cell of cerebral cortex of mouse ....
34. Multipolar nerve cell from t lie cord of the embryo calf showing
varicosities of the dendrites
35. Neurones from the hippocampus of a puppy two days old
36. Unijiolar cell from a ganglion of Luiiidricufi ....
37. Photomicrograph of a normal pyramidal cell from the cerebral
cortex of a guinea-pig
38. Photomicrograj)h of a normal Purkinje cell from the human cere-
bellar cortex
39. Photomicrograi)h of the apical dendrite of a large pyramidal eel
of the cerebral cortex showing the arrangement of the latera
buds or gemraules
40. Neurone from the optic lobe of the embryo chick .
41. Golgi cell of Type II from the dorsal horn of the gray matter o
the spinal cord of tlie newborn mouse ....
42. Special cells ([loiyaxones) of molecular layer of cerel)ral cortex o
a dog one ilay old
48. Ramon y Cajal's cell from the suiierfuial layer of the cerebra
cortex of a fo'tal cat
44. Nerve elements from the retina of the ox ... .
45. Anax(>ne from the basket of a Purkinje cell of the cerebellar
cortex
46. Y-shaped division of sensory root fibres afti.'r entrance into spinal
cord in a six-months human embryo
47. End ramifications forming a basketwork about two Purkinje cells
of the cerebellar cortex
48. The relations in the olfactory glomeruli of the axones of the
olfactory neurones of the first order to the dendrites of the
mitral cells in birds
49. Nucleus of termination of the sensory part of the nervus trigemi-
nus of the cat
50. A much-branched fibre from the ojitic thalamus of a mouse .
PAOI
54
55
55
56
57
59
61
68
69
70
71
73
74
74
75
76
79
80
81
81
82
82
83
83
84
84
85
LIST OF ILLUSTUATIONS.
XIU
FIOrUB I'AdR
51. Three ciul arborizations of optic fibres from the optie lobe of an
embryo cliieit HO
52. The so-called "eliinbiiifj fibres" of tlie cerehellar cortex from the
brain of a child n month and a half old 87
53. Disc-shaped expansions on nerve fibrillie of the pig's snont and
their relation to certain of the epithelial (.'ells . . . . S7
54. Developing myelin sheaths of diflerent ages as seen through the
polarization mi'jroscope SH
55. Scheme showing the elements of the gray matter of the spina'
cord 91
56. Endings of collaterals from the dorsal fnniculi in the gray mutter
of the spinal cord of the newborn ral)bit 92
57. Side fibril of (Jolgi on the axone of a motor cell of tlie ventral
horn of the spinal cord 93
58. Pcrice'hdar networks believed by Held to be formed by tlie termi-
nals of uxones 95
59. Reproduction of a photograin of a perpendicular section through
the tip of the head of the gyrus centralis anterior of a healthy
adult man close to the falx 97
60. Reproduction of a (ih gram from a perpendicular cortical sec-
tion through the summit of the gyrus just in front of the
sulcus cruciatus of an adult dog close to the falx ... 98
61. Reproduction of a photogram of a perpendicular section through
the cerebral cortex of a mole, 1 mm. in front of the crucial
suture close to the falx 99
62. Ganglion cell from the electric lobe of the brain of the torjiedo . 103
63. Xerve cell from the region of the ventral column of gray matter
of the spinal cord of C'ddu.'i 105
64. Large motor ganglion cell from the ventral horn of spinal cord
of ox 109
65. Spinal ganglion cell from the ox showing clear spaces ( Vacuolen) 112
66. Spinal ganglion cell of liana Catesbiana 113
67. Nerve cell from olfactory bulb of rabbit 116
68. Nerve cell from dorsal nucleus of proximal portion of medulla of
rabbit 117
69. Motor nerve cell from ventral horn of gray matter of spinal cord
of rabbit 118
70. Large cell from Ammon's horn of rabbit 119
71. Nerve cell from ganglion on dorsal root of a cervical nerve of a
rabbit 110
72. Purkinje cell from the cerebellar cortex of the rabbit . . . 120
7o. Nerve cell from the spinal cord of the dog in the so-called
"chromophiie" condition 124
74. Motor nerve cell from the ventral horn of the gray matter of the
spinal cord of the dog showing tigroid bodies .... 125
7"). Cell of ventral horn of gray matter of human spinal cord . . 130
76. Nerve cell from Deiters' nucleus in the rabbit .... 131
m
xiv TIIK Ni;itVOL'« SYSTEM.
KUit'KE PAOIt
77. Nerve cell from the gray inatler (if the luiiil)ar ( onl (if fix . . 138
78. The eiKlocelluiur network within a i'lirkinje cell <ii' the eerebelliini
of Stri.r Jluvinicd 140
79. Cross sections of two axoiies frdni the nerviis trigeminus of
Pi'tromijZfin Jl'iri(ili/i,s 142
80. Ldiigitudimil and transverse section of nieilnllated nerve iihres
fnini the sciatic ." ve of !he frog showing (ine I'.ode of Han-
•^ vier and two of Lantermunn's segmentations .... 143
81. Axis cylinder in long and cross section from a s])inal ganglion in
th(^ himljar region of an adult ilog, showing iieunisomes and
axos|iongium 144
82. Axone hillock of a spinal ganglion cell of the dug .... 144
83. Cell from the ventral horn (if the lumbar curd of an adult rabbit
showing the axiine and .several dendrites 146
84. Centrosome and at traction sphere inside a spinal ganglidii ct^ll of
the frog 148
85. Nerve cell showing reticular investment 150
86. rericellular networks believed by Held to be formed by the ter-
ndtuds of axones 151
87. Networks about j)erikaryon and dendrites demonstrable liy the
method of Methe 153
88. Anterior portion of the body of a chick, the head tlistinctly dillcr-
enliated; seen from the surface 159
8i>. M('(lian section tlir(ii!:,di eml)ryo human brain at the end of the
first montl 160
90. Jlodel of (levelii|'ing human brain 161
91. ]\Iedian section o ftal luinnin brain during the third month . 162
92. Median sectidii thii'iigh adult human brain 162
93. Section through medidlary plate of rabbit showing germinal cell . 165
94. Section through neui'al tube which is beginning to close . . 165
95. Section thi'ough wall (if neural tube at a later stage . . . 166
06. Photomierograiih from a specimen through the neural tube of
A)nh/i/s/(>iiut 168
97. Section of spinal coi'd df a chick at the third day df incubation . 169
98. Section through half of neural tube showing the pear-shaped
neuroblasts 171
99. Transverse .section of the spinal cord (if a chick .... 173
100. Transverse .section through the upper tlioracic cord of the human
embryo 173
101. Commissural cell or heteromeric neiu'one from the spinal cord of
a l'riti/iiiriif< embryo 30 mm. long 174
103, 103. Transverse section through the medulla of the human em-
bryo showing N. liypoglossus, N. vagus, and tractus soli-
taries 174, 175
104. Section through i portion of the wall df the medulla df a human
embryo showing ncnroiilasts wandering from the rlidmboidal
lip tdward the middle line 176
LIST OF ILIA'STKATIONS.
XV
KKil'RE
105. tSeheiuo of one half of llie (;inl)r}oiii(: iiu'diillii at u later stage
106. Transverse section tlirougli one lialf of tlie niedtillu obloiigtita of
u hiiiiian criihryo at tlie eiglitli iiumtli .....
107. Longiliuliiial section of liie cerebral hemispheres of ^\fi!uri(.s
108. Reconstruction of human einhryo ut end of fourth week showing
development of sensory ganglia
109. Three stages of develoimient in the early history of the spinal
ganglia of the Innnan embryo
110. Transverse section of tlie emhryoiui; conl of the cldck .
111. I5ipoiar cell from the spinal ganglion of th<' pike . . . .
112. Bipolar ganglion cell from the ganglion spirale of the pig
113. Schematic re|)resenlation of the gradual transition nf tiie bipolar
cells of the s|)inal ganglia to the so-called unipolar type
114. Transformation of bipolar cells into tmipolar cells in the(iasserian
gangli(jn of the pig
115. Feltwork about spinal ganglion cells of thecal formed by division
of the axones of spinal ganglion cells of Type 11
116. Scheme of the reciprocal relations of the elements within the
spinal ganglion, according to Dogiel
117. Left auditory vesicle with the acustico-facial complex of a tuiman
endiryo at the fifth week
lly. (•phthalnn(! vesicle showing stalk and groove in stalk from a
human embryo of the fourth week, seen from below
110. Develo|iing eye of human embryo 10.3 mm. l.»ng . . . .
120. Composite diagrammatic transverse section of the head of a human
embryo to show the growing point in the nervous system, ami
the direction of the growth of the til)rc
121. Transver.se section through the anterior |)art of the trunk of an
embryo of Sci/lliinn
123. Photomicrograph of section through a nerve in the side of a
human tongue
123. Schematic representation of I lie nerve plexus of a heart of a
human embryo after His .Ir
124. Diagram showing successive positions of the diai)liragui during
the development of the human embryo
125. Schemes of transverse .sections of younger and iildcr Selachian
embryos to illustrate the development of the chief pn.ducts
of the middle terminal layer .
126. Fluman embryo fourteen to sixteen days (dd showing devcdoping
myotome
127. Human embryo at the end of the third week .showing developing
myotome and sclerotome
128. Scheme of bone and muscle segment
129. Trinik segment of human embryo with oni' pair of iicr'ves and the
rudiment of the musculature of (nie extremity at the sixth
week
130. Reconstruction of a young human embryo enlarged five times,
I'AOK
170
177
178
IHO
ISl
182
182
182
183
1H3
184
185
186
187
187
188
189
li)()
191
194
196
197
I i!
198
199
200
j^ttgajjOf^
XVI
THK NERVOUS SYSTEM.
I
FIOITRE PAOI
illustratiiif,' the positiDti of the M. rectus alxlominis and its
|)i)lyiiicric riaturi' 202
181. Fields on the extoriml surfiiee of the os iiiiioiiiimitum corresi)oii(l-
iiij; to tiie attfichiiieni of the viiriims iiuist'les .... 203
132. Outer surface of os itinnniinrtltim showing attachments of the
muscle masses derived from the myotomes innervated by the
twelfth to the nineteenth thoraco-lumbo-sacral nerves . . 204
133. Reconstructed form of pelvi of human fo'tus, illustrating skeletal
areas corn'sjiimding to the myotomes innervated by tlie 12th
to the nineteenth thoraco-lumho-sacral nerves . . , 205
134. Arrangement of the meta/onal dursal nerves for the Mm. glutaM 207
135. Arrangement of the nu;tazonal ventral nerves for the Mm.fl'^xores 207
130. Arrangement of the prozomil dorsal X. femoralis .... 208
137. Arrangement of the diazonal ventral N. < '-turatorius . . . 209
138. Arrangement of the ventral and dorsal prozonal, diazonal, and
metazonal nerves 210
139. Six transverse sections through a right upper arm showing the
relatioa of the (dark) ventroplanum to the (colorless) dorso-
planum, as well us the position of the fourth to the sixth
cervical sclerozones 211
140. Transverse section through the musculature of the shoulder and
che^t showing the limits between ventral and dorsal deriva-
tives of the myomeres 212
141. Transverse section through the proximal portion of the humerus . 213
142. Transverse section through the distal part of the humerus . . 213
143. Wallerian degeneration of nerve fibres after section . . . 224
144. Section through the cervical cord of a woman showing secondary
degenerations following compression of the cord at the level
of the second thoracic segment 226
145. Section through the lumbar cord of a woman showing secondary
degenerations following compression of the cord at the level
of the second thoracic segment 227
146. Section through human spinal cord in the ui)per thoracic region
showing marko'? atrojihyof right half of cord following ampu-
tation of right .'m 230
147. Transverse section through the medulla oblongata of a rabbit
showing degeneration from injury to facial nerve on the
right side 232
148. Cross section through the medulla oblongata of a rabbit showing
degeneration from injury to facial nerve on left side . . 233
149. Cells from the nuclei of the oculomotor nerves of the eat thir-
teen days after section of the root fibres of the nerve on one
side 235
150. Pour nerve cells from the nucleus nervi facialis of a rabbit fifteen
days after section of the nerve root 236
151. Ventral horn cells from the spinal cord of a case of multiple
neuritis 237
LIST (»!• ILLUSTIIATIONVS. xvii
KKll'RK PAdK
153. Nerve cell from cerebral cortex of dog showin;; ullerutioiis phicdy
ii; llif (Icndritcs tiiriit'il toward 11 llii'oiiiliuscd vessel , . 2158
153. Ijiirger pyruiiiidfd cflls fnuii tiie sccuiid lavcr of the cerebral cor-
tex siiowing advanced staf^es of degeneration rullowing ricin
poisoning of fourteen iioiirs' iliirat ion 239
154. Slronj; aiiieal (I'Midrilesof jiyi^aniidal cells I'nuii llie iniinan cere-
bral cortex 240
155. Frontal section tlirough the niesencejilialon siiowing vascnliir
supply 243
l.jd. Caryocinetic figures in nerve cells in brain of dog three days after
introduction of foreign body 24?
157. Scheuie <if t lie olfactory apparatus of inaninials .... 262
158. Section ihroiigh 'he optic lobe of the embryo (^hiek . . . 2(!S
15!). 100. Spinal cord of ,lw/y/(/(uv^s 2(i8, 2»)9
ltd. I'ortioii of spinal i'immI of new-born rabbit- stained by theciironie-
silver method 271
102. Schematic drawing to illustrate the course of the primitive lilirils
of the receptive and motor elements of the second antenna of
Carcimis Moenas 272
103. Section through ganglion on dorsal root of first thoracic nerve
of cat 276
164. Section through ganglion on dorsal root of first thoracic nerve of
cat after intermittent electrical stimulation during five hours 277
165. Camora-lucida drawing of occipital c<n'tex of pigeon to show rested
nerve cells 278
166. Camera-hicitla <lrawiiig of cortex of pigeon to show cliangcs in
cells indicating normal didly fatigue 278
167. Sections through the superior cervical ganglion of the rabbit
stained by Nissl's method 279
168. Two motor cells from lumbar ivgion of spinal cord of dog fixed
in sublimate and stained in toluidiii blue .... 280
109. Effects of arsenic upon the nerve cell 283
170. The effects of phosphorus poisoning upon the neurones . . 284
171. The effects of veratrin jioisoning upon the neurones . . . 285
172. Two spinal ganglion cells showing peripheral chromatolysis in
arsenical jioisouing 286
173. A nerve cell from a part of the spinal cord deprived of blood for
six hours througii ligature of the abdominal aorta . . . 388
174. Cells from the nuclei of ilie oculomotor nerves of the cat thirteen
days after section of tlie root fibres of the nerve on one side . 394
175. Cells from the human sjiinal cord in epidemic cerebro-spinal
meningitis 296
170. l-'our nerve cells from the nucleus nervi facialis of a rabbit fifteen
days after section of the nerve root ...... 297
177. Similarity of chang(>s produced in cell bodies of lower motor neu-
rones (1) by cutting the axonc and (2) by cutting the corre-
sponding dorsal roots 298
1
XVIIl
TIIK NKKVOUS SYSTKM.
'il
■^i4
KKH'IIK I'AdK
17M. lOITcc'ts of |)oisoiiiiip with iimloii-iiitril ;K)((
17!». I'llTccIs (if arliliciiil iiicr('ii."-c of body tfrii|iiialur(' .... 1501
1H(1. Iiccovcrv of vciitiiil lioni ci'll from clmiijiis |irotliici'(l by artificial
increase of liody t('in|ii'nittire IJOIJ
ISl. i'KTects of tetanus Idxiiie upon t lie lower motor iieiiroiics . . ;{(J4
IH'J. Moi'c advanceil staj^es of poisoninj; witli letaiius loxine , . iJ05
18;{. .Spiiuil fjanj^lioii cell showing inarked alterations following section
<d' the sciatic nerve ^IIO
1H4. Sjiinal ganglion cell forty days after section of corresponding
dorsal root .'ill
IHo. Cross section of the central and peripheral nervous system of a
man, illustrating the neural segment 323
lH(i. I'lcxus ccrvico-brachialis 324
1H7. i'lcxus lumhosacralis 32«
IHH. The ai'cas supi'lied by I lie cutaneous nerves of the head . . 327
IHi). Areas supplied by the cutaneous nerves of the upper extremity . 328
1!K). The areas of the skin supplied by the cutaneous nerves of the
lower extremity 329
191. Diagram of the position of the nipple in the sensory skin fields of
the fourth, third, and fifth thoraj.'ic spinal roots . . . 331
192. Cutaneous fields of dorsal roots of spinal nerves of monkey. Dor-
sal view 334
193. Cutaneous fields of dorsal I'oots of spinal nerves of monkey. \'cn-
tro-lateral view 335
194. Mode of distribution of the dorsal root filires of the lower ci'rvii'al
and thoracic nerves 33G
195. jNIode of distribution of the dorsal root fibres of the lower cervical
nerves and of the thoracic nerves 337
i9G. Jlode of distribution of the dorsal root fibres of the lumbar and
sacral nerves 340
197, 198. Referred pain in visceral disturbaiutes .... 342, 343
199. 200. Areas of pain sensation in visceral disease . . . 344. 345
201. Types of ana'sthesia 34(»
202, 20.3. Regiones cori)<)ris huniani 347, 348
204. .Spinal cord in connection above with the mediilia oblongata and
pons . 351
205. Portions of the pars cervicalis of the spinal cord with nerve roots 351
200. Scheme of periphei-al spinal sensory neunmes .... 352
207. Sagittal sectiiJii through seven sjiinal ganglia of (Miibryo mouse
10 mm. long, (.'ervical region 355
208. T'eripheral centripetal neurones of various animals . . . 357
209. Large spinal ganglion cell from a healthy man with connective-
tissue capsule 358
210. Several types of spinal ganglion c> lis 359
211. Nerve fibrils in the epithelial lining of the (rsophagus . . . 362
212. Nerve fibrils in the epithelium of a vertical section of the rabbit's
bladder 363
23(1.
2;i7.
238.
239.
240.
241.
242.
243.
244.
245.
LIST (»F II.I.I'STKATIONS.
XI. \
KKll'l
214.
215.
21«,
•JIH.
'ilU.
231.
323.
334.
32r).
336.
327.
33H.
22!).
3;i().
3;{i.
3:52.
233.
234.
235.
230.
237.
238.
23!».
240.
241.
243.
243.
244.
345.
'rcrriiiniitiiiii in \\w form i>r in-roil I'liil pliililcls (ni tlic <'iliuti'(l
ccllh tif llic t'nin's [mlaic ;{(>;{
Vcrliciil section tliidti^'li the ciinu'ii ;5(t4
'i'raiisvcrsc si'i'tiDii tiirou).'li till' skin nf the t ar of ii wliitc inuiise
lliri'o (lays ohl
317. Norvcs and ni'i'vi' cndin^^s ill tlio hiinmn cornea . . ;i(((i,
jMecliillated nerve lil)ro from the conjnnctiva of man
Nervi! endings in epitlu'liuin of frojj's palate
A (perpendicular section of the lower part, of the epidermis lie-
t\V(!en two papilla- which shows a lar^'e f,'rou|) of Merkel's
Taslzel/rn
A perpendicular section lliroufjjii tiie lower part of tiic epidernds
lietween two papilhe. from a fu'tus 3(» em. lonj;, to show the
development of liie nerve endinjis alioiil Merkei"s Tdufzvlltn .
(irandry's ternnnal nerve corpuscles from the duck's liili
Flat prc|iuration from the mucous mendiranc of the palate of a
duck showing nerve lUires and nerve endings .
Tactile discs from two Cirundry'.s corpuscles in connection with
the axis cylinders of the nerve fibrils connected with tiicin .
Nerve endiufjs about a large hair troni the dog ....
Krectile body of a hair of the rat
Nerves and nerve endings in the skin and hair lollicles.
N(U've endings in the form of tactilediscs beneath the glassy mem-
brane of the liaiis
Longitudinal view of tooth of (inliiiiK showing nerve terminals
Nerve endings in the liver
Periacinous plexus of nerve fibrils in the pancreas.
Nerve cells and nerve fibres in tlir villi and among the triaiids of
the iiitcstinuin teiiiie of the guinea-jiig
Nerve endings in the salivary glands ......
Section through the caput e|)iilidymidis of a young tomcat .
Nerv(! terminals .n t''ansver.se section of the tiibuli .seminiferi of
the rabbit ;{80
Nerv(\ endings in the mammary ghiiid 381
Two corpuscles containing nerve endings from t lie external con-
nective-tissue sheath of the dog's prostate .... 383
Free nerve endings in the basal inembrane at the junction of the
epidermis with the siiiicutaneous tissue ..... 383
Tactile corpuscle of Meissncr from a section through the skin of
the human toe .......... 384
Section through the skin of the too 385
IMcissner's corpuscle .......... 385
Tactile corinisde from the skin of the volar surface of the index
finger of a man twenty-five years olil 386
Peri[ilieral jwirt of conjunctiva palpebrarum of man . . . 387
Terminal nerve corpuscles in the eyelids of man .... 387
Semi-scheiratic section of the skin of the [uilp of the fingers in
3((4
367
368
:!6!)
369
369
370
371
373
373
373
375
376
376
377
378
379
380
380
m
<«>
XX
THE NKUVOUS SYSTKM.
Ill,
KIllUliB l-AIIK
order 1 1) (leniDiist rale tlic !ii|)nj;rii|iliy of L'ulllni's "icrmiiiiil
iicrvDiis niijiiris " ;IHH
240. HiiHiiii's iitMVf cmliiij^s ;iN|)
247. Tcnniiml nerve (•(ir|iiis('lc of IJiiniiii :i!i()
248. 'rraiisverse seel iiiii oT liiilliiii's teriiiiiml (■f>r|piiscle . . . . ."(id
24!t. ()l)li(|iie seel idii (if ii Icriiiiiijil iii'ivc i(ii|)u.sc|i' of liiillini . . :i!M
2.'5(l. A nerve lilire ilividiiij,' into si^veii seeuiidury liWres lo wliicli are
atlaclicil {\\v iiii/inir.s iii'rriN.r /I'niiiii/iii.riif Ifulliiii . . ;!!I2
2')!. Hnd hiillis slaineil liy llie iiielliylene-liliie inelliod .... '.W.i
232. 'I'erriiiiial ciiriuiscle lioiti iln' lilire "f tlie iinijiiiKl i\M ludlii . . ;}!);{
2r).'{. Ilerl)sl's ec)|-piisi les ;{!)4
254. ('()r|)iisel(< of Pacini of the niesoiitery of an adnlt cat . . . ;()(.'»
'■i'hK Oolj^i-Mazzoni corpuscles ;{!)7
25(5. (lenital nerve coi'|)nscles fi'oin file iniicoiis mendirane of the cli-
toris of tiie ral.iiit :i!»H
257. (iunital nerve corpuscles from tlie nuic<jus niendjrane of the f^lans
penisof (he ralil)it :»)!»
258. Cross section of ;,'enital nerve corpuscle fi'oni the clitoris of the
rahbil ;!!»0
25!), 2(1(). (ienital nerve ('or|Miscles from human jjlans penis . . 400. 401
2()1. I'lnd i)idh from f,'lans penis of a white mouse 402
2t>2. A brunch of one of the anterior nerve filii'cs of the cornea . . 40;{
26;J. ."Musculo-tendiiious nerve ending' of (iol;;:! ..... 404
2fi4. Tendinous expansion of oi'e of the muscles of man . . . 40G
205. A terminal niuseulo-tendinous organ in which a terminal nei've
])la(pi(> occupies nearly the length of the tendon . . . 407
2C0. Human tendo calcani'us (Achillis) 408
2(57. Tendinous expansion of one of the motor muscles of the eye of
an ox 40!)
268. A .sensory nerve ending froin exocardium of ujipei' half of left
atrium of the heart of the gi-ay rat 410
2(5i). Nerve endings in the lung of the frog 411
270. S(^nsory nerve cndiniTs in the ciliary body of birds. . . . 412
271. Nerve endings in ciliary body demonstrated by the method of
Golgi 41!}
272. Muscular spindle from .Ui/fi.rns ((rcll<ni<iriiin 414
273. Middle third of a terminal pla(|ue in the muscle spindle of an
adult cat 416
274. A striped muscle fibre in a lium.in muscle spiinlle with ti-rminai-
niiiis a Jlt'iirs 417
275. Muscle spindle from intrinsic plantar muscles of a dog . . . 418
276. Surface vi(>\v of cardiac muscle cells with nerve endings . . 41!)
277. intermuscular end arborization from the left wall of tlu^ trachea
of the (log 420
278. Ijongitudiiiid section of involuntary muscle showing nerve end-
ings 420
27!). Nerve ending on the vas afferens in the cortex of the kidney . 421
''lif
IJST OF ILIA'STUATIONS. xxi
KIOfKB I'AliK
2H0. Fiftures illust nit ing flic dorsal fiiniculi in tin- cervical, tlidriicic,
ami liiniliiir rc;,'i()iis 111' t he >|iiiial conl ..... 4'M
'J81. L'p|)cr half of liiiiiliar cnlargcincni of u ficliis li.") cm. loiif; . . 4!Jb
SH'J. t'ross scftion through the sjiimil t-ord at the level of t lie third liiiii-
liar iiervi) 421)
J8;{-!i90. Tliu lilirc sysfoiii.s in the spinal cord of the f(ctus . . 4;il-4U4
291. Tho nerve tracts in u case of lnnil)ar tabes (Trepinski) . . . 4U0
2i)2. .Secondary dee;cnciiil inns in the spinal cord lifter exiierimental sec-
tion id' dorsal roots 440
'jyJJ. Transverse section of the hnman spinal cord showing sccondai'V
degenerations following isolated loion of the sixth thoracii;
spinal nerve .......... 445
294. Seliomc of the course and tcrndnation of the fibres of the dorsal
roots 448
295. Secondary degeiuTalion in the dorsal funiculi Itclow a transverse
lesion due to compression of the cord 449
296. lioiigitudinal section in an almijsl sagittal direction at the level
of tlu! eighth thoracic nerve showing degenerated lllu'cs in
ihe dorsal funiculi after transverse lesion .... 451
397. Descending degeneration below a transverse lesion at the level of
the seventh thoracic segment 454
298. Descending degenerations below a lesion (compression) of the
spinal cord at- the level of the eighth cervical nerve . . 455
299. Sagittal longitudinal section at the level of the fifth sacrtil nerve
from a ease of compression of the cord at the level of
r. viii 450
300. Cross section tiirough the spinal cord of a rabbit eleven days after
compression of the aorta for one hour 460
301. Transverse section through the medulla oblongata in the region
of the decussatio leinniscornm ....... 402
302. Cross section through the medulla oblongata at the level of tlu^
lower half of the nucleus olivaris inferior .... 402
303. pjutrnnce of tlie fil)res of the dorsal roots into the dorsal funiculus
of the spinal cord of an embryo calf 467
304. Scheme indicating tlio course followed by the central axones of
the peripheral spinal centripetal neurones in the dorsal funic-
uli of the spinal cord 469
305. Cross section through the spinal cord of a newborn babe, to show
the collaterals 471
306. Scheme of the structure of the spinal cord 472
3(t7. The developing cerebral norvos 478
308. Transverse section through medulla oblongata of newborn child
at level of decussatio lemniscorum 479
309. Transverse section of medulla oblongata of newborn child passing
through the nucleus olivaris inferior 479
310. Transverse section of the medulla oblongata and cerebellum of
new-born child showing nucleus dentatus .... 480
t
4
'■^n
XXII
TIIK NKIIVOUS SYS'I'KM.
KIOI'HK VM*
lilt. 'rnuiMVorsc sect ion (liroii^h tin' iih-iIiiIIk i>l)Ii)iipilii iinil (')'r(>lu>IIuiii
of iii'wiioni chilli ; ic;;ioiM>r coclili'iir iiiicitM , . . . IHl
312. TratiHV(>r.si>s(M'lii>ii liiroii^'ii tlir i'iti'IicIIiiiii aiiij iiiciluliii ohjori^utit
lit tlif jiiiicl ion r>r the liiltt'i' will) the pons .... 4H2
31S. 'rriinsvi-rst! sfciior, tliroiijjli lln' poiijs ant! corchclluni at tin- level
of the in'iiK'ipal motor nntleus (if the Irip'iiiiiml nerve . 4H',\
UM. Transverse section throiij^h the islhinuH rhoinbuiicopiiali oC new-
born lialie 184
315. 'I'ransverse section at the level of the collicr.lns inferior of cor-
pora i|iiailrip inina of newliorn lialie 4H.'5
KHi. Transverse sect ion through inesencephalon of newliorn lialie: level
of superior i-olliculiis 4Htt
HIT. Transverse section thmiiyh superior collicnli ami cereliral pe-
(Inncle of newliorn halie |H7
31H, 310. Horizontal section thmui^h meilulla, |ions, and niiillirain
of newliorn lialie; level of nucleus iiervi aliiliicentis , 4HM, 4S9
ti^O. nori/<intal section through rhoinliencephalon and mesencephalon
of newborn babe; level of fastiiculus lonf,'itnilinalis me-
dialis 400
321. llori/ontal section through medulla, pons, and midbrain of new-
born babe; level of the nucleus nervi oculomolorii and nucleus
norvi trochlearis
322. IIori/<intal section through the inedidla. pons, and midbrain of
newborn babe; level of deoussatio brachii conjunclivi .
321). Hori/ontal section Ihrouj^h meilulla. pons, and midb-ain of ni'W-
born babe ; level of corpus trape/oideui.i
324. Hori/ontal section thron;;li medulla, pons, and midbiain of new-
born babe; level of nucleus olivaris and nucleus ruber .
325. Diajjram of nuclei of cerebral nerves
32ri. I']ndin^'s of axones of N. vagus and N. glossopharynjj;ons
327. Tractus solitarins of six-day-old cat
328. Horizontal section through medulla, pons, and midbrain of new-
born babe; level of nucleus nervi abdueentis ....
320. Cro.ss section thi'oiigh rhombencephalon of four-day-old mouse;
lovol of nncleus N'. hypoglossi
330. Synipnthicus and X. vagus of human e"'bryo
331. Left auilifory vesicle with iiciistico-fucial complex : human embryo,
fifth week .500
332. Sclionie of peripheral termination of X, vestibuli .... .501
333. Isolated impregnated inter-epithelial entl arborization from the
nnu^ula acnstica sacculi 502
334. iintoral sagittal section through the X. vestibuli of fictal mouse . 503
335. Diagram of nuclei of cochhwir and vestibuliir nerves . . ,506
33(5. Transverse section of medulla oblongata and cerebellum of new-
born babe showing nucleus dtnit.-itus ,508
33T. Transverse section thn • ^h iiu'duUa oblong.-itii at tlu' junction of
tlr^ latter with the pouh 510
401
402
403
494
495
406
406
497
498
490
\\
LIST (»F II<IJ STUATIONS.
will
KIlll'IIK I'AIIK
'MH. I'cricclliiliir oiulings of colliiieniln fi«>m axoiics of (lie iiorvi vcsti-
liiili ill llic iiiu'lciis iifi-vi M'.'liliiili l"t('ruli> .... 't\'.i
'MO. (iiin^lioti Ki'iiii'uli of iifwiMirn inoiisi' .'ti:)
;(-l(>. N't'iitral view of ccrclinim with |porlioii of spinal ccinl . . . "il.")
;t4t. 'rruiisvcrsc .srctioii llin)ii;,'li the |ioii.s and ct'i-i'lii'lliiiii ut ilii-
li>V(>l of till) |iriii('i|)iil motor nucleus of llir tri^i-miiml
nerve "ilO
342. Sclieine of motor ami .leiisury iH'iiroin's, ihc iixoiies of wliicli enter
into the formation of \. IriKemiiuis 517
348. liiiteral !<a;;ittal section throu;;h pons ami cereliellnm of I'o'lal
mouse .sliowiny sensory portion of nervus tri;;eminiis . . ."il^j
344. Traiisvorse section throii;;h medulla obloiigutu and cereliellum of
newhorn child III level of veiil nil cocdilear iiui'lens . . . "dO
■M'). Same as Kiy. II'JI .V20
340. Transverse section tlinni^'h tractiis spinalis X. trip-mini of new-
liorn rabbit 521
347. Tastt-I)ud 520
348. Taste-buds 527
340. l'eri|)lieral and central coiidni'lion |iiilli-< connected with orpinon
Justus 538
35(1. Seheine of c()urse of nerve impulses in lilfactoiy apparatus of
mammals .529
351. Glomerulus olfactoriiis from a young cat 530
352. Nasal mucous membrane innervated by N. oll'acioiii . . . 531
353. Transverse section tliroii<;li retina of man 535
354. Sflieiiie of structure of retina 5;<fl
355. Scheme of visual ccMiductioii path 537
;)5«. Epitiiclial cells of t lie retina 538
35T. Section through rot ilia of an udull dog 538
358. Nerve cells of retina of an ox .")39
35!l. Perpendicular section through retina of an ox .... 540
3G0. Structure of retina and visual lobe of A7('(/o/i(' .... .548
361. Labyrintlius inembranaceus in human embryo at the fiflli month. 544
362. Section through cochlear region of labyrintlius osseus and ineiii-
branaeens of guinea-] lig 545
303. Hijiolar cells from ganglion spirale cochlea" of young mouse . . 546
304. Spiral organ of Corti 547
305. Same as Fig. 312 i4H
366. Same as Fig. 310 54!)
367. Diagriim of nuclei X. cochlea' and <'orp IS trapezoideum . . 5.50
3()S. Kntrancc of X. cochleiiMiito central nevvous system . . . 551
30!t. Termination of axones of X'^. cochlea' 552
370. Sagittal section showing entrance of X. cochlea' in fo'lal mouse . 553
371. ^lode of termination of axones of X. cochleie in newliorn cat . 554
372. Floor of fourth ventricle 557
373. Transverse section at the junction of the medulla spinalis with
the medulla oblongata 558
•*™-
XXIV
TIIK NEltVolS SYSTEM.
KKU'ltK
il74. Transverse section llirdiiirh iiu'dullii dhldiipilii n\ llii- level of de-
ciissatid pynirnidimi
y?."). Transverse section tlii'oujjii niediillii oliiongiilii showing nervns
hypoglossi.s. ..........
.'STfi. Transverse seel ion of inednllii ol>lonj,'atit at. level of caudal I'nd <it'
nu(deus olivai'is inferior
U7T. Transverse section of medulla ol)lonj;ala, level of the middle ti(
the ucleus olivaris inferior .......
[ilK Transverse section through medulla oiilon^^ata at the level of the
deeussalio leniniscoiuin
.170. i-'ilira' arcmdu' .
;{SI». Same us I'^i;;'. ;i-,'^»
;W1. Same as Kij;. :!','4
iW'2. Course of axones from nuclei of dorsal funiculi to lemniscus and
corpus resliforme .........
;58;5. Transverse section of medulla showing degenei'ation followingdu-
sti'iH'lion of nucleus funiculi gracilis .....
884. Transversi^ section of nu'duUa showing dcgeiieialion following de-
stnu'tiou of nucleus funiculi gracilis at a higher level .
385. Frontal seetion through rhoud>encephalon of monkey after de-
struction of nucleus funiculi cuueati and of corpus resti-
forme .
380. Ti'ansverst' sections through posterior half of pons and through
midbrain
387. Cross sections thnuigh hum.in spinal cord
388. Nerve cell from nucleus dorsalis, hunuin emliryo ....
389. Frontal section at junction of pars thoraealis and pars lunibalis
of spinal cord
3f)0. Transverse section through ]>ars eerviealis of llu' cord .
3itl. Transverse seetion through u|)per third of medulla oblongata of
huinan fu'tiis
3!>2. Frontal section of medulla oiilongata and cerebellum of seven
months' f(et us; level of nucleus vestil)uli ....
3!(;i. Frontal section of nu'dulla oblongata and cereliellum of seven
months' fo'tus at the level of inicleus dentatus
3!)-l. Frontal section through rhombeiu'cphalon of monkey after de-
struction of niu'kus funiculi cinieati and corpus resliforme .
3i)r). Transverse section of spin.il cord at the level of fourth, cervical
segment !o show degeneration of (iowers" tract
3!)6. Scheme of c(-ursp of I'lbre:-, of the two principal tracts from spinal
cord to cerebellum
307. Degeneration of (iowers' tract above nu'dul la oblongata
398. Ascending (^.egcneration of (towers' tract
3)(!(. Central sensory conduction ]ialhs in the spiiuil cord
400. 'i'automeric, beteroineric. and hecaferomeric neurones in pars
lumbalis of human spinal c(U'd
401. Transverse section through |iosterior part of pons .
r>,-)9
ntio
r>()i
rm
."•)(;(>
;-)(i7
571
572
573
574
578
582
583
584
585
596
588
589
591
593
595
596
()05
607
CIO
424
434.
LIST (»F ILI.rsTUA'l'loNS.
x\v
KIOrnE TAfiK
AU2. Soctioii tlironf,'!) iiii'diillii (il)l(iii(,'iitii iit Icvi'l of N. vtijjiis ninl \.
liypiif;li)ssiis (ilv;
<((•;(. Sffliciii llii'(iiij,'li Micdulla oli|<iiijiiil;i ; level <>1' root nl' N. f,'l(isM.-
|iliiiryiif^('iis (»i;J
404. Cross ^itM•li()n tlirinif;li i^llmiiis rliiiiiilieii(e|)iiiili .... ^\\^^
405. Simic as Fij;. :m 01(5
400. Sn^ittiil section of ineiliillii, |ioiis, iiikI inidln'iiin in eliilil iii;eil
tlirei- iiioiillis 017
407. Same as I''i;;. IJi.'.') O'J'2
40H. Set'lioii tliroiij;li nucleus alii' ciiicreii' in <'liil(l six weeks old . . 02!J
40!). Same as Kij;-. ;!2!t O'.M
410. Transverse .sccl ion oT medulla tliroui,di nucleus comniissuralis . O'Jo
411. Same as Kifj. ;{;tr> 02H
412. Section through rhoinlicnet'|ihalon helow the fjcnu internum
radicis N. facialis (U!)
41i{. Frontal section through jions, sliowing Dcitcrs" unil Hechterew's
nuclei in newliorn mouse OHO
414. Same as Fig. ;{ir> 0;il
415. Same as Fig. :{2;5 0;5;5
416. Same as Fig. ;!12 6;J4
417. Transverse .section tlirough rliond>en(.'ephalon of mouse showing
Deiters' nucleus fi;{5
418. Obli(iue section through brain stciTi ol' newitorn cat showing imth
from l>eiLcrs' nucleus to the cord GliO
41!). Transverse section through Deiters' nucleus in the mouse . . {u]S
420. Horizontal section thr-mgh medulla, pons, and midlii'ain of new-
liorn babe, level of decussatio brachii conjunct ivi and nucleus
reticularis tegmenti 6;{!)
421. Same as Fig. ;i4(> 043
422. Transver.se section through brain stem of young rat showing de-
cussation from t lie nuclei N. trigemini 045
423. Horizontal section of cerebellum showing marginal thickenings
of the lingula 048
424. Transverse .section through ceri'bcllum and nu'dulla of human
endiryo showing nucleus (l.'iitat us 04!)
42.'). Same as Fig. ;il() 050
420. Same as Fig. ;il4 051
427. Same as Fig. tilH 0.53
428. .Stilling's large and sMuill "scissors" of the brain .... 053
42!). Same as Fig. liUi «54
430. Same as Fig. 420 056
431. Same as i'Mg. 404 658
433. Same as Fig. 3H(i 000
433. Frontal s(>ction through corcibellum and pons of fo'tal mouse
showing N. trigeminus (i03
434. Lateral sagittal section through jions and cerebellum of fict.il
mouse showing sensory part of X. trigemiinis . . . . 003
&
XXVI
THE NEItVOUS SYSTEM.
I I
FIOURK PAOB
43.'). Transverse section throuj^li middle of sii[)erior colliculus . . (iti!)
436. Frontal section tiirouf^li liunian brain stem showinii; I'^orel's Fc/d
yy and till) I'orjms Lnjsi <)70
437. Frontal section tlirongli liypothalaniic rcfjion, luinniii lirain . 073
438. Frontal section through brain stem showinj^ Forel's Frld //, and
//., 673
439. Frontal se.Mon through brain stt-in of man siiowing corpus
Luysi ()7()
440. Frontal section ilu'ou^h decussalii) Ijrachii conjunctivi . . . OhJl
441. Frontal section through normal human brain at level of corpus
goniculatum mediale 083
443. Frontal section through human brain at level of nucleus hypo-
thalaniicHis . 083
443. Frontal section through human Inain at level of ansa lenticulu-
ris 084
444. Frontal section through human brain at level of thalamus . . 685
445. Isthmus rhonibencephali in prolile ....... 087
440. Scheme of tlbi'es in superior colliculus ...... 688
447. Same as Fig. 37H 089
448. Same as Fig. 314 Oi)0
449. Same as Fig. 333 091
450. Sagittal section of babe's brain showing capsula interna . . 093
451. Same as preceding 093
453. Same as !''ig. 310 095
453. Same as Fig. 333 096
454. Schemes of course of lemniscus medialis ..... 098
455. Scheme of degeneration in a case of lioesel and Flechsig . . 703
456. Scheme of central paths 706
457. Degeneration after destruction of dorsal funiculi .... 710
458. Cortical area of termination of lemniscus filires in the cat . . 713
459. Same as l''ig. 400 719
400. Sagittal section through brain of In'tai mouse siiowing fa.sciculus
longitudinalis 730
461. Same as Fig. 333 733
403. Same as Fig. 334 733
403. Same as Fig. 317 734
404. Same as Fig 409 738
405. Same as Fig. 413 739
460. .Sagittal section through human brain 735
467. Frontal section tlirougii human iu'ain 736
4()M. ilori/ontal section through human brain 737
409. 470. Scheme of general soma'sthctic paths .... 743, 744
471. Scheme of neurones superimposed in general soma'sthetic paths , 745
473. Scheme of relations of anterior and posterior olfactory lobes . 750
473. iJasal surface of human fu'tus. fifth month 751
474. Basal surface of lii'ain of man fiirty-thrc(> years old . . . 753
475. lihinecephalon of a man fcir'ty-lhi'ee years old .... 753
LIST OF ILIiUSTKATlONS.
xxvii
FiorRK I
47(5. Jjowcr |iiii't of {^yriis liip|»i('iiiiii)iis .......
477. Inferior untprior extremity of f^ynis liipiiocmiipiis .
478. Frontal section of biill)iis olfactoriiis of yoiitig ral)l)il .
479. Transverse section of liiinuin 1mi11)iis oifactorius ....
480. Horizontal section tlirouf,'h l)nll)iis and tractus olfactoriiis of man
4H1. Mitral cells from nionse twenty-fonr days old ....
4H2. !{nli)iis olfactoriiis of mouse twenty-four days old ....
48;J. Same as Fij,'. liol . .
484. IJulhiis et lobus olfactoriiis of rai)l)it in liorizoiit a! section
48.'). Three olfactory ^^raniiles from a cat
48(5. Ventral |iarl of frontal section of ralihit's brain showinj; basal
f,'inif,dion
487. Islands of pyramidal cells in tuljcrculiun olfactoriuin of rabbit .
488. One of C'allcja's islands in the olfactory tubercle of the rabbit
48!i. Section through base of lirain and hippocam])us ....
490. Cells from nucleus corporis maiiimillaris of a child
' Sagittal section tlirougii corpus niammillare of newborn mouse .
: , Frontal section through iiiicleiis ruber and nucleus N. oculo-
motorii of fcctal nioiisi'
4S)3. Oblique section through brain stem of cat four days old showing
formatio reticularis
494. Oblique section through brain stem of cat four days old showing
the decussatione.s tegmenti
495. Oblique section through brain stem of cat eleven days old showing
origin of (ilires of fasciculus longitiidiiialis nicdialis
496. Transverse section tiirough tela chorioidea ventrieuli tertii .
497. Sagittal section of brain of a rabbit with bands of fibres in three
planes
498. Golgi preparation from peduncular region of mouse
499. Diagram of Meynert's bundle
.'iOO. Hori/ontal section of i)rain of C^/ypr/MHs crt/7»'o ....
501, 502. Principal neurone systems of olfactory conduction path. 779,
50:i. Nerve cells from the retina of the chick
504. Brains illustrating atrophy following removal of eye in newborn
rabbit
505. Hemoval of left half of chiasma opticiim with the commissura
inferior (Juddeni ill the ralibit .......
506. Chiasma o|)ticum and tractus opticus ill liuiuan brain .
507. Scheme showing Ileiischen's investigations on relations of bundles
in optic nerve, etc
508. Absence of optic chiasm
509. A ])()rtion of the right cereiiral hemisphere to illustrate the basis
cereliri ...........
510. Frontal sections through corpus geniciilatuni iaterale of dog
511. Horizontal section through cerebral peduncle and hypothalamus.
512. Corpus geiiiculatiim laleviile of newborn cat .....
513. I'ulvinar of mouse five davs old
■A<1K
753
754
756
757
758
759
760
761
762
763
764
765
766
767
769
770
771
773
776
777
777
778
780
785
787
788
789
794
795
797
79!)
801
802
803
i.i
11' '1
> '
I
XXVIU
TIIK NKRVOUS KV.STHM.
'
]\
Ml
KKir
514.
515.
51(i.
517.
518.
519.
m).
5'Jl.
5:.>;j.
5'24.
5:^5.
526.
527.
528,
52l».
5;iO.
531.
532.
5:J3.
534.
535.
53(i.
537.
538.
530.
540.
541.
542.
543.
544.
545.
54().
547.
548.
549.
TriinsviTsc scctidii (if iioriiijil liiitnan optic chiiisiii .
Sfctiuii (if brjiiii of cliild tlircc inoiillis old sliowiiij; optic ciiiasiii .
Uniiii of riiljliit aflci' I'cmoval of one eye and scmmhiicc of tracttis
opticus
Frontal section tliron;;!! liinnan liypotlialainu-- . . . .
Frontal sc^ction tliroiif;li coiliculus su[i('rior of the raliljit
Transverse .section through colliciilns .superior of rabbit
Fi'ontal section tliroiii,'ii occipital lohc ......
l''rontal section of liunian l)rain illustrating' visual conduction path
Frontal section of huuuiii brain iliustratinf; occipito-lhalaniic
radiation
Frontal section of iuniian brain illuslratinf,'occi|iito-tlialaniic radi-
ation, etc
Posterior |iart of left cercliral heniispliere, medial surface
Horizontal section from brain of ciiild in second week of life
Xorinal and defjencrated corfius genicuintuin lateralo .
Frontal section through nucleus iialicnula' and tludamus of new-
born mouse
Section through cortex of the gyrus occipitalis superior
Scheme of visual conduct ion paths .
Scheme of hypotlu'tical decussation of axoucs from coi'|)Us geni(;u-
latum laterale to lobus occipitalis
Optic central paths illusti-ating von Monakow's view of represen-
tation of the ri'tiua in the cortex
Sciienie of optic [)aths illustrating cortical and subcoi-tical hemi-
anopsia
\'isual conduction jiath
Visual conduction paths
Section of brain stem of newborn cat illustrating the separation
of the fasciculus longitudinalis from the fibre system from
the colliculus superior to the ventro-hiteral funiculi and the
relation of the lateral lemniscus to the colliculus inferior
'I'ransverse section of medulla ol)longata showing cochlear nuclei.
Same as Fig. 313
Same as Fig. 323
Same as Fig. 314
Same as Fig. 440
Nucleus nervi cochlea' vcntralis of newborn cat . . . .
Nuclei termimiles of nervns cochlea' of four-day-old rabliit .
Cross section of pons showing imcleus nervi cochlea' vcntralis
'i'ransveise section through nucleus olivaris superior
Terminals of axones in the nucleus corporis trapezoidei.
("ell from nucleus corporis trape/oidei of newborn cat .
Cell from niu'leus corporis trapezoidei of adult ral)l)it .
Transvt'rse section through corpus trapezoideum of newborn
mouse ............
Nucleus semilunaris of newliorn cat
I'lOK
80(1
806
807
808
810
811
813
814
815
816
817
818
819
820
822
824
825
827
82!)
833
834
838
842
844
845
846
847
848
850
853
855
856
857
858
8.")9
800
\
'■' ■ I!
LIST OF lLLlS'riL\TI().NS.
x.\i\
MOT
Stj!)
H70
871
873
874
870
877
878
87!)
KKirnK I'AliK
r)."»(). ('ill's brain lifter section of li'imiisciis lateralis .... Mfil
.>")!. Trunsilion of eoi'[ius lra|ie/.()i(leuiii iiilo lemniscus lateiiilis . . HiV.i
,").■)•,'. Same as Fig. :jl4 805
'i'}'-]. 'I'l-aiisverse section of colliciilns infei'ior of eat .... 880
554. Termination of axoncs of nerviis cochlea' in t lie central nei'vniis
system ............
J).").!. N'ciiroiies with descending; axones in the central acoustic |)aths .
ij.lO. Relations of leniiiiseus lateralis to corponi (|ua(lrigeiniiia
557. Optic and acoustic reflex ]iaths
558. ("orims traiiezoideiun in lirain of rahhit ......
55!). Frontal section of human brain in which liiere was a lesion caus-
in<j (lej^cneration of corpus genieulaluni inodiale, inicleus
ruber, substantia nigra, zona incerta, and eollicuius inferior .
560. Sagittal section of babe's brain .shortly after birth ....
501. Sagittal section through liiviin of a l)al)e at the eml of the second
month of life
563. Frontal section through iiemispliere of a child i'oui- and a half
months old ..........
563. Nerve cells in the cortex of gyrus temporalis superior .
5G4. Horizontal section throiigh brain showing relations of auditory
sense area to the speeeii centres ......
565,560. Scheme uf auditor} conduction patii
507. Schomo of structure of spinal (di'd
508. ("ells in a frontal longitudinal section through thoracic spinal
cord of newborn babe ........
56!). Motor cell from ventral horn of spinal cord of rabl)it .
570. Ventral horn cell from lumbar cord of ox
571. Transverse section of spinal cord of /jiici'itd (tfjilin
572. Spinal I'ord in connection with medulla oblongata and pons.
573. Nerve plexuses and terminals from nniscle of lizard
574. ^lotor telodendrion from Luci-rfd ih/i/ih .....
575. Motor nerve ending on the M. gastrocnemius of the frog
576. Nerve ending on an intercostal muscle of the rabbit
577. vSchenu' of lower motor neurone .......
578. Muscle nuclei of human cervical cord
579. Spinal cord of adult man showing grouping of nerve cells: level
ofC. II
580. Transverse section of human spinal cord at level of ('. V
.581. Transverse section of human s]iiiial cord at level of C. VIII .
.58'J. Transverse .section of human fietal cord
583. (}rou|iing of cell bodies of lower motor neurones innervating
various muscles 910
584. Diagram of human spinal conl at level of t'. Ill, from a case of
poliomyelitis 911
585. Columns of gray matter and motor nuclei of intuniescentia cervi-
calis !)12
5H0. {'olumnsof grav matter and motor nui-lei of intuinescentia hunbalis 913
88(J, 881
. 886
889
8!)0
8!)1
■SOI
893
894
895
890
8!)6
898
905
900
007
908
!)09
"^m
m
I
tt:
xxx
TFIK NKHVors SYSTEM,
f!l'
i
Kic.r
-WT.
B88.
58! t.
")!)().
rm.
5!);!.
504.
596.
5!)T.
0!)8.
rim.
GOO.
«oi.
602.
603.
604.
605.
606.
607,
609.
610.
611.
612.
6i:?.
614.
61.5.
616.
617.
618.
619.
620.
621.
£1
i
i
IJniiii sliowiiifj ttic orijfin ami tfi-riiiiinlioii of ncrvi corpbrnlos, hii-
iimii einlji'Vd ..........
C'cruljniiu wit li portion of sjiiiml (MH(1, Vein rill siii'Ijicc .
I'"irsl ('('iiluiiic cavily, prircordiiil jxirt of siviill I'mm Lunita riridl.s
l)t'vclujiiiient. of iiiusi-ic'S of mastication ......
Hniiiryo of Lacerfu viridix to show origin of niusflcs of tongue ,
Uiiigrani of sensory coniponents of (.•crchral nerves of Minidid .
Same as Fig. !i25 .
Same as Fig. 410
Transverse section at tlie juiiel ion of pars eervii-alis of the eonl
Willi miHiiiihi oblongata siiowing noiviis ac'cessorius
Same as Pig. iJ12
Same as Fig. !!i;i
Sagittal section tiirougli riiumliencephalun of fu'lus
Scheme showing motor and sensory neurones of nerviis trigeminus
Frontal section through brain stem of lu'tal mouse showing nuclei
of nervus trigemini
Same as Fig. 32 1
Same as Fig. ;{14
Same as Fig. 317
Scheme of th(! nuclei nervorum (Kiilo-motoriuni ....
Nucleus originis et fila I'adicuiaria \. oculo-motorii of emi)ryo duck
Same as Fig. 557
608. Schemes of relle.v mechanism of spinal cord ....
Section through medulla oblongata and upper cervical cord show-
ing non-medullated olivo-si)ina] fasciculus ....
Dorso-lateral view of nucleus olivaris inferior ....
Ventral vimv of nucleus olivaris inferior
Same as Fig. ;!11
Descending degeneration in s])inal cord after section of corpus
restiforme ..... .....
Degeneration following section of corpus restiforuie
Cross section of cervical cord showing degeuei'at ion after section
of corpus restiforme of dog
Section showing relation of inicleus lateralis superior through
faseicidus longitudinalis meilialis ......
Section througli pons showing degeneration after removal of left
hemisfjhere. ..........
Section showing degeneration of decussatio pyramidum after re-
moval of left hemisphere
Section thi'ough cervical cord showing degeneration after removal
of left hemisphere .........
Large pyramidal cells of cortex
Diagi'am of giant jiyraunMid cells in gyrus centralis anterior in a
man forty-three years old
Nornnil Hetz cell from hunnin paracentral lobule ....
Section through gyrus centralis anterior
916
918
920
921
922
92:5
925
927
028
031
034
035
036
037
930
940
041
044
946
948
953
955
057
958
961
965
966
067
970
971
973
973
077
978
979
080
LIST <M' n>I.FSTUA'n()NS
XXXI
KKU'KB PAOB
((24. Sclu'iiic (if (IcciisMilic) |)\ riiiTiiduin ....... 088
()2">. II(iri/(iiiliil scclicpii lliidiij^li j;1(i1mis jmllidus in iicwlKprii liahc . 085
((2(>. Ilorizdiiliil .section iliroti;,^!! iiucitMis li'iitifiirmis in ncwhorn Imlic . 9H7
((27. Horizontal scdion throuj,'!! nuclens lentifonnis in newborn Ijahc . 988
028. I[(iri/,onlal section tlinuij.;!! imclciis lentirorinis in newborn ])abe . t)89
029. Section at rigiil aiij:;le.s to liic longitudinal liiiri's ol" the basis pe-
(Innculi (junction of upper with middle third); newborn babe,
no to T)! cm. long 990
630. Transverse se('tit)n through the spinal cord of a newborn babe,
about 50 cm. long ; level of sixth cervical nerve . . . 991
(Wl. Transverse section through the spinal cord of a newborn iiabe,
about 50 cm. long; level of fourth lumbar nerve . . . 992
632. Early experiments of lieevorand llorsley at motor cerebral locali-
zation 990
033, 634. Motor cerebral localization in the monkey . . . 998,999
035. Comparison of motor representation in the bonnet monkey and in
the orang-outang 11)01
636. Sagittal section through the brain of the monkey, illustrating the
internal capsule 1004
637. Position of fibres at various levels in the capsula interna of the
nu)nkey 1005
638. Horizontal section through the right cerebral hemisphere cut at
a distance of 01 mm. Vielow its superior border . . . 1006
639. Drawn from a photograph (nuignifled twice) of the outer surface
of a monkey's left hemisphere 1009
040. Experimental stimulation of fresldy cut substantia alba of dog's
s[>imil cord 1011
041. Degeneration following hu'morrhage of six months' duration in
the nucleus lateralis thalami and in the lenticulo-optic por-
tion of the (^apsula interna . 1013
642. Portion of pyramidal tract in cross section which has urulergone
secondary degeneration ........ ll)15
643. Seeoiulary degeneration of motor fibres from the ])allitnn alter
extensive cerebral lesion lOlH, 1019
644. Non-medullated fibres in the lemniscus at l)iith corresponding
to the centrifugal bundles of the lemniscus .... 1031
645. Brain of monkey showing cortical area extirpated . . . 1024
646. Horizontal section of monkey's brain showing area of degenera-
tion in internal capsule, following lesion of hallux centre . 1025
647. Degenerated area in Fig. 046, eidarged 1025
648. Decussatio pyramidum, hallux lesion, showing degeiu-rated fibres
passing to fasciculus cerebro-spinalis lateralis of both sides . 1026
649. Spinal cord at the level of the eleventh thoracic root, hallux
lesion. Bilateral degeneration 1027
650. Section of spiruil con! at the level of first cervical root; degen-
eration in right fasciculus cerebro-spinalis lateralis after ex-
cision of thximb centre of left hemis|)here .... 1028
1 ■' '
•':.i|i
m%
■^
XXXll
THE NKItVoUS SYSTEM.
KimilK PAdB
(i.-)!. Horizontal section of monkey's l)rain sliowiuff locution of degcn-
enil ion I'oJlowing lesion oi' t lie fiieiiil ureii .... IO"J!»
•).")2. Dcf^'eiieniled iireii in i-'i;,'. (Jo! enliir^etl lOtiO
<io;f. Horizontal section ol' monkey's i)raiii tliruii^'li basis |)e(liii!cnli
sliowinii: location of ilef,'eneration lollowin;; excision of an
iireii nnirked F in Fif,'. 01.1 lOJH
fi")!. I)e;;eiiel'ali'il area ill l''i^'. <ir);5 eiilar;4C(l lOJJ^
tioo. Sclieine sliowinji III" I'rohablu course of iiii|iiilses and the iiitiT-
n(Mironul connections in Mie cortex cerebri .... lOJU
<>•"»<!. I)iai,M;mi of t!u! cells of the cerebral cortex lOo.l
ti.")7, tioH. .Schemes of upper and lower motor iienronus, . . KCiT, lO.'fH
fl5!(. Scheme of frontal cerebro-corticopoiital path .... 1041
<i(IO. l-'roiital section tlirc>iiu:li the ret^noii of the nucleus \. trochlearis
and tluMlccussutio braciiii conjunctivi 1042
(!<il. Secon<lary dejfcneratioM followiiif,' lesion in the lel't middle and
inferior frontal ;,'yri 10415
(iti'J. Zone of the cereijral cortex, lesion of which causes de<,M'neration
of ail the lilires (if the basis pcdunculi 104G
ti(i;i. Cortex of human brain iiliislratiiii;' the systems and plexuses of
nerve libres 1050
'ifll. Safjittal section til roujtfli the lirain of a babe shortly after birlii
illnstratiiif,' the |irojection libres to the soina'sthel ic area . 10.")1
GOo. .SclieiiK! <d' H transverse section through the brain slnnviiii,' the
jiroliaiile disposition of the commissural and projection fibres 1054
(>(!<). Scheme of the cominissiira anterior cerebri ..... 105G
tiUT. .S(dicme of an antero-posterior section tlirouj,di the cerebrum
showiii'^ the dis|)ositiou of the axonesof association neurones
which connect the lobus frontalis with the lobus occi|)italis . 105!)
U()8. W'rtical transverse section of the left occijiital lobe to show the
orij;in aiul course of the slK)rt association tilires of the lobus
occipitalis. .......... 1000
00!). Faci(.'S mcdialis lieiiiis|ilia'iii sinislri sliowiiij;;' the ciii^ulum, th
fasciculus loiiifitudiiialis inferior, and other bundles of asso-
ciation fibres .......... 1003
070. ^larchi preparation showini; deyeiieralion in doy's brain after
destru(!t ion of the lobus frontalis lOOlJ
671. Lateral surface of the left cerebral hemispiiei'e .... 1004
672. X'crlical transverse sct^tion passinj,' throuf,di tiie posterior part of
the pra>cuneiis. the fissura parieto-occipitalis. the (issura cal-
carina. etc 1000
673. Two vertical transverse sections from a cerebral liemispliere. with
aLTciicsis of the (!orpus callosum 1068
074. I'^isciculus occipito-froTitalis. taenia semicircularis. and fasciculus
uiiciiiatus. 1009
075. View of lateral surface of ri.ii;lit cerebral hemispliere showing
sense centres and as.sociat ion centres 1072
676. View of the medial surface of the left cerebral hemis])lier(> show-
ing sense centres and association centres .... 1073
TiiK NKiJvors systi:m and its
(X)\sTiTrh:xT N!orK()Ni^:s.
siocrrioN r.
THE HISTORY OF THE DEVELOPMENT OF THE
NEURONE CONCEIT.
("II A ITER I.
INTUODI'CTOIIY.
'I'iic stiiily of nciiroloji^y — (»liler views rcpinliiijj iku'vc mAU ami iicrvi; fibres
— Dcitcrs' stiiilics — I'routisscs of iicrvt' (-t'lls — I'nitoiilasiiiic iiiid iixis-
cyliiider proccssos — von (ierlach's studies — Idea of a ditliisi! iiervo
network.
In i'ucc of the iiuiiiy (lUi'stioiLS {loiiconiiiij,' htiotorial toxi-
cology, intenml secretion, Holf-iiitoxicatioii, serotherupy, and
organotherapy, subjects all fraught with jiractical import sufli-
cicut to explain the abHorl)in<i; interest in nu'dical circles regard-
ing them, one might have had some hesitation in choositig as a
subject the title given above, were it not that tliis topic is the
one wiiicii more than any other since the beginning of scien-
tific! records has occupied and must ever occupy the minds of
thoughtful physicians in all countries of the world. And oth^
cannot but feel that when these burning (|Ucstions of to-day
shall have been settled or supplanted by others, subscciuently
thought to be more important, the problems conneiited with
the nervous system, that portion of man's organism whi(di in
the main is accountal)le for the high ])osition he has assumed
among the animals, by nu'ans of whi(di, in addition to the
advantiiges of reflexes aiul instinctive reactions, he is able not
only to gatlier multiple experiences, but to comnnmicate them
to his fellows and to utilize them in bettering his condition,
to study, to investigate, and to si)eculate — these problems will
2 1
-Hll
Till") NHKVOl'S SYSTKM.
I
Htill rcniuin tlio niowt iittractivc iiikI nlKsorbiii;,'. At tho end of
a (li'cadf which has witiicsscMl an iinprcccih-iiti'd activity in this
domain, the results of which have I('<l to a coinph'tc revolution
in our ideas concerninj^ the elcMU'uts of the nervous (ir<,Mns and
thoir architectural rehitions, and have supplied us with a host
of new methods of invistifjation, the study of ni'urolof^y, espe-
cially of the human nervous system in health and in disease, is
parti("ularly alluring'. Kntirely new avenues of research have
heen opened up, and ])roblems hitherto thoii^dit to be situated
almost outside the limits of scientific inquiry now seem at least
within lunnan 2)oasil)ility.
It may be staved in the be^innin<i; that it has seemed to me
advisai)le to gather to<:;ether in as simple a manner as possible
some of the more general results of modern neurological inves-
tigation and to hint rather at the outlook for the future than
to detail at length the results of any single origiiud research.
Nor would it be |)ossible in the space at my disposal to cite
even the nuiin results obtained in all the diU'erent directions in
wiiicli neurological iiKpiiry has been pursued. I shall have to
be content with reviewing some of the main achievements in
the departments with which I am most familiar, leaving it, how-
ever, to be distiiu^tly understood that in the others nniny just
as important conclusions have been arrived at and much funda-
mental experimentation is still in progress.
Entertaining as it could be made, it is not my purpose to
give a review of the evolution of the various doctrines held at
different times regarding the structure and function of the cen-
tral and peripheral nervous system, nor to describe tbe gradual
modifications and inventions in anatomical and histological
te(dini(|ue which have been evolved with eacdi new tbeory and
which have opened up new fields for study. It will be neces-
sary, however, in order to make clear the phenomenal advance
represented by the ideas which at present prevail, to speak
briefly of tlu' unsatisfactory state of the views which imme-
diately preceded them.
Considering the remarkable activity manifested during the
epoch-making period of 1838-'40, when, incited by the publica-
tions of Schleiden and Schwann, anatomists busied themselves
in ransac^king all regions of the body, hunting for " cells," it is
not surprising that a number of them turned their attention to
the nervous organs, concerning the liner structure of which
DKVKLOPMRNT OF TIIK NKI'IIONK CONC'KI'T.
little wuH tlicTi known. Klirciihcrj,', uh early U8 is;{:{, in stuily-
iiij; the spinal ^'an;,'lia and Mie (central nervoiiH Hystein, Imd
uinloiihtedly seen the j(an},di()n cells in the former Hn<l the rne-
(lidlatcd fibres in the latter, alt h(»ii<,di lu' descrihed them as capil-
lary tiilies. After him, N'alentiiie and I'urkinje jjjave hetter
(lescri[)ti()ns, the former of the spinal ^'an<,di()n cells, the latter
of the ganj,dion cells in the brain. Kminert, lleide, and Uosen-
tlial studied the dill'ercnces in size and nund)er of the lihres in
the ventral and dorsal roots of the spinal Jii-rves.* Hut to
KcMiak and llelmholtz helonjis the credit of showing; that a
portion, at least, of the processes of the nerve cells of verte-
hrutes fjo directly over to form nerve fibres, nt any rate in the
sympathetic system. Von Kolliki-r in IS 14 described the nni-
|>()larity of the cells in the ganglia of the dorsal roots, and the
origin of medulhited nerve fibres from them, although it was
not until 187/) that Ranvier demonstrated the T-sliaped division
of the process at a distance from the cell, while the real expla-
nation of the unipolarity and its relation to the bipolar condi-
tion in fishes was first worked out in the end)ryological studies
of His.
With regard to the connection of the nerve cells, within the
central nervous system itself, with conduction juiths, the first
observation is that of Wagner,t who in 1S47, while studying the
electric lobe of the torpedo's brain, found that of the numerous
jirocesses possessed by the nerve cells oidy one or rarely two
remained unbraiudied and became connected with a nerve fibre,
a finding whicli Remak in isr)4 asserted also for tlie cord and
brain of the ox, and which in the following year he stated was
true in general of all motor cells. The most important oltser-
* Tlio (list'overy tliat the ventral roots of the spinal nerves are eoiicerned
witii motion, tiie dorsal roots witli sensation, had lieen made earlier l)y tiie
eminent British snrfjeon and anatomist. Sir (Uiarh's Hell. His views on the
structure of tlie nervous system are eoiitained in the foliowinfj three works:
(1) Idea of a New Amitomy of tlie Urain ; Sulimitteil for tii(> Ol)servations of
his Friends, ;J6 pp. 8vo (liondon, IKll); (3) An P.xposition of the Natural
System of the Nerves of tiie Human JJody, with a Uepuhlication of tiie
Papers Delivered to the Hoyal Society on tlie Huliject of Nerves, vii, 3i)2 pp.
Hvo (liOndon, 1824); (."$) The Nervous System of the Human Hody, etc., 4to
(boiidon. 18;i0: third edition, Kdinlmrj^h, 1844).
+ Wafjner. R. Ueber der feineren lUui d(>s elektrischen Orpins ini Zitter-
roclien, 4to(Gotlin};en. 1847) ; also, Neue I'ntersiiehungen iilier den Hau und
die Fndigung der Nerven und die Struktur der Ganglien (Leipzig, 1817).
I
/
4 TIIK NKHVOrS SYS'l'KM.
viitioiis 1111(1 j,'{Mu>niliz!iti())is of tliis period were, liowovtT, made
by DcitjTH, tlio (listin^Mi'shcd invt'Hti^ator iit lioun, who, liko
niiuiy others wlio hjivc siiccfSMt'iilly pursiUMl scientific studies,
died iit 11 coMipiirutively curly a<,'c.*
Deitcrs iimde an extroniely careful study of the various pro-
cesses of nerve cells with the best te(!hnical methods at his dis-
posal and classed them all in two ^jreat f,'roiips : ( 1 ) I'rotoplasriMc!
processes which were branched and the internal structure of
I'"l(i. I. — .Miillipdliir Kiiiittliciii cell fniiii tlic vciilriil Imni nf tlic <;rii,V niiittcr iif
the spiicil ciinl iif llic ox. ( AlltT Dcili rs. i n, iixis-cyliiidcr pi-nccss ; h, |>ro-
t(p|(l;tsliiir proiM'SSCS.
which corresjionded closely to that of the body of the nerve cell,
the i)rotoi)!asin of the process bein<j granular, and sometimes
even pigmented; and {'i) axis-cylinder or nervous pro(!esse8
consisting of a rigid hyaline, more resistant substanc^e which at
a short distance from its origin in the nerve cell ])iissed directly
over into a medullated nerve fibre (Fig. l).t
♦ ottii DciliTs" l)iiok, rntcrsiic'liuiiKeii iituM- Ocliini uml Itilckcnmiirk dcs
Moiisclicn 1111(1 del' S;iiiifctliit'i'(\ I5rjiiiiiscli\veiy;. 1^0.1, was issued by IMiix
Scliiiltzo, two yt'jirs iiflcr tlic autlior's di-Mtli.
t In rciility, Deitersdosoribosi two kinds of iixis-cylindor procpsscs. eoarse
mid fiiif. till' description in tlic text fip|>lyini,' to tlie foriner. lie tlioutflit
tliJit the liner iixis-cylinder processes could be present in larjj:c numbers oil
single nerve ceils, arising from the protoplasmic proensscs and going over
into t lie fine medullated fibres of the central nervous organs. Tliese tlneraxis-
cyliiuler processes liave becii recent ly proved iiy t lie delicate histological meth-
ods of Held to be the terminals of axis-cylinder processes of other cells thus
ending on, not, arising from, the cell with wliiidi they seem to be connected.
DKVKLOI'MKNT OF TIIK NKI'lJoNK CONCKI'T.
Waldcycr, in IiIh excellent review of the tiiorc recent inves-
tipitions into the aniitoniy of tlie nervoiiM Hysteni,* lays eni-
iiliasis upon tlie point tliat despite tliv enormous value of his
researches Deiters did not actually demonstrate the connection
of a <,'an},dion cell of the central nervous system with a periph-
eral nerve lihre, a fact to whicdi Kolliker and (ierlaeh had pre-
viously nuule reference. The eoiuuu-tions of the axis-cylinder
processes of the cells of the ventral horns with the axis cylin-
ders of the tihres of the motor roots of the spinal nerves were
first ahsolutely cstahlished by the use of Weif^ert's mordant
methods of staininj? the myelin sheath, f The countinfj experi-
ments of Hir;(e J in Ludwij^^'s laboratory showed a remarkable
accordance in the number of ventral horn cells and that of the
lihres in the ventral roots, and led many physioloj^ists aiul anat-
omists to the belief that each motor fibre in the ventral root
is connected with a corresponding cell within the gray nuitter
of the cord.
More widely reaehitig in inllueiu-e, for some time at least,
were the studies of (ierlaeh'* with the gold nietiiod ami the
hypotheses which he based u))on them, hypotheses which were
responsible for an immense amoutit of polemical writing during
the fifteen years which followed their introduction, (ierlaeh,
bv means of methods of isolation and treatnuMit with chloride
of gold, obtained pictures surpassing by far, in extent and deli-
cacy, any obtainable with the older methods, aiul affording an
entirely new concept of the complexity of the structure of the
* Waldeypr, \V. Uetipr ciiiijjp npuoro F'orsohunpon im Gobieto der Ana-
tdtnic (los ('(Mitnilnervcnsystciiis. Deutsclie mod. Wdmschr., Iii'i|)Z., IHill,
IW. xvii. S. 1244. 12(i7. 1287. l:Wl. lli.Vi.
t Carl Woifijcrt's m.'thdds and tlic carmiii mothddsof (icrlacli in conjiuic-
tion with improved t('('lini(|ii(' in sectioniiin; have contributpd enormously to
llip advance of investigations in neurology. For the application of Wei-
gert's methods to the nervous system of lower animals the experiments of
C.J. Merrick maytic^ referred to with advantage. (Cf. Ilerrick. ("..I., {{eport
upon a Series of Fxperimetits with the Weigert ^tethods — wiMi Special Hef-
ereiice for Fse in Ijower Hrain Jforphology. The State Hospitals HuUetin,
l^tica. vol. ii. 18!t7. pp. 4:51-461.)
!(. Hirge, E. A. Die Zahl der Nervenfasern und der motorischen fiangli-
enzellen iin Hi'ickenmark des Frosehes. Arch. f. Anat. u. F*hysiol.. Leipz.,
1882. Physiol. Abth.. S. 4:{r)-48().
* V. (ierlaeh. .1. Article. The Spinal Cord, in A Manual of Histology by
S. Strieker. American Translation. New York, 1872.
mi
-.ss^
6
THE NERVOUS SYSTEM.
gray matter of the spinal cord and Itrain. In addition to tho
bodies of the nerve cells and their main processes, protoplasmic
Fig. 3. — Network siipjioscd liy (Jcrliicli to Ix' foriiicil of the iinitopliisinic processes
of the IK TVe cells. A ln'aiii liiliK iif'Ve tilire from tlie conl of tlie ox is shown
whose two hniiiclies are connected witli a (ihre network which is lii rehiti<in
witii two nerve ceils. ( .Vfler ( ierlacli. ) 'i'liis condition has iieen shown hy
(lolni's method iiol to accord with the facts.
and nervous, the new method revealed the most intricate and
involved appearances, which led (ierlach to believe that he bad
discovered a most extensive and delicate diffuse network within
li
I)EVKIjO]»MKNT op tub NKrilONK CONCEPT.
^1
the gray matter (Kig. 'i). Not satistiod with the simple descrip-
tion of his tindings, he jiroeeeded to set up an interesting hy-
potliesis, 1)ased hirgoly upon the physiological ideas which pre-
vailed at tlie time, regarding protoplasmic^ co!itinuity.* He
concluded tluit he had to deal with a comjdex nerve network, f
consisting of a genuine reti(nilum of deli(!ate lihrils resulting
from tlie fusion of the ultimate dendritic bran<diinga of the
proto])lasmic ])r()cesses of the nerve cells of the central organs.
From the far side of this network, tiirough gradaal fusion and
concentration of the threads belonging to it, broader fibres
slowly a))peared, which liiudly were to be recognized as genuine
nerve fibres, becoming medullated and forming the fibres of the
dorsal roots (sensory fibres) and in part the white fasciculi of
the spinal cord. (ierlaciTs view, tberefore, was that the axis
cylinders of motor nerve fibres represent nervous processes com-
ing off directly from nerve cells, while the sensory fibres of the
dorsal roots are to be looked upon as nerve fibres arising from
nerve cells oidy indirectly througli tiie interventioTi of a diffuse
nerve network made up of their protoplasmic processes. Thus,
according to his scheme, with whi(di Holl and llaller essen-
tially agreed, the whole nervous system represents a })rotoplas-
mic roil/ inn fan — a veritable rcfe inivabih' (Fig. 3). Such was
the state of affairs at the time when what we are accustomed
to call the "newer investigations" were begun. A more un-
satisfactory condition of knowledge or a more prohibitive
hypothesis can s'-arcely be conceived ; all ideas of tracing out
* This assiiniplioii of |)rot()|)lasmi(' coiititiuity has also been mado uso of
by .Mr. llcrlitTl, S|)('iic(!r in liic (li'vclopinciit of his (loctriiic of tli(> fj;('iiosis of
iicrvoii.s systoins. I'rinciph's of Psychology, New York. D. Applcton and
ConipaTiy, vol. i. p. WO. 'V\w botanists, followinj? ospocially tho rcscurchos
of (ianlincr, teat'h at present, thai in plant tissnes the protoplasm of all the
cells forin.s a conHnunni, a fact which hinders many students of animal his-
tolo<,'y from assertiiii; too jiositively the non-existence of such >i nmh'innnn
in the tissues of adult animals. The demonstration comparatively recentlv
of the so-called plasma bridges connecting ejiitlielial and endothelial cells,
and also perhaps the elements of other ti.ssues with one another, is interest-
ing in this connection.
tin gold preparations it must have been extremely difllcull, and was
probably impossible, to distinguish a network from a fcltwork. A German
investigator, sju-aking of the frightfully intricate complex of fine ncrvo
fibrils in the central nervous system, referred to it as the liirrji/z ih-r grauen
Sulmtanz. —
ml
t
8
TIIK NKHVOUS SYSTEM.
definite conduction paths or of localization of function within
the central nervous system seemed well-nigh hopeless ; in the
Fui. '.i. — SclH'iiif of ('(iiiiicctions of (Inrsjil and vt'iitnil roots of spinal cord accord-
iiifj lo a discardi'd tlicory. (After Kanion y Cajal.) (/, (il)r(' of dorsal root
supposed to liave its origin in Clarke's nucleus; /«. unipolar cells of spinal
ftan^lioii ; il, lerniination of a dorsil root fibre in the reticulum of the dorsjil
li<it<ii • /• rjMit MKrii frjiiiKr tii li!icu litli iri 1 1 w1 i ti!i 1 1 V ill tlii> )<it«>l*;i1 I'litliiim * 1' i\]iVi^
inirn ; c, root fibre K'uuf; to i)ass loufiitudinally in the lat<'riil coluiun ; /. fibre,
from Clarke's nucleus ilirectcd toward the latenil colunni ; <i. lateral column ;
/(, motor cell connected with fibre of ventral root. / ; j, fibre of vent nil root
comiiif; from a cell in ventnil horn of ojiposite side ; k. column of Clarke : in,
ventral median fissure ; ii. column of Ti'irck ; p. cell of ventnil horn, th.' ju-o-
toi>lasmic processes uuitiuK to form a lU'twork, (/, in which the fibres of the
dorsal root terminate: c, cells of dorsal horns, the i)rotoiilasmic processes of
which are united lo the lU'twork, (/ : s, ascending fasciculus of lateral col-
umn : t. lateral pyramidal ti-.ict ; ii. r. fibres of dorsal root terininatint; in the
network; .r. fasciculus cuiu'atus of Hurdacli ; //, fa.sciculus Knicilis of (ioll;
i', median dorsal sulcus.
genenil diffuse network investigators were halted by what ap-
peared to be an insuperable btirrier.
i;f
'M
n) '■
I
CHAPTER II.
THE STUDIKS OF HIS, (iOLOI, AXl) FORKL.
The nowcr iiivostigations— (iolgi's riictliod— Tyi)cs of nerve ecHs descrihed
by(Ji)lgi— ("ell of Type 1 iind cell of Type II— Golgi's hy{)othcses— Con-
tributions of His and Korel— ( tpposition to the idea of a nerve network
— Orifjin of tlie idea of a nerve feltwork or neuropileni — Doctrine of
the individuality of the nerve elements— The principle of contact for-
mulated.
Then followed a series of researches, the majority of which
date since the year 1880, and with which the names of Ciolgi,
His, P'orel, Kulliker, Ramon y Cajal, van (lehucliten, Retzius,
and von Lenhossek are inseparably connected. These investi-
ffiitions led to a complete revolution in the ideas regarding? the
elements ot which the nervous system is constructed and the
mode in which these elements are put together in its architec-
ture. It may surprise many to learn that tlie now world-famed
(iolgi's method was first described by its inventor, Camillo
(lolgi, of Pavia, as early as 1873.* But little attention was
paid to it by investigators in other countries, however, until
more than twelve years later, when he published his volumi-
nous article. Concerning the Finer Anatomy of the Central
Organs of the Nervous System.f The method is now so well
known that it is unnecessary to describe it here in detail. It
will be recalled that it depends upon the treatment with a solu-
tion of nitrate of silver after previous immersion of the per-
fectly fresh tissue for a longer or shorter time in a solution of
* Golgi. (". Sulla struttuni della sostanza gripia del cervello. Gazzetta
niedica italiana lonibnnlia. t. vi, IHTIJ. (Jolgi's contributioT)s to the bibliog-
raphy of the nervous system have been collected and translated inloCierman
by Teuschcr. Cf. (Solgi. C, Untersuchungen ilber den feineren Bau des
centrnlen imd {)oriphprischen Nervensystems, .lena, Fischer. 1S!)4.
t Golgi, ('. Svilla fina anatomia degli organi centrali del sisteina ner-
voao. Riv. sper. di freniatr., Heggio-Kniilia, 1882. vol. viii, pp. 165, 361 ;
1883, vol. ix, pp. 1, 161, 385; 1885, vol. xi, pp. 72, 193.
9
ill
h
I
ifW
10
TIIM NKKVOUS SYSTKM.
i!
■I
•i-i
bichromate of potiissiutn.* 'Vlw iiorvo cells and their processes
stain ijitensely bla(^k and stand out prominently on the white
or yellow j^round. Thi; pi(^tures obtained are in extent, clear-
ness, and sliarpness, at least as far as tiie external form of the
element is concenied, incomparably superior to those obtain-
able by any other known technical method. f As a rule, cer-
* The slow chroiiiate of silver metliod reeoniinoiuled by Ooljifi is used as
follows: Pieces of tissue are hardened in Midler's fluid foi ai least one or
two niontlis. They are then traiisfeiTed to a hath of dilute silver-nitrate
solution, where they remain for from one to three days, after which the tis-
sue may be out into sections, after very rapid imbetltliuf,'.
The methoil n()W almost uiuversally employed is the (jnick method in
which osniic acid and potassium bichromate arc used. Small pieces of liv-
iiifj tissue, not exceeding four millimetres in thickn(!ss, are fixed, at a tem-
perature of 'i'") ('., for from one to four days in the followinj^ mixture,
rec'ommcnded by Ramon y Cajal: Bi(;hromate of potas.sium, !J {jrin. ; dis-
tilled water, 100 c. c. ; one-per-cent solution of osnuc acid, 30 c. e. For each
piece of tissue, four millimetres s(|uarc, ten cubi(^ centimetres of this mixture
should be employed. After the fixation the pieces are (juickly washed in
distilled water, and then immersed in a 0.75-per-eent solution of silver
nitrate. They are permitted to remain in the silver bath for fi-om one to
thi'ee days. They are then very rapidly imbediled in celloidin and cut into
sections, .serial if desired, with the aid of a microtome. The sections are to
be quickly dehydrated by passing them through sevei'al dishes of ninety-
five-per-cent alcohol. The tdearing is iiest done with oil of bergamot (Berk-
ley). On the slide the excess of oil is removed with blotting |)aper pressed
directly upon the sections (Welch), and a drop of thi(^k balsam is plaix'd
upon each section. No cover slip is to l)e applied. If desired, the sections
may be mounted upon thin glass or isinglass, which may then be fastened
to a glass slide by means of glass beads, the side on which the sections are
being down, to protet^t them from dust (l"]dinger).
For some researches the modification of Cox can be csj)ecially recom-
mended. According to W. II. Cox (Tmpn'iguation des centralen Nervensys-
tems mit (^uecksilbersalzen. Arch. f. mikr. Anat.. Hd. xxxvii (18!»1), S. 16),
the fresh tissues arc to be hardened for from two to five months in the fol-
lowing fluid: Of a five-per-ccnt solution of bichromate of potassium, 20
parts; five-per-eent solution of l)ichloride of mercury, 20 parts; distilled
water, 40 parts. Mix, and add five-])er-cent solution of chromate of potas-
sium, 10 parts. The tissues are then to be washed for half an hour in
ninoty-per-cent alcohol, then imbedded and sectioned (preferably with the
freezing microtome) as in (lolgi's method. The sec^tions are placed for
from one to two hours in a five-pcr-cent solution of sodium carbonate, or in
ammonia solution : then washed in distilled water, qidckly dehydrated,
cleared, and mounted in balsam without cover glass.
•f Such pictures alTord suitable objecsts for reproduction by photography.
Compare the beautiful Atlas of Nerve Cells, of Starr, Strong, and fjcaming.
DKVKLOPMENT OP TUK NKUROXE (^ONCKPT.
11
tiiin only of tlio nurve structures present are foutul to he iin-
picgniited in a successful preparation. Whether this elt'ect is
dependent or not upon functional conditions of the tissues at
Fio. 4. — (lolfii's cell i)f Type I. (VU IVoiii tho optic tnict <if the cut iatcnil froiii
tlic lateral Keniculate t)o(ly. (After Kolliker. ) Railiatiii^ from tlieeell Ixidy
are to l)e seen very many protoplasmic processes wliicli show a broad wedm?
of (irifjin and branch charaeterislicaily ; the sin;;le axis-cylinder process u
has a smooth snrface and tolerably even I'alibre. which is niaiiitaine<l for a
considenible distance from the cell. It sivesotl'a fewdelicate lateral branches
or colhlteriils. c.
the moment of immersion we do not as yet know ; certain it
is tliat a distinct advantaaje is {gained, imismnch as the elements
iire represented, as it were, in a dia<;rammiiti(^ manner, and the
study of them is in a high degree facilitated.*
New York, 1806. ami the pliotof^rapiis by Iloeii illiistriiting Berkley's pub-
lications.
* .\ vnliiablo t'riti(|iie of the Golfji inotliod, its nature and results, is that
of A. Ilill, The Clirome-Silver Method, Brain, Lond., vol. xix, 1806, pp.
12
THE NERVOUS SYSTEM.
t
(Jolgi, by the iippliciition of these silver methods to the
^M-ay matter of tlie cerebro-spinal nervous system, reco^niized
nerve structures varying,' in cliaracter, which he f^rouped into
two main categories of nerve cells — cells of Type I and cells of
Type II. The cell Type 1 (Fig, 4), as described by Golgi,
agrees in the main with the general description of a central
nerve cell given l)y Deiters, being characterized by much-
branched protoplasmic processes (usually multiple) and a sin-
gle axis-cylinder process. That the latter was unbranched,
however, as Deiters maintained, (Jolgi denied, and his discov-
ery of "side branches" upon the axis-cylinder processes, first
of the pyramidal cells of the cerebral cortex, and later upon
those of the I'urkinje cells of the cerebellum, represents an
advance of a degree of importance utterly beyond (Jolgi's
conception at that time.*
These side branches given off by the axis-cylinder process
of cell Type I are usually delicate, and exercise a hardly per-
ceptible influence upon the calibre of the main fibre, which
retains its individuality at least for a long distance from the
cell, (lolgi noted that these side branches exist also upon the
motor fibres arising from the cells of the ventral horns, and
that similar ones are given off by the fibres of the white fas-
ciculi of the spinal cord, whence they run into the gray matter.
The branching of the axis-cylinder process shows quite a
different behavior, however, in the cell of Type II (Fig. 5),
and indeed it is the axis cylinder which is morphologically
characteristic in the two classes of cells rather than the pro-
toplasmic processes. The axis cylinder of a cell of Type II
begins to divide almost immediately after its departure from
the cell body which gives it origin, breaking up in a dendritic
manner into a large number of fine branches, the main process
retaining its individuality and being distinguishable for a com-
paratively short distance (Fig. 6), and never appearing to leave
the gray matter.
\ot takijig into account certain observations upon neu-
roglia, it may be said that the most important contributions
,1
1-42. r. WpifTort Ims recently reviewed the tecluiuiiie of the Oolfji method
in Merkel-Boiinet's Ergebnissc dor Anatomic ii. Eiitwiek., Bd. v, Wies-
baden, 181)6, S. 7.
* Waldeyer mentions t'.at he himself noted the branching of the central
process of the Purkinje cells as early as 1803.
i
r)EVELOP>[ENT OF THE NEURONE CONCEPT.
13
of (iolgi in thu doiimin of neuro-liistolo<i;y * consist in (1) the
invention of the silver method of stiiiniug ; (^) the recognition
witliin the central re-
gions of cells of (liifcr-
cnt types (Type 1 and
Typo II); (:5) the discov-
ery of lateral branches
from the axis -cylinder
processes and the fact
that the majority at any
rate of the nerve cells
possess only one axis-
cylinder pro(;ess ; (4) the
(h'nionstration that the
protoplasmic processes
branch manifoldly with-
out anastomosing, all
running out to ultimate-
ly terminate blindly.
Unfortunately, (iolgi,
not contented with de-
scribing these objective
findings, gave utterance
to a number of hypoth-
eses, particularly witli
regard to certain func-
tional relations and to
tiu' ultimate fate of the
side Hl)rils given off by
the axis -cylinder procs Fkj. 5. — Nerve wll with sliort ImincluMl axis
esses, which led him and ..niic ccniHiiuiii ..r a cat af,'.d tiKiii <ia.vs.
XIS
I-
( idltii's I'cll Typi- 11. (AI'tiT Van (ifliiiiih-
tcn. )
many after him into a
whole labyrinth of er-
rors. Concerning these I shall have something to say further
on. For the present, it will suffice to state that (iolgi believed
that the cells of Type I were motor cells, and the cells of
Type II sensory cells ; that (Jerlach's diffuse nerve network,
* (lolgi's faiiu' lis an investigator does not depond entirely upon his bril-
liant researehes on the nervous system, ilis studies of th(> difTerent varie-
ties of malarial parasites transformed clinical ideas upon the subject and
would alone have sufliced to make his imuu> lasting.
"^
lilt
'.'■■'' >
; t
lii
■ . :»l
I
I
It
i
h: I
14
THE NKllVOUS SYSTKM.
arisinj; from tlio iniiistomosiH of protoplasmic processos and
counuctc'd witli sensory fibres on the distal side of the net-
Fir». 6. — (lol^i's cell of Typo TI or (icndnixcmo from the ('crchnitn of a cut. (AfU'r
Ktillikcr. ) The coiirsc protophisinic j)ro(i'ss('s, x, iirc <'!isily distiiifjiiisliiilile
from the uxis-cyliiidcr process, «. tlioiiKli the luttcT soon loses its identity,
exhuiistiug itself l>y multiple divisiuii at a short distiince from the cell.
'\
work, had no existence in fact, but that there did exist a diffuse
nerv^ network (infreceio) within the gray matter * made up of
* Golgi has never piotiirod tliis network, and in all his writings lie has
spoken of it in a very indefinite manner and with great reserve. For exam-
ple, in his Studi suUa fina anatomia degli organi centrali del sistema ner-
itr
DKVKLOl'MKNT OF TIIK NKUUONK COXCKPT.
15
the muny braiu'hos of the axis cylinders of the ci'lls of Type II
jiiid the side fibrils of the axis cylinders of the cells of Type I.
Protoplasmic! i)rocesses, in his opinion, possess no nervous
I'luiction, but represent siin})ly portions of the j)r()toplasni of
the nerve cell which run out to be connected with the blood-
vessels or neuroglia cells in order to pither nourishment
from them. (iol^'i believed that the dorsal root tibres on
(•nterinjj^ the cord branch freely and terminate by becoming?
a part of the diffuse nerve network in tiie gray matter, the
sensory impulses reaching the axones of the motor fibres
through their side fibrils, which, he thought, are connected
witli the distal side of the general network. In this way
the deiulrites and the cell body are excluded from the reflex
arc (Fig. 7). Kpoch-niaking as were his actual discoveries,
the admixture with facts of such liypothesea was indeed un-
fortunate.
The credit, I think with justice, has been given by both van
(iehuchten and von Lcnhossek to His, of Leipsic, and to Forel,
of Ziirich, for having directed the first telling blows against the
doctrine of a ditfuse nerve network and in favor of the inde-
pendence of the iiuiividual nerve elements. The distinguished
anatomist* has since the year 1881 busied himself, in the main,
with the study of the morphology and histogenesis of the
nerve organs, and his results in this field may justly bt* classed
among the most striking achievements of a life of indefatigable
activity.
vost), Miliino. 1H8G, \). iil, he says: "Out of all those branching's of the dif-
ferent nerve processes there arises, of course, an extremely coni()li('ated
texture which extends throughout the whole of the gray substance. That
out of the innumerable further subdivisions by means of complicated anas-
tomoscu there arises a network, in the strict sense, and not simply a felt-
work, is very probable ; indeed, one would be inclined from some of my
preparations to believe in it, but the extraordinary complication of the
texture does not permit this to be declared as certain." In a later article,
Ija rete nervosa diffusa degli orpani centrali del sistema nervoso; suo signi-
fieato fisiologico (Rendiconti del U. Istituto Lombardo, ser. ii, vol. xxiv,
1891, pp. 595, 656 ; Traiisl. in Arch. ilal. de biol., Turin, 1891, t. xv, pp. 4;{4-
46;}), Golgi has dealt with this topic at length, replying to the objections
which have been urged against the existence of the diffuse nerve network
and commenting upon its physiological significance.
* The monographs of His upon the chick and his researches upon the
anatomy of human embryos contain results of personal work which repre-
sent a goodly proportion of what is reliable in modern embryology.
.' I
l(i
TIIK NKKVOUS SVSTKM.
His iiivcslipitioiis 1(m1 him nirly to tho conclusion that from
tho hofrinnin^' the forerunners of tiie nerve cells — the neuro-
hliists — are entirely distinct from an<l independent of one an-
other. They appear at first as oval- or ])ear-shaped cells with
smootli cell bodies entirely devoid of proc^osses ; later, at the
end of the cell originally directed uway from the outside of the
'psr
htfpothetieal
diffuse nervHielmri, -r
bl.cap.
ar.proc.
per. 3. 1
Fu). 7. — Scliciiiiitic rciircsfntiiliipii ot'llii' ditl'iisc iicrvi' network siii)poso(l by some
investigators to l)e loniieil Ity means ol'ilie side tilirils ofeell Pype I and tiie
uxones of cell Type II. The sensory til)res of I lie dorsal root are shown eli-
t<'rinK iiit" conneedon with this dill'iise nerve network, and the eonrse of
inipnises eoneerned in simple rellexes aecordinj; (o this view is shown hy the
direction of the arrows. I5.v this means the cell liody and protoplasmic jiro-
cesses were snpposed to lie exchlded from the rcllex are. Tlii' dendrites were
snjiposed to be pnrely nutritive in function, passing out, to lie connected with
the walls of hlood-vessels. whence the nutrient suppl.v was derived, as shown
in the tijinre. .\ll th<' evidence ;.'oes to show that this view is hicniiu'ct. r. /(.,
Ventral horn of Kra.v matter; it. h.. dorsal liorn ; .''./., side lihril from axis
cylinder of motor cell of ventral hoi'n passing hack into the hypothetical dif-
fuse neive netwcu'k ; /<)'. jinii-., jirotoplasmie jiroeiss of motor <'ell of ventral
horn passing; throu;;h wliite matter to lihxid capillary of the pia : hi. riij).,
hlood capillaries (1) in the jjray matter, (U) in the pia. with which the jiro-
toplasmic processes were sui)pos<'d to l)e connected or related : <l. r. f.. Ilhre
of dorsal root semliuK hnimdms into the amy matter to terminati' in the dif-
fu.se nerve network ; (iiilii'i vrU 'I'lijir II. cell in the tiniy matter, its nnicli-
hrantdu'd axis-cylinder process helpinf; to form the diffuse lu'twork ; -ip. <;.,
spinal ttan^tlion ; pir. .i. )'., peripheral seu.sor.v nerv<' fibre ; .v. .v., sensory sur-
face : r. III., vcduntar.v muscle innervated hy fibre of veiiiral root.
body, there arises a projection which corresponds to the sub-
st'fpuMit Jixis cylinder of a nerve fibre. The ]irotopliismic pro-
cesses do not develo]) till afterward and branch soon after their
appearance. The fibres of the dorstd roots of the s])inal nerves
represent processes of cells situiited in the spintd ganglia and
their terminations lie free inside the spinal cord. In the.se early
stages there is no anastomosis between the ditferent processes
of a single nerve element, nor couUl llis make out in the later
DRVHr.Oi'MKXT (»!•' TIIK NKUIloXK CONCKl'T.
r
(]cv('I<i|iniciitiil periods iiiiy cvidf'iK'O of tlic fusion of the pro-
ifsscs of one cell with those of another.* His, therefore, op-
posed the idea of ii diffuse network, iittrihutiiij; the uppeariinces
whii'h snj;«fested it to tiio existence of u most complex folt-
work (Xt'iirojii/rin) composed of the liner suhdivisions of the
processes of the nerve cells.
It wtis in 1SS7 that Mansen ])ul)lishe(l his coniprehensivo
iirti(do on the Htrueturo of the nervous system, t in which he
attempted to show that the axis-cylinder })roees8es of the mTve
cells are !na<le u}) of multiple tuhes of minute size. It is of
no litlhi Intercast that the cehthrated An^tic exjilorer at this
early j)eriod recioj^nized the lii{.(h importance of the discoveries
of (jolj^'i. On page 71 of his article he says :
" I think it is indeed also very stratige that neither Rawitz
nor Ilaller (nor most modern writers) are acfjuainted with the
excellent papers on the central nervous system of vcrtehrates
hy (iolgi. They (pioto a great many other and less important
writers, but they do not seem to know this eminent histologist
who, in my opinion, has really introduced a new epocdi in our
researches into the structure of the nervous system." >sansen
pictures distinctly, in Figs. Ill and 11:2 accompanying his re-
port, the bifurcation of the libres of the dorsal roots of the
spinal nerves.
The criticism Avliich appeared at this ])eriod frou) the ])en
of Forel, the celebrated Ziirich ])sychiatrist,]; is of extreme
vahu! from a historical standpoint. Well versed in the results
of pathological anatomy and experimental pathology, and ac-
((uainted with the earlier work of His, Forel, in a short essay,
distuissed the status of nein'o-histology at the time, including in
Ids criticism the results and hypotheses of (iolgi. He recog-
?uzed fully tlie importance of (Jolgi's objective fiiulings, but
* At the 011(1 of fin iirticlo. Ziir rroscliiflitc dcs niPiisclilir'lipn Rilckcn-
niiirkos, dated ISHfi, Ilis siiys : " Als festsleliciides I'riiicip vcrtrcte icli dahei
(Icn Satz : dass jede Xervenfaser aiis eiiier cin/ijjeii Zclle als Aiisliiiifcr her-
V()ru:('lit. TMese ist ilir jjenetisches. ilir nutritives und ilir fnnotioiielles Cen-
truni: alle andoren N'erliindunjjen der I'^iser sind entweder nur niittelharo
oder sie sind seciiiKliir entstanden."
+ Nansen. F. The Sirnctnn' and Coniljination f)f the ilistolojjieal FJc-
ments in the Central Nervous System. Hcrgens Museum .\arst)er(>tninjj for
1HH(!. Tkrgeii, 1887.
X Forel, A. Einige liirnanatoniisehe Hetraehtungen und Krtrehnisse.
Areli. f. I'sychiat. und Xervenkr., Merl., lid. xviii. 1887, S. ltJ:2-l'J8.
8
i
IS
TIIK NKU vol's SVSTKM.
h
witli pt'ciiliiir kcomicss of iMTfcption sifted out the facts from
(lie liypotlicscs. He I'litcrcd ii stroM<; protest upiiiist the net-
work theory and spoke for the niaintenaiiee of tlie individual-
ity of the nerve eh-jnents. Korel re(!o^'nized tlie iniporlance of
the "caprice " of the (iolj^i method in sta'tiinj,' an cU'ImcmI only
here and tliere as l)eariti;; u|miii the independence* of the nerve
units, Itut it is his utilization (»f tiie studies of secondary de^'en-
erations which makes liiH communication of the deepest si^niti-
cance. Me j)()inted out that not only does the distal end of a
divided motor lihre under<^'o rapid disintcfrnition after section
(Uallerian de<,'eJieration), l)ut tiuit also, in contradiction to the
d(»(!trinc of Waller, the proxinuil end underf^oes cellulipctal de-
j^oneration, though often much more slowly (von (ludden's law),
when the division of the lihre has occurred at the point of exit
of the motor nerve from the central system. Korel further em-
phasized the fact that when degeneration involves a tract of
nerve fihres it extends only us fur as the termination of the
tra(!t. If atrophy of nerve cells and nerve fihres occurs heyond
the termination of the tract, it is of a fundamentally different
character from that which aifects the tract under<foing typical
secondary (le<^eneration. Whereas in the latter process a raj)id
and complete disintefjration with uhsorption occurs, in the other
case there is, as a rule, only u diminution in the calibre of the
nerve fihres and a shrinkij\g in size of the nerve cells (so-culled
indirect atro})hy).
To illustrate this point, Korel, happily it would seem, chose
the experimental degenerations ])roduced by von (Judden and
von Monukow in the domain of the sensory conduction path
leudintr from the retina to tlu' cerebral cortex. Whereas if, on
the one hand, in an animal like the rabbit in which the decus-
sation of the fibres in the optic chiasm is almost total, one eye
be "^irpated, there results almost total degeneration of the cor-
r ng optic nerve, and of the opposite o])tic tract, together
considerable diminution in size of the lateral geniculate
ly, owing to the disuppi'arance not of its nerve cells but of the
gelatinous substance between the cells (consisting of the terminal
ramifications of the optic fibres which have entered it) ; on the
other hand, if the visual area of the cerebral cortex be extir-
pated, the lateral goiiculate body of the same side degenerates,
but in an entirely different way. In the latter instance it is not
the gelatinous substance which disappears, but the nerve cells
HiMMk
l»i:VKI.(H'MK\T OK TIIK NKfUoNK CO.s'CKPT.
19
tlu'm«i'lvi's vaniHii. The ()l)vi()iiH (It'durtioii In.ni the piitholoK-
icul (iiidiiij^H is that l»ct\vet'n tlif rctiiiu and tlie occipital cortex
ut least two nerve units arc interposed, one cxtendinj,' from the
retina to tiie optic centres ut the lm.se of the brain, and the
aecond from the latter centres to the (iortex of the eerehriim.
The limits of a f,Mveii (lef,'eneration under i.iitlioh.f^rical condi-
tions correspond in extent to those of the unit or units involved
in the lesion. Finally, for the lirst time do we find .stated clear-
ly in this arti<de the principle of contact as an explanation of
the correlations of the nerve cells and their ]»roce,sses within the
Kray matter, a prin<-iple the formulation of which has been
of consiilcrable inlluence in the development of neurological
knowled<;e, but one which, as we simll sec later, is not wholly
in uocord with the facts.
f
1
1
\ I
!■
I
■■■]
t
!.
I
I '
f^
,
CIIAITKK 11 r.
TlIK STlI)Ii;S OK KAMON Y (AJAL A M> OTMKISS WITH (!()L(!l's
Ml.TllOl) AND Wrni MODII'ICATIONS OK THAT M KTIIOD.
lleseart'lit's of Ujiiiu'iii y ('ajal — Di'iiinl of occiirrt'iico of aiinsloniust's iiiiion^
norvc (>lciiu'iits — 'I'he collati^nil imuiclit's of tlio axis-cylinder processes
— 'I'eiideiuty to external inurplioloyical iiiiiforinity aiiioiij;' the nerve
elements — Transit ion forms i)elween cells of Type I and cells of I'ype II
— The cells in sensory and motor rei,'ions — Studies of other investifjators.
TliK cojitfibiit'oiis of Ford iind His, well sii])i)ort(>d and
coiiviiiciiij,' as t'.cy were, did not, liowover, suilicc to (M"jidi(!ato
tlio older ideas of a retieidiiin from minds in \vlii<'li tlicy were
as firndy estahlislied as are most prejudices ntid ])re('on('eived
ideas taken in with motiier's mili<. To ajjpreciate discoveries
1)ased partly iii)()n patholoe^ical experience, I)iit lartfely upon
studies in Instojjenesis, a iield whose fruits had not yet at-
tained the aiipreciation they (h'served, a conservative niedicial
world re(piired, for its awakcninj,', inlliiences still more arous-
in<ij. I'iiese were soon forthcoming and from an unexpected
quarter.
If we may believe a ])optilar rumor, somotliing more than
ten years a.ij^o a younj^ doctor in S^tain, a conntry remarkalde
from a medical standpoint u}) to his titne for its barrenness in
orijjimil research, ap])iied for a position in micros(H)py, which
was refused him. His pride wounded keeuly, he ri-nouncod hi.s
social relations, ])urchased a small lilirary on histolojjfical sub-
je<'ts, ])aid special attention to certain tccduucal methods,
worked like a .'^lave at his sid)ject, and a decade later found
himself famous. Saidiago h'atuon y Cajal has left l?arcelona
behind him and is now professor at Madrid, has lectured before
inter!iational aud'icnces, and Iims W(>n the ailmiration atid respect
of the whole scientiii(^ world ; he is a nu'dical /
III 1110
rlrl. The
story, oven if it be not true, is certaiidy well invented. Besjiu-
ning with two articles in the year ISSS, oiu' ujxui the retina of
20
l)KVi:i,()l'MKNT OF TIIK NKl'lJONK CONCHl'T.
LU
liirds* 1111(1 Mic other upon the nerve fibres of the inoleeiilar
liiyi'r of tlie eereliellimi,! K'jiiik'hi y Cajal exliihited diiriiij^ the
next few years a most .istoiiisliiiii; iirodiietive activity, J wliieli,
jiid<,Mii;j: from the nature of liis articles in current journals, is
by no means yet exhausted.
A brii'f in(|uiiy into tlie contributions of Ivanion y Cajal can
not fail to make clear why tliey almost immediately attracti'd
close attention in widi'ly distant <|uarti'rs. Leavinjjjout of con-
sideration the immense mass of detailed discoveries with which
Kaiiu'in y Cajal has enriched the liner atiatoniy of the spinal
; ord and brain, the salient features of his work, those which
make i;; so si,i,Miilicaiit as re^^ards (»ur ])resent conce])t of the ele-
mentary structure, arc (I) the demonstration (apparently defi-
nite at the time) of the complete indejieiulenci' of at least the
majority of the nerve elements, the branches of the axis cylin-
ders formiiii; anastomoses lo more than those of the dendrites;
('■i) the appreciation of the widespread occurrence and signif-
icances of the lateral branches (collaterals) of the axis-cylinder
processes; and ()>) the demonstration of the striking uniformity
ill ifcneral stru(!ture of the majority of the nerve elements in all
parts despite multi])le minor morphological variations.
(iolgi, as 1 have said, had denied the existence of a network
made up of anastcmiosing protoplasmic ])rocossos, but helieved
in a ditVuse nerve reticulum composed of the united fibrils re-
sulting from the complicated subdivisions of the axis cylinders
of cells of 'Vy\w II and the lateral fibrils of the axis cylinders of
cells of Type I. The Spanish investigator emphatically denied
* IJaiiion yCiiJal.S. Kstrnctiini ili' la iu'tiiuMlc lasAvcs. l{c\ ista 'rriiii.
(Ic llisli)l(i^iu XdMiial, etc.. Nds. 1 y '2, Mayo y Apislo dc INHH, (^IikjIi'iI liy
von Ij('Ii1i(>ss(''I<.
•(■ Sdlirc las I'Mliras N'crvosias dc la ra])a Molecular del ('crcbclld. ivc-
visla Trim, ilc Hist., etc., .Xj^oslo, ISSH. (^)uoli'(l iiy voii Ii('iilii>ss(''k.
I 1 liavo rct'crt'iiccs Id no less than nine articles on tlic iicrvoiis systi'iii
licariiif? liis iiMinc, pulilisiicd duriiif,' llic year IHilO alone. It would o('cu|iy
too niucli space lo f,'ive here a coniplele list of his pulilicalioiis. ,\ii epilduie
of his views is lo be found in Les iidiivelles idces sur la slruelure du sys-
tenie nerveux clie/ I'lioninie el che/ les vertel)res. I"'rench by Azdulay, I'ai'is,
I Hot. and in the Croonian Lecture, La line si ructure (les ccnl I'cs lu'rveux,
I'roeeedinjjs of the iioyal Society, Ldndon, vol. Iv, lS!t4, pji. 4-f4-4(iH. 'i'his
lecture was delivered in French and published in the same lanjiiuii^e. ,\
brief but naccurate ab-lracl of it ill Kuf^lish was prinled in I he IJritish
Medical Journal, lHi)4, i, p. .")43.
■iH'
m
^j^'
22
TIIK NKllVorS SYSTEM.
M
, i
u
i. '
the t'xistenco of iiiiy such ditfuriu mTvti network. lie main-
tained that in tlus ccrobro-spiniil nervous system tlio axis-cylin-
der processes and tiieir lat-
eral hranclies, ])el()n<rin<f to
no nuitter wliat nerve <h'1I,
always run out to end fi'ee
within the <rray matter.*
They often enter into close
l)r()ximify to other nerve
cells and interlace with
their protoplasmic proces-
ses, but nowhere could any
(nidence, ])y means of the
method lie emi)loye(l, ho
found of actual union — the
interrelations of the nerve
elements depending entire-
ly upon contact or contij^u-
ity, not upon organii^ <ton-
nection. This was proved,
he believed, to be true not
only of end)ryonic struct-
ures, but also of the tissues
of the adult, so that the
neuro})ilem of His and the
contact priiici])le of Forel
met with full confirmation
in the reseandiesof Kamon
y Cajal.
The side fibrils discovered by (iolgi upon some of the axis-
cyliiuler processes were made by llamon y ("ajal an object of
special study. Particularly fortunate in this regard was his
application of the silver staining to the endjryonic; eord.f He
found that in embryo chicks after the fifth day of incubation
it was easy to stain many of the axis cylinders of the white
fasciculi, but was astonished to find coming off from each
* In his earlier publications Ratiion y Cajal made certain resiTvatioiis
and sjiuke of possible oxeeptions, but later liedenieil all anastomosis tx'tween
the pt'oeesses of nerve cells, thus p)ing t(jo far, as will he seen later.
t Kamon y ('ajal, S. Sur I'origine ct les ramlfleations des fibres ner-
veuses do la moelle embryonnaire. Anat. Anz., .femi (f8!)()), fJd. v, pp. S."), 111.
Fl(i. S. — r,i>ii},'ilii(liiial saKJUiil scctidn of
ilcii'sid l'iiiii<iihis of tlif spinal eiinl of a
cat lil'lcen (lays (lid. ( Method of (iolj;!. )
.1, lilii'cs (if dorsal Ciniiculi ; II. coUatciiil ;
('. jiroiip of (•ollatcrals niniiiiiK ventral
ward ; I), end ail)ori/:ition of some col
laterals in the nr.iy matter of the dorsiil
horn ; A,', axis cylinder of a nei've cell.
(.\fter i{am('(n y Cajal. )
DKVKLOPMENT OF THE NEURONE (CONCEPT.
23
fil)ro, witli ii slifflitly wcdgc-sliapi'd origin iit rigiit iiiiglorf or al-
most ut riglit iiiiglos, a coiisidorablo number of tine collateral
1)ranclios (Figs. 8 and U). These collateral branches jienetrated
deeply into the gray matter of the cord and terminated in free
cud arborizations among the nerve cells and their i)rotoplasmic
processes. The tine nerve plexus, described in tlu^ bibliography
as occurring about the ganglion cells, was attributed by Kamon
y ("iijal largely to the interlacing of great numbers of the fi])rils
constituting these end arborizations of tiie collaterals. Such
Fl(i. il. — Tninsvcrsc scctiiiu of the spinal ciml iit'a cliick ut tlif iiiiitli (lay "!' in-
('ul)ati()ii. (Mctliiul III" (iolKi.l II. lihns of dursal rcmt ; h, ciillatcrals I'idiii
the (Imsal r<i(it lihrcs ; ;/. ciiUatcnils fniiii tlic ventral Cuiiiciili ; h. cullattrals
licliiiuK til t'orin tlic ventral I'lanniissufe ; il, end ailimi/atiiins of enllaterals ;
o, i'i)lliiterals Kiiinj; to I'onn the ilorsal coTnniissnre. (ACtei' Kaini'iu y Cajal.)
• m
<-. ) 'I
collateral branches o(!cur in till the white ftiscituili, ;ind fur-
ther, they show a tolerably (lonstant disposition in all regions
of the vertebrate spintd cord.* On the ventral root fibres of
* As to the iiiittire of the colliiteriiis, Rtiinon y Ciijal says {op. cit., p. 90) :
" Que repn'seiiteiit cos librilles colliiliTules (pic nous vonoiis de nieiitionucr?
A iiotre avis, il s'a^it pi'ohiihleiiieiit dc libros do ('oniiexii)ii celliilaifo quo
tons les t lilies do la substance hlaiiclu^ envoieiit a la ijrisi; a (in ilo inetiro en
contact recjiproque dos corptiseles nervetix places rolativoineiit a de grandes
distances. Ij'alisonco do inyeline an niveau des contacts (corps des colliiles
et arhorisatiiiiis des collaterales) faeiliterait purticulieroineiit la coiuinuiiica-
tioii de rebraiileinent iierveii.'c."
tl I
24
THE NERVOUS SYSTEM.
i
; •
I. i;
1!^:
Fid. 10. — Scliciiiatic representation of
section of (lorsil finiiculns cut lon-
{{itudinall.v liiinillel to entrance of
(lorsil roots, (.\fter lianionyCa-
tlie (!hick iiiid tho calf he coulti
find no ('(dliitcrals, })iit conccrn-
iiifj; the lil)rt'.s of tlic (h)r,siil roots
the most interesting rehitions
came to li,ijht. In preparations
<)f tlie cord iiiid dorsal roots of
eliieks from the seventli to the
twelfth (liiy of incnhation he
showed that tlie tihre reprosent-
injj the centnd process of a cell
in the s])initl <fan<rlion runs
tlirouofii the dorsal root as far
as the surface of the cord, into
the substance of whicli it pene-
trates ol)li(|uely. Inside tlie
cord * the axis cylinder under-
goes a distinct V-shaped divi-
sion into two strong ternnnal
branclies, one ascending, the
other descenditig. both soon as-
suming a longitudiiiiil direction,
evidently constituents of the
dorsal fasciculi of the cord. Fine
collateral branchings could be
seen coming off not onlv from
the main axis cylinder, but also
jal.) .1. <lors;ii ro,.t ; N, wiiit.; sui.- fi.()m its two branches of division
stance : O, tira.V sul)stance ; r. cell
at different levels on their way
up or down the cord (P^ig. 10).
These passed forward through
or medial to the substantia gela-
tinosa of Rohindo to end, some
among the cells of the dorsjil
of jttray matter .sen.linK its axis-
cylinder itnicess ii|n\ar(l in dorsil
funiculus; />. another cell seudinn
an axis cylinder into the white
matter; tliis imicess hifurcates,
yiehlins an ascendiuj; and a de-
sceiidini; tihre; A", another cell
sendiii}; an axis cylinder down-
ward in the dorsal fnnicnlus: /. /•'.
and 'i', terminal arlinri/alioMs of
axis-cylinder pmctsses ; />', termi- homs, mailV of them iimoug the
nal arhiirizations in th<> firay mat- ,, » , i ' i i i »
t<'r of collaterals from the white celis ot tlie ventnd hom. As
sul..stance : a. .•ollatenil from one ^^ (^| tdtimatc fate of the US-
ol the divisions ol a dorsal mot
tihre; ft. collateral from the main cending and descending fibres
trunk of a dorsil mot tihre heforc ... , ,, ». i ■
its Y-shaped division. resulting from tiie 1 -siiiiped
* Uiirnon y C'ajal (Anut. Anz., 18i)f). Hd. v. p. 92) .says, " Dans Tepaisseur
(le la n'lrion dii cordon de Goll." This should probaljly read "cordon de
Burduch.
i'
m
KEVELOPMENT OF THE NEURONE C'oNCEl'T. •_>:>
division, "Runion y Ciijal rould not iit tlui time niiikc iiny dt'tinito
statcincnl.*
The great nund)ei's of niedullated ii])rps passing more or less
ill Imndlos from the (U)rsal fasciculi into the gray substance
had hcH'U generally re(M)gnized and could not indeed have very
well been overlooked, so proiiiinent a part of the ])i('ture do
they form in sections of the niedullated sjiinal (U)r(l stained by
Weigert's method {vide Fig. 11). The observers thought them
to be (1) niedullated axis cylinders passing from the cells of
B Z .
Klii. 11. — Cross sect idii of tlic cervical spinal cord ofa <'liil(l two years old. sliowiiiK
tiiediillaled collaterals passing i" from t lie dorsal t'asciciili and ruimiii;; for-
ward toward the ventral lionis. (After von KoUiker.l /, fasciculus fjiacilis
(tiolli); /)', faseiciihis cuncatus ( Biirdaclii ) ; /., fasciculus of l-issaiier.
till' gray matter into the wliite fasciculi, and {'i) fibres of the
dorsal roots or of the dorsal white fasciculi turning in to ter-
minate in the gniy matter. Uiimon y ("ajal proved that the
* Through a eoinbinali' of the results attained l)y Golgi's methnd, by
1 he iiielhotls i)f secondary detrcneration and Fleehsig's einbryologieal method,
we have now tolerably accurate ideas as to the course and destination of the
lilires of the dorsal while fasciculi of the cord, their relations to the gray
matter of the medulla spinalis and that of the medulla oblongata. Von
Lenhossek has made an extremely careful study of the various groups of
collaterals jiertaining to these fibres, and has given us in a monograiih (Der
feinere Ban des Nervensystems im Lichte nenester Forschungen. zweile
.\u(lage. Herlin, l.S!)5) a most interesting and reliable ri'siniK' of the facts at
present known about the tiner anatomy of the cord, iiududing the results of
his own brilliant researches upon the sjtinal cord of human beings. Kamon y
Cajal's treatise (ii'anatomie fine de la moelle e|)iniere ; Liefernng iv of Mabes'
Atlas der path. Histologic des Nervensystems, IJerlin, 18i)r)) may also be
consulted in this connection.
W
2<;
THE NEltVOUS SYSTEM.
I< i
majority of these >lo not n'])r('S('nt iiiiiiii iixi« cylinders iit nil,
l)iit are eollatenil hninciu'S, ii tiii(iiii<f wiiich has heeii coii-
iirnied over and over again hy snl)se({uent investigators in all
(iountries.* 'J'hey re])resont structures of enormous in'.portunije,
a large portion of them [RrjJv.rrolhitcnih'n of K(»llii\er) rei)re-
senting the most direct path of nerve communication between
the sensory surfaces of the body and the ventral horn cells gov-
erning the voluntary muscles. We tiiul in i\w sensory fibres,
with their subdivisions and <!ollaterals given oti at ditferent
levels of the cord and medulla, f the anatomical mechanism
conceriu'd in the simi)le and more complex reflexes, and ])rob-
ably in many of the instinctive reactions, and we have further,
as His says, not far to go to find the explanation of the well-
known fact that the same sensory impulses which })crmit
consciousness to be affected also account for the setting free
of rertexes.
Amid manifold variations in type, (iolgi had been struck
with the wonderful similarity of the nerve cells tlu'oughout
the whole of the central lu'rvous system. Ife had even, it will
be remend)ered, attempted to reduce all nerve cells to the two
types before mentioned, and from his studies regarding the
mode of distribution of cells of these types he had coiududed
that the first type of nerve cells belonged to the motor or
psycho-motor, the second type to the sensory or ])sy(tho-sensory
regions.| With the advent of Ford's critique and of Ramon y
hi! !
* Siune of tlio fil)n's of tlie dorsal roots cortuinly oiitci' ttio j^ray matter
l)of(jr(> umlorf^oiiig tlio V-slia[)i'il division; somi' infdiillal(>(l fibres [)ass from
tlie gray matter l)ack\vard (centrifugal fihi'cs of dorsal roots in the lower
vertehntti's, and fil)res of dorsal fasciculi whose cells of origin are sit ited
within the gi'ay matter of the cord).
f It was Ki'illiker who sliowed that the sensory cerebral nei'ves undergo
V-shaped division in almost exactly the same niauiier as do the sensory
sjiiual nerves.
X tiolgi, iu his arti(!lo entitled Anatomical Considerations regarding tho
Doctrine (jf Cerebral bocali/ation, in 1SS2 detailed the results of his studies
on the cortex, from which he coucliule(l that the cells of Type I and 'I'yjio
II were not separated from one another in the single convolutions, but wito
always asso<'iated with one another in all parts of the corttix, and that ac-
cordingly there were not only evidences against the strii^t separation > ■' tho
two main functions, movement and sensation, l)ut also positive grounds for
the assertion that in the dilferent cortiiNil zones there was no absolute sep-
aration of the sensory and motor functions, and that the anatomical seats of
these functions must to a certain degree bo intermingled. It is surprising
DKVKhOPMKNT oK TIIK NKrilONE ("ONCKPT.
•J 7
Ciijul's (lenioiistriitioiis the distinctioii.s hctwceii tlu'sct two tyj)c!S
lost, ill the main, tiio sigiiiiiciiiu'c which had bi't'ii attacdiod to
them. Tho only ossontial difference between cell Tyi)c I and
cell 'IVpc IF was shown to lie in tho length ai\d mode of hranch-
iiig of the axis cylinder. Whereas: that of the first type first
l''l<i. 12. — Cell rniiii tlic ;;i';i.v iimttcr of the siiiiial cord r('i)n"S('iitiii}; ;i I'onii iiittT-
nuMliiitf lii'twffii tliat of <iolj;i'-; cell 'r.v|>(' I ami llial of ( lolt;i's cell Typo II.
(.VftiT von liCnlioss('k. ) Tlic iiiiit'li-braiu'licd axis-c.vlinilcr process « can 1«!
followed into the fasciculus cinicatus of Hurdacli. /. r.
showed an end arborization at a considerable distance from the
cell, that of the second type broke np almost immediately after
leaving its (^ell of origin into its terminal filaments. While a
cell of Type I, through its long axis-cylinder ])rocess going
diret^tly over into a nerve fibre, is put into position to affect
other cells in widely distant domains,* the cells of Tyjie 11, the
axis-cylinder processes of which rarely, if ever, Uuive the gray
matter, are destined to influence other cells in the immediate
iieighliorhood. These latter in all probability do not always
act as servants of main conduction, but are to be looked upon
how near — cvt^ii with false premises — an approacli to actual relations can bo
Mrriv('(l at !
* Tho axis cylindors of sonic of the i)yrami(ial (^elLs of the I'crehral cortex
attain a length of nearly one metro.
;:4
2S
TIIK NKWVors SVSTKM.
if .;
as havinjj u di'tiiiite local funotioii, probably of no mean signifi-
cance* Tlicv occur in motor as well as in sensory areas, and
there is no j^roiind at all for attrihiitin<f to them, as (lol;jfi did,
aJi exclusively sensory function. Further eviden(;e has recently
heen fortlu^oming in that transitional forms between the cells
of Type I and those of Type II, the hypothetical existence of
which von Monalvow postulated, have actually been described.
Von KuUiker and von licnhossek, for example, have described
cells in the spinal cord (Fij!f. l'^) with axis cyliiulers which, in
addition to nnmifold branching, give off one main stem which
acts fpiite like the axis-cyliiuler ))rocess of a cell of Type I, and
recently von Hechterew f has referred to similar forms among
the stellate cells of the molecular layer of the cerebellum
(Fig. i:{).
It has become obvious, therefore, from the striking general
morphological agreement, that if we are to seek for data re-
garding the functional characteristics of nerve cells, we must
look for them elsewhere than simply in the external form
relations which they manifest; even the direction assumed
by an axis-cylinder process does not always permit a decision
as to the motor or sensory function of the cell to which it
belongs. While perhii])s the majority of sensory axones in
the central nervous system run upward and of motor axones
downward, there are plenty of exceptions to this, among them
the descending limbs of the bifurcated fibres of the dorsal
roots.
Kamon y Cajal's application of the (iolgi staining, almost of
the nature of a redis(;overy, attracted the most widespread at-
tention, and anatomists everywhere, casting other jirohlems
temporarily aside, set to work with the silver stain. In (ier-
* Tlicse cells liavc liccii (losifjiiatfd SvhuUzelh'n by von Moiiakow, in-
termi'i/iii/i' crZ/s by ScliiilVr, Vi'irinij/iini/.'izellen by von Bcchtcrow. The
term (issdrlttlinn cllx lias also boon ai)plie(l to them. The name Di'tirlra.r-
oiii'ii, ii\>\i\'u'i\ l)y von licnliossc'k, sciMiis to me most siiitaiiie as (list iiii^iiisli-
in;; tlicm from cells of Type 1 or Iiia.roni'n. Seliiifer's name jini/i'ction cell
lor the cell of 'I'ype I may easily lead to confusion, and T think is better
avoided. Von Monakow (Arch. f. Psychiat. n. Nervenkr.. Hd. xx. 1H80,
S. 7H1) seems to have been the first to rei^of^iii/.e the siirnilieance of Golgi's
cells of Type II as SrhnUzellen.
\ Von Hechterew. \V. Die fielire von den Xeiironen mid die Kntla-
dungslheorie. Neurol, ("entralbl., Leipz., IM. xv, 18!)(», S. nO; 10;{.
II
DEVELOI'MENT OF THE XErilONE CONCEPT.
29
many, von Ki'illikcM',* von Ii('nlioss(''k, Waldovcr, and K(lin<jor;
in Ik'lj^iiiin, van (k'liucliti'n ; in Swcdi-n, lit'tziiis; in Kn^land,
Schiifer and Andric/zcn ; in America, Ik-rkley and Stronj^, to
aay nothin;,' of a wliolo host of otlicr ijivostif^ators in this and
other countries, went hnsily to work with tlio osnio-hicliroinate
mixtnre and silver nitrate, and within a surprisinjfly siiort
period we have been supplied with information regarding the
Fig. V.i. — .\ tniiisitioiiiil furni, (i. lu'twci-ii (}oli;i's cell of Type T iind ccU of Typo,
II from tile iiiolcculiir layer of tlii' (■frclicllimi. ( After voii Heehlerew. ) TIu;
iinicli-l)r;uielie(l axis-cylinder iirocess c retains its identity for a eoiisiderahle
distance from tlie cell Imdy. The (U)res f. 7. uri^ axis-cylinder pn sses of
other neurones which are Kivin;; otf liran(dies in the neij;lihorhoo(l of the cell
(( and its protoplasmic processes.
form iind loctil reciprocal relations of the nerve units in the
most various portions of the (!erel)ro-spiual and .symi)athetic
nervous system. The views advanced by (^lolgi and Riimon y
♦Von Ktiilikcr visited Golfji in 1H87. and culli'd iitttMilion in Mmt year to the
ji^rcat si<j;nitic'ance of the Italian's observations (ef. Dit^ Untorsiichiingen von
(Jolf^i iihor den feineren Man dcs ('entralcn Nervensystcins. .\nat. An/.., Jena,
Hd. ii (ISST). Xo. 15. S. 4H()). i''rom litis Mine on lie lias Imsied liiniself ex-
tensively with tlie silver method, and has made contribntions of very liifjli
importance for the development of the netirone eoneept of the nervous
organs.
'M)
TIIK N'KIl VOLTS SYSTKM.
^t
("jijiil liiivc been most tliorouf^'lily sifted, have undergone mani-
fold coiifirmutioii iuid certain iiccessary correct ion.s, until ut
present we are in a position to form a concept of the orj^anizu-
tion of the nervous system, clearer, shar])er, simj)U'r, and more
pleasing? than coidd have been even imagined by the most
fanciful dreamer of two decades ago.
1
niAPTKU IV.
TllK VITAF, STAINlN(i OK TIIK NKHVK KIJ-M KNTS.
The iiictliod of vital sliiiiiiiig iiilruiliici'ii by lOliilicli — 'I'lic results afTonlod
by it.
Satisfa( TOKY and fonviiiciiif; us wore tliosc n'stilts with
the silver inctliod (ihtaiiicd l)V all who tried for them, the new
ideas received important support, indeed, were in part estah
lished, throii<j:h another metliod invented hy one wlio fairly
deserves the name of " eliemical magician " — Khrlich, of Herlin.
'I\) have worked out from a chemical hasis and lahoratorv ex-
periment a method for the ditTerential color iinalysis of the
leucocytes which lias revolutionized our ideas of the hlood and
elevated hseniatoloffy almost to a special branch of medical
science; to have inau<;iirated with e.\i)erimeiits witli ricin iind
ahrin a new era in investijjations on immtinity and antitoxine
therapy; to have illustriited hy the methods of staining living
nerve cells and their processes with methylene blue the possi-
bilities of an ex])erimental pharmacology of whitdi we could
scarcely have dared hojie, would surely have been enough in days
less liberal than ours to have convicted their author of witch-
craft and of being a menace to the common weal. Khrlich
realized that the ordinary histological methods of fixing and
subsequent staining, though yielding important anatomical con-
clusions regarding the structure of the tissues, fail to give us
very exact information regarding the properties of the living
cells. Concerning pharmacology, it is his idea that a definite
toxic substance can aifect only those elements primarily to which
it actually arrives and by which it is taken u]) in a specific man-
ner. If such be the case, the determination of the laws govern-
ing the distribution of the substance are of prime importance,
and the physiological action of the drug should be brought
into accord with these.* On account of our poverty in miisro-
* Klirlinli, P. llobcr dio Slothylcnblaiiredction dor lobenden Nerveii-
substauz. Deutsche lued. W^ohuschr., Herl., 1886, Hd. xii, S. 40-52.
31
i!
I'i I
THK NKItVOUS SYSTKM.
V'lictiiiciil reactions it was impossible for liitii at tlie time to px-
lierimeiit satisfactorily in this way with tlic alkaloi<is, l)ut with
certain aniline dyes the prol.li jn conld nH)re easily ho a|»-
])r(>ache(l. Kxperimentin;^' alom; Ihtso lines, Khrlich found
that hy injection iii/ni rifiuii of ii Holittion of methylene hi no
dissolved in salt, solntion into the hlood-vessels of an animal,
the axis cylinders of many of the nerve lihres (Ki^. 11) as well
1^ I i
^^^?*Z
Fui. 14. — Nerve (ilires I'riim a (Vok injected willi metliylene liliie. (MetlKid of
I'^lii'lieli. ) 'Pile axis eylinders iU'i' .stained diiik liine. In plaees tiie in,v<'liii
slieall
1 IS soniewliat stained
Me nixies (i
r lianvier and the <li visions of tlie
tihresat siinie of tlie nodes are well shown. (.M'ter von Koiliker. )
as nnnierous (particiilarly sensory) nerve endings (Fig. 15) were
stained after a time, when the animal was killed and the tissues
exposed to the air, of an intense blue color, the other tissue
elements remaining little or not at all affected. The staitiing
was of only short duration, the color gradually fading, and with
■k :
DKVKI.OI'MRNT OF TIIK NKrUONK CONCKI'T.
33
the ftidiii;;, as a rule, more or loss (litTu«e sluiiiiug of tlie other
tisHiU'rt occiirrt'd.
Klirlicli made some inlrrcstin}^ coiiiparalivc tests with dyes
close
lied to nietliyleiie hliie ill order to olitain if possible
ulieiiiieul explanation of the stainiii;^. Tims, lie found that while
fu
(Misiii, niethv
vi<»let,
and sadVaiiiii, which con-
tain no sulphur, would
not Htain the nerves, thio-
iiin and diinethvltliioiiin
as we
as nit
thvl
eiie vio-
let yielded a n'aetion simi-
lar to that ohtaiiH'd with
nietiiyleiie blue, so that
the jiresenco of one basic
^roup (of one anmionium
residue) in the nioleeulo
(instead of two, as in
inethyleiie blue) aiipeartMl
to siitlice for the reaction.
He further experimented
with the expensive sul-
l)lion of methylene blue
( Mcflii/lciKiziir) and found
that he could obtain with
it tlie nerve staininjj:, so Km. IT).— Sensory nerve fiidiii}; stainiMl witli
iiK'tliyli'iic Mile ( inetluxl of ICIirlicii ) in tliu
cxoriinliiini of (lie left auricle of a fjniy ii»t.
(.\fU'r Sniiniow. )
that it appears to lie a mat-
ter of indilVereiice wli(>lher
the sulphur in the mole-
cule exists as a pheiiylsiilpiiide oi- as a )/iienylsiilphoii. Finally, he
made tests with IhiidsclieidltM-'s orveii i Diinrthj/lplicii i/h'iujriiii),
which dilVers from methylene blue only in Iackiii<f sulphur. This
substance, which i.s distinctly poisonous, will not stain the nerves,
so that Ehrlich con(dudes that it is the (Milrance of sulpliur into tlu^
nioleculi! which d<'termines the nerve coloriiiii'. althouji'h li(^ re-
serves his judjjment as to the exact role ])layed by this element.
The conditions in the nerve structures essential to the methylene-
blue V(>a('tioii he thoufrht were (1) oxyji'en-.saturation ; (2) alkalinity.
Whether or not he still holds to these ideas expre.s.sed in l.S,S('>, J am
una
hie t(
) Si
ly-
It was .soon (U'monstrated by Arnstein that iiijeiition infra
vitam was unnecessary for tlie reaction, he having shown that
as long as the tissues remained alive injection into the dead
4
S (
1 '
t!
34 THE NERVOUS SYSTEM.
aiiimul gave results etiually jjood. Mayer asserts that even
several days after death the reaction is sometimes ohtainahle,
and comhats the uk'H of a " vital " stainintj. Certain it is that
sections of tissue cut with a Valentin's knife soon after removal
from the hody and laid in a weak solution of the dye, stain
beautifully. This fact I can assert from my own exiierience
with human as well as with animal tissues.
One serious objection to the methylene-blue method was the
transiency of the staining. Attempts were made to overcome
this, Pal using iodide of potassium, Smirnow iodine and iodid'ft
of potassium, I)ogi( , an a(|ue()us solution of ammonium picrate,
Mayer ami Hetzius ammonium ])icratc ami glycerin as a fixing
agent, but no one of these methods was entirely satisfactory,*
and the preparation of thin sections of the stained and imper-
fectly fixed tissues remained an impossibility. Through the
fortunate introduction of a fixing agent, which we owe to
Bethe,f this difficulty has been almost entirely overcome, and
* A very j^ood opilomo of tlie work (lone with the method up to 1891 is
to be found in the eolleetive review by 11. Riese in tlie Centrulbi. f. ullg.
Path. u. imlli. Aniit., .lena, Bd. ii (1891). S. 8:56-848.
f Bethe. A. .Studien iil)er das Contraliiervensystem von Carriniin JI(fti(i-'i
nebst Anguben iiber ein neues Verfiihren der Melhylenblaufixation. Airh.
f. niikr. .\iiat., Monn. 1894-5, Bd. xliv. S. .579-622.
The method depends upon eonverting the s<duble methylene-blue hydro-
chloride used in staining into an insoluble molybdate eondiination. For
vertebrate tissues the following mixture may be recommended :
Ammonium nu)lyb(late 1 grm. ;
Distilled water 10 c. c;
Jlydrogen peroxide 1 e. (t. ;
Hydrochloric acid, ('. P 1 gtt.
For invertebrate tissues the following is emjiloyed :
Ammonium molybdate 1 grm. ;
Distilled water 10 c. c. ;
Hydrogen peroxide 0.5 c. c.
The solutions should in eacii instance be freshly prepared. Tlie tissues
should be immersed in the fluid (well cooled) at the acme of the staining,
and kept in the ice box for from two to five hours. They are then left at
the room temperature for a few hours, washed for half an hour in distilled
water, dehydrated (juickly in cold alcohol, and imbedded by means of
repealed xylol clearing (to remove all alcohol) in balsam. After-staining
with alum-cochineal is often helpful for contrast. In a more recent article,
entitled Fine neue Methode der Methylenblaufixation. Anat. .\nz., .lena,
Hd. xii, 1896, S. 4;{8-446. Bethe has suggested further modifications of the
method, useful for various special tissues.
DKVELOPMEI^T UF THE NErilONE CONCEPT. 35
■>i
ill
Fi<i. 1(>. — l.vW lialf (if liniiii ^'iuiKlinn of S,-iri.i dnryslcolnf witli tlic ncrvt's
couiic'ti'd witli it si'cii fnm; tlic tlnrsil siirfiUT. MctliylciU'-liliic staiiiiiiff,
lixation by Hitlic's inctlKid. ( After (i. Kctziiis, ISlHi. taken I'liiiii I{aiil)er's
Aniitdmii' (ks Mruxrliiii. 5. Aiill., 15(1. ii. S. S5ti. ) <;, anterior f,M"<iiil» "f Kanulion
cells; (/'•', latenil Kroup <if ^lanjilion cells; ;/', posterior >;>''>"P "f Kanjtlioii
cells; sii, ))ipiilar cells of sensory type, the periiilienil processes of which k<>
t«) a spot in the skin (.•<), to end there: jir. anterior aKKi'eKation of coarse
Knmnles; iiii. anteniia-ni'rve tilires ; ((.antenna; m. denilritically liranclietl
nerve lihre (niuscnli rve ) ; h, nerve liranches. liraiicliinK of coaisely
fininular lilires ; pii. nerves to pal|> ; <■, coimnissural hranches of nenr.il cord
fjoinn to siilHcsophaKeal xanjjlion ; iiii, pij^ineiited eyes.
i!li
36
TiiK NKRvors svstp:m.
Ii
n
>
it is now possilHc not only to fix heautifnlly tlio structures at
tlie height of the staining, V\^. lO, hut also to inihed the tis-
sues thus fixed in puniftin, whicli permits of the preparation
of sections of any desired tliiuuess and so to counter-staining
by means of suitable dyes, for example, alum-cochineal.*
I have laid some stress upon the introduction of the methy-
lene-blue method, but not more, perha])s, than its im])ortan(^e
warrants. As von Lenhossek has said, until the introduction
of the (iolgi stain, no one probably had seen a lu'rve cell with
all its processes — a complete lu'rve uiut in its totality. But
even with the (iolgi stain not every element impregmited can
be followed throughout its whole extent. Iiuleed, it is ])erhaps
the rule tiiat where the medullary sheath begins the silver
impregmition of the axis-cylinder ju'ocess ceases. The stain-
ing of lu'rvi' eiulings in adult structures with the (iolgi
method, even with double and tri])le impregnations, succeeds
only rarely. Hut just here lies the great value of Khrlich's
method. With a little care and a good sample of inethyh-ne
blue the nerve eiulings and the axis cylinders of nu'didlated
fibres, with which they are continuous, can l)e stained in a way
far surpassing in constancy and completeness tlie best results
of the uncertain gold chloride ]irocedure. Already most iiii-
l)ortaiit contributions have been made with this method I)y
Ehrlich, Dogiel, Retzius, Si.iiruow, Rauinu y Cajal, von Len-
hossek, Symonowicz, Iluber, Bethe, aiul others, and it may
safely l)e predicted that with the recent improvements it will
be much more widely and successfully ap[)lied. That the
method is also applicable to the study of pathological tissues
removi'd by operation from hiinian beings has been shown by
*Wilh liiivilowsky's modinciitioii of I'^lirlicli's iiu'tliod. t(>,i,a'tlii'r with
|{ftlH'"s fixing pniciMlmv. I lia\(> Ixrii iil)li' to (Iciiioiisti-iilc iicrvc ('iiiliii;,'s in
liuiiian 1111(1 animal tissues in a inaniu'i- ciuiri'lv siiiicrsciliiiiif any otlior
mctliod known to inc. Tlii' comparison of tiic uradnal aiipcarancc of
structure after structure ami of detail after detail in the tissue durinj?
tlio stainiiiix to tlie development of a pliotojjraphic lU'Siitive. an illustration
emiiloyeil i)y Lavdowsky, is very apt. If the stain l)e pushe(l too far the
picture l)ec()nu\s clouded, owinj; to difTuse staininij of the other tissues with
tlip l)lne — it lias been "overdeveloped." The methods of vital injection of
methylene lilue used at Wood's lloll. Mass., hav(> htMMi descrilie(l hy Morill,
A. 1)., .\iner. Naturalist, vol. xxx. ISIHI, |)p. ,s,")7-S.")!). Ilulier has de.scrilied
the methods he employs in the Journal of Afipliod Micro.scopy, Rochester,
vol. i, IS'JM, pp. (i4^(57.
Ill
DEVELOPiMENT OP THE NEURONE C'ONCEl'T.
37
the resejirches of Yonnj?, in wliich by nioiins of it ho has hoen
iihlo to (k'nioiistnitc the jn'i'soiicc of m-rvos in certain tumors.*
The results liitherto attained with Khrlich's inetliods have
coniirined and ehi])orated tiu)se of the (iol^i methods, except,
perhai)s, in one particuhir. Some observers, notably Dojfiel,
the distintfuished Russian histolo<:jist, have inaintaiiu'd that in
the metiiylene-blue specimens an aiuistoinosis of the proto-
plasmic processes of one and of neighborinjjf nerve cells can
be demonstrated. Indeed, if his illustrations represent the
actual conditions, it becomes necessary to somewhat modify
the ideas re<jarding the relations of nerve cells fouiuled on
observations made with (^olgi's method, for he has pictured
not only the anastomosis in the retina of the dendrites of the
nerve cells, but also a network formed by the union of axis-
cylinder processes as well as the orij^in of nerve fibres from axis-
cylinder networks and from networks of dendrites. Masius f
also maintains that the dendritic prixH'sses anastomose with
one another. This view, at first thou<jjht apt)arently inimical
to the doctriiu^ of the morphological and ])hysiological inde-
pendence of the nerve units, has been stoutly denied by Ramon
y Cajal, von Lenhossek, and others, who have studied s})e('imens
staiiu'd both with (iolgi's and Khrlich's nu'thod, aiul it has
been subjected to an especial searching? criticism recently by
Houin. He denies the existence of anastomoses amonji the
retinal elements, except the braiu'hiutrs of the cells which
possess no axis-cylinder processes. 1 have myself, in a consid-
erable experience with specimens stained by the methylene-
blue method, been convinced that many of the a))pearances
which closely resemble anastonn)sis, especially in s])ecimen8
stained in bulk or in small i)ieces and fix'd by Dotriel's method,
are really ojttical illusions, siiu'e afttu' lonj; and tedious search
with oil-immersion lenses in paraftin sections of methylene-blue
preparations, fixed by Hethe's method, I have seldom been able
to fiiul any evidence of definite anastomosis. That anastomo-
ses actually do occasiomiUy 0('<nir can not, however, be longer
* Young, II. H. Oil Ihi' Pii'scnci' dl" XiTves in 'I'miKirs and of dtlirr
Slrufturi's in tliciii as Ki'vcalcd liy a Mollification ot' Kiirlirii's Motliod of
"Vital Staining" vith Mctliylcne Hiuo. .Imiriial of Kx|>('riiniMilal Medi-
cine, N. Y., IS!)?, vol. ii. No. {. I.]). 1-12.
t Masius. Jean. Reclicrciies iiistologicjues sur le systunie ncrveux cen-
tral. Arch, de biol., (iand, tome xii. 1M!(2. pp. l.Tl-Ki?.
88
THE NERVOUS SYSTEM.
F t i
doubtod ; for not only liuve thoy been seen ])y investigiitors
working witli tlie methylene-bkie method, l)ut Tartuferi and
others have found them in tissues inii)rognated by the chrome-
silver procedure. The work of Behi Haller, (iocppert, and
Edinger speaks also for the occurrence now and tlien of aiuis-
tomoses even of a coarser sort between the processes of neigh-
boring units. The much-used simile, however, that the i)ro-
cesses (and their divisions) of nerve cells maintain, in the vast
majority of instances, tlieir identity throughout, interlacing
perhaps with one another or with similar processes from other
nerve cells, just as the branches of the trees iii a dense forest
may intermingle but remain indcpetident of one another, the
nerve elements being as separate and as inde];endent as the
trees and their branches aiul leaves, has iipi)art.iily, (if h'ltsf so
far (IS fin/ji'i/iniic f issues arc coHccrncd^ had its complete ana-
tomical justification. Hhould occasional anastomoses between
the processes of nerve cells be even proved to occur, or should
it be true, as seems likely from the Avork of Held, Apathy, and
Bethe {vide infra)., that in adult life reciprocal relations exist
of a far more intimate sort tiian those that obtain in the em-
bryo, the general validity of the doctrine of the individuality
of the neurones would not be affected.
u
f.
¥
'i!i
CHAPTER V.
WW
THE TRUM "XEUROXE" AXI) THE NEUROXR COXCEPTION.
Waldeyer's review, in 1891, of the newer iuvostif,'ations — The term noirmii'
applied to the whole nerve unit — The neurone conception of the nerv.
ous system.
In' ISni Wtildeyer did great service to the new doctrine by
bringing together within a brief compass and in a clear and
convincing manner the results up to that time attained, com-
paring the experiments of the different investigators with one
another and submitting all to his keen and critical judgment.
His article * perliaps has done more than any other single
publication to make generally popular the doctrine of the in-
dividuality of the nerve elements for other reasons, but more
especially from the fact that — and this is a point upon wliich
von Lenhossek lays emphasis — besides his i lear presentation
of the established discoveries lie introduced a term for the
histological unit in the nervous system (including the whole
element — cell body, protoplasmic processes, axis-cylinder pro-
cesses, end arborization, and collaterals), dubbing it euphoni-
ously in (ierman Xciirnn (Greek, o vevpoW; English, iwnrone), a
term which has been almost universally adopted by amitoinists,
physiologists, pathologists, and clinicians in various countries.
Objections to the use of the word neurone as a designation for
the nerve unit have been offered by KoUiker, Schiifer, and
others. It is, however, so much more convenient a term than
any other which has so far been suggested, and, moreover, has
already entered so thoroughly into common usage, jiermeating
the bibliography of all specialties, that I think it must be
accepted ; if so, the use of the term " neuron " as a name for
the axis-cylinder process, as advocated by Schiifer in his admi-
rable essay The Xerve Cell Considered as the Basis of Neu-
rology,! is to be deprecated, and more particularly because a
* Waldeyer, W. Op. cit.
f Schiifer, E. A. Brain, Loiul., vol. xvi, 1893, pp. 134-169.
39
40
THE NEIIVOUS SYSTEM.
r I
I
il
i
tow tlistiiifjuishod toacliers huve been induced to continue the
use of tlie term in this wuy, thus leiidin<j iit times to consider-
able confusion. Since tiie word " neuron " has l)een emph>yed
by Schiifer to meiin tlie axis cylinder (axone or neurite) and by
Wilder to indicate the central nervous axis, and since the ori-
gin of the one term is the (Jreek vtvpov and the orifj^in of tliat
suggested l)y Waldeyer is the (Ireek vcvpwr, the (lesiral)ility of
spelling the latter in Knglisii " neurone," and of pronouncing
it neurone, is all tlie more obvious.* In the accompanying
illustration (Fig. 17) a typical example of a lower motor neu-
rone is shown in diagram. The cell body with all its pro-
cesses, including that extcjiding to the mugcle fibres, makes up
the total mass of one neuroiu'.
Enough has been said, 1 hope, to make clear what is meant
by the " neurone concept " of the nervous system. To sum it
up in a few words : The nervous system, aside from its neu-
roglia, ependymul cells, blood-vessels, and lymphatics, consists
of an eiu)rm()us number of individual elements or neurones.
Each neurone in its entirety represents a single body cell.
These units are at first eiifireli/ (if protoplasmic bridge^" be
excepted) and continue throughout life relalii'i'ly to be mor-
* Kollikor (lliui(ll)uch di-r ({ewcbelohre dcs Mciisclien. 1893, Bd. ii, S. 2)
states his ohjcctioii as follows: "Das Wort Xeiirnn^Ni'iiroiteii. das j^iit
kliiiyt, kaiiii spnioliiich niclit f;;obrauclit werdoii, wie voi'fjcsclilagoii wurde,
denn cs bedeutet eincii Saiiiinel|>unkt vieler Xeiiren oder Nerven. Von den
Worteii Neiirodoiiib'cii uiid NiMirodciKb-idicii ist das letztere. obschon liiii^'cr.
als rt'bersetzung von Nervenbiiiiinclifii docli viclluiclit oiitsprccluMidur."
The adoption, however, of the better sounding word is in this instance easily
intelligible, and, moreover, is not without many a jireeedent, as the phi-
lologist must sorrowfully gi-ant. In the present case, however. Professor
B. L. Gildersleeve, of the Johns Hopkins University, informs me that
Kolliker's objection to vtvpiau will not hold, as it would apjily e.(|ually well
to irapQfviiiv. which means "Ihe house of the vii-gin." Wliile the s])i'lling
neurone is not pleasing, for tiiat matter neither are the spellings anode
and rat/tude, which, after the analogy of mef/iod, should be spelled anod
and caf/iod, but, under the circumstances, in order to anglicize Waldeyer's
term, tlie use of the word and spelling neurone seems, as Professor (Jilder-
sleeve says, to be inevitable. (\f. Barker, \i. V. Concerning Neurological
Nomenclature. .Johns Hopkins Hospital Bidlelin, Bait.. 1S9(), vol. vii.
I>. 200. Frank Baker, of Washington (New York ;\Iedical .lournal. vol.
Ixiii (1800). p. ;5T;{: and in I'roe. Ass. Am. Anat., 18!l.'). Wasli., 18!J(). vol.
viii, pp. 40-45), has suggested the term nenre, corres|)onding to IJauber's
neura, for the nerve unit, a nomenclature which has received the support
of C. S. Minot.
DEVELOPMEXT OF THE NEURONE CONCEl'T.
41
FKi. 17. — Sclicmc 111' liiwcr iiiotdr iicuroiu'. Tlic iiKitor cell l)ii(ly. tciK<'tlii'r witli
mII its |inptcp|ilasiiiic pnM'csscs, its a.\is-cyliii<lcr iinxcss, side lil)i'ils, or cul-
liitcrals, and fiid raiiiilicatidiis. rc|)nsciit parts nf a single ('cli iir ucnriiiif.
II. Ii., axoiu'-liilliick devoid of Nissi l)odiis. and sliowiiijr tilprillatiiiii ; ii.r..
axis cylinder or axoue. This |iro('ess. near the cell Ixidy, licrnines surnmnded
hy myelin, ni.. and a eellnlar sheath, the nc iirih'ninia. liu' I 1 1 ler not heins iin
intef;i~al part of the neurone: <•.. eytoidasni showin;; Nissl liodiesand lif;liter
fjround substance: (/.. prololilasniie proces.ses (dendrites) contaiuinj; Nissl
bodies: "., nucleus: ;('.. nucholus: ti. I!., node of li;iiivier : s. /., side lihril ;
11. itf II., iniclens <if neurilemma sheath ; ^7.. motoi end plate or teloden-
dritni ; («'., striped muscle liliri' ; ,s. /,., sefjinentation of Lanterinann.
1
1
■
•* 1
i !■
ft' 1
42
TIIK NKHVOUS SYSTKM.
pholofficiilly, iiiid in part, at least, physiologically, indopendent
of one another.
Ther(( is no evidence of the existence of a diffuse nerve net-
work either in the sense in which von (Jerlacii or in that in
which (iol<,'i nsed the term, thouf^h sliould it he forthcomin<r,
it would not, and Waldeyer stated this in his article, interfere
with the neurone conception. The axis cylinder of every nerve
fibre, just as much as every protoplasmic! jjrocess, is an integral
part of a neurone, and has an organic connection somewhere
with a nerve cell. Nerve conduction paths may, and probably
uSiially do, in higher animals at least, involve more than one
neurone, the neurones l)elng, as it were, superimposed upon
one another to make simple or more complex neurone chains
or chains of neurone groujjs, one individual neurone through
its various processes being hi a position to be affected by and
in turn to affect several or many other neurones. Notwith-
standing almost infinite minor variations in form, the neurones
in the most different parts of the nervous system present sur-
prisingly similar genei'al external morphological characteristics.
The Jierve life of the individual, including all his reflex, in-
stinctive, and volitional activities, is tiie sum total of the life
of his milliard of neurones.*
* Ac'conliiij:^ to tlif I'stimiitiinis of Mi-yiu'i'l, the cortex ot tliu curehral
lieinis[''ic'res alone contains twelve hundred millions of ganglion cells. Don-
aldson (The (irowth of the Mrain. a Study of the Nervous System in Kela-
tioM to Fiducation. 1'2mio, London. IS!)?, p. 1.10) states that for the total num-
ber of nerve i-ells in the central nervous system three thousand millions is a
moderate estimate.
It may be recalled that (". I'^rai'cke (Die menschliche Zelle, !iei|iz.. bS!)l,
p. 27) has estimated the total nuinljer of cells, leaving out the I'ed blood-
eorjiuscles, in an adult human body to be about four billions (li.DOO billions).
The most accurate estimates of the total number of red iilood-corpuscles
at our command make the number about twenty-two billions and a half,
making a total of twenty-six billions and a half (26.r)00,()()0.00(),000) of body
cells. Donaldson's estimate for the nerve cells would, therefore, make them
represent one nine-thousaiulth of the total number of cells, exclusive of
the red iilood-corpuscles. an estimate which ])robably falls below rather than
al)ove the truth. All such calculations are necessarily extremely crude, but
atford opportunity for interesting study.
•M
JJILUIX I J
■-ft"'
niAiTER vr.
TIIK HK.VinX(i OF KKSKAUnrRS SINCK ISni UPON' THK
VALIDITY OK TIIK XKUROXE DOCTRINE.
The ri'liiit)ilily of tlic data upon which the neurone dootrino was founded —
The cell doctrine — ("onfirniation of the \vori< of His — Study of (h'i,'('n-
erations — Ucscarches with the inclhod of Marclii and witli the nictliod
of Xissl — Anastomosis of chondrites — Studies of Held upon crjucresceneo
— ("oiitributions of Ap.'itiiy.
It must now ])e tisked (1) In how fiif, in the seven years
wliich liiive elapsod siiico the ncuroiu' conception was distinctly
fornuihited, choosin<; Jirhitnirily the article of Waldeyer as th"
date of this, have the data upon wliich it was hased heen
found to be reliable? and {"i) Can all the results of researches
which have led to the discovery of new facts since that time be
brought into accord with the tu'uroiu' doctrine?*
It has been seen from what has preceded that the founda-
tion of the neurone doctrine is (|uadriiple : (1) The a priori
probability that the nervous system agrees with other parts of
the body in being a cellular system; (•?) the proof that in the
embryo the nerve cells exist as independent units, many of
which are capal)lc of wandering for considerable distances from
the site of their origin; (:}) the fact that the nutrition of the
nerve cells is most easily explicable from the standi)oint of a
doctrine which looks upon the nervous system as made up of
units, which are not oidy anatomical but also physiological,
since in pathological degeiuTative processes atfecting a given
unit or set of units, degeneration of a given type extends only
* Cf. Barker, L. F. On the Validity of tlie Neurone Doctrine. Ainer.
J. Insan., Bait., IHDS-'O. vol. Iv. pp. Sl-4!). Three American reviews of
the neunuK! doctrine may ho referred to by the reader — one by A. <). J.
Kelly. The Xeuron. I'niv. M. Mag., Phila.. WM-1. vol. ix, i)p. 27(5-29:5 ;
the second by D. I. Wolfstein, The Histological Basis of the Neurone
Theory, Cincin. Tjaiicet-flinic. n. s.. vol. xxxix, 18!)T. pp. nfi.l-.'iT!) : the third
by P. A. Fish, The Nerve VoU as a Unit. J. ("onip. Neurol., (Jranville, 1898,
vol. viii, pp. 99-112.
43
T ■' >
44
TIIK NKHVOUS SYSTKM.
!|
witliiii till' limits of tlmt iniit or Hct of units, any (Ic^ciioriition
of other units hcin*; of an entirely ditferent nature, atul when
reseinhiin;^ the former oeeiirrin;,' much more slowly ; and (4)
tlio liist()lo<;i('al (lemonstriitiou of the fa(;t that, for reiisouH as
yet too s\il)tle for aiuilysis, sometimes one unit, sonietinu's an-
other, may he picked out hy a particidar method of staininj,' or
imprejfiiatioii and l)rou^dit excjuisitely into view, others near hy
renuiinini,' only j)artially staiiu'd or entirely unaffected. In ad-
dition, the doctrine ajjrees well with all the known facts discov-
ered by Kdin;i;er, Ilerrick, and others in the field of compara-
tive anatomy.
Have these data been proved to be unreliable?' With regard
to the cell doctrine it may be said to be now universally held,
although it is true tlmt it does not explain all known fa<'ts, and
that here and there a distinguished biologist draws attention to
its " ina(le(|uacy." * Thi' end)ryol()gical researches of llis con-
ceriung the lu'uroblasts have been manifoldly contirmed by his
own and by other methods. Not until we c(mie to the studies of
degeneration inside the nervous system do we find any ajipear-
ance of discre])ancy. The docstrines of von (Judden and von
Monakow, on the whole, however, still hohl. Lesion of a given
set of neurones causes degeneration of the tyjjical and gener-
ally recognized sort (that revealed by Weigert's method) only
within the domains of that set. If large numbers of lu'urones
belonging to a given system degeiu'rate and are absorbed, there
may be, it is true, after the la})si' of a very long time, jmssibly
total atrophy with absorption in neurones of another order (as
pro])ably occurred in the case reported by Flechsig and Iloesel,
in which the corticopetal lU'urones of the general sensory path
had been injured by a lesion involving the central gyri, aiul
after many years many of the Jieuroiu's, the axotu's of which go
to nuike uj) the internal arcuate fibres of the medulla oblon-
gata and the fibres of the lemniscus medialis, had entirely disap-
jH'ared). But, as a rule, the tertiary change is one of shrinking
and dimiiiution of the calibre of the medullated fibres rather
f '
f I
* Cf. Whifmaii. ('. <». Tlio limdcqimcy of tlic Cell Theory of Devi'lojy-
mcnt. Wood's IIoll Hioloiiiciil liccliircs, 18!):! ; also in .1. Mor|)liol.. Host.,
vol. viii. 18!)!!, pp. (i:!!)-(i.')S ; aiul Scd^rwick, A., On tiic liiadtMjiiacy of tlic
Cellular Theory of Development, and on the Early Development of Nerves,
particMdarly of tlie Third Xerve and of the Sympathetic in l^lasmobranchii.
(^uart. .1. Mier. Sc, ivonil., vol. xxxvii, 1H!)4-T), pp. 8T-101,
li
It
DKVKIiOI'MKNT OF TIIK NKUKONK CONCKI'T,
45
tliaii ('((iiiplctc (liHiiitc^rriition and absorption (as tlic condition
in wliicii the liracliiuni conjnnctivnin is ordinarily found after
extt'nsivi' diseaso of one cerebral heniisplicrc fully illustrates).
Siiu'o 18!(1 a vast deal of work Jipon dejfenerations has heeii
done with two methods which are especially well adapted for
yieldiiifi: information, especially in tissues obtained too soon
after the lesion to be of value for study by the method of Wei-
gert.* 'V\w tirst of these methods, that of Marchi, thus far
speakrt strojiirly in Its results for the validity of the neurone
doctritie. 'IMiere is no evidence from its use that a dejjjenera-
tion followinj,' an injury I'xtends beyoml the limits of the lU'U-
rone or neurones whi(di the lesion involves. On the contrary,
the method is mainly of value since it permits the following of
a set of diseased fibres to their termination. Hy its aitl the ex-
act course and distribution of (iowers' tract as far as its ending
in the cerebellar worm havc^ been followe<l. This is only a sin-
gle, although an important, example of its etticacy.
Investigators who have employed the second nu'thod, that
of >»issl,an(l its various moditicalions have been extraordinarily
active. The procedure is an extremely delicate one, and
changes hitherto entirely unsuspected have been detected by it
in various ])athological conditions. Through it, in one respect
at least, the neurone conception has l)een supi)orted, for the
method has demonstrated that, when any portion of an axone
or its terminal raiuitications is diseased, tlu* whole lu'urone to
which that axone l)elongs suffers, the (dianges which oc(nir in
the "stainable substaiure " or " tigroid " of the cell Ixtdy and
dendrites of a neurone after lesion to its axone being now gener-
ally recognized an<l appreciated. As Stirling of Manchesterf
emphasizes, the (dninges whi(di occur after ami)ntati()ns also
point to the individuality of the neurone unit. In another re-
spect, however, the a])])lication of the method of Nissl has
brought into view a ])heiu)menon which at first glance ap])ears
to be opposed to the neurone conce})tion. It has been found
by Marinesco (though, curiously enough, he inter])reted his
observation differently), by Warrington, J and by van (ieluudi-
* Tiu' method of Marelii and that of Xissl. and tiii- results to wliicli tliey
have led, will be referreil to in more deliiil in sui)se(|ii(>iit eli.-iiiters.
f Persoiijii ('omiiiiinication.
X Wiirrinfj^ton, \V. U. (>ii the Slriictiiral AltiTiitions oliserveil in Xervo
Cells. J. Physiol., Ijond. and Caml)r., 18i)8, vol. viii, Nos. I and 3.
%
: I,
;1;M
,<»
m
i«!
IP i
M^
TIIK NKUVors SVSTHM.
r i
i
1'
ten tlmt ill ccrtniii iiistiuiccH the (tutting thr()ii<;li of ii ccrcbriil
Hfiisory lUTVi' between its <;aii;,'li(»u mid the ceiitnil nervoii.s wyH-
ti-rii (or, •:; terms of the neurone conception, sohition of con-
tinuity of tlie iixoiies of sensory neurones of tiie first order)
is followed by chungeH in the nucleus terininalis of the iiervt*
(|uite like those which occur in the cells of the peripheral ^'iin-
<,'lion itself after section of the sensory nerve Detween the f,'an-
fj[lion and the periphery of tlie iiody, or like those which follow
in a ni(»tor nucleus uiion section of the root fibres issuiii^^ from
it. llij^hly interestinj; as the phenomenon is, and as yet insutH-
cieiitly explainecl, it can hardly be said t(t iii any way invalidate
the neurone conception. The fact that an injury to one indi-
vidual in a socit'ty U-ads to tin- detriment of certain otlier indi-
viduals with whom the former individual was most intimately
associated, can not be considered as disproving the idea that
the .society is comiiosed of individuals. And that, in the ease
of the neurones under consideration, the character of the in-
jury in the periiihcral and in the central neurone ditfer is obvi-
ous from the subseciuent history of the two neurones in ani-
mals permitted to live for some time after the injury. In the
one instance typical Wallerian de^'encration with absorption
(piickly takes jilaee, in the other there is at most slow secondary
atrophy.
Histolofiically, there have been since 18!) 1 repeated confir-
mations of the earlier siufjle observations of coarse anastomoses
of dendrites. In niamiiials the findin<j, except in the retina, is
rare, though in lower forms, accordiuff to the recent observa-
tions of Hethe, Xussbaum, Schreiber, and llolnifjren, it appears
to ])e more common. I have myself seen it in the nervous sys-
tem of rabl)its, and have observed, what others have seen also —
namely, the partial fusion of the cell bodies of two neurones.
Hut these unusual conditions, even were they common, are
surely of but little consec|uence when brought forward as argu-
ments against the individuality and relative independence of
the nerve units. If one thinks for a moment, the unreason-
ableness of the objection becomes obvious, for who would con-
sider seriously the argument of an anthropologist who contended
that the human race did not consist of separate units and indi-
viduals on the ground that cases of double malformations like
the Siamese twins, the Janus-headed monsters, and the various
instances of epiguuthi, thoracopagi, undfcefim in fiela are known
•I (
DKVKhOi'MKNT OF TIIK NKUllONE CUNCKIT.
47
m\
to oorur;"' Kvcii if iji tlu* hciirt of Africa soincwiioro wt* hIioiiM
conic to fiiKJ tlmt tlicrc cxistcil h tcrrililc iiiitl swift race such as
J'lato makes Aristopliaiics dcscrilu' in tiic Syiiiposiuin, \vc (loiibt
very mucli if we slntuld he williti},' to jjivc up the jrcucral view
tliat humanity is u mass of multiph* units, though douhtless we
Hhouhl have to modify our couci'ptioii aH to the p<tssil)ility of
variety in the units, or admit a ttond of iniion hetween tlicni
more intimate than tliat to wiiicii we are accustomed.
On the whole, however, it may be said with fairness that the
control instituted i»y hundreds of histoh)gists in various parts
of the world has, ])ractic;dly, in every instancj' in which the
method of (iolgi or the metiiod of Khrlich has been employed,
gone to eontlrm the conception that the neurone is a unit in the
sense of Waldeyer.
Passing now to the last iiupiiry, let us examine the original
contributions dating since |S!»1, and see if in them we can find
any facts wliich necessarily nullify the validity of the neurone
conception, in this connection only two researches present
themselves which are likely to be brought forward by its an-
tagonists. One of these is the investigation of Held concerning
tlie kind of relation which exists between the terminal branches
of an axone of one neurone and the cell bodies and dendrites
of other neurones with which they are connected ; the other is
the much-talked-of research of Apathy, emanating from the
Zoological Station at Naples.
Ileld's* communication is one of very great importance, rep-
resenting, as it does, the most careful application of modern
cytological techni(|ue to the study of the nerve cell and its pro-
cesses. His findings concerning the tigroid and the ground
substance of the protoplasm, brilliant as they are, do not con-
cern us here. The observations of Held, however, which must
here be taken into account are those Iji which he describes
fusion of the terminals of the a.xone (including the end rami-
fications of the collaterals) of one neurone with the protoplasm
of the dendrites and cell bodies of neurones of a higher order.
Held agrees with other investigators that in embryonic tissues
and in early youth the neurones are entirely independent of
Ml
w
i1il
* Held. II., Bcitriigi- ziir Structur der Nervenzolli'ii unci ihror Foitsiitze
(zweite AVjIiaiullung) Arch. f. Anat. u. I'hysiol., Aimt. Al)th., Leipz., 18t)7.
S. 204-294,
Hi
:'^'
it
Mr
n\
48
TIIK NKl{ vol's SYSTEM.
Ii/i(l II K I'll i.
Termiiiiil ii.i'inii
^1
,l.ri)/i(' of rill
I'l
ono aiiotluM' (oxci'pt fur iiii occasional (U'lulritic or otlicr anasto-
mosis), in tlioso stages, which, l)y tlio way, correspond to those
of the majority of (iolf^'i i)rep-
arations, he finds, in areas es]>e-
cially well siiiti'd for the study
(e. ij., tlie nucleus of the trape-
zoid hody), that when the ter-
minal of an axone comes into
contact relation with the cell
hody of another neurone one
can always make out where the
l)rotoi)lasm of the one neurone
ends and where that of tlie secv
ond he<jjins, inasmuch as the
line of demarcation is more re-
fi active than the adjacent })ro-
toplasm ( Fiij-. IS). Held finds,
however, that tiiis refractive
limitinix line is not demonstra-
hle in the adult, and conies to the conclusion that durin<; the
})roccss m growth the protoplasm of related neurones fuses.
Iiulced, ill some instances there is I'videuee that the termi-
a. Is. — Cell riiiiii Miulciis ('(prpdiis
Iriipc/didci of ncwiioni cat (Al'tcr
II. Held, .Vnli. r. .Viiiil. II. I'livsicil.,
.\iiiil. .Mitli. ( ls<l7),'riir. xii, I'"i-. )>.)
FixMtidii with van (icliiielilcii'.s
iiii\liiic ; slaiiiiiif; willi inm-ha'iiia-
tiiN.vliii. 'I'lic laijjf a.Miiif is seen
Icriiiiiiatiii;; ii|i(in tlic cell and <'\-
liiliiliuK what Meld calls ccincics-
cciicc relation. The small aMiiie
with itsaxinie hillnct; isarisint; iVoin
the cell hody shown in the liKlire.
A
■I
-i.f.
Fl(i. lil.— Cells IVoin the I'lc. us coi-|ioiis tiai)ezoidei of thi- iidult lahhil. ( Alter
II. Held, .\ich. f. Anat. n. rii.vsiol.. .\nat. Ahth., Leipz.. |S!(7, II. :{ n. I. 'I'al'.
xii, V'\%. t. ) .\lcohol (ixation : slaininLj with iidn-ha'niatox.^lin ; ditleiciit
t'oiiiisol' intracellular lilires y'l.f.) are shown. The lilire I'liteiiu^; th. cell in
the lower rinht-hand corner of the linnre is, accord : to llild, ccrtainl.v an
axis cylinder. .V, nucleus.
I •
m
DEVKIiOPMKNT OF TUK NKniONK TONOKPT.
49
!
;
nil
50
THE NKHVOCrS SYSTEM.
nals of one lu'iironc pluiijje deep into tlic coll body of another
neurone and even come into close proximity to tlie nucleus of
the hitter (Fi:;. 1!)). He describes the relation as one of
"concrescence." lleld's pictures are very convincin<r, and one
must certainly admit that his work proves the existence of
much more intimate relations amonjif tlie neurones than the
studies made witli (iolgi's metliod had led us to suspect (Fig,
*^0). And yet, in f()llo\vin<!f Ilehl's various articles closely, one
tinds that this histologist, notwithstanding the disappearance
of the refractive line of demarcation, is able, cvcu in ndnU
sf(f(/('s,to distinguish the protoplasm which belongs to tiie termi-
nal axone or collateral of the one neurone from the protoplasm
of the cell body or deiulrite of the other, liy a lucky hit Held
Capillaries contuining red blood corpiigclen.
■/p^^^.^
:/<>.^;^^'-^
Ih iiiliites of mitral cells.
Fl(i. 21. —(iliiiiicnilusoiriictiprins from adult nililiif. ( After II. IIcM. .\w\\. f. .\iiiit.
11. I'liysiip].. .\n;il. .\litli.. Lcip/... IsilT. 'I'lif. ix. Fi^'. l:?. ) ( 'lirciiiic-ipsniic ti.xa-
tiiiii iiiiil staiiiiiif; liy .Mtmanii": inctlinil willi acid fiudisiii : sli^lit ditl'iriiitia-
tioii. .\ disliiicl ditrfrciicc can 1)1 made out hctwccii the uuiulicr of uciiro-
soiiifs ill the hcKiiiiiiiifisof llic dendrites of I lie luilral cells and llie term i nals
of the iiervi olfactorii. The niiildle part of the >;lonierulus lias not been
drawn.
seems to Inive discovered a method of staining certain minute
jtarticles (his neurosomes) in the ground substance of the pro-
toplasm of the neurones — a method whicli stains thcni intensely
DEVKIiOPMENT OF TIIK NKL'RON'K CONCKI'T.
51
;iii(l k-avt's the other structures but dimly i»r not iit all tinged.
It would seem that, according to his report, the neurosomes are
('(i/iiiiiii/
■•• .. • • :^"4 ■'.'•■ X 'k- ■■ ■ ■■*■■
■• .••*■ ♦■•.; t'.^ .'o^ > ';\\\,^P
.Yc/Tc ((7/ ii/ tliv iiuiliiiiliir siiiif
rniir.ifi ilfiiilriten nf Purkinji' I'lllf
Fkj. 'Z'l. — A iMii'liiiii ipf tlic iiKilcciiliir /.(Pile (if llic <'<'n'l)cllimi nf an luliill nililiit.
(After II. Ilclil. Arch. f. Anal. ii. Pliysinl., \\\;\\. Al)tli.. I.ciiiz.. Isil7. Siipjil.
15(1.. Taf. .\iii. Fij;. 1.) I'ai'allin section 1..") inicrcms tliick. I'.rytlinisin-
nictliyifnc-liliic. Tlic |pcriil('i..lritic lirancliis of lianion y Cajal's cliniliinj;
tilu'cs liKik like •;rannlar l)iinils ipwin^ tii tlif procncf in tlum ;)!' laifjc nimi-
licrs (if nciinpsdnus.
I , .'1
■ i.i
4i ' ■; <
x-y
far more closely aggregated in tlie tixis cylinder, and especially
in it.-! terminal l)ranches, than they are in the ])roto])l;ism of the
cell bctdy or of the dendrites of ti neurone. Thus, in the olfiuv
tory glomeruli (Fig. 'l\) it is very easy to distinguish the axoues
of the ncrvi olfactorii from the dendrites of the mitral cells and
of the brush cells, both of whicli, as is well known, entt'r into
the forniiilion of these curious bodies. Agitin, in the molecular
liiyer of the cerebelliir corte.x, lleld's netu'osoine nu'thod out-
lines accurately the ])osition ami relations of the terminals of
the ;ix(»nes which climb trellislike along the trunks of the huge
limbs of the cerebelliir forest whi(d» is made up of the dendrites
of the I'urkinje cells (Fig. "i'l). Ileld's contributions, there-
fore, tar from disproving it, are contirnuitory of the neuroma
doctriiu'; ami, its a mtitter of fact. Held represents one of the
ablest of the (ierniitn iidherents of the doctrine.
iilHi*
52
THE NERVOUS SYSTEM.
H i
Advortiiijj; HiiiiUy to tlio inv(>sti<fati()Jis of Apathy,* one finds
ill tliciii the <j;reate.st stiunl)liii,i;-l)h)('k to those who, |)erha])s on
aeeoiiiit of hick of familiarity with the exaet priii('i])les of the
neurone doetrine and the history of its foundation, are inelined
to think that it is jeopardized. A skilled teehnieian, well
known to the ])i<)lo<,n('al world as the author of a treatise on
the teehni(|ue of aniinul ;iior])holo<fy, and generally reeof:fnized
as a most careful and painstaking worker at the Naples Marine
Lal)oratory, after several years of specially directed study, dur-
ing whi(!h he has elaborated an entirely new mode of bringing
certain finer structures within the nerve cells into view, has
tinaily, in a long article of more than two hundred pages, ])re-
sented the nuiin results of his invcistigations upon the nervous
tissues to the scientific world. While Apathy has studied verte-
brate tissues to a limited extent, the majority of his o])servati()ns
have been made u])on invertebrates, especially upon the leech
and the earthworm. His technical methods need not be en-
tered into here. Suffi(!e it to say that for the most part his
technique is original with himself, consisting, in addition to a
method of staining with methylene blue, of a ha'juatin method,
and an es])ccially modified gold-chloride method which can be
api)lie(l not only to ^'resh tissues but to fixed tissues as well.
To sum up his views in a nutshell, Apathy has been convinced for
some twelve years that the nervous system is (Composed of two
varieties of cellular elements entirely different from each other
— " lu'rve cells" and "ganglion cells." 'i'lie "nerve cells," the
architecture of which is quite in accord with that of muscle cells,
give rise, he thinks, to mniro-fibrils (Fig. :;j;j). A neuro-tihril
in turn passes out of a jjrocess of a "nerve cell " and then goes
through a number of "ganglion cells," and ultimately, after
leaving the last " ganglion cell," with which it is connected,
passes more or less directly to a muscular fibre or to a sen-
sory cell. The neuro-fibrils are (as conducting substance) for
the " nerve cell " what the muscle fibrilhe are (as contractile
substance) for the mus<!le cells. The pathways to be followed
by the neuro-tibrils are predestined from the earliest embryonic!
stages, for they correspond, according to Apathy, to the inter-
cellular ])rot()])lasmic bridges.
!»i|
* Apathy, S. Das lisiteiidn Eloiiient des Nerveiisystorns iintl seine topn-
gnipliisdicii nozicliwn^ifen zii deii /icllon. .Mitth('il. jiiis dcr zool. StiiMon zii
Nftipel. lid. xii {l«!)7), II. t, S. 4!»5-748.
•-^^^--n.
DEVELOPMENT OF TIIK NEUHONK CONCEI'T, 53
t 'i •
54
THK NP:RVOrS SYSTEM,
: I
curly as 1 885
fibrils. Sonio of
"ffiuiglion cells "
into the sense
(Fig. 27) cells or
The " ganglion
pass, and which, if
Each neurofibril is, Apathy states, made up of a large num-
ber — near its origin, at any rate — of " elementary fibrils," and
in the course which it follows elementary fibrilhe arc being
given otf at short intervals, until finally the neuro-fibril itself
mav be reduced to a single elementary fibril. Apathy as
was able to follow the paths of single neuro-
them grow toward the centre into the
(Fig. •■i4), others toward the periphery
cells (Fig. '2i) and Fig. ::i(i),or into muscle
)lood capillaries.
cells " through which tlie neuro-fibrils
Aj)j'ithy is correct, sujjjily the force
whi.'h is to be coiulucted along them,
appear to be complicated in structure.
Thus in the leech the body of the cell can be divided
into a series of more or less concentric zones. At the
periphery are two zones, an outer and an inner, consist-
ing of neuroglia, which are more or less separated from the
Fi(i. 'M. — Liu'Kc iiliiripiilar Kiiiijilidii cell (if llic ventral paraiiicdiaii (icld id' tlio
alxlipiiiiiial (111(1 oriiiiiiliiicus. (Al'tcrS. A|>:illi.v. Mittli. aiisdcrzonl. St. zii Nca-
pcl. I'ld. xii. IsilT. II. t. Tal'. .\.\vii. Fij;. 7. i .\ primitive liliril, s/ifi';]. i:s .seen
(111 its way III a yanj;liiin eell heimnin;; tliiiiiu r. (iwinj; to tlie einissinn of the
side tihrils. A very cuniplicaleil iiitraeellidar relieiiiiini nl' neiiru-lilirils is to
lie made out in tile format ion III' wliicli the piiniitive lilirils of all tlie pmeesses
lake part. /.■/.■. nuclenliis : /,■. nucleus, a and ^ are processes conlainin;j one
primilive liliril in each, whicli arriving in Ihe cell hody split np into seveial
liifiirialin;; nenro-liluils. The |iriniilive Jihril in a can he followed for a ver.y
hint; distance, heinii thicker at a distance fiom the cell. The coarse lon-jitu-
dinal piiieesses y and iS contain a larj;e nnndier of primitive lilirils whi( li, as
far as they can he I'ollowed, do not unite to one liliril.
DEVELOPxMENT OF THE NEUKONE CONCEPT. 55
' '^ pin
Fio. 25. — Tlic ])lcxus (tf nc'iiro-tibrils in sonic retinal colls,
II, h. <: it. (if the lliinl n^lit cyi' ol'tlic Iccfli, ( After S.
Apiitliy. Mittli. iiiis (ler zudi. St. zii Neaixl. Hd. xii. isit",
II. t. 'i'al'. xxviii, Kif;. V2. ) Tlie relation ol ilie inieleus,
A', to the i)lexiis of neuro-filirils is well shown. "Con- ''
ducting " anastomoses visilile helween the eell c and (/. ;»/, " eondnctinK "
jirimitive lihril ; (oi, "eondnetinK " anastomoses: r/;«. radially striiK'd zon((
of the vitreons of the retinal et Us ; Irjn. (dear zone of the vitreons of the ret-
inal cidls; iilij. pigment; rli, projeetinn hillock of somatoidasm.
;//,/) <7i/.7i" ^.
rz
kzo . ^— ___^ .
/|2() IIZO '■ .
ar ic
FUJ. 20.— A snhepidennal sense cell, retiu.il et II from pseudo-hnuK hellion. (After
S. Apiithv. Milth.ansderzocd.St. zn Neapel. Hd. xii. 1S!I7. M I, Taf. xxxi. Fij;.
!>. ) II. vitreons ; h. ctdl nnidens : c. cell hody ; ir. the limiting line of the diame-
ter of the vitreons; m: the outer contour line of the periidiery id' the somato-
plasni immediately adjacent to the vitreons: ijni. prohalily thin ^.'lia memhrane
whi(di accompanies tin' "conductinK " luimilive tiliril. Ipf. oiit>ide the in riti-
hrillar mantle as far as the cell. The peri lilnillar mantle is lost at the cell sur-
face : c/i/,/,-. (diromatic nm leolus ; ;//.•;>. vitreon> of the retinal cell : (/:«. radially
striped zoneof tln' vitreons: h.u. idearzone of the vitreons : /7,;), internal hody
\ hiiiciikorr)er) of the vitreous: A-.'/. j;rannlar zone of the vitreous.
I »1
H
56
TIIK NKH vol's SVSTKM.
cell l)(i(ly projM'r by tlic so-cjiUcd outer alvcoliir zone. Tlio
periphery of tli(^ cell jn'ttpcr consists of iiii outer cliroJUiitie
zone, iiisido wliicli is an "■ inner Jilveolar zone." Inside this
Fui. 27. — The (listrilmtidii of (lie iiciir«i-lil)rils in (lie ciriiiliir iiiiisclc lihrc of tlic
iiili'stiii;il wall of i)ciiitiili(lclla. ( AI'Iit S. Apiilliy, Mitlli. mis der zool. SI. y.n
Ncapcl. iiil. xii, IsitT. II. t, 'I'aC. \.\xii, Fiy, ;i, ) Only a iclalivcly .slioil piece of
llie lent;. Iiand-sliapeil llalleiieil-onl niuscle Mine is repi'es<'nle(l. The Inaneli-
iuH 111' the enleiin^' IK iiici-fihiil can !»■ t'lilloweil lliniiit;li the whole Ihiekness
oC the (ilire. /(/', " conclliclin^ " primitive lihril ; hi, ninscle lihre ; », place
where "conilnctiiiK " piiniilivc lihril tnrns an<l appears to end.
a^aiii is an inner eliroinatic zone, whieh in turn is separated
from the nucleus by the so-called perinuclear zone. in the
latter is situated a small centro.soTnelike body. Inside the
<faii<flion cells a reticulum of line librils derived from the neuro-
fibrils in transit can be stained a betiutiful deep violet color by
Apathy's chloride-of-<(old method.
Accord iniJt ^*^ t'^^ ^^'^-^^ <>f the cells and to the arranj^ement
of the neund reticulum inside, Apathy distin<fiiishes in the
leetdi two nniin types: (1) the hir^e ^•anirlion ct^ll, and {'i) the
small f?an<flion cell. It is to be borne in mind that the fjjiin-
glion cells in this anijual are unipolar, the so-called "stem pro-
cesses " j,n"vin,ijc olf near the cell body a number of ])ro(!esses
which ai)pear to be comparable to the dendrites of higher
forms, the main (nnitinuation of the process representing prob-
ably the axone.
In the large type of gangliim cell (his Type (i) the relations
are described by Apathy somewhat as follows : '^Fhe neuro-
fibrils arriving by way of the i)yrif<)rm process of the (fells enter
the proto[)lasm, breaking up into elementary fibrils which
diverge nieridionally to ramify in the external chromatic zone.
(The cel!s of this type possess no distinct internal chromatic
zone.) Free anastomosis amoTig the elementiiry fibrils inside
the ganglion cell appears to be the rule. Having arrived at the
1 1
DEVKLOI'MKNT (>F TIIK XKIKONK CONCKl'T.
1
iM
iH" I'f
Vui. 'J8. — (^^olossiil ^iiiiKlioii c(ll (TyiH! ;;) IVmii tlic Icccli. (AI'Ut S. Apatliy,
MiUli. aiis (Icr /.(Hil. St. zu Nfiipc'l, Hi'l. xii. \m~, II. I, Tal'. x.wiii, FIks. 4, 5,
iliid <i. )
(1) rostiTiiir mcdiini Hcctiiiii. hql\ (•(iimcctivc-li.ssiK^ niiclciis; ijlh. aVvA
slu'iidi ; Aip, iiiii'l('iisi>rtlic KiiiiKlioii ceil ; Ijif, " I'oiidiiclinjj " priiiiitlvf filiril.
(!J) Cross scctiun. k. miclciis. (;{) 'I'lic iiicridiaiiliki^ dcciissiition (if the iii'urd-
librils at tlio poli; of the cell is illustiiit^ul.
68.
TIIK NKUVOl'S SYSTKM.
ill'
■1 V!
side of tlio cell most distiiiit from the stem profcsa tlio nciiro-
lil)rils turn ahout iiiid iij,'iiiii j)luii<,'t' tliroii;,'!) tlic (u'll, coiivit^mii;,'
to puss out of it l)y wiiy of tho pyriform process, whicdi is thus
seen to curry two sots of m'uro-tll)rilla', which Apathy hcliows
serve ill the one cusc for cellulipetul und in the other for cel-
lidifu;,^! conduction (Vijr. "-iS).
In the small type of <i;an<,dion cell (his Typo K) th(! rela-
tions, it wouhl u]»i)eur, are somewhat diifereiit. I lore the pyri-
forni stem process contaijis u sin^^lo thick neiiro-lihril in its cen-
tre, which Apathy assumes to l)e celluliru^''al and motor, and a
numher of liner neuro-lihrils peripherally placu'd, which he he-
liovos to bo cellulipetal and sensory. Ho describes the finer
l)eriplioral nouro-tibrils as follows : They uro s(^on to enter the
cell body and, passinj; out to the peripheral ])art of its proto-
])lasjii, there to break uj) into a complicated plexus composed
of anastomosing elementary fibrils in the outer chromatic zone.
From this jieriphonil plexus there pass throu<,di the "inner
alveolar" zone radial branches to the internal chromatic zone,
in which is to be se(Ui another fine plexus of elementary librils
which, anastom()sin<? and converj^injj;, finally form the sin<fle
strong motor neuro-libril, which passes out of the (fell through
the very centre of its pyriform })rocess (Fig. 2'.)).
In other animals studied by Apathy there are (rolls with
definite dendrites entirely se])arato from the axone and, in these
the celluli})etal neuro-librils enter by way of the dendrites,
ramify and anastomose freely inside the cell body, und then,
reuniting, take their exit from the cell by wuy of the uxone.
Similar relations exist in the ganglion cells of the vertebrates
which he has studied thus far. His descriptions of the iien-
roglia and the relations of the glia (ells to the nerve cells,
interesting as they are, need not now detain us, since they
have but little bearing, if any, upon the to2)ie under discus-
sion.
As to the relations of the Tieuro-fibrils to sensory surfaces
on the one band and muscular tissue on the other. Apathy
makes very definite statements, especially in the last chapter of
liis article. A neuro-fibril entering the cytojilasm of an epithelial
cell of a sensory surface in the leech breaks up (very much
as in a ganglion cell) into a fine reticulum (!om])osed of the
elementary fibrils. A large luunber of the constituent fibrils,
hoAvever, perhaps the majority, leave the cell in order to take
■-'p r
m
DKVKLOI'.MKNT oF TIIK NKUItONK CONCKPT.
r.9
\mr\ ill the fonnution of a cnnipliciitod intorcpitlicliiil liltril
plexus. For tlic iiiU'rcrttiii}^ details eoiiceniinj^ the iiiiiervatioii
of tiu' siiperfieial epitiioliul cvWn and tlio sul)epiderinal scjise
cells the orifjinal article should be consulted. In the muscular
tissui', however, a very dilTen'ut distribution of the lu'uro-
fibrils is encountered. .V neuro-fil)ril here also breaks up into
cleuu'ntary fil>rils which ramify inside the muscle cell. Hut
altiiou<jh numy of the fibrils emerge from it, insti'ad of formin<?
a complicated reticulum among the mus(;lo cella they pass on
A;
I
•'•/
//
l''l(i. ~'!t. — 'riirt'c pciir-sliapfd KJHiJ-'li'"! rcUs (if 'r,V|if A', iii l<in<;itil(liiuil section
I'nnii tlic Icccli. ( After S. Aicilliy, Midli. ;iiis der /(ml. Si. /.ii Neapel, lid. .\ii,
ls<i7, II. I, Till', xxviii, Vift. 7. ) 'Die inteiiial ur pc riniicleiir plexus id' ncuio-
lilirils is well sliowii. as are iilsii the radial lilires. The periidienil plexus is
indiiated. af. axis tihrils whicdi .\path.v takes to lie iimldr: iiii. external in-
traeellular plexus III' neiini-lilirils : /)/';/. internal perininlear plexus of neuni-
lihrils ; rJiif. eellulil'n«all.v " eoniluetin;; " iiriniilive liliril ; i/i/'V', eillulipetall.v
" eduduetin^ " primitive liliril; /,•. uinleus (if the ^'an;;li(in cell; /;/'. radial
lilirils ennnerliui; the external ph'xus with the internal plexus iil' neurn-
lilirils; .il. stem pn)ee.s.ses ol' pear-shaped ^jauKliou iidls.
to enter and innervate other muscle cells. The neuro-fibril of
a single a.xono would, therefore, througii its <;lenu'ntury filirils
innervate perhaps ii considerable nund)er of muscle cells, (tne
nerve cell may, Apathy sttites, be put into c(mtinuous relation,
l)y nu'iins of one or more primitive tibrils, with sevenil ganglion
cells, iind one ilbril can be connected with ji numl)cr of scusi'
i'ells. liut while one "■ ganglion cell" may be connected with
IMAGE EVALUATION
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TIIK NKHVOUS SYSTEM.
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i I
sovenil " nerve cells," n given sense cell is never connected with
more tluiii one nerve cell.
From wliiit has heen said, aTid from a study of the accom-
panying illustrations, especially of Fig. ;U), the main tenets of
Apathy may be gathered. And wc must now ask whether,
granting all his findings, and even his tiieorics, to bi^ in accord
with the facts, the ncuroiu' doctrine would be nullihed by
them. Although the opinion has been expressed that it would
have to be entirely given uj), or very seriously modified, I must
confess that such a view of the matter would seem to be, to
say the least, premature. That the neurone conception, as it
has been lield by many, would have to be materially altered,
there can be but little doubt, but many views of the neurone
conception sind what Waldeyer actually defined it to be are by
no means identical. Nor (^aii it be admitted, as a nundier of
autiiorities, including ap})arently Apathy himself, api)ear to as-
sume, that in the research emanating from the Naples labora-
tory we have a confirmation of the doctrines of (Jerlach, in-
asmuch as (Jerlach's diffuse nerve network and its relation
to axis-cylinder processes and dendrites involved conceptions
somewhat different from those which Apatliy takes tiie respon-
sibility of fathering. A}i;ithy's Klenientargitter, however, stands
very close to the conception of Gerlach.
It would seem, then, that were Apiithy's observations and
theories in accord with the facts, the Jieurone doctriiu^ as con-
ceived by Waldeyer, would not have to be seriously modified,
much less abandoned. Some of the a])parent novelty of his re-
sults deperuls upon the fact that, in the first place, he is dealing
in the main with tissues which are not very familiar to many
Fl(i. :?0. — Schcniiitic rcprcsciitiition of tli(^ coiirso aiul (Milliccti'ms ol'llic cniidMct'
iiiK piitlis ill :i Iniiisvcrst' scctidii iil'tfic soiiiifc nl' tln' Ici^cli. (Al'lcrS. Ap/itliy.
Millh. iMisilcr /.(M)l. St. /ii Nc;ip"l. lid. \ii. II. t. lS!t7, Tat', xxxii. Kiu. (i. ) Tlii'
Iwi) halves of the s;an;,'linii arc shown with tlic motor fiatiKlioii cells, iiiii, ami
the sciison- or simple coiincctili}; ^'aiiKlioii cells, i/.v/. Three kimis of nerve
.spimlles or nerve lihres are shown. The hehavior of t hese inside the cent re,
fin'ir dislrihulion in the central lihre mass, aTi(' their connections with the
U;uiKlion cells, are ilhistrated. further, the hehavim- of tliese at the
peripher.v is pictured : muscle (ihres and epidermal and subepidermal sense
cells, fre<' end hran(diin<{s in the epidermis, /Vc. ,\t the point marked ii .s
Kclil is indicated a plai-e where a sensm-.v tube benils around in a loniri-
tuilinal dinction into the central lihre mass. The place .v/n/ indicates where
a senscu'.v bundle turns in a hin^iludinal direction in the cent r.il lihre mass.
" ' '(inductinK " hridj^i'S between the uniscle lihres are shown at iihr. iin,
"condnctin.i;" anastomoses : rii. cuticula ; c/), epithelium ; ;/:. ^Mnf;lion cell ;
nif, mnscde librils; iiiii.s, nioliu'-nerve spindle; /»/)/, motor primitive (ibrils;
.s/v, ' ;)ithelial .sense cell; .vc, snluailicular la.ver of epidernus ; sh, sensor.v
Iiundle (one kind of sen.sor.v- nerve (ibre ) ; .v.v .si'lil. sensory tube (the other sort
of iiervi! (ilire) ; zkii, nucli us id' a " nerve cell " (not of a "f,'ant;lion cell " ).
DEVELOPMENT OF THE NEUllONE CONCEPT. {)\
I
Fig. W).
62
TIIK N Hit vol's S VST KM.
I
f !
neiu'olofjists, namely, tlic nerve cells and fil)res of iiivertelirate
aniinuls, and in the .seeond plaee iiis inddieation.s thus far con-
sist ])rinci])ally of an objective description of his own findinjjs
witli iK'rticular methods devised l)y himself, and pay bnt little
attention to the work of other investigators, so that the casual
reader may, frotn lack of a(lo()uate comparative data, fail to
distin,<j;uish betueen actually new dist^overies and descriptions
which may withont unfairness be found to (ioincide in many
respects with those of other stuch-nts working with ditferent
nietliods. I feel convinced that when Apathy ful'ills his
l)romise of supplying us with a still more len<^thy commu-
nication 'in whi(di the results of other investififators are to be
compared with his own and properly valued, those who have
been inclined to look upon all his observations as entirely
uni(|ue will be disabused of their error. Tiiat many of his
observations are entirely new must be frankly and thankfully
admitted ; that the technique he has introduced is altogether
oriji;inal, and evidently higlily valuable and well worthy of ex-
tensive api)lication and widespread control, must be freely
granted.* .Vll that 1 wish to say, and that without any desire
to detract from the merit of his laborious researches, is that an
attentive analysis of the actual findings of Apathy shows that
there is far less absolutely novel and revolutionary in them than
many seem to imagine. For, when one thinks of it, the form of
the i-ells in invertebrates has long been known, the nnipolarity of
the elements has been generally figured and described, the fact
that the pyriform i)rocess corr'^sponds to both axis-cylinder
process and dendrites is stated in the text-books, the irregu-
larity in the distribution of the "chromatic substance " in the
cells is easy to make out in Nissl preparations; the existence of
the so-called intercellular bridges, if not for the cells in the
* Tlic rciimrks licrc made are not inteiulod to be a criticism of the v(M-y
imjKirlaiil cdiitribiition of Apiitliy. hut ratlicr to oountcract an impri'ssioii
wiiicli seems It) lie gaining ground thai the whoh' or at least a large ]iarl of
our previous ideas eoncerniiig the architecture of the nervous system have
been subverted l)y the results of his studies. Are we not more just and at
the same time kinder to Apilthy if we simply accept gratefully and for what
they are worth the wealth of new facts with which he has provided us. than
we should lie were we to give currency to the impression that they ai'e en-
tirely r(>volutionary and out of accord witl. the great principles wiiich com-
petent neurologists believe to be incontroverlibly estaldishedf
I ^
i'
^■
1)KVKL()I»MENT OF TIIK XKrRONK CONCKPT.
03
ncrvoU'! system, at least for many of the cells of the hotly, is
taufflit and demonstrated in every histolotjical lahoratory, and
the lihrils in the pnxH'sses and the reticula in the eell hody
have l)een the o])jeet of study and the topic of discnssion, too
often of hitter polemic, for at k'ast two generations. 'I'he very
nenro-fihrils upon which \patliy hases his doctrine were lirst
well seen, as tlic author himseli" states, l»y Knptl'er in the
tissues of vertehrates.
The essential novelties in A]t;Uhy"s coiitrihutittns, in addi-
tion to his nH)dilications of techni(jue and his woiuh-rlul de-
serii)ti()ns of the details of the fihriUary appearances inside the
protoplasm of cells stained hy his methods, whicli arc undoubt-
edly of great value, are his deductions and hypotheses, of which
all, in my opinion, maybe pci'niitted, at least for the present, to
be judiciously skepticud. How does he know, for example, that
the structures which stain violet by his gold method actually
rc[)resent the conducting element in the nervous system ? It
may be true, hut the Scotch verdict " Not ])roven " is here
most api)licablc. Again, on what grounds does he sc[)arate the
"nerve cell" so sharply as a ditfi'rent entity from the"gan-
'dion cell" and hov; does he know that the "nerve cells" ])uild
the coiulncting element, and that the "ganglion cells " supply
the force to he conducted y These mm/ be the functions of
these two sets of element:^, but we must not neglect to point
out that the evidence is not yet convincing.
As yet 't is altogether too early to pass judgment upon
Apathy's views; much work must be done by his methods by
other observers before the exact value of his tindings can be
properly estimated ; but were all his statements true, is there
any reason to doubt that neurones will continue to degenerate
as units, as heretofore ; that the i.'rvous systems of our cjiildren
will continue to he built up during (Un'elopment of rcjteatedly
dividing neuroblasis in the way with which we are familiar, or
that (iolgi's method in the thirtieth century will have lost its
power of demonstrating here and there a parti(;ular nerve unit
or neurone in its entirety? Again, would the confirmation of
the existence of continuous fibrils or fibril systems passing
through a whole series of nerve elements necessarily militate
against a unitary conce])tion ? I must say that I can see no rea-
son why it should. Waldcycr, in his article in 18!)1, after dis-
cussing the probable modes of conduction by means of the neu-
I
^ii
5)1 !i I
64
TIIK NHIiVOUS SYSTEM.
roiics, jiildcd, it woiiM sccin almost with pniplu'tic; iiisij^lit, the
followiiif,' .stiitciiiciit : " If we ansunu! with CuAgi and H. llallor
the existeiioo of nerve networks, the eoiieeption is somewhat
modified, bnt we can still retain the nerve nnits. 'IMie limits be-
tween two nerve units would then always lie iji a lu'rve network
and not, anatomically at least, he exactly delinable with our pres-
ent methods." We do not re<rard the connective tissues as any
the less cellular because they build white fibres, yellow elastic
fibres and membranes, and retiindum ; we do not look upon the
studies of Weigert and .Mallory, whicdi deal with neurojjflia
fibrils and their relation to the neurojjflia cells, as subversive of
the doetrine that neuro^'lia cells exist ; nor do we, because
Kromayer and others have demonstrated, by particular methods,
fibres runnini^ through the bodies of a number of epithelial
cells, cry out that the cell doctriiu* must be given up. One
might just as well assert that theie are -lo organs in the body
because there is a general vascular system. There may be units
smaller than cells, and in all probability there are ; there may
be, and probably are, in the nervous system units other than
those generally described, and it is important that we should
find out all that there is to learn about them ; but that the
human body is made up largely of a mass of cells, and that the
human nervous syste.i is made up largely of great numbers of
cell units, the so-called neurones, would seem to be facts too
firmly established ever to bo utterly overthrown.
iiiiiy,
A III
LTI-Cp
allot I
iiiiil.\
ill Sll
iiiori
iiilior
tics 1
(Iocs
of til
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Allir.
ill
I
if ill
i m
* n
NoTi:. — In spciikintjf of the nerve cells (or neurones) as individuals, it is
not to be I'orfjfottcn that in the animal aiul vegetable kiiif^doms we have to
deal with individuals of difl'crent orders. Whereas some individuals con-
sist of siuf^lc cells and live as independent orf;aiiisms, other individuals are
united with one another to form a more comjilex creature, an individiud of n
higher order, as, for e.xample, iv multioclliilar animal or i)laut. Kvery indi-
vidual possesses certain iiiorpliologieal and physiological charactcrislicis and
forms an elementary unit endowed with fundamental properties of life, pos-
.sessing the power of assimilating food, of excreting waste substances, of
increasing in si/e. of reproducing its kind, and of reacting in some wav or
another to stimuli which alTect it from without.
An amo'ba. on the one hand, represents a unicellular organism, an inde-
pendent vital unit, but an individuality of a very low graih'. A multicellu-
lar animal is, on the other hand, a unit of a mu<;h higher grade, consisting
as it does of a nuiss of anuebalike units, eaeh of the latter possessing the
fundamental projiertics of life, but each being somewhat less independent
than a unicellular organism. The cells in such a complex cell state are
none tfie less units bet'aiise they are to a degree subordinated. Su(!h units
I)KV|.:i,()|>MK\T OK TIIK XKl'llONH CONCKI'T.
♦ ;')
may, liowevcr, Ijihhxhc in('a|ml)l(> of cxistoiKH! iiiiio|i(MuU'iit of lln>ir fellows.
A iiiullJiHtllular iiulividiiai (person) liki^ u hiiinaii Ix'iii;; eonsisls of an a<;-
t;refjate of l)illions of cells so intimately (■onne(;le(l witli ami I'elated to one
another that tiic eonihined aelivities of the imlividual cells jjive the idea of
unity, liut each cell nevertheless continues to have a life history of its own.
In such a democracy, as it were, it is not surprisiuf; that there should \w
iiiori)holoj,M<al dilTercntialion correspondinf^ to the physiological division of
lahor necessary for the welfare of the whole. The s|)ecializalion of iictivi-
ties renders I'ach cell less independent than a cell of a sinj;le orf^anism, lint
does not rob it cut irely of its ('haracter as an individual. I''or a discussion
of the ipiestion of "individualities" in Nature the reader is referred to tli«
writinj^sof Huxley, N'iiijeli, iijieckel, S|)encer, and espe(?ially toO. Ilertwifj'H
Allgeineine Anatomie und l*iiysiol();;ie der (lewehe, ,lena, 1H!W.
: - V'i :u,#^
I
i
I ,111
\
1 1- ■ '
i 111
m
W\) \
■tj.'j '
■•1 !
SK(TI()N II.
THE KXTKKNAL M()RI'lI()L()(i V OF NEURONES.
CII.MTKU VII.
Tin: KXTKRXAL FOKM OI" TIIK CKLh liODY AND ()!■ TIIK
DKNDKITKS.
Neurones lis cells — ?l\teriial inorpiiolnfry of iieiirones — The shujie anil size
of the cell IxuJios — 'i'lic pnitophisiiiic processes or dendrites — \'nricosities
of tlu' dendrites — The relation of the dendrites to the I'ell liody — Aden-
drilic neurones — Lateral huds or yemmules.
It is iiecossarv to oxiiiniiio a little more closely into the iiior-
pholojjical cliafaeteristies of the individual neiii'ones. Neu-
rones aiv in reality nothinjj more nor less than cells. They are
ctiriotisly modified in structure and elahorately dilTerentiated
in function, hut are none the less {Genuine cells of the animal
l)()dy. It must he distinctly understood, however, that the
nerve c»dl includes not only the cell body (perikaryon of Foster
and Sherrinffton) * and its proto])lasmic processes, althou<,di
these tof^ether make up the nerve cell of nniny of the text^
hooks, hut also the axis-cylimler process with all its subdivisions,
collaterals, and terminal ramifications. According to our mod-
ern definitioti, each and every portion of a neurone re])resent8
an inteirral part of a single body cell.-f. As will be eni])hasized
later, this view becomes of es])ecial significance in the considera-
tion of neurones in their physiological itiul pathological re-
lations.
Neurones being cells of the body just as are liver cells or
muscle cells, we should, notwithstanding their rennirkable
* A Tcxt.-Mook of Physiology, hy M. Foster, assisted by (". S. Sherrin^-
fon, 7th ed.. I'art III. The Central Nervous System, Loud.. 18!t7. pp. 915-
l',»r)'2, Mvo.
•)• The view expressed here seems to me to be lojjical. Some writers. T
think, ratlier too sharply separate tlie axis-cylinder process as an entity
apart from the rest of the nerve cell,
(id
TIIK KXTKKXAIi MOUIMlOLOdY OF NKl'KoNKS.
♦57
mornliolofiiciil ditrcrciitiiitioii coriospondin}; t»i the hij;li ])lijsi<)-
lofjiciil t'liiictions for which they arc (U'stincd, I'xiK'ct thciii to
|»(iss('ss ccrtiiin general chiiractcristics coninioii to all liviiij^
cells. And in this cxpctttatioii wo arc not (lisappointcd. A
nerve cell, like all others, ))ossesses |)r()toplasiii and nucleus, the
morphological characteristics of which, so far as they can at
present bo unruvck'd with the hijjhost ])owers of tin- microscope,
would scarcely secju to dilTer sutliciently from those of the ele-
ments of less noi)le tissues to acci'Uiit for their jrreater dij^^nity
of fuiu'tion.* It maybe that, alt houj;!! the iiM(M'osco})e or th«
human eye will never be able to distinjjuish sucu morpholo«;ical
dilTerenees, chemical methods nuiy enable us to arrive at much
more satisfactory results. Despite this .act, however, thanks
to some recent delicate histological methods, we are iu)W in ji
position to nuike certain definite statements concerniufi the ex-
ternal and internal structure of difTerent kinds of nerve cells.
In (liscnssinjj the structure of the neurones, it will be con-
venient to speak tirst of the extermil morpholo^^ical relations,
best revealed by the methods of (iol<j;i and Khrlich, and second-
ly of the internal arehiteeture of the neurone, our knowledge
of which has been much iiu-reased since the introduction of the
newer cytolo<;ical techni(jue, and especially from the ap])lication
of the methods of Xissl, Held, and Apathy. I have already
spoken of the remarkable uniformity in type of the nerve cells
in the most diverse parts of tin; central nervous system, atid by
my endeavors to emphasize this uniformity for the purpose at
that moment in view soiiu' perhaps have been led to infer that
the neurones are everywhere so similar as to be prav.'tically indis-
tinj]^uishable from one another. This is by no means the case ;
ijuleed, the method of (iolfjji has revealed a wealth of morpho-
lo<(ieal peculiarities of whicdi we were formerly able to obtain
♦ It may be that witli a wider view the difTerenees in " difjiiity " of \\w,
(lifTercnt cells of tlic body would become minimal ; tml it is hard fur hiimai)
l)('iti<i;s. so near their own eells, to coneeive of the superficial epiithclial cells
of the skin shed in larf:;e numbers daily in the wear and tear of life as beiiij;
of as hifi;h a >jrade as the eells which eonstruet a poem, or the perm cells,
notwithstaiidinfr the fact that einbryoloj^y teaches (I) that the nerve cells
are derived from the same f;erm layer that fj;ives rise to the ei)idermis. and
('i) that in all proliability every cell of the liody has within it. thou.irh latent,
sidistanees endowed with the jiroperties aiwl potential eiierLcy which under
sui
tab
oiulil
ions woi
dd make it capable of (level
lo})in;,' into a complete
?
'M
\'l
.1'-.
•f
I
■k'
/
i>t
human iieinir.
«;h
TIIK NKUVors SYSTKM.
'I*
■ J
:
I.
110 il<)«'«|ll!lt(' COIKM'ptioll. TIlC IMI'tlKxl of \ jssl t (K) llJIS rcVCUlciI
(lilTcrciicos of iiitcrrijil .structiiri! ol (liU'crciit cell jfroiips wliicli
iirc i'(|iial ill iinportiincc for [jiirposcs of cliissiliciitioii to tlio ex-
tcniiil form rchitioiis discovored witli (iolj^i's stain. Of tlicsti a
(Icscript ion is ^nvcwi furtlicr on.
TiuM-c arc many ncnroncs wliicii, from the apix-arancc of a
8inj,'i(' cxainplc staincti l)la(M\ with silvi-r, permit an al)soint(^ de-
cision as to their sourco. Thns we arc abU* at once to recog-
nize tlio (H'Us of the sensory fijanj^lia (Fijj. :U), the <^ells of I'ur-
kinjc in the cerehellnm (Ki<f. :5S), the pyratni<hd cells of the
cenOtral cortex (Kij^. :}T), and certain of the cells of the hippo-
eampns. The shape and size of the cell hody, the nund)er, siz(%
and mode of hranehinj^ of the protoplasmic and axis-cylinder
processes, the relations of these to the cell hody and to one
another are some of the criteria whi(di serve to <i;uide one in
makinj? a distinction. A laudable beginninjf has been made to
determine by the exact methods of reconstruction from serial
Kid. :{]. — S|(iiiiil KiOiKliiiii 111" a iicwliDrii wliitc inoiisc. </. r., dorsiil rout ; v. r.,
vciitr.il root; ». pn-., iicriplici-iil iutvc. uVI'tcr van (Ifliiiclitcii.)
sections the precise external morphology of tlu^ nerve (jells.
We refer to the beautifnl models of the r(>constrncted ' nerve
fjell exhibited i)y (J. Mann at the sixty-sixth meeting of the
British Association for the Advancennait of Science at Liver-
TIIK KXTKHNAI, MoHIMIolJXiV ol' Ni:i|{(»NKS. <;<«
|i*)(il ill IH'.H), iiiid at tlic iMcctiii^' ni' the Aiiiiloiiiisclic (icsi*U-
Hcliiift, ill Kiel ill IS!)H.
Tlic ImkMcs (tf the jicrvc cells viirv iiiucli in size, inciisuriiif,'"
lidiii tour to a liiiiuirctl and lliirtv-livc inin'oiis aiiti niorc in
Fl<i. ;W. — Mdliir (ill of vciitiiil lioni <>fs|iiiiul (did IVom llic liiiiiiiin I'trtus, tliirly
(•(•iitimctrcs lipiij,'. (Mt'tiiiid nf (iulKi ; al'lcr vmi l^cniupssrk. )
(liaiiu'tcr. Ainontf the vcm'v small ones arc the <:raniil('s of tlio
olfactory hulb and the small cells of the cerehelliini, whereas
the relatively huge iirotoplasmic masses, such as the larf^er cells
of the ventral horns of the gray matter of the spinal cord and
the spinal ganglia, or the cells of Purkinje in the cerebellum,
are visible even to the naked eye. Starting originally as spheri-
cal germinal cells, the cell bodies, jiartly owing to the mode of
origin of their processes, partly for reasons at present not clear,
later assume, in dilferent regions, very different shapes. The
spherical s])inal ganglion cell, the flask-sha]>e<l Pui'kinje cell,
the multi])olar ganglion cell of the ventral horns of the spinal
cord (Fig. ;?::*), the pyramidal cell in the (lerebral cortex (Kig.
'■V.]), the spindle-shaped cell of certain regions are well-known
and characteristic types.
%i
'I!
r<»
TlIK NKRVors SYSTKM.
Of t.
tlif cell
li i '
^
Fii!. :?:?.—
cortt'X
Oyul.)
lie two main viirictics of processes which c(»nie off from
hotly, the protophistiiie iiiul the a.\is-cyliii(h'r processes,
the foriiier, us iiii^ht he inferred
from thoir name, resemhU^ more
closely in appearance the coll
hody itself. 'IMiese protoplasmic
processes or, as they have heen
hetter named hy His, dendrites
{Ih'H(lrilcn), after their manner
of hranchin*;, represent, as u rnle,
rather coarse projections of the
protoplasm, which run out often
in several dire -tions from the
general mass of j)r()toplasm of
the cell hody.
liroad an<l thick, usually, \i^
their ori<;in, they <^row ^'radually
more narrow as they divide in a
dendritic or antlcrlike fashion,
until tlie final suhdivisions of a
single dendrite nuiy he distrih-
uted at a distance from the cell
over a territory of no ineonsider-
ahle extent. All the suhdivisions
of a single dendrite finally run
out to eiul free, never, so far as
our present knowledge goes (witii
the e.\cei)tion of a few rare in-
stances), aiuistomosing with one
another, iu)r hecoming united in
any way other than hy simple
contact (Kumon y Ciijal), hy
concrescence (Held), or hy cell
hridges aiul minute tihrilhe ( Aju'i-
thy), with the processes of other
neurones.* Xhe indiviilual den-
drites, Jiot only of different cells,
rynuiiidiii ctii of ccnhnii hut also of the Same cell, may
of iiiousi'. ( Al'tcr liiiiuon y ., ,, . , ,,
vary consulerahly in length.
W
* As van Gehiiehten forcibly jnits it. " Notez t)ien que jedis : (hiiis letat
actuel de DOS coiinaissancos'. los m'uroiics soiit des I'li'iiionts iiid('])('ii(laiits;
TIIK KXTKUNAL M()I{IMI(U<(UJY (»F NKlMtONKS.
71
While ill some types of cells all the protoplasmic processes are
approximately e(nially developed, in other types — for example,
in the pyramiihil cell of the eerehral cortex — oiio <le!idrite may
be eiiornioiisly dcvelopi'd, heiiij^ thick at its origin and exteiid-
in<x for a loii^ distance trom the cell hody, while the otiiers aro
dimiiiiitivc and comparatively insi},Miilicaiit in si/e and extent.
The contour of a (h'lidrite is often irre<;jdar ratlier than smootii
and sharj)ly detined. There may he nodidar s\vellm<js ( Kij;. ;{4)
at various points, thou<,di whether these are to l)e considered as
normal appearances, as artefacts, or as patholoj^ical plienoineiia,
does not yet seem entirely clear. There is, as a rule, no marked
Fl(i. !?t. — Miiltiiioliir iicrv II fnitii tlic ciml of llic ("inliryo cmII' slmwiiia Viiri-
cosilii'S lit" tllr (li'liil riles. I After Villi (ieluicliteli. )
nodulatioii in normal specimens. Herklcy, Monti, and others
have observed marked distortions of the dendrites in certain
patholojrical conditions. These will he referred to a^aiii in
Section V.
The course of the dendrites, though sometimes tolerably
8trai>;bt, is usually devious ; in fact, the irre<,nilarities in con-
tour and direction are ini[)ortant distin<;uishin<; characteristics
of this type of process. The character of the dendritic branch-
iiifi: of the |iroto])lasmic process varies much in cells of ditl'erent
parts of the central nervous system ; whereas in some dendrites
eolu vcut (lire qu'avoe Ics inetliodos irinvestifjution (Imit nous (tis|i(is<)iis
actiielleinoiit, on no voit pas de ooiitiiiiiito, on no voit piis (raiiastoiiidse.s
entro los eloinonts iiorveiix. et par cinisoiiuont on no doit pas los aiiiiiottro."
Hut this rule, as wo liave soon, is rolativo. not absolute.
< t
\l
mi
It 1
?2
•|-|IK NKIiVolS SVSTKM.
I
' ?
llic Itrimcliinf; cotiimcnccs lit ii sliorl distimcc from flicir orij^in
lit llu' nerve cell iiiid eoiiliiuies more or less rejiiihirlv mitil tlie
iiii.-il tlivisions (leciir, in the deinlrites iif otlier cells ii iii:iiii
IriiiiU iiiiiv csteiid tor ii coiisideralile distiiiice Troin the cell iiiid
tlieii siidth'iilv hreiik up into ii l;ir<j;-e niimher ol' teniuniil deii-
drilicjdiy Itrjincliini: processes. 'The latter liehavi(>r is ehar-
acti'ristie, for example, of the apical th-iidrites of the pyramidal
cells of the ceri'liral coi'tex. 'I'he dejirree of complexity td' the
briinchinj; varies I'lionnoiisly ; in some cells the dendrites are
toleriihly simple and luil little hi'anched ; in others, the hranch-
in<j is most complex.
The territory occupied Ity t hese ant lerlike divisions of the
nei've cell may, as has heeii said, he very considerahle. There
arc few fjreat or surprises for the student in histolo>;y than his
first view of a successful impi'ciznat ion with the silver method
of the dendrites of the rmkinje cells crowdin>; with their dense
felt work the outer layer of the cerehellar cortex. The hunt'
proloi)lasinic trunks coiniiiii' idV from the Hask-shaped cell divide
and suhdividc with tropical luxuriance into widespread hiishlike
masses, occupying a wide territory and increasintf the surface
of the cell iiody, perhaps a hundred times or more. The sii:;-
iiiticiiiice of this cerehellar forest, as it has hecn calhd, of tl.'ii-
drites luiist l>c very ,u;reat, hut it has never as vet hecn .-lalis-
I'lU'torily explained; al present, we can f(triii only hypotheses,
lit hest very nnsat isfactory, as to its mi'iininj;.
\'ery characterist ic, too, for the dilTercnt varieties of neu-
rones is the relation of the dendrites to the surface of the cell
body. Ill some instances, as in the motor cells »d' the ventral
horns, they radiate out in all directions from nearly every re-
jrioii of the cell surface. In the cells of the hippocam|)US, or
horn (d" Animoii, one <ir two dendrites proceed from one end »d'
the more or less ohloni;- or fusiform cell liody,and a whole ^'roiip
of them are <iiven olV from the other end, while the sides of the
cell body are smooth and soinctimes _u;ive oW no dendrites at all
(Fi<f. '.\i)). Other cell liodics, as is the case with some h(don<iiiij(
to the nucleus dentiitus eerehelli, yield dendrites from only oiu'
side. Ill the pyramidal cidl of the cerehral cortt'X the main
dendrite is ^nveii oil' from the apex of the pyramid, while the
smalU'r lateral dendrites are yielded mainly hy the an<;les at the
hase, the lateral surfaces and the hasal surface itself niviiiir oil',
as a rule, wry few or no dendritic proji'ctions at all. .Many
»^
'i^iii
TIIK KXTHHNAI/ MOWIMIOLOOV OF NKri{(»NKS.
«•>
(tlluT fxamplcs iiii;j:lit lie ;j;iv('ii, Inil tliDSc iiiciil ioiird will siillicc
to illiistnitc tlic iiiiportimcc of tlic orijfiii, ihiiuIkt, mid dislriltii-
tioii of tlic dt'iidrilcs iis fai-tors in dctcniiiiiiiiij: tlic inorpbo-
io^Mcjil clmraclcristics of :i },mv('Ii iiciironc.
The occiirri'iicc of cell hodics nitirrly devoid of dendrites,
tlie s(M;dled adi'udritie neurones, has to lie roco^Miizcd. Indeed,
Flii. :tr>,- Ni'lll'iiiii'S ri'iiiu llic liiiiiKiciMninis (lioni of AiMiiKiiil ul' :i pii|i|iy two
(liiys iilil. (Al'lcr l-'iillikiT. ) 'Two ityniinidiil cells ((iiil^i^ cill.s of 'r.vpc I)
:iiiil (II II' fiisifonii (I'll (( iol^i's rcll of 'ry|ii' III mi'c shown.
in invcrtobrat.i's, as von Leiiliossek, Ketzius, and A|i;'illiy have
sliowii, th(>y arc very niiinerous and form in these aninnils no
small proportion of the eonstitnents of the nervous system. In
sneli neurones, however, the pyriform stem process shows near
the cell many accessory liranchin<j:s ( l*'i<x. IJii), which some he-
lit've to lie of the nature of dendrites, thou<;h others look upon
them as collaterals. The ultimate continuation of the main
process is rci^arded hy all as the axis-cylinder process of t he cell.
■:n
f I
i I
IfV
.,*;|N
THE XERVOUS SYSTEM.
t t
T\w qiiostioii liiis been fully (iiscusscd hv von Lonlioss('k (np.
cif., S. S4 rt'.). In tlio iidult luimun uorvous system the nia-
Fi(i. 3(5.^Uiiil)(iliir ct'll from a ffimKl'"" "'" Linuliiicns. (Al'tcr vi«;i Lt"iili(>ss('k.)
The roll Idxly is dt'Viiid ol' ilciidritcs ; the iicci'ssory hmii'. iit'S ol' the iiiaili
prncfssfs arc l()()k('<l ii|iini by .simic as (Iciidritcs, l>y otiicrs as collatcr.ils.
jority of the neurones of the ganglia of the dorsal roots are
histologically adendritic ; * though embryologically, and per-
in
J.
Fl(i. :{". — l'liii'iiiiii(iiiyiM|ili lit' a iiiiriiial |iyraiiiiilal cell (Vniii the cfTcln'al cortex
of tlic ;;iiinca-|)iK. (After I'.cikU'y. ) The siiifjlc-liraiu'licd apical dendrite
and tlie liasii deiiilrites show distinctly the lateral hiids or "Kcniniujcs."
The axom- is relatively smooth.
♦ Denclrilos hiive. Iiowever, been deinonstratod upon certain of the cells
within the spinal jjanj,'liu.
f-
THE KXTKRNAL MORPHOLOGY OF NEUIIOXRS.
75
haps also physiologically, the axone of the periplionil sojisory
nerve fibre is more of the nature of a dendrite. Microseopie-
ally, however, it has every appearance of an axis-cylinder pro-
cess, and indeed must be regarded as the axis cylinder of a
meduUated nerve fibre. The dendrites within the central nerv-
ous system are, like the cell bodies, entirely devoid of myelin
sheaths.
Another feature characteristic of the dendrites of some
nerve cells deserves more than passing notice. Upon the sur-
Fui. 3S. — I'lmtoinicrKKrapli olii iKunial I'urkiiijc cell t'nnn the Imiimii ('crcliclliir
cortex. (Alt<T !'.ciklcy.)
face of the processes it is possible to make out minute lateral
Inids, which, although too small })ei'haps to deserve the name of
branches, are still definite histological structures, probably of
no mean significance. On the dendrites of the pyramidal cells
(Kig. :}7) of the cerebral cortex and upon those of the I'urkinje
cells in the cerebellum (Fig. .'5S) these lateral projections are
very numerous and constant in silver preparations of healthy
tissue. They are not unlike the projei^tions into the liver cells
from the bile ca])illarie8, as revealed by (Jolgi's method, but ajv
:HMl
w
7()
TIIF. NEKVOrs SYSTEM.
pciir in fiir jrroiitor iiunihcrs. Hcrklcy, wlio has niimed tliosc
processes " gt'inniulcs," * tliiiiks tliey arc of \ery jjjri'iit sijfiiifi-
cuiuc for tlie contact of different neurones witli one another
(Fig. ;{!»), and thus for the transference of inijiulses from neii-
ISf
If
I
! i «l I:,:
:ii -! I
Vic. 3!t. — riiiitdiiiicniKniiili ot' llic iipical (Iciiiirilc of a laiffc iiyrainidal cell nf
I lie rcrc)>ral (•(irl<'.\ sliiiwiii}; llif arniiijjEt'iiiciit of tlic lalcr.il liiidsor kciiiiiiuIcs.
(Alter Hcrklcy.)
rone to neurone. lie ass(M'ts that in (tertain disesises, particu-
hirly in certain intoxications, it is these " geniniulos " which
are the portions of the neurone which tirst suffer, and lie has
even sujf.irested that in paralytic dementia, for example, the
early symptoms may be explicahle by assuming the destruction
of large numbers of these gemmules.
It has bee)i objected that these lateral buds are demonstra-
ble oJily by (iolgi's methods, and that therefore one should
hesitate before deciding that they are more than artefacts.
* The selection (if the term " f^eiiiiiiules " to desifjiiate these lateral buds
is tint entirely free from olijeetioii, iiiasmiieli as the same word was n^,•d liy
Darwin in coiineetion with heredity as ti name for the minule elements
which, aeeordiiif; 1,0 his theory of pangenesis, are {fivon ofT by the cells in
dill'ereiil ])urts of the body, to be taken up later l)y tlie sexual cells.
,'!!!
THE KXTKIlXAIi M()IllMI()Ii(>(}Y OF'' N'KUUON'KS.
I I
Hill * liiis recently stutcMJ that, iiltliout^li he tiiids tlieiii in iiini!
cases out of ten, lie believes tlieiii to be artefacts represent ini^
"the cell end of an nnstaiinible nerve filament surrounded by a
film of stainini^ cell plasm." From the constancy of their ap-
pearance on the dendrites of certain only of the nerve cells,
from their entire absence from those of certain others, and from
the fact that they are most apparent and more shar|)ly defined
in the most suceessful impre<fnations, it seems, however, fair to
conclude tJiat they are definite histoloj^ical structures. More-
over, Hanion y ("ajal f has l)een able to demonstrate beautifully
these lateral buds on the dendrites of the pyramidal cells of tlm
cerebral corte.x by means of the " vital stainin<f " with methy-
lene blue, and has ])ictured them in Fiijf. 1, a, of his article.
I'hese appearances can, therefore, l)e no aci-ident, but whetluM'
the interj)retations thus far advanced as to their si<fniH<'am;t!
are correct or not further knowU'djjje and experience must de-
termine.
* Hill, .\. Note OH "thorns" ami n thi'ory of llit> constitiitioii ol" j^niy
inatttT. Hiiiiii. Loud., vol. xx, lHi»7, pp. l:it-i:{7.
f Haiiioii y Cajal, S. Las Kspinas ColatiTalcs dc las ('('■liilas eld CiTcbro
'IVfiidas por I'l .\/'il de Mt-tilciio. Uevista 'I'limcstiai Micro-rriiflna, .Madrid,
vol. i, fuse. 3 y :5, Agost'), IBiXi, pp. TilJ-CiG.
i
^
ill
C IT A ITER VIII.
li: KXTKHVAL FORM Ol' TIIK A X IS-CYLIXDER PROf'KSSES
OK AXONKS.
II
Theaxis-cyliixlor processes cr axoiies — Differential (■haraeteristifs of den-
drites and axones — 'Die relations of tlie axones to tluM'eli bod_, F)en-
(iraxones and Inaxoiics — Monaxones — Diaxones- — I'oiyaxoncs — Anax-
ones — Seliizaxones — Modes of termination of axones — 'I'ciodendrions —
The coverings of axones.
TiiK iixis-eylindcr processes or axones * of nerve cells differ
markedly in many ways from the dendrites. The appearances
presented by an axone in (ioljji preparations are so characteris-
tic that after a little experience the observer will rarely have
the slightest difficulty in distiiifiuishing it from adjacent den-
drites ; indeed, a few days' study with the microscope of
successfully impregnated specimens will do more to convince
the student of the differences in type of dendrites and axones
tiian will numy pages of carefid explanation. f On analysis,
however, the structures admit of differentiative description.
The axone differs from the dendrite in its mode of origin from
the cell body, in its contour and calibre, and in its course and
mode of branching; further, if long, it is usually niediiUated,
and also shows differences in its access- ry processes and in its
method of termination.
.Arising embryologically through a prolongation of the stem
of the pear-sha])ed neuroblast {riilv iiifni), in the adult the ax-
one conies off" from the cell body or from a deiulrite (Fig. 40),
in the latter case usually near the cell body, though sometimes
at a long distance from it, by a narrow wedge-shaped beginning.
* KiiJliker's Netiraxon is well shorteni'd to tlie more simple nxohe, a term
convenient and not liiiely to lead to any confusion. The designation ui'itrite
has also lu'cn applied to this process.
t It must in." Mdmittc<l. iiowcvcr, that in certain regions — for example, in
the sympathetic ganglia and inthe plexuses of Meissneraiid Am'rhaeh — the
dendrites and axones nuiy rescnililc oni' another so closely that they can
only with considerable ditliculty be distinguished from one another.
78
Vr i:
TIIK KXTEUNAL MOUl'IlOljOOV (iK NHUUONES.
ro
'Phis mode of orij,nii iiiakcs tlu!
iixniic nppwir t(» be a mort' iiido-
|H'ii(U'nt structure tlian the den-
drite, since the hitter, as is
(ihvious from its broad, wedj^e-
sha])t'd orijrin and from tlie
nature of its contents, is sim-
|ily an attenuated portion of
tiie body of the lu'rve cell. That
the axone is, however, also a di-
rect ('(tntinuation of the proto-
plasm of the cell body, at least
of the ground substan(!e of that
protoplasm, there can be no
doubt, although, as will be point-
ed out later, certain substances,
those which account in tissues
fixed in alcohol for the so-called
Nissl bodies, present in consider-
able amount within the cell body
and dendrites, appear to be en-
tirely absent from the axones, or
to be present in them in such
small ((uantities as to escape de-
tection by the methods at
present employed for demon-
strating them.
The calibre of the axones
varies much for the dif-
ferent cells, correspond-
ing in general to the length of
their course, a point which
Schwalbe early pointed out
and which von Lenhossek fki. lo.— Ncuidnc fVnm the uiiiii- lohc of
, ,, 1 • 1 IT. tlif I'liilirv" cliick. (AfttT Kc'lllikci'. )
has recently emphasized. I n- .,,,„. ,,,,jj,. ,i,,„,,,it,. ,.„„„{„;; towuni tiu-
like that of the dendrite, its
calibre is, as a rule, main-
tained for a considerable dis-
tance from the cell. Kven
in the deiulraxones ((Jolgi's cell. Type II; Kolliker's Ncurn-
podivn) the axone is sulticiently well characterized in this
piTiiilicry ol' till' IuIh' ^ivis rise tn an
axone. u. wliicli runs toward tlic ccii-
trc. KivinK oil' in its conrsc Sfvcnil
collalcnils. One of these, c, is nnu'li
liranehed.
/i
1
<'
l>
■
' t
\\
i
i
r
r
so
TiiH \krvol:s system.
1
1 |i
, ■!
f,
lit
\ 1
!jii
1 1 ■ 3Ji '
m
li
; I
respect to permit easily of its ideiititicatioti (Fij?. 41). Wo are
often deceived from its narrow calibre as to the volume of ati
axis cylinder. 'IMiis may l)e as much as a hundred and eij^hty-
sevon times that of tlie cell l)o(ly (Donaldson).
Fl(i. 41. — Oiiljii's cell III' Type 11 I'rom llit' dorsiil horn of the tiny matter of tlie
sjiiiiiil conl of the iicwliorii inoiisc. (Aft<'r voii liCiiliossc'k. ) Kvcii in siicli a
(Icndnixonc llicaxonc is very easily distinKiiislialile from the tlendrites. Thu
latter are oidy represented in part in the ilinsti-ation.
The surface of the axono is smooth, its contour regnhir, tmd
its course, :is a rule, direct, so thtit in most instances the trained
eye can recognize it intiolgi preparations at first glance stand-
ing out sharply like ii piece of hhu^k- thread on a white or yel-
lowish l)a(!kground. The axones do not always, however, take
the course to their destination which appears to be the shortest,
In
hi»i
fr
! I I
■If
Till': HXTKKN'AIi M()I{IMI()L()(iY OF Mll'UONKS.
81
aiul the <)ri<fiii and sij^Tiiiicanct' of some ot' the curves and
di<;ivssions, for example of the root tihri's of tlir iicrviis facia-
lis, art' dillicult to uiidi'rstaiid.
'riic Iciijrtli of the axoiios is in tiic liijrlicst dcfrrcc vari,'il)l('.
lu the dondraxuiit'8, wlicre dendritic brandling of liiu axonu
Fid. l~. — Spcciiil cells ( ]i(il.Viix(iii('s) iif lunlcciilar liiyir (if ((nliiiil cMirtcx of a (l(i«
line liny iild. ( Aflcr l»iiiiic'>ii y Cajal. ) .1. riisil'iiiiii cell ; />'. liiaiiKiilar I'cll ;
r, aiKptiiir riisiloriii imII ; />. |i(p|yKimal cell w itii iiiiiiicniiis dcii'lrilcs and an
llMiiic which divhh's rciicalcdly ; c, axoncs.
occurs soon after its de])artnre from the cell, the total leufrth
before c()in])lete loss of individuality may amount to only a few
millimetres, or even to a fraction of one millimetre. On the
other hand, the axoncs of some of the motor neurones are fully
half as long as the height of a man. Hetween these two ex-
tremes there is every possible degree of variation.
The neurones with long axoiu-s (iuaxones of von Lenhossek,
(iolgi's cells of Tyjte I, KoUikerV' /ifffroptx/fir ycrrciizi'llcH),
as a rule, are monaxones — that is, they possess only one axone,
Fi(i. 43. — Rjimon y Cajal's cell fioni tlic siiju'rHcial layer of the cerehnil cortex of
a lo'tai cat. (.U'tcr Ketzitis. ) n. cell liody ; h. deiidrite : c. axone.s.
though the spinal ganglion cells may, histologically at least {vide
Kvp7'(i), he regarded as diaxoJies. There are neurones, too,
which possess several axoncs. Among these, the so-called ])oly-
axones, are the cells described by Ramon y ("ajal in the outer
luyer of the cerebral cortex of certain animals (Figs. 4'^ and 43),
from the horizontal dendrites of which as many as four or even
7
', <
/i
n
m
!(::«
(I
82
THE NKUVOUS SYSTEM.
Hi
i I!
II
I ■
i|
!l;
'T . * St -
f-- . -■=
- -t r .-
more hniiiflicri niiiy h{> {jivcii olT which
possess all the cxtcnml chariictcrs of
delicate uxoiies. Aeconliii},' to Uaiiinii
y C'ajal, many of the syiupatlietic ^'aii-
<,'lioii cells hiid down in the viscera —
for exainple, those of Auerhach's and
Mcissncr's plexuses — possess several
axones.
Anax( Mes, neurones whieli appear
to he ahsolutely devoid of axis-cylinder
processes, occur in the nuclear layer of
the olfactory hull), in the retina ( Ki^.
44) {ffUvIvs ttiiKicri/irs of Ramon y
Cajal), and, as von liechterew has
pointed out, within the haskets of the
Ki(
. 45. — Aiiaxoiic Croin tlio basinet of a Piirkiiijc
cell (if the (■(•rclicUar corlcx. (Mctlmd nf
(idljii ; after vim lici'litcrcw. )
Purkinje cells of the cerehellum (Fig.
45).
To axones which in their course
divide into two equal or nearly e(|ual
hraJiches — for example, the Y-shaped
divisions of the central axones of
peripheral sensory neurones after their
entrance into the central nervous sys-
tem — the name of schizaxones has
lieen applied (Fig. 4(1).
The ultimate terminals (teloden-
drions) of the axones have been care-
fully and exactly studied in great num-
bers of instances, and nearly all observ-
ers agree that, as far as ciin be made
out by the method of Ci olgi, every axone
TIIK EXTKKNAL M()UIMI()Ii(KiY OF NKl'UON'ES.
83
invuriiibly ends "free." Tlu' tcriniimtioii of a l)rancli of an
uxono by mt'un.s of ii doliiiitt' I'lid arlxtrizjition iibout ti siiifjlo
cell ( Fijr. IT) ociciirs, tlioujrb
not so t'r('(|U('iitly iis iiumy
writers would Iciid oiic to
think. The coninioii inodo
of ciidinj^ is by exhaustion
throii;,di inidtiple division,
tliis division iieinj^ often
spread over (juite a wide
Fic). 4(1.
Fio. 47.
Fl(>. 4<i. — Y-siiiiiH'(l division nf scnsury rout (iUrcs after cntrMiict' into tlic spinal
(•(inl. Six-nioiiths liiiniaii I'nilnyo. (Alter vuu Kiilliker. 1 Axmies wliicli
iinderK'i siicli a division are talietl liy von I.enliosseU s<-lii/.a.\oM(s.
Fio, 47. — Hnd i-ainilications torniiii;.' a liaslselwortc alnnit two I'lirlvin.jc cells of
the (•erel)ellar cortex. (From .Sdiiil'er, after lianion y Cajal.) «, axone ; b,
l>askctwork.
domain, so that the terniintd ])ranehcs of a single axone not
infre(|uently come into the neighborhood of the dendrites and
cell bodies of a considerable number of t.iJerent neurones.
It may not be superfluous to emphasize this fact, inasmuch as
a great nuiny diagrams hitherto pul)lished in text-books and not
a few descriptive articles are entirely misleading ; the intimate
interdigitation or interweaving of the terminals of one axone
exclusively with the dendrites of a second neurone, so frequently
pictured, very rtirely occurs, except in a few localities, as, for
instance, in the olfactory glomeruli of some aninnds (Fig. 48).
It is much nearer the truth to think of one neurone coming by
means of the terminals of its axone or axones into contact with,
'(.
Ii /A
^ m
t
vj
m
im
<
I,!
1 1'
li'"
84
TIIH NHUVOl'S SVsrKM.
Fia. 4S, — Sclii'inc sluiwiiif; tlic relations in tlu' olfiictiiry ;;linii('nili tit" tlic axones
III' the iiH'actciry nciirnnt's oftlu' lirsl order to tlie (len(lrile> of tlie mitral cells
ill liinls
After van (iehucliten.)
Fid. lit. — Nucleus of termination of the sensory jiart of tlie nerviis trijreminus of
the cat. (.\fter Meld.
'I'lie end ramidcatioiis ol' tlie sinjile axis cylinders
are s<'en to he distriliiileil in widely separaled areas, so iliat impnlses coining
alou}.' I
lihre to the nindeus may come in contact with a larf;e nuuiher
i)f neurones of tin
mil order.
scril)0(l ill various parts of the central nervous system. One of
tlie most interesting of these is that shown in Fig. 53, which
TlIK lOXTKUNAL M<>UIMI()L(»(iY (>K NKlUoNHS.
H5
illiistrult's tlic iiKxlt' of termination of the so-called '• (•liinl)inj^
lil)res"iii the cerelu'llar cortex. Many otlier modes of termi-
nation — for exam])le, tlio diselikt' expansions to I)e seen in
Fi(i. 50. — A imu'li-l)niiiclif(l lilirc IVdiii the optic thiilamus of a mouse. (After
Kollikcr.)
Meissner's corpuscles and in the tactile discs in epithelial sur-
faces (Fig. o;{) — might he mentioned. The curious calyxlike
terminals (Held) of axones met with in the nucleus corporis
trapezoidei are fully described and pictured in a subsequent
i
r
1V
ih
■ivqi
i
Hti
TllK NERVOUS SVSTKM.
chapter (Soctioii \'I). It is to bo reiiiomluM'od that witliin the
rentnil jhtvous system the tt'rniiiials of tlio axoiu's and collat-
erals may, in some iustancos, como in direct coiita(^t with the
bodies of other neurones [ride Fij^. 47), in other instani-es the
second neurones are inlluenced perhaps maiidy throujjh their
jirooesses. Tlie anatomical relation of one nerve cell with an-
other is spoken of by Foster . ul SherringtoJi * as a sifiKijisis. f
s *
•[
Fid. T)!. — 'riircc end iirlidrizMtioiis of ii|ilic libvcs rnnii tliooptii' loin- of an I'Ui
lir.vi) cliick. (Al'tcr Riillikcr. )
In the majority, althou<fh not all, of the inaxones the axis-
cylinder processes are in the greater part oi theic course inclosed
within a slieatli. Dendraxones, beini; for the most part entirely
witliin tlie <^ray matter of the cehtnil nervous system, i><)ssess
axoual processes which are, as a rule, devoid of such a pro-
tective covering. In the majority of peripheral spinal and
cerebral nerves this covering consists of a relatively thick fatty
layer fortning tlie myelin sheath, external to which is a cellular
layer, the muirilemma. Ilenle's sheath is the librous tissue
^
* Op. cif., p. i&l
f l-'roiii crvv and Hwrw, i-liisp.
TIIK KXTKKXAI. MOHIMIOLOCY OK XHrUONKS.
ST
often present external to tlu' neurilenuna. Witliin the central
nervous system the myelin sheath is present, but the neurilemma
appears to be absent, a fact which
sjjcaks stroiifjly in favor of the
view that the
myelin sliea
th is
the result of tlie productive ac-
tivity of the Hxone rather than of
the neurilemma eel
Is, as many
have believed. The symi)athetic
nerve tibres
possess no myelin
sheath, but are surrouiuled by a
pr()teetin<( layer of lon^jf, flat cells
formiuff a sort of neurilemma.
It is not my ])urpose here to re-
fer in detail to tlie histolo«j:y of
these various sheaths of the ax-
one ; they have long been care-
fully studied, and are described
at length, and, as a rule, correct-
ly, in the text-books. I would
oidy point out that the discovery
of the fact that within the brain
aiul spinal cord the axones of
lu'uroiu's destiiu'd for dilTerent
functions receive their myelin sheatiis at ditl'erent periods in
developmental history, and its a})i»lication as a nieans of analy-
sis of nerve tracts form the basis of Klechsig's embryological
methods. liy means of the recent met hod introduced by
-Tlu' so-calli'il " cliiiiliiny
(if tilt' (•(■rtlicllar ciirtcx
IVitiii tile lir.iiii lira I'liilil :i iiuinlli
ami a hall' old. (Al'tcr K<>llik« r. )
111
m
, ..— t
' ■ ■
4^'
i
I
(
.. 1
•■} !
, ■ •■ '
t
Fl(i. TiH. — nisc-sliapi'd cxjiansiDiis on iicivc titirilln' of tlii' piK's siioiil and their
relation to ciTlain of tlii' ciiithelial cells. ( l''nini Sehiifer. after Itaiivier.)
)/. nerve tihre ; »i. meniscus or disc; n. epithelial cell in contact with di.sc ;
c, ordinary epithelial cell.
1
TT
88
THE NERVOUS SYSTEM.
Eye muscle
li!
I' ■
li
Fibre of
Rotator
muscle
of ttie Iwfid
Dorsttt Rvol
Dorsal funiculus
Reflex fiiilfi by way
ifqrsol \ \ 0/ llievenlral
horn I \ Commissure
( i-i*
Fki. 54. — Dcvcloiiiiifr niyt'liii sliciitlis (ifditrcrciit afii's as seen tlir<iti};li tlic jiolar-
i/.!iti<>ii inicn>sc(i|)c. Scliciiiatic. ' Al'lt r H. Ainltroiiii ii. H. Held, Aicli. I".
Aiiiit. II. I'liysiol.. .\iiat. Atitli., Lcip/... IsiiH, Tat'. i\.> Tlic upixTol' the (wo
(inures rt'prcsfiits till' rcllix |iatli lutwccii (lie acoustic aii<l ojitii' nerves and
tlic motor apiiaratus <,'<iveriiiiiK tlie nioveirieiits of tlic head anil eyes. The
lower (iKiire shows the reflex path tliroiifjh the dorsal and ventnil roots of
the spinal ord. Yellow tihres oldest ; red (il)res youngest.
' ii^'»
THE i:XTKHNAL MOUI'IIOI.OCJY OF NEURONES.
8i>
Anibroim and Hold,* in wliicli tho poliirizatioii microscope
permits the dctormiiuition of the younger and ohler of medul-
lated fibres of nearly the same age, the sphere of ap})lication
of the myelinization method of study has been consideraldy
widened. In Fig. r)4 the sharpness of analysis made possible by
means of the color dilferentiation is illustrated. Held f has
tested recently by means of the polarization method the effects,
of stimulation upon the progress of myelinization. The work
done upon these lines belongs to one of the most important
epochs in the development of methods of neurological investi-
gation, and to the application of Flechsig's method to the
study of some of the higher nerve centres I shall later take
occasion to ref The portion of an axone nearest the cell
body is with s^ i exceptions devoid of myelin, as are also
its terminal ramifications (motor end plates and naked telo-
dendrions within the central nervous system). Here and there
in its course a medullated peripheral nerve fibre may suddenly
lose its myelin sheath, be devoid of it for a certain distance,,
and again suddenly be covered by it (Schiefferdecker).
* Ambroiiii. II., uiid II. Held. MiMtriiKf /.<ir Kcniitniss ties Nerveninarks.
Ui'ber Kiitwickcluiij,' iind Mcdculiiiigdes Ncrvciiniarks; rduT noohachtuii-
gen an Ichondcn uiid I'risciifii .Xcrvciil'asom iind dii' Sichtljarkeit ilirer dop-
pplti'ii Contouiirmig. Arch. f. Anal. u. I'liy.'^iol., Anat. Abtli., Leipz., Jahrg.
(18!)(;), II. iii u. iv. S. 2()'2. 214.
f Hold. II. Uelicr expi'iinicntclli' Ucifung d(<s Ncrvonniarks. Arch. f.
Anat. u. Physiol., Anal. Al.lh., bi'ipz., .lahrg. (IHilO), II. iii u. iv. S. 223.
/j
CHAPTER IX.
ii
! R !;
H
C'OLLATKKALS, SIDE FIHUILS, AN I) INTKUXiaUOX AL SUBSTANCES.
Ai'ci'ssdi-y hnuu'hiiigp of the axonos — The coMntcrals or imraxones — The side
fibrils of (iolf^i — Siibstiincos belween neurones.
Besides tlie niiiiii divisions of uxoiies above described, tlie
accessory branchiiifjfs of the axones, the collaterals (von Len-
hossek's Parnxonen ; Retzius' ('i/h'/if/i'di/nniri/r/t), and side
fibrils ((^olifi) must be considered. In (Jolgi ])reparationa the
point of orifjin of a collateral from the axone is usually marked
by a slight thickeninjj. In the spinal cord, collaterals from the
fibres of the dorsal roots and from the fibres of the wliite
fasciculi run in at d liferent levels in jjreat numbers into the
white substance, so that a i;iven nerve fil)re may be connected
not only with the gray matter in which its axone finally tern)i-
nates, but accessorily by means of its collaterals with the gray
matter of very many segments of the cord intervening between
its origin and ultimate termination, a fact of iiu'alculable im-
portance in the explanation of roundabout coiuluctions and of
manifold reflex activities. According to von Lenhossi'k, and
my own studies thus far support his statement, tlie portion of
the axone nearest its cell of origin — that is, the cytoproximal
portion — possesses many more collaterals than that distant
from the cell body, indeed, the cytodistal portion of the axone
may ])e almost or entirely devoid of collaterals. Owing to
technical difiiculties, the number of collaterals Avliich mry be
given off l)y a single axone has never as yet been satisfactorily
determined. Kolliker, in a longitudinal section of the spinal
cord a few millimetres long, counted as many as nine collaterals
from oiu> fibre. It will be remembered that some of the fibres
of the dorsal roots in their intramedullary course extend from
the lumbar cord as far as the medulla oblongata, though it
would be incorrect to calculate the number of (collaterals pro
rri/ff, since, as has just been said, the cytodistal ])ortions of tlie
4ixone appear to be entirely free from accessory branchings.
!)0
-A.
■f.l
nil
THE EXTERNAL MoltlMIOLOdY OF NEL'UoXES.
\)l
\'(»ii Lciiliossck, wlio has made oxliaustivo studies of tlie spinal
eord, iiicludinj,' that of liuinaii beiiijxs (Fiji. 5,')), lias never ht-eii
able to find eolliitenils in the fasciculus gracilis (iolli and does
not believe that they exist there. Moreover, the munber of
collaterals varies much, not only for axones of the same fascicu-
lus, but also and more particularly I'or tiu' axones of ditl'erent
physiological systems. In the dorsal fasciculi of the spinal cord,
Flo. .^5. — Sclicinc showing' tli<' clinicnts nf the tir.\y matter (if tlic s])iiial curd.
Oil tlic Ift't arc sliiiw II tlic tiTiiiiiial axdiics and ('(illatcrals ciitiriii}; tlic Kiay
iiiatlir I'niiii tlic white siilislaiici' : on the rifilil arc to lie seen tlu' <lill'erciit
nerve cells (if the firay inalter. (After Von LenlKissc'k as iiiodilicd hy van
(iehuchteii. ) '(, ventral hdrii cells, the axdiics of wliiidi fjo i'lto the vent nil
roots (if the sjiinal nerves; fc. eidl, the axone of whieli iiasses into the dois;il
root of a s])iiial nerve ; c, c', <l. I. /), cells, the aNolics of which jiass to the fas-
ciculi of the white matter; c, hetcroineric nenroiies ; c'. hccatcroiiieric neu-
rone; (/, /. II, tantoineric neurones; (i, (!olj;i"s ctdl Tyjie II, or dcndraxoiie.
von Lenhossek has shown that the collatertds are most iibundiint
in the entry zone ; they are very numerous in the middle iind
ventrtil ptirts of the fiisciculus cuncatus Hunhu'lii, but occur in
much sniiiller numbers in its dorstil peripluM'til ptirt ; ami in the
fasciculus grticilis, tis has just been pointed out, they iip})ear to
be absent idtogether. Tiuit they are iibsent in the fasciculus
gracilis must not be taken to mean that these axones are en-
tirely deprived of collatertils, iuiismuch, as is well known, tho.se
belonging to the fibres constituting the fasciculus grticilis rep-
resent axones of dorstd root fibres, which lower down luive run
for some distance in the fasciculus cuneatus and only after a
iJp^
.-— -Tl
L'
.1 !
'J2
TIIK NERVOUS SYSTEM.
i u.
^ I
i
i
[i.
m
w.
loiijri'i' or shorter course witliin tlio cord liave passed over, or
have l)oei nslicd over tlirouirli tlie entrance of more fibres from
dorsal re lier up, into the fascicuhis (gracilis. Tluit there
are axoUv , vvever, which have no collaterals .seems very prol)-
iible, and this is true for
many axoncs of ventral horn
cells and of the optic and ol-
factory peripheral sen-
sory neurones.
The coUaterals are
often, it nii^fht perhaps
be said jrenerally, me-
; dullated, and an im-
mense number of the
very fine fibres revealed
by Weigert's method
within the gray matter of
the central system represent
medullated collaterals. A
great step forward was made
when it became possible to
recognize that the great mass
of medullated fibres passing
in from the dorsal funiculi
of the cord do not represent
the ternunal brandies of tlie
fibres of the dorsal roots, nor
even the main stems of tliese
fibres on their way through
the cord. The majority of
these fibres represent col-
laterals and are not nuiin
branches of dorsal root fil)res,
by far the majority of the
latter passing on up in the
dorsal funiculi. Thanks to
the extremely careful studies
of von Lenhossek, Ramon y Cajal, and K()lliker, whicli supple-
ment the embryological investigations of i-'lechsig, we are now
al)le to recognize very ditl'erent grou])s of these collaterals, in-
cluding the reflex collaterals and others, groups differing in.
Fui. 50. — Eiuliufis. <i, of collaterals t'nmi
tlic dorsal f'liiiiculi in the fjray matter
ol'tlie siiilial cord of the lie\v))orii nih-
l)it. (After Kcillikcr. )
a
I
>. !
!'l
THE EXTEKNAI. MOlJI'lloLOCiV ()F NKIMIOXI-X
!>8
orijrin, in tlii'ir nu'tliods of termination, anfl, most interesting
of all, i)rol)al)ly in function. This now classification is destined
to fjo far in ri-nderiiiir clearer the ])atln»loj:y of the s))inal cord
— indeed, it lia.s already done much to elucidate many obscure
problems connected therewith.
The free ending of the collaterals like that of the terminal
axones is insisted upon l)y those who work with the method of
(jiolgi (Fig. -')()). After repeated division each little fibril runs
out into a terminal end point which occasioiudly, though not
always, appears slightly knobbed. The collateral may thus
come in contact, by virtue of its end arborization, with the pro-
cesses of several other lunirones, and here as before the diagram-
matic representation of collaterals surrounding exclusively the
cell body or dendrites of a single neurone is to be emphasized
as misleading. V.'hile it can not be denied that such a means
of ending may occur, it is at least certain that it is not the
only one, nor, I think, the most common. The imj)ortance
of recognizing the real method of termination becomes more
obvious in the consideration of the simultaneous affection of
a whole series of neurones belonging to one
functiomd neurone grouj). As to Avhether col-
laterals can be distributed in domains in which
they can come into condu(!ti(m relation only
with the side fibrils or collaterals of <i.n>)/t'.s of
other neurones, I shall have something to say
when discussing the possible functions of the
different parts of the neurones.
(Jolgi distinguishes the side fibrils (Fig. 57),
which run off from the
axone into the gray mat-
ter imnu'diately after its
origin, from the regular
collaterals which arise at
a greater distance from
the cell body. The form-
er are non-medullated,
the latter usually medul-
lated. 1'hough morpho-
logically there seems to
he no very oljvious reason for such a divisi(m, von Lenhossek
has recently expressed himself as of the oi)inion that the two
A
Via. 57. — Side filiril of (ioljji on tlic axone of a
motor cell of the vciilriil horn of the spiniil
conl. Tlu' arrow indicates tlie ccilnlifnj.'al
(liicction. (AI'tcrvoM lAiiliossc'k. )
94
TIIH NKRVOrS SYSTEM.
1- '
: ( 1 ! (
structnros niiiy bo of ditfcrt'iit si-i^fiiticiiiico in tlioir fuiu'tional
aspects, ii siibjoi't to wliicli it will also he iicccssarv to return.
Ill sum, then, tlie cell body, <len(lrites, axoiies with their col-
laterals and telodeiulrions represent the (lillVreiit portions of
the neurones as discovered by tiie (iol<;i method. It is obvious
that the closer the analysis, the more certain and distinct l)c-
comes the view of the relative iiiorpholoj>-ical indi'iieiidenei' of
the nerve units. Kveii of the existence of ii solderinjj inter-
substance we have very little evidence of a com incinji' nature.
His assumes the presence of an unformed ground substance
between the ditferent jirocesses, and suggests that this may be
a constituent easily a tfected by intluences of a general nature,
especially those of nutrition. On the other hand, von Leiihos-
sek argues that no one has seen this intermediate cement sub-
stance, and believes that it is possible to get along with the
view wliicli looks upon the plasma stream or lymph stream as
the only substance saturating the final plexus of nerve processes
and filling ii[) the luiiiimal interspaces of the tissue, (hir
knowledge of the lymphatics of the central nervous system is,
however, deiilorably deficient, and there is urgent need for fur-
ther researcli in this direction.* Kanion y C'ajaTs f hypothesis,
according to which the penetration of neuroglia fibrils between
the processes of neighboring neurones plays a part in the make
and break of conduction paths, has as yet but little basis
dependent directly upon anatomical oliservation.
To lleld's views with regard to "concrescence" as a mode
of interneuronal relation we have already referred in Chapter
VI. In his third contribution to the structure of nerve cells
Held J mt'ntions that by means of (iolgi's metliod he has been
i
* CI'. liiiiswiuiger, O. iiiid II. H('rj,'('r. Hi'itrii<j:i' ztir Iveiintniss der Ijyniph-
eirculiitioii in dor Grosshinirinde. Airli. (. palli. Aiiiil. (cte.), Herl., 1898,
IM. ciii. s. r)',>r)-r)44.
■f liiiinuii y t'ajiil, S. Algiiims conjctums sohro ol inoeanisino anntomipo
do la idoaciiMi. asdciaeiuti y atoncion. Ui'v. do nicd. y cinig. pnid. Madrid,
18!),'). veil, xxxvi, |)|). 407-508. Trarislatod into (Joriiiaii in Aivli. f. Anat. ii.
IMiysidl.. Anal. Aldh.. Loiii/., Jahrij. 18!»r), Ii. 4/6, 8. ;{()7-;}T8. Cf. criticisin
by V. K(">llikor. A. I'olier die? none Iiy[)otliese von Uainon von dor Bodou-
liiiiiT dor Noiii-o,i,'lia-I''lonionto dos Goiiirns. Sitzungsbor. dor pliys.-niod.
tlosollscli. ■/.. Wiirzlxirg. 18!)(», No. 8.
X Hold. II. Hoitriigo znr Strnotur dor Xorvonzollon and iliro Fortsiitzc.
Dritto Abliandlnng. Arch. f. Anat. u. Physiol., Anat. Abth., Leipz., Sup ■
i)loinontband, 1897, S. 373-ol2.
:'!
\ i
Fl(i. TiH. — Pericellular networks l)elieve(l liy Held to he formed liy the tcvrniinals
of iixoiies. (ioliii i>rei>ar:itioiis tVoiu a eat tweiitv days old. Sections 7lt n.
thick. (.M'ter II. Meld, Arch. !'. .\nat. u. I'h.vsiol!. Keip/.. IS'lT, .\nat
Ahtii., Su|)i)l. lid., Taf. xiv, Ki>;s. 5, 7, and S. ) .\. Cell wilh lu'twork from
nucleus nervi cochlearis ventralis. The pi'ricellldar network surrouinls the
whole cell ;iim1 a dendrite i)assiut; upward. The tilire a corresponds to one
ol' the thickeued lil)res ol" the N. ci
descrihed liv Kaniou y ( a.ja
d
llidd. Mevoud the thickened spot lihrils jro to join theiicneral pericellular
iM'tworl
H. Part of the netwofk aroniul a cell in t
le nucleus uervi ves
ularis lateralis (l)eiters). Held helieves that the IhickeuiuKs in the net-
work ma.v ciM'respoud to the a^i^rejiatiousot' neurosouies whiidi stain in irou-
Ineuiatoxyliu i)re])a rat ions.
/, c, /. axones wlii(di help to I'orni tin
network. ('. Part of the netwin-k around a cell ol' the nuch'us inrvi coeli
learis ventnilis; the anastomoses of the eoiirscr suhdivisious of the fihres
n ami ft and the larger swuUings of the threads of the network are clearly
visiltle. ,._
vo
i ].
. {.
i
TFIK NKUVOUS SVSTKM.
3 !^
i t fl
"11
,' L
Slill
iihlc to show the t'oriiiiitioii by tcriiiiiial ii.xoiics of lu'ricclluhir
and iH'ridciidritic iii'tworks. This liiidiiijf is illu^Lriilcd in Ki;;.
;'(S. Tlic views of Apj'ithy us to the connection of many neu-
rones with one unotlier l>y means of ik urotihrilla' have also
l)een (h-alt witli in Chapter \'l.
As this l)0(jk is heiiif^ put throu<(li the press a novel idea
with re<(ard to intercellular substances luis been sugj^ested l)y
Nissl.* This investigator has throujfh the researches of liecker,
Apathy, and Bethe (cf. Chapter X III) recently been led to believe
that certain fibrillary structures demonstrable by special methods
within the protoplasm of the nerve cells are the elements actu-
ally cojicerned in nerve functions. On the (ground of as yet
rather niea<fre evidence he attempts to show that these fibrils
also exist indftidc of the nerve cells and their ))rocesses, in cer-
tai'i ])laces in <j;reat al)uiidance. It is his opinion that the es-
sential dilTerence between the j?ray matter and the white matter
of the central nervous system is not dependent, as those who
have worked with (Jolfjji's method contend, sim])ly ujx)!! the
enormous number of cell Ixxlies, dendrites, and collaterals in
the former and the immense number of medullated til)res in
the latter, but rather u[)()n the presence of a special morpho-
logical constituent. Siiuie there is much evidence that the
gray matter of vertebrates corresponds to the neurojjil of in-
vertelirates, and since in the latter Apathy asserts that he can
demonstrate as the })rincipal constituent a network of naked
neuro-fibrils (cf. Fig. 30, in Chapter \'I), Nissl thinks it likely
that the peculiar essential constituent of the gray nuitter of
vertebrates is a mass of these extracellular nerve fibrils in the
sense of AjKithy and Hethe. To this intercellular substance,
together with the neuro-tibrils in the protoplasm of the nerve
cells and their processes, he attributes the highest functions of
the nervous system. He grants that our techni(iue at present
is al)solutely insufficient to demonstrate the actual character of
the intercellular substances, but believes tliat he has brought
the proof that a specific constituent of the gray matter actu-
ally exists by a comparative study of the cerebral cortex of the
motor area in man (Fig. 50), dog (Fig. (!()), and mole (Fig. (il).
It is obvious from a v'omparison of these three figures that the
* Nis.sl, P. XorvonzoUcn iind firaue Siibstaiiz. Miiiich. mod. V,'c'lm-
schr., iJd. xlv, 181)8, .S. U88 ; 102;{ ; lOGO.
■^
THE KXTKKNAIi MOUIMIOLOOY <»F NKrUoNKS.
t)T
liifjIuT tlu> iiniiiiiil tho fewer cell bodies ii\ ureas of ^'riiy matter
of e(iual size. Now this discreijaiiey is attributed by Hainon y
Cajal and others to the easily demonstrable disproportionality
-,'i • .1-. « ', ,» •/ 1 J ... . ,•.♦,* .,
II.
4 III.
r^.:
r':?^:-
■-V,f
'(!;■;;.> .■■*<»W5i/.
■]
IV.
Fir., .'lit. U('i)np(liictiiiniil':i iili(pt<i>;i';mu>f'a pcriicndiculiir section tlimiiuli the tip
ol' tlic liciui of till' K.vi'i's rciitnilis iiiiliTinv lit' ;i licallliy adull iiiilil cliisc to
till' I'iilx. StiiiiiiiiK '>y Nissl's inctliod. I. Layer [ r in cells. II. liayeiof
l)yi'aini(ial cells, containing ".J - layer of small pyramidal cells i = ^. Mcy-
nert's layer) ) '.i — layer of laiKe pyramidal cells i — H. Meynert's layeri. III.
Layer of small cells . = -t. .Meynert's layer i. IV. Internal i(i> and exiernul
(51 /.one of the layer of mediiUated til)res i = .1. Meynert's layer". The re-
gion marked .") corresponds to the KaiiHlion-cell layer of Ilammarher;; and
the region marke(' <> to the spindle-cell layer. ^ .Vfter K. Nissl, Munch, med.
Wchnschr., Md. .iv, 1S))S. .S. I{l:i7. Via. ?,.\
of development of the dendrites and collaterals pertaininjj; to
the cerebral neurones of the dilt'erent animals, but Nissl denies
ftfi
TIIK NKItVol'S SYSTKM.
tlif !i(l(V|Hii('V <»f' tins ('xpliiiiiitioii. He asserts tlmt thiuiv of tlio
structures wliidi !i|t|)('iii' to l)e, !ili(l are (leseril)e(l as, deiidriles
of tlie pyraiiiitlal cells in (iol^'i prepuriilioiis euii not possildy
Fl(i (H». l{)<|)i-iMlii('(iiiii (pC a |)1i(iti)j;i"!iiii t'nuii a iit'i'iH'ndiciiliir cDrticiil section
thniiiKli til' siiimiiit nf iIk' k.vi'Us jii^l in I'nint iil' llic miIciis ciiiciiiliis nl' an
ailnU (IcpK cliisc to till' t'alx. Staining liy tiir nicllKHJ of Nissl. I roitirai
layer ''i-ee IVoni eells ; •^, siili<livisili|e into a nai rower external and a Itroader
internal /one. I>ut in noway lioniol<iKi<'al with II of l-'i^;. iW. On the other
liiinci, 2 in Viti. (iO eorresponds to H in V\}i. (il ; :? in Via- tiO eorresiioinls to I in
Via. '>1; 14151 = layer of mednllaled lihres eorri'spondinn to 5 ■ ti in V\<i. Titt.
and also to ,"> t ti in I'M;;, til. That is. t in \''\k. (M> eorresponds to 5 in Kin. til.
while ."> in Via. IMI - <l in I''iK- •>!• 1 After F. Nissl, Minudi. nied. Wchnsehr.,
Hd. xlv. isits, S. ltl^7, Kifi. 1. 1
1)0 dendrites tit till, iiiid maintains tliiit in any case in hiyer II
(Mcynert's '2. and :{. layers) of l''i<jf. 5!), there mnst be ti sub-
stance present wliich is entirely absent or at most ])resent in
bnt small amounts in the b()molof.jous biyer in V'v^. (!() tind Fifj.
()1. A diti'erence in the number of nerve-cell })rocesses, ^liii
cells, and glia fibres sufficient to account for the inequtdity in
the different specimens is, he believes, absolutely im})ossible.
This view of Nissl's is certainly most interestin<f, iiiul, com-
infX from so hijjrh a source, worthy of the most thouj^htful con-
sideration. Should it turn out that besides the nerve cells (or
fij'l
TIIK H\TKI{N.\L MoRI'lKM-Od V <)F NHl'KoXES.
}M>
iifiiriiiics) and the ;,'liii I'dls imd their liltrils tlicsc pcciiliar iiitcr-
cclliiliir stibHtiiiiccH do really exirtt, tho writor eont'esries that lie
would not he iiiiieh surprised. Nor is it iiiithiiikahle that ititer-
celliilar suhstaiiees in t he nervous system, if present, eoidd he ol"
tlie hi<;hest funelional iniportanee, for in other tissiu's \vi- have
not a little evidence that intercellular suhstanees play an impor-
tant role in physiolo<(ical proiicHses. Ono has only to retnend)er
tlu! Iluids of the hlood and the lihrils of the connective tissues,
for example of tendons, to satisfy himself in this rejrard. No
one, however, hesitates on t his account to hi'lievi' that hlood cells
ami eonneetivo tissue eidls exist, and that they arc of parain(Uint
importance; sinnlarly, even were interneuronal suhstanees of
great funutiuiuil signiticancu denionstrutud in the nervous sys-
I'lo. (11. -Tvcprodiictioii of 11 plmtDKniin of ii iiiTpciHliniliir section tliroiiKli tlio
fcrcl)i-.il cortex of a inolc 1 nini. in front of llic crnciiil snturc close to tiu'
falx. Staining; liy tile nietlioii of Nissl. 1 - exiernal layei' free from cells ;
2. cliaractcristic type of cell iirranKcinent in all cortical areas connecled with
llie otfactorins. especially in the loliiis pyriforniis ; :? i = )l ot' I'in. (io, except,
the thin cell-layer adjoinin;; the eell-fr<'e layer, wlii<'h reminds one still of a
of Ki},'. til 1 ; \ '=.i of KiLC. tit) > : ") i -- I of \'\k. lit) i ; ti i = 5 of Kin. till k i After
V. Nissl, Miinch. med. W( linschr., I5d. xlv, Isits, .s. 1(1^7, Kiu. 5. i
tetn, no one surely would draw the tibsurd conclusion that
nerve cells or neurones ilo not exist, or tluit they are of hut
little functioiuil value.
Brief reference only is necessary to the hypothesis of Rabl-
V
i '
ril
'{
ill
m
100
THE NERVOUS SYSTEM.
I
11 HI
iff
'W
Ri'u'khard * and the modifications and extensions of it by Dn-
val,f Tunzi, and otliers. J The whole doctrine by means of wliich
sleep, anivsthesia, the phenomena of hysteria, donble person-
ality, etc., are to be explained by amoeboid movements of the
dendrites, or the so-called " retraction theory," appears to be
based upon (1) the sinfjle o])servation of Wiedersheim with re-
gard to anueboid movements of the processes of nerve cells in
transparent animals like Lrjifothru Jii/((/iti(t and (2) the undu-
latory movements of the distal processes of the olfactory periph-
eral neurones. The idea has been severely criticised by von
KiUliker,** and it is worthy of note that a theory so feebly sup-
ported by facts has been so widely accepted and made the basis
of a mass of clinical generalizations.
* Uiibl-Iiiieklmrd. II. Siiul die Ganglienzellen nmohoid i' Einc Ilypo-
tliese zur ^Mechanik psychisclier N'orgiingc. Neurol, t'enlralbl., Leij)/.,, Hd.
ix (18U0), S. 199.
■f Duval, I\I. Hypotheses sur la physiologic des eentres iierveux ; t! eorie
histol()gi(jue du sonmieil. C'ouipt. rend. Soe. de biol.. Par., 1895, 10. s., il, pp.
74-77.
I Tanzi. I fatti e le iiiduzioui nelT odierna istologia del sistenia iiervuso.
Kivista speriin. di I'reniatria, vol. xix (18915).
* von Kolliker, A. Kritik dor Ilypolliesen von Rabl-Riickhard und
Duval iiber ann'iboidc He\V(<gungen der Neurodendren. Sitzungsber. der
phys.-med., Gesellseh., Wiirzburg (1895), 9. Miirz.
i 1
t
SECTION riT.
THE INTERNAL MORPHOLtHlY OF NEURONES.
chaptp:r X.
STUDIES BY METHODS WHiril UEVEAL THE INTERIOR OF
NEURONES.
Internal niorpliolojjy of neurones — Investigations of Ileniait. Max Schultze,
ami otliers — Dorli'ine of a tilirillary striiutiiri' — Sludics of Klciiuning
and Uogitil — Mctliod of Nissl — Stainal)le and un^lainable substances of
Nissl — Investigations of von Lenhosselv.
SuFFiciEXT lias been said to make apparent the extraor-
dinary significance of tlie methods of (iolgi and of Khrlich
for the investigation of the nerve structures. Certain it is,
that with regard to the external form of the neurones, the gen-
eral interrelations of these cells and their processes, tiie origin
of perijiheral nerve ti])res from cells in the nerve centres, and
the establishment of the existence of channels accessory to the
main conduction by means of collaterals, these methods have
led to clearer and more definite knowledge than any others
hitherto employed.
But a knowledge of the external form and connections of
nerve cells is by itself necessarily insufficient, and if we arc ever
to gain atiy adequate idea of the relation of the morphology of
nerve cells to their complex functions, the m-thods described
must be suiiplemented by others which (>nable us to penetrate
into the interior of the individual neurones, and to become ac-
quainted with the structure of the proto])Iasm of which they
are made up. Here we enter one of the most obscure domains
in the whole of histology. We stand before the cells and their
ultimate structure in the jiosition occuijied by histologists a
century ago as regards the individual organs and tissues. The
desirability of becoming conversant with the morphological Ha-
lations existing inside the nerve cells becomes all the more
lUl
II
102
THE NERVOUS SYSTEM,
;
i .iii
fill
'ill I
;
}
M'ti
M
obvious when one tliinks of the possil)ility of iiltiTnately being
able to trace u direct l)earin<jj of these upon function. Wlien
we remember not only the functions which the nerve cell pos-
sesses in common with all cells, but also the remarkable capacity
it exhibits for respondiiifi; to external irritation, and apparently
for recording and reproducing the happenings which go on
within it, processes which in groups of neurones we recognize
in what we call habit and memory, the significance of such a
possibility becomes evident.
Let us turn for a few moments to a consideratioji of the
studies which have already been made with the object of gain-
ing an insight into the internal structure of nerve cells. About
half a century ago, Remak * called attention to a fibrillary
structure inside the axis cylinder and cell body of certain of
the nerve cells; this was afterward further studied by Wolter
and Leydig in invertebrates, and by Heale, Frommann, Deiters,
Kolliker, and others in vertebrate tissues, but, it must be con-
fessed, with no very complete agreement among the various in-
vestigators.
The most notable of the earlier researches arc those of Max
Schultze.f This observer studied nerve cells and nerve fibres
from different parts of the central nervous system of different
animals, and has given us an elaborate description of his find-
ings, which, by the way, have done much to infiuence the
articles in the text-books ever since. The fibrillary nature of
the axis-cylinder process had been described before, but Max
Schultze asserted that portions of the whole cell body are
fibrillary, and further, that the fibrils are to be found within
all the processes of nerve cells and not simply in the axis
cylinder. The differences in appearance, he thought, depend
u])on the amount of iiiterfibrillar granular substance present.
This substance, he states, is scanty in the axis-cylinder pro-
cesses, while in ])ortions of the cell body and in the pro-
to]ilasmic processes it is often abundant. An idea of Max
Schnltze's conception can be gaiiuMi from a study of the illus-
tration of the larixe nerve cell from the brain of the tor-
pedo taken from his article (Fig. Vi'i). Schultze asserted that
*T{pnmk. R. NcMiroIoffisclip Erlilntprunjjen. Arch. f. Aiiat.. Physio',
u. wissonsoh. Mod.. Rprl.. 1844. S. 4(i!{-4T3.
+ Stricter. S. A Miiimal of Ilistoloj,'}', American transl. 8vo. New
York, 1872, pp. 1^4 d seq.
•■K''\>S
m
THE INTERNAL MORPHOLOGY OF NEURONES.
103
tlio fibrils which he described can easily be made out in fresh
cells prepared in serum without any staininj^ or lixinjf reaj^ent,
but that they are best demonstrated by bichromate solutions.
He further added that the nucleus lies imbedded in the finely
granular fibrillated material
central part of the
but does not ajjpear to
in any direct connec-
with the distinct til)rils
covering the exter-
nal surface. It was
also his idea that
the fibrils which
compose tlie axis
cylinder result
from the collection
into a group of the
fibrils from the ar-
borescent processes
of the cell ; that is
to say, tiiat the
fdjrils which are
seen traversing the
substance of the
ganglion cell do
[•iginate in the cell,
ly undergo a kind of
Mni'nt in it, and then
to the axis -cylinder
or extend into the
Fn.. fi2.-r,a„«lion ....11 fnmrtlHM.l.Ttri,. l.,i,.. "^her branched processes.*
oi'tli.. iiiiiiii iif th.. t.irpc.lii iis iiictiir.d iiy In vlew of what We know
Max S.'lniltz.'. <(. axis-cvliii.l.'r pr.iccss; j. ,, . , ,.
ft. i>r<.t<.i(iasuii.. pinc'sscs. Ji<)w ol the structurc of
nerve cells, and of what can
be made out with the methods he employed, it is almost incon-
ceivabh' how Max Sciiultze could have seen nerve cells as they
appear in his figures (Fig. (12). That his vicAV, however, is sur-
prisingly near that held as the result of some of the most recent
researches can not be denied. The study of the bibliography
l'«
,1 I
,1
I"
Op. cif., p. 1:57.
-SH
I(t4
Till-: NERVOUS SYSTEM.
I
ili
« ^
1
II
;il
since his time is rendered ditfieult by the faet that different
observers have used different terms to indicate the same thiiij^
— in fact, nowliere in Iiistoh)<jyi perhaps, has tliere been more
confusion than in dealing witli tlie granules and fibrils within
nerve (^ells.
The doctrine of the fi])rillary structure of the nerve cell was
supported strongly by Holl, Schwalbe, and lianvier. This view
soon nu't with o])ponents, however, anujng whom Arndt and
Key and Ketzius were, before Nissl's puljlications, the most im-
portant. The first, in 1S74,* describing the structure of the
s])inal ganglion cells, s])oke of the presence in them of different
kinds of " elenu'iitary spherules," which variri in size and in
general appearance. Key and Retzius f declared that the
ground sul)stance of the spinal ganglion cell was homogeneous,
but that Ml it numerous strongly refractive round or oval granules
were 2)rcsent ; and they thought that the appearance of a con-
centric triation or fibrillation could be simulated through the
arrangement of these granules in rows. Flemming, in 1882,J
saw granules within the cells which would stain with nuclear
dyes, azo dyes, and luvnuitoxylin, but nevertheless affirmed a
filjrillary structure of the central cells, and of a tortuous or
much-curved threadwork within the spiiuil ganglion cells be-
tween the granules. He did not believe, however, that in the
spiiuil ganglion cells there were long connected fibrils, such as
the earlier ob.-ervers had described, but thought that the cell
body was in the main constituted of numerous, evenly dis-
tributed, very short threads, which showed sonu'times finer or
coarser thickenings upon them, observations which were sup-
ported subsequently by E. Midler.* Flemming has recently
* Ariult. H. riitorsiicluiiijjcii iilicr die (iiinf;lii'tik<")r|ii>r des Ncrvus syni-
pathicus. Art'li. f. iiiikr. Anat., Hoiin, IJd. x, 1HT4, S. 208-241.
f Key. E. A. 11. and (J. Hetzius. Studieii inder Anutoiiiie des Nervensys-
toiiis imd (It's Miiidcj^ewclx's. 4to. Stockliolni. ISTfi.
if Flemiiiinfi;. W. Meitriip- ztir Aiiut. ti. Einl)ry()i. ais Festfjalic fiir .1.
Ileide. 1HH2. Roiin. S. 13. In this article the previous bibiiofjfraphy is
thoroiiirldy rcvic'wcd. ("f. also, Teln'r den Ran dcr Spinalf^-atifjiicnzcllen bei
Siiufjetiiieren. und Hcnierkinifjen iilicr den der ci'nl ralen Zellen. Arcii. f. inikr.
Anat.. Bonn, IHitf), Md. xlvi,.S. ;{T!»-;5i)4. and Die Struclurder Spinalj,nuij,dien-
zelieii liei Siiiip'tieren. Arch. f. Psyehiat. u. Nervenkr., Mcrl., lid. xxix (IH!>7),
II. :J. S. !»6iM)74.
* Miiller. Erik. Untersuchunfjen iiber <len Man der Spinalgaiiglieii.
Nord. Me<l. Ark., Sloekholni, 1891, n. R, i, 1-55.
i
Till-: IXTKKNAL MOUPIlOLOUY OF NEURONES.
105
published two otlicr articles* in whieli he warmly supports the
doctrine that fil)rils exist inside the nerve-eell protoplasm. In
Fig. t;;}, taken from one of these, the tibrils are pictured.
Kronthal and Doj^iel have
also expressed themselves in
favor of the view of a tihril-
h
le
hee
lively
vie
(
von
bur
vigorous opponents. In that
year Nissl published the
first of a series of articles f
in which he laid stress u2)on
the appearances to be made
out i?! tissues hardened in
alcohol and stained in basic
anilines, such as magenta
red and methylene blue.
Although the structures
described by Xissl had been
observed earlier by Flem-
ming and by Henda, it was
through the introduction
of Xissl's methods, which
bring them especially well
into view, that their arrangement in the protoplasm and their
significance for the function of the cell could first be studied.
* Flc'inmiiig, W. Uebor die Stniktiir centraler Nervcnzcllon bei Wir-
b('lti(Meii. Aiiat. Ileftc, I. Abth., 10. Heft (Hd. vi, II. 3).
f Tlie priiieipal contributions of Fninz Nissl foncennng the structure of
nerve ceils lire the foliowiuf,': Ueber die Untersuchungsmetlioden der (Jross-
liirnrinde. Taf,'ebl. d. W. Versainnd. deutsch. Naturf. u. Aerzte in Strassl)urf^
(1885), S. r»0(». — Teberden Zwsaninienhanjf von Zellstructur und Zcllfunclion
in der centralen Nervenzelle. Taipei)!, d. (!!. Versaininl. deutscii. Naturf. u.
Aerzte in KOln (1888). — Die Kerne des Thalamus beiiu Kaninchen. Tajjcbl.
der 62. Versaminl. deutsch. Naturf. u. Aerzte in Heidelberg (1889). — Ueber
Wm.^^ ■
Fio. (>3. — Xerve cell from the re};i<>n of tho'
ventral ('(ilumn of firiiy matter of tlie
spiuiil conl of (iiidiis. Suliliiiialc tixatinn ;
luematoxylin staining. (After Flcin-
niinn- ) I'hc axonc is seen cniiiinn oil' from
tlu' lower end of the cell. In the axoue
and at its orinin in the cell body a liliril-
lary apiK arance is seen. In the interior
of the cell liody the spindle-shiiiied granu-
lar masses are deeply stained, while lie-
tween tlieni are Klennniufi's filirils, cut
generally ohiiciuely <ir transversely.
iv
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1
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1U(5
THE NERVOUS SYSTEM.
I I
i I :, '
Nissl's early niethods consisted of ,stainiii<? tissues hardened in
alcoiiol witli Maj^eiitu I'ed or nietliyicno blue and elearinj,' in t)il ot
orifi^anuin. The method has undergone several niodilieations. the
most recent of which will he {ifiven hcu-e. inasnuich as it does not
seem to be so jjfenerully known as it should be. In an article* pub-
lished in IWM Nissl describes it as follows: Small blocks of tissue
are hardened in ninetj'-six per cent alcohol and fastened by Wei-
gert's mtithod with yum arabic without iinbeddin<^. The sections
are received in ninety-six per cent alcohol and stained in a watch
{flass. The stain is to be heated over the s])irit flame until small
bubbles arise which make a cracklin<»' noise H'>i}° — 70° C) ; sections
are then transferred to aniline-oil alcohol until dilferentiated. The
process of differentiation is ended when no more coarse clouds of
color <^o off into tlu' fluid. The section is then transferred to the
slide, dried with filter i)aper, after which some drojjs of oil of caje-
(lie X'crJinderungen der Nervenzollcii luii Faeialiskerii des Kaninciicns nacli
Ausrc'issiiiig des Xcrvun. Allg. Zt,s('l)r. f. Psycliiat., etc., Herl., IM. xlviii
{18yf-"!)'2), S. 197. — I'oljercxpcriinciiti'll crzcugtc W'raiRlcniiigcn an der. Vor-
derlioriizelloii des liiiekeninai'kes be! Kaiiinelieii mil Deiiioiistralion iiiikro-
.skopiseher I'Wiparate. Allg. Ztselir. f. Psyeiiiat., etc., Herl., Hd. xlviii (1891-
'!>-), S. 07r)-6S'2. — ;\Iittlieilungeii ziir Anatoniio der Nerveiizelleii. Allg.
Ztsclir. f. Psyehiiit., etc.. Herl.. Hd. I (IHiW).— Ueber Hosiii's iieiie Fiirbe-
nietfiode de.s gesiiimiileii Xerveiisy.steiiis luid desseii iSeiiierkuiigeii iiber
Ganglienzellen. Neurol. C'eiitrall)!., fjeipz., Hd. xiii (1H94), S. 98 ; 141.— I'eber
eine neue Untersueliungsiiietiiducdes Centralorgausspeeiell zur Feststelluiig
der Localisation der Nerveiizellen. Ceiitralbl. f. Nervenh. ii. I'syehiat., <'()-
bleiiz 11. Leipz., ii. F., Ud. v (1894), S. ;5;i7-;344 ; also in Arch. f. Psyehiut.. Ik-rl..
1894, Bd. xxvi, S. 097-013. — Ueber die sogenannten Granula der Nervenzel-
len. Neurol. Ceiitralid.. Leipz., Hd. xiii(1894),S. (170; 781; 810.— Mittlieilungen
uber Karyokiiiese ini eentralen Xervensysteni. Allg. Ztselir. f. Psvcliiat.,
•etc., Herl., Bd. Ii, 1894, S. 245.— Bernlianl von Gudden's liinianatomiscbe
Experinientaiuntersuchuiigen. Allg. Ztsehr. f. Psycliiat., etc., Berl., Bd. Ii.
1894, S. 027-049.— Der gegenwiirtige Stand der Nerveiizellen-Anatoniie
und Pathologie. Centralbl. f. Nervenh. u. Psycliiat.. ('ol)len/i u. Leipz., n.
F., Bd. vi (189o), S. 1-21.— Feber die Nonienklatur in der Nervenzellen-
anatornio und Hire niiehsten Ziele. Neurol, ('entrall)l., Leipz., TJd. xiv (lS9r<),
S. (!' 104.— .Mittheiluiigen zur pathologisehen Anatoinieder Dementia jiara-
lytiea. Arch. f. Psycliiat.. Berl., Bd., xxviii, 1890, S. 987-992.— Ueber die
Veriinderungen der Nervenzollen naeh ex[ienmentell erzeugler Vergiftung.
Neurol. Centralbl., r^eipz., Bd. xv (1890), S. 9.— Ueber die ortliclien Bauver-
sehiedeiiheiten der Hirnrinde. Arch. f. Psycliiat., Berl.. Bd. xxix. 1897. S.
102o-1027. — Die llypothese der speeifischen Nervenzellenfunction. Allg.
Ztsehr. f. Psycliiat., etc., Berl.. Bd. iiv (1897), S. 1-107.— Ueber Nervenzellen
und grauo Substanz. Miinehen. ined. Wchnselir.. Bd. xlv, 1898, S. 988, 1023,
1060.
* Centralbl. f. Nervenh. und Psycliiat., 1894.
-.Jft aJg A-
THE INTERNAL MOIIPIIOLOGY OF XEUUONES.
101
put are applied and the sections are again blotted witli filter pa)K'r.
A few drops of benzine ar»^ i)oured on, then some benzine-colopho-
niuni. and the slide is heated until all the Ix-nzine jius lias Ixsen
driven oil".
The dye is made as follows : Methylene bhic B. pat., .'{.75 ; Vene-
tian soaj), 1.7*); distilled water or soft water, l,(Mt(t. Tbc diU'ercn-
liatin<f lliiid has the followinjif eoinj)osition : Ten parts of colorless
aniline oil and ninety parts of ninety-.six per eent alcohol. Nissl
obtains his aniline oil directly from the factory at Hochst, and
keejjs it carefully ])rotected from the lij^ht.
The ben/ine-colophonium is prei)ared by pouring benzine n])on
colophoniuin (white rosin) and allowing it to stand for from
twenty-four to thirty liours. The llnid. transparent mass which
results is ready for us<> ; the desired thickness can be obtained
either by the iiddition of benzine or by allowing it to evaporate.
In mounting, while driving olF the l)enzine gas. the material may
catch lire, but if the llame be blown out iininediately, no injury is
done, and the alterations produced by burning are <iuite character-
istic and easily recognizable.
Tlie iiu'tliod of >i'issl perniits in some respects of a very ex-
act morphological analysis of the bodies and nuclei of the cells.
His method of elective staining distinguishes witliiu the cell
bodies always two, sometimes three, constituents which are
sharply separable from one another and easily recognizable.
One of these ccmstituents of the protoplasm stains intensely
blue by his method, and is spoken of by >»'issl as tlie stainable
or visible formed part of the nerve cell.* The second con-
stituent remains entirely ujistained and is spoken of by him as
the imstaiiiable — that is, the visible unformed part of the nerve-
cell body. In addition to these two constituents, in many nerve
cells the well-known pigmentary deposits are visible.f Leaving
* Nissl says: " Bruclistiicke tics fiirbbarcii, id <'.s/, des sichtbar gcforniton
Thi'ilos (les Nervenzclloiikru-pors." Neurol. Centralb.. Lcipz., Ikl. xiii (lHf)4),
.S. 07(1.
\ Tilt' .siil)staiices wliicii stain black with osniic acid in many nerve cells,
well known to all who have employed the method of ]\Iarclii in the stiuly of
Iminan nerve centres, have reeently been made the oljjeet of especial re-
search by Rosin. Cf. Rosin. II. I'iin Reitrag zur Lehre vom Ran der
Gaiifjlienzellen. Deutsche mod. Wchnschr.. Leipz. \\. Herl., Rd. xxii, 1H!)0,
S. 40.')-4))7. Similar structures are abundant in the gan.uflion cells of the
monkey, as 1 can assert from specinu'us shown to me by Dr. Melius.
Tills jiif^ment appears its litrht yellowisii masses in the large motor cells of
the ventral htirns of the spinal vnn\ and in the motor nuclei of the me-
jl
' ''%
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m.
108
TIIK NKllVors SYSTKM.
tlic ])ifi:nuMit for tlio tiino }»i>iiijr (tut of t'oii8idoration,mii('li is to
he k'iinuMl from ii study (»f tlu' cliiiructer.s of tlic staiiuibk' portion
iiutl its ri'liition to tlii' iion-stiiiriiibU' portion of tlu' cell body in
ditferent cells in various parts of the central nervous system,
and upon such studies Nissl has built up an elaborate classifica-
tion of nerve cells. This will l)e referred to in the next chap-
ter. Any one who takes the trouble to use Nissl's method in
the way that he has directed can easily convince himself of the
relial)ility of his descriptions. The stainable portions in tlie
nerve cells show a series of ditferent forms ; smaller and lar<:jer
granules of regular or irregular shaj)e, groups of granules, and
rows of granules can be made out. Often the stainable nuisses
are arranged in threads, sometimes smooth, sometimes rough,
and varying in thickness, course, and length. Often larger
structures, regularly or irregularly shaped, arc to be seen, Avhich
stain with varying degrees of intensity. Some of them appear
homogeneous ; others show an internal constitution, complex
and difficult to describe. Of the larger bodies, tliree varieties
are especially iu>teworthy :
(I) The so-called nuclear caps {Kvnikappen)^ stainable
masses which possess the form of regular, sometimes of irregu-
lar cones, each hollowed out internally like a cap, correspond-
ing to one pole of the nucleus \\\)o\\ wliich it sits. There may
be two of these nuclear caps within one cell body, correspond-
(hilla ; ill tlie j»yraiiii(liil cells of Betz in the cerebral cortex: in the colls of
the nucleus dorsalis and in other parts of the central nervous system. Curi-
ously enouf^h. when the pij^inent is present in nuvsses in the nerve cell tlie
tigroid aijgi'ejjations appear to beaiisent from a portion of the protoplasm in
which the pigment is situated. The jiigment here described is not identical
with that of the locus co'i-uleus. the substantia nigra, ti.e substantia ferruginea^
etc. The relation of the substance or substances here concerned to what we
have been accustomed to look upon as pigmentary deposits should be fur-
ther investigated. Uosin believes that the pigmentary substance is allied
to fat. It not o stains black with osmic acid, but if the tissue be previ-
ously treated witli alcohol and ether the osmic reaction, it is said, is not
ol)tainabie. Acetic acid has no effect upon the reaction. According to I'ilcz,
Obersteiner, and otliers, Hie light yellow pigment appears at different peri-
ods of life in different n, e cells; thus in the cells of the spinal ganglia it
is first found at the sixth year, while in the spinal cord it appears first at the
eighth year of life. As age advances the amount of pigment in the nerve
cells gradually increases, a fact entirely consonant with the idea that the
l)igment is a result of catabolic metabolism. Van (Heson refers to the pig-
ment as " metaplasm granules."
m
1
if fc/i
THE INTEUNAL MOIilMIOLOU V OE XErUONES.
lot)
ing to two opposite iiuolcar poles, and oeeasioiuilly, aceonliiijr
to Ni.ssl, cells are seen in whicli three sueii caps are i)reseiit.
(;5) So-called wedf^es of division ( \'frznri(/i(ii(/K^-('!/rlii),ntii\n-
able nnisses which fill completely the an<,'le at the point of divi-
sion of u nerve-cell process.
{'.]) Spindles, oblonjf or s))indle-shai)e(l stainahle masses which
are thick in the middle and l)ecome thinner toward the end,
occasionally rnnniiig out into threadlike forms. One-sided and
double-sided spindles exist.
Any one of these forms may be vacuolated, as has been
pointed out by Nissl, von Ijcnhossek, Held, and others.
Von Lenhessek, who has also stronijly opposed the idea of a
fibrillary structure for nerve cells, has in the second edition of
his book * given us a very accurate description of the appear-
Yui. M. — Lai-fii" motor KaiiKliim cell from the ventral liorii of the spinal cord of
the ox. Tliionin staining. (After von l.enlios.sek.)
nnces within the cells of the ventral horn and the cells of the
spinal ganglia. Ventral horn cells, examined fresh or in an in-
different Huid, show little if any structure. The proto])lasm is
yeen as a smooth, glistening, indistinctly granular substance in
* von LenliDssi'k, M. l)er feiiicrc l?aii des Xervensysteins im Lichte
neuestcr Forschungeii, 2te AuH., Berlin, 1895.
I'
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i
10
TIIK NERVOUS SYSTEM.
l!)
1 ;! I
:
wliicli soinctinios n sli<;Iit concentric iirraufrcJiiont iiii<l, in the
rc^'ion <»!' tiu' pi'dccsscs, an indistinct l()n<,'itn<linal st rial ion can
1)0 luudo out. Tlio ycllowiali granular pijjniont is very evident
ill tlio fresh (U'lls. As a staininj,' method, von Leidiossek has
found lliat thionin (Fijr. (U) yields results as good as, if not better
than, those obtained with methylene blue, and my own experi-
ments with this dye have been ecjually satisfactory, though in
my experience crystalline deposits have been more frequent in
pre])arations stained with thionin than in those stained with
methylene blue. \'on Lenhossck very properly objects to the
tertn "granules " for the stainable substance, the nuisses ordi-
narily referred to being much too coarse to be so designated. He
has pointed out, further, the differences in ai)pea ranee dependent
upon thickness of section and upon whether the nu'dian or tan-
gential l)e the mode of sectioning employed. He has described
theditfi'rences in size and concentration of the stainable nuisses in
different animal species, and states that the clironu)phile masses
are especially coarse, both relatively and absolutely, in the ven-
tral-horn cells of the rabbit. He has laid stress upon the dif-
ferences in ai)pearance in the different parts of the cell ; thus,
the arrangement in the centre is often quite different from that
visible at the periphery of the cell body, ami the stainable
nuisses in the dendrites again show different characters. He
has further pointed out differences in interiuil character be-
tween the ty{)ically stellate-shaped cells of the ventral horns and
the oval elements which are met with there, and attributes the
differences in shape of the " chromophile corpuscles," as he
calls the masses of stainable substance,* to developmental rela-
* The .stuiiiable substance of Xissl has recently been designated " tigroid "
(from the Greek woi'd TtypoeiSiis. sjiotted) l)y von Lenliossek, in an article
entitled Ueher Nerven/.ellcnslrucluren. Verhandl. d. anat. (Jescllscli., ,Tena,
1800, Hd. X, S. 15-21. Van Gieson in his publications refers to it as the
"coliageiious siiijstance." In his article in tlic Miinchenor medicinisclic
Woehenselu'ift of August, 1H!»S, Xissl urges that a whole series of ditTerent
substances which behave difTerently both niorplu)logically and tinctorially
in the "ecjuivak'nt picture "are represented by wiuit he calls the "stainable
substance." lie thiid<s it very wrong tluit these siiould lie thrown all to-
gether and designated either '* Nissl's substance "or "tigroid sulistance."
He is willing, however, that the stainable substance of the motor nerve cells
be called "Nisslsubstanz," and that that of the spinal ganglion cells be re-
ferred to as " Tigroidkorper." I'ntil. however, we know more about the
substances in the neurones which stain blue by the method of Nissl we need
trouble oiu'selves but little with regard to such refinements of terminology.
i (■
TIIK IXTHIJNAIi M(>I{IMI()I,()(iV OF NKrUoXHS.
II
tions. Do Qucrvain * has sufrfjosted that all tlic chromopliilc
bodies n'])ro8ont iniiltiitlcs of line /ininiilcs, and von Leidiosst'k
admits that tho bodies are rarely liiii'ted by a sharp line, imt
that they, as a rule, show irregular, ()rten jagg*'d, uuirgins, and
often look jit their borders as though they were broken up into
small granules. Ho refuses to admit, however, that all such
bodies represent aggregations of minute granules, a j)oint al)out
wiiich more will be said when the work of Held is discussed.
\'on Leidu)ssck has studied with care the relations of the Nissl
bodies in tho dcndritos, and finds that from always being few in
nund)er thoy cease to appear at a certain distance from tiie cell
body, and as soon as the dendrite has reached a certain thin-
ness. Jn tho deiulrites, their shape and general appearance are
quite different from those of tho interior of tho cell body ; they
form long, narrow, straight, rod-shaped masses, often sharpened
distinctly at the ends, so as to form definite spindles the long
axes of which are ])arallel to that of the process. The vari-
cosities on the dendrites in (Jolgi preparations von Lenhossi'k
holds to be due to superficial collections of chromophile sub-
stance. f His description of the origin of the axone is particu-
larly clear and accurate.
Schatt'er J was the first to descriljo tho peculiar behavior of
the axono and the adjacent portion of tho cell body as regards
Xissl's staining. The axone itself, unlike the dendrites, is en-
tirely free from the stainable substance of Nissl, as is also the
portion of the cell body immediately adjacent, known as the
axone hillock. This hillock is nuirked oil' by a tolerably sharp
curved plane from the granular pr()toj)lasm of the cell body,
and shows at its margin not infrequently a layer of especially
fine granules. With Kronthal's method, the axone and axono
hillock stain intensely in methylene blue, very much as in the
vital staining of Khrlich. Hat Honda found that when specimens
thus prepared were cleared in (Toosote the axone and axone hill-
* De Qiiervnin. Frit'.. Uober die Vcriliulerunjren des C'entnilnervensys-
tems bei experinientolier Ivachcxia thyreoprivii der Tliiere. Arch. f. jiatli.
Anat., etc., Hcrl.. I?d. cxxxiii (18i);5), S. 481.
•f Tlie writer has froqui'iitly ol)tiervc<l varicosities in the course of the
dendrites in pathological tissues, and in these there appears always to be an
accunuilation of the tigroid masses.
X SehafTer, K. Kurzc Annieri<ung iiher <lie inorphologische Differeiiz
des Axencylinders iin Vcrhilltnisse zu den protoplasniatischen Fortsiitzen
bei Nissl's Fiirbung. Neurol. Centralbl., Leipz., Bd. xii, 1893, S. 849-851.
i
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112
TIIK NKliVors SYSTKM.
<»('k lost their color, iiiKJ only tlic stiiiiiablc Hiihstiiiico of Nissl
retained the dye in the cell hody and the dendritis. Henda *
iniikes one exception to this statement. In the basal axones of
the pyniniidal cells of the cerehriini, especially of those known
us the j^'iant pyramidal cells of Hetz, the collaterals which come
olT at ri;,'ht an^^lcs are visihle when the preparations are stained
hy Henda's inethylene-hluo method. .lust at the hejjiinninfj of
the collateral, a small wedf;e-shape(l fjranule, in section trian{,'u-
lar, takes up the methylene blue, the axone itself remaininj^
(juite unstaiuahlc. 1 have nu't with this observation nowhero
else ill the bibliof^raphy.
\'oii Lenhossek has not been able to make out definite fibrils
in the cell hody, and one gains the impression that he disbe-
lieves in their existence. He has taken the trouble to stain the
cells of the brain of the torpedo, the oliject of .Mj.x Schultze\s
classical description, by Missl's method, and denies the existence
of fibrils in them.
In his study of the s])inal ganglion cells, von Ijenhossek
used specimens from the ox (Fig. (ia) as well as human tissues.
In the fresh cells, teased without the ac-
tion of reagents under high powers, he
could make out a distinct, finely granular
consistence, the granules lieing closely and
evenly arranged throughout the whole
cell. He could not decide, however, from
the fresh tissue whether he had to deal
with actual granules or with the optic
a])]iearaiices of threads. In Nissl jirejia-
rations, however, and in specimens stained
in thioiiin the cell ap])eared nearly always
to consist of two distinct layers — an inter-
nal ])eriiiuclear layer, which stained deep-
ly in the basic dye, and a peri])lieral layer
of lighter color, the two layers passing
graduali , ^'r into one another, although occasionally a sharp
separation between the dark endojilasmatic and a lighter ecto-
plasmatic zone could be made out. Von Lenhossek could not
find in the ox the concentric arrangement of the granules de-
-I'lr-l'-fv. '
0^::iy
'^ih
m
■J,
Fio. <i.i. — Siiiiial KtiiiKlioi)
ctll IVdiii the ox liciw-
iii^' clciii- spaces ( '
iilvii"). MaK"'!'
iiifl. (After
liossek. )
* I5('ii(la, ('. Ut'luT (lie nedeutuiif; dcr (lurch l)asisclu' Aiiiliiit'arlieii
ilarstellliaren Nerveii/ellstruclureii. Neurol, (Viitralbl., Loipz.. Hit. xiv. 1H'J5,
.S. 759-TG8.
TIIK INTKItNAI. MOltlMlOliOdY ol' N'KntON'KS.
i:^
scribed hy Nissl in liiuiiiiii spinal ;^'tiii<;lioii cells, at least in llu;
majority of cells, lie noticed the uneven si/e of tlie stainable
masses and their arran;,'enicnt into a lu't worklike a|i|tcarance, as
dcscril)"d liy other authors, in sonu' cells of the spinal <;an;,dia
von licnliossek fouinl, in accordance wit h l''lcniniin;^''s ohscrvii-
tions, <jranules which are much coarser than those ordinarily
seen in such cells, hut he does not think a classitication into
coarsely jiranidar and liindy ^'rannlar cells is desirahle, inasniiich
lis both kinds lie everywhere inlerinin^dcd and there appears to
1)0 no local connection between the estent of the cell and tho
size of its <jrannles. (ienerally s])eakin<:, the coarser jrrannlation
is seen in tln' smaller cells, the lar<i:e cells bavin;; always a finely
^n'anular stnn'tnrc, appcaraiii-cs which contrast stron^dy with
those nu't with in the cells of the ventral horn. \'on Lenhossck
describes at some length wluit every onv who has studied the
spinal ^an^lia must be ac(|uainted with — nanudy, the pres-
ence of (dear areas in the jjrotoplasni of some of the cells.
These areas are to be fonnd, as a rule, in the peripheral portion
of the c(dl, sonu'times as many as three or four bein;,' present in
a single (rcll. 'I'hcy an> spherical or eili))tical in shape, often
larger than the nucleus, and do not represent striuitureless
Fiii. (iti.— Spinal Kaiijjiioii cell of Hiiiki ('iitfslninin. ( \ftvr Hulicr. ) A siilc til>ril,
II, is to Ih' sci'ii (liviiliii<; into tlin'c Itraiiclics, carli of wiiicli tcnniiiatcs in an
fiid disc ; tlif ricar /.oni' of |)i'oto|)lasni, /*, Ix'nratli two of tin- discs is shown
spiices tilled only with Ihiid, but contain nortiial ground sub-
stance, and besides often show in their interior a few gnmules
widely separated from one another. The exact natnre of these
9
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■:'i^
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11 +
THE NKIIVOUS SYSTEM.
Viicuolc-Iiko s|)()ts is us yet not (^Iciir. It is not iiiipossiblo tliat
sonic of t hem correspond tollic position of Icrniiifiil end discs
of side librils coming olT from the ji.\(»nc and ninninjj; IkicIv to
the cell body, such us hiivc^ been (h'scribed by ilubcr, of Ann
Arbor,* in the spinal ;,'an^lion cells of the froj;; ('*''K' *"•")• "t*
states that there is usually foniul a clear zone of protoplasm
surrounding the expjinded end of tiie ])ro(!e8se8.
* llulicr. (i. ("ml. The Spiniil (iaiigliii of Ainiiliihia. Anal. An/,., Jena,
l?<l. xii, IHIMI, N(.. IH. S. Iir-I'jr).
■
("IIAITKR XI.
VAKIKTIKS OF NKItVK CKI.LS IMSTI N(U' IHII A HLK MY NISSl/s
MK'I'IIOI).
(Mussificiitions of iKMinuics luiscd ii|iiiii N'i^sl's stainiiifj iiiftliod — Smimto-
chroinn, cvlocliromc, and caryocdinum! msrvi- cells — Arkj(iclir(irni%
sticli()clir()iii(\ arkyusticliKclinimc, ami fjryofhniinc nervu colls — Objee-
lidiis Id Nissl's c'lassiliciitioii — l'vcn(piii()r|ili(iiis. iipyi'iioinoriilioiis, and
parapyi.'iioiiKirplioiis ('ondil ions — ( 'hroino|iliili> crlls.
Nissi, lias spent several y<'ii'"« in f'i<' niost, exact investi-
jjatioiis of the nerve cells in the diirerent parls of th(f nerve
centres of man and aiiiinals, and has conn! to the eonclnsion
that definite types or varieties of nerve cells exist, varieties
which are constant not oidy in tiie same animal, hut often exist
characteristically in hoinolo<^oiis localities in a whole series of
animals. li(> has had some ditliculty in finding suitahle desig-
nations for these types of nerve eells. In the present st'iU; of
our knowledffe, a. nomenclature l)ase(l upon function, except,
perhaps, for a few cell cateojories, is not just ifiahle, and N'issl
has been compelled to classify th(! cells accordinjf to their mor-
pliolof,ncal characteristi(!8. According to him, all the cells in
the nerve centres, excu'pt the so-called vhrdiiiopliiU' nerve cells,
can he divided into two main classes.
'Pile first group includes the nerve cells which possess a
well-marked cell body which surroumls the nucleus completely
on all sides, the TjrotoMlasm having a distinct contour. These
cells Nissl (uiUs xomninrlironh' nerve cells.
To the second group (subdivided itito two groups — cyto-
chrome and caryochrome) Itelong those cells in which in Nissl
preparations tiie nucleus is most in evidemu' ; the nucleus has
a clear contour, but only indications, as it were, of the cell body
are present, an apjiearaiice due either to scanty d((velopment of
the cell body or to the predominance in it of the unstainable
substance. These (;('ls often look as if they were naked nucUu,
though by ("olgi's method it can be shown that they may p(»s-
sess definite axones and demlrites. In some of these ciells the
115
:
'hi
■ If ^i
110
TIIH NHRVOl'S SYSTHM.
r I
II
i H
st:iiiml)lp substance may l)c present, tliougli wlien it is, it is very
unevenly distributed, heini,' eollec^ted ut definite points in tin;
eell, the nucleus apparently heinjif only partly surrouiuled by
protoplasm. Such cells are to be seen in the substantia f^ela-
tiiiosa of Rolando, ^s'issl su^j^ests that the nerve cells with an
ill-developed cell body, in which the nucleus ap]iears to be in-
eonipletely surrounded and does not exceed in size the nucleus
of a i;euro>;lia cell or of an ordinary leucocyte, be called "y/v^//-
tih's " ( Ki'iniir) or fiihirhrdiiir nerve cells. These cells are present
in great numbers in the granular hiyer of the ci'rebellum. There
are dill'erent varieties of these cytochrome cells, those in the
//
/
//
III
w
\
v ■ I
i
I''l(;. (17. — Nt Tvc cell iVdiii (illii(li)i> liiillxiC liililiit. ( Al'tcr Nissl. ) SoiiiMliiclinpiii.-
Ill TVc cell (pf llic Mrkydcliiiiiiic Viiiicly in llii' piiiaiiyUnoiiiiiipliims iniKlitinii.
'
■ere])ral cortex, those in the cerebellar cortex, and those in the
olfactory bulb, for example, being l)y no nutans i(lenti<'al.
Tlu' secoiul subgroup of cells in which the cell l)ody is only
indicated, but in which the staiiu'd nucleus is of the size of
that of an ordinary nerve cell, or al any rate is larger than that
TIIH INTKHNAIi MoHI'HOI.OOY OF NErROXKS. 117
of ii lU'Ui'oj^liii ('I'll, Nissl calls ctiri/dc/inniir iiiTvi' cells. (M'
these there are also distinct varieties — for example, those of
the substtintia gelatinosa of the spinal cord, and those of the
y^^
X
V\^^<. fiK. — Nerve cell fnim (Icivsnl nileleiis of iiroxiliiiil iKivtinii cif iiiediillii of nihhit.
(Afler Ni>sl. ) Siiiiiiiluilirniiie liervi> cell of enMlkyncliiiiiiie iype ill iipykiio
iikh'IiIkiiis ('(intliliiiii.
<ran<fIion habi'iiula' — types which for the present are designated
simply by letters of the (ireek alpliabet.
The majority of the nerve ct'lls, however, fall in the lirst
group — that of tiie xdiiiatoclirdiiit' (lells — where the cell body, if
we judge solely from its morphology, has a])parcntly far greater
relative im})ortance than the nucleus. Hut this group contains
a series of ty])es of nerve cells which are distinguishable from
one another in part through ditferences in the nuclei, ])ut
mainly tlir<»ugh dill'erent relations of the stainable and un-
slaiuable constituents of the cell l)ody. Nissl divides the so-
nuitochrome cells into four great groups: tlu' (ir/i\//(ir/irniiH', the
nfirhor/rniiiH'^ the (ir^'i/osfir/tor/iroitic, ami the (/ri/or/trnDH' nerve
cells. Ill the arkyoohrome nerve cells the stainable portion of
the cell body appears in \issl pri'parations in the form of a
network {apKv^). The branches of this network ai)pear to be
distimstly connected, but Nissl notes that in many of the cells
in this group there can be made out processes into which the
distinct network of the perinmdear part of the cell body can go
3
ft I
-'i
I ''ill!
!Ul
118
TIIK NKKVOUS SYSTEM.
over, so as to form a jjarallol-stripcd arranfifomoiit. As a sam
plo of cells holoiij^inj^ to this j;roiip, Nissl pictures an arkyo-
clirome olfactory cell (Kifif. 07). Among tlie arkyochronie nerve
cells, Nissl further distinjjuishes ennrki/or/iroiiie forms from
mupliitrk-iiorlironir forms. Tiie former show the stained (M)Ii-
stituent arranged in the form of a network which dilfers from
Flo. (lit. — Motiir iiiTvc cf'll riuiii vent rill Ikhii nfKniy mat (it (iCspiiinl cunl of rab-
bit. (.M'tcr Nissl.) Of till' tlircc liiwcr iiniccsscs, tbc middle (Hic i-i'prcsciits
llic aXdiU'. .MI tlif otbci- proccssfs arc dendrites. Tlie marjjiiis of the eidls
and of the masses of staiiiahle sulistaiiec appear too sharp in the reproduc-
tion. At the allele of the division of the lar^e dendrite at the left superior
anKh' of the cell is shown one of the " wedfres ot division" ( \'fi-:iifii!ini(}x-
kcili'hi). The spindle-shaped Nissl bodies ar<' well shown, espeeially in tho
dendrites. Thiseell is classed by Nissl a^ a stichochiome nei've C4dl in the
apylcnoniorphous condition.
the network in the tmipharkyochrome (H'Us, in which tiic in-
tensely stained radiating nodal points of the network are con-
TIIK IXTKUNAL MORl'IIOLOOY OF NKURONES.
11!>
nected in the cull body by (U'oply staiiu-d wry thick bridges,
so that a further connected network of very deeply stuinable
sid)stance is observable. Both enarkyochronie and ainphar-
kyochronie cells are, accordin<^ to Nissl, widely (listrilttitcil
throutfiiout the central nervous system. ^JMie former occur in
the sjjinal cord, but are most munerous in the large dorsal
nucleus at the proximal end of the medulla (Fig. (iS).
,.'\
;iiri
\
Kid. 70.
Fio. 71.
Flo. 70. — I,arf;«' <'t'n IVoin .\iimioir.s liorii of i-.iMiit. ( Al'tcr Nissl. ) Siiniiitocliroinp
nerve cell ol' stieliofliniine variety in llie iiyknoinoiplmns eonditidii.
Fl<i. 71. — Xorve cell tViiui Kiinjilinn on dorsal root of a cervical nerve of a nibliit.
(.M'ter Nissl.) Sliclioclironie nerve ci'll in apyknoniorplions condition. Two
lar^e luudeoli are shown williin the niiclens. TlK'axoneat the upper end of
the cell is .seen to contain iKine of the slainahle snhstanci' of Nissl.
In the second nuiin grou|) of somiitoclirome nerve cells, the
stichochrome cells ((rrtx"?), the sttiinable substtince is arranged
in the form of striin which run in the same direction and usu-
ally parallel with the contour of the cell body, in part tdso with
120
THE NKRVOrS SYSTKM.
i ( .
I:
•!l
i: I
■
-.\
the surfiK'C of the nucleus. Tlicso striiv, as ii rule, arc not con-
tiniiotis filn-ils, hut the striated arran<feTuent is (h'])eu(h'iit in the
main upon diU'erent stained eU'iuents, threads, spindU-s, and
granules, more or less isohited and in rows. These various ele-
ments, without heing direetly con-
tiiutous, arraiifjfe themselves in rows
running in the same direction
within the coll hody. Oocasioually,
in this group of m-rve cells, there
occur examph's in which here ami
there a thread or a row of granules
assumes a direction opposite to that
of the general .striation, an apiJCJir-
anee, however, which would not
prevent the cell from heing included
in this category. So far, Nissl has
distinguished four types of sticho-
chrome cells, represented hy the
m'Fve cells of motor nuclei ( Fig. (!!(),
the large cells of Ammon's horn
(Fig. 70), certain cells of the cere-
bral cortex, and spinal ganglion
cells (Fig. ;i).
The third group of somato-
chrome nerve cells includes those
of the so-called arkyostichochrome
type, in which the striated appear-
ance is united with a networklike
structural character in the most in-
tinuite maniu'r, so that one can
not decide which mode of arrange-
ment of the stainahle suhstance is
most characteristic of the cell.
\issl cites as a typical example of
Fi(i. 72— I'lirkin.jc (••■ll (Voin tiw ('cUs of this sort the J'urkinje cells
'.Yr;''',''\i'T'!'V"'',!l','' 'i',''';"' of the cerehellar (iortex (Fig. 7^').*
(Alter .\issl.) SiPtiiiituchi-diiic \ r> • /
iicrvf cill of the iirkyiisti.iKP- Lastly, as a fourth group of
chroiiic variety ill till- iipykiiti- , ,' n i-. i
morphoiis coiKiitiiiii. somatochrome nerve cells, ^issl
* Nissl in a rccriil uiliclc (AUg. ZtsL'lir. fiir Psychiat., Hcrl., I5il. Uv
(1807), S. 101) liiis {fiveii up the term " arkyostietiochroine " and iiiehides IIk^
cells formerly clussud in llie arkyDslicliochromu groiiii among tho arkyo-
iiH
^^
TIIK INTKHNAL M<>l!IMI(>L()(iV OF XKl'HONES.
I'Jl
(U'scrilu's tlic {^ryoclironic (ypv) type, in which the stiiiiiahle
eoiistituniit of the cell Itotly is ciitirt'ly iriudi' up t)l" siiiall j:;rim-
iiUis. The {^runules iir(( not (listrihutcd, however, at random in
the cell hody, but tend to form threads or h('a})s, so that a dis-
tinct habitus can be attained. Nissl does not jiive pictures of
cells of this type, but mentions that they are particularly,
though not exirlusivi'ly, found in the corpus striatum.
The whole series of types as revealed by his method nniy l)e
classified therefore as follows :
A
(Jitori' I. SoMATOciiuoMi; Xkkvk ('i;i;ls. — Cells in which the
cytoplasm surrounds the nucleus completely and exhibits a
distinct contour.
A. Arki/dchronK' /irrir rclh. The stainable substance in the
cytoplasm appears to be arranged in the form of a net-
work.
1. Type of enarkyochrome nerve cells.
2. Type of am})harkyochrome nerve cells.
;{. Type of arkyochrome olfactory nerve cells, etc.
B. S/ir/iorltroinf iicriw ci-Ux. The stainable substance in the
cytoplasm is arranged in the form of strij)es running in
a similar direction.
1. Ty])e of motor nerve cells.
8. Type of large stichochrome cells of Amrnoji's horn.
3. Ty})e of stichochrome cells seen in the cerebral cortex.
4. Ty])e of nerve cells in the sj)inal ganglia, etc;.
(J. Arh-!iosfirli(trlirt>nii' nrrir ri'lls. Of these, uj) to the pres-
ent, only one type has been distinguished; this would
now be classed by Nissl among the arkyochrome cells.
1. Type of I'urkinje cells of the cerebellar cortex.
D. (iri/dc/iroiiic nerve reli.s.
fjRoup 11. All Nkkvk Cklls not fallixo in Choii' I.
A. Cjilurhroiiie nerve cells. Oidy trac^es of a cell body are
{)resent. The nucleus is of the size of the nuclei of
ordinary leucocytes.
1. Cytocdirome cells of Type a.
2. ('ytocihrome cells of Ty])e ^, etc.
(^hromc pcUs. Ry far the majority of all the norve cells in the body fall in
the arkyochrome group.
X.
(,
I
m
^
, 1
'
'i '
^ ■
!
I:
lij
1 '
1'
til?
;
h\
122 '^'HE NKIIVOUS SYSTEM.
Ji, (hri/or/iromr uorve mllx. Only traces of ii cell body are
prost'iit. Tlie nucleus is of tlie size of onliuary uerve-
cell nu(!lei, and is in every case lar<jer than the nuclei
of the glia cells.
1. Caryochronie cells of Type a.
'Z. Caryochrorno cells of Type /8, etc.
It is Xissl's belief that this classification will, without l)eing
forced, include all nerve cells which can be found, althou<j;h it
it is not impossible that further study may reveal forms which
will necessitate an extension of the numl)er of types, lie lays
stress u])on the fact that between tiie sin<fle types transitional
forms exist, sometimes renderin<; classification diiticult. lienda
has urj^ed this as an ar<jument against the existence of definite
types, but without, as it would seem, any sufiicient proof. The
justification of the chissiiicatioJi does not rest solely u])()n the
establishment of the existence of tiie single tyi)es of cell struc-
ture, but is based largely upon the circumstance that cells of
a wholly definite structure arc situated throughout the animal
series always in homologous localities. Any one who will take
the trouble to stain nerve cells in dilfereiit regions in differ-
ent animals will be able to convince himself not only of the
existence of definite types, but of their predominance in certain
localities, and 1 can give no better advice to the beginner and
to the doubting than that he study the regions suggested by
Nissl in this connection — namely, the ventral and dorsal horns
of the cord, the ganglion cell groups in the thalamus of rodents,
in the corpus mammillare, in the pons, in the red nucleus, and
in the nucleus of Deiters.
This elaborate nomenclature recommeiided by Xissl must
not, however, be regai'iled as a })ermanent and satisfactory
method of designating the varieties of nerve cells. On the
contrary, it must be looked up<m only as a temi)orary expedi-
ent. If, as is to be suspected, too much stress has been laid by
>iissl upon the importance of his " staiiuible substance," which
we now have some reason to believe represents only a porti(m
of the supply of food stuffs in the nerve cell, snch a classifi-
cation can scarcely hope to stand the test of time. It would b(^
as though an architect should attempt to classify houses ac-
cording to their pantries and cellars, or an anthropologist to
group men as types according to the contents of their stomachs
III
;. ;u
THE INTKKNAL MOKlMlolAXJY OF XKl'UoNKS.
123
and intestines — niothoda of catiilo'juiiiji usi'fiil ciiniiffli at times,
perliiii)s, but scarcely to be b)oke(i upon as ideal or permanent.
Ni.ssl early jjoiiited out tliat tbe sin^jle tyjx's of nerve cells
may uuder certain circumstances sliow dilTerent staining rela-
ti(»ns ; * tlie individual members of a given group of cells l)e-
l(mging to one type may bi' palely, moderately, or intensely
staiiu'd. Tliesc dilfcrences appear to depend uj)on the concen-
tration of the stainabh^ substance in the cell i)ody. '. si con-
secpiently designates the extremely darkly stained cells us
pjlk'nuniorplKtHs cells, or cells in which the stainahle portions are
arranged relatively most closely (ttuki/os), while the very feebly
stained cells he names fijn/k/i(iiiH)r/i/ionf< — that is, ^.I'Wa in which
it is characteristic of the staining that the stainable masses are
not arranged close to one another, but are tolerably widely sep-
arated by the non-stainable constituents of the cell body, in-
termediate stages Nissl groups iiAjxinr/if/li'i/oiHor/i/Kiiis. Klesch f
described these appearances, speaking of r/iromaji/ii/ic cells ami
rJt rdtiiop/ioijic wlhiiHwoW as transition forms, and attributed the
(litferences to variations in the interiuil chemistry of the cells,
which depended in part, he thought, upon ditferences in the de-
velopment, in part upon ditferences in metabolism or of function.
Xissl goes further, and mentions that not infrecjuently the
nucleus shows modifications which correspond in greater or
less degree to the staining intensity of the cell body — for exam-
ple, in the apyknomorplious cells the unstained nuclear juice
is relatively more abundant than in the pyknomorphous exam-
ples, in which, as a rule, the nuclear frainework and the stainable
parts of the nucleus generally are relatively more abundant.
This holds, he asserts, not only for the somatochrome cells,
but also, though in less degree, for the caryochrome and cyto-
chrome cells.
A curious and puzzling phenomenon is met with in the so-
called cliroitiopliik'X nerve cells (Fig. T-\). One sees often.
* Alls, /^tschr. f. Psyp'ii'it.. Ht>rl.. Bd. 1.
•f Flcscli. M. I'oIhm- (lie VcM'scliicdonlioitcn im chemisclKMi Vorlmltcn dcr
XiTvi'iizi'lliMi. Mittli. d. iiiiturl'. (icsollscli. in Horn (ISST), Xr. 1 H)!)-ll!)4, S.
li)2-li)!). Hi^in, I*. Ibiller. t88H.
X Tlio word c/ininiopln'le is hi>ro nscd in tin' sonsc in \vlii('li Nissl cinploys
the torm ('lirttinophiliv (Xissl. Allj,'. Ztsclir. f. Psyclii!it..<'tc.. Mcrl. (iHlHi), I5d.
Hi, S. H). WliothiT or not, this is the sensi- in which tht; word is employed
hy Plesch and his pupils is not dear.
"m
■V:' !|
•iiPi
124
TIIK NKIJVOI'S SVSTKM.
I I
■ ;»♦
[
1 ' .<
,
i :
!!
•,i\(m<s vvitli tlic otiicr nerve cells, siii<:le cells or siimll groups of
cells ill ..liicli the stJiiiiable siil)stiiiice !i|)[>e;irs to l»e eveiilv
(iill'used t liroii;_'lioiit the cell ho<ly, so thiit it is iiii|)(»ssil)le to
(list iii<riiish ii stiiiiiiihlc from an iiiistiiinalile eonstitiieiit in the
cell. 'I'he expliiiiiition ol' these forms is as yet not entirely
satisfactory. NissI points out that they are always relatively
stnaller than pyknoinorphoiis cells. It is nearly always j»ossible
Fui. 73. — Xcrvc ceil IVoin tlic s|)in!il conl of the doj; in tlic so-called "ciiroino-
pliilc" coiKlilioii. This uiiiiciiraiicc is iit least in the niii.jiirity <il' iiistanees an
artefact due 1(1 the actiiiii of the reajicnts etiipld.ved. The axdiie here, as in
other nerve cells, appears to he free from tiie stainahle siihslaiice.
ii'ii
I
f M
m'
to make out in alcohol ))reparations, as I have had many opjior-
tunities of observinij, that at th(^ i)eripliery of the sections
ehroino}ihile colls tend to he iiltundant, and there is no donbt,
in my mind at least, that the majority of these corre-'iond to
the well-known artefact.s which are so common in the peri^thery
of tissues hardened in alcohol. But the chromophile cells are
not entirely confined to the periphery of the sections ; they niay
occur singly or in little <iroups in almost any portion of the
tissue ; it has seemed to nu', however, that even then they are
IP
TIIK IN'TKIIX.M, MOIIIMIOLOOV (»K N'KUllOXKS.
1 -2:
Mion' iiltiiiHliiiit ill tlic iici;,'lilM)rli()oi| of llic hluoil-vt'sscls or
liirfjcr tissue iiitrrspiiccs, and it is not iinpossiltic t liat iiitlics*'
situiitioiis tlR'V limy represent artefiuits due to tlie iietioii of tlie
iileoliol. N'issI liimself does not seem entirely 'dear as to tlieir
nature, liut lias recently expressed liinisidf as of the opinion
that thoy lire in hir^'e part due to the action of reajfcnts ein-
jiloyed, alth(ni<^li IumIocs not deny that under certain eircuin-
stances they may have a [lathological riij^nilicunee. For the
Fi(i. 74. — Mnlor ncrvi' cell iVuni llic vnitriil horn oC tlic {iniy iiiiittcr of tiio siiiiiiil
(•()r<l 111' the (liii:. St:iiii('(l liy llcld's iMiiditicMtiini of Nissl's inctliod. Tlii'
tiKi'oi'l liodits ;mi' di^tiiiitly visihlo in tlio pi-olopliisiii ol' llic cell liody, anil
(■s|ir(ially ill ono of iju' dcndiilis. Tlii' :ixonr is not sliown. Tlir lioidiis nf
tlir niiiiiiis iiir indislinrt. iiwinii Ik overlying iylo|ilMsm. Iml the siiiulr.
deeply sliiiiiiii niiiieolns is very evident. Owini; lo llie limits of the piioto-
graphii' method. I he stiintmes at only one foeiis simw eleai'ly.
present, liowever, inasmuch tis they vary so markedly in a]ipear-
ance and loi-alization that no normal c;in he estid)lished for
them, lie su,<j<;ests that in the study of patholoj^ical alterations
only those ohservtitions are of value whitdi we know for certain
to have been made upon cells whitdi are not chromophile cells.
A further study of these aiipi'tirances is urgently needed, and it
iiilii
^ijii
4
f
126
Till-: NKIIVOUH SYSTKM.
is to !)(• liopcd Mint ere loii^' we Hhiill Imvo a (^louror conopption
ri'^'iinliiiff tluMr Hif^tiifK-aiicc.
Ill Kijf. 74 is shown a ncrvo ju'll frotii the spinal conl of a
ilo^'. The plioto^'rapli wliicli Dr. A. (J. llocn has kindly made
lor nic shows very Wfll the appearanc-es to be made out under
relatively low powers.
i i
U
li
"\
ill
•o
CTTAI'TKU MI.
TIIK NATUKK OK TIIK TKiHOID MASHKS OK "8TAINAULK SIB-
STANCK" or NISSL.
Nalun^ of tli(' "stiiiniiltio siilfstiiiifp" of Nissl — Views of Nissl, Fit'iiilii, Rosin,
hikI lli'Ul — llclil's iiiodificiitinM of Nissl's iiictliod iitid llic n.'siilts yicldcil
by it — The iiitlnoiicc of clu'inicai ri'iip'iils mul of dij^fstivu lluids ii|ioii
the Nissl liotlics — Studies of Miiciilluin luul Scott.
In niodlcino, as '" thcolofjy and j)liil(»s(ipliy, tlio suhjiu^ts
which are moHt interi'stinf;; and most (liseusscd an; those a.jout
which we know least, and it is not surprisin<;, therefore, con-
sidcriiifj the scantiness of our knowh-d^^e, that the nature of
these stainabk' portions of tlie sul)stance of which the cell l)ody
is made up should have been the subject of much polemical
writiiif?. Indeed, between Nissl on the (me hand and Uosin
and Henda on the other (the two latter not beitij;, however, en-
tirely in agreement), a battle royal has been carried on in a
series of articles in which too often personalities, tiresome to
read and unworthy of the disputants, have been jiermitted to
enter. Missl has taken the ground that for the present, at
least, we have no rijjht whatever to make any posit'.vc state-
ment re<fardiji<f the chemical nature of these substances; he
urges that for the time being we must remain content with a
description of the mor])hological appearances met with in the
specimens. His terms, "visible formed substance" and "or-
ganized substance," as ap{)lie(l to the stained pctrtions of the
cell body, introduced with the idea that they are i)urely ()l)jec-
tive, are in reality not so, and are, therefore, uiulesirable. To
the term "staimible," if by this is meant "stainable by Nissl's
method," there can be no objection. Rosin,* whose studies
were made largely with the triacid stain, having in mind the
principles of elective staining formulated by Ehrlicli, compares
* {{osiii. II. I'diiT cine lU'Ue Fiirhinifisiiii'thode dcs f,'i'sammtt'n Ncrvi'ii-
systi'iiis iH'ltst Hi'mcrkuiificn iibcr (iaiijjlieiizciifii uiid (tliazclii'ii. Neurol.
C'entnilt)!., I.cipz., Hd. xii (IH!);}), S. 80:5-H()i». Also. EntRcj^'iumj,' auf Nissl's
Benierkunj,'i'n, etc. Neurol. Ceiitralbl., Leii.z., M. xiii (1H!)4). S. 210-214.
137
■■----11
:«■ i!
ifti
ili
ft'
'I
f
*
\-2S
'I'llH NHHVOIIS SYS'l'KM.
the <,'riuuili's within the nerve cells — tliat is, the stiiiiiiil)le sul»-
stiiiiee of Nissl — with the l)as(»j)hih' ffraiuiles of the Maslzrllni
of Khrlicii, and concluth's from his studies that th(^ <(ranule in
the nerve cell is to he tliought'of more in a chemical than in a
nior|)holo,<,ncal sense. Henda, as rcfjards the jj^eiieral si,<i[nificance
of staining reactions, supports Rosin. Nissl has opposed Rosin's
view, and has urged, first, that not all basic dyes will stain th(>
substances contu'rued, and secondly, that certain iund dyes will
stain them intensely, objections which he believes uj)set entirely
osm s view nased
H
that
on
IhrlicI
1 s "olor
tl
Dasic (lyes, iiKe m(
lik
•thvlt
u'or
d tl"
It IS certain
cue /.ue and tluonin, stain very
beautifully the Nissl bodies; indeed, the nu^thod of Xissl de-
l)i'uds u])()n this quality; but Nissl contends that the term
lUtsiipliilii' A\o\\\{\ be used oidy in the sense in which it has been
previously deliiu'<l hy Klirlich, in which (tvent it is impropcir, lu;
thinks, to apply it to the stainable substaiu-e of nerve cells.
Kosin separates the " granules " in nerve cells from other
basophile cell substances on account of their behavior toward
the triacid mixture;* and Meiida iiudiiu's to the view that the
granules in the nerve cells approach lu'arest in character to the
8-granules of Khrlich. He asserts tliat in numerous experi-
ments with his method (formol freezing) he has found in the
most diverse organs constituents of the cell body wbi(di Ix!-
luive, not only tiiu'torially but also im)r])hologicallv, exact Iv as
the stainal)lc substances in lu'rve ce
le (lescnhes
then
1 in
gland cells, liver cells, in cells of the pancreas, in the (^ells of
sor.G sarcomatous tumors, in certain conuective-tissue cells, but
es])ecially in normal and pathological ,ym])h glands. Ramon y
C'ajal f also assi-rts that the stainable sul)stance of Nissl is not spe-
cific for the nerve cells, as he has denn)nstrate(l its presence in
certain of the leucocytes ami of the connective-tissue elements.
A flood of light has been thrown iijxm this |)ortion of our
subject through the recent researches of Hans Held. J Held
has studied the structure of nerve cells of dilTerent animals in
a large numbei- of tlilTcrent regions with a ■ modification of
NissPs nu'thod, which he has hims(^lf devised.
* Nourol. Cent rail)!., L(M|)/., \V\. xii (IHilH). .S. H0«.
t IJami'iny Cajal.S l''.siriiclin'ii del pni|ii|ilasiiiii iicrvioso. IJcv. triiin-sl.
niicrdir., Madiiil. vol. i (is'Mi). ])|i. l-:!(i.
X Ili'id. II. licit lii^'f ziir Stnictur dor Xcrvcnzcllcri iiini ilircr Furtsiltze.
Art'h. I'. Amil. mid IMiysiol., ,\iiat. Ablli., Lcip/. (IS!),")). S. ;j'JG-41G.
TIIK INTI<]UNAL MOIUMIOLOCY OP NKUUON'KS.
120
His niodificiitioii, whicli 1 liavo used invsclf ;iii(l of u liicli 1 can
•spoiik ill till! liiyliest tcniis. is us follows : Tlic tissues are imbedded
ill iiarfilliii, iiotwitiistaiidiii;,'' Xissl's ol)Je<'tioii tiiat iiiilM-ddiiij^- in-
jures tile nerve-ceil sti'iiclure. Held has found, and I can conlirin
his stateinenl. that witli careful parailin iinl»eddin<,'' no more arte-
facts are produced than when no imheddinjr at all is employed.
On the contrary, it is possilile with paratlin to obtain sections as
thin as oiu^ micron, or even thinner, wlu'reas sections prejiared by
Nissl's mt'tliod are sehloin thinner than fioin seven to eij:ht mi-
crons, and it is liy virtue of the jiossibility of oi>tainin;4' thin sections
that much of the increase in our knowleilji'e of the nature of the
staiiiable substances inside the cell has resulted. In order to study
ordinary palholojjfical alti-ratioiis in the cells, however, .sections
from six to twelve or even thirty microns in tliickness utTord the
most .satisfactory r(>sults. Held fa.stens the parailin se<'tion on the
slide with dilute alcohol : the staininj^ Huid consists of ecpial parts
of Nissl's solution of methylene blue and .soap and a tive-pi'r-cent
acpieous .solution of acetone. T\\v .sections are heated in this mix-
ture until all smell of acetone has disappeared. (Held stains tirst
with a solution of erythrosin. the erythrosin servinji' to brinji' out
the other constituents of the cell body, the iioii-stainai)le substance
of Nissl ; for tlie study of the Nissl bodies alone this portion of his
nietbod can lie dispensed with.) The sections, aft(>r stainiufj', are
allowed to remain in the blue solution until it has cooled, and are
then dilVerentiated in a one-tentli-of-oiie-jier-cent solution of alum
for from a ft'w seconds to a few minutes, accordinj;' to the thickness
of the section. The sptH-imens are then washed in water, debydrjited
quickly in absolute alcohol, cleared in xylol, and mounted in beii-
ziiie-colophoiiiuni. H(dd used as a fixinsr ajrciit sometimes ninety-
six jier cent alcohol and sometimes picrosulphuric a<'id, as the latter
shrinks the jirotoplasni less. Tn usiiiy this lixini:' ajrent, however,
very small jiieces must be em])loyed, as it penetrates with dilli-
culty. It has been stated by some that staiiiiiiji- with tlie blue
solution for twenty-four hours in the cold <i'ives results fully as
.satisfactory as when heat is employed. M. IJettmann, workinji' in
this laboratory, tinds that artefacts are much more fre(]uent when
liiji'h temperatures are (>mj)loyed. He has obtained his best results
by staiiiiiifj: for twenty-four hours at a temjierature of MT' t'.
Another excell(>nt modilication of Nissl's method is that of
Mann, of Edinburj^^h.* Sections of sublimate tissues are stained
with a concentrated a(iU(>oiis .solution of toluidin blue. They are
then diU'erentiated, and may lie counter-stained if desired. The
* Miuiii, (i. Uelior (lie Heliiiii(llim,>r dcr rt'iizcUoii fi'ir expcriiiii'iitcll-
hist()l(>;;is('lio UntersiiciiungLMi. ZL^^clir. f. wissLMiseli. Mikr,, 15nisi:li\vy„ Bd.
xi (US04), S. 4T!t-4y4.
'ifil
130
TIIK NKIIVOUS SYSTEM.
ii
!'■ !
ilir
I
i(
u
m
t<)hii(lin-l)lu(' iiiotliod lias also been iisod by von Lonhossc'k * witli
satisfaction, and rcci-ntly Harris, of Pliiiadeli)]iia,+ lias publisiiod an
article in wliich ho jjives a innnber of interesting details with re-
gard to his modifications of this method of staining.
Held finds in sections from one lialf of a micron to one mi-
cron thick that the tijjjroid bodies present an ex(|nisitely granu-
lar structure (Fig. 75). With liigli pow-
ers tliey are seen to be made up of masses
of granules, some of the constituent
granules ])eing very small, others very
coarse. They have a rounded form, and
when not too close together ajjpear in
rows and radii. In some cells, where the
constituent granules are very close to one
another, a granular structure is recogni-
zable only in extremely thin sections
with the aid of strong immersion lenses
and favorable illumination, liut Held
, ,-,.,., , • maintains that in reality all ar(M()mi)osed
•<:^h. #..^j ot granules. In some cells the granules,
-v*'" instead of being grouped in clumps, ap-
Viy,. 75. —('.11 of vontrai p^..^. jq \jq more or less evenly distributed
licini cif j;i"iyiiiiittcr<ii liii- *^ ^ ''
man spiiiiii t.pid. (After throughout the wliole of the ccll body.
Held.) Tlic tissue lias j • , .,, ,, ,,
lieeii fixed in pierosiii ^'» nii'iiv iiistanccs witli the crytliro-
j.hiirie aei.i a"<l jm- siu-mctliylenc-blue stain the granides
neddeil III |>araltiii. See- .•' . ^
tiims<iiieiiiien>iiin tiiiek- are not In contact with one another, but
iiess. Stained with ery- ■ i i i i • i i-i
tlirosin and iiietliyleiie 'l^'t* nnl)cdde(l HI a coiigulumlikc niiiss
which stiiins violet iind is easily distin-
guishiible from the bright blue of the
griinules pro]»cr and the red of the ground
substance — that is, unstainable substance
of Nissl — lying between the tigroid bodies
so that lleld dcscril)es the tigroid bodies as being uukk' up of
two constituents, one griinuliir, the other coiigiilumlike, with
sometimes a third — ntimely, the vacuoles.
* von Lenhossek, M. Uebcr den Huii dcr Spiiialgunglieiizellen ties
Meiischen. Vortrag iiuf der Wiuidorversiuiunlinig siidwcstdeutsclier Neii-
rologoii. Madeii-15adoii, IHJIG. Areli. f. Psyeiiiatr. u. Xeiveukr.. Herl.. IM.
xxix (1896-'9T), S. lUO-IiSO.
t Harris. H. P. Two New ]\rc'tliods of Staining the Axis-Cylinders of
Nerves in the Fresh State. Some Microi'liemieal Keactions of Toluidiii-
Blue. Philu. M. J., vol. i, 18!»«, pp. 8!»T-!)(K>.
Iiliie. Tlie Nissl bodies
are seen to lie made up
of masses of miiiut<' unin-
nles. Tlie liiM' f;raiiiila-
tioii of tile Ki'oiind siili-
staiiee is also aiiiiareiit.
to
iir
TIIK IXTEHNAL MOKIMlOLOOY OF NEUUOXES.
I'M
Held (k'scril)i's in detail his study ol' fresh <iaii^'li()n eells in
piiysioU)<iieal salt suliitiou and in vitreous humor. Kx('e[)t tiie
flat gniy glistening nucleolus, with sonietinu'.s a vacuole and
accessory nucleoli, and a homogeneous transparent nucleus
limited by a mirrow, (loul)ly contoured meml)rane, nothing
could be made out. A few (hirk granules only could be sei-n
within the jtrotoplasm, even in the most favorable cases, and he
asserts tlnit when he worked ((uickly the protoplasm remained
almost absolutely free from granules. The tigroid bodies are
invisible in fresh cells. Held treated the fresh cells with vari-
ous reagents in order to make out, if possible, the action of
swelling and fixing solutions upon the structure. He fouiul
that on adding methylene blue in dilute solution he obtained a
result which led him to think that the blue acts upon fresh
tissue as a fixing agent at the same tinu' that it exendses a
staining influeiu-e.* With other fixing agents Held obtained
dark masses after vacuoliza- ^. ^
tion, which he thinks represent
the tigroid bodies. lie be-
lieves, therefore, that we have
no right to think of the tigroid
bodies as of an organized
na-
ture or as representing pre-
fornu'd cell organs. Hasing
his experinu'Uts upon those of
Fischer concerning the mode
of action of fixing agents, he
thinks that tlu; tigroid bodies
represent simi)ly substances
precipitated from solution by the action of the fixing mixtures.
They are not visible in fresh protoplasm, but dark nuisses cor-
Fi<;. 71). — Xcrvc ('(11 from Dcitrrs' ini-
clt'iis ill the nilihit. Scctidii three
iiiicriins tliick. Tlic tissue has heeii
expciseii to the digestive iietidii <pI' :l
iiiixliire 111' pepsin uikI hydidehhiiie
iiciil Ml inc. I'm- twelve hems. 'The
fjrciiinil siihsliiiiee has lieeii dissulved
cillt 1111(1 the Nissl licidies ahille le-
iiiaiii. (.M'ter ll(dd.)
* In the liistolof;;it'iil course in the Johns Il()]ikiiis Medical School the
treatment of fresiily tiuised ventral horn cells with nicthyleiie blue is now
('iii|)l()ye(l MS one ciisy anil satisfactory moilc of (leinoiistnitiiie; the tij,'i'oid
bodies in the cell lioilics, and especially in the dendfites. I iiave, re|K-atedly
convinced iny.self of the honioffeneons appearance of the protophisin of the
nerve cell when it is e.Nainined iiiniicdidti/i/ after removal ffoiii the liviiifj
body. Only after the lapse of a cer aiii lime do masses which correspond
to the ti'^roid bodies become visili
■itand the statements
if Fl(
1 am
d von
a loss, Iherefore, to nnder-
Leiili
lioth
invest iirators
iiiiown for their accuracy and olijectivity, wiien they assert tiiat llu'y have
observed the ligroiil bodies in fresh living cells.
.'
. :'
1
i
ll il'^
i
i
*
'j
n
I
,1
•i'
:^i
V3'2
THE NKIiVOUS SYSTEM.
respondiiij:!; to thorn are obtiiiiiod on the addition of fixing
rea,ueiits.
Held undertook a most carel'ul and exaet eheniieal study of
tlie granule>- in alcoiiol tissues. Thus, he found that the ti-
groid bodies are insoluble in
dilute and concentrated min-
eral acids, in aeetic acid, boil-
ing alcohol, cold or l)oiling
ether, and in ehloroform.
On the other hand, they are
easily soluble in dilute and
concentrated alkalies. With
pepsin-and-hydrochloric-acid.
digestion he found that the
ground mass of the jiroto-
plasm vanished and that
the tigroid bodies alone re-
mained undigested (Kig. 7(i),
the reverse of what octmrred
on treatnuMit with lithium
( Fig. rr). The tigroid bodies
yielded no reaction with Mil-
Ion's or Adamkiewicz's rea-
gent. Held obtained, how-
ever, slightly positive results
with Lilienfeld and Monti's
mieroehemical test for phos-
])boi'us, and a considerable
«|uantity of the gray nnitter
of the s])inal marrow after
digestion with pejjsin and
hydrochloric acid examined by Siegfried, of the physiological
laboratory of Leipsic, showed the presence of phosphorus.
Held concludes, therefore, from these various reactions, that
the Nissl bodies belong to the group of the nucleo-all)umins, a
view whifdi agrees with the investigations of Halliburton, who
found in the gray matter a nucleo-albumin which coagulated
at from 55° to 00° ("., ami which contained as much as 0.5 per
cent of ])hosphorus. We have here in Baltinuire tested the
tigroid masses a nund)er of times for the presence of iron by
Macalluni's method, always with negative result. Warring-
I'"i(i. 77. — Ncrvo ct'll t'niiii tlic };i"i.V iiiiittcr
of tlif liniiliiir ciinl nt' tlic i>\. Alcolml
tixatidii. 'rrcatiiit'iit lur t'lmr dnys in
finicciitratcd aciiicdiis suliition nl' lilli-
iiiin carliDiiatc. The Nissl l)ciilifs have
Im'i'II (lissol veil (iuI, and llic }i!'iiiiii(l slll)-
slaiicc alciiir rcinaiiis. (At'tir II<1(1.)
TIIK INTEUXAIi M()UIMI()I,()(iV OF XKl'IfoNKS.
i:w
ton, too, lias a|)i)lii'(l ,v saiiic tost, but doi's not ol)tain any dis-
tinct reaction Tor iron.
Macallum * liinisclf, liowcvor, aj^pcars to liavo dcnionstratod
tlu! presence of iron in the substance. In his a(hlress before
the physiolof,ncal section of the Britisli Medical Association,
held in Ediid)urgh in July, 1S!)S, he referred to some investiga-
tions undertaken by his j)upil Scott, mentioned tliat iron and
phosphorus exist in the sul)stance, and stated that the Nissl
spindles of the ventral-horn cells resist peptic digestion (as Held
had shown), but that they are slowly digested with trypsin.
He coiududes accordingly that they are of the nature of a
nucleo-i)r()teid. .Macallum has develojied a nu'thod for the his-
tological detection of j)hosphorus which seems to be more exact
than the procedure of Lilienfeld. Instead of using pyrogallic
acid as a reducing agent on tissues previously subjected to
treatment with acid solution of ammonium molybdate, Macal-
lum employs the hydrochlorate of phenyl-hydrazin, removing
the excess with water. The lecithin may be removed from the
tissues before applying the test by placing the slide, witli sec-
tion attached, into a Soxhlet apparatus and extracting with
ether. By this method the portions of the tissue containing
phosphorus assume a dark-green color.
Held believes that these nucleo-all»umins, although invisible
in the fresh protoplasm, are present in it in solution, and that
they first take the form of Xissl bodies when the protoplasm is
subjected to the action of fixing reagents. In further su])port
of this view he fouml that with the ditliTent kinds of fixing
reagents and witli varying coJicentration of the same reagent
entirely different histological pictures of the tigroid accumula-
tions and of the masses lying between them could be obtained. f
* Jlaealluni, H. B. Some Points in the Miero-Cliemistry of the Nerve
Cells. Brit. JI. J., I.ond. (1H!)8), vol. ii. j,. 7T8.
•f For exfun])lp, forty-per-oeiit alcoliol precipitates a part of the tigroid
bodies iniicii more finely granular than does ninety-six-]ier-('eiit alcohol,
while the part of the granules otherwise thrown down in eoaguliimlike
masses is not precipitated at all. so that one sees distinct spaces between the
single line granules in the larger Xissl bodies. As XissI has always empha-
sized, however, for the study of pathological alterations, it matters little
whether the Nissl iiodies are preformed structures existing intra ritinn or
are till" result of precipitation. The important point is that under normal
conditions by definitely uniform methods perfectly constant microscopic
pictures are obtained. Nissl has accordingly introduced the term "nerve-
441
i;{4
THE XEllVOL'S SYSTEM.
If tlicso invcstijxiitioiis of Hold are coiifirnicjl — aiul the accunicj'
with wliicli tliis work lias Iiccji <'oii(lii('ti'(l, as wi'll as that of liis
])rcvioiis coiitributioiis, loaves hut liltk' room for doubt upon
this point — wcMimst admit that his su<i<,'c'stioii that thoy yield
an index to the internal metaholism of the nerve-cell protoplasm
is entirely reasonable, and that thr()u<i;li fixation and stainin«f
»ve can oi)tain an idea of the stock in trade, as it were, at the
moment inside of the nerve cells.
The relation of the stainable substance of Xissl to the nerve
colls of the ventral horns has been studied by Macalhim and
Scott in embryo pijjfs. At a very early sta<je the ventral-horn
cells are found to consist almost entirely of nucleus rich in chro-
nnitin, the protoplasm of the cell being but poorly developed.
At a later period the ci'll body elongates, the nucleus becomes
less rich in chromatin, and close to the nucleus a " cap " of
peculiar nature, stainable witii toluidin-blue, makes its a])pear-
ance. Still later in development this stainable substance seems
to be uniformly distributed throughout the cytoi)lasni, and
linally the aggregations of the substance in the form of the
spindles met with in the adult are encountered. Macalhim and
Scott, therefore, are of the opinion that the ^'issl bodies are
derived from the nucleus of the nerve cell.
%
I
■u
cell (Miiiiviilciit " or " t'(|iiivii]t'iit picture " (AeqniriiUnlliilil). By tliis lio tiii-
(k'rsliiiids the iiiifroscdpif pirliirt' of a lu'rvc cl'H [ircsfiil in tlic tissue uf an
animal killed in a prcseribeil way and at'tervvard treated l)y a deliiiito method
of jireparation. lie thus does not concern himself with tlie way a iicaltliy
lun've cell of livinj^ or dead tissiu' looks, hut ever bears in mind a certain
constant — namely, the " (Mjuivalciit form" id' the healthy ncrvc^ cell of the
dead tissue. Any deviation from this normal '• ei|uivalent jiicture " of the
nerve cell would indicate some alteration in the latter, and it is in this
way that the alterations under i)hysiologieal and pathological conditions
can he ilcscribed and judged.
C'IfAITKU XTTT.
Tin-: (innrxi) si-iistanck oi; " rNSTAiNAiu.K sntsTAXci: "
Ol' MSSL.
Niitiirc cif tlio " uiistiiiiial)lo substance" of Nissl — Acidoiiliilc n-nctinn of
Hosiii — Comparison witli sarcoplasni (IJcnda) — Fibrils in tlic "unstain-
nble snbslani'o " — Meeker's lindings in ventrai-boi'n cells — Studies of
Apiitliy and Hethe — (tol{j;i's cndoeellular network — Ileld's observations
with erythrosin staininj; — Tlie structure of axones — Tlie axospon^iuni
— Xeurosonies — Studies of M' 'iilpmuTV— I lypol lieses coneerninir the
conducting substance — Tlie presence of centrosonies and attraction
spheres in nerve cells — External reticular covering of jierikaryon and
dendrites.
Ti-' WO jire loft in doiil)!, tlioti, as to tlio oxact nature and sio--
nificance of tho portions of tlio norvo-ccll ])0(1y stainahlo liy
Kissl's motliod,* wo afo in a still groator diloninia as t'cfxards
the chafactor of tlio non-stainable pai't, tho visiblo unforniod
substance of Xis«l. AVhilo Xissl liitnsclf lays groat stress u])on
tho significance of the staiiuible substance, ho grants that tho
non-staiiniblo substanco, or ground substance,! is probably just
as important, indeed, ])ossibly of much greater consequence.
The quatititativo relations of the two substances vary enor-
mously in ditforcnt nerve cells, almost as mindi, porha])s, as do
thoir position relations. In the largo motor cells of the ventral
horns, for example, and in similar cells in the formatio reticu-
laris, the stainable sulistatu'o of Xissl prepoiulerates by a con-
sidoral)lo am(nint ; in the I'urkin jo colls of the cerebelhun, in
tho pyramidal colls of lU'tz, and in many other nerve cells, it is
the ground substaiu'o which is often by far tho more abundant.
liosin's studios I'onvinced liim that the ground substance of
nerve cells had a distinct elective affinity for acid dyes ; ho
therefore speaks of this portion of the cell body as acidophile
as contrasted with tho basophilo constituent, by which ho moans
the stainable sul)stance of Nissl. The majority of investigators,
* FlemniiiiL''s Intertilarniusso.
■f I'^lemniing's Filarniasse.
135
1 ('
M
M
lit!
!l ?
/i
^
I
fUi
i;u;
TIIK NKUVors SYSTEM.
: ;
l)iiL l)y IK) nu'aiis all, arc ajrrctMl that tlic ii()n-staiiial)li' siil)staiU'o
(if tilt! cell body is closoly allied to, if Jiot identical in structure
with, that of tho iixone and of tiio axone hillock. Others, how-
ever, look upon the axone as a specifically dilTerentiated jiortion
of the fran^^dion cell hody, ditVerinff entirely from the rest of the
cytoplasm in structure. Benda has advanced a numhcr of in-
teresting hypotheses in this cojinection, conijjarinj^ the histo-
genesis of the nerve cell ami its processes to the development
of the striped muscle fihre. The cells which ^nve rise to mus-
cle tibrcn, the so-called sarcobhists of Marchesini, contain a
protoplas'.n which, in part, becomes ditferentiated to form tho
muscle tibrils, but in small amount persists as the so-called sar-
c'jpiasm of adult muscle. Menda descril)es the neuroblast of
llis as being made up of protoplasm and of j)araplasm,* tho
latter belonging, according to him, to the non-stainable ])or-
tion of the nerve-cell body, lienda thinks that the protoplasm
of the lu'uroblast in tlie course of development is in j)art dif-
ferentiated into a tibrillary substaiu-c constituting the nerve
fibrils of the axone as well as jjortions of the cell body and
dendrites, but in i)art remains unditfcrentiated, even in the
fully developed nerve cell, as basophile neuroplasm, (juite
analogous to tho sarcoi)lasm of muscle. A'issl has objected,
that these views are purely hypothetical, and states that the
developnu'iital course of a neuroblast can not be brought into
analogy with that of a sarcoblast. Apathy, when descril)ing
his "nerve cells " (as opposed to his "ganglion cells "), states
that they produce neurofibrilhe just as muscle cells produce
muscle tilirillic. He also compares " nerve cells " with muscle
I
* Von KiiiifliT (l^ebcr r)iiriT('ii/iriiii<; dos Protopliisinas an den Zellou
thicrisclior Gewebc, Schrift. d. nudirw. Ver. f. Schlcsw.-IIolst., Kid, Bd.
i, 1875, II. ;5, S. 2'2i)) first t'oiitrastcd the '• pnitojilasin " witli the " para-
plasm " of cells. He used thi' word proto|ilasin to indicate the internal
or endoplasmic portions of the eell body — that is, those adjacent to the
nnelens — while the word [laraplasm desij^nated the peripheral ceil plasm.
The terms had therefore oidy a topofjraphieal sij;nifieation and had no ref-
erence to the finer protoplasmic strnctnrc, as have the words mitom and
paramitom, sponsioplasm and hyaloplasm. ]\[any histolojjists have failed
to recognize this fact — Henda, for example, (pioled here, uses paraplasm in
the sense of paramitom. In a recent article (Uebcr Energiden und para-
plastis('ht> Hil(liini,''eii : Rektoratsrede, ^Jiinchen, lH!)(i) von KiiplTer himself
uses protoplasm to indicate tlie jirimary ukI active part of the cell, anil re-
fers to para[)lasm as the secondary or passive part.
TIIK INTKUN'AL MOUIMIOI.OOY OF NKrUOXKS.
1:57
(•ells in their liistogi'iiesis, and licliovt's tluit ii " nerve cell " is no
more cupable of tiie hi<;iiest fniietions of condiietion l)efore tlio
apiieariiiice of the neiifolihriliie tliaii is a muscle cell of the
highest fiiiH'tious of eoiilraetioii before its peculiar lii)rillit'
have been dilTerentiated.
One thing wotihi seem certain, if we have to (h-al in nerve
cells with a fibrillary structure at all, the fibrils must be sou<i;ht
within the " iion-staiiuible " i)ortion (in tiie sense of Nissl) of
tile (H'll. Hecl<er * has asserted tliat he has stained ele(;tively
with hsematoxyl in-copper the substance of tlio nerve cell whicli
renuiins unstidned by Nissl's method, and fiiuls that it con-
sists essentially of a(!tual nervi- fibrils. It represents, he says,
the (lire(!t continuation of the })rimitive fibrils of the axone
into the cell body and the dendrites, an idea which approaches
closely to that advanced by Max Hchultze. liecker's studies
were made upon the motor cells, and Xissl has recently agreed
that the existence of the fibrillary nature of this part of the cell
body has been })roved for these cells. He says, however, that
Becker's method does not suffice for the decision of the ques-
tion in all varieties of nerve cells, and that the nature of the
structure in cells other than the nu)tor cells must for the pres-
ent remain undecided f The wonderful demonstrations of
Apathy of curiously com])lex fibrillary relations in the nerve
cells have already been referred to at some length in Chai)ter
VI, and need not be described again in this place. We await
with considerable eagerness the a})pearance of Apathy's second
communication, in which he promises to compare his own find-
ings with the observations aiul opinions of other investigators.
Stimulated by the results attained by Apathy, Hethe I has
attempted to dennmstrate the fibres in the cells of vertebrates
and especially in human iu>rve cells. The method of xVpathy
does not appear to yield very satisfactory results when api)lied
to the nervous system of higher mammals. Bet he, however, has
* XX. Wandcrversaininlung der si'uhvcstd. Ncurologeu und Irroiiiirzte in
Bndoii-Hadcn am 25. und 26. Mai 1895. Archiv f. Psyeluat. u. Nervenkr.,
Horl.. Bd. xxvii (1805), S. 05;5.
f In a still later article, Nissl, on the ^n-nund o( the preparations of
Apalliy and Bethe, accepts a fibrillary structure for the nerve cells in {i:en-
cral.
I Betlie, A. Ueber die I'riniitivfibrillen in den (langlienzellon vom Mcn-
schen und anderen Wirbelthieren. ]Morphol. Arb.. .lena (189H), Bd. viii,
8.95-11(1.
/I
t ;
h-
w
I > I
138
TIII-; NKK vol's SYSTEM.
.1 ^,
I
111 : '■-
(k'vc'lopt'd 11 int'thotl, the di'tiiils of wliicli iirc not yet published,
whicli stains the lihrils lu'iuiti fully, even in the nerve cells of
man. The prlncipiil points in the method are as follows : The
Nissl bodies are first removed from the .sections by treatment
with ammonia, in which they arc soluble. Later, the sections
are treated with hydrochloric acid, and afterward with molyb-
dic acid followed by toluidin-blue. The tibrils by this method
stain of an intense blue color.
Ik'the has been able to demonstrate the fibrils in dilTerent
parts of the central nervous system in both cells and iibrcs as
well as in the peripheral nerve lil>res. In the axones of the
j)eripheral nerves the fibrils appear distinctly stained, with deli-
cate smooth contour runnin;,' in a somewhat wavy course and
nearly i)aranel to (tne another. Sin<,de tibrils can l)e followed
foi- a distance of lifty microns and farther. They seem to be
imbi'dded in a homoffcneous ground substance. Hethe can
find no indication of the honeycomb structure of Hiitsehli. In
longitudinal sections no transverse fibrilla3 can be nuide out
connecting the longitudinal tibrils, and in cross sections of the
axones the librils appear as isolated points in the homogeneous
substan(!e. The fibrils are more separated from one another in
the axones in the peripheral nerves than in those inside the
central nervous system, apparently owing to the presence of
relatively larger amounts of the honujgencous substance.
The tibrils inside the nerve cells are so distiiu'tly stained that
Bethe is much impressed with their independence. He does
not think that they are actually a part of the protoplasm since
tlicy seem to be so markedly differentiated from the latter.
They occur everywhere in the unstainable substance of Xissl.
Hethe dilfers from Apathy with regard to the relation of the
fibrils to one another inside the nerve cells ; whereas A})athy
describes the formation of fine intracellular plexuses and net-
works through multiple anastomoses formed by the subdivisions
of the tibrils within the cell protoplasm, Hethe is of the opinion
that the fibrils do not unite at all inside the cells, and that the
close perinuclear plexu.s which often resend)les a network is in
reality oidy a fcltwork of isolated fibrils.
Thus far, Hethe has studied chiefly the Purkinje cells in the
cerebellum, the ])yraiuidal cells in the cerebral cortex, and the
cells in the ventral horn and in the dorsal horn of the spinal
cord.
TIIK IN'TKKNAI- MDlJIMlOLoCi Y OF NKl'UoN'KS.
\l\\)
Ilia stutcments with rcfjiinl to tlio <il)rils in tlic (Icndritcs
and axoiu'H arc of tlic dt'cpost iiitorcst. Il<' iiiids that not all
the fihrils cnti'rin^' ])y iiu'ans of dcndritos iiit(» the wU body
pass out hy way of the axoiic; on the contrary, they arc just as
likely to pass out of the cell body hy way of another di-ndrite,
and, what is still more interostiiij;, Hethc asserts that he has fol-
lowed librils along one hranoh of a dendrite into another branch
of the same <lcndrite, thus not entering' the nerve cell at all.
A<,niin,in the pyramidal cells of the cerebral cortex he tindsthat
most of the fibrils run lonj^itudimdly throuf^h the ai)ical den-
drites and cell body, l)ut they are evenly distributed to all the
processes at the base — that is to say, to the dendrites there as
well as to the axone. The lateral dendrites of the cell are con-
nected by means of another series of tibrils with one another
and with the axone. Hethe is inclined, therefore, since he re-
gards the tibrils as the conducting substance, to discount the
general opinion that the miture of axones and dendrites is fun-
damentally dilTcrent. As von Lenhossek says, however, in his
critiipu' * of liethe's j)aper, it is by no means proved that the in-
tertil)rillary substance is excluded from the conduction. Von
Lenhossek emphasizes the fact that the marked dilTerences be-
tween theaxojieand the dendrites in (iolgi and Xis.sl ])reparations
can not be without definite physiological significance. If the
fibrils alone conduct, Hcthe's studies would upset entirely the
widespread view concerning the cellulipetal character of den-
dritic conduction. lUit this view" of an exclusive cellulipetal con-
duction for the dendrites and I'xclusivc cellulifugal coiuhu'tion
for the axoiu's, has, in my o])inion (cf. Section \'), always been
founded upon a totally insuiiicient basis of experience, aiul it
would not be surprising should a (MUiduction in both directions
be proved, whether the views of Apathy and Hethe are oi- arc not
in accord witli the facts.
The statement is usually nuide that (lolgi's nu'thod is inap-
plicable to the study of the interior of the nerve (H'IIs. .\s this
volume is going through the press, (iolgi f publishes a di'scrip-
tion of a fine network inside the cell body of the I'urkinje
cells deinonstral)le by a slight modification of the osmo-bichro-
* Neurol. (Viitndl)l., lioipz., IM. xvii (1H!»S). S. 'J44-!)47.
f (lolyi, ('. Sur la stnicturc des celhdo.s ncrveuses. Art'li. ital. de biol.,
Turin, t. xxx (18i»8), iip. (iO-71.
t (
I i..
/
iHMI
^
II
U
140
TIIK N'KUVors SVSTKM.
niiitc |»r(icc(liirc ( l''i;.'. *>*). Siiiiiliir networks have lu'cii sccti
l»y N'cratti, an a;Hsistant of (iol^'i, in the hirj^'c nerve ccIIh wliieli
(i(»l^'i believes j;ive orijjin to the axones of tlie nervus troeh-
learis. (iolgi stutoH that he can Hay
iiofhiiifi: concerniM^' the si^Miilieanee of
the endocolluhir network, hnl he is in-
clined to ])t'liove that his fin(linf,'s thus
fur arc only ii partial manifestation of
finer and more complex structures. He
feels sure, however, that this lu'twork
has nothing' in common with the clas-
sical (leseription of Max Schultze and
his school ; that it has no umilogies with
tlie pictures discernihle in Nissl ])rcj)a-
rations, and that it olfers no correspond-
ence with the interesting results of
Fi(i. 7H. KiKlocciliiliir net- ApiUliv Concerning the lu'rvc cells of
work within i( I'lirkinjc . *,
.■I'll of thf rciciiciiiiiii of invertel)rates.
S'a '■';;:;;;;•::,..':;;;;;':" n^'i'i^ *" ''"I'^tion t,. his studi..s of
iiuMlUiciiiioiiof III., liipid the stainahle part, has also turned his
(tolKi iiictliod. lAfl.r . ' , „ ,
(". o.iiKi, Anil, iiiil. .!(■ attention to the ground mass ot the
l.iol., Turin, t. XXX. 1S...S, j,,„toplasm of nerve cells; tlie full
results of his research have been pub-
lished in an article of nearly one hundred jiages, and beau-
tifully illustrated with lithographic jtlates.* He states that
in sections fixed with alcohol, pierosulphuric acid, or cliromic
acid, it has a distinctly reticular apiiearance. In very thin
sections he can make out granules which are extremely fine,
staining on tlii' limits of microscojiic ])ercej)til)ility. No tibrilhe
could be observed except at the wedge of origin of the axone
and in the more cytodistal portions of the dendrites, in which
tlie tigroid masses cease to appear. Here he coi;hl make out,
stained bright red in erythrosiii, a tine longitudinal striation
along with an arrangement of extremely fine granules in rows
and i)ressed together, as it were, so as to give the appear-
ance of fibrilbe. Held believed at first that he had before
him the librils of Max Schultze. On using dilute solutions of
* irold. H, Heitrttfjc zur Structur der Nervcnzi'ilon nnd ilwcr Fortsiitze.
Zweite Al)han(lliiiij,'. Arc-h. f. Aiiiit. ii. I'liysiul., Anal. Abtli., Lcipz. (1^97),
II. iii n. iv, S. i204-2!)4.
if)
* Kamuii y Cajiil {op. cil.) lias rocuiitly supported vigorously llii' doclriiM!
of ii lioiu'ycoiiili stvuclurc for the imstainiiblp sulistancc.
f Fisclii'r, A. Zui' Krilik dcr l''i.\irun<;siiR'tlio(l(Mi uiid dor (iranula.
Aiiat. An/.., .loiia, i?d. ix (1894), S. (STS-tWO; also Ncuo Hcitrii-ic zur Krilik
dcr Fixirun,<,'siiiftliod('ii. Anal. Anz., Jena, Bd. x (18!)4-'9.')), S. TOft-TTT.
:{ Oalootti, (i. rdicr die (ii-aiiulatioii in den Zi'lU'ii. Internal. Monut-
schr. f. Anat. n. Physiol., Ivip/., 15d. xii (18!^)), S. 440; 4G1.
■ 1,
!/:i
TIIK INTKHN'AL M()I{IMI()Ii()(!Y OK XKl'lJONKS.
n
!■."''
(•Iinimi(! iH'id, however, imd of uininoiiiuin hieliroiniitc, lie tliil
not ohtiiiii til)rils, Itiit in the thiniioHt HoctioiiH hiiw (tistinet
I'oiiMilike stnietiire.s ; espeeiiilly on .stnininjf witli iron-hienia-
toxvliii without iiny siihse(|iieiit ditVerciitintioii, he (d»laine»l
honeyeonib i)ictiii"es wliieii correspond entirely to tlie pietnres
and descriptions of Hiitschli. Ilehl, in opposition to Mux
Schultze imd II. Scdiiiltze iinionj^ the older hist<»loj;ists, iind I'Meiii-
liiiiif?, Heiuhi, and Doj^iel of the present time, is inelineil to ji(!-
(H'pt Miitseiili's view thiit tlie (ihrilhe of the ohler ol>servations
correspond to lonj^it iidinal layers of honeyeoinl) cells which lie
close over one another ; Held will not ^'ra lit, however, that the
nerve cell actually possesses a honeyconilt structure, since he
l)elieves that lixino' a^^ents with which it appears exercise u
marked vaciiolizinj; iiillueiicc upon liviufjf nerve-cell proto-
jilasni.* lie has worked with an extensive seriis of fixing re-
ji<;ents, ineludinjj:, in addition to the weak bichromate solu-
tions used by Schultze, the lixiiif? fluids which Hiitschli has
emjiloyed, and also the niajority of the tliiids now j^enerally
ii])plied in the teehiii(pie of modern cytology. The results
he has ol)tained lead him to the view that the various dilTer-
enees met witli in the (h^scriptioiis of iiivesti<,'ators in dilTerent
laboratories are in lar<,'e part due to the fixinii; factor. Nor
does Held aeeejit Rosin's view that of the two main sub-
stances in nerve cells one is acidophile and the other baso-
pliile. Uelyiiifj rather iiiton the recent researches of A.
Fischer,! and of the Italian investij^ator (ialeotti,;j; he has
come to the conelnsion that the so-called elective stains de-
pend more ui)on physical factors than ujion purely cheiiiieal
differences. In the first jilace, closely arran<je(l <,M-anules absorl*
coloring matters much more intensely and hold them longer
when subjected to diffi'rentiatiiig flui<ls than loosely l)uilt
parts; and secondly, the "covering power" {Dcclikrdfl) of
dyes has to be considered, since through covering-over con-
stituents, stainings which are really only apparent can result.
ii
m
"M
'i.l
1
11:
TIIK NlMIVOrS SYSTKM.
i
'0
i||i'
il
Mel livli'tic liluc, lor i'\iiiii|tl(', is Isiiown lo luivf a very liiijli
covcriiii,' power.
\'aii (iicson, van ( icluichti'ii, IJaiiioii y Cajal, aiul otlicrs
assert tlic cxistciift' of a (lisliiict rcliciiliim wliicli cxti'iids
tlironnlioiil the cell body and all its |»n)c('sscs (dendrites and
axones). There may l)(', they tinnk, a dilTerence heiween tlie
relieulnm in I he (h'ntiriles and that in the a.xoiu's. Killin<f np
the intersliees in tiie retienlnni and hatliini:: it is liie softer and
more llnid part oi" tlu' nervi' e;ll, the cell sap. \ an (iieson re-
ports some interestinir experiments made on the nerve cells of
the coekroaidi, in whieh he has found it jtossiliie to Sfpiei'ze ont,
the e<'ll sap, leaviny' liehind only the cytoret icnhini. lie looks
upon the eytoretienlnm as the contractile ])art of the nerv(*
cell ])rotoplasm, and lielieves that, extending: into the den-
di'ites, it may enttr into the formation of
the irt'inmules present on many of these,
processes.
Tlie views which have heen held re-
!;ardin<f the strnctiire of tlie axone are as
diverixent as those conceniinf; tlie striie-
tnre of the mtn-stjiinable portion (d' the
nerve cell <i('nerally. The idea that it
jiossesses a lil)rillary strnctnre, sn,<j:,ij:ested
hy Kemak and so strongly uri^ed hy .Max
Schnltze and l-'r. S(diultze, Knfj^elmann
and von Kidliker, reci'ivcd important eon-
(Ai'i.rSrlii.il'.nl.ck.'i-. ) jirniatioii in the reseandies of Scduetl'er-
'l'llcri.n'(il':l\iilM' lililils • i • i ■ , ,. , ■ ,
is siinuim.lcil iiv il [ir- ticcker.^ I Ins liistoh)jfist lonnd, in the
;;,•';;,:;;' ,w',^;;,.i;;!',:""" iH''-'"*'''"y f""^'' "^"'-v' ti'-^-sof petron.yzon,
what he rejjards as iindonhted evidence
of the existence of tihrils inside the axone {Vl^i. T!')- 'I'l'*^
axones of the nerve cells of this animal consist, accordinjj^
to S(duetTi'rdeid\er, of two esseidial constituents, the axone
tihrils anil a homogeiieons substance, the axoplasm or neuro-
plasm. In petromyzon the axone tihrils tend to run in the
ct'ntre of the axone, a laryc area at the periphery of the
axone heiiiiX entirely f''ee from librils. This peripheral zone
l''l(i. Til. — ('ri)ss scclioiis (if
Iwc) axiiiics iViPiii llic
iiiiviis li'ini'iiiinus ni'
I'riidiiijr-'iii lliiriiililis.
Ill
U
* ScIiiotTonlcelicr. P.. iii ScliiofTcnIcckcr u. Kosscl. riowcliclcliri' mit 1)0-
sdiidcriT Iii'riiclvsiilitij,'iinjj dcs iin'iisfiiiielieii Kilr|iors., \U\, ij, IJi'iiscliwi;.
(ISDI). S. -JOO.
"UK INTKUNAL M()1{IMI(»I,< >i; S ol' NKl i;()Ni;s. l.|.;>
consists entirely of iieiiropliisiii, uliicli also extemls in iiMKin;,'
the lihrils ot' the ccnti';!! eore. 'I'lie lilirillary appearanee is
easy t(» make out in the axones of ey( lostonies and niollnses
(Riiwitz).
Siihseipienl researelies upon liii^lier forms make it not im-
prol)al)K> tliat. a simihir structure hohls in th(>ni. It would
seem, however, that, in inedidlated nerve lihres the axoiic lihrils
are moi'c evenly distrihuted throughout the whole axone, tlu^
peripheral layer of pure neuroplasm l)einjf ahsent alto^nM her or
reduced to a very thin superlicial lilui ( l-'ii,'. SO). 'I'here are
mm
Kk;. HO. — LiiiiKihiiliiinl mikI Iransvcrsf section of in.Mliilliitrd nerve li'nres I'roni
iIm' seiiiiie nerve ol' llie IVou ( osinie ill-id :inil aeiil I'lielisiue ). (Alter Itieder-
niann. ) 'The lon;;iln(lMi;il section sliows one node of itiinviei' iiml two of
I-iUilerniMnn's sej;Mienl;ilions. The lilirilliiry striicliire of the axone is sliowii
in liotli lou^' and eioss section.
lujiiiy histol(><j;ists, however, who refuse to helieve in the exist-
ence of iictual lihrMs inside the axones of higher animtils. Tlio
doctrine of tiie lihrillaVy nature of the jixoiie and tinstainahle
portion of the protophism ^)\' the nerve cell has recently r'-ceived
support from the stuilies (d' l>u,t,f;iro '" tiiid of Levi.f 'I'he former
too, in his stmlies of the nervi' cell under patholo<j;ic!il condi-
tions — for exiimplc, tifter poisonin>^ with lead iiinl jirsenic —
liiuls that the lihrils mav hccome verv distinct inside the nerve
eells.t
Ileld's description of his liiidiii!j;s in the tixis cylindci's of
nerve cells is leiiiithv an.; detailed. With a liirtre series of
1
i
n
* liiitraro, I']. Sill valoi'e rispelliva ilelle |iai'le erdinalica e della airo-
iiialica n(>l citoiijasiiia ilelle eelliile iierviise. IJiv. ili |iatol. iierv., {''irciize,
vol. i (IS!l(i). pp. l-II.
f Ijevi. (J. Sii aleiiiii' pari ieolarila ill si nitl lira del iiiii 'ei. i celluli!
niTvosn. Itiv. ill piclol. iierv., t'lreiize, vol. i (IS!((i). pp. Ill I lit.
X Iiiinarii, I'l. Siille allera/.ioiii ileeli eleineiili iiervnsi in't^li .iiVeli'im-
ineiiti per afseiiico e ])('r piiiniiio. Uiv.ili palul. iu>rv., Firen/.c, vol. ii (18!)T),
pp. JiMM.
J
1 i
'1 I
i:
ifM
i I
il
if ll
144
TIIIi: NERVOUS SVSTKM.
itit;.-',-. ^'
.I'j
fixing I'Oiifi^ents, amonir wliicli van (ieliiu'liten'a niixHirc (CO
parts alcohol absol., 'M) puits clilorot'orm, and 10 parts acid.
acet. glac.) yielded the most
constant and satisfactory re-
sults, Held conchides that there
can be no fibrillary structure
of the axis cyliiuler if by the
term fibrils one uiulerstands
isolated threads running near
one another. Instead of these,
Held finds always a network-
like ap}»earance which in his
„, . . ,. T . , 1 thinnest sections is seen to be
Fkj. 81. — Axis cylinaor m loiifr iiiid
<T()ss section I'nmi ;isi)iniil t;iuij,'li(m extraordinarily delicate aiul
in till' lmnli;ir icjriiin <il' an iidiilt , i i " t i.i • i
(loK. (Alter Held. Aivli. I. Anat.u. lollg-mcslied. ill tlllS UlCsh-
riiysiol.. Anat. Ai.tl. IS!.-, 11. w n [^ ijjj.]j jj^. dosiguates the
4, Tat. x, I'lj;. Tt.) Siibliinate and ' °
acetone fixation ; parailiii section axosjiongium, are to be seen
1.,") microns tliick. Stainiiif; witli ^ . -, , ,
eiythi-osin inetiiylene-idue. Neuio- Certain grauuies somcwliat va-
sonies and axosiioiifxiinu are clearly ^.j,,!,]^, -j^ gj though alwayS
visible. . ' . •'
very minute, which lie gener-
ally at the nodal points of the network, though sometimes
iu the spaces wjthiu the walls of the vacuole-like cavities.
.. i' **■■';: •:i
'^■■<^..*''-^^
" '• f>^v-:i^^-- ^-V-" •••■•/ ••.'A;:: ^**: V
\^ . a,".. » -j^.-'^_: '■::', .-. v. .• '•.; > !•■'/, ;'. '• V • . . '.'■ ■ '■7:.'.' ;*•;•
'■■■ ' i. *aJh« ■'•. * ■ •" .• •• ' *' ' .* * •* ^ • » •*' *••'■• * • *'•. ' .>* !•
V, .'.•;• ..■;...•.-.,'• •,■.,«.",/•■•:••• •" - ...»"'
Sheath.
Nuclei of celts of sheath.
Via. 82.— Axoiie liillock of a siiiiinl (laturlion cell oI'IIumIi,};. ( .Vl'ter Held, .\rcli.
f. Anat. n. Physiol., .\nat. Alitli., ISil", Taf. n, Fi^. 4.) fixation with siih-
limate-acetone : parallin section l.."> microns tliuk ; slainint; with er.vtlirosin
ineth.vleiie-hlue. The Nissl hodies, the neurosoines, the c.vtospoiiKinm and
the axospouKinin aic visilile. '{'lie arrangement of the neiirosomes in rows
and the lon^titndinal mesh t'ormatioii of the axospoiifiinni is parliciilarl.v dis-
tinct. The alteration in the appearance of tlie meshwork where the axone
hillock fjoes over into the hody of the cell is distinctly shown.
These granules — Held calls them neurosomes — are not, he
states, reguliirly distril)uted either in longitudintil or cross
sections of tin axone (Fig. SI). The neurosomes appear to
Tin-; IXTKRNAI. MORPHOLOGY OF NEURONES.
145
liiivo boon observed before by l?utsclili, Altmaini, aiul others,
tlioufj;h l)Ut little iittontiou seetiis to have been paid to tliein.
Ill tlie axone hillock the iieurosomes present coiistautly a
radially ('onverijiii<:f jiroupiiig (l''ij,^ ^'-i)- 'I'hey sei'in to be
extraordinarily numerous in the terminals of many axones,
for exaini)le, the mossy and elimbintf iibres of the <'erebellar
cortex, in those ending on the ventral horn cells (Fig. >>'■>)
and in the terminals of the axones of the i)eripheral olfac-
tory neurones. Inasmuch as in the ground substance of
the dendrites and cell bodies of the neurones the iieuro-
somes are much less nunu'rous, a ready method of distin-
guishing the ])rotoplasin of ti-rminal ax(»nes in cytological
jireparations from that of other ])ortions of neurones which
lie in direct contact (or concrescence) with one another is
afforded ua*
Montgomery,} in ini able pajjer, has denied the existence of
fibrillary structures in nerve cells. lie supports the doctrine
according to which hyaloplasm and spongioplasm are the two
])rinei))al constituents of protoplasm.
Flemming J emphasizes again that lie has admitted that his
fibrils may be i 'inected by obli(jue Iibres running from one to
another. He niiantains that in any case the longitudinal fibril-
lation is always much more pronounced, and that it can ofti'ii
be seen when nothing in the way of a transverse fibrillation is
discernible.
\'ai'ious attem])ts have l)een made to connect the function
of conduction through the })rotoplasm of the nerve cell with
one or another of its finer histological constituents. Apathy *
es[)ecially is convinced that his "neurofibrils" reiireseiit the
essential anatomical basis for conduction, ami he constantly re-
fers to these fibrilhv as the conducting element {this Ici/nu/e
l\lniinil) in the nervous system. Betlie shares this view.
* Held hclii'vos tliat the lilirils of some Investigators — for example, tliose
of Dofjiel — are in reality identical with rows of neurosomes. He even hints
that some of Flcinmiiiij's filirils n'lu'esciit hands of neurosomes; olhcr filn'ils
descriiied \i\ l-'leniminf? are. Held l)eli(>vcs, heams of the eytosponj,'iuni.
f Montfjoniery, T. H. Studios on the Elements of the Central Nervous
System of the Heteronemertini. .1, Morphol., liosl., vol. xiii (18!)7), pp.
3S 1-444.
^Flemming, W. .Article Zelle in Merkel-Honnet's Ergetjiiisse der Anal,
u. Entwiekehingsgeseh.. Md. vi for IMJIG, Wiesbaden (1H!)T). S. '.MM 11.
« ()l>. cit.
11
11 /<
1v
II
U'
( ^
^*->.. .
TIIK INTKHNAL MoKIMlOLOdV (>!•' NKrUONES.
14'
It wiis and is still Ticydi^'s* opinion tliiit tlio " liyiiloplasni "
of i\n' nerve cell whidi fills up llu' (lu'slu's of tlie spoii^'ioplasm
represents the eondm-tini,' suhstanee, a view wliieli, in the main,
was supported ])y Naiisen, though the Arctic explorer assumed
that the hyaloplasm is arranjjed, hoth in the axis cylijider and
in the body of the ni'rve cell, in the form of "primitive
tubules."
Other invi'stifjators assume that it is the spon<;ioplasin
which is active as the conductinj^ a<;i'nt — an o])inion which
would accord well with the ideas of MacCallum f with regard to
the cojitractility of muscle.
The liypothes(^s of Leydig and Nansen have l)een vigorously
opp()S(Hl l)y Hiitschli and by IMlueger. Miitschli himself is
strongly of the opinion that tiie framework substance of the
nerve-eell protoplasm, his Wiiijciit/cril.s/, must be considered to
be the histo'ogical substratum of nervous conduction, since it
alone extends continuously tiirinigh the axis cylinder, and is
accordingly the only structure in a position to underlie the
])heJU)men()n referred to. He brings forward in favor of his
view the statement of I'llueger that ni'rve iibres can hi! excited
only by means of currents tlirected longitudinally, not by cur-
rents directed transversely.
Held argues that, in view of the possibility that the so-called
foam structure may be an artefact, due to the tixation of the
pi'oto})lasm, it is premature to assume that the meshwork
■sei n in fixed specimens is necessarily the conducting suhstani-e.
Kven if it does correspond to the structure of living })rotoplastn,
it would he diflicult to deny for the delicate transverse con-
necting bands the possibility of a function freely granted to tlie
longitudinally running c(»arser beams of the meshwork. Held is
inclined to look upon the ground substance of the protojdasm,
'^s• a //'//»/(", as uceoiinting for the function of the propagation of
stimuli, though he does not deny the possibility of the tempo-
rary existence of sei^tions of this better or wors;' adapted for tlu^
function de})endent upon alterations in vital chemical constitu-
tion.
As a matter of fact, /rr i/<i mil li'iioii' the exact histological
♦liCydif:, F. Dor rcizieiloiKk' Tlifil <lfs Ncrvciifjcwobi's. Arch. f. Aiiat,
u. I'liysidl.. Aimt. Alitii.. Lcipz. (ISOT), S. 4;n-4(i4.
f MacCiilliiin. .(. 15. On tin- llistolej^'y :ni<i IIisl<i;;i'iiisis of tlic iiiart,
Musclf evil. Aii.ii. All/.. .Idiit. M«l. xiii (IS!t7), S. (i(liM)',»((.
1
m
n
M
''stni
.1 ; .
148
THE NERVOUS SYSTEJI.
Ill
'
i
^:.^^:r.r;^^?safA.^
FlO. 84.— ('('iitrnsonu' iiiid iittiMctioii
siilicrc inside n s|iiiinl ^'un^rlioii <
iiK'clianisin in tlic |)r()t()i)l!isiii of (lie lUMiroiio luidorlyinf? tlio
coiidiu'tioii of wliiit \vt' cull lUTVo stiimili, and wc should l)t'
willing to confess it. If we form iiypothcses concerning it, Ic^t
us label them distinctly us such,
und take care not to grow,
through familiarity with them,
into the idea that our hypoth-
eses are uctuully proved facts.
\'on Lenliossek* hus brought
tlie nerve cell into still closer
ugreement with the generul
cellulur structure. He hus been
uble to demonstrute within cer-
tain of the spinal ganglion cells
(Fig. M4) of the frog the pres-
ence of a delinite centrosonie
and uttruction sphere {C'enfru-
i'l'j xph(i)'t'). Biihler \ subsequent-
ofthrfioj;. (Fnmi Wilson, all...- v.m | ,ie„(.,.ibed u ccntrosome und
Lcnhipssck. ) I ln' allrartion si)1k'1V •'
is seen sitnatcil in tiic cytiipiiism tint uttructioii sphere together with
fill' fnini the nnclcus. Inside tiie i • i • ^• l- • i
attraction si.heiv is siniwn tile single archiplusilUC rudlutlOUS in the
crntroson.e, wiiicl. .••mtaius sevi-nil ^^ (.g|| ^f ^|^p ^^ -^^ f ^;^
centnok's.
lizard, while Dehler J hus dem-
onstruted pole corpuscles and attraction spheres in the sympa-
thetic cells of the frog, l^p to the present time these struc-
tures, to which very importunt functions have l)een attributed
by many cytologists, have not been demonstrated in the nerve
cells of mammals, with a single exception to be mentioned im-
mediately, l)ut it is not improbable that the evidence for their
existence in these also will soon be forthcoming. I find in the
second portion of Kolliker's text-book, which has recently been
publi.died, that he hus found centrosonie and attraction sphere
in a giant pyramidal cell of the jiosterior central gyrus of a
* von Lcnho.'^SL'k. ^I. Ceiitrosom unil Sphiire in dcii Sijinalpanfilionzcllen
des Froselie.s. Areli. f. mikr. Anat.. IJonn (l.s!t5). I'.d. xlvi. S. 34o-;?(;!l.
f niilder, A. ProtopUisina-Structur in Vorderhirn/oUcn der Kidochsc.
Verhimdl. d. pliys.-nuHl. (ieseilscli. zu Wiirzh.. n. F., Hd. xxix (IS!).")). S. 20!)-
253.
i Dehlor. A. Heilrai; zui Konntnis vom feincron Rnu der synipatliisclicn
Ganfjlienzi'lle des Frosclics. Aroli. f. mikr. Anat., Honn, Bd. xlvi (18!t5), S.
T24-7;5».
TIIH IXTHIJNAI. MOUIMlOLOdY OF NEUUOXKS.
U9
thirty-yi'iir-old man.* SchatTcr f lias also lately (leseribed ccii-
trosoiiR's in tlu' f^anjxlion colls of cyclostonios, McCluiv I in
molluscs, and Ilamakcr* in Nereis.
Mar<:arct Lewis || has described centrosome and sphere with
radiating lihrils in certain {jjiant nerve cells of a new annelid
(related to ('IjimviivUd fiirqudta). She does not think, however,
that the evidence yet sutHces to prove that the central cor-
puscle and sphere of nerve cells and the centrosome and s])here
of divi(lin;j^ cells are e(|uivalent structures.
The siifnificance for the cell economy of the centrosome and
attraction sphere has been the subject of considerable contro-
versial literature. While some histologists would make the
ceutrosonu' the arch power, tlie seat of <jovernment, as it were,
of the cell, and would <,nve it }»recedence even over the nucleus,
others, with Watase, look upon centrosomes merely as moditied
cytomicrosomes.
It must be confessed that in view of what we know of the
relation of the centrosome to the phenonu'iia of nutosis a na'soH
(fr/rc for this body within the nerve cell is at first thou<,dit ditti-
cult to find. It might be assumed, of course, that it has re-
mained over from the last cell division. If the old view were
correct, that gaiifjlion cells fully formed never divide, little
reason could, perhaps, be found for the persistence of the cen-
trosome. The studies undertaken of late make it necessary,
however, to hesitate before denyinjf the possibility of division
of adult nei've cells by karyokinesis ; in such cells the centrosome
could be of its ordinary sifrnificauce. Thei'c is no fjround as
yet, however, for the statement that the centrosome possesses
*Iv()llikL'r, A. Ilaiiillmcli (liT (icwchclchri' dcs Monsclu'ii. Hd. ii. Lcipz.
(i;W). s. HI -J.
f SelmlTcr, .F. rdicr cincii lUMieii IJol'iinil voii ('(Mitrosoiiicii in <iaii,nlipii-
uiul KiiorpclzoUcii. Sit/iuijjsb. d. k. Akail. d. Wissenscli.. Math.-iiaturw. CI.
lid. cv, Wicn (ISiKi). S. 21-2H.
if .Mi'Cliuv. (_'. F. W. On thi> I'rcscncL' of ("cntrosonics and Attraction
•Spheres in the (laiif^iion Cells of ffi/ix PovKi/iti. with Hemarlv.s upon the
Structure of the Cell Body. Princeton Coll. I5ullitin, vol. viii (I80ti), No. 2,
pp. :'.S-4I.
* llanuiker. .1. 1. The Nervous System of Xciri.t rZ/v/f-s' Sars. A Study
in ('oniparalive Neiiroloj;y. Hull, of the Mas. of Coinp. Zool. at Ilarvanl
Coll.. vol. xxxii (IHi)M). No. ti, pp. 89-i;.M.
II Ijewis. Mar^faret. CeIlt^o^i<)lne and Sphere in Certain of tlu^ Nerve
Cells of an Invertebrate. Anat. An/.. .Tena. l?d. xii (1890). S. :291-2!»y.
i
1*
: i
;
J '
■■ i.
I
i:.(i
TlIK NKlJVOl'S SVSTKM.
IK) riiiK'tioiis other tliiiii those eoiieenied in tlie division of
the cell; indeed, it niiiy have to do in niiiny instiinees with
motor activities of cells indei)endent of thosi' involved in
mitosis. Itesides, the existence of centrosome and sphere in
niiiiiy cells, which are not dividiiifj and whicdi exhihit no deti-
nite phenomena of motility, make it likely that these strne-
tiires are of value to the cell in ways other tlian tiiose
hitherto su^<festetl. The centrosome in nerve cells, as in other
cells of the hody, may ai)pear solid or it may show numerous
centrioles.
In closini; this chapter reference may also be made to the
pe<'uliar and delicate investment of the cell bodies and dendrites
of neurone.- tirst desoril)ed by (iol<ri * in his article on the spinal
I'k;. S,"). -N'ci'vc rcll sliiiwiiii,' ri'liciihir iiivi'sliufiit. AftiT ('. (Iiils.'i. Afcli. itat.
lie liinl.. 'I'miii. I. \\.\. IS! In. p. 11:^. Tlic cill i> tVinii ihr vciiifnl horn nC llic
siiiiial conl 111' a ral.
cord in ISS-?, publisheil in the Kncyclo])cdie mcdicale. Accord-
ing to the Italian ohserver this investment [iresents various a])-
})earances; sometimes it is a reticular structure; sometimes it
forms a continuous homoufencous layer; sometimes it apjjcars
* ("f. Jilso (idliri. ('. Intonio air orij^'ino del (niarto iicrvo ccrt'liralc c ili
una (lucslidiii' istn-fisitildf^iua clie a qiit'Slo Mrudiiioiild si colleira. Kt'iidic. d.
R. Accad. d. l-iiicci (18!)8), ii. Froiu-h 'riviiisl. in Aicli. ital. di> liiol.. 'I'uriii.
t. xix (ISn;!), pp. 454—174. Also. Sur la striirturi' dcs oi'llulfs iiitvcusi's.
Aruli. ital. de biol., Turin, t. xxx (IWW). pp. «0-Tl.
r
m^^'
Fl(i. Sf).— rcrici'ltilliir iict\V(i;ks hclicvid liy Held In lie Idinicii l).v llic triiiiiniils
111' MNoiifs. (ii)lni iifi|i;iriiti<ins I'idiii a cat twciilv davs nld. Sect inns 70 /m.
tliirk. (After II. Iltld. Airli. I'. Aiiat. ii. I'liysinL, Lcipz.. 1S!»7. Aiiat.
Alitli., Siipi)). lid.. Tal'. xiv. Kins. .">. 7. and S.I .\'. (VII with nctwmk IVnni
iiiiclciis iicrvi ciMJilfaiis vciilialis. Tlic iH'riccllular network siindiinds tlie
wiiole cell and a dendrite passiim upward. The lilire n eniicspnnds to one
id' the thii-ki'ne(l lilires (if the N, e(ieiih'a' desci-ihed )py li'anion ,v ( 'ajal and
II(dd. lieyond llie lliiekened spot lihrils j.'(i to Join llie i;iiieial piTiceliniar
network. 1>. I'arl of tlie iielwoi'k ai'onnd a cell in llie nnileiis nervi vestili-
nlaiis lateralis (Deitiisi. Held lielieves that the thicUeiiinirs in the nct-
wmk may ciirrespond to the a^iireijations of nemusoines which stain in inm-
Incniatiixylin preparations. ". '<, c. (/. c, ,/', axones wliich help to t'orni the
network. ('. Part of the network around a cell of the nucleus mrvi coidi-
learis ventralis: the anastonnises i>\' the coarser suhdivisioiis ol' the lihres
((and /( ind the larger swelliiifis of the threads of the network are dearly
visible.
t
!H
i
p
i:>'2
TIIK N Kit vol's SYSTKM.
as ii niosiiic of (Icliciitc scales; not iiifr('(|ii('tifly it presents
iiiarkiiij^s wliicli |»rol)al)ly <'<»rres|t()M(l to tlu' imprints of nerve
lihres or other fibres inipin^'inj,' on tlie nerve cell. Tiie retien-
lar variety seems to he most common; it may invest the wliole
of tlie coil body and bo followed ont n|)un the brancliinfj; den-
j5«»-r~'
Vui
A H
. S7. Nctwcirksiilioiit )i<'rikiir.vipii :ui<l cl< iidritrs (Icnicnistrahlc liy tlie inctluid
ol' iicllu'. i.M'tcr V. Nissl. Miiiicliiii. iiicd. Wcliiisclir., !!il. xlv. ls!ts, S. W.H,
Via. 1 II. 2.1 \. Nerve cell I'nirii the muleiis lieiitattis of ii dtifj. 15. Nerve
It'll iViiiii Deilers's llllelells (it'il ndiliit.
drites as far as the subdivisions of the second and third order;
upon these l)rajiches, however, it loses its reticular nature in
order to assuiiu' the character of a homof^eneons layer, (iol^i's
illustrative figure is rejjroduced as i''i<;. 85. As to the exact
nature of tlu' substance concerned, (iolj^i s])eaks \'a<;uely, su<;-
frestiji<; that it may be of the mitnre of neuro-keratin, thou<,di
liis digestion ex})eriments with trypsin and gastric juice are not
■t'l :
TIIK INTKKNAL MolUMlOl.OOV <»F N'Kl'UONKS.
i:.;{
dooisivi'. Similiir itivestmoiits luivu bi-i-u doscribi'd by Lugiiru *
iiiid by Murtiiiotti.t
Hold J dt>s('ril)»'S and pictures (Kij;. S(i) pericellular aiul
pcridcudritic iictwdrks dcuionstrablc by (ioi^q's luctliod, wliidi
he believes are t'oruuMl by auastouutsis of the subdivisious of the
Hue axones teruiiiiatiuff there. Ill wiuit relation these stand, if
any, to the pericellular investnieiwt of (iol<,d, further work must
deterndne. liethe by his method also linds pericellular net-
works formini; " stockinj^s," as it were, drawn over the peri-
karyon and the dendrites. These are illustrated in Fig. 87.
* liUpUMj, H. Sulla si rutturudi'i iiucluo ili'iitiito del (■crvillcllo iiciruomo
JlDuitorc Zool.. Firt'ii/i', vol. vi (1H!I.")).
f M;u'liiiiilli. ('. Sii iilciini' ptu'licolariiri ddli' (•cllulc iicrvosc <irl mi-
(l(illi) spiiiiilu iiu'sse ill ovidi'iiza ('"lla ivazioiie iicra del Uulj^i. (iiur. d. U.
Acciid. d. iiumI. d. Torinii. im. lix (lS!)(i). Fri'iudi 'rrunsl. in .Vrcli. ital. dt;
l)i(il., Turin, t. xxvii (1,h<)T). pj.. 25:!. :i.">4.
X llidd, 11. Mcilraj^i' zur Structur dcr NiTviMizcllcii uiid ilircr Fortsiltzc
Dritic Ahhaudlunj,'. Arch. 1'. Anal. u. I'liysiol., Lcipz. (1K!»T). Anat. AMIi.,
Suppl. lid., S. 27:2-aia.
A
11
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IMAGE EVALUATION
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i
CHAPTER XIV.
SUMMARY OF <)V \l K NOWLIMXi K II'OX TIIi: IXTKUXAL
sTiaxTriU'; of xei'roxks.
Coiitlicting vii'ws rc^janlinjj cell orgaiiizatidii in j^ciicral — Siiiiiiiiai-v of tlic
oxistinjf state of kiiowledgt' i'(Miceriiiiig the internal !<tnu'ture of neu-
rones.
It tnu.st be obvious tliiit tlic idea ontertiiiiiod 1)y any given
invest ii^'utor regiiiMling tl)e iiltiiiiate slructufc of the nerve cells
is oolori'd (l('0])ly by the o])i)i!(>n which he holds as to the nature
and strticltire of i)rot()plasiii in general. Until some agfei'inent
has been arrived at iunong cytologists regarding the latter,
we can scarcely hope for a nnanimity of opinion concerning the
former. It is not necessary here to discuss in detail tbc diverse
theories bearing upon the . nature of protoplasi>i. A whole
series of them — the micellar theory of Xiigeli, the network
theory of Frominann, the thread-framework theory of Flcm-
ming, the foam or honeycomb theory of Hiitschli, the })lasome
theory of Wicsener, the bioblast theory of .Mtmann. its well as
many others — have been fully outlined and compared in several
places.* The majority of histologists and zoologists can not
conceive of the cell is the elementary organism of the body, but
postulate the existence of units or elementary oriianisms tniich
smaller than cells. f Those who are interested iii developmental
* Cf. Ilertwig, (). Die Zelle und die (iewelie. .lenii. isici ; ("arnoy, J. R.,
and II. Ijehrun. \iH eylodiurese de I'd'uf. \m vrsicule gerniinative el los
globules polaires cliez les hatraeicns. Cellule. Lierre and Louvain, t. xii
(l'S!)7), pp. IS'.)-'^!!,") ; and especially for a lirief liiit tliorougli critical I'evicw
eunsull Waldeyer. W. Die neutM'en Ansicliten iilicrden Hau und das Wesen
der Zelle, Deutsche med. Wchnsclir.. licipz. u. Herl. (IS!).')), xxi. 70;i; 727;
T<i4 ; 770: HOO; 84(1, h'or an admirable review of the modern literature con-
cerinng tiie liner structure of the cell, in which many original ohservalioiis
are included, the book of E. 15. Wilson, which has recently been published,
entitled The ("ell in Development and inheritanee, \. Y. (lHi)7), Hvo, is
heartily reconuneiided
f The reader who interests himself in this side of cyt(jlogy is referred to
1o4
!
THE INTERNAL MORPHOLOGY OF XKUnoNES.
155
relations and their bearing upon licnMlity have perliaps <;one
furthest in this direction. Koux, an apostle of the niechanieal
theorii's of developjuent, not oidy assunu'S the existence of ele-
mentary orpmisnis within the cell, l)Ut classifies them into a
number of varieties corresponding to tlieir main characteristics —
for exami)le, into " idioi)lassonten," " isoplasscmten," "automeri-
zonden," " autokineonten " ; and those who are familiar with
tlu' writings of August Weismann will remember tiie enormous
significance which is attached to his " liiopiiorcs," " determi-
nants," and " ids."
In fine, the status of our knowledge about the intermd struc-
ture of the }»rotoplasm of nerve cells may perhaps l)e sujumcd
up as follows : A neurone is nuule up, like all other cells, of
nucleus and protoplasm. In the latter a centrosome and a so-
called attraction sphere are present ; at least, they have been
demonstrated in a certain nund)er of nerve cells. The jirotojda^;-
niic portion of tiu' cell can be roughly dividiMl into a ]ieri])hcral
ex()i)lasmic portion and a central endoplasmic portion. In neu-
rones, as in muscle cells, though less distinct in the former than
in the latter, there is a tendency to a fibi-illary structure, tiie
fibrillation being more j)ronounced in the jjeriitheral exo]»lasmic
portion of both nerve and miiscU' cells thiiii in tiu' eiidophismic
portion of the protoplajui. In both exoi>lasm and en(h)plasm
there can be made out, in tissues which have been fixe(l, a more
or less homogeneous ground substance in whicli are dej)osited
larger and smaller masses of a granular nature. The grouml
snl)stance corresponds, in tissues fixed witli alcohol and stainecj
l)y the methods of Xissl and Held, to the " unstaiiuible sid)-
stance " of Nissl, and the nuisses of granules to the "'stiiinable
substance " of Xissl and the i)igment.
The " stainable substance " of Nissl (the tigroid substance
of von Lenhossek) in tissues of healthy animals of tlie same age
/I
-rTt
y
I lie l'<il 111 will ij : (iraf. A.. The Imlividtiiility of tlic ('ell, wi.li mi Introiliictiou
(III till' Apijlicatidii oi' Cellular Hinlouy to llic i'rolilciiis of I*alliol()i,'y liy V>r.
Van Gioson. State Hosji. liull.. I'tira (1S!I7), ii. pp. KW-ISS; SlTilir, A.,
Letzte Lchenseinheiten uiul ilir X'erhaiul /u einem Iveinipiasiiiii Ijoipzig u.
Wieii (1S!(7); Meyer, A., I>ie I'JMsiiiaverhiiiiliiiiijeii uml die Mi'inliraiieii voii
Volvox glolial or, aureus uud terlius, luit Uiieksiclil aiif die tierisclieii Zelleii,
Bot. Ztfr, Lcipz., I5d. liv (1800), No. 11-12: aii.l von KTilliktr, A.. Die Eiior-
ffiden von v. Sachs iin Lielite der Gi'welielelire der 'riii(>re. N'erliaiidl. d,
phys.-med. Gesellseli. zu Wiirzli. ii. F.. I'.il. xxxi (lK!)r), S. 1-21.
i
ir)(i
THE NERVOUS SYSTEM.
II t
iiiul species, killed in ;i prescribed maimer and sul)mitted to
the same method ol" tixinir and staiiiiiij^, is toierahly constant
in a])pearancc and arrangement in the cell bodies and den-
drites of the same groujjs of nerve cells, a fact of extreme
im[)ortance for nerve anatomy and pathology. The axones, as
well as their hillocks of origin in the l)odies of the nerve cells,
appear to be entirely devoid of the " stainable substance " of
Jsissl.
Whether the stainable substances represent bodies precipi-
tated from solution through the action of reagents or bodies
pre-existent thougl) invisible, first brought into \'ii'\v through
the action of llxing or staining reagi'Uts in the hai'dcncd tissues,
in cither case they appear to yield the chemical tests character-
istic of the group of nucleo-albumins. Whether the staining
reaction characteristic of the staiiud)lc substance depends upon
chemical relations or upon purely i)hysical conditions must, for
the present, remain und(^ci(lcd.
The " unstainable portion " of the cell body — that is, the
ground sul)stance — though jtrobably functionally mucdi more
important than the " staiiuible," is not so well understood; its
nature and structure are still as obscure as those of protoplasm
in general. It is here that the so-called fibrils of the variou-: in-
vestigators (Flemming, Apathy, Lugaro) occur. In this ground
substaiu'e, aside from the Nissl bodies, very fine granules or
TH)dul(> formations can be demonstrated whi(di stain with ery-
throsin and with acid-futdisinc (Ueld's lu'urosomes), and in cer-
tain parts of the neu'-ones these are arranged in rows, thus
bringing the nerve cell into agreement with what has been ob-
served in animal cells generally. The ground sul)stance is eas-
ily vacuolizable, and the erythrosinophile granules apparently
represent the luxlal points of the mcshwork which results from
the vacuolizaticm, though sometimes they appear to lie in the
vacuolar cavities. With suitable methods not only can longi-
tudinal markings coniu'cting the I'odal jxiints be made out, ])ut
also more di'licatc transverse markings. As to the physiology
of the various elementary histological constituents, we can say
but little, 'i'he nucleus doubtless presides over the functions
of nutrition. In some way or am)ther the grouml substance
conducts what we call lu'rve impulses, whether as a whole or by
means of tibi'ils, a network, walls of honeycomb spaces, hyalo-
plasm, rows of neurosomes, Apathy's conducting primitive
TllK INTKUXAL MOUrilOLOdY OF NKL'UOXES. l.:,7
(il)rils, or Kngelniaiin's loii^'itudiiiul rows of iR'urotiifjfnu'ii ;ul
noriiium iiiotajfiiu'ii, we do not know.*
Should iiitt'rct'lliilar siiltstaiici's otiu'r than thi' lympli and
lunxroirlia, of a lll)riUary or more honio.m'uoous nature, sonu'tinie
he dcnumstratt'd, it wouhl not he surprising?, hut tiius far the
proof for the existence of such suhstaiu-es is wantinj?.
We can scarcely hope for a clearer understanding of the
structure of nerve cells until our <i;eneral cytolo^ncal knowledge
has l)een extended. If too great a degree of importance aj)-
pears to have heen attached to the work which has heen done
upon the structure and nature of the suhsta^ices within nerve
cells, two ideas have inlluenced me ; in the first place, tiie topic
is one which has been too little considered in tlie text-l)ooks
and too little respected by research workers in neurology ; ami,
in the second jilace, the bibliogra])hy is becoming so comi)lex,
and in places so confusing, that I have felt that a connected
resi'iiie of the work of others, together with an ex])ression of
opinion regarding the relative value of the ditferent researches
based upon personal studies in this Held, might not be unac-
ceptable to those who from want of time or other reasons might
find the hibliograi)hic studies Iturdensome.
One thing is certain : before v/e can hope for a satisfactory
pathology of the gaiiglion cell, we must luive before us clearly,
as Nissl states, a shar])ly defined aiuitomy of the nerve cells.
The establishment of any relations, no nuitter whether they be
structural or functional, so long as they are constant, must al-
Wi'.ys l)e welconu'd. We are too often iiu'lined to undervalue an
enthusiasm for facts, especially when these at the first view ap-
pear ti'ivial and insignificant, but we have been taught the folly
of such depreciation more than once in the progress of aiui-
toniical and especially of histological knowledge.
* The goneral physiology (iml [lallidloy;;' of tlic lu'iirdiic will lie coiisidi'ii'd
ill Section V.
/I
H
^1
l!
I
;
•
ii
SECTION n\
TUE HISTOGENETIC RELATIONS OF THE NEURONES.
CHAPTER XV.
TTIi: OHKilX OF THK XIlKVOrS SYSTKM I\ Til K KMItUYO AXD
THK KAKhlKST II ISTOO KXKTIC STAOKS.
Embryoldgy of the nervous system — The nietlullary phite — Tlie neural
tube — Primary oercbnil ve^iieles and tlieir derivative!? — S|)oiifj:i«ibhists
and neuros|jonfiium — The marginal veil {RantlKchltitr of His) — (ier-
minal cells {Keinize/len of His) — The neuroblasts — Origin of axones and
dendrites.
1Iavix(; had so imu-li to say concerninjr tho external ap-
pearances and internal strncture of nenrones in late embryonic
and adnlt stages, it would scarcely be fair to close these nior-
pholoftical considerations without dealing to some extent with
the forin-reliitions to be net with in the domain oi the lu'rvous
system earlier i i the history of tlu' organism. For not only has
the study of the emliryology of the nervous system, as I have
pointed out, contributed enormously to the development of our
modern conception of nervous organiziition, but the investiga-
tions, on account of the accuracy witli which they have been
pursued, and especially in view of the light they have thrown
upon processes and arrangements which before their advent
were almost hopelessly unintelligible, are surely worthy of our
serious attention aiul command our th.ankful admiration.
The study of end)ryology attains its maxiuium of interest in
the consideration of the development of the human nervous
system. It is not my intention at this time to review what
must already be familiar to all — the processes of fertilization and
of segmentation, the fonnatiou of the medullary plate aiul of
the nu'didlary groove, the foreruntiers of the nerve tiU)e — nor to
descri])e how it is that the three bidgings (anterior, middle,
and posterior cerebral vesicles) at the head end of this simple
158
r I
IIISTOOENETK; KKLATIoNS ok TlIK NKUKONKS. l;Vj
tul)t' ( Fi<,'. MS), wliicli corri'spoiKl, the ///'n/ to the fore-brain (telen-
ei'})haloii) and ijit('r-I)rain ((liciiccphalon), tlic smiinl to the mid-
brain (niesence])iialon), and the Ihinl to the hind-brain (nieten-
Iktuljuhl.
Neuro-
poruH-
Head-plate j.
Foregut y
Yolk-vein-^
Mtitulliiij/
groove i
Ant Til))-
vt nil nil
vesicle.
Middle
ceiehml
ri'Sicle.
Posteriiir
ceri'lirtU
ctsicle.
Heart.
Somite.
Flo. HS. — Aiitcridi- iiortiiin <pf' tlit' Imdy dI" ii cliick. tin- liciid (listiiutly (liU'cifiiti-
att'd : seen tVoiii the siirtiicc. i Alter, I. Knlliiiaiiii. Lclirliiicli dcr Kntwickf-
IniifisfjfSfliiilitt' (lis Mi'iisihiii, .Icua, isitfs, S. l!)!t, Fi^. VM. >
cepluilon) and afler-brain (inyelenceplialon), irradually nnder^o
those nietaniorplioses wiiicli nltiniatcly yiehl the ('oin])Iicated
brain strnetnre eharacteristie of tlie adult.* The reUitions will
*Tlie results of tlie studies of His upon t lie gross Tnorphology of the
iiuniau nervous system durinir ilevelopnien>" have been made aecessihle to all
tlu'iiutfli his puljlications,an(ies|ieeiallybymeansof an exeellent series of exact
wax-moilej reimxluetions. Hased upon these we have been supjjlied for tiie
first time, too. with a nomenclature for tlie nervous structures wliieii iiu'cts
the (lemands of eml>ryoloi,'y, comparative aiuitoniy. and clinical neurology —
a noinenelature the use of which I can not U>o strongly recommend to those
who have occasion, in writ in!; nr teaching, to make use of lu'urological terms.
Cf- Section Neurologia, in I)ie aiiat:)inische Xomeiielatur, Nomina Ana-
tomiea. Vei'zeiehniss der von de
atomischen Gesellsehaft auf ihrer
ix. Vers, in Hasel angeiiomnieiieii Naiiu'ii, Eingeleitet unil erliiutert von W,
/I
I
\
l;
'!
( !
I
!'•
ino
TlIK NKKVOL'S SYSTEM.
hv surticioiitly clear if the rciulcr study ciircfully tlu' (liafjriinis
(l''i,irs. S!i-!l-.') here iiiscrtcil with tlu'ir iipprnpriatc U'j^'ciids.
Fid. Si(. .Median si'ctiim tliroiifili cmljryo liimiun l>raiii at tlic cud of llic (irst
niciiilli. i.M'lcrW. His. .Krcii. I'. .Vnat. ii. IMiysinl.. .\iiat. .\l)tli., i^ciiiz., l.SiKJ. i
1. .MvclciiccplialiilL.
I.-', rarsddisili.s.
II. .Meti'iici'|i]ial'iii.
II. :.'. ('(•icImIIiiiii.
irr. Istliniiis.
HI. :,'. Hracliia (niijiuicliva, Vd. iiu'd. ant.
I\'. Mcscncciiiialon.
I\'. ;.'. Ciirpora (luadilKcniina.
\'. OicnccpliMldn.
V. I. I'ars iiianiiiiiilaris liyinitiialaiiii. V. ^. Tlialaniiis.
1. 1. Pais vcntralis,
II. 1. I'.nis.
n I. I. I'cdiMKiili CI rchri.
1\'. 1. I'cdmiciili ccrcliri.
V. 15. Mctalhalanu
y. I. I'piliialanuis
YI. 1. Pars (iptica liyi>c>tlialanii.
\'l. 'rcicnccidialnn.
\"l. )l. ( nrpus striatum
VI. '.i. Hliincnccplialon
VI. 4. Pallium.
His. r.cipz.. ISO."). 'IMiis noiiu'iiciatiirc lias been closely followed in tlie
jircsent book, except, that I have substituted the worJ.s ventral and dor.sal
!
IFIST()(iK\l''/ri(' K'KFiATIONS OF TIIK NKIUON'KS. jr.l
Tlic derivatives of the tiirt'c ccrcliriil vcsicli'S an- outlint'd
ill the iiccoinpiuiyiiif? table on paije lt>;{.
Nor sliall I periiiit iiiys'-lf to (li<rr('ss and tieserilu' to you how
iVom tile iiioiiieiit of fertilization, t liroii<(liout the jfradual process
1. !•(). Miidcl III' (IfvcliipiiiK liuiiiMM liiiiiii. I Al'lcr \V. Mis, Anil. I'. Aiiat. u.
I'liysiiii., Aliat. Alilli., iK!l:i. i />';•., imns curve : T. «., cliiasiiiii niiticiMii ; <'.sl.,
(•(irpiis stiiiitiiiii ; /■,'., iiiniiciitia iiitciiicdunciitai'is nl' tlic isllinms; /•'.(•//., tis-
sura cliiiriiiidca ; /•'. ('.. I'ossi iiiliT|n'(luii('iilai'i.s ; ///)., ttuniciilal iinijcctinii ;
//r/(,, (1 rclicllar litiiiisiilurc ; /.. istlini'is : /,. ^, lamina tiiiiiiiialis ; .1/.. ciir-
piis iiiaimnillai'c ; .l/A., I'nol' nt iiiiil-lnaiii : I', s.. liyiiiitlialaiMiis i pars sulilliu-
laiiiica ' : r. I!., aiilrriur iiitactmy lulic ; h. It., puslciinr ulCaclnry I<i1m' ; I! ;/.,
rcccssiis Kciiiciili ; A", in.. I'cccssiis iiiaiiiiiiillaris : I!, i.. rcccssiis iiil'iiiKliliiili ;
A". ()., rcccssiis iipliciis ; S. m., sulcus .Miiiiidi ; 7' !■., tul)cr ciiuTcuiu ; 7V/..tlial-
aiuiis ; /.. ccirpus piiicalc.
for ttiiti'iiiir ami /mn/mor rfspcctivclv, iind i)i'rliai)S in )i few other piir-
ticulars. Why the roniinissioii on Noiiu'iichiturc, usually so lia|i])y in its
decisions, nejifleeted to use the terms ventnil iind dorsal, instead of anterior
and posterior, witli re^jjard to the roots of the spina! lu-rves. I find it dillicnlt
to undcrstiind. 'I'ho nonienchiture ejalioraled l)y I'rofessor W'ihler, of Cor-
nell University, is used by a lartfe iuunl)er of American anatomists, and
.Mills has followed it consistently in his recent clinical text-book. 'I'he
terms of Wilder and the e(|uivalent terms of the IJasel Cummission are to
lie foinid in the article of I'rofessor IJ. (i. Wilder, entitled •' Neural Terms
— Intt^rnational and National." .1. Comp. Neurol., Granville. ().. vol. vi
(1H!)6). |ip. '.il()-;5ij2. in order to save space they have not been introduced in
l)rackets in this book, but the reader accustomed to this nomenclature may
refer to l'rofe.s.sor Wildcr's tables.
'J I
i,
iMil
(i;
Fl(i. !M. Mrdiiin section offu'tal liiiiiiiiii l>riiiii diiriiiK the tliird iiiontli.
(AClcr His. Arch. f. Aiiiit. n. I'li.vsii.l.. Anal. Alitii.. IWi:}. S. 175,
Kij;. 2.1 Tlic Icllcriiit' is Ik lie intci'|irctctl in llic siinc wa.v as
tor Fis.^NK. 1 I ■(//(■ Kiiiirii.i
Sulcus cinguli
(lulls iiKiiyinalis).
Sulcus cinguli (/in i:i siiJifrontiilis).
f'-Ki. 02. Median section tlironfjli adult Ininian
brain. lAt'ti'r His. Arcli. I'. Anat. u. IMiysiol.,
Anat. Al)tii., IMIW, S. 17(>. Kifi. 3. i Lfttoring
.same as in Fin. Wt. (, Vide siipni.)
a
o
at
® M
^ *-*
<D I
fi M
O
ji
c
"a
0.
z
c5
tJD
a
o
^ §
«8 C-
I Mr i !
4
llI.sTOdKNKTIC KKLATIONS (H' TIIK NKllioNKS.
103
'3 M ^
ft 1 -S
® J. =3
S M -
F
»
t^
u
•o
A
2 i
5
//
^ »
13
o
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0) I
^ M
a
o
s
a
a.
e
'^ 2
2
c
i
J*
mi
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i
s >::
"3 '5
B H
ST
4«
a.
w
s
w
s
w
.a
o
u
= c-
c c
;ji
it
%>
as
sS
C
'51
^
i
•-
^
c
r
2
%
_
K
u
u
— ■/;
■r.
3
"5
"3
3
L-
'u
~" ^
™
2
E
X
k,
x:
F!
~ 'fl
■a
(.
P-t
6
c
3
13
2
■A
S3
15
'a,
&3
cZ
—
c
s
9;
a-
&,
C
C-^'
•^
aj
■»— '
1— 1
^
^
^
^ "^
c«
n
■♦
«
n
«
=
—
^
»-»
^
*^
1^
r^
1^
>
>
t-
<>!•
ISOA
,1I.)IS0.\ |1!.I(^
^1
)isaA
\\ui\MM joiaaviv
inj(1<)joa
jouo4so,i
-OJOO
'»n'P!i\
■:(-(
I,
'i
"nl'
i»;4
TIIK NKUVOL'S SYSTKM.
of tli»Ml('vi'li)|)mciit of tlic cmld'yo, iiilliH'iii-cs of (litrcrciit kinds,
siii'li !is viiriiit ions of li'iiipcnit urc, ol" the i»xyj,'<'ii supply, ami of
other coiKlitioiis of ciiviroiiiiH'Mt, or truiiiiiii it'ii(liii<,' to injury of
portions of tlif v^iii or of the sof^iiicntution cells, eiin j^ivc rise to
those imfortiiiuite ('iirieatures of human l)einj,'s which we coiii-
nionlv ilesi;,'nate as monstrosities, iind foi- the ori<;in of wliicli
experimental leratolo^a has (lurin<r the past few years heeii
attempt inj,' to supply us suitahle explanations.*
The histo^jcnotic relations «)f the neurones ami of their su|)-
porting structures must, however, he dwelt upon hriefly; and
the des(!ription here given is drawn lar^'ely from the wrilin<,'sf
*('!'. lii'iiclii, ('. 'I'craliildfjic. Liilpiir>cli-< (slfilii;;. I'irp'lniissc dcr all-
jji'iii. palliol. Morplml. ii. I'liysiul. Wicsliailfii (IHJI.'i), S. ."iJl.
f The principal inihlicaliinis nf \V. His which arc inlcn'sliii;,' in lliis cdii-
ncclioii arc (I) Analuniic nicnschlichcr {•liiiliryni en. lii'i|)Z. ("i) I'dicr die
Arifiin;,'!' ih's iicriphcrischcii Nci'vcnsvslciiio. Arch. f. .\iiiil. ii. i'hysjol.,
.\iial. .\htli., l-cipz. (IH71)), S. 4rM-4H2. (!{) Ziir Gcsciiichtf dcs inciisihlichcii
iviickciiiiiai'kcs unit <lcr Ncrvcnwurzclii. Ahii. dcr iiialli.-|)liys. Cl. dcr k.
siichs. (i.s. .l.T Wiss., Md. xiii, No. (i, JA-ip/.. (IHHfi). S. lT!l-.-)i;t. (4) /iir
(icschichti" dcs (iciiiriis siiwio dcr cciilriileii mid pcriphcrisdicii Ncrvt'ii-
liaiincn iM'iiii riiciischlichcn Kinliryo. Ahhaiidl. d. iiialli.-|ihy.s. CI. d. k. siiclis.
(iescllsch.d. Wisscnsch.. I5d. xiv. I.cipz. (IHHT-'HH). S. ;i:{!»-:i!r2. (.->) |)i.. N.-u-
niblastcii mid dcrcn {•'.ntslchmi;; iin (!inl>ryoiiHlfn Mark. /Iiiil.. Md. xv,
No. 4. I.cipz. (1M8!)|, S. :!1:{-;!T2. (0) Die Foriiicntwickclmii,' dcs nicnscli-
lichcii X'ordi'rhinis voin Kiidi' (les crstcn liis zmii l)cj;imi (h's drittcn Moiials.
l/iii/.. {{(1. XV. i.eipz. (1H81»). S. (i7;i-r;«i. (7) Die KMlwickeluiif,' dcs ineii.sch-
lichcii IJautcidiirns vein Kiidc des crsti'ii l)is zmii |{cf,'iiin ilcs dritliMi ;\Io-
iiats. I. V('rh'iiij;crti's .Mark. ////(/.. i?d. xvii, i,eipz. ( IMiH), S. 1-74. (H) Znr
allgciiii^iiieii Morpliolof;ic des (ichinis. .Vrch. f. .\iial. u. Physiol., .\iial.
Al)lli., Leipz. (lH!r,>). S. :i4(h-:5S;?. (») t'elxT das trontale Kiide des Ochirii-
rohrcH. .\rch. f. Aiiat. ii. I'hysiol., Anal. Al.lh.. Leipz. (IH'Ki), S. 1.")7-I71.
(10) Vorsddiige ziir Hinllieilung: des (iehinis. /hi, I., S. 172-17!». (11) Ueber
iiieclianische (Jrmidvorgiingi' lierisclitT Fornioiiliildmij;. ,\rch. f. Anal. ii.
Physiol., .\iiat. Ai)lh.. Lcipz. (lHi>4), .S. \-H{). {V2) fcLer die Vorstiil'en der
(iohini mid der K'opfbildiiiig bei Wirbellhiercii. lliii/.. lHi)4. S. ;5i:{-:i;{«».
Korllie rojiorls of two iiit crest in^; addresses i.pon some of tlicfjeiieral residts
of His's work the reader is referred to ,1) His, \V., Ilistoji;enese tniil Zusain-
nieiiliaii},' der Nerveiielemenle. Vorldiaiidl. d. x. iiiteriiat. nied. Con};. l?erl.,
4-!». .\n^., iHilO. M. ii, S. 0;5. l?erl.. lSi)l ; ami (12) His. W., I'eber den Auf-
l)au unseres Nervtinsystenis. licrl. klin. Wchnsehr. ( 1 SO!]), S. 1)57 mid !)!(0.
An excellent critical review in FInglish of all the literature uiion the devel-
opment, of the liuman nervous system in its early stajres is to be found in
C. S. Minot's Mmiian Kmbryology, pp. r)9;{-743, and in the article by the
same author entitled Die friihen Stadien und die Ili.stogenese des Nerven-
systems, in Merkel-Honnet's Krjfebnisse der .Vnatoinie und Pintwit^kelmifjr.s-
geschichle. Hd. vi (for 189(5). Wiesbaden (IHi>7), S. 087. The subject, is also
II
and leet
which, ai
layer of
eetohlasi
which jj
skin aiM
— is mad
layer of i
lial eelh
side (V\'fi
correspoi
ends of 1 1
represent
and, afte
iniu'r an
faee of t
its ori^rii
the epith
iiiit form
Fi<i. <•».— .S'
lie<;iiiiiin;
iiiieh'i is
(lid'en'nf
Twii hiriii
iiiiiei' siirl
11 J) of the
very diit'ei
plasm of 1
clearly firesc
des ISfensclK
fer, of Muni
IIIS'lVMiKNK'IIC |{|«:i,A'ri(»\S (»!•' TIIK NKIUONKS. 1(^5
:iii(l lectures (if Mis. A I an early period, the mediillarv plate —
which, as everyone kiiowH, hu« its (iri;,'in in t!ie external leatliko
layer of the cinhryo, the
cctohlast, the same layer
which j^ivcrt rise to the
skill and its appenda*;e.s
— is niatle up of a siiij^le
layer (d" niicleated epithe-
lial cells placed side l»y
side (Kij,'. !»;)). The planes
corresponding to the two
ends of theepitliclial cells
represent, the upper and lower surfaces of the niediilhiry plate,
and, after the foniiation of the inediillary or neural tiihe, tlw
inner and outer surfaces of the wall of the tiihe, the inner sur-
face of the wall of the tube thus ohviously correspond in;; in
its ori;,nn to the outer surface of the einhryo. The nuclei of
the epithelial cells of the plate do not all lie at the same level,
hut t'orin several rows eorrespondiiiir to dilTereiices in the dis-
trihutioii and arraiij^e-
^/ '
t'lo. !KV — Sccliiiii tiifniiKli iiifdMUniy iiliili' of
r!ilil>it. Aniiiiiu iIk' I'liilliilinl icIK w \\w\n-
niiinil (.'rniiiiiMl iill willi I'Iriir |irii|ii|il;isiii
is \ i>i)iU'. ( Al'lii- His. )
iiieiit of the ])roto|)lasm
in the individual cells
(Kif,^ !»4). 'I'he nuclei
are rarely, however, situ-
ated at the ends of the
cell, so that very soon
tlu' medullary plate, as
seen on transverse se(v
tion, can he divided in-
to three more or less
I.-,.,, .|...-S...ti..n lln„u^'h n..nr:,! tul,.. ^^l>i..h is 'I'^tinct ZOIies— a U.id-
iMtiiiiiiiiij; i<i rldsc. 'I'lij' iiumlHi- 111' iiiiilicliiil die zone coiitaiiiin;! the
nuclei is ciiiisidcnilil.v iiiiTciistd, miiiI in tlic , . , , ,
iliiliiciit colls ihcy (Id not licat tlicsiiiiK' l.vci. uuclei aiul two honler
Twii liirtic Kcnniiiiil cells arc visible I.. wiinl tlie „ ,,,,.^ f-ee from nuclei
inner smlMce. ( Allcr His. ) /Onts ir( ( iroui 11U( K I.
These last two are made
up of the proto])lasmic ends of the epithelial cells and behave
very dilferently in their further diit'erentiation. In the proto-
plasm of both ends of the epithelial cells hyaline areas reseni-
clciirly prcsi'iitcil in .1. Kolliniinirs Lelu'ltuch der Kntwickcliuigsgcscliiclite
(Ics Afc'riscluMi. .I(Wia. 1808. The many viduaiiii' contributions ef vou i\u|>f-
fcr, of Munich, may also Ix- referred to.
■'it I
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TIIK NKHVOUS SYSTKM.
l)liii;f Viiciiok's soon appciir. In tlic distal ends of the ct'lKs
(tluit is, the t'lids (lirt'cti'ii toward the outside of the Ixtdy
in tile medullary plate, or those directed later toward the inside
of the inedullarv tui)e) tiu' cell bodies tend to collapse so as to
form a series of striated })illars with siiaces between the indi-
vidual cells. The free ends of the
cells retain their orif,nnal breadth,
and with those of neif,dii)orin,L,' ci'lls
form a thin lijuitiiifj; membrane.
The proximal ends of the cells, in-
stt'a<l of collaj)sinir, assunu'ara<r<fed,
irre<fular appearance, the proto-
plasm bccomiiiif, accordinji: to Mis,
manifoldly perforated, so that the
framework between the pi'rfora-
tions yields a reticulated appear-
i'lice (V\ii. !>/)). For a time the
boundaries between the individual
cells at the proximal ends are
easily disceriiil)le,* but very soon,
throuii;!! further developmi'iit and
extension, the cell boundaries dis-
appear, and we liuve the appear-
ance of a spongy network or of a
Via. 9.1.— Section tlii<.u«;li wall oi' ,.|,)h -ly felted thicket, the neuro-
iiciiral till)!' al a later stai;e. . ,. 1 1 • ni i
Dimieiiiiaiioii cif 111.' two ends sp«)n^num ot 11 IS. Whether we
' ^"'•'' lijjve to do in the thread work with
an actual closed network seems as
yet not (piite certain. Kanion y (ajal, fnmi the study of silver
preparations, denies this, aiul also (lih])utes the independence of
the cell territories which His maintains for the nctii-ospon<rium.
This thicket, which in the closed medullary tube forms the
periphery of its wall, becomes more and nu>re complex with
further deveii)])ment. The feltwork, at lirst extremely close,
shows later wider meshes, the whole s])on<ry structure formin<i
a /trri/i/irrd/ or iniir(/iii<i/ rril — the liiiiKlschhii'r of His. .Vs we
shall see presently, the threads of this veil form a scaffold in, <,' of
tine beams which later appear to play an important mechanical
role in determininff the course and direction of the developin>r
oC the epithelial cells
Mis.)
*'i'lie epitlieliiil cells at tills stiige of ililTerent ijilioii are .-pnkeii of liy
His as spoii)j;i()blasls.
'
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IIIST()(}KNKTI(" UKLATIONS OF TlIK NKL'HONKS. n;7
ncrvo fibres. Indeed, the mnrfxinal veil persists tlirniifjchout
life iiiid appears to correspond in the adiUt to a part of tiie
epeiidynial framework of tiie white matter of the whole of the
central nervons system.*
Very early in the history of the mednllary plate there are to
he made ont in the intercellnlar spaces of the l)order zone, wiiieh
<'orresi)oi\ds to tiie distal ends of the epitiielial cells, elements
whi(di have an entirely ditferent appearance from those just
described. These elements are desiffiiated by His as germinal
cells {Krinizcllni). Tliey are, as a rule, at first splierical in
shape, jiossess characteristic clear protoplasmic bodies, and
their nuclei in well-fixed preparations are usually seen in the
process of rapid division i)y karyokinesis ( Kig. !»(!). The exact
relations of these cells to the epitiielial cells before lieseribed
and to tlie other cells of the ectoblast still form the suliject of
some dispute. Tlie idea that the Kfiinzi'llcii are fundamen-
tally ditTerent from the epithelial cells has been vi<,'orously op-
posed by Kolliker,t S(diaper,J. and N'i^nal.** The wiiole mat-
ter has lieeii very recently subjected to a critical revit'w liy
Scliaper.|| It is ur<j;ed that the KcinneUen are really only
♦As His lias poiiili'd oiU. llic tniiisforiniition of (>|iitlR>Iial cells into a
rraiiu'WDrk jit'iii'trahMl hy s[)ai'('s ami boiinilt'd liy liiiiitmj,' iiii'inl>raiics is not
|ii'culiar to the iiu'iliillary plate. N'im'v similar foi-ms arc to la . with iii
otlitT t'cloblastic ilcrivatives — for cxatiipli', Ilic rctiiia, Ilic oar. tlic olfactory
[ilatf, and llic portions of Hit' fcloldast adjacent to tlic nenral j^roovc wliicli
<'orrcs|ion(l, in part at least, to the building [ihux's of the cell- (f the sensory
ganglia.
+ OiK rif.
:(Schaper. A. Znr IVincrcn .\natornie des Klciniiirns tier 'relooslicr.
.\nat. Anz., .lena, IM. viii, ISlKi, S. 705-720. — Die intirplioltjgische nntl hisli>-
itigischc l']ntwii;Uelniig ties Kieiidn'ms tier Telcosl icr. I/iii/., IJd. ixllHli;!-
■!»4). S. 4S!»-r)01 ; also. Morpht>!. .lalirb.. l.cipz., lid. xxi (ISU-l), S. (;'J.-)-70S.
* V'ignal. \V. Keelierehcs sur le tli'vcloppcincnt des t'lt'nicnls ties couches
cortieales tin ccrvean et tin cervclet chey. I'lioinnie ct les inaniinifi'res. Arch,
tie jihysiol. nt)rin. et path.. Par. (ISSS). 4. s.. t. ii. pp. 2',>H-'jr)4 et ;511-:i;{S.—
Kecherches sur le tit' eloppoinent ties t'lt'nicnts ties conches cortieales du
ccrveaii et du cervelet ehez riioniine et les inainniifi'res. ftcole prat. <1.
halites t''tnde.s. Lab. il'liistol. dn Coll. tie France. 'Pniv.. i'ar.. ISSM. t. xii.
pp. 54-8'.^. — Rechcrclies snr le th'velt.ppeineiil tie la substance corticale tin
cerveau et du cervelet. f/iid.. pp. H:i-I !'.».
1 Scliaper, A. Die fri'ihesttMi DilTereiizirnngsvorgiinge ini Centralnerven-
.systcm; kritisehe Stiitlic nntl Versiich einer (lesehichle tier Kntwiekeliini,'
nerv."si>r Snhstaiiz. Arch. f. Kiit wcklngsniechn. d. Organ.. Leipz., I$il. v
<IHi)7), .S. .si-i;w.
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youw'fi proliferating forms of t'j)itlieliiil cells wliicli utTonl iiiate-
rial for a jjeiieratioii of iiiditTerent cells. Tliese latter may
be further difTereiitiated either into nerve cells or into f^lia
I''l<i. !M>, — I'licildinicniKnii)!! liy A. (i. Ilni'ii IVuiii n spi riiiicii nl' li. (i. Ihiiiisipn's
tliriiii^'li the niiniil lull'' of ainlily.stdiiia. Scvcnil cells undcfyiiiiif; (livision
l>,v kiiryiikiiicsis ciiii tic seen in llie inner ziine. A liirfte niinilier oreiiitlielial
nilrlei are visilile. '{"lie oilier /one ol' the wall of llie lube, which is free from
nuclei anil somewhat iiidislinclly shown, corres|ioii<ls to the re;iion of the
inaiKinal veil.
cells. Scliaper has observed up to a certain period of dcvelo})-
mcnt direct trtinsition forms of h'ciimcl/rit to loiifj; epithelial
cells, and pictures them. The number of spongioblasts (in the
sense of His) is not sutticient to account for the origin of all
the glia cells.
The spherical sliape of the germinal cells is soon lost in the
majority of instances, since at the extremity of the cell origi-
nally directed away from the outside of the body ii short blunt
projection appears which Ititer becomes extended into a
longer, more delicate process (Fig. 07). In silver preparations
this process shows a conical i»ronged end knob, prob;i])ly corre-
sponding to the division of the fibre later. The protopliism,
also, instead of reniiiining eveidy distributed throughout the
IIISTOOKNK'I'IC inOF.ATIONS (>K TIIK NKIWONKS. l<i<»
vt'W l)o(iy, ti'iuls to iiccuniulati' at tlu' point of ori<>iii of tlif jn'o-
ccss, forming' a fcchly striated ])r()toj)Iasiiii(' coiii' on one side of
the nucleus from wliidi the j)rocess ai>})ears to take its orifjin,
Tiiese pear-sliajx-d cells, the derivatives of the Kviiii/vllni, are
termed by His ni'iirohltists. The nucleus of the cell body of the
neuroblast corresponds to that of a future lu'rve cell, and the
'sin<,de ])rocess represents the developin<j axone. Oi the exist-
enci' of dendrites there Is at this period of development no evi-
den<'e, and studies in histogenesis liave shown us that the
dendiites appear ontotfenetically mucli later than the axone,
the latter l)ein<; the first process of tho younjr nerve cell to
ai)pear and for a lon<f time exist iiifr alone, a fact that is of
especial interest, as His sufjjjjests, when we renu'inber that in
m
Vui. !t7. — Scclidti of spinal cord of a ctiick at tlic tiiinl day of iiiciilpatioii. (After
Kaiiioii y Cajal. ) ;/;;. cells of spinal (Jiaii^lioii : iU{. ends of cells upcni wliicli
the ileiidrilcs develop later. At the ippposile ]ioles are sliow ii the eiiiliryonic
axoiies. at the extremities of some of which there are liiilhoiis swellings.
The axoiies of the spinal Kan^rlion cells divi(l4' on entrain-e inln the coi-d. /■.
rent., ventral root.
the young liirvic of frogs iind fish before the feltwork formed
by the dendrites of the nerve c"lls has ajipeiired ttt till, there are
already in fidl iictivity physiologictil mechanisms of no incon-
siderable significance and complexity.
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("IIAI'TKIi XVI.
TMi: DKVKLOPMKXT.VL MISTOKY OF I'lIK SIMNAI. (OKI) AM)
MICDfLLA ()I!L()X(iATA.
Wuiidcrinjf of ii(Mirol)lasts — I''!it(.' of llic axoiics in the spinal cord — Forma-
tion of ventral roots of spinal norvi's and of the intrinsic tibrcs of tlio
white fnniculi of the sijiiml cord — Tautoineri(\ hetcroineri(!, and licca-
ioroiucric neurones — i*'asciculiis ccrchcllospinalis — Wandering- of neuro-
blasts in the nieilidla oblonj^ata — Developmental history of the motor
nuclei in the medulla, the forniatio reticularis, the olivary Ijodies, and
the pyramids — Helations of the white and avuy ma.'tor in the cerehrum.
TiiK lu'iirobliists possess a ccrtiiiu degree of motility iiiid are
capable of tilteriiig their position. Following the nidiatiiig
paths which corresjxnid to the spaces between the epithelitd
cells of the inednlliiry phite, they tend soon to leave the border
zone at the inside of the nerve tube where they first appear,
;itid to wander ont toward the miii-ginal veil, there to form often
ji sort of matitle Itiyer (Fig. OS). In the mtirginal veil they tip-
pear to encounter tin ol)stacle Mch prevents their fnrther
progress, although they nuiy succet •, in penetniting for a short
distance into its meshes. The ganglion cells occasionally met
with fiir out i«i the white mtitter of the iidnlt spintd cord tire to
be looked upon iis cells which have been tible, through their
active mobility in the neuro])l:istic sttige, to atttun a position
more peripherid than tlnit reached by their fellows.*
The viirions wtinderings of the different groups of nerve
cells in the huiniin cord have becji ciirefnlly followed, f In the
* His has noticed in selachian embryos occasionally cells which have even
been able to reach the external border of the marginal veil, although they
appeared afterward to l)(>come again surrounded by its meshes. Dohrii be-
lieves that in the region of the nervus oculomotorius there may be a peiiiia-
nent exit for motor cells. lie brings these cells into connection with the
oculornotorius ganglion of Schwali)e.
t His, W. Zur (Jeschichtedes ineiischlichen IJiickenmarkes iiiid der Ner-
venwurzolii. Abhandl. d. math.-phys. CI. d. k. siichs. Oesellscli. d. Wis-
sensc.h., Leipz.. Hd. xiii (l«8fl). S. 4T0-.")l:!.
170
wm
inSTOGEN'KTK' UELATIOXS OK THE XEURONES. 171
forniatidii of tlu' iiuuitk' layer of iuMirol)last;^ tlio colls in tlio
dorsal half li'ud to wantlor toward tin- ventral iialf and their
processes are nearly all directed ven-
t rally, the neuroblasts underjjoin^, as
it were, a partial turning so as to he-
coine ]»arallel to the surface of the
niar<jiiial veil. Of tlie cells of the ven-
tral half, a portion lyin<f <frou}K'd to-
gether inside the marginal veil pos-
sess j)rocesses which, uidike those of
the other neuroblasts, penetrate direct-
ly through the marginal veil to ap-
pear outside the embryonic cord, form-
ing the ventral roots of the spiiud
nerves. The cell bodies of these neu-
roblasts represent the n .tor cells of
the ventral horns of the gray matter,
aiul their processes the axones of the
motor spimil nerves (Fig. '.)!»). The
ju'ocesses of the other neuroblasts do
not go througli the marginal veil, but
renuiin within the spitial cord. The
majority of them can advance, hov.-
ever, for a certain distance into the
meshes of the lu'urospongium, but
sooner or later meet in it with opposition, according to His,
which leads to the directing of the processes upward and down-
ward (Fig. 11)0). Hence arise the axones of the intrinsic iibres
of the white funiculi of the spinal cord. Those of the neuro-
blasts which send their ])rocesses to help in the fornuitioii of
; iie white matter of the same side of the cord correspond in the
adult to the f<(iitoiiivric* neurones; those which send their
processes through one of the commissures to the white matter
of the other side, to the lirfcronicrii- ] lunirones (Fig. 101) ; and
those of them whose processes divide into two, one going to
each side of the cord, to the /irrtiffrdiiirrif I lu'uroiu's. Tht^
majority of the intrinsic tibres of the cord seiul their processes
n;. its. — Si'ctioii tliroiisli liiilf
nriicmal liilic sliowiiij' till',
IHiir - shaped nciirolilasts
wliicli arc waiiilcriiiK mit
tci I'linn a sort nl' niaiitlr
iipiiii the inner siirt'aee of
the inar<;iiial veil. The
axones of some ( t' llie neii-
idlilasls liave peiietr.itecl
through tlie veil to lorni
the ventral root of a spinal
nervi'. (Alter Ills.)
* A very satisfactory iioiiieiielaliiiv siij^i,'esto(l by van (ielmclileii. 'I'ln;
word ttmtomefie is taken from the (ireek rh aurh /xepos, tlie same side,
f From fTfpou fiepoi, tli(> otin^r side.
!(. I'^roin fKaTfpov nfpos, eticli side.
i:
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17l>
TIIK NKUVOl^S SVSTKM.
into the vent ml jitul lutcral funiculi of the white miittcr. Of
the liittcr, ii liirj,'!' bundle known as the fiiseiculus eerebellos])!-
nalis (direet cerehcllar trurt) receives its axones from the ^roup
of cells situated in the nucleus dorsalis (Clarke, Stillinf^).*
("oiuparatively few of the neur(>l)lasts send their processes into
the rejifion of the dorsal funiculi, these, as well as the re<,non of
the pyniniidal tracts, hein^f occupied in the adult almost en-
tirely hy nerve fibres which may, in a certain sense, be looked
upon as extrinsic to the spinal cord, sine* their axoiu's in their
oiifi'in are entirely independent of nerve cells lyinj:; in it.f
A very marked example of the wandering capacity of neuro-
blasts, and one to which His has frequently taken occasion to re-
KiKiiityiiia
Spunyiubltist
(•'iriiihtdl cell -
Medullary tube
Suiixritntia
ijrhea.
— Suhnlciiitia
lllbtl.
- Deiidiitex.
Aj:<iiuii of (imi-
/ tiir) vent ml
root.
"' Aeitruhlitst.
Via. (Kt.— Triitisvi Tsf scctinii (if the sjiiiial cord ul' a (■lii<'l<. Kft't side t'roiii two-
dav chirk : fi<{lit side fniiii fivc-dav chick. (Allcr.). KdUinaim. Lchrhiich
dci' KiilwickcimiHSffcschichtcdcs Mciisclicii, .Iciia. ISlls, S. r>(M». Fij,'. ;5().H. )
fer, is met with in the development of the medulla oblongata.
In its early staf>;es ( Fi<j. 10'.») the rcfji a of the medulla is more or
less pentagonal in shape, the fifth side being formed by tlie thin.
* S(i far as 1 know, tlic actual coiiiu'ctioii of tlie axdiics of tlio cells of
the nucleus dorsalis with t lie fascicniliis cercbeilosiiinalis lias not been ob-
served, althougli tlie evidence from seeoiidary degeneration and from (Jolgi
spwumens giv<'s suffleient warrant for the stateme':t in the text.
t 'i'he axniies of the fibres of tile pyramidal tracts (fasciculi cerebro-
Hfiinales) have their cells of origin in the convolutions of tiie so-called motor
area of tfic cerebral cortex, wiiile the axones of the majority of the fibres of
tlie dorsal funiculi of the cord represent direct continuations of the central
ax(jnes of the cells of the ganglia on the dorsal roots of the spinal nerves.
i;;li
i i
IIISTOCKNKTIC IfKl.ATloNS ()K TIIK NHlWoNKS. 1 7;{
iioii-iicrvoiis roof. Tlic latcnil iiiul tlio vmitrul walls of ouch half
of tlio tube conform in structure, as rcj^anls neuroblasts and
WS*> • <■ *.d-*-_ . ^5; cy,^ ^<z^ J
S.A.- •
;v/>n
Fk;. 100. — Transverse scctiiiii through tlie «p]H'r tlior.icic sjiiiial cord oftlie liiiiiian
einhryo. (.\fter W. Ills. .\l)liaiiill. (I. matli.-pli.vs. CI. (I. k. siielis. (iesellscli.
<1. Wisseiiscli.. I.eipz.. 15(1. xiii. IM.sii, No. ti, Kij;, 2. I n. M.. external niantUi
layer: ,1. .vyi. n., arleria spinalis ventralis; .1. s/i. ji.. arteria si)inalis dorsalis;
///>., Hodenplatte ; T./', cylinder I'urriiw : />./(., I)e<'kpla1le ; /''.(/., torniatio
areiiala : /. .1/., internal mantle layer; ./. />., internal plate; M.l.m., nieni-
brana liniitans nienin;;ea ; m. M'.. inotur ventral rout: ». />'., oval bundle of
diir.sal I'nnieulns ( /(o^ l''leelisif,''s oval Itundle); li- )'■. niarjjinal furrow; ■•>■. W.,
sensory dorsal root; S.h.. eorini laterale.
spouf^ioblasts, closely to tlitit which I have described as char-
■Krteristic of the spintil cord in its early stages. In the ventral
|)l!ito, in a series of sections, c^an be nuuie out (]uite etirly tlie
"(roups of neurol)lasts corres])onding to the motor luudei of the
medidlii (Nucl. N. hyi)ogl<)ssi, Nucl. N. aocessorii, Nucl. N.
vagi, and Nucl. N. glosso-pharyngei), and at this period these
nuclei, as well tis the buiulle of fibres known as the tra<itus soli-
ii ;
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174
TIIK NKinOlS SVSTKM.
I
fiiriiis (forriicd liy sciiKorv fild'cs from the \. Vii^^iis uik] X.
^l«»KS(i-])li!irviifr('iis, iiiid so iiiiiilojrous to the dorsiil fmiicii'.i in
Fl<;. KH. ( '(iiniiiisMinil cell nr licliroiiifric nciiroiic friiiii tlir s|iiii;il ccpnl of a
rristimiis cinln-yd :{(i nun. Ion};. ^ .Vftcr M. von Lcnlnis.sck. Her CiiniTi' linn
<l(s Ntivcns.vstfin.-.. ilc. IJcrlin. II .\n(l.. 1H!I5. S ^^•^•>. Kiir. Ht'. The iixonc
piisscs llironf;li llic ventral coniniis.siirc into the snli^tiintiji Krisca of the oji-
liositc sidf.
Fio. 102. — Tninsvcrso section tlimuKli the medulla of the linmaii eiiihryo. T. s.,
tr.ictus solitariiis ; A', iiervtis vatjiis ; Xfl, iiervns liypoKlossiis. ( After His. )
the spinal cord), are situated close to the outer surface of tlie
medulla* v tube. As is well known, in the adult the motor nu-
IIIS'l()(iKNHTIC UKLATIONS OK TIIK NKlUoNHS.
«•>
cli'i in the mcdullii aiitl the tractus solitarius arc far rciiiovcd
from tlu' ventral surface; imU'cd, t licy arc situated close be-
neath tlie floor of the fourth ventrieh- (central caiud), hein;;
st'jiaratcd from the surface hy nearly the whole thickness of the
ventral wall of the medulla, iiududin;,' the pyramids, the olivary
bodies, and the formatio reticularis. The explanation of this
is easy when the histo<reiu'tic relations arc followed. Let us
examine and sec what has happened to l)rin^' about this remark-
able morpholo^'ical metamorphosis.
The medullary tube at ti»e stage represented in the fore<fo-
in<i li^'ure on further development shows in tin- hutnan cnd)rvo
a li]tlikc lateral projection result inj; from the ben(lin<f over of
the upper border of the thick lateral wall on each side (Fig. !(»:{).
—ni.
T.s.
Fk;. 1(13. — TriOisvci-sc section tliroii};li tlic iiicdiilla of tlic liiiiiiaii ciiiliryK. ( After
Mis.) A'//, neiviis liyiKPnliissiis; A' :ierviis va^jiis ; 'I', s., llic traeliis soli-
tai'iiis : III., rliiiiiihiiidal lip.
Tins lip, which reaches on each side from the lower end of the
nuMlulla as f;ir forward us the junction of the metente})hiilon
with the mesencephalon — thiit is, as far as the isthmus — is of
decisive significance for the further shaping of the medullii,*
and for the development of the cerebellum. The lip in the re-
gion we are considering bends well over and becomes adherent
to the lateral wtdl, tiftcr which there is a visible egress of armies
* Franklin Dextor. of Harvard, has recontly shown tliat in the rnbl)it the
rhomboiilal lip does not exist, the inorpiiolofiical changes ap|iarcntly de-
pending in tliis animal entirely npon the wandering capacities of the neuro-
blasts. Arch. f. Anat. u. Phys , Anat. Abth. (beipz.). 18i»r,. S. 42;{-4;n.
1;
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of iicurobliists (l''i{,'. 1()4) from tli(^ lip into the latiTiil iiml vciitnl
pltitos of tlic iiicdiillii, wliicli lii( iiiftliiiliy to it. As tlicy Wiiiid'T
ill, tlu'y jiass vt'iitnilly as rcgurdd tlic tractiis solitariiis and
motor iiiicUii and voii-
trally to tlio formatio
ri't icuhiris, the lattrr
in tlu' mt'antinut liav-
in<j been formed l»y
cells in the neij,'hl)or-
liood of the motor nu-
clei antl solitary tract.
.Many of them pass
medially almost as far
in tlui
as the
one
Themo-
Vui. lOJ.— Sc.'tioii tliroiiKli n iMirti.Hi of ilic> wiill cf "" ""' '/'I'
(III' ini'diillM nC a liiiiiinti iiiiliryip. (ACirr lli^. ) middle HlU!.
Niiiriililii^tsiirisliiiwii wiiiidriiiiL' iVciiii III! rlidiii- , . ,
lioiiiiil li|> inwiiril ihr iiiidilli' liiii'. Tlir iiiicliiis tor iiuch'i anil tractus
nr^n,.. i>.v|m,k1..ssm1 >u.rv,. is iMi.iKi.i.ri...i inihr ^solitarius, while re-
taining the same re-
lations to the central canal, now oi^cupy in transverse section
an entirely dilTcreiit ]»osition as regards the ventral surface of
the medullary tube. Instead of lying superlicially they are
buried in t\w depth by the crowds of neuroblasts which have
wandered in from the lateral regions. These neuroblasts ar-
range themselves so as
to form the inferior ol-
ivary nucleus and the
medml and lateral ac-
cessory olivary nuclei
(Fig. ioo), and last of
all the buryiiiLj is made
still dec])er by the nyh
pearance of the pyni-
niids, great bundles of
fibres, the last to be
nu'duUatcd in the me-
dulla, which represent
the processes of neuro-
blasts situated high up
in the pallium of the fore-brain (telencephalon), which have
grown down through the inter-brain (dience])hulon), and mid-
brain (mesencephalon), to the medulla to end at different
Kid. 105. — Scheme of one half of tlie emltryonii!
iiKMliilla at a later stajje. Tlie tir.iy masses cor-
resiiDiidinj; to tlie olivary bodies have het^n
formed, and the imcleiis of the hyjiofilossiil
nerve and Ihe traetiis solitariiis are far re-
moved from the ventral siirfaee. (After llis. )
T[IST()(iKNKTI(' IIKI.ATION'S OF TIIH NKUIIONKS. 177
Icvi'ls ill the spinal conl. Tliiis the lamcllutioii of the iikmIuIIu
ill late cmld'yonic stufjcs aii<l in tin- ncw-liorn {V\'^. 10(1) iiiurtt ho
l((nkt'il upon, as His says, us tlu' rt'sult of iin cpoclitil (h'vclop-
iiit'iil ol' wliicli tlic (lilTcrciit staj^t's an; ri'prcsrntcil \>\ the sue-
/I
SrFld
I'Ki. 1(1(1. — 'rraiisvi'i'sc section tlinxii;!) "iic Imlf of tlic ninliil
i1)liiii<'at:i III' a
hii
iiiMii I'liilirvo at llii'i'i^jitli Miciiilh.
I'lliillati
(), iilivc willi acci'ssorv cilivaiv linilii
.M'tcr Kiillikcr. ) /'. pyramid iidI yet
(l(\ tilmi' rcrcl
iilivaics; /V, ri>i|nis rcsliluriiif ; /.V, .V, N. ulcpssiiiiliaryii^clis and N. va^Ks ;
A", iiiiflciis of li rnilnaliiiii nl' siiisory porliim nl' N. vaKiis; /•'■<, tracliis suli-
lariiis; I', ti'a<'tiis spinalis N. liitri'iiiini ; A'//, N. liypuKlussiis. Its niicU'iis
iit'nri^'in is snn near tlic tlimr of tlif I'miilli vrntcii-lc, tar rcinovid I'loni llu!
ventral siirl'a<'e; /•'///., I'ascieiiliis Icinuiliidinalis ]ne(....,is; >"•', siratniii inter-
olivare K imiisci.
cessivi' ;i(l(liti(»ii of (1) the motor miclia ; (2) tlu' formatio ivtit^-
iiliiris ; (:j) tlu' oliviiry nmsscs ; (4) the pyramids. As tlioy lie,
so tlu'y have dcvi'lopcd. Tlicir position is, as it were, tli^ k(^y
to their (levelo])inental liistory.
11
17«
TIIK NKUVOL'fS SV.STKM.
I
i
i
i
* Mall. F. P. llislofjeiicsis of the Kcliim in AmblysloiiMi and Ni-i'tiiriis
J. Mdi-phol.. Bast., vol. viii (1H!);J), pj). 41.")-4:52.
I ill
/I
CIIAITKU WH.
Tin; DKVK.I.OI'MKNT OK Till", I'KKI I'll KH A I- SKNSOItY NKl'HONKS
AM) Ol' TIIK HY.MI'ATIIKTIC NKl UOXKS,
Origin of scnsf " )i;aiii,'liii. |)ori|ili('riil sensory norvn fibres, dorsal roots o(
spinal iicrvi ' and dorsal while fwniiMili of the spinal cord — 'I'lii' devel-
opment of liic rfjans of special sense — The ear — The eye — 'i'he nose —
Wanderinjrs of neurol)lasts in the fonnation of the syinpalhetic nervons
system.
WilKUKAS the ()ri;j;iii (»f tlu' motor (il)f('s of tlie pcriidicral
nerves iiiid the intrinsic intramedtilhiry fibres is to be soii^Mit in
tlie neuroblasts of the medulhiry tube, these do not fjive rise to
tlie jjenei'iil periplierul sensory nerve til)res iind the nerve fibres
of tlie oi'jfuns of special sense, nor to the fibres and cells of the
sympathetic nervous system. How, then, is the orij^in of these
to be explained ? Concerning this there has 1)een some dispute,
but the skein is beinj? f^radually disentan<,ded. From a {?iven pe-
riod of development on, one can make out near the medullary
tube on ea(di side jfroiips of cells which re])resent the bc<;innin<:s
of the sensory pinj^lia of the dorsal roots of the spiiuil nerves, so
that the cell bodies of till the sensory neurones of the first order
are situated'outside the neural tube — that is, outside the spinal
cord and brain (P'ifj. I OS).* The studies of His, Marshall, Hal-
four, Heard, von Lenhossck, and others have taujjht us wheiue
these cells are derived. All arc ajjreed that they come from
the ectoblast at the junction of the edges of the medullary
plate with the adjoiniiiff ectoblast (Fi}i:. 10!»), althoufjh there are
a number of researches which make it jirobable that a certain
number of the cells do not wander off until the medullary tube
* That in development I lie system of the sensory pin;;lia can pfrow en-
tirely independently of the presence of the mi-dullary tube, or, perhaps more
safely expressed, that the sensory paiifrlia may be present in the absence of
a sjjinal cord, is well shown bi- the case described by von lieonova, O. Ein
Fall von Anenc(>phalie combin.'rt mit totaler Amyelie. Nenrol. Centralbl.,
Leii)z., M. xii (\H9ti). S. 218; 263.
170
I
i
■I
a
i§m
i
;
,
I8i»
TIIK Ni:i{ vol's SYSTKM.
liiis hfcii piiiflicd otV t'roiii the t'ctodenii. In the front |)iirt of
tlic head, correspoiidijif^ to the sensory refjioii of tlio trif^einiiius
iiiid especi.illy to the iieoustie-fucialis area, tliere exist in Ww.
l'"l(i. KIS. — IJcciiiist ruction of iillliiiiii ciiil^-yoal ciiil ol' I'ourlli wci'k, sliowinj; dc-
vcliipnu'iil of sensory .L;aii},'li;i. ( Al'irr Mall.) I', Oasscriaii j;anf;li(iii ; .V,
\ajius ,naii.Li;liini : 1, lirsl cervical ^'aiiiilioii ; S, last cervical KaiiKlioii ; 1:.', last
llioiacic 1,'aiiKlioii. Tin- |ilireiiic iicivc is seen arising IVoiii llii' Idiiilli cervi
cal iieive.
ectoiU'riii, at points eorrespoiidiiiy; to this jiinctioii, delinite
rid<i;es which are crowded will' dividing cells very like those
that His takes to he the forcrunn.rs of the iieurohlasts in the
medullary tiihe.
In the reij'ion of tiie eai fossa these cells can often ])e seen
hea])ed up as a eoinpact eoiuinn shoved in ])etweeii the ec^to-
hlast and the nu'<lnllary tube. In the trunk, liowever, no
marked a<,'<;rejiations of <;terniinal eolls are visil)le at an early
stajro, and, aecordinfjf tt) His, the f^'anylia of the s])inal nerves in
human heiniis are fornuvl of lU'urohlasts whieli collect in j^roups
iri
IIIST()(iK\KTIC UKI.ATIONS OF TIIK NKrUONHS. Isl
after \viiii(k'riii<: out from tlic [)()rtioiis of the cctoltliist adjacent
to tho nicduUarv tuhc. Acconliiijf to others, the spinal jiun^^lia
are made up of neuroblasts wliich wander (mt from the dorsal
edjfe of the medullarv tube. Dr. Mall tells nie that in Nt'cturus
he has ohservi'd a nuinher of the <;anj,dia of the tail havinj;
their orij^in in a pinehin<,' olT of ganj^lionie nuisses from the
gaiijxlia lyinj? farther headward.
The younj; cells <:ivin<f rise t(» the nerve elements of the
spinal ^Miii^dia diviile hy kary(»kinesis even for some time after
they have arrived among the ganglionic groups. The further
developnuMit of the individual cells, thanks to the researelies of
Jlis, is now very well known. The cells assunu' a bipolar shape,
one process growing from each ])ole. 'I'he jtrocess correspond-
ing to the deinlrite (that is, the one arising on the pole of the
neuroblast, which originally was turned toward the external
surface of the end)ryo) grows toward a peripheral sensory sur-
face, the process corresponding to the axone growing central-
ward until it reaches the outer surface of the medullary tube,
into the wall of which it penetrates, bundles of these, assum-
ing in the spinal cord a longitudinal direction, go to make up
• (iaiKj/idiiii- liihle.
Kctinii'im.
A
Mediilliiiii fiUitv.
Kctiiflcnii.
(Iiiiiiiliiiuiv I iiliji'.
(■
Mll<itiiliir.
Fic. ln<». Three stages of (leveloimient in tlie early liistmy «il' the spinal Kiinylia
ol'llie limiian eiiil>ry<>. (.M'ter M. von Lenlinssck. i
the primary dorsal funiculi, in the nu'duUa, the atudogous trac-
tus solitarius, the radi.x desceiulens m-rvi vestibuli, and the
tractns spinalis nervi trigemini. The relations of tiie dorsal
roots to the spinal cord are well shown, as are those of some of
u ' n
: 1
i:
t
•
182
TllH NERVOUS SYSTEM.
the cells of the veiitnil horns, in the aecompaiiyiiifj fi<;^iire,
copied from van (iehuchten, which represents the <levelopinent
in the chick (Fig. 110). An earlier atage is well illustrated iu
t. rait. pott.
r<u- post.
Fill. 110.— 'rniiisvci-so sccticni of (lie ciiihryoiiic curd of tlic cliick. (After van
(icliticlitcn. ) c. vi\i[. init., (ills which j;iv<' rise to axolies of veiitml roots ; c,
i-<i(l. ixist.. cells which j-ive rise In the few ceiil rifii;;:il axones of dorsal roots';
(V)/., collateral (side tihrii) |)assiii;,' from axoiie of cell ol' the veiitnil horn l)a<^k
into the irray matter ; (/(/, cells of spinal <;an;;lia ; rac. pii.sl.. dorsal root tilires ;
nic. aiit.. ventral root (ihres.
■f
c i.'Kj. 111. Fm. 112.
Fk;. 111. — Bipolar cell from the spinal Kaiifrlion of the pike. ( .\fter Krdlik.'r )
11. sheath of the cell lio.ly ; /,, sheath of the nerve liltri-s ; <•, mvelin sheath ;
(/. axones ; c, cell protoplasm : n. iimdcns.
Fi(i. 11'^.— Hipolar ganglion cell from the ganglion si)inile of the iiig. ( .\fIer('orli. )
till
IIISTOdKXKTIC IJKIiATlOXS OK TIIK NKl'KOXKS.
is:
I'ig. lli {ridr sii/)r(t). The two pnxH'sses of tlio spinal gaiij^lion
4_t.'ll, ceiitnil iiiul iK'ri{)lu'nil, go off from oiu' edge of the cell,
i)eiiig at first in a direct line with one another, the nncleus
and the main mass of the cell body, as His dcscrihes them,
lying eccentric to the iii)re. This bipolar contlition is in some
animals maintained throughout life. In tlu' tish, for example,
even in adults, lu'arly all the spinal ganglion cells are bii)()lar
(Fig. Ill), and it is of no little interest to find that in human
beings, and in nuimmals generally, in the ganglion on the coch-
lear nerve (ganglion spirale, r/'. Fig. 11"^') and in the ganglion
Kic. ii;{.
Fiii. lit.
Fid. li:i.— Scliciimtii' irpro.soiitiUinii nCthc Knid":'! tniiisitiim oft lie hipoliiri'cllsof
the siiiiial KiiiiKlia to the .so-called unipolar t.vpe. ( .M'ter His. )
l''l(i. 111. — Tniiislon nation of hi polar cells into iinipolaicells in IlieCiasserian ;;an-
jilion of the pi^. (.Vt'ler van (iehuchleii.)
on the vestibular nerve (ganglion vestibuli) this primitive bi-
polar condition of the cells is iilso maintained throughout th»^
whole of life. Hut in all the other sensory gtinglia of mtin
there is a grtidual tninsformation from the bi{)olar to the uni-
polar condition, typical of the adult spinal gtinglia, recognized
and described by Ranvier more than twenty years tigo. Oecti-
Icl 1
is tl
m
I .^
/i
1
i
: (
1
i
iv
1H4
TIIK NKUVCtUH SVSTKM.
sioiiiiUy, siiifrlc ])ij)()lar cells ])ersist evi-ii in the spinal fjunglia
of the iitlult, iis recent reseiircli has sliowii. In the acconii)atiy-
I'"l(i. 11."). — l'"clt\V(irk aliiiiil spiiiiil Ki'i'Klin'i iills of tlic cat tdriiicd by divisiims of
the axoiics of "spinal ^aiiKlioii ccllh of tlic second tyix." (Afttr DokIi'I. )
.(, pciicaiisiilar plexus ; II. ('irciinicellular plexus.
in<r (lia<>rani (Fi<j. 114) the early stops in the formation of the
'J'-til)re of Kanvier are well illustrated. It is obvious that the
chaiifife consists rather in the formation of a ]»rotoplasniic pedicle
than in a gradual approximation and fusion of tiie central and
peripheral fibres, as was formerly taught. The cells in the
developing spinal ganglion of a guinea-])ig stained by van
(Jehuchten by (Jolgi's method siiow very clearly the mode of
transformation (Kig. 114). The sheath of the sjjinal ganglion
cells appears to be mesoblastic in its origin, although some
assert that it also has its origin from the ectoblast.
A few multi])olar (^ells occur also in the .spinal ganglia.
These cells, previously seen in the embryo by Disse, von I^en-
hossek, Ramon y Cajal, and Spirlas, and thought to be rare and
of little significance, are said by Dogiel to occur also in the
adult.
Dogiel has recently given an ac(M)unt * of a special hitherto
* Dogiel, A. S. I)er Hiui der Spinalfjaiifilieii bci den Siiugothleren. Vor-
liiuf. MiUheil. Anal. An/,., Jena, Bd. xii (IHWi). S. 140-152.
'J
IlISTOOENKTIC KKLATIONS OF THK NKUKOXKS. iSa
Hi
undt'Kcrilu'd variety of cell in tlic spinal <raii^iia, wliicli lit'
names " spinal ganglion ei'll of the second type." The nuiin
iixone of the cell breaks up inside the gan^dion into a large
niiiid)er of niednllated fibres, which finally lose tlu'ir medullary
sheath and terndnate within the ganglion in a fine pericellular
arborization about the spinal ganglion cells of the ordinary
wcdl-known type. The axones of the cells of his second type,
according to Dogiel, form iu)t only an extracapsular feltwork,
but also a fine intra('ai)sular feltwork about the spinal ganglion
l''l(i. IKi. — Scliciiic of the icciprdCiil iclaticms of (lie flciiitnts witliiii the s|)iiial
KiiiiKlii'ii. according I" KoKicl. .1 ami II, ventral and dinsal niiils: (', spinal
nerve; /'and /•,', venlnil and dorsil divisions of spinal nerve; /•'. ramus (ir.ii-
irninicans (synipallietie ennnecliou I ; (/. 6. s|>inal Kan;;li(pn eells id' llie liisl
and seednd type ; /(, trunk pnieesses of eells of tlie lirst type whiidi divide tn
lorm the axones 1)1' the peiiiilieral and eentnil tilu'es ; ». axones ol' cells ol' the
seeond type whit li I'ud as a perieellular I'eltwork alxiut (lie eells id' I lie lirst
typ<' ; .V, syinpathelic (Hires wliieli end as a eireumeellular plexus al>oUt the
ecdls ol' (he seeond tyjie.
cells (Fig. 11'^). The s])inal ganglion cells of Type II are, he
thinks, in turn surrounded by nerve endings from the sym-
pathetic, a finding which, if confirmed and taken in connection
ji- ll
/
J,?
? I
\f
ISO
TIIK NEIIVOUS SYS'I'KM.
with the ()l)S(>rviiti<)Ms of Klirlicli, and ('specially witli tliosc of
Riiinon y Cajal, is of cxtri'iiic si<;iiilicaiicc in ilt'aliii^' witii tli(!
functions of tlio spinul <(iinf^lia and the relations of the spinal
and synipatlietic systems to one another. 1 have re[)roduced
in '''i- ll'l Doj^iel's scdieniatic representation of his conception
of relations inside the spinal f^ani^lia.
ould take too lon<; to describe in detail tiie mode of
development of tlie orj^ans of speciul sense. It is interestinj; to
find that the develo))ment in them conforms very closely to
that »)iet with in the sensory nerves in f^eneral. .VU tiie |)cri))li-
eral neurones in the organs of sjjecial sense, as in the si)inal
C'eiltrtil }t<Ti'iiiis .Hi/::triii.
Iii'ceH»u.i lithi/iinthi.
AVrrj/.s' fiirhti'd'-
.\frrii.i ri:itil>uli
yrrriis fiaidlis
(hniijlion rentibitlare
(ianylioti i/fnicidi
(liDii/lio)! siiiralp
I)}icliis .•l)'l)lil^in^Hl(ll■i^
ItoHtiiior.
Diwtii.i .leiiiirirculiiim
Utrifiiliis
Haccnliin.
■Duct)ii cochlcaris.
!'"i(i. 117. Left jiiiditoiy Vfsiclc with the aciistico-facial (•oiiiiiltx ota liiiiuaii >'in-
lu'vii at tlif lil'tli week. After His. .Iiiiiior. I'roiii Kolliiiaim's tcxt-liciiik, .S.
o Jti, Kifj. :53;5. 1
ganglia, arise from cells of the ectohlast and pass through the
neuroblastic stage, the axis-cylinder processes of the neuro-
blasts growing into the central organs to terminate in them in
free endings. In the ear, for exiimple, the ganglia connected
with the cochlear and vestibular nerves contain cells whose two
})rocesses grow away from the ganglia, the one toward th(^
periphery (to the cochlea or to the vestibule), the other toward
the centre to the nerve tube at the juncticm of the medulla and
pons (Fig. 117). These ganglia are in every way analogous to
dorsiil-root ganglia, their only peculiarities consisting in (1) the
short distance which the peripheral process hits to go before
terminating; {'i) the maintenance throughout life of the bi-
polar condition.
Dim
Kit,,-
ilerm
...
Mrmi-
ilerm
i
('ii))in>i \
vitii'iim
ilcnn)
1
('iinii-a -
i
Ri'fiita
Sclrra utid
<'hi)rioidea
\a
niSTOC.KNHTIC UKIiATIONS OF TilK NErifONES. [sT
t
In tlic i-yc, too, all the norvi' I'li'iiioiits of tin- n-tiiiii arc of
ncuroblustic orij;iii, and tlic axoiu's of tlu- ('('lis of the ^iiiijjflioii-
(•('11 layer, <,'ro\viii<,f Imckward, pass by wiiy oi' tlu- oi)tU! iicivo
7'(7< »/<i7)/i(i/<i»i.
I>irli
<i'i>h<il()ii ri^"-
SldlL- III'
uiilifliiiliiiir
vesicle
ISonli'i- iif ()/)/i-
thuliiiif cujj.
Oroove in
Stllllc ()/
rfHirtf
Arteria
reiilralii
retiniK.
l''l<; IIM. ( >plitlialiiii(' vesicle slupwin;; stalk iiiiil jiiouve in sl;ilk finm a liiiiiiiii
eiiiiiryo of tile I'imrtli Week seen iViini lielow. Al'lei.l. Knliinann. I.elir-
laicll (ler KntwickellinKS^'eseliirlite (les Menseiien. .leiia, IHits, Kij;. :U(>, S.
i»Hl, I Tile aiteria centralis retinie lias lieen ilrawn in Iniin lindin^is in a
liUliuin eniliryn at the sixtii week.
r
J' I
A
Kilii-
lierm
Mfno- ...M..(.
ilenn
I 'iiriiu>i
vitii'um
( .U.SD-
itfvm)
Cornea
Retina ■■
Striituni
jtiijmenti
SileriKtnd
Chorioidea
l''l(i. 11!). neveli)))!!!}; eye cif Imnian eiiiliryo 1(1. 'i mm. loiij;. i After .1. KdII-
niann, Lelulmcli der KntwickeliinKSficscliiciite ilcs Mensclieii, Jena, ISi»s,
s. run, Via. :u;5. i
and of tlie optic tracts into the mid-brain and inter-brain. The
eye differs somewhat in ori,<fin from all the other sense or<jans,
in thiit the embryonic masses of neurones, making up the o])ti('
I
if
n
'\
m
I ■- W'
!: .1 .-liii!
IJSS
TIIK NKllVOUS KYSTHM.
vosiclcs from wliicli the vyvn arc fortiicd, ;ir(»\v out us liitcral
j)r()ji'cti(nis i'ntni the general iiuMliillarv tiiltc (Kij;s. IIS and
11!»). Later, however, they become practically sej)arate(l from
tli(i (central nervous system, atul the fimil o! ,anic nerve connec-
tion is snbse(|uently made }»y the growth of axones, from the
nerve cells (h'j)ositc(l at tlie periphery, Itack into the central
nervous system (KifX- 1^0).* The earliest portion of the retina
to develoji is tlie region of the fovea centralis.
The most peripheral olfactory sensory neurones (h'serve
especial mention, siiu-e in the nose we titul the only evidence in
human beings of a condition quite general in invertebrate
Fl<i. I'^O. — ('(iiiiiiositc (liiiKnmiiiiatic tnuisvcrsc section i>l' I lii' head of ii Itiiitiiui cin-
liryo to sliow tli<' Krowiiifi point in the nervous system, and tlie direction of
tile f;ro\vtii of the (ibre. }f. niednllary <'anal : /•,'. eye; (), ear; A', nose; (\
ceplialopod eye ; L. sensory cells from tlu' skin of lundn'icns. (After Mall.)
forms {(■/. researches of von Lenhossek on the central nervous
system of lumbricus, and the investigations of Retzius upon
invertebrtite forms). Tn the olftictory mucous membrane the
early stages of the neuroblasts are present among the epithelial
cells, just its in the ectobliistic ridges from which the spinal
ganglion cells arise. But instetid of these young cells wander-
ing out from the epitheliiil phite, as appears to be the case
with the cells of the spimil giinglia, in the nose they remain
* Cf. Mall, P. P. Op. cit.
IlIS'nxJKNKTlC KKI<AT[()NS OK TIIK NKUIIONKS.
I SS)
tliroiiffliout life situated in the iniu'ous ni(>iiil)raii(> itscH", tlio
axoiK's, which, by the way, iifV(U' Ijucoiiic nu'dulhitt'd, ^rowiiijj
upward and backward throujjh the crilirit'orui phdci to cuter
the olfactory bulb, where they teriniuute iu free eud-arboriza-
jsp.c
pan
umc
/
mmM^^^^
I
. 'ijt
m
t ■
..-n
Ui
l''i(i. V2\. — Tniiisvci-si' section tlmnijili tlic aiitcriov part of tlic tniiik nl' nii I'ln-
lirvK itf Scylliiiiii. (ACtcr Haltniir. ) sp. (-..spinal rord ; sp. ;/., •taunlioii nf
ilursal mot ; nr, vciitr.il rout ; ihi. (lorsal, f:)). ii., ventral liniueli of spinal
nerve; nip. jiart of nnisele plate already eonverteil iiUo iniisele ; nip. I., pari
of inusele i)late extendinj; into tlieliml); »/., nervns lalenilis ; «», aorta ; rli.
notoi'liord ; si/, ij.. syniiiallietie !;anf;lion ; rn. i'., cardinal vein ; «/, scfinietital
duct; .s7, sefiincnial tnhe ; </", duodenuin ; lip. li. junction of hepatic duel
with it; pini. rudiment of pancreas connccled with another part of dm)-
d<'niini ; iniic, opening of innhillcal canal ( vitelline duct ).
tions within the olfactory glomeruli. In tlioso neurones, there-
fore, the oidy representative of a dendrite is the hairlike distsil
end of the olfactory sense epithelial cell, ami the bodies of the
, t'
liXl
TIIK NKinors SYSTKM.
P
pmjilion ci'Hh iirc more KUix'rficially placcfl tliiiii nvv those o(
any (»tlu'r iiiaiiiiMal sense (irj^aii.
'IMie syinpatlietie nervous systcTii is that which shows in its
(levelopnienl the most marked wanderiii'.'s of the dilTerent
constituent eU'inents. Soon after the outj^rowth of the spina!
nerves toward the periphery there can be seen coming; otT from
tliem at the dorsal ed<;e of the co'lom, sliort visceral hranclies,
which run over toward the aorta {V\}i. \'i\). Tliese appear l)efore
any sympathetic ;j;an{,dia are present and correspond to the
rami communicantes. All authors agree that the ganglion
cells of the sympathetic ganglia have an origin in common
with that of the spinal ganglia, although it would appear that
Onodi'.s original view that the former were formed by a sort of
pinching off of the latter is incorrect. According to His, the
sympathetic ganglion cells are formed from unripe motile
tend
tion, s(
life, sit
Fui. 122. — l'liotoiiiicri)Kniiili liy A. (J. lldi'ii (if sci'tion tlirouKli a iicrvf in the side
of tlic liiiiiiaii toiijjiu'. Alcohol fixation — lufiiiatoxylin and cosin. Twosyni-
l>atln'tii' naiifilion ci-lls arc visible inside the nerve trnnk near ils cdfje.
elements which wander out from the spinal ganglia into the
regicms subsequently occupied by the sympathetic chain.
These wandering cells traveling in the paths of least resistance
I'll.. \Zi.
einliry(
liniKsf,'!
nerves
litrnre.
has caref
toxylin a I
.\uerbach
sels, tiie
familiar w
all of the
to thousai
origin in
berg have
ganglia Ix
the first ti
of the ner
* His, W
schr. (1. Jlfd.
von Prill lara
iniierc .Med.
iiervensysteii
Oesellscli.d. \
ctTinn^' tlie i
V. Lcyden, Ki
sdir.. licijiz..
IIISTOOKNKTIC HKIiATIOXS OF TIIK NKlUoNKS. l<»l
tend to (((licet in f:r(>u|>s, the synipiitlictic fraii^xlia ; in iiddi-
tioii. sciittcrcd aldiif; tlic syn\|iatli('tic nerve trunks tlintiijrliout
life, sin^'le <ran<,dion cells rc^iuaiii dcinonstraltk'. Any (jnc who
WlllUH
Aorta
Hulhoim iilexHH
Ainiiitlii lordis
Syiii/HitliifiiH.
Conntvling jttexus.
Atrial iili:riin.
Vm. l'S.\. Scluiiiiitic I'l'iH'csciitiitioii of tlif iicrvc plixii^ nf a liciiil nf ii liiiiiiun
t'liiliiyii afti'i' His .liiiiicir. i Frinn .1. Kuliiiiaiiii. Lilirliiiili ilrr I'litwit-kc-
hinnsKtscliichtf di's MchhIicii. .Inia, IMIIM, S. r>(K. Fiy. ;J.'{7. The ninliac
nerves fiiiiii the vm^iis iire lielieate, lliose of tlie s,viiij)allH'tie eoarse, in tiie
(it'll re.
has carefully studied oven ordinary sections stained in liaMnu-
toxylin and eosin from the heart, alimentary tract (plexuses of
Auerhach and Meissner), the tongue (FifT- l"-^-), the hlood-ves-
wels, the bladder, the sexual organs, and elsewhere, must he
familiar with these ganglion cells, and it is now believed that
all <»f them which are to be found in the viscera, amounting
to thousands, or ])erhaps millions, of elements, have had their
origin in this nomadic way. The younger His* and Rom-
berg have already worked out the mode of fornuition of the
ganglia belonging to the heart, and have thus established for
the first time a satisfsictory smatomicjal basis for the physiology
of the nerves of the heart, and a starting point whence perhaj)s
* His, Wm Jr., u. E. Ronib(>rfj. Hcitriij^t' /iir Iler/.iniiervatioii. Foil-
schc. (1. Med.. Herl.. Rd. viii (IHilO). S. ^74 ; 416. Ills. W.. .Fr. Deimuistifilioii
voii I'riipanitt'ii ii. Jlodellcii ziir Ilcrziimerviitioii. VimIiiuuII. d. Cong. f.
iiiiu'rc Med. Wiesb., ix. 1890. His. W., Jr. Die Kiitwick(>limjf dos ITcrz-
nervciisysteins boi Wirbeltliicren. Abhiindl. d. matli.-pliys. CI. d. k. siiclis.
fii'sellscii.d. Wissoiisch., Hd. xviii (IBDH). No. 1. Kor a n'(-t;iit discussion con-
cerning the innervation of the heart the reader is referred tc) the article by
V. Lcyden, Krilisrhe Hemerkuiiifcn Tiber TIcrznerven. Detitsclie ined. Wehn-
schr., Leipz., ii. iJeri., iJd. xxiv (1898) [DiscjiissionJ, \er.-Beil., S. 145-147.
r
, •
! i
1
i'
It»:i
TIIK NKIi vol's SVSTKM.
tliosc |)ii^/1iii^ cliiiicul proltlt'iiiH in coiincctioii with tliu ciiniiiK;
neuroses ni.iy l)t' lulviintajreoiisly approiielied (!''!;(. \'i'.\). It, is
true tl)iit ho far as repirtis the I'xaitt liistory of the (h-vehtp-
iiieiit ill the other viwcera, we are for the most part still pro-
foundly ignorant, and a \ast and attractive tield lies here op(tii
to I he investi^'ator.
The sympatiietic cells dilTcr in inany ways, l)oth structural
and functional, i'roin all other ;^'an^dion cells, a fact which is
not surprisinj^ when we consider the peculiarities of their
origin and of their environment. Whereas all othc^r nerve
cells tend to he a^'j;re;,'ated in larjfe cell comnnuMties, more or
less sharply separated olT from tlu' tissues in ^'etieral, those of
the sympathetic; system are much moi'c isolated, l»ein^ {fathered
to<^ether oidy in small heaps, while in many instances sin;,d(!
cells maintaiidnf,' their existence far from all their fellows are
completely isolated in the wilds of the hody tissues, ictaiidnf^
communication with the centres only hy means of tlunr non-
medullated axones. I'nder such circumstances it is perhaps
hut little wonder that these cells, like the pioneers of the huck-
woods, should present peculiarities hoth in hahitus and con-
duct.
I I
CIIAPTKR Win.
ON- TMK MKCirAVK'AL I'ACTOKS OK DKVKLOI'HKVT AM) Till".
III.MAN IIODY AS A Si;<iM KNTKI) OlOiAMSM.
Meelmiiical fiutorH <if (IcvclciiniK'nt — Tlic inncrvalinii of tlu> (liii|ilirautii —
Scj^ini'iilal ion of tlic IhmIv — Mclaiiicn's — Myotitiiu's — Nt'iiniluini's —
AiijjciiitDTiH's — S('l(>rotoint>» — Hiitcronn-n's — Doniuitoineres — Sclerozoiu's
— Part playcil liy tlio tnar^iiml veil — [{I'lalimi Ici the |ii'i>l)l('iiis of lu>-
rcility.
Iv tlu' study of the liistorical (l('Vi'l(»|)iii(Mit of the nervous
system, luccliiinicul factors, of a very siin[)li' nature, when
viewed close at hand, are continually nu't with. The results of
the hendin;^ and shapin}; of the medullary tuhe in its early
staj^es are apparently conijiarahle in many respects. His thinks,
with those wiiich occur in a siniph' ruhiier tuhe when suhjected
to similar influences. The iteriplieral nerves in their outgrowth
follow always, like hlood-vesaels in their advance, the channels
of least resistance, hi regions where there is much bending of
the body — for c\;ii:iple, in the neck and lund)ar region — the
nerv(^ trunks converges to form the well-known plexuses.* If a
bundle of nerves in its outgrowth meet with any obstacle in its
path, such as a bar of cartilage, a blood-vessel, or the wall of a
cavity, the bundle tends to divide, a portion of the fibres pass-
ing on each side of the obstruction. In this way the curious
distribution of numy peripheral nerves, entirely obscure before
these embryological studies, becomes explicable. An instructive
example of the light afforded in c(>rtain dark corners by his-
togenetio studies is to be seen in the innervation of the dia-
phragm.
Von Baer f bad pointed out that tbe diaphragm in nuini-
nuds develops at first in the neck region and that it descends
* Cf. His, W. Ucber den Aufbau imsorcs XerveiiaystiMns. Bcrl. kliu.
Wclmsclir.. IW. XXX (IKO:]). S. OnT: 990. Also in Wion. mod. Presse, 15d.
xxxiv (189:5), S. 1477: IWl. Also in Wion. mod. 151.. Pd. xvi(tS9:?),S. 48:5; 407.
f V. HaiT, K. K. I'l'luT Kntwiokolungsgcsoliichte dor Thieru' ; Poobach-
tung und Reflexion., ii, S. 220.
14 198
m
-■
{
11
Nil'
'If \
li>4
THE NKUVOrS SYSTEM.
Ijitcr. IFc sniri;i'slt'<l its cervical urij,'iii as an ('X])lanati()ii of the
wcll-kiiowii fact that it is iiuicrvalcd (in the main at h'ast) hy a
cervical nerve. Ciuliiit * and llisf reeo^nuzed the mass of tis-
sue whicli in the einhryo is
destined to K*^'^ ^'i^^^' t^*' ^ihe
diaphraj^m. Mall | hasstn<lied
the position of the diaphrajiiu
in several reconstructed hu-
man einhryos, and his re-
searches, taken to^jether with
those of I'skow •* and Ravn,||
show most clearly the shifting
of the organs and the con-
stantly changing rehitions ac-
companying the llexion and
extension of the emhryo. In
Fig. \'i\ the i)osition occupied
Cerr/cdl
hy the diaphragm at various
developmental stages is clearly
shown. The position marked
xliii corresponds closely to the
position of the diaphragm in
the adult ; while xii, xviii, xix,
ii, K(), and ix represent suc-
cessive stages' of the wander-
ing proccHo during develoj>-
ment. Wiien the phrenic nerve
grows into the diaphragm the
latter is in the cervical region,
and the distance from the
al cord to the muscle to
spii
* (^idiat. O. I>u (li'volopponipiit do la portion ('('phiilo-thoraciqiio do
l'oiiil)ryoii ; do la rorination clii diaplirajj^iiu', dcs iilovi'cs. dii poricardo, dii
pharynx el do I'li'sopliajifo. .1. do I'anat. of piiysi(d.,olo.. Par., t. xiv (1878), pp.
();iO-()74.
f Ills. \V. Anatoinio inonscIiIicluT Einbryonon. i, 1880; iii, 1885.
t ;\Iall, I'". I'. l)ovol()pinont of the Iliinian ('(oloni. .1. Morphol., Host.,
vol. xii, 1S<)(1-!»T. pp. ;i<,»r)-ir):!.
* Uskdw. N. roller dio l']nt\viokolunp <los Zworclifolls, dos Pcricardiuins
and dos Coolonis. Anli. f. niikr. .\nat., Honii. lid. xxii (I8s;5), S. 1J;')-'2I!I.
I Uavn, I']. Dio Hildiinix dos Saoptiini transvorsiiin lioiin IliilmoromliiTo.
Aroh. f. Anal. w. Pliysiol., Anal. Abtli., 'joipz. (18!)(i), .S, 157-180.
%
^
IIISTOOKNKTIC KKLATlONS OF Till": NKIK<>NKS. IJ15
be iiinervatc'd is miniiiml. With the (lescciit of thi- dia-
phraiim the i)hivnic lu-rvi' j^rows and jjoes with it, so that in
t hi- adult \vi' havi' an ah(h)iiiiiial luusck' iniuTvatt'd hy a nerve
of tho neci\. The \vori\ of His ujton the recurrent hiryn<feal
nerve, and of Nusshauni upon tiu' wanderinj:^ of luuscies and
their iniuTvation, are of inti'rest in this connection. As a nial-
te" of fact, an entirely new conception of the relations of the
riiiiseles to one aiu)tlier, and to the nerves and hoiu-s, has been
{faiued throuj^h the aiuitoiuieal studies of Huxley, (Je<jenbaur,
I'aterson, Dohrn, R. (i. Harrison, Fiirbriiif^er, Mall, Kisler, Hoik,
IvU'fe, van Wijhe, and others. Since from a inori)holo,i,Mcai
standpoint the nuisch'S are most t'aaily understood hy consider-
ing them as end organs of the motor nerves sonu' referem-e to the
ideas at present held in this connection will here he in place.
As is well known, nnin, in i-ommon with a large series of
aninuds, is a se :mentcd organism. Kven in the adult the ver-
tebral column, the roots of the spinal nerves, the ribs, and the
transverse baiuKs of connective tissue in the rectus abdonunis
muscle give evidence of this. Hut when we go beiu'ath the
surface and study the segnu'idation of the body of man and other
aniuuils in the end)ryo, and compari' the relations of adult
structures with the end)ryological mendjerment, a conception of
the amitomy of the luunan body is gained which is wholly foreign
to and impossible for the ordinary student of the old-time dis-
sectinjr room. This mend)erinent or nu'tamerism is iimst
sharply to he nuule out in the end)ryo with the apjjcarance of
the primitive segments (])niiovertehrie, metameres, or Vrscji-
nii'iilr of the (iernuins). The muscular system is originally laid
down us a series of muscle segments (myotomes or somites)
which are derived from the (h)rsal jiortion of the metameres.
The segmentation is almost as clearly visible in the nervous
system (neural segments, neuromeres, or neurotomes),* in the
* Tiicrt' is still (lispiit(^ as to tlic iiciiromorcs. 'I'lio Icriii was ap|ilic<l to
tilt' s('{j;ni('iilatioii iudicatcil by a scries of altcnialiiiir slisjlit cnlariii'imMits
ami conslrictioiis of the mi'diillarv tiilic. I'lacli I'lilarccniciit. is siipiioscd (o
('oriTspoiid to a pair of ventral nerve roots, 'i'he latter, howovor. appear to
spring from tlie eonstriclion lielween two neiirotneres, and Minol (llnnian
Kinl)ryoloj;y, |)ago 00.-)) suggests thai the ventral roots arise from half of two
adjacent frue neuromci'es. CL I'latt. .Inlia 15. Mull. Mas. ("omp. Zool., at
Harvard College, vol. xviii (IMS!)), p. 171. Loey, \V. .\. Anat. An/... Jena,
IJd. i.\ (181)4), S. 3!>a. Neal, H. V. Ihid., l?d. xii (. 18!)0). S. ;i77.
1 *'■
I,.
!;■?>:
A.
a'! J
'II
i
196
THE NERVOUS SYSTEM.
vascular system (vascular sofjinent or iutorsogniont or angei-
otonio), and in tlie skeletal system (hone sej^ments or sclero-
tomes) ; it is also to be made out probably, though much less
distinctly, in the alimentary tract (enteromeres) and in the in-
tegument (dermatomeres). The overlapping or " telescoping "
of the segments and of the segmental derivatives in general
complicates the study in human beings, but witiiout the con-
ception of segmentation anatomy can not easily be understood.
VJ
wr
h
sk
sk
cp
ch
mp
ao
vn
ao
Ih
h
uk
mes'^
Fio. lli'). "Scliomes of transverse sections of yiiunjier and older Selacliian oin-
l)r.Vi(S to illustrate tin' developineiit of tlie eliiel' jiroducts of t'le middle ter-
niinii! layer. 'After van Wi.jlie and llertwin from A. Uanlier. Lelnlineli der
Anatomic des Mcnsclien. lid. I, Leipz.. 1S!)7, S. TrZ, Fif:s. 15, l(i. i
A, transverse section tlirouKli the re^jion of the fore i<idney of an endiryo in
wliicli tiie muscle setinicnl. »»y), is ))cinj; pimiied otf.
J5, transverse section tliroUKii a somewhat older embryo in which the nniscle
sennients have heen pinciied olf. \n\ nerve tube; c//, chorda; dti. aorta; sch,
sulicliordal column ; <»/>. muscle plate of tlie primitive scfjmenl ; "■, /one of
growth by wliich the muscle plate liemls around into the skin )ilate, c/* ; vh,
^>iece unilinj; the primitive segments with the body cavity from which the
tubules of the primitive kidney, nk, develoii; sk. skeletoKcnous tissue which
iirisi's by proliferation from the medial wall of the uniting piece, rh; rii, fore
kidm'y; ntk'. ink'', iiarietal and visceral middle layer out of the walls of
which the mi'senchynu' develoiis ; Ih. liody cavity; ik, layer for intestinal
glands; h, cavity ot' the primitive sejjment ; uk. tubules of the primitive
kidney; iik, jioint of separati<in of the tubules of the primitive ki<lney from
the primitivi' se^'uient ; »</, diu't of primitive kidmy with whi(di the kidney
tubules have nuiteil on the ri>;ht siile ; tr. connection of the tulmles of the
jirimitive kidney with the bo<ly cavit.v ; iiii's'. //ic.s', meseuchynie wliich has
liad its oriniu in the parietal and visceral middle layer.
Leaving out those of the hetid, the number of which is not
yet exiictly determined, the human body has from thirty-five to
III8T0GENETIC RELATIONS OF THE NEURONES. I97
thirty-seven primitive segineiits or inetaineres on eacli side ;
eight cervical, twelve thoracic, five lumbar, live sacral, and
Myiitijiiie.
Intermediate coliinm.
,.- Ectuiiiiin,
,,.,,, , . ■* ''vWPSff* ^:.*■•^"• Wolffian riilye.
Custom - . - i'^-:':'! Sft-: »,n.atn,.h'Hr,
Si>I(in<:hiui])leure — i -^^5^
VI
Mtnibr. reuiiiens.
0^' J^ ■ ^ enii n)iihili((ili.f.
l'"i<i. I"i(i. — Iluiiian I'lnliryo fixirtt'en to sixtpi'ii days olil ; Icl't luilf of cniss section
■< "240 to sliow (l('Vil(i)iiii}; iiiyotonii'. i After .1. Kolliiiaiin, Lelirlmcli der Eiit-
\viekellllif,'sKeseliielite (les .\(eiistliell, Jena, ISitM, S. 1:5:5. !■"!«. 71.)
from live to eight caudal. The primitive segments appear in
the embryo as sharply delined masses in the mesoderm lateral
from the chorda dorsalis and the mediUlary tube. They ai)pear
one by one, gradually increasing in number as the eiid)ryo
grows, those in the cervical region being the lirst to become de-
veloped. Kach mctamcre or primitive segment is divided into
a dorsal portion and a ventral portion. The dorsal portion
gives rise, as we have seen, to the myotome. The ventral por-
tions of all the metanieres are in the craniota fused to form a
commtni cavity, the hypoc(elom, sometimes called the ventral
or unscgmente<l co'loin, which corresjunids to the body cavity
(pleura?, pericardium, peritonanim). Fig. 1"^').
The appearances on section in the human embryo are repre-
sented in Fig. 1*^(».
Each myotonu'or muscle segment is at first hollow, but later
is seen to be tilled with a core of cells, tiie so-called nucleus of
the metamere (Kemak's Vrit'irlielkcrn). These cells stream
out from the medial side of each myotome to form the sclero-
tome or skeletal segment (Fig. 1"^7), and there are accordingly
us many sclerotomes as there arc myotomes.
I
III
'
1>8
TIIK NKUV'OUS SYSTKM.
("orrosjmnding to each niotaniore there is an artery and vein
(vascuhir se^fnieiit or anfrciotoiiu"). Further, each metamere be-
hind the iicad receives the motor root and the sensory root of
one s})inal nerve. Tills s])inal nerve, inchiding hotli tlie motor
part and sensory part with its spinal ganglion, together with a
portion of the medullary tube to which it l)elongs, represents
one neural segment or neurotome.*
Til' lines which in the eniliryo se])arate the primitive seg-
ments or nietameres from one another are known as the inter-
segmental lines. In these develop later those myosepta or
myocommata which se])arate the myotomes from one another,
and in the adult give origin to the ribs and the intermuscular
septa.
The muscles of the body are divisible into (1) skeletal and
(2) visceral muscles.
The skeletal musculature, which includes the eye muscles,
the muscles of the trunk and of the cxtreniitics, arises from the
myotomes. The visceral musculature, which includes the mus-
cles of the alimentary tract and of the iilood vascular system,
* As will he pdiiitcd oul in Soclidii \'i, Ilcml lliiiiks that ti coni|mrisi)n
of liis sludifs with tliosi' of Slu'rrinjjton indicate tlmt the soj^ineiit in the
s|iin;il pord does not oxaelly correspond to tli(> ncrvd roots in its peripheral
relations.
a!U
tit
i'l
B
HIST<M}ENKTIC RELATIONS OF THE NEURONPIS. 1«J})
arises from tlie unscfjiiiented mesodenn, ospocially from its
vis('oral or splaiK^hnicr layer. There lias been some dispute as
to tlie nature of the rnus( Ics of tlie head (mus(des of the eyes,
tongue, jaws, and branehial arches), l)ut the results of nuiny
investigators make it seem prol)able that they have their origin
in atypical myotomes (ventral portions of head myotonies).
Since they arise from the cells lining the cavities of the bran-
chial arches, however, a nund)er of investigators look upon them
as belonging to the visci'ral musculature.
During development marked wanderings of the muscles
take place, and it is exceedingly interesting to attempt to trace
the relations of envh embryonic myotome to the adult mus(!U-
lature. In general it would appear that each myotome of the
trunk undergoes subdivision into a dorsal part and a ventral
part, these two portions being separated from one another
by connective tissue. The dorsal part of a myotome gives
rise to the large muscular mass which occupies the costo-
vertebral groove, Fig. 12H, A 1. The ventral part of the myo-
tome extends out into the
ventral parietes (P'ig. 128, A
2, 3, 4, 5), in the thorax, for
example, helpijig to give
rise to the intercostal mus-
cles (2), the subvertebral
muscles (3), the subcostal
muscles (4), and the mus-
cles of the upper extn^mity
(5). The ventral muscula-
ture (PMg. 128, A 2, 3, 4, 5, ''i«- 128.-Srl„>ino of bono iin.l ninsc!.' s(>k-
, ,\ " ', ., , i\u-nt. (After A. Riiiilicr. Ltlii-lMicli <I.'r
and B v.) together Wltil tlie Atmtomic dcs M.iisclicn. V Anil., I,.i|>/,.,
dorsal musinilature (Fig.
128, A 1, B (1.) make up
the parietal musculature
derived from one myotonu^
The visceral musculature!
corresf)onds to the mass
marked (<>) in the (igur-!.
The division of the parietal musculature into a dorsal jior-
tion and a ventral portion separated by a connective-tissue
septum is very much more distinct in lower vertebrates than it
is in man. The line of separation betwi^en the dorsal and
1M!(7, S. !()(), Via. IDS.)
A. - c, hixly 111' vcrliln'ii : </, iivciis vrrtcl>rn' ;
r, iirciis (■(pstiiniiii ; A', iirciis visccralis ; /,
ilorsitl purl III' iimsclc si-j;iii(iit ■. .'-'i, vcn-
Iral pint uriiHiscIc scuiiniit willi its ilill'cr-
cnt siilxlivisiciiis : .;, prcvcrlclinil ; //, siilt-
I'listiil ; .', iiitt'rc((st;il ; .1, piirtiiiii for cx-
Ircinity; C. visccrMJ iimsclc.
15. — Tlic imrictii! iiiusclc scfjniciit liniiiylit to
its siiiiplfst expression ; (/, doi'Siil p;irt ; r,
Ventral part.
200
TllK NKllVOUS SYSTEM.
ventral muscnljiture is known in these animals as the lateral
line {SeitcnJinie oi the (Jennans),* and here arc* situated an im-
portant series of sense orf;ans known as the " sense organs of
the lateral line." It is not unlikely that tlie so-called branehial
sense organs (Beard), which appear temporarily in the region
of the head in young end)ryos of higher forms, correspond to
the sense organs of the lateral line of lower animals.
Each myotome has a neurotome corresponding to it by
which it (along with the skin and other adjacent structures) is
innervated. The ventral and dorsal roots of a spinal nerve
unite to form a common trunk, the mixed nerve stem. The
latter, the pcriplicral representative of one neurotome, divides
into a dorsal ramus and a ventral ramus. The dorsal ramus iu-
Dorsal '•..
til iisele
Jwlil.
Kdiinis .
iloiisd-
tin Herri
SllilKlliS.
Hdiiiii.i
veii-
tralin
lierri
spiiutlis.
I'eiitrnl •
iiiiiiirle
fiekl.
Myoseptum.
Dorsal liinb.
Strntiiin
(lorsdtf.
l.n'al blaste-
tiiii {aki'lrlid
/)/«/<■ I.
Vfiitnil limh. Stratum vciitralf.
Fi(i. 12it. — Trunk scfjiiicnt of liiinian cinliryd witli niic iwiir cf nerves ;in(l tlie
niilinient of the iiiiiseiiliitiire of one extremity at the sixth week, seheinatie.
(After. I. Kollniailli, r.eiirtiueh (1< r lMit\viekehin},'s;;esehi(iite (K'S Mensi'lien,
Jena. IKlls. S, ^>Si), V\)r. Kit. )
nervates the dorstd portion of the myotome, the ventral ramus
the ventral portion of the myotome. Fig. 120.
At the time the union of the neurotome with the myotome
occurs, the latter is in close proximity to the medullary tube.
* Corresponding to this we have in htinmn beings the deep layer of the
fascia itimliodorsalis separating the dorsal iiiiiseuhitiire of the trunk from
the ventral.
IlISTOGEXRTir KHLATIONS OF TIIH NKrUOXKS. 0()l
and the distance t<» be traversed by the outgrowinj^ nerve is
niiiiiniiil. As development proceeds, however, the muscles
ciiangc tlu'ir position, in hirge part owing to their skeletal at-
tachments, and become farther and farther removed from the
places in which they originate. The displaced myotome deriva-
tives carry their nerve branches with tiicm ; where the muscle
goes, the nerve accompanies it. In the adult the easiest clew, as
a matter of fact, to the myotomic origin of a given muscle is its
nerve supply.
Some of the muscles of the adult body have been derived
from more than one myotome. 'IMius, those arising from two
myotomes are known as diplomeric; muscles (e. g., the supra-
spinatus and infraspinatus muscles), those from more than two
myotomes as polymeric muscles (e. g. the pectoralis major and
minor muscles). In such instances the diplomeric or polymeric
origin of a muscle is indicated in the adult by its diplomeric
or jtolymeric innervation, for muscles derived from more than
one myotome are innervated by nerves derived from the ventral
roots belonging to more than one neurotome.
The origin of the muscles of the extremities and the inner-
vation of these muscles are of especial interest. For our knowl-
edge in this connection we arc much indebted to Dohrn,* 1'.
.Mayer, f Kastner,J Paterson, * van Wijhe,|| van Hemmelen,'^
* Ddlirii. A. Studion zur I'l-ficscliichti; dcs \Virl)t'ltlu('rkr)rpers. VI. Die
pnui'ij^i'ii luul unimairn l-'losscn der Si'lacliior. .Mittlicil. mis dcr zool.
Stiitioti zu Nciipcl, Md. V (1H84). Also, Die unpaiirc Flosso in ilircr Bcdi'ii-
tung filr die lU'urllii'iliiiif^ der jifiu-alofiisclieii Stcllmifj dor Tiiiiir'aton und
des AmpliidXiis, und die Ui-stc dcr IJcckfiiHosse hei I'etromy/on. Ihid., I5d.
vi (tHH,-)).
^^ Mayer, P. Die unpaaren Flosson der Selaciiicr. Mitthcii. aus der
zodl. Station zu Xeapcl. Hii. vi (1885).
X Kiisliicr, S. Felier die allj^eineine Entwickelung der Rumpf- und
Schwanznuisculatiir bei Wirheltliicren ; niit tu'sonderer Ueriieksiclitiijfung
der Selachier. Arch. f. Anat. niid I'liys., anat. Alitlieil.. I.eipz. (1H!»2). S. \m-
'i'i'l; also I'elier die JMiIstelumjr der Fxtreniitatenniiiseulatin' l)ei den anii-
ren Ani|)liil)ien. Verliandl. tl. anat. Gesellsch., ,Iena. 1H!»!{, Bd. vii, S. 1!);{-199.
* I'aterson, A. >[. On the Fate of the :Mns(le j'late and the Develop-
ment of the Spinal Nerves and Ijind)-i'lexnses in Mirds and Mammals.
Quart. J. Mier. So.. Lond.. n. s.. vol. xxviii (1HHT-'8H). pp. l(»!»-12ft.
II van Wijhc.r.W. Ueber die l\resodermse<;inente und die Fntwiekelung
der Xerven des Selaehierkopfes. Verhandel. d. k. .\kad. v. Wetensch. .\mst.,
Deel xxii (188;{). pp. 1-;S0.
^ van Hemiuelen, J. F. Ueber die Ilerkunft der Kxtremitiiten- und
\
I
u\
I
\
h
202
THE NERVOUS SYSTEM.
KoUniiinn,* iiiid in Aiiicrica, Ryder,! ii>*<l cspeciiilly 11. (J. Iliir-
rison.J Tlu! inusoulaturt' of the cxtreinities is derived in the
FtCJ. 130. — KccKiistriictioii "f a ycmiiK liimiiiii cinlMyii <iilinj;c(l tivr times, illns-
tratiii}; the pusitioii of tlic M. rectus aliiliiiiiiiiis and its iiolviiieiie natiiie.
(Alter F. P. Mall. ,1. .Morpliol., Un.st., vol. xiv (lHi)7-'!»Ni, I'l. 1$, Vi^. 4.)
t
H
ih
Zmif^enmnskuiatiir hf' Eideohseii. Aimt. Aiiz., Jcnn. Bd. iv (1889), S.
24()-2r)r..
* Kolliiiiuiii. J. Die Rnm|)fsej.;riieiite iiieiisclilicher Kiiibryoiieii voii 13
bis 35 Urwirbehi. Arcli. f. Aimt. mid I'hys., Leipz., Aiiat. Abtheil. (I8i)l),
S. 3!)-88.
f Ryder, J. A. A rontrilmtion to the Fiinhryogfiiiihy of Osseous Fishes
with Speciiil IJefereiiee to the I)eveIo]iiiieiit of the Cod ((Jiidus niorrhiia).
Aiimiiil Report U. S. Com. of Fish and Fisheries for 1882.
I Harr' , R. (». I'eher die Kiitwiekeliiufj d(>r uicht knorj)olif; vor-
j;;el)ii(h'te kelettheih' in deti Flosseii (h'r 'reicostier. Aroh. f. Mikr. Anal..
Bonn, Bd. xiii (1893) ; also The nevelopnient of the Fins of Teleosts. The
Jolins Hopkins rniversity ("irciiiars (1894). No. Ill ; idso The Metamerism
of tiie Dorsal an' 'he \'entral Longittidiniil Muscles of |}i(> Teleo.sts. The
Johns Jlopkins I . .versity Circuhirs (1894), No. Ill ; also Die Entwickeliinp
der unpaareii uiid paarijren l''lossen der 'I'eleostier. Arch. f. tnikr. Anal.,
Bonn, Bd. xlvi (189.")), S. .WO-STS.
HISTOGKNKTIC RKI.ATIONS OF THK NHUHONKS. 2<)3
main from muscle huda which are pinched otf durinji; dcvolojv
ment from the trunk myotomes. According to Harrison, a cer-
tain number of tlie muscles of the extremities are derived from
the unsejfmeiited nu'si'iichynu) rather than from the myotomes.
It seems likely that tin; relations of myotome to neurotome
hold also for the extremities, but thus far, owing to the ex-
tremely complicated processes of development, it has been im-
— ■ ^
t
m
■
r
r
/(
^r^.ri'./J:
Fi(i. i:?i.
to till
Fields oil tlic fxtci'iiiil surface of tlie os iiiiioiuiiiatlliii corresixiiKliiiK
attiu-linient of llie \arioiis muscles. Tlie llnuiKii-luiiilio-sicral nerves
littli) Koveriiiuf; the individual muscles are indicated. (.Vfter L. Hoik,
lol. .lalirl)., Lcipz., I?d. xxi, Isid, S. :.*t^', Fiji. I.)
possible to determine this iil)solutely. Here also in the adult
structure it seems probable, however, that the neurotome supply,
i
i
K
.1.1 It
ill!
4
2(14
THK NKRVOUS SYSTKM.
when it ran bo ostiiblisliod, is a safe fjuido to follow in drawinpf
eoiu'lusioiiK as to tlic nivotoniic oriiMn of the various niiisclos.
Fid. IIW. -( )iitci' Mirfiicc cif OS iiiiiinniiiatiiin. Tlii' lines luiiiiid llic iirciis in
wliirli ari' fcmiiil tlic iitlacliniiiits dl' the nillscic masses <iei'ive(l ('mm the
mycitnuK's iiinerviited )>y tiu' l:itli to tlie llttli tlioi'iico-liimlio-sienil nerves.
The Kil'<lle zones on tiie lione hetween the lines ai<' the so-ealh'd "seiero-
zoues." (Alter L. liolii, Morpiiol. .laiirl).. Leiiiz., \V\. .\.\i, lSlt4, S. :24r), Fij,'. 2.)
That these general principles hold for the human abdominal
muscles iind their inin'rvtitiou has recently been demonstrated
by Mall,* Fig. i;5().
* IMall. F. P. r)ev('l(i|iineiit of tlie Ventral Abdominal Walls in ^laii.
J. Mdrjiliul., Bust., vol. xiv (IbUT-iib), \^\^. ^47-^0(5.
IllSTCXiKNKTIC RELATIONS OK TIIK NRUUONES. 205
An extensive series of iiive8ti}j;ati<»ns uii(lert!ii<en l)y Holi< *
must here he referred to. His results rejjiinlinj^ the innervu-
tion of the iiiusch's of the pelvis aiitl their hony iit'iaeiiiiieiits
may he ehoseii as an example. .\s will he seen hy reference to
Fig. i;U, there are successively attached to the ilium in a ven-
(J.
K
?>
"^
^
fv;
h
Fid. 1153. — Hccdiistnittcd fiiriii of pilvis nf Ihiiiimii I'li'lus, illiislviiliiij; skeletal
ureas correspiiiKliii}; til (lii^ iiiyutoines iniiei'vated l).v (he l:.'tli-litlli iliorarn-
limitio-.siicnil nerves. (.Vl'ter I., liiilk, M<ir|iliiil. .laiirli., I,ei|)/,., IM. .\.\i,
1S!I4, S. ^>.')(i, KIk. :5. I
tro-(lorsal direction the followinfj muscles: (1) M. sartorins;
(:i) M. tensor fasciie lattv ; (:5) M. glutanis minimus; (4) M.
glutajus medius, (5) M. glutivus nuiximus ; ((i) M. piriformis.
* Hi)lk, \i. Rezicluuifjon zwisclicn Skeli^t. Miiskuliitur iiml Xervcii ilcr
Extreinitiitcn, tiarp'legt am Hofkeiif^iirtel, an desseii ^Iiiskiilatiir. sowie am
Plexus lumbosacralis. Morphol. Jalirh.. 15(1. x.\i (1804), S. 241-277 ; also,
Kekonstruklion dor Sejjmcntinin,!; dor Gliodmassoniniiskulatiir, dargidojjt
an den Mnskeln I'es Obonsohonkols und des Seliultorjjiirlels. Morjihul.
Jahrb., Loipz., Hd. xxii (18n4-'9r)), S. 357-379; also, Die Sklcrozonie des Hu-
merus; zugleich oin Roitrag zur nildungsgcsoliichto dieses Skeloltlioilos.
Mor|)hol. .lahrb., Leipz.. Bd. xxiii (189.')). S. 391-411 : and Die Sogmental-
dilTerenzirung des menschliehen Kumpfes und seiner Extroniitaten. Mor-
phol. .lalirb.. Leipz., Bd. xxv, II. 4, S. 405.
irr
u
200
TIIK \KI{ vol's SYSTKM.
'I'licsc JtiiisclcH lire innervated by ti corresijoiidiii',' HcriuH of veii-
tnil roots, us is sliowii by tlie iH'('oiii|tiiiiyiiij; tiil)lu.
Tahlk 1.
SlM'illl H(M|UI'I1CI
!'' n;'li:''''.:rjn .•.'.''',,I''.r"'i'iT,.!ll''i'.','\'!!If ImH-rvUi r n,.. mius..|..h l.y tl.orac...
1. M. siirtiiriiis.
2. .M. tensor fascia' lata'.
!l. M. glula'us iiiiniiiiiis.
4. M. jjliila-us nicdius.
5. M. jihita'us maxiiiiiiH.
(i. M. |(iriforiiiis.
14 15
1« (17
1(1 17
Id 17 IM
17 IM 1<»
IH 1!)
A^'iiin,tlie follo\viii<^ muscles are siiecessivoly attjujlu'd to tlio
pubis Jiud iseiiiuin in vciitro-dorsid direetiou.
(1) M. reetus ulxioMiiiiis, \I. pectineus, M. adductor loii^nis,
M. iidductor brevis, M. gracilis, M. adductor niagnus, M. ob-
turator externus, portio is<diiadica M. addu('tori8 niagui, M.
(piadriceps fenioris with the M. gcnu'llus inferior, M. seininiem-
branosus, M. seiuitcndinosus, M. biceps feinoris, M. gemellus
superior (obturator internus). These muscles are in a similar
way iiiuorvated by a series of ventral motor roots of spinal
nerves passing in a cranio-caudal direction, as the following
table makes clear :
Tabi.k II.
Serial seciiieiuie of the imisi-Ies according
to their origin fnmi the jiuhis ami
jschhiMi 111 ventrodorsal (lirfutidii.
Innervation o
iiiK thoraeo-
r the iniiseles
liiinbo-saeral s
1.V th(
linal
• follow-
iierves.
1. .M. rcflu.s filidomiiiis.
0-12
2. M. peel incus.
14
15
;{. M. luMiiclor ioiif^ns.
14
15
4. IM. adductor brevis.
14
15
K)
5. M. gracilis.
15
HI
(5. M. add 'ignns.
15
in
7. M. o' xterims.
15
16
8. ' ulica M. adductoris
•
16
9. ,,iadricc[)s fenioris + M. gc-
nielliis inferior.
16
17
18
10. M. seniinu'niliranosus.
16
17
11. M. seinitendiiiosiis.
i
17
18
12. M. biceps feinoris.
18
19
13. M. obturator internus (gemellus
superior).
16
17
18
19
: f|
it
t'l
1I1ST(K!I«:NKTI(' IJKI.ATIONS of TIIK NIUUONKS. -jdT
Kl,i 1:M -Anai.K.'.u.nl uni... ..,.t:i/..m:.l .l..rsi,l iutv.s Inr <''<■ '"''ri'"''', «'"<"•'-
Ki(i Uir, -Arra.iKcin.'i.t ..f the ii.ctji/cniil ventral ncrvs lor tl.o Mm flcxorcs.
(Artor L. Rolk, Morplu.l. Jahrl.., L.'il./-.. 15<1. xxi, 18!t4, S. 2(il, !• .«. ;,.)
1
l:
• , il
! :
■ l.:ii i
ilill
i
"l^^S
TilK N'M It VOL'S SYSTKM.
Bolk has ai'c'onliiitfly drawn a sorit's of liiii's over tlic surface
of tlie pi'lvis corri'sixuKiin^' t<» the limits of the attacliiiioits of
tlio (iorivatives of successive myotonies. The ])osition of those
Kl<i. i:{ti. — ArniiiKiiiifiit ol' the pro/oiial ilmsil N. Iciiiniiilis. (Al'ttf I,. Hoik,
Mnrpliol. .lalirli., lid. xxi, isill. S. :.>();!. Fi";. li. )
lines corresponds to the myofommata or mesodermal septa
which in the em1)ry() separate the myotomes from one ujiother.
It seems likely that the distribution of one myotonu' stands in
a detiuite relation to that of a jfiven sclerotome. The surface
of the bone givinj; attachment to the muscles deriveil from a
giveii myotome is known as a sclerozone. in I'^if^s. l.'il and V.Vi
the various sclerozoni's on the outer surface of the pelvis are
demonstrated. It will be noticed that the muscles attached
to the ventral surface of the pelvis have been derived from
myotomes more anteriorly placed, while those attached to the
dorsal part of the pelvis have orijjinated in myotomes more
caudally situated.
That the relations are much more simple in the embryo is
not 8urprisin<;, and Hoik lias done anjitoiny an important ser-
vice in pointing this out. In Figs. 133 to 138 the tVetal
IIISTCHJKNKTIC UKLATIONS OF TIIH XErUOXKS. 2(>9
conditions ari' illustratrd. Tlu* scU'rozonos at this ju'riod ari-
limited by straight lines. The Itone is nuich sinii)lt'r in form,
tiio complexity of the later relations of the museles and nerves
l)einj; in larjjfe ])art diu- to skeletal alterations. For a descrip-
tion of the { I) prozonal, ("J) diazonal, and (:>) metazonal nerve
trunks* ((1) N. femoralis, (v*) N. ohtnratorins and (;5) X.
ischiadieus, Nn. {jjliitu'i and N. obturatorius internus) and the
metOianical factors which have led to the curious distributions
of muscles and lu'rves in the adult, the ori<^iiial article of liolk
may be consulted. An e.xcelleiit epitome of portions of the re-
/
^••»
Fk;. 137. — Ari'iiiiKciiiciit n'" tlic diii/niuil vi'iilr;il N. iiiiHirntoriiis. (After L.
Udlk, Miirpli'l. ,)Mlirl>., liil. xxi, isitl, S, -Mri. \'\fi. 7.)
search is givon in the hist edition of Rauber's Text-book of
Anatomy.f
The s(derozonic anatomy of the humerus is indicated in
Figs. V.V.) to U'-.*. Bolk believes that the mesenchyme out of
* Noincticliitiirc of Max Fi'irhviiifriT.
•f Haiil)or, .\. Lt'lirl -luli dor Aualoinie des Jleiisclieii. \'. Aull., Leiiiz.
(IbliH). B(l. ii, S. 5<)0 ir.
15
.flJ
210
THK NKRVOUS SYSTKM.
f
r ^01
f^
uli
w
i'
\<<
which thiit nortion of the .skeleton which corresponds to a
Bclerozone is formed arises from the same segment as tlie myo-
mere belonging to tlie sclerozone, hut will not assert that the
whole mesenchyme undergoes segmentation — that is, that a defi-
nite metatnerism of its whole substance can be (k^nionstrated.
It appears that the humerus is formed of the mesenchyme
corresponding to tiie fifth, sixtii, seveiitii, and eighth cervical
myomeres. It is a curious circumstance that of the muscles of
the humerus in the proximal part of the bone, all are derived
from tile dorsal layer of the musculature, noiu' from the ventral
{(/. stratum dorsale and stratum vcntrale in Fig. \'i\)). The
only nuisclo of ventral origin at the proximal end of the hu-
Fi(i. 1H.H. — Arriiiificini'iif iirtlic vcnfnil and dorsil |)i'iizonal, diazonal. and nicta-
zonal norvfs. lAftvr L. Hoik, Murpliol. .lalirh., Hd. xxi, 1H!»1, S. ^'(iti, Ki^. 8. >
merus is the long head of the biceps, which comes from the
stratum ventrale derived from the fifth and sixth (cervical myo-
meres. Even this is not connected with the ventral surface of
IT
VUi. l.J!).
«'ll( l(.V(
<>/' (Ik
|)i>si(i(iii
Morjili,!
merus, tli
sections o
luture, cv(
'•"id that
firrangeiiK
140 to \A-i
Tile ni(
concerned
to be thoi;
IIISTOOKXKTIC UHLATIONS OF THE NEURONES. 211
the axial hlastoina, but lies instead in tlu- bicipital fjjroove (sul-
cus int('rtubci'cularis),a fa(!t which Molk looks upon as evidence
that the ventral mass of the axial blastema has in this reirion
not been (lilTereiitiate(l. Dctspite the fact that the sclerozones
lonjfitudinally considered take a tortuous course down the hu-
i )
/
Fi(i. ll?il. — Six transverse seetiinis llinniKli a rinlit upper arm, /- 17, at tlie (lirttT-
ciil levels indicated in the iiPUfjitiidinal view of tlie ininienis. TIk^ relation
(iC tlie ((larl<) ventrnplaniuii to the (eoliirh'ss) diirsoplanuni. as well as tlie.
IMtsitidli nl' the t (i eervieal sclerozones, are illustrated. (Alter L. Molk,
Morphol, .lahrh.. Leipz., Hd. xxiii, 1S!I.^), S. 401, Fit;, -l.)
merus, tliey are reciprocally regularly iirranfjed, its the cross
sections of Fij;. 1:5!) show. Tliat the ventral and dorsal niuscu-
liiture, even in the adidt, form two sharply separtible j^roups,
iind that in each of these groups the primitive segmental
arriingement is discoveriible, will be clear from a study of Figs.
UO to IX-i.
The most wonderful, however, of all the mechjinical factors
concerned in tlie development of the nervous system would Beem
to be those which, according to the ingenious liypotheses of
■
t ■
r ■
Mi
•' i '■
*«••■••* '
t
4
U
212
THH NKUVOrS SYSTEM.
f ;•
llis, are connected with the niarf^inal veil. It is almost like a
fairy tale to be told that the direction of many millions of
white fibres within tlie central lu-rvous system diirin<,f dcvelop-
nu'iit (lei)ends upon simple obstructions otlVred at the i)ro})er
time and in the right degree to the outgrowing processes of
the neurobhists. We have seen the long distances which
certain of the axones have to travel from their cells of origin
in order to reach the cell bodies and dendrites of tlie other
neurones which they have to influence, some of the axones of
the fibres of the pyramidal tract, for instance, having to extend
!«
FUi. 140. — 'rniiisvcrsf scctidU tlinmKli tlu' iiiusciihitiirc nt' tlic sliiiiildcriiiHl clifst.
Tlu' liiavy (lark lini' indicates the limit l)cl\vi(ii v<iitial and dorsal deriva-
tives of tlic iiiyoincrcs. The (itlier lilies show the liinils of the piodiiets of
the Ith-Hth ii'i'viici-tliofaeie iiivomeres. (After L. Molk, Morjihol. .lahrh.,
Leip/., lid. x.viii, IS!),"), S. K)S. Fi^. 10.)
from the gyri centrales to the lumbar region of the spinal cord.
We have idso noted the manifold metamorphoses passed through
in some loctilities at several periods of develoi)ment. And when
one recidls these distances and complications, even when less-
ened and simplified by looking through the large end of the
telescope of eml)ryology, it seems almost inconceivable that
mechanicid factors alone should so direct the iidierent activi-
ties of the growing tissues as to ultimately give rise to tidult
inSTOCiKNHTlC RELATIONS OF TIIK NP^URONHS. -Jlii
striu'tures wliicli, wlu'ii cxuniiiu'd with hifjli powers of tho
microst'opt' in tiio conTspoiidiiig parts in two clilfercnt imli-
Fi(i. Itl. — Transverse section thr(iii};li tlie i)ri(xinial ixirtion of the liunierus.
lAfter li. Hoik, (ip. ,if.. \'i^. 11. •
viduals, arc scarcely distinguisliablc Especially dunibt'ounding
is it to be told that the same developmental factors hold in the
convolutions of the cerebrum ; in that portion of man's nervous
Fl(i. 142. — Tr.iiisverse section tliroufili tlie distal i)art of tjie liunienis. (".Vfter L.
Hoik, i>i>. rit.. Via. 12. 1
system wliicli we believe to be functionally concenu'd in his
mental processes ; and particularly when we reflect that both
M
214
THE NERVOUS SYSTEM.
:|'i
¥
f.
^\
k
^
the bodily and montiil i liiiractoristics of the individual are
lioreditiirily transmissible. As His lincly puts it (tiio trans-
lation is free) : " It is exactly in these last considerations that
the key for the correct understanding of the special relations
is to be souj^ht. Like every other orfjjanic foi-niation process,
the ori<i;in of one's body and of its nervous system appears
as the expression of a life process in course of pro<;ress {iin
G((H(j hcfntdlirlicn /A'/jciispro'cx.s). The bcffinning of the pro-
cess we do not know, for since time immemorial it has been
striding forward, periodically producing new individuals ami
again destroying them. Each individual life is oidy a partici-
pating member of the life of its generation series, comparable
to a single one of the waves resulting from the propagation of
one wave over wide surfaces of the sea. Advancing from one
member to another, the life of the generation passes through
phases of the greatest simplicity in order to elevate itself again
to summits of the greatest total energy. In those phases of
the transference of life from member to member, the mass serv-
ing as the bearer of it sinks to a minimum. An imponderable
amount of material sullices to carry over the life in a strictly
regular way. And while life is a jwriodical process there is an
all-pervading law which commands all its component processes
and their internal coniu>ction. In such a mechanism one pro-
cess goes over into another ; each appears at a given time as a
definite sequence of processes which have gone before, and at
the same time as the necessary determinant of ])rocesses which
shall come after. And even where processes of apparently dif-
ferent origin and significance reciprocally influence one another,
yet they all act at the place assigned to them by the general
law, and do no nu)re and no less than is ordered."
It is now necessary to hasten on to the consideration of the
neurone as the unit in physiological and pathological processes.
THE
The fell
met
.S|||,]
of fi
Foii
Pathol.
nial aj)
in itsel
belief tl
to any ^
the brai
ring an
bears w
of a lar
upon a
organisn
to one }
special
other pa
led to a
ogy, was
the nerv(
tiiiu' vcr
sort of V
* Viivh
l<),i,MScllC III
440, 8vo, Ji(
'.Ui, .
SE(^T[()\ V.
THE NEURONE AS THE UNIT IN PHYSIOLOGICAL AND
PATTIOLOGTCAL PROCESSES.
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CHAITKR XIX.
INTUODl'C TOUY.
The coll (lootrine and tlio iiitvous system — I'hysiolofjy of tho neuroiios — The
iiit'tal)olisin ami nutrition of ni'iiron(!s — I'MTih-I of altoration in blood
supply — The food stuffs and I'xerotory products of neurones — Constancy
of function despite continual cliunj,'e.
P\)UTY years have passed since Vircliow, in his Cellular
Pathology,* gave expression to the conviction that every ani-
mal appears as a sum of vitiil units, each of which exhihits
in itself all the characteristics belonfjing to life. It was his
belief that the character and the unity of life are referable not
to any single locality of a higher organization — for example, to
the brain of man — but rather to the definite constantly recur-
ring arrangement {Einrirlihi)i(i) which every single element
bears within itself. According to this view, the composition
of a liirger body, of the so-called individual, always depends
upon :i social arrangement ; it represents, in fact, a social
organism, in which there is a mass of single existences related
to one another in such a way that every element litis its own
special tictivity, and each, even when incited to activity by
other parts, does its woi'k of itself. AVhile this concept, which
led to a revolution in the prevailing ideas regarding pathol-
ogy, was accepted for the body in general, its applictition to
the nervous system, and especiidly to the brain, was for a long
time very little emphasized and only recognized in a vague
sort of way. And indeed this can hardly be matter of sur-
* Virohow. H. Die Cellularpatholoj^ie in ihrer Begriindung auf physio-
logische un{i pathologische Gewcbelehre. Zwanzig Vorlesungen., xvi, pp.
440, 8vo, Berl., 1858.
315
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THE NERVOUS SYSTEM.
prise Avhon we consider the enidencss of kjiowledfje at tlmt
time of the structures coueenied. Mut with th(( estiihlisliineiit
of the neurone eouei'|)l uf tiie nervous system tlu' iinportjinee
and applieal)ility of such a view of its constituent or<i;uns can
be more fully appreciated. Only after it had been clearly shown
that the nervous system, like all other tissues, consists of ele-
ments more or less isolated and inile])cndcnt, and connected
directly with one another apparently only by contact, con-
crescence, or protoplasmic bridges, and after we had learned to
recognize the different structures which belong to the single
elements, could the study of the functional units in the nervous
system be satisfactorily approached.
An extensive series of physiological and pathological data
concerning nerve cells and nerve fibres has been accumulated.
Many of these data appear to be discordant or even actually
contradictory. It will be of interest to consider briefly how
some of them appear when regarded from our new visual angle,
and to see in how far the new doctrine has brought into agree-
ment results which were formerly adduced on both sides in
support of contlicting views.
In a systematic description of the physiology of the neu-
rones it would be necessary to consider not only the functions
which they possess in common with all cells, including such
fundamental phenomena as those of metabolism and reproduc-
tion, but also those which are peculiar to neurones in general
and to neurones in particular. The facts already collected
bearing on these points, if adequately discussed, would demand
the space of a volume of considerable size, although they repre-
sent but an infinitesimal amount of knowledge compared with
that which is still needed to explain all the complicated mani-
festations of the various parts of the nervous mechanism of
mammals. I shall bring forward at this time only a few of the
physiological and pathological considerations which seem to be
of especial importance in relation to the morphological charac-
teristics previously outlined. It will be most convenient to
divide these into three classes: (1) Those bearing upon the
metabolism of the neurones, (2) tliose concerning the phenom-
ena of irritability as manifested by the neurones, and (;J) those
referring to the interdependence of the trophic function and
the manifestations of irritability. From a discussion of these
it will be found that the physiological independence of the
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THE NEUHONK AS THE L'NIT.
217
neurone is as marked a feature as nii{f|it luive been expected
from our kiio\vle(l<j;e of its inoqtliolo*,'}-.
7'he Mctahdlistii and yulrifion of Kenrutirs. — To tlie study
of the nutritive processes in neurones or their nietaholisni —
anaholic and cataholic — attaclies a hi<^h (h'^ree of interest,
althou^^h the subject is attended with ^reat ditticulties. Like
all other cells of the body, the liviuff neuroiu's take up food
materials into their substance, transform them, and f^radually
l)uild them up throujih a series of synthetic pi . esses into
hif^hly complex and extremely labile chemical compounds,
which, in turn, under<j:o a series of decomposition reactions
which culminate finally in the formation of more or less simple
i)odies, which we recognize as tlie excretory i)r./ducts of neurone
metabolism. There is every reason to believe that in these
various modifications of chemical materials by means of which
the potential energy of the food is transformed into the kinetic
energy which gives rise to what are called the " vital " mani-
festations of the neurones, chemical compounds come into
existeiu'c, in some of the neurones at least, of a degree of com-
plexity scarcely approached elsewhere on this planet, and before
the nature of which the most advanced organic chemist stands
utterly powerless and despondent. It is in the nervous system
of all parts of the human body that the delicacy and complex-
ity of the chemistry of metabolism are most in evidence. It is
there that we find the best examples of the extreme instability
of the "living" substances, in that the slightest influence will
often suffice to bring about remarkable transformations and
extensive functional manifestati(ms in ^he cells. To quote
from IMlueger : " What infinitesimally small active forces acting
in i\ ray of light call forth the most powerful effects in tlie
retina and in the brain ! How entirely minimal are the active
forces of the nerves ; what wonderfully minute quantities of cer-
tain poisons suffice to completely destroy a large living animal ! "
The dependence of the neurones upon nutritive influences
is well shown in certain circulatory disturbances. When the
nutrition of the brain falls below a certain minimum the
mental capacities become clouded or may even vanish. In
fainting, we have the proof that without an adequate su])])ly of
oxygenated blood complete consciousness can not be maintained
even for a second. The blood supply to the nervous system is
extremely well provided for by the circulatory apparatus of the
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THK NERVOUS SYSTKM.
hniiii iiiul spinal cord, tliou{]jh there would appeiir to be a grave
impcrt'cctioii in the arniuffenient of the arterial system which
tenninatcs in tiie so-calle<l end arteries, so that the hh)ckin«i; of
a sin<,di! one leads inevitably to the death of the territory sup-
plied by it.
As to the nature of the substances which represent the raw
food stuffs of the neurones, we have as yet hut littU' detlnite
information. Wiiile ultimately tiie substances taken up as food
stuff by the neurones must be derived from the general food
ingested by the individual, this must uiuloubtedly have UTuler-
goiu? most nuirked alterations before being presented to the
nerve cells in tiie blood and lymph as material suitable for
their sustenance. There is considerable evidence that some of
the material at least must have already played a })art in the
metabolism of other organs, and, in a sense, as their excreta
have first l)een rendered suitable for usi' by the nerve cells.
The physiological law formulated so long ago, accredited to
Treviranus, is probably as true for the nervous system as for
the other organs of the body. A possible exam])le of this is
seen in the thyreoid metabolism ; in the absence of substances
in the body derived from the thyreoid gland, the nervous sys-
tem undergoes very important and serious nu'tabolic modifica-
tions evidenced by the remarkal)le nervous and mental phenom-
ena with which all are now familiar. On restoring these
substances to the body by the administration of a thyreoid
extract the symptoms may sometimes be made to disappear.*
It is likely, however, that the neurones find their staple foods
in the main nutritive constituents of the blood as derived from
the food digested in the stomach and intestines and purified by
the lymph glands aiul liver. That the stainable substance of
Xissl may represent deutoplasm — the contents of the larders of
the nerve cell — is not at all improbable, inasmuch as Jleldf and
Macallum have pointed out that they yield the reactions char-
acteristic of the nueleo-albumins.
* This assumption does not, oi" covirse, exchide the possibility that the
rohition of the thyreoid to the nervous system may consist in the destruction
or neutralization by the products of the former of a substance or series of
.substances which are inimical to the latter. In any evem the disturl)an('i's
in the neurones must be thoujjfht of as metal)olic in character.
f This writer terms them the " rolling stock " {Betriebsmaterial) of the
nerve cells.
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TIIK NKrUONK AS THE UNIT.
211)
There can he hut litth- (h)iiht that the ijidividiial neurones
select from the hlood or lymph (|uantitie.s and varieties of food
stuffs correspond iiif? to their individual needs, and it is still
more certain that the constructive nietaholisin in one neuroiu'
or set of lunirones varies from that in anotlier within certain
limits whicli, though perhaps usually narrow, in sonu^ instances
must he tolerahly wide. Failinj,' thi.s, it would he im])ossil)le to
understaiul, even with varyinfj correlations, the ditferent func-
tional manifestations of which the individual neurones and
{groups of neurones in different parts of the nervous system are
capahle.
One striking feature in neurone metaholisni is particularly
to he noted. With chemical processes ever in j)rogress, with
syntheses and decojnposition reactions going on all the time,
the one set of reactions jjredominating perhaps at one moment,
the second at another, hoth classes of changes occrurring now
with great rapidity and again with comparative slowness, hut
in any (iase always continuously — with all this "perpetual tlux "
— a certain constancy of structure and function is maintained.
The hest evidence, perhaps, of this jjhysiological (ujnstancy,
notwithstanding (lontinual change {/hnirr iiti WrrJisc/), is to he
found in the consideration of the phenomena of nienu)ry. We
now know that when certain cells are destroyed hy disease or
removed hy the knife of the surgeon, the capacity for calling
up certain nuMuory i)ictures is lost. Certain })sy('hical elenu>nts
or constituents which had faded from consciousness, hut could
he reinstated hy secondary suggestion hefore the cells were
destroyed or removed, can afterward he no longer revived.
This fact would almost justify us in helieving that the " mem-
ory traces " are in some way or another laid down in the
neurones, and are actually organically connected with them.
These neurones with which the memory traces are in some way
associated are continuously uiulergoing the metaholic changes,
such as have just been described, and the wonder is not that we
have such poor memories, but that they are as good as we find
them to be. Far from being surprised that the reproduction
of past experiences in consciousness is occasionally unfaithful,
we can only wonder how it can rea(di the degree of accuu'acy
with which we are familiar.
While emphasizing the maintenance of a certain constancy
of function, and consequently of structure, despite the unend-
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THE NEItVOUS SYSTEM.
iiij; clicinical altcnitioiis jjoin^ <m, we iiaist admit tliat tlio
int'taliolisin in no individual is pcrl't'ctly fnnstant. 'I'liis is
shown ill the first place, should illiistrati(»n of what is so olt-
vioiis he d('iiiaii(h-d, under iionnal eonditioiis in the ^'radiial
iiK-reiiHc and development of the faculties of the nervous system
in early and middle life, and in their ;,'ra(hial decay as the end
is approacdied. A^^ain, takin;,' memory once more for an ex-
ample, it is prolmhie that no ''eproductioii of past experience is
aiisolutely accurate, nor is the attempt to recall one and tlie
same experience on two ditTerent occasions attended hy the aj)-
jiearance in eonscioiisness of exactly the same mental picture.
Kven when the focal constituents in consciousness- are almost
or precisely the same, the murfjinal 8ettiii<,' of so-called "suh-
coiiscioiis" elements may be at the two times entirely ditrereiit.
There is always more or less variation, tlie ditTerences l)einff
often, perhaps, scarcely recoffiiizahle, hut none the less existiii<,'.*
A whole array of evidence could he broiijjht forward deiiion-
strutiiif,' functional alterations dependent upon disturbances of
* This idea hud not its birth with inudurn physiolugists, for did not the
wise Diotiina of Mantiiu'ii tell it lonj; ago to Socrates f Let me quote from
The Syiiii)()siiiiii of IMalo (Jowett's translutioii) :
'• For even ill tiie same iiidividinil there is suecessioii and not iilisoiuto
unity; a man is called the same : ImiI yet in the short interval which elapses
between youth and afjc, and in which every animal is said to have life iind
idi^ntity. he is undergoing a perpetual procH'ss of loss and reparation — hair,
flesh, bones, blood, and Mie whole body arc always changing. And this is
true not only of the body but also of the soul, whose habits, temjiers, opin-
ions, desires, pleasures. |)ains. fears, never remain the same in any one of
us, but are always coining and going. And what is yet more surprising is,
that this is also true of knowledge: and not only does knowledge in general
come and go, so that in this respect we are never the same, but particular
knowledge also experiences a like change. For what is implied in the word
'recollection' but the departure of knowledge, which is ever being forgotten,
and is reiujwed and preserved by recollection, appearing to be the same
although in reality new, according to that law of succession by which all
mortal things are preserved, not by absolute sameness of existence, but by
substitution, the old worn-out mortality leaving another new and similar one
behiiul — unlike the immortal in this, which is always the sanu' and not
anotlier. And in this way, Socrates, the; mortal body, or mortal anything,
partakes of immortality; i)Ut the immortal in another way. .Alarvel not.
then, at the love which all men have of their ofTs|)ring, for that universal
love anil interest is for the sake of immortality." The germ of the idea is
also recognizable in the speculations of llei'aclitus, and possibly in those of
Anaximander.
THE XKIUONK AS TIIK I'MT.
221
iiciiruiif iiii'tuholism tliroii^'li (Icprivutiuii of niitriniciit, tin*
action of t()xi(; a^i'iits, uiid other patliolo^icul iiitlii(>iici>s. Miit
even ill tlu'se ul)iioriiial states it is tlu* eoiistaiicv ol' tiie fiiiKs
tidii wliicli impresses us iiinst ; the faet that, ;:iveii a nervous
system iiia<h' up of a eertuin set of iieiiroiies, the activities iii-
iiereiit in thtMii must necessarily h-ail to the manifestations «»f
certain delinite functional clmraeteristics, the alterations capa-
hle of occurrinj^ under changes of environment,* internal and
external, normal and patholoj^ical, heiiij: compressed within
certain rather narrow limits, limits which j,m'ow more and more
restricted apparently with the increuae of tliu iige of the indi-
vi<lual.t
The astronomer, supplied with certain (hita concernin<;; the
speed and direction of a f^iveii planet controlled in its motion
liy the attraction of definite forces, can predict with precision
the position it will occupy at a {^iveii moment in the future.
The hotanist, informed of the species to which a ji;iven vege-
tahle orjranism l)elon<fs, can foretell with tolerahle accuracy
what its heliavior will he under <,'iven conditions of soil an<l
climate. Were it permissihle to introduce here an opinion, I
should not hesitate to say tliat I am convinced that the hiws
underlyiii},' neurone metaholism J are just as fixed and constant
as are those of astronomy and botany, and that I can conceive
of a knowledj^e of their nature and action which would eiiahle
one possessed of it to prophesy unerriiifjjly of the functional mani-
festations of a nervous system made up of a given set of neu-
rones which must result upon exposure to a given environment.
* In this connection the articles of Dricsch, Hcrbst, and Lncb upon the
etiect of environinont upon dcvelopincnt may he rcml will; profit. External
stimuli can anil un(loui>te(lly ilo exercise an impnrtaiU influence iijion ile-
vi'lopmeiit. i)iit the character of the resjionse is dete/mined by the inherited
organization.
f If the conviction expressed in the text be well founded, then, broadly
speakiuf,', (IS /(/,s ni'Hfdin'H arf. ko //if nuin in. In this sense, (ioethe's words,
in the mouth of Mophistopheles, can be made to bear a new and almost jiro-
phetic sif^iuficaiicc :
"Dii bist am Hnde — was Du hist.
Sctz Dir Perriicken auf von Millionen liockcn,
Set/, Deinen I''nss auf elleidiolie Socken,
Du bleilist (loch immer, was Du liist."
X The same remark has already l)een nuide regarding sociology in Social
Rights and Duties, by Leslie Stephen.
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222
TIIK NERVOUS SYSTKM.
That the noiirologist is ulniost infinitely distant from any ap-
proximation to su(th astronomical accuracy witli regard to the
nervous system it is needless to remark. That he may never
attain to such omniscience is altogether probable. But the
fact that he lias already learned that in the nervous system
certain causes are followed by certain definite effects almost
with mathenuitical accuracy should encourage and stimulate
him to further research with the hope that the intricate laws
in question may gradually be rendered less obscure and vague.
CIIArTKK \X.
ON TIIK DKOEXF.RATIOK AM) UIXJENEKATIOX OK NEURONES.
("Iiaiigcs which oc-cur in a jiai'l scvoretl from thi' rest of the iiciiroiii' — Wal-
Icriaii (h'goiienitioii — Tiirciv's degonenit'on — KITot't on tiip wiioli' neu-
rone of injury to one or nioro jiarts of it — ("haiigcs foHowinir amputations
— Kx]icrini('nts of v. (Muhlcn, l''ort'l. and otiicrs — Apiilication of method
of >[archi to tlie study of the central stump of a divided nerve — Studies
of Nissl on changes in the cell bodies of neurones after section of their
axonos — Klfects of injuries to dendrites — StiKJies of Warrington and
others — Kffeols of injuries to the cell bodies of 1 lie neurones — Changes
in lumbar cord after ligation of abdominal aorta^l']x|)erimental pro-
duction of secondary degenerations — ^'alue of the metiiod of Marchi
and the method of Nissl for pathological studies — The neurone as a
whole a frophii' unit — Regeneration of nerve fil)res anil nerve cells.
As ri'<,'!ir(ls the trophic rchitioiis of the neurones, it may
witliout further preanihle be asked (1) How far is the nutri-
tion of tlie individual portions of a neurone aifected by an
interruption of their conneetion Avitli the rest of the neurone?
(2) How far, if at all, does the whole neurone suffer as a result
of injury to any one of these individual constituents? In
iittemptinj; to reply to l)oth these (piestious it will be found
that we possess data to draw upon which rejjard not all, but
certain only of the individual portions of the neurone. We
shall find, too, that an answer to one question must from the
nature of thinjrs include ii re])ly to the other. That the formu-
lation of the two (|uesti()ns as just adopted is not superfluous
will readily be fxranted, in that the c()iiteini)lati(ni of the subject
from the two different standpoints will help us nuiterially in
umlerstaudiuf? the reciproctil relations which recent research
has (lenu)nstrated to exist.
As long ago as IS;}*.), Nasse * ami Valentin f had jn'oved that
* Nnsse. Ueber die \'eriinderungen der Xervenfasern inicii ihrer Durch-
sehneiilung. Arch. f. Anat.. Thysiol. u. wissensch. Me<l.. !{erl. (1H;J!»). S. 4()."").
f Valentin, (i. De functionilius nervorum cerebralium et nervi sym-
paliiici. libri (puittuor. -Ito. Ueriia'. ls:!i».
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THE NERVOUS SYSTEM.
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interruption of the connection of peripheral nerves with the
central nervous system could lead to their degeneration. Their
findings were confirmed by Staii-
nius.* AValler f made a thor-
ough study of tlie .sul)j('('t and
formulated thefujidamental law
of the physiology and pathology
of the nervous system known
by his name. By Wallerian de-
generation we understand the
changes which take place in the
distal end of a periplieral nerve
after it has been cut through.
The details are familiar to every
medical student, the coagula-
tive breaking up of the myelin
sheath, the dissolution of the
axis cylinder, the neurilemma
with its nuclei remaining fen*
some time at least preserved
(Fig. 143). "Waller proved that
if a motor nerve was severed
there resulted complete degen-
eration of the fibres in the ju'ri-
plieral end, even to the muscles
whicli they govern, the central
end remaining ap})arently in-
tact. As a matter of fact, the
changes characteristic of ^Val-
lerian degeneration could not,
//l^(l^(ll)s (il iiivcliii ; II, I'fiiiiiiiis of
axoiif; ir. i)i(iiitVnitiiif; .ells of as a rule, be traced farther m
iicnrilcinnia. I'iirtly s<li('niiitif. 4-i,„ ^r,.,f»...1 ^,w1 fl,..,, 4^r> 4^1w> «« .*^
(Ait.r ThoiMM. A T.xt-Mnok of tlic central end tlnm to the first
Tilt lioiofi.v and Patliolofiicai Aiiat- node of Kauvicr. If a sensory
oiiiy, vol. 1, p. 50.5, l-Xii.'MH.) . • , ',
nerve is cui t'^'-ough peripheral
to a spinal ganglion there ensues complete degeneration of the
sensory fibres as far as tlic sensory surfaces in which they
* Stiiniiius. riitcrsucliuiif^cii Uber Miiskeliviztmrkeit. Areh. f. AiiaL,
Pliysiol. 11. wisseiisL'li. Med, Berl. (1847), S. 44:i-46'J.
\ Waller, A. Experiments on the Sectidii i>f tlie (il(issopli!ivyiij;:e(il and
Hypoglossal Nerves of the i-'rog. ami < Hiservations of the Alleralions pro-
duced thereby in the Stnielure of their Primitive Fibres. London, Edin-
Fl(J. 14:?. — Wallerian defieiieratioii of
nerve lilirts afttr section. /, nor-
mal iK'rve tilirc ; // and ///, lilires
slio\vin>; ditferent decrees of (h'fieii-
eration ; >'. neurilemma ; iii, medul-
lary slieatli ; .1. axone; k. nucleus
of neurilemma cell : /., markinnof
Laiilermann ; A', noclc of Kanvier;
3
TIIK XHrUOXF, AS TIIK UNIT.
225
ho^jfin.* It was further .shown l)v siiiiilar oxpcrimouts that if tho
dorsal root of a spinal iicrvt' was cut throu<j:h at a })oint hctwccu
the ganglion and tlie spinal cord, the jjortion of the nerve at-
tached to the ganglion did not undergo the typical degenera-
tion, while the portion still connected with the cord showed the
characteristic degenerative i)henoniena, which could he traced
throughout tile whole course of its constituent lil)res in tlie
dorsal funiculi of the cord. The cells of the spinal ganglia have
therefore been looked upon as trophic centres for the perijdieral
sensory nerves and their intramedullary continuations. Tins
explanation was much siniplilied l>y tiie work of His, who demon-
strated that the axone of the peripheral sensory tihre, the spinal
ganglion cell, and the axone of the nerve tibre of the dorsal
funiculus all represented parts of one and the same cell.
These degenerations in the domain of the peripheral nervous
system were eai'ly shown to occur also within the confines of
the central nervous system, the secondary descending degenera-
tion of the i)yraniidal tract established by Tiirck f and the as-
cending secondary degeneration in the spinal cord after trans-
verse lesion being (|uite analogous. We now know that the
axis cylinders of the dorsal root iibres, with the exception of
the few centrifugal fibres present in them, are axones of neu-
rones whose cell bodies are situated within the spiled ganglia.
We know that the axones of the motor peripheral nerves arise
from the cell bodies of neurones situated within the ventral
Imrgli, and Dulilin Philosophical Mnfrazinc. vol. xxxvii. Xo, 247, j). G."). .Inly,
1850. Also in Philosopliical Transactions of the Royal Society of Loinlon.
law, p. 42.]. and in tlio IMinh. M. and S. .T.. vol. Ixxvi (lS.')t). ].p. ;!(ii)-;!T(i._
Sur la ri'produt'tion di's norfs ct .snr la striioture et les fonctions dos jran-
jrlions s|)inanx. Arch. f. Anat., Physiol, u. wisscnsch. Med., licrl. (18.12). S.
;i!l'^-4()I; Conipt. rond. hchd. di's st'anccs do I'Acad. d(>s sc. Par., t. xxxiv,
p. 675. — Nouvelli! mothodc po\w lY'tude du systoino ncrvonx applicahle a
rinvi'stii;atioii dc la distribution anatoiniquc dcs cordons ncrvcnx. pt an
diagnostic des maladies du systctnc tHM'vonx. pendant la vie ct apres la mort.
Conipt. rend, helid. des swuipcs de TAcad. des se.. Par., t. xxxiii, 1851. p. G()6.
— Experience sur les sections <les nerfset les alleivitions. ("oinpt. rond. Soc.
de hiol.. Par.. 2ine s.. t. iii (I8.")7). jip. G-8.
* 'Phis appears to hold even for the sensory ner'.es connected with elab-
orate end organs, sneli as Meissner's cor[ius('les. although for a time these
were thought to lie exempt
t Tllivk, liudwig. Uebi r secnndiire Krkrankung ein/elner Rilekeninarks-
.st range und ihrer l-'ortset/u.igeii ziini (iehirne. Ztsehr. d. k.-k. Oesellsch. d.
Aerzle y.u Wieii. (IHrt'-l), ii, ."ill ; I8.j;j, ii, 'iHK.
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THE NERVOUS SYSTEM.
horns of the spinal cord, and that tlie axis cylinders of the
fibres of the pyramidal tract are axoncs whose cells of orijjin
are situated in the cerebral cortex, ("onvertin^f, then, tiie
VVallerian doctrine into terms of the neurone concept, the fol-
lowinr gener.d law may be laid down : Whenever it has sutTcrcd
a solution of con-
tinuity with a sever-
in*; of its connec-
tion with the cell
body and dendrites
of the neu'one to
which it helon<rs,
the axone, together
with the myelin
sheath covering it,
undergoes in the
part distal to tlie
lesion acute and
complete degenera-
tion.
#^Evl.G.
This degen-
Fi<;. Ml. — Section stiiincd l>y Wcifjcrt'siiu'tluKl tlinnif.'li
the cervical cord of n woiiiiiii, showing; secolidary
degenerations t'ollowin;; coin]pr(Ssion of tlic cord at
the level of tlie second tlioracic se^Miient. (After
S. {{osenlieini. ) /•'. ij.. I'aseiculns fjnieilis; /•'. ils..
fasciculus cereUellosiiinalisi direct cirelicllar tract I :
/•". c.s. /., fas<'iculi: i cerchrosiiinalis lateralis ( lateral j." • i i
l.yrainidal trad ) : /•'. rl. (1.. fasciculus vent rolaleralis PHltlOn includes not
(iow.rsi. Since the (il.res iu the fasciculus Kra.ilis „nly the maluaxone,
and many ol those 111 the lasciclilns cerehellospiualls '' _ '
and in (iowers's tract dejiencrale upward from the but also its tcmii-
site of lesion, cells of origin of the defieni'rated 1 i. ii • i.\
tihresmust he situated below the level of the second nalS, tOgCtllCr With
th,uaeic ,s, -nu.ut. The Rvranii.lal tract is not de- ^hc collaterals and
fielU'rated ; the cells whuh jjive origin t<i lis axones
are situated ahove the lesion. In tlw liKlire the de- tlicip tcmiillills COll-
UC'liorated areas are lifiht, the normal areas dark. , -, .,, ., j,
nectcd with it.*
There has gradually developed, therefore, a general belief that
what are called the " nerve cells " represent tr()i)hic centres for
the nerve fibres in general.
The appliciition of the Widlerian doctrine has aided im-
mensely in unniveling the c()m])lictited relations existing inside
the central nervous system. Thus, in a transverse lesion of
the cord, for the btinds of fibres whicli degcncnite in sections
above the site of the injury (Fig. 144), the "-(rophic centres"
i. e., their cells (of origin) arc to be sought below this level, and,
viri' verxa, the cells of origin for tracts which degenerate in
sections below the level of injury (Fig. 145) must be situated
somewhere above this level.
* Studies (if liep'Tieralioii nf the s|iiniil cord will coiiviiice any one of tho
afcuracy of this slateineiit rcf^ardiiif; the collaterals.
1^-
THE NEURONE AS THE UNIT.
221
Since the t'me of Waller iiiid Ti'irck the histolo^'y of the
(legoneration nerve fihres after separation from their cells
of origin has been studied by many — notaldy by liaiivier,*
Homen, f Howell and Iluher, and Tooth. J The last, in the
interesting tiulstonian Leetures for 188'J, has reviewed suc-
cinetly the facts up to that date. The studies of vou Not-
thaft ** are of especial value, in that they have yielded definite
information concerning the state of the nerve fibres at various
periods after the lesion. This investigator divides the changes
which occur in a nerve
after section into two
stages. The first stage
includes those which DC ^^ t— •-- - vubibbv ' aKMSf*
cur during the first three #f lill ■'^^mSsKi^ ) «l^i^CS.l.
days. These alterations, r I
wliich consist in frag- '
mentation of the myelin
and of the axone in the
first one or two inter-
nodes on each side of tlie
lesion, are, Notthaft be-
lieves, the direct result
of the trauma. The true
Wallerian degeneration
(or the second stage) be-
gins on the second or
third day in the fibre
distal to the lesion, and is the result of severance of connection
with the central cjid, and not the direct result of the trauma.
The axone swells and fragments, and the myelin breaks up into
* IJiuivicr, li. Lemons ssur I'histologic du systume nervcux, Paris, 1878.
f Hoim'n, K. A. Exporiiiu'iiti'llcr Hciti'ii}; ziir Palliolofjii' iind jiatliolo-
gisehcn Aiiiitotnie dcs Hiickonniarks (specicll iiiit llinsicht aiif die sccun-
dare Degeneration). Fortschr. d. :Med.. Beri.. Rd. ill (1885), S. 267-276;
riiiitribiition expi'rimcntale i\ la patlmlogie ot A I'anatdniie jtatlioiogiipU' de
la moolle ('>[iiniere. llclsingfors (1885), pp. 112. 7 pi., 8v(>.
J Tooth, Ho\vard H. The Gulstonian Lecturps on Seeondnry Degener-
ations of the Sf)inal Cord. Tiondon, •!. and A. ("hunhill (1880), pp. 1-71 :
also in Urit. M. .1.. Lond. (1880), i. 75:5: 825: S7;i.
•Notthaft, A. V, Nene rntprsncliiing(Mi iilier den \'erlauf d(>r Degener-
ations- und Hegenerali(ins])roc«'ssc am vcriet/teM |)ei'iph('ren N'erven. Ztschr.
f. wissenseh. Zool., lid. Iv (180^}), S. i;)-l-188.
Fi(!. 11."). — Scctidu stained l).v Wcificrt's nictluid
tiii'(iii;;li the luiiilKir curd of a woman. sIkiw-
inj; scccindiiry (IcKcni'iatinns rolldwiiiK cnin-
lircssicin ol' the cm^l at the level of tlie second
tlionicic segment. i Al'ter S. Ivosenlieini. )
Fascicidns cereUmsiiinalis lateralis ( /•'. ex. I.)
is (h'frene rated. The cells of ori;,'iii ol' its
axoiies are situated ahiive the lesion (in the
cerehral cortex).
II c:„„
,1...
//
I
TTKi
.a»m
i
i
!tl
1
i
r
22S
TIIK XHUVors SYSTEM.
droplets iiloiitr tlio wliolc length of the ncrvo. .Miiltipliciitioii of
tliL' iiiU'lt'i of tlie lU'urik'iimiji is i-vidciit iit tlu' fourth diiv. At
the sixth or seventh day liqiiofiictioii of tiu' inyoliii comim'nct's,
jiiid this continues until the sixtieth or eightieth day, l>y which
time all the myelin lias hecn liquefied aiul a lar^c part of it has
heen ahsorhed. After three or four months the myelin has
entirely disappeared.
During the secondary degeneration of tlu' wliite iil)res
within the central nervous system there is a proliferation of
the neuroglia. The multiplication of the neuroglia cells hegins
in the white matter, according to Ceni,* some forty-live or fifty
days after the lesion. The neuroglia cells cease to multii)ly at
about the humlredth day, after which there is a gradual disap-
l)earance of neuroglia nuclei with gradually progressing scle-
rotic change.
Owing to the shortness of the dendrites (unless we look
upon the peripheral sensory fihre as a dendrite), we possess no
exact studies concerning their fate when severed from the cell
bodies of the jieurones to which they belong, but we have every
reason to l)elieve that they would undergo speedy ami complete
degeneration.
Viewing now the question from the other side, let us ex-
amine and see in how far the injury to one portion affects the
nutrition of the whole of the rest of the neurone. The study
of portions of the nervous systems from individuals who had
died a certain length of time after amputation of an extremity
soon afforded data which apparently stood in direct contra-
diction to the doctrine of the trophic centres as formulated by
Waller. For, while Waller demonstrated the cojuph'te degen-
eration of the })ortion of the nerve hl)re disconnected with the
trophic centre, he maintained the integrity of that portion of
the fibre left in connection with it. f
♦Ceiii, C. Sur los fines alleration.s liistoloj^iqiies de la inoelle i'pini6rt'
duns li's tk'gt'nt'rcsoonoos st'condaiivs asccndantes ut ilcsci'iiilanti's. [ Abstr.]
Arch. ital. de bio!., Turin, t. xxvi (18!t(>-'!)T). pp. 97-111 ; also in Areh. per le
se. nied., xx, Torino (1806). i)p. iai-i!M.
f Tliis seemed to accord well with tiie well-known fact that some of the
sensory nerves proximal to the lesion are capable oi functioninjj for some
time after amputation, producing sensations which often may jjive rise to no
little mental disturbance and alarm on the |iart of the patient, since irrita-
tion occurring in the course of a sensory nerve fil)re is attriliuted in con-
sciousness to stimulation of the sensorv surface from which it has ijeen in
(I
TIIK NEI'UOXK AS TlIK I'XIT.
'2'2!>
As I'iirly iis l.S'ilt Mcnird * had noticed tliat in tlu- spinal
ncrvt's snpplyini; a lind) ain|tutati'(l sonic time before, there was
at antopsy distinct atrophy of the ventral roots. N'ldpian,
Cruveilhier, llayeni and (lilhert, Dickinson, Friedlaender and
Ivrause, Honioii, \'anlair, (irij^'oriefl", and many otluT investi-
{jators busied themselves with the subject, and came to conclu-
sions which were often at variance owin<;, as has been shown l»y
Marinesc(),t to the fact tluit the authors studied and described
ditt'ereiit phases of the alterations. Marinesco convinced him-
self that after amputation of a limb, or after section of a pe-
ripheral nerve, there occur in the central jmrt definite patho-
logical changes, the intensity of which (le]>ends upon the
species, and especially ui)on the age of the animal and upon
the length of time intervening between the injury and death.
The younger the individual at the time of the amputation and
the longer the time elapsing between the operation and. death,
the more marked are tlu' alterations. The degeneration in the
central stump of the divided nerve, although it appears Jiiuch
later than that in the distal portion, presents similar morpho-
logical appearances and is apparently an analogous process,
although — and herein lies the vulnerable point of the Wallerian
doctrine — the central end still maintains its continuity with
the " trophic centre." Not only do the sensory fibres distal
from the spinal ganglia degenerate, but after a time large
numbers of fibres in the dorsal roots proximal to the ganglia
and their corresponding fibres with their collaterals and ter-
thc lial)it of conducting impulses. The superstition referred to in the
old play —
"Still in his dead hand clinched remain the strings
That thrill his father's heart — e'en as the limb
Lopped off and laid in grave, retains, they tell us,
Strange commerce with the nnitilated stump
Whose nerves are twinging still in maimed existence" —
is not yet obsolete, as any one familiar with many of the rural districts of
this country can testify. S. Weir Mitchell has given an interesting account of
some of the sensations described as coming from the lost limbs in his mono-
graph. Injuries of Nerves, and their Consequences, 8vo, Philadelphia. 1872.
* Herard. liull. Soc. anat. de Par., (piatri^me annee, Bulletin No. 3, mai,
1829. dcuxifeme edition (184fi), p. 54.
t Jbirinesco, (1. Ueber Veriinderungen der Nerven und des Riicketunarks
nach Amputationen ; ein Heitrag zur Nerventrophik. Neurol. Centralbl,,
Leipz.. Ikl. xi (18!I2). S. 463 ; 50")'; 504.
l.
A
ii;}o
TIIK NKHAors SYS'I'KM.
miiiitls ill tilt' (lorsiil rimiciili of t lie cord niHlor/^o piilliolotjiciil
('li:inj,M's iuul lotiillv ilisii|)|it'!ii\ 'I'lic iiudor iild'cs of the cciilriil
stniiip ^r.-xliiiillv tiiiniiiisli in iniiiilx'r; in sonic iiistnnccs t li*'v
iippciir to vaiiisli iiliiiost totallv, :intl a liir^M> niinilicr of tlut
motor cells of the ventral horns dwindle in size (l•'i},^ I HI), and
Fl<;. nil. " Sccliiiii llircni^li liuniMn s|iiii;il iurd in llic niiin'v llmi'Miir rrf;ii>n nIkiw
iiiK iiii\rUr(l iitnipliv of li^lil li;ilt' dl' ((inl I'dllnwinn luiipiilaliiiii nl' i'i^;lil miiii.
I Aflor (i. MMiincscii. Niiiicl. « VnlinlM.. I.ciii/., Mil. \i i ISltL' . S. .'WHi, V\fi. l.i
Till' vciiIimI lioni is csin'cinlly Ml ruiiliii'd. as is also tlu' rasciciiliis ciiiK'aliis in
all its paiis. Tlii' rascicnliis gracilis * r' is itilait. 'I'lic atrnpli.v of (I14' cells
ill fjrniips (I anil h is vrry rviilriil.
may after a time be actually lost. The spinal jrani^lion cells do
not show gross alterations for some lime after iiotli periplienil
or distal libres have degenerated ( l-'riedliindcr and Kranse,
Homeii, N'anlair, Marim^sco). a linding which (h'liotcs that their
tro|)hic mechanisms ditfer in some way from those which are
eoneerned in the nutrition of the cells of the ventral horns. I
have thought that this may depend upon the j)ossession liy the
spinal ganglion cells of a cellular capsule.* It would he inter-
* Another point to l>i' n'moniliorod 111 I'xpiaiiiiiijr tin- ililTiTi'iici' in cfTcrt
of ilivision upon tlio poriplioral motor ami si'iisorv ihtvi-s is tlu' faot (lial, if
I'lirri'iit iiti'iis of oomiiii'tioii are eovrei't. on sort ion of a motor tiliri'. it is ))i'r-
liivps tho (lischnr^o of impulses wliieli is prevonteil, whiii? in tlie case of I In-
sensory tihro it is at first tlie reeeption of impulses wliicli is interfered witli.
h must not bo forgotten, liowover. tliat even when a pcripiu'ral sensory
■f
TIIK NKIKONK AS 'I'lIK INIT.
281
i'stiiig to note if llir synipiillict ic ;,'im;f|ioii (m-IIh, which arc iiIho
<'iM'ii|>siilalf<l, jit'l similiirly iiiid prcscrvf Iht'i?' f^rosH iiit<';xi"il.V
iil'lrr si'ctioii ul' the iicrvc liltrcs l)clniij,Mii}^ Id tliciii. I rclVr, of
course, to ^r(»HS iiitcj^rit y iihuic, iniisimich as there is iiiiieh
evich'lice, sdliie di" very recent <lnte, rnuii wiiieh we are eom-
pelleil to Itelieve that the tider struct tire of the nerve cell is
always altered hy the cuttin^i throii^^h of its axone. Aeconj-
in«; to the researches of Uiedl (/'///r iti/ni), cut tin;; of a
splanchnic nerve euusuH holh cellulipetal and eellulifu^^al
ile^jeneration.
A series of investi^^alions associated with the names of von
(Judden,* l"'or<'l, Mayser, Mendel, Mre<^tnan, Darkschewitsch,
\issl, and l'"lalan must now he considered. The first four in-
vesti^^ators experimented hy tcarinj,' spinal or cerehral nerves
away from their coniU!cti()ii8 witii the central nervous system,
especially in ncwhorn or very yonn;:; animals. These animals
were allowed to live for several months, after which they were
killed and the central |)ortion of the nerve involved, to^i^et her
with the ;jroMp of nerve <'ells (U)rrespondin;; to it, was Htudie(|
microscopically. The histolo;j;ical exaininiition revealed marked
chunjj;cs in the nucleus of ori;j:in. The cells present showed
distinct atrophic alterations and many of them had entirely
vanished, so that enutnerations (tf tho cells of the f^roups con-
cerned revealed a decided discrepancy in the counts on tlie two
sides. 'I'he nerve tiitrcs in the central portion of the nerve had
sutTered d(?;;enerativo changes, Jiiany of them having totally dis-
appeared.
Ih'cgman, in Viemia,f and I)arkschowits<!li,J in Koshew-
nikow's lai)oratory at Moscow, undertook tlu> study of the
central stump of motor nerves soon after the ostahliHlirnent of
C
^ 11/
m /{
I
iicrvo liiis hci'ii iMil liiriiiij;li, tlio corfcspdiKliii;; cells in llic s|iiiiiii f^iiiitcliii
miiy yt'l itoriiiips rccfivr some I'ciitripi'liii iinptil.sos fnnii tlii' visci-ru lliroii^ii
tlif niini I'oiiiiiiiiiiicaiiles.
* (iiuldcn, K. von. Ocsainineilc unit iiintcrlHssciif Al>inin<llun;;«in. Iler-
(Uistjt'j^olit'n von 11. (Jriislicv, Wicslxidcn, IHHil.
f Mri'^nmu. 1'-. l'cl)i'r ('.xijcriinnntciii' iiiifsttM^jciiilf Dcjjcncnition niotor-
iscliiT iMitl sonsihlcr IlirnncrviMi. Arb. a. <1. Inst. f. Anal. uinl I'hysioi. dos
('cntralncrvtMisyst. a. d. Wii'n I'niv., lHi)2, S. TH. Also in .lalirli. f. I'sychiat.,
lioip/.. 11. Wifti. M. xi (1 «!•!>-'!);{), S. T:M»7.
X Darksciicwitscli. L. IJoImt die N'criiiiderinif^on in dem cfMitraleii
Absdhnitt ciiics niotorisclicii Nt'rv<>n Ihm Vcrlctzinifi dtvs pcriplitinsii At>
schnittes. Nourol. ('.■iitralbl., Leipz., M. .\i (lH!t2),.S, 6r)8-G«8.
I,
ill
I
I
i .
;
I
I
lli^
.';{'j
TIIK NKHVors SVSTKM.
the lesion, iiiitl were iildc to sIkiw liy I lu' dfliciitc iiicIImkI of
Miii'clii lliiit t'Xlt'iisivc midoiililcd (l(';;('ii('riitiv(' iiroccsscs oc-
curred ill tiic lil»rcs.* Ill one ciise, in wliicli llie Tjicinl nerve
had been operated upon, Hrejiinan demonstrated eonii)leto
dejieneratioii of the fibres of tlie central stump at the
twentieth day (Figs. l-tT Jind 148). f Startling as were these re-
* I am not sun' hut that tliese results ('(iint' witliiii the prnviiicc of trau-
matic ilof^oiu'i'ation, in wliicli cvi-iit they woulii not contradii't llic Wallcrian
<ioi'triiu'. Ci'i'tainlv. insiiU' tlic spinal conl, jirossurt' cause', no siu'li rajiid
dogonoriition in the proximal cmls of injured filires extendiiif^ to their cells
of oriifin.
t That there is no lack of interest at present upon this topic is shown hy
the fact that, at the mcetinyof the Hritish Medical Association held in IHittj,
Flominj; reported the results of his resciirches made in Mnnk's lahoratory in
Herliii. I'f. Fleming. H. A. Ascending Degeneration in Peripheral Nerves
and the Resulting t'iianges in Nerve Cells. Lancet, London (18',)(>), vol. ii.
f !
i! I
IS '•■
TIIK NKriJdNK AS 'I'llK INIT.
0«><>
suits in fiicc dl" tlic \'in\ thai the li'(i|iliic doi-iriiu' ol' Wnllcr
li:i(l lirlil swiiy l'<»i" I'diMy yi'iii's, tlicy were t'(li|is('(| liy ot hers,
\vlii<li iimsl now lie consitlcrcil. NissI, witli his tnrthvh'iic-
lilii('-iin<l-s(iii|) stiiiiiin;^' ol' iih'ohol tissiu's, t'oiind lh:it he coiihl
jicliially (li'Uionstnilt' tlcliiiitc iilfcnitions within the nerve cells
very soon iifter the solution ol' continuity of their axones. In
ral)l>its, for cNaniple, after excision of a port ion of t he facial nervc!
on uni- siiU', ehiUiU'leristic alterations can he denionst rated, eon-
sistinj; in tlie main of a rarefaction and finely granular change
in tiie Nissl bodies of the cells of the seventh nucleus.* He as-
No. 7, ]i. SOH. — Some Xotcs on Ascciiditifj Dof^eiicrntioii (sd-callcd) ami on
the Cliaiif^fs in Nerve ("ells ('oiisc(|iifiit Thereon. IJrit. M. .1., liond. (IBlKi),
ii, ]ip. 91M-itCl. — Aseemlinj; De^'eneratioii in Mixed Nerves; a ("ritical
Sketch with Kxperimental Results. KdinI)., M. .1. (1H!)7). n. s.. i. pp. 40-60.
* " Darin, dass dieselbon unter einer feinkiirnigen Umwamlhing rare-
ticiren."
<: ^ 1
/I
I !■
Mi
m
)iM
TIIK NKUVOl'S SYSTKM.
HiTlH llitil while I lie clnmjrcs iirc most miii'Kfd iT llit> iiiiiruiil^
iin' killcil jil'irr I'nmi ci^'lil In lil'lt'cn tliivw. to one iiciiiiiiinti'il
witli llicin iihcriil'ons iirc n'cof,Mii/.iil»lt' williin tin- fclls of (liiM
iMK'lt'Us (IS I'jirit as t wi'iit v-fonr lioiirH after the t>|MM'a(i<m. Tlu'
rnnliiij,'s, as iiii},'lil Itc ('Xpcrtcil, vary f<»f llii' dilTcreiil roniis of
i\(M'V(> (M>lls and soinewluil in tlie saiix' form of eells in animals
of ililTcrriit s|t(>(ics. l-^en if llif |tcri|tlu'ral nerve is not cnt
tliron;;!) I)iit is rendered temporarily ineapalde of fnnetioniii^,
the re;iressive alterations «'un he made to appear,ns NissI asserts
he hasshown, hv the applieation (d' ehemieal snhstanees (for e\-
:i?nple, common sail) to the Iniidv of the I'arial Merv(>, or hy ap-
ply inir a temporary lij^atni-e to it.
Afl(
er these Inive reaehed u
maximum (eighteen to twenty-two to thirty days) the appear-
ances for a t ime do not alter materially, hnl NissI thinks t hat
later the majority of the cells, perhaps tliron^di the formation
(d" other nnions, heo;in slowly to recover, so that hy (he liftieth
or sixtieth day it may l)e dillicult for the inexperieneed to dis-
tinirnish I hem from entirelv heallliv eell,^'
('hariieteristi(^
ehanires in the neiirojilia accompany those fonml ii\ theiu'rve
<'ells. Of th«' importance of this nu'thod, which has heen desiij-
nated hy NissI as />ir Mrtlimlr i/rr /iriiiKiiiii l\ri:i(tiil* 1 have
already sptdxcn in another place. f The method is a very deli-
i-ate one — -in fact, the nH)st sensitive as yet introdneed. NissI
cantii>ns against drawini:; eonclnsions from its ap|tlicat ion he-
fore one has hecome skilled in the iK'cessary techni<|ue. In
order to obtain resnits of any value the operations mnst ht> done
asei>tieally. and a lon^ and intimate ac(|naintanee with the ap-
pearances presented hy tlie ditTerent varieties of cells occnrrinjj^
normally in the reijions nndtM' ■'xainination is ahsolntely es-
sential. The procedure has aln>ady heen applied to determine
a nnnd)er of complicated relations exist injj within the lu'rve
eontres and is full of proniis(> as rejjards the solution of numy
intricate tpiestions, ann)nji wliitdi NissI r(>fers with especial
hopefulness t<i thos(> involved in the study of the eye-mus(de
nuclei.
* NissI. l'\ I'l'licr iMii(> iii'iic rnliTsiichuiiirsniothuilt' des Ci'iitnilorpin
spoi'ioll ziir l"'('stst(>lliin); lior l.oi'alisatioii dcr NtTvciizi^llni. Vortrji!
fjolmlton l>(>i dor Voisainmlmi!; <lt
ihvcsl. Ni'uroldf^cii mill Irrciitirzlc
Uadon-Kiidoii, W. .Iniii 1S!)4. ("onlrallil. fiir Ncrvt'iili. iiml INycliiiit., ('uhkMiz
w. l,.'ipz.. .hili (ISltn. IM. xvii. S. H.'tT.
\ .lolnis llDpkiiis Hojipital HuUelin. vi (18i)5), p. I(i0.
TIIM N'KI'UONM AS TIIK UNIT.
285
l*'liiliiii,* ill \\ iildcycr's luhonitory, I'XiiMiiiutil the hraiii-i of
fiiiir yoiiti^' cutH, ill wliicli tlirtliinl iitrvi- liail lii'cii ciil iiitni-
( riiiiiiilly l»y (Jiid, tliirlrcii, cliHrii, I liicr, iiml two diiyH n'H|M'r-
livtly lifter Kfctiuii. Mis ilcsrriitlioii of I In- liii<liiij,'H iicconlH
I'lilin-ly with Lliow of N'irtHrrt iiiV(«Ht,i;3fiilii)iirt ( l''iK- '••')• "•''"'
l''lii. I III. (Vlls rnitii tln' iiiiilci (if 111!' iMiiliiiniplciiiiis iicivcm of llic enl I liiiti'iii
(lliys ill'lir scclioll III' till' liml liliri'> nl' llir lliivr nil iilir ^iilr Al'lrr I'",.
[•■Ii'ilnn. Kiirlsilif. <l. Mnl., Mill., Itil. xiv. iHim, 'I'lil'. i, l''i«N. :» iiiiil I. i <(, ii II
ri'iilll nilrlrlis III' siilr mil niirriiliil ll|iiili. hliiiwini: lyiiinil slirliiirlirnliii' iir-
I'MllKrinrlil ■it'Ni.sl liiiilirs ; 'i, nil rrmii iiiirlrlis nl' siilr ii|irl'Mlril il|iiili. 'i'lir
liiiiiiiiKiliiiiils ilii^^tlikr ii|ipriiriiinr is ii'iircsriilcil. Ilirr iiiiil t lirir siiiulc
liHHi'i' iin'Kiihir NissI iKidics iiic vi.sililc. Tlii' iiiicIcii.h is (lispliii'i'il In Ilir siili-
nrilirri'll.
stiites lliat lie luis (Miiployt'd tlu* iiictliod iiiiil foiiiid it to lio
useful, csiMMiiilly wlicri) tlio ccntnil n-hilioiis lire very (m)Iii|)I('x.
Siidovsky's rcscandu's f lire also coiilirinatory of Nissl's studies.
IWhotli Nissl's method and Mandii's method IJiedl J has (h'lii-
oiist rated Miat celhilipetal as well as eelhilifiigal defeneration
occurs after section of the s|)liiii(diiii(! nerve. |{(M"nli(4mer **
* I''iiilaii, !"'. Kiiiif;!' I?('tnirliliinf;('ii IHiiTilic Nciinmcnli'lirc iiii Aiiscliliiss
nil frnli/.('ili>;t'. cxiicriinciilcll fiv.ciiRle Vcriiiidfrunf^iUi dt-r Zcllcii lics Ociilo-
Miotoiiiisli.'nis. Forlschr. d. Mod.. MitI., \M. xiv (IHild), No. 6, S. 2()l-22r).
+ Saiiiivsky, S. Nrvritc (•xprTiiiinitiilt' piir conipn'ssioii (^1 h'-simis (;on-
sc'ciitivfs (ics ('cnlri's iiervoux. Ciiiiipt. rciiil. Soe. dc iiiol., I'ar. (INillj), 10. s.,
t. iii, pp. 855-358.
X i^iciil, A. l^'ticr ihe ("entni licr Splancluuc!!. Wicii. I<liii. Wcliiisclir.,
IJd. viii (18il5). S. illT) !)li).
*• Hcrnlii'imor. S. /iir Kcniiliiiss iIit liDcalisation iin Kcriij^t'liicto di's
Oeidomolorius. Vorl. Millli. Wicn. kliii. VVcluisclir., ix (lH!»t5), No. 5. Also,
f:
n
.1:
11
i
|i
'2:W>
TIIK \i:i;\()lS SVSTKM.
thinks 111' liiis liccii ;il)lc liy tliis mctlKiil to decide jis to tlie ])or-
tioiis oi" I he iiuch'ns of t he oeidoiiiotoriiis respectively coiicei'iied
^- ' ^'^afe:.!6!v.-.ii!.,i :^--' ■■■■■•
■.\
^^'"-"oi^i^k^'^'
"■*"'-',"':\
y
A
Fl(i. 150. — Four iicrvc cells f'nuii tlif iiiicliiis iicrvi t'aciulis (if ii nililiit tit'tccii days
iit'tcr sciti III of tlic III rvf itmt. Dr.iwiiif; iiiaiU' Iripiii tiiic nl' ,1. Kilaufitr's
prcparatiiitis.
in the innervation of the extrinsic and intrinsic muscles of the
eyeball. According; to him, in the rahhit the four external eye
muscles supplied by the oculomotorius nerve are governed by
the t;an<flion cells of the distal atid middle tiiirds of the nucleus
(cliiefly of the ojjposite side), while the cells of orij^in for the
intrinsic muscles of *he t'yebaii are to be soufjht in the most
liXpcriinentellc Stiulipii zur Kenntniss dor Iniiervatioti iter iiiiuri'i luul ilus-
scri'ii V'>Tii (\'i'.l(iiiuit(ii'iiis vt'rsoi'f^ti'ii Mtiskolii dcs Aiigcs. Arch. f. Opluh.,
Leip/. (1897). \V\. Ixiii. W. Ablli.. S. 4yi-.j'ir).
TIIK NKriJoNR AS TIIK rXIT,
|)i'(i.\iiii:il portions of the iiuclriis. .1. I'lrliiniicr is al prcsfiil cii-
<:;ii;('(l with iiir in tlic study of tiic spinal cords of animals
from whii'li pieces of ncrvi's supplyini;' nuisclcs, and in some ii,-
stanci's the muscles tlicnisclvcs, have hccn excised; tlieri'sults
of these invest illations will he published later. In Fiir. loHai'c
shown SOUK' cells from the nucleus nei'vi facialis lifteeii days
after section of the facial iiefve. 'I'he\ may lie com])ared with
i( of Fiji;. 14!t, which re])ivsents a nonnal motor ci'll.
As to the elTects U]io)i the cell hody induced hy injury to ;,
portion of tlu' teriuiiuiLs of the collaterals of a given axoiu", w.
have as vet lu) evidence.
n
a
Kk;. ir>l. N'l'iilnil lupi-ii cells ;' .111 tlic spinal curd ol' a cast' (if iiiiilliiilr iiruiitis.
I Alter I'.allil and Diilil.' nji. ((dls slaincd willi iiiddcanniii : <■. irll slaincti
with lin'nialux.vliii ; (/, ctdl slai'iid li.v Nissl's niclliod. 'I'lic alliialiuns in
tlic ( ludinalic .snlistanci' and llii' ilisldralimi id' llii' iiin Itiis arc wc II sli iwn.
Kx])erinu'nts such as the t'ore<>-()in,u' place certain diseases —
for example, tlu' so-called ])eripheral lU'uritis— beur :s in an
entii'ely lu'w lii,'ht, for it is obvious that even if the ; .d i)ro-
cess be conliiu'd at first exclusively to distal portions of the
axoncs (tiio lesion, when of the nature of a focal tu'crosis, is
\
238
THE NERVOUS SYSTEM.
usually dependent upon poisons circuliitin^ in tlie blood), it
does not remain localized in them, and, as we have seen, injury
to an axone leads t<t alterations in the whole of the neurone to
which it belongs. Ballet and Dutil * have already described
such changes in the cells of the ventral horns in cases of poly-
neuritis (Fig. 151 ). Many additional examples of the bearing
of these experiments upon pathology migiit be given. From
what has been said it is obvious that we must be very chary of
denying the existence of altera-
tions in the cell bodies of the
jieurones in n given disease, un-
less these have remained undis-
covered with the most delicate
methods now at our command.
There can be but little doubt
that in many cases in which the
nerve cells have been described
in the bibliography as being per-
fectly normal, very distinct path-
ological changes could have
been demonstrated in them had
Missl's nu'thod lieeii used for
their detection. On tlie other
hand, it must be borne in mind
that in the very delicacy of tiicse
methods there lies the great
danger that with them the in-
Fkj. i.v,>. Xtrve (ill iroin (•cniirMi experienced may easily be led to
cortex of (loK. It sliows iiltci'iilions , ., ii i • i n t
(liicily ill the (liiid rites tiinicd to- describe pathologiciil huduigs
Wiird a throiiihosed vessel. (AHer .^1, ,.,.,. j,, ••(.jilitv iioin' evi'^t I
Monti. Areh. ital.de l.iol.,t.x.\iv.) WIRIC, in 1 1 aillV , UOUC t MSt. 1
must confess tlitit I nm very
skejiticiil of accepting as fiicts the statements in any publica-
tion of work biised on XissFs niethods where I am not sure
thiit the results have been controlled by an investigtitor of
experience.
Unfortunately, tissues fixed for staining by .Xissl's method
ill alcohol or corrosive-subliniiite solutions tire not suitiible
for staining by the method of Weigert or by that of .Mtirchi.
* Riillet. (J., et A. Dill 11. Siir nil ens iW iMilyiieurKc iivcp lesions mediil-
lairt's. Hull, el inein. Sue. med. d. lioi.. de I'ar., ;{ s., t. xii (ll^i'-Tij, 1>I>. H1H-H2I.
THK NEURONE AS THE TNIT.
239
MariJiii * has tried to obviate tliis difficulty. His fixiuff rnix-
tuir (formol and chromic acid) permits of staining of the
tissues by the methods of
Weigert, Xissl, and Van
(iieson. The Xissl j)repara-
tions are not, liowever, so
beautiful as those prepared
in tlie orthodox way.
As regards the effects
on tiio whole neurone result-
ing from injury to its den-
drites we have much less
detlnite information. Leav-
ing out of consideration in-
juries to peripheral sensory
nerve fibres, which, as we
have seeTi, corres])ond in
tiieir end)ryol()gic.d origin
to dendrites, and which, as
1 shall point out a little Fm. l ■'):{. Larger pyramidal tflls fnnii ilic
, , ., , „ . . second laviT 1)1' tile fcn'l)ral cortex slmw-
later, thou-h conforming m in^ advance.! stages of d.Kciuration lul-
their phvsj. ..gical behavior, l"win^Micin ,M,isoMinK..ir.mrteen li.mrs'
1 - '^ ' duration. I lie < tils have lost tlic an;.'n-
iit least so far as the con- 'i'l'ty of tiuir <(>ntonrs. (After Jl. ,).
, . „ ... IJerklev. .lolins Hopkins llosp. Uep..
dnction of nerve impulses is vol. vi, I'l. .\ii.;
concerned, nither to what is
genenilly true of detidrites than of axones, are nevertheless his-
tologically indisputtibly tixones, we have as dtita in this connec-
tion only the observations of Monti f and Berkley.^ These ol)-
servers, employing the silver method of (Jolgi, the former in
cases of iiumitionand experimental cerebral embolism (Fig. l-Vi),
the latter in sevend varieties of intoxication (Fig. 1515) and in
*Miiriiia, A. Kino Fixiitioiisnietliodo. boi woIcIilt sowohl die Nisisrsche
Nervoiizelle als die Wci^jrcrl'schc .Marksclieiilefiirhuiifj geliiist. Neurolof;.
(Jcntraihl., lieipz.. Ikl. xvi (lISDT). S. HiG. ,
f All cpitoine of t lie work nf Italian iiivesti)j;ator.'i with (i()lj,'i's inetlKid
with rcf^afil to iiatli(il(>f,Mcal alterations in nerve cells is to ho found in tiie
eoinprelu'iisive review of ('. Saeerdotti. in Ijiibarsch-dstertajf's Mi'f^eliiiisse
der allgem. I'atholojjie ii. patii. Anat. des Mensciien ii. der Tiiiere. Zweiter
.lallrJ:an^^ IHjm. Wieshadeii (1H!»7). S. 7!t!»-800.
I IJerkley, II. .1. Studies on tlie licsions produced liy the Action of Cer-
tain Poisons on the Cortical Nerve Cell. Johns Hopkins IIosp, Uep.. I5alt.,
vol. vi (1M!(T). fasc. i. pp. 1-88.
f
*
: m II
It
i
-ri
W\ /i
('
, I'
I
'J4()
TlIK NKHVOUS SYSTEM.
tcniiiiuil (Iciiiciitiii (Fiir. 1'">1^), liiivc found tluit uiidor oortniii cir-
cuiii.sliiiici's till' (.'arlic'sl k'sions which ijppcuri'd were those ull'cct-
injjf thi' dendrites. Those showcil varicosities ;iiid distortion
pheiiomenii willi loss of tiie ii'cinniidcs and Unci' side hriUKdu's;
^^^^^^^^^Er^^^^HH
•
ffl
■
M-
I^H
»
•
■ ^ »
^^1
' W. '
■
>.
^^1
■■*
I
-• .
•
H
,%'
■
.J *
H
*^H <^^^I^^^^^H
^ -' ^L
^^^^^H
''^^^^■^^^H
^H
-• ' • ^ « '•
^^^H
^^^^1
'■ '*•.
^H^^H
' M
^^H^^l
i , . ••.^:
■
* 1 *
HH
f ..i
I
*',-.;i ,-
^1
' » .
PI
I^^Pr
^^1
^^H
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i
H
r
^■^
^^1
-'S ^ '
^^^1
^^^^■r y^
^^^H
A
1
wty^
■
U
1
(t. h.
Flii. lot. St roiii; apical (Iciidiitcs nf ipyiMiiiidiil (ills rnuii the luiiiiaii (■criliral
ciirlcx. ((, iiipiiumI clciidritc ; A. (Iciidiitc rniiii a iiyraiiiidal <ill in a case .pf
tiTiiiiiial ilciiK'iitia ; llic ki'IiiiiiiiIcs have disa)i|K'ai'<'d and the iirc^iular
lalilprc is well shown. i.M'tri' II. ,1. Iicikity. i
only subsequently did the oell l)ody and axone slio^v alterations.
An effort has been made to attribute tlie ehaiifijes in sueli cases
in the axone and cell body to the disturbiinces in nietabolisni
resulting from the loss of the dendrites. It would seem to me
possible that the alterations in external form in a cell I)o(ly and
axone discovered l\y tlie method of (Jolgi may be due to the
same causes as the ])rece(ling changes in the form of the den-
drites and not sim[)ly be their m"tabolic setpiel.
The researches of Warrington i^vidn iiift'(i) and others have
shown
dendri:
neuron
if the
ulterati
tlian til
the con
collator
another
ogist.
comniui
them, tl
culating
That
tion of
the nuci
intimate
matter (1
Hesidi
the rest t
has long
inevitable
connects
be recalh
ligature
the point
results a ]
extremitid
necrosis o
cord. Th
Miinzer ai
complete
the necrot
degenerati
% the ni(
(either thi
ablation) i
axone, and
*Sliiniaiii
3cliciikelf,'eger
lM^^z. (1894),
r
THE XKrUONK AS THK r\TT,
241
sliown tliat if the impulses cotnin'f to a oell hy way of the
dendrites and cell body he i-ut off, clianjfes in the whole
neurone result. It would not he ditticult to l)elieve then that
if the dendrites midergo serious injury of any sort marked
alterations of the neurone must result, if for no other reason
than the cutting off of centripetal impulses. Ileld's studies of
the concrescence-relations between the termiiuils of axones and
collaterals of one neurone and the dendrites and cell bodies of
another are, it seems to me, v*-ell worthy of note by the pathol-
ogist. When one remembers that these delicate interneuronal
communications are directly exposed to the lymph which bathes
them, the possil)le deleterious effects of soluble poisonings cir-
culating in the blood and lymph are not diffit-ult to imagine.
That the cell body is of very great importance in the nutri-
tion of the neurone is evidenced by (1) the existence in it of
the nucleus with its surrounding endoplasm, and {'2) its very
intimate relations to the caj)illary plexuses within the gray
matter (Kig. 155).*
liesides, the effect of severe injury to the ganglion cell upoti
the rest of the neurone is now very generally appreciated. It
has long been known that destnu'tion of a ganglion <'ell leads
inevitably to the decay and disappearance of the nerve libre
connected with it. A few interesting experiments may perhaps
be recalled. Ehrlich and Hrieger showed in 1884 that if a
ligature be applied for thirty minutes or an hour close beneath
the point of origin of the renal arteries of the rabbit, there
results a })ernuinent sensory and motor paralysis of the posterior
extremities and of the bladder and rectum, owing to acute
necrosis of the cells of the gray matter of the lumbar spinal
cord. These experiments, repeated later by Ilerter, Spronck,
Miinzer and Wiener, and others, are invariably followed by
complete degeneration of the whole of the neurones of which
the necrotic; cell bodies form a part, and the course of the
degenerating fibres can after a few days be profitably studied
by the method of Marchi. The removal of th'- nerve cell
(either through chemi<'al injury, cutting off of nutrition, or
ablation) is, for the part remaining, ecjuivalent to severing the
axone, and the tyi)ical secondary degeneration always occurs.
♦Shiinainura, S. Ueber die lUiitversorgung «lcr Pons- luid Iliri-
.schenkelgegend, insbcsoiulore des Oculoinotoriuskerns. Neurol. Centrall 1.,
fioipz. (1894), Hd. xiii, S. 08"); 769.
17
m
-51
i
; •■{
1
1 .
I
1 .
/I
I "1
m-'
[ I
I : ■!
L>42
TIIH NHKVors SYSTEM.
Tliis l)ri)i^'s us to the iitilizjitioii of cxpcriiiiciitiiUy pfodiicod
sc'coiidiiry (loj^t'iicnitioiis, hy inciiiis of wliicli iiiiportaiit coiiti'i-
hutioiis liavi' Ix'cii iind iirc Ix'iuif iiuidc to tlic iinatoniy of the
central nervous system. No matter \\ liat nerve cell or ^'roup of
nerve (!ells is destroyed, wlietlier in the s|)inal cord, in the
medulla, in the thalamus, or in the cerebral cortex, whether
belonging to the projection systems or to the association sys-
a.
A.
&
C
e
•■'■■S^'^':/'"jik.X'-' '^^
*-
V'- ' *>■». '-■-.■ .'•*--■
•:/
I ' ,--1
?«i*
^
I'ki. I.').'). KrriiiiMl section tlirip|i;,'li ll'c incsciiccjilialuii sliiiwiii^ vascular supply.
Al'tcrS. Sliiiiiaiiiiira. Neurol. ( Viitrallil. I,ci|(/., I!cl. xiii * isitl , S. 77.'), I'"ii;.4.i
ti. miclciis cipipinis (|iia<lrali ; /(, I'cjjio nuclei nervi ((culonnpliuii ; c. fas<'icu-
lus liiiifiitudinalis niedialis: </, leiuuiscus; /', sulistaulia iiijira ; ;/. l)Msis pe-
(luuculi ; /(. iiipieiluclus cet'eliri ; /', vess<'l luuniu^' aUmt; iiciir I'aplii' : ./', lateral
l)lo(i(l-vcssels : /.-. hidod-vessel runiiinji aluufi the liasis peiltiiieuli. The rich
capillary supply to the ji'nups nf nerve cells is parlii iilarly well slmwu.
I
•'
I
ti'ins, the corresponding axone or tixones, with their enveloping
myelin shetiths, degenertite completely to their terminiils. The
method of Marchi permits us to nuike out the clumges long be-
fore they assume the degree neeesstiry for their recognition by
Weigi'rt's method. Indeed, nowadtiys jiriieticidly every neuro-
logical investigator employs this })roci'dure, so valu;il)le is the
information afforded by it.
This njethod, when employed in (•(♦nnectioii with thtil of
Xissl, is of extreme viiliu', not only for antitomy, but iilso for
ptithology, for it must now be evident tluit oni-e we have
domonstriited degeneration in a given set of nerve fibres we can
pntphesy tilmost with certainty the existence of lesions of some
Till-; NKL'UONK AS TIIK I' NIT.
24:5
sort ill tlit'ir cells ol' origin — U'sions whicii, however, iimy
()l)viously, IVoni wliat has been said above, be, in a ijfiren ease,
either [)riinary or secondary. 'IMie statement of this fact would
seem to 1)0 all the more important in that it has been su<,fgested
!)y some iuve^itifjators that apparently trivial injuries to
neurones, so sli<fht in the cell body as to exclude detection l)y
all the cruder methods, imiy lu'vertheless in all probal)ility
sutlice to jfive rise to easily (lemoiistral)le degenerative lesions
in other parts of the neurones. I'erhaps the most significant
instaiute which can be eited is that met with in some forms of
lateral sclerosis in human beings in which the pyramidal motor
cells of the cortex show no marked lesions, though the most dis-
tal portions of the lu'rve tibres arising from them have gradually
degenerated. While it is jiot impossible that here, as seems
probaI)le in some forms of disease of the perii)heral nerves
(alcoholic neuritis, lead-poisoning, etc.), the degeiu'ration of the
distal portion of the axones may be due to the direct action
upon them of some toxine, the view is gradually gaining
ground that in these cases we. have to deal with sonu' deleteri-
ous intlueiu'c acting upon the cell body, or perhaps upon the
whole neuroiu', which expri'sses itself in a inaniu'r accessil)le to
recognition !»y our methods first in those i)ortions of the neu-
rones in which the nutritive infiuences are leust active, jtre-
sumably those most distal from the cell Ijody and nucleus
(Stn'impell). Wollenberg's idea regarding the primary seat of
the disease of the sensory neuroiu's in tabes would involve a
similar exjdanation, but many have objected to the assumption
that in this disease the primary lesion is in tlie cell Ixxlies of
the spimd ganglia.
ij ,,.
Inasjiiueh as in fal)es we iiave not, as after section of a dorsal
nerve root, a complete degeneration following tlie continuation of
file lil»res within the s])iiuil cord, but rathei- an elective degenera-
tion of (lie dorsal funiculi, certain only of the intramedullary con-
tinuations of the dorsal roots being involved in the disease process,
at least in the early stages, it seems to nie that one of two views has
to be accepted for the explanation of its origin. Either this is to 1)h
sought in a slow intoxication of tlx- cord, the toxine beinii- one tiiat
inllnences deleteriously the sensory rejrions of the cord and by pref-
erence only certain parts of these, the individual bundles winch
succund) varying to a certain extent indifferent cases of the <Iisease,
or the toxic pnicess is exerted in an elective way in (he sjjinal gan-
LTm
(
i
■Ij;
24+
TIIH NERVors SYSTEM.
^lia, or pussihly on the wliolc of the pcriplicriil scnsoi-y iicuroiic,
(•(•I'tain only of llit' |K'rii)lit'i'al sensory ncui'oncs bcinjr atlVctcd, at
least at lirst, and accoi-dinyly certain only of the tibres of tlie dorsal
funiculi inside tiie <'ord. Tlie former view lias been supported hy
Erb. Striiinpell, Milbiiis and otiiers. A result of poisoniny some-
what similar to that assumed in this doctrine of the oriffin of tabes
has l)een observed in ceilaiii other intoxications. Further, notliinj^
can be more ol>vious than that t-ertaiu ;^rouj)s of neurones in a
{fiven individual are more susceptil)le than others to a j,nven toxic
a'fent ; more than this, the same <,''roup of nerve cells in two indi-
viduals may react very ditl'oiH'utly to similar doses of the same
poison. Our daily experience with the etl'ects of alcohol, cottee, tea,
and certain ana'sthetics upon ditl'erent individuals and upon our-
selves under dillei-ent circumstances are of interest in this connec-
tion. The toxiaes of .syphili.s, although we are entirely ignorant as
to iiieir nature, show a decided ])reference for certain parts of the
cerebral cortex, other areas beiny less often att'ected. llampe's ob-
servations conceiMiinj,'- the diU'erences in the psychi<' distur]»ances
followinf,'' carbon-l)isulphide i)oisoninK' in ditl'erent individuals are
very convincing' in this re{»'ard, as are also the careful psycho-jjliar-
macoloofical investigations of Hoch and KraejM'lin * concerninj,'' the
catleine and ethereal oils in samples of tea. It is Flechsig's idea
that these variations in vulnerability of diti'erent g^roups of neu-
rones, and of the ditl'erent jjortions of the individual neurones, an^
to be traced back in larye part to develoi)mental conditions, a suf,''-
gestion which is highly i)Iausible in view of the evidence that can
be brought forward in its favor.
The answers to the questions which we have fornmlated
concerning the events occurring;; in the various component j)arts
wlien cut off from the main body of the neurone, and tlie effects
of lesions of individual portions of the neurone upon tlie neu-
rone as a whole, are, of ne<.'essity, as yet very incomjilete. Suf-
ficient evidence, however, is at hand to render clear the fact
that the neurone as a icltoh' is a trophic unit, and that any
attempt to locate the trophic function exclusively in any one
portion of it must assuredly fail. We have seen that we possess
reliable observations which all favor the view that injury to any
part of it also affects to a greater or less extent the remainder
of the neurone, and that no portion of a neurone is capable of
existence for any great length of time after the severance of its
♦ Tloch, A., u. E. Kraojii'liu. I'obcr die Wirkuiis dcr Tlu'obi'stjuKltlicile
aiif k()rpi'rli('lii' uud gcistige Arbeit. Kraepelin's Psyciiolog. Artuiiteii, Bd. i
(1H!)5), H. 2-3, S. ;57H-4H8.
THK XKURONH AS TIIH TNIT.
2io
coiiiu'c^tiou witl) the rest of tlic nerve unit. And after all, when
one thinks of it, tliis is not so very astonishinj^ ; indeed, it is
rather a matter of surprise that the fact should have been ques-
tioned, after the knowledge had onee been gained that a neu-
rone as a whole represeiitsa single cell, for we have long known
that even in such i)resuniably little differentiated protoplasm as
that jiossessed i)y an anueba, an injury (for exam])le, with silver
nitrate) to one portion of the cell body is speedily answered by
phenomena which concern the whole of the unicellular organism.
How little likely that a nerve cell, the protoplasm of which
n'presents the highest example of differentiation along the
liiu's of irritability with which we are acfjuainted, should
i'emain uninHuenced by irritation or destruction of one of its
integral jiarts !
.Many facts juight be added in connection with regeneration
(if nerve fibres and nerve cells which have more or less bearing
upon the trophic functions of the neurones. On the regenera-
tion of lU'rve fibres an immense amount of work has been done,*
some very im])ortant contributions having l)een made by inves-
tigators in this country, especially by Howell and Huber.t It
has long l)een known that on suitable apposition of the ends of
a divided motor or sensory nerve, the axones of a central stump
may grow out again to the periphery iind function nuiy again
return. In the event of the rc-establislunent of coniu'ction and
function, the regressive alterations which begin to apjjcar in
the central portions of the neurone almost immediately after
section (Nissl) gradually give place again to the uornud ap-
pcaraiu'cs. The investigations of I'acr, Dawson, and Marshall,
carried on under the direction of \V. H. Howell ( !S!lT), speak
in favor of the regeneration of the central axones of peripheral
sensory neurontss in the dorsal funiculi of the cord after experi-
* ("oiiiptu'e the excellent review and i-rituiue of the bil)liogniphy up to 1895
liy II. Stroi'lie. Die ali^jeiiieiiie lIisloloj,'ie der degeiierativen uiid regeiieni-
I ivcn Proecsse iin ceiitralep. mid jicripliorcn Nerveiisystciii nadi deu nciiotcn
Forsehmigen. Zusaniiiieiit'nssendes licfenit. Cciitrallil. !'. allg. Path. ii.
liatli. Anat.. .Fena. Hd. vi (IHir)). S. H4!MK)0.
+ lloweli. W. II.. and Iliilier, G. ('. A Pliysiohtgk'al, Histological, and
Clinical Study of the Degeneration and Kcgeneration in Peripheral Xcrve
Filiresafter Severanee of tlieirConnections witii the Xerve Centres. .T. Pliys-
ioi.. Candiridge. vol. xiii (ISiri), pp. ;i:).")-4(H!, and vol. xiv (180:!), p. 1 ; also
lliiber, (i. C. A Study of the Operative Treatment for Loss of Xerve Sub-
stiinee in Periiilieral Xerves. J. Mor|)Iiol.. Most., vol. xi (IHito), pp. 6'29--740,
'•U * /i
I
: i'
i>4»;
TIIK XKKVors SVSTKM.
i
iiii'iitiil lesion of ii (lorsiil root Ijutwui'ii I lie <;iiii^lioii spiiiiilc and
the spinal cord.*
Kcf^ononitioii of severed nerve lilircK within the spinal cord
and I)rain is, nnfortnn;itely, very ninch less cnniplete than in pe-
ripheral re;;ions. Whether a nerve cell once entirely destroyed
can have its place ade(|nately (llled hy one formed hy division
from another nerve cell is a (|Uestion of vital interest. Tiio
reseurches of Tiji^^es, .Mondino, Coi-n, Cattani, and I'opolf are of
importan''e in this connection. 'IMie newspapers have recently
contained the most e.\a<,'<i;erated and hidicroius acccnints of the
si<jnilicanee of the experiments (jf N'itzon.f Accord injj to his
researches, there may be an actual new formation of nerve cells
in the 1)rain, and it is his opinion that the restitution of func-
tion after ahlation experiments is to he attributed, not, as
Luciuni ami 'rami)urini think, to the existence of secondary
centres which take on the function vicariously, but directly to
the lu'wly formed nerve tissue. This view is not shared l)y 'i'e-
deschi,! ">f I'isa, althon<;h this investij^ator also asserts that he
has (lenionstratc(l the possibility of a re<i[eiU'ration of the nerve
cells (Kij,'. !")()). It is hijfhly desirable that these studies be
repeated and extended, especially as the recent researches of
'Pirelli * on the s])inal f,'an<flia, and of Monti and Fieschi || on the
sympathetic iTiinirlia, <,'<) to su]>port the prevalent view that in
adult animals ,iLtanj,di()n cells once di'stroyed arc not re<ieiu'rated.
That there can be remarkable regeneration in end)ryonic stages,
* IJiicr. W. S.. Dawson, P. M., iiiul II. T. ^hirshalj. IJcjijciicnilioii of tlic
Dorsal liool l''il)n's of tlic Si-ooiid CiTvieul Nitvc wiliiin tlic Spinal Coi'il.
.1. Kxpcr. MiMJ.. iJall., vol. iii (1899), Xo. 1.
t Vil/on. A. N. La nooforination ties ('(^llulos ncrvonsos dans le corveaii
ilii sin;^e fons(''(;iitivi> a I'aljlation coniph'ti' dcs lolics occipitaiix. Coinpt.
ivnd. Sou. l)iol,. Scptcnibcr 1(>, 189.') ; also in Coinpt. rend. Acad. d. sci.. I'ar.
(1895), cxxi. 44.'"»-44T; and in Arcii dc piiysidj. norm, ct patli., I'ar. (1897), T)
s., t. ix, pp. '29-4;{, 1 |)1.
I Tcdcsclii, A. Anatomiscii-patiiolofrisclio und experinipntclle I'nti-i-
snchnngcn ilhcr dii- {{cj^MMieralion dos N'crvcn;,M'woh('s. Vorl. ]\!iltli. Ccn-
trallil. r.ally:. I'atli. u. i)atli. .\nal...Icinv. lid. vii (lS9(')).S.449-4r)l ; also Anato-
iniscli-oxpeWnicntoller Boilray zuni Stndicn dor Rogonoralion dps (U'wobf
di's (VntralniM'vonsystcms. Moitr. z. palli. .Anat.u. z. allj;. I'alli., Jena, 189T,
xxi, 4;{-Tv>. ;i |ii.
* Tirclli. V. Dei propo.ssi ripiirativi nel ganifiio intervcrtpbrak'. .Ann.di
frcniatr. <■ sc. aflini, Torino, vol. v (189')). pp. 9-'2(l ; also Transl. in Arcli. it.il.
dc liiol., Turin, t. xxiii (189r)-'96). pf). :!01-:!l(i.
I ^foiiti, A., ct Fie.schi, D. Snr la guprison iIps blossures des ganglions
sytTipatliicpip. Arch. ilal. dp Kiol., Turin, t. xxiv (189r)-'9C), pp. 4()l-4i:{.
Iioweve
Loci), ii
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* Flexn.T
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'Morpliol.. I!,,
TIIK NKrUOXK AS TIIK I'NIT.
'2Vi
however, is I'lilly estiildislied ; witness the experiiiieiits of Hoiix,
Loel), iiiul otliers. Klexiier hiis recently stndieil witli eare thu
V "*
Q^^••^'v'^
•r t^
V- ©
h'l(.. l.")((. -( iiryiicinilic tiymcs in nerve ci'lls in ln'iiin nf iId^ llinc <1m.vs iiflcr
inlrciilni'lion ul' I'mriKn licidy. ( Alter Tt'dcsclii. > l''i\uti<in in I'MeuniiinK's
niixinie, sill'ninin stiiininK.
process of regencrution in phmarians with especial reference to
the liistolo<jical sitlo.*
Of these phenomena of reireneration it may he said hrielly
that they emj)liasize most sti-ikin^iy the cellnlar nature of tlu*
neurones, and accord in nearly every particular with what (t
prlnri miilht have l)eeii expected.
I have purposely laid particular stress upon the unity which
(diaracterizes the trophic functions of the lu'uroiu', hecause the
Wallcrian doctrine of tro[)liic centres has been so ingrained in
our minds that it is ditlicult to disabuse them of the erroneous
])ortions of it. In making this point, however, then' has been
no intention of giving the impri'ssion that all portions of the
neurone are of e(|Ual value from the standpoint of nutrition.
Siudi an idea would jirohably involve a fallacy even greater than
the one from which we arc being emancipated. Kxactly the
part played by the dendrites, l)y the cell liody, and by the axone
in the nutritive ])rocesses it is as yet impossible to say; but that
each has an imjiortant function is certain, and tiiat the role of
the non-mednllated portions of the neurone is somewhat ditl'er-
cnt from that of the medullated seems very likely.
We have now to turn our attention for a sliort wliile to the
phem)mena of irritability as manifested by the neurones, and
shall return later to consider the relations of the trophic func-
tions to the nervous functions })ro])er.
* Flexnor. S. Tlic Uefjciicriition of llio Xcrvons System of Plaimria
torvii iiiiil tlic Aiiatiiniy of the Nervous Systeni nf I)()ul)le-lli'a(li'(l l''ornis. ,1.
:\Iiir|iliol., liost., vol. xiv (18!>T-'i)8). pp. :{:!:-:{4(;.
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CHAPTER XXI.
TIIK IKKirAIULlTY OF THE XErUOXEP.
The jihononiona of irritaliility of the iiciinnu's — Applicahilify of the law of
the conservation of einTgy in the domain of animal life — 'J'ho problems;
to be solved — I'nremittiny character of the activity of the neurones —
The majoritv of the nervous processes unconscious — SiiiiiifU-ance of the
so-called "subconscious" and "infraconscious"' centripetal and cen-
trifugal impulses — Question of spontaneity of neurone activity — On the
transf<>reni-e of an excitation from one neurone to another — The " neu-
rone-threshold " — Importance of proper a<ijustment of stimuli — Ed-
inger's theory of tabes — The specific energies of nerves.
The physiologist of the present day see.« in the ftmctions of
tlu' nervous system, even in those wliidi are most complicated,
only certiiin manifestations of energy. Moreover, he helieves
that in neurones, its in till other cells of the body, and as in the
world generiilly, the law of the conservation of energy during
transformation holds, and consequently regards the phenomena
of irritability, as exhibited l)y a lu'uronc or l)y groups of neu-
rones, as the kinetic re])resentative of the potential forces of the
cells and their food stuiTs. The mettiliolic activities and the vital
manifestations of the cell are concomitant i)rocesses — iinother
example of the inseparable connection which exists between
what we term matter tind energy. There has been in many
quarters a certiiin iimount of hesitancy in accepting the view
that the capacities of the nervous system, particularly those of
the l)rain, tire dependent directly upon the chemical and phys-
ical alteraticms which arc continuiilly going on within its con-
stituents — a hesitancy which, though it has in the ptist proved
a si'rious ol)sta('le to progress, is hii])])ily now fast disappearing.
F'or the plant, all tlu- evidence goes to i)rove that under the in-
fluence of suidight and iu'at nnirked chemical and physical
changes take place within it which we recognize in its vital
l)rocesses. In the animid, be it granivorous, carnivorous, or,
like num, omnivorous, it is the chemical energy introduced as
:24S
THE NEUIION'E AS THE UNIT.
249
food which represents in the main the source of the energy of
the organism. The recent accurate calorinietric studies of
Rubner * are of much interest in this connection, and demon-
strate in a most convincing way the applicability of tlie law of
the conservation of energy in the domain of animal life. While,
however, our present knowledge suffices to permit the recogni-
tion in groups of living cells of these broad general laws, which
were formerly thought by many to be applicable only to inani-
mate nature, it must be admitted that in no single instance are
the details of the transformations of energy known to us in any
legree of completeness. We have not as yet discovered very
much that is definite concerning the storing up of energy in-
side the individual neurones, and our information relating
to the discharges of energy in these structures is even more
scanty.
The physiologists have been struggling for fifty years or
more to gain an insight into the nature of what they call nerve
impulses, by which is to be understood the occurrences inside
axones — for example, at the time when we have good reason to
l)clievc that they are functionally extraordinarily active. Their
efforts have supi)Iied us with a multitude of data, physical and
chemical, interesting enough, no doubt, but which can serve as
only the barest prolegomena to an explanation of the esseiice
of the occurrences. If we are so badly infornu'd concerning
these elementary and fundamental phenomena we may very
\\'A\ be content to be modest for some time to come in our
claims as regards a jdiysiological ijsychology. It is by no means
impossible that in the nervous system forms of energy are con-
cerned which do not exist outside the aninuil body and which
yet remain to be recognized and studied.
It would be easy enough to outline rapidly the most salient
points with which we need to l)e better ac(|iiainte(l. The dif-
ferences in neurones in different species of animals, the influ-
ence of heredity upon the structure of the neurones, the auto-
matic activities in these cells, if indeed they have any which
an absolutely automatic, the changes in neurones resulting
from cheuiical and physical alterations in their environment,
tlieir powers of ailaptation, and many other ({uestions present
* Kubiier. M. Diet^iU'lkMlfrtliieriscIiLMi Wiirine. Ztsclir. f. Mini., .Miiiirli.
u. lA'\]y/... liil. XXX (lHi)4), S. 73-142.
A
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I
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TIIK NKKVors SYSTKM.
thfiiisi'lves, the solution of any one ol" wliich would l)iMn<i about
a <rrt'at advance in our knowli'djfc. Truly, to find out tlio
|)i'()])('rtics of a sinji;k' ncuroni' would be a task appatlini;
i'nou<rh, but wlu'u we renu'inber that of the niillioiis of iicunini's
ill one individual ])erlia2is no two are just alike, the ([uest
would seem hopeless. Hut instead of burying ourselves in
pessimistic reflections, or being discouraged by what is at pres-
ent unattainable, by what may perhaps forever remain to us
unknowable, we may profitably turn to the consideration of
some of the points which lie more within our ken.
One ])oint, self-evident enough when one's attention is
directed t<» it, but which often appears to have been overlooked
in connection with the neurones, is the unremitting character
of their activity. A\ itii a metabolism so complicated as that
occurring within the nerve units it is inconceivable that there
can be any jteriod in which alterations in chemical structure,
and conse(pieut!y energy transformation, are not going on.
From moment to nioment, throughout all the hours of the day
and night, analytic aiul synthetic processes are taking place,
associated with the alterations in physical forces which neces-
sarily accompany tbese changes. In common witb everything
that lives, the neurones know no absolute repose. As I have
said, in speaking of their metabolism, periods of extravagant
activity may alternate with periods of more economic change,
but total rest is inconsonant with coJitinuance of existence.
We are forced to believe that what we ordinarily speak of as
the passage of a nerve '.mpulse represents, as it were, a stormy
process in the nerve fibre, and that just as absence of a storm
does not nu^an absence of weather, there are in all ])robability
minor alterations, currents if you will, ])assing to or fro or to
and fro in a given nerve fibre in the intervals between the
more violent excitations. With increasing knowledge the im-
portance of centripetal impulses which fall below the thresh-
old of consciousness and of centrifugal impulses insutlicient to
call forth visilde muscular contractions is becoming more and
more evident. In a healthy individual ])erhaps the majority of
the impulses passing from the periphery info the lU'rve centres
have no share in the composition of the mental pictures, but
these subconscious stimulations are doubtless of decisive signifi-
cance for flic nufrifion of the elements concerned and for the
processes of subconscious co-ordination. [Similarly, tlie myriads
n
THE NIirilOXK AS TIIK UNIT.
251
ot' ijiipiilsos pussin-r to tlic imisclt's without prodiu-iuju^ marked
coiitnictioiis ill tiu'iii must of necessity have to do not only
with the })r()p('r nu'tiil)olism of the motor neurones, hut also
witli the nutritive processes in the muscles themselves. In-
deed, there is much evidence to show that the nutrition of the
muscles can he kept up very well in the ahsence of active uius-
cuhir contractions so long us these less violent iuipulses pass
regularly to them, but as soon as the latter are cut off the
uiuscU's speedily undergo atrophy. Tliis fact is often extremely
well illustrated in cases of hys'.erieal patients, where, as is well
known, there may be inactivity of certain muscles for very long
periods without any very marked atrojihy. Hy means of very
delicate graphic nu'thods it can be shown that the mnscles in
such ](atie]its are innervated when corresjionding movements
are thought of, just as in a healthy individual the hearing of
the word "tower" is often associated with nerve impulses to
the eye muscles, which tend to make the individual look up.
The different tracings yiidded l)y the automatogra])h during
various psychic processes may be mentioned as interesting in
this connection. The iinportance of the continuous passage of
iin])nlscs along the sensory nerves for the carrying out of all
complicated movements of the muscles, long em})hasized by
the obsi'rvations upon tabes and also upon cases in which there
have been lesions of the trigeminus, has been made even more
strikingly evident by Mott, Sherrington, and others who ex-
perimented upon monkeys in whom the dorsal roots of certain
of the spinal nerves had been cut. In such animals, although
])ra('tically all the motor neurones (except the few ]>ossible
motor axones of the dorsal roots) are intact, and the memory
traces of previous movements must be believed to still exist,
movements of the liml)s innervated by the corresponding seg-
ments of the spinal cord, those , hich are com])licate(l as well
as many which are (piite simple, are only very inaccurately
carrit'd out. The continuity of the nerve excitations can
therefore scarcely he insisted upon too forcibly, and I am in-
clined to agree fully with (jioldscdieider when he says, '• Ks
herrscht eine zeitliche ("ontinuitiit von Krregungen in alien
Bahnen des Xervensystems.'''' As Donaldson.* writing in this
connection, beautifidly puts it: " In this picturing the entire
■! ; "'
i:
M
/i
nm.-
* Op. n't., p. '284.
9
fill
I
I'::il
ih
'.
252
TIIK NERVOUS SYSTEM.
nervous system us a sensitive nicchanisni, it is evident that it
must resi)ontl to tlie surrounding stimuli as does the water of
a hike to the hreeze ; and such is the rehition between the
central system and its environment that the breeze is always
blowing and the waves of change always chasing one another
amodg the responsive elements. If t''ere are no waves, then
the cells are dead. The breeze still blows, but it falls on a
frozen surface, on cells chilled and rigid beyond the power of
response."
The influence of the arrival or non-arrival of external stimuli
to the ni'urones upon their trophic and nervous functions will
be referred to a little later. If among external stimuli we
class not simply those outside the body, in which event a very
minute fraction of the whole number of neurones would be
directly accessible to external stimuli, but all those external to
a given neurone, including those arriving through the lymph
which bathes it, or l)y means of the ])rocesses of other neurones
which enter into relations of conduction with it, wc shall come
to the conclusion that the limits of genuine spontaneity of
action on the part of neurones are very narrow ; indeed, sonu^
authors would deny its existence altogether. Von Lenhossi'k,
for example, says: "Man darf den Satz wolil als gesichert
betraclitcn, dass es keine Ncrvenzcllc giel)t, die ihre Merven-
wirkungen aus s' ii selbst heraus, ohne aeussere Impulse, spoji-
tun cntfalten konnte." The reflex actiinis are very obviously
dependent upon external influences, as are also the instiju-tive
reactions, and what we call volitional movements are, when
analyzed, apparently only reactions to eAternal influences modi-
fied by memories. We must not lose sight of the fact, how-
ever, that there may be periods of considerable length inter-
vening between the arrival of the external influence and the
discharge of energy whicli it determines or lielps to determine,
just as we know that the springs of conduct often lie far re-
moved from immediate acts. And it is just here that the laws
bearing upon the summation of stimuli * assume an csiiecial
interest, although they must be passed by now without dis-
cussion.
* Cf. Du Rois-Iieytnond. Uobor die Ansl<")sunji von Rofloxbcwcgungen
(hirch pine Stinunc scliwaclu'r Koi/o, 18H0; also tlie review of tliis subject by
S. Exiier. I'^ntwurf zu einor physiologischen isriiliining der psychisehen
T'^rselicinungen 1 Tiieil, I.ei|iz. u. Wicn. Svo (1S94), Cap. ii, S. 49.
THE neuronf: as thk rxiT.
253
Of the pliysiology of tlic transference of an excitation from
one neurone to another, a word may be in phiee. All our
knowledge of sensation goes to indicate that a certain minimal
amount of stimulation is necessary to call forth a reaction ; for
exam])le, to stimulate a pressure point in the skin u certain
amount of pressure, say from a hair, is required to elicit the
sensation of touch. Any pressure less in amount will not suf-
fice. That is to say, the touch point has a "threshold value."*
In the same way there are threshold values for the various cold
points,! warm p.)ints, and pain points, and in connection with
the special sense organs much work has been done upon the spe-
cial threshold stimuli which will call forth sensations of light,
smell, sound, and taste. It is obvious, if t)ie neurone doctrine
be true, that for the spreading of an impulse or excitation
tlirough the nervous system one neurone must act as the exci-
tant upon the neurone or neurones beyond it whi(!h stand in
conduction relation with it. It seems highly probable, there-
fore, that each neurone has a special threshold value, (iold-
scheider,! in a brilliant essay recently published, has defined the
"neurone threshold" {Xeuronxrhivi'lle) to be the degi-ee of ex-
citation of a neurone which just suffices to call forth a fruitful
excitation in a neurone with which it is in contact ; that is, that
sutticient to call forth a sensation, a movement, etc. If this
view be correct, the resistance in the passage of the excitation
from neurone to neurone would, (ioldscheider believes, lie at
the point of contact or of concrescence of the neurones. A
series of new problems are opened nj) by this suggestion, not
only with regard to the easier propagation of impulses in habit-
ual nerve processes {Balututui) and with regard to the phe-
nomena of inhi])ition {Ifcnumaiff), but also with regard to the
therapy of nervous diseases, especially the explanation of phys-
ti'ia
t..
:-l|
/I
■ > ■ ^
n
* Cf. V. Frey, M. I'ntersueluingen iil)L-.- die Siiiiiesfunctionen dtT
inenschlichen Ilaut. Erste Abhandlung : Druckcinpfindiing und Schinerz.
Abhaudl. d. niath.-pliys. CI. d. K. Siichs. Gesellsch. d. Wissensch., Bd. xxiii
(1896), No. 3, S. 168-260.
t Harker, L. F. Ueher eiiien Fall von einseitiger, umschrieberier und
clcktivor sensibler liiihinung. Deutsche Ztsehr. f. Nervenh., Leipz., Bd.
viii (lH0r)-'96). S. 848-^58. Also Traiisl. in J. Expor. 31., Bait., vol. i (1896),
pp. ;J48-860.
X Goldsehoidpr. A. Die Bedeutung der Reize fiir Pathologic und The-
rapie ini Liehte der Neuronlehre. Leipz. (1898), Svo, S. 1-88.
I
254
TllK NEIiVOUS SVSTK.M.
ical tlicrapcutic inctlKMls like iiiiissa<jt' iind liydrotlicrapy. Tlic
luoiiograpli coiiit's to liaiul too late to he reviewed here in (h'tail,
but every iRUiroh)};ist will be repaid I)y a careful pt'rusal of it.
The iniportaiR'o of jiornial ade(|iiate stimuli fur the welfare
of the lu'uroiu's in health can no loiif^er l)e fpiestioiied. As van
(ieluiehteii has emphasized, without stiimili there can l)e no life.
For the maintenance of absolutely perfect function the relation
of stimuli to the re])arative nutritive power of tiie cell must he
absolutely and perfectly adjusted. .Just here the Krsatz-Theorie
of tabes elaborate<l Ity Kdin<fer can l)e easily understood. Kdin-
ger, under the intluence of Wei<fert, assumes that, if stimuli be
received in excess, a nerve cell is no loui'er able in the intervals
of active fuiuition to repair the loss sustained by the functional
activity. As a result, progressive degeiu'ration ensues. In cer-
tain diseases like tabes there is, in his ()])inion, an abnormal
impairment of the [)ower of restitution on the part of the nerve
cell, so that a given neurone i;i no longer able to keep up its nu-
trition even when the stimuli reaching it are not in excess of
what would be normal in a healthy body. As a therapeutic
nu'asure in tabes, therefore, he urges the importance of giving
more than usual rest to the neurones which are degenerating.
Thus, a man wlio has been com])elled to be much upon his feet,
and who suil'ers, say, from lumbar tabes, would be ordered rest
in bed. In cases of brachial tabes, exercise of the arms would
be interdicted. \\'ith beginning degi'iu'ration of the optic paths
reading and all unnecessary use of the eyes would be proscribed.
Kdinger asserts that he has, in nnmy instances, not oidy been
able to arrest the progress of the disease in this way, but to
markedly ameliorate symptoms already present.
In many cases of lu'urasthenia associated with pathological
painful sensations in one part of the body, the symptoms can
be relieved by increasing the number of stimuli entering the
central nervous system by means of sensory neurones distrib-
uted to other parts of the body, by massage, faradization, hydro-
therapy, etc. It is not impossible that the beneficial effects of
counter-irritation are to receive the'ir explaiuition in a similar
way. It will be the task of the clinical neurologist in the future
to decide from his study of a given case as to the existence of
abiu)rmal neurone-threshold values; lurther, what m-urones are
receiving an excess of stimuli and what neurones are being in-
sufficiently stimulated, and to outline his treatment accordingly.
The
titne of
nent pi
much n
tions of
roiu' do(
of the 1
always o
the stim
trical m(
or how it
iilated, w
an elect r
reaction
'I'lU' (
v.iriabilit
most puz
iias to di
whole essi
iipparatus
that the
birth is a
of res])()iiv
affected b
ergies be!,
tlie peripl
though su
incompIct(
process of
organs liav
that the v;
the extern;
tions of th
dental stri
we iniagiiu
bral cortex
fcrent part
oi'igin of t
to A. fJoldsch
•■^iniicsnei'vi'ii.
Till-: NKrWoNK AS TIIK I'MT.
'I'lic (loctriiic of tlic spccilic ciu'i'jfit's of nerves, since the
lime of its fonmiliitioii by •lolimuieri Miiller, has taken a ])r()iiii-
iient place in nerve pliysiolit^^'y. Tlie view ()f Miiller lias been
nincli niisiinderstood and often misstated, and many modifica-
tions of it have hei'ii sn^r;,fested.* it has heeii left for the iumi-
roiic doctrine to exphiin, if it can, why it is that on stimnhition
of the retina or of the optic nerve, for exiunpk', the response
always occurs in one and the same maiincr; no matter whether
the stimulation be by normal methods or by nieclumical or elec-
trical nioiuis, the sensation of li{j^ht or of color alone is yielded ;
or how it happens that when a "■ (!old point " in the skin is stim-
ulated, whether it be with ice, the pri<'k of a slii-rp toothpick,
an electrical current, or a piece of hot wire (paradoxical cold
reaction of von Krey), the sensation of cold always results.
The constancy of the (|nality of the reaction, (lesj)ite the
variability in the form of the external stimulus, is one of the
most puzzliiii,' of the phenomena with which the neiirolof^ist
has to deal. While some ])liysioloj;isLs would attribute the
whole essence of the process to the characters of the peripheral
apparatus with whi(di the nerves are connected, maintaining
that the jjosition of the centres at which the stimuli arrive at
birth is a matter of little si<j:niHcance, others hold that the sort
of response evoked is dependent entirely upon the ci-ntral re<iioii
affected by the stimulus, which would mean that the sj)ecilie en-
erfjies bel(Mi<; to the centres and are practically independent of
the periphery. It st'ems to me that each of these doctrines,
th()Ui,di supported by distinjfuished neurologists, is necessarily
incom[>lete. Is it not much more likely that in the gradual
|)rocess of development and modification peripheral and central
organs have been correlatively differentiated ? We can not think
that the various modifications of apparatus mediating between
the external [ihysical influences and the most jieripheral [tor-
tious of the sensory neurones of different kinds represent acci-
dental structures whiidi have no physiological import, nor can
we imagine that were the central jirojection fields in the cere-
bral cortex, at which the sensory impulses arrive from the dif-
ferent parts of the periphery, »»f lU) specific signiticaiuie for the
origin of the different sensations, they would present for the
* For a clear and comploto nccoimt of tlio doctriiii' liic rciidcr is idi irtMl
to A. Goldsc'lii'ider's articli': Die Lehre von den specifischen Energieeii der
SiiiiH'snervcn, I5erlin, ISHl.
i,.
'li
'j;
/I
>ntW
'i|
;lli{|i|
2r)»;
TIIM NKUV(HS SYSTKM.
(lilTcrcnt .sciisiitioiis so iibsoliitcly spfcific a structure* 'Flic
piitli()l()j,n<'iil cast's aj^aiii, in \vlii<h direct irritation of tiicsc areas
iti the cortex has caUed forth Icfinite sense i)erce[)tions, speak
for a dire(!t relation of these centres to the specific energies of
the sensory nerves. Odors, images of colored objects, of mus-
cular movements, and of sounds have been experienced hy indi-
viduals sutlcring from the pressure of cysts and other bodies
upon the correspoiuling cortical sense areas.
The (piestion is still obscure, nor have we much promise
that it will speedily be satisfactorily explained. \'on K(il!iker,f
in a discussion of the physiological functions of the elements
of the brain, thinks that all nerve cells possess in the beginning
essentially the same function, and that the manifestation of
function depends entirely upon the numifold external influences
or stimuli which affect them, and ui»ou the many possible modes
of responding to these excitations.;);
*" Die haii(lgieiflit'hen Unlersehiwle iiii UttU der Ccutrulwiiiiluiigen, der
liiiide (Icr Fissuni cak'ariiia, des (Jynis hipixK'aiiipi. etc., .sind sflion laiige
bekaniit, wemi aiieli suiiderhariTWcise uiciu reeht yewiirdigl." 1'. Fleulisig,
Geliirii und Seele, II Aufl., Aiini. iJl.
t Op. fit., 15d. ii. S. 803-«i;}.
X "Sodrilngt sicli docli zuletzt die reberzeugung zwingend auf, dass alle
Nervenzelleu von Ilausc aus wesentlieh dieselbe Fuiiktiou besitzen, und dass
das Inslebentreten dersolben einzig und allein von den inannigfachcn
iiusseren Einwirkuiigen oder Keizeii, welehe diet^elben treffen und von den
vielen Mogliehkeiten einer Beaut wort uiig dieser Erregungen abhilngt."
CIIAITKR XMI.
Tin: vriitoN'i: as a imt ok nkuvoi's riNcTKiN.
A
I'girlici|mtiiiii of nil pnrts of thi^ iii'iiroiic in llii' iiIh'Iidiiiciiu of ii'ritiihility —
Fiiiictidiis nf the ci'U Ixiilics — N'icws regard in;; llii' luitiirc of ilu'
(It'iidrilcs.
With the concc])! we liiivc i^'iuikmI of the nciiroiu' with iill
its piirts, lis ii I't'U, and of tlio unity wliicii cliaracti'rizi's tlie
various steps in its metal)()lisni, it would almost seem idle to
devote time to tli<' (|uestion of the existence of a unity in
nervous function ; the latter would appear to be a necessary
corollary, and i should not discuss this topic at all were it not
•^hat some of the most distin<j;uished investi<;ators have assumed
that only a part of the neurone is concerned in the actual nerve
functioji, in the plu'junuena of irritability, in the transmission
of im])ulses, and the like.* All arc aj^reed that th(( axoiu' —
the axis cylinder of the nerve iibre — with its endinj^s, is active
in the coiuluction of impulses, but concerning the nerve
function of the cell body and of the dendrites there has been
much controversy. Rccallin<r for a moment what was said at the
beginnin<f of thesi' remarks rcffardiuf:? the position assumed by
(lolgi as to a din'use nerve network, it will be rcmend)ered that
he excluded iu the spinal cord the dendrites and the cell body
from the reflex arc. The sensory impulses, he thought, passed
from the sensory fibres directly through the til)ril reticulum
out along the side fibrils to the axoncs of the motor fibres, and
thence alcmg them to the muscles. Accordingly, he doubt(Ml
the possession of nerve function by the cell body and dendrites,
and assumed that they were set apart to act solely as nutritive
structures. That the cell bodies themselves are concerned
directly in the nerve function can now siiarcely l)e doubted l)y
any one, hardly even by Oolgi and Nansen, since the intimate
'^11
* Irritiibility und conductivity, iis lias long been known, are not o(jiiivii-
Icnt terms.
IS ' " , 257
1^
r
I,
r
i!
Ill
liaS
TIIK NKIJVOlS SYSTKM.
rcliitioii of jixoiir :iii(l Icrminiils to tin- pnttuplnstii liiis lu'cn
(Icjirly ticmuiistriitfil in (('rtiiiii iiistiiiiccs. 'riic (»ri;;iri of tlio
itlcii «»l' till' non-part icipiil ion ol' I lie i rll l»oily in I lie prop!i;.'iilion
<»f nerve ini|Milsi's ciin l)c jiccoiinlcd for l>v tlic jippiircnt cxist-
vuw of nicclianistns for cxclutlin",' it from the ilircct path of
the fiirrcnt. A prr;,'nanl t-xainplc (dlorcd was the arran/^'cnicnt
ill tlic spinal j^'aii^'lioii cell. l''or a lon«,' liiiii' it was licld l)y
many lliat the 'I'-sliap^d process wliicli l)n»ii<,'ht the pt-riplicral
into a direct line with the central axoiie was for the purpose of
ciittiiif^ olT the cell hody from the conduction path, 'i'liis idea
was lu'ifatived hy the demonstration of Wiiiidl * of a delay in
the passajj;e of the i;ii|tiilNe correspoiidin;,' to its |iassaj.'e t hroii;;h
the spinal }xaiijj;lion of 0.()():{ «tf a second, a result which has
heeii conliriiied and extended hy the evieriiiieiits of (iiid and
.losepii u|)oii lheva<jiisof raithits. Moreover, the relations of
tiie processes to the cell hody in the coidilear and vestiludar
/fanjxlia of human liein^^s, as well as those in all the sens(»ry
jian^lia of lishes, necessitates the passaj^e of the impulses di-
rectly throiifjh the cell hodies. And, lastly, the pliysiolojfists
who have studied sindi centres, as, for example, that <,'overnin<j;
respiration in the medulla, and who assume that excitation of
this centre can result from the direct ehemiciil action of jj^ases
in the hlood, will not porinit us to helieve that the ^n-oiip (d"
cell hodies inakin<f up the centre is un;*oncorne<l in nervous
nu'cdianisms.
'riiere has heen iiiiich controversial writinj^ upon the func-
tions of the dendrites. The arjiuments in favor of the dilTerent
views have Iieen ahly niurshaled and criticised hy hoth von
Kcilliker f and von Lenhossek.l On account of tlie fundamental
im|»ortance of the topic it will he necessary to consider i)rii'lly
the main points hearin«f upon it.
A inainstay of the (iolffi school was the siipjiosed direct
attacliinent of the ends of the d( ndrites to the glia cells and to
walls of the hlood-vessels. 'IMie siip])orters of the "nutrition "
view held that the dendrites thr()u<ih their apical attachments
represent the direct paths for the introduction of food materials
* Wuiult, \V. rntorsuchunijeii zur Jlceliaiiik di-r NVrvou lunl Norvfu-
centrcii, 8vo. Sluttjjiirt. IHTI-'Tfi.
t Von KollikiT. Il.imllnuli dcr (Jewebolehre des Menscheii, Hd. ii, S. 58,
111-115. 1'2(!-1'28. GS:{, (i84.
} Op. ciL, S. i;55-143.
I
.1 [
11
ill
TIIK Ni:ri{(»NK AS TIIK INIT.
25!)
from I 111 Moo'l-vcHscls into I lie nerve cells Now, wliile the
(lireet iittiieliiiieiit of manv of tlie |iroeesses of <,'liii cells to tin*
walls of tlu blood-vessels ii|»|Miirs to liiive l)eeii definitely
proved, there is no evidence iit nil tlint jinv such iirnin^jenient
commonly exists for the dendrites of the nerve cells, .\ccord-
injr to von Kolliker, the only iittcinpt to picture such a relation
is that of Sala.* This example «d" failure of the dendrites to
end free must l)e looked upon as an unusual observation, l-'.ven
if it bii coulirmed, the experience of every one who works with
the silver method must convince him that sucli a relation is
hi<(hly except ioiud. Moreover, st udies upon the histoi^'cucsis of
the mM'vc centres reveal no distinct reciproeiil relations between
the blood-vessels ami the dendrites.
This connection \\\l\\ the blood-V(!8sels wasthou;^dit by (iolj,'i
to be the true explanation for the existence of the forests of
dendrites whi(di pass out toward the surface of the cerebellum
and cerebral cortex, and of the dendiites which in the spinal
cord run out in no inconsiderable numbers into the white
matter for sonui distiiiico, and iji some animals (for exarnple,
certain reptiles) even to the surface, forming? a nuitted feltwctrk
upon the exterior of the cord. Could any more itlausil)le ex-
planation be jfiveii thaJi that they, like the roots of trees draw-
'\u<i juices from a distance, pass outward to obtain nutriment
from tiu' iilood-vessels of the pia ?
That iidciulritic cells I'xist, has been adduced na an arf^ument
aj^ainst the nervous function of the dendrites and in favor of
their nutritive function. So obvious a fallacy is hardly worthy
of consideration.
Sonte liistolofijists, who concede* that many of t he (h'tulrites
have to do with both nervous and nutritive activities, believe
that dendrites may exist which ])ossess oidy one (dass of these
functions. Thus, von KcUliker, wliile he inclines to the view
that many of the dendrites are concerned in conduction,! is by
no means willing to deny that there are some of them \vlii<di do
not play such a part, but whi(di serve oidy to aid in the nutri-
tion of the cell. He emphasizes the stad^ment that all the
*Siiliv, L. Zur foinereii Anatomiedt'sgrosscii Secpfcrdefiisses. Zlsclir. f.
wissciiscli. Zool., Miiiicli. ii. Lcipz.. Hd. Hi. Taf. v. F'xjx. (!.
f " Fass(>ii wir idles ziisaiiimcii, so scheint, wic die SiK'lieii jclzt litigcii,
(lie VVagschale doch in hohoin Grade zu (Juiistcn dcr iicrvIVscii Natur dcr
Dendriteu sieli zii iiPigL-n." IbiiKlbucli dcr (icwcbL'lclire, Hd. ii, S. IK!.
/i
"Ti
: t
IN
» i
I
li!'
1
I
liC)!)
TlIK NKIJVors SYSTKM.
])liysi(ilo<ji('iil functions of tlic s|iiiiiil conl cuii be (Mitircly satis-
factorily cxijlaincil witiioiit calliii^f in the aid of tiic den-
drites.*
There is sonic force in the ol)jection tiiat tiicre are den-
(h'ites so situated in tiic nervous system that tliey ajiparently
can not come into conduclion-relioion with structuri's heh)njf-
in^ to otiier ncnroiu's. Many of the examples which have heeii
hroujflit forward lo illustrate this point have not, however, stood
the test of invesiij^ation. 'IMuis, Ramon y Cajal and ('. L. Salii
have demonstrated in hatratdiians collaterals from the fibres of
the wiiite funiculi in the spiiud cord which run out toward the
])eri])hery and even to the surface of the spimil cord to uun<;h>
withtlic plexus of di'iidrites in that sit nation. I thcolfactory
hulh, however, and in Ammoirs horn and the fuscia deutata,
there are dendrites which appear to have no direct relations
to the terminals of collaterals or axones of other lU'urones. At
anv rate, su(di relations have not yet been ju'oved. Kven von
Lenhossek, who along with van (ielnuditen ami Kamon y Cajal
is one of the stron<j;est supporters of the x'ww that many of
the dendrites are conductors, fifrauts t that to assert that the
disposition of the dendrites in the lu'rve centres depends en-
tirely upon the establishment of functional relations among
dilferent neurones is going too far. He argues that if this wore
the sole determining factor the organism could have gotten
along with much simpler arrangements than those to be met
with in uiany jiarts of the central nervous system — for exam-
ple, in the molecular layer of the ccrcix'llar cortex, lie would
rather assume that the excitations occurring within m^rve
cells are in some way favored by the fact that the proto-
plasm of the cell is split up into a Miiud)er of fiiu' processes —
the deiulrites.
Let us turn now to the tlata which favor the assumption
that the dendrites are concenu'd in nerve function as well as in
aiding in caring for the nutrition of the neurone. The nn)st
conviiu'ing evidence of nerve function in (len<lrites is that
otfered by the structure of those curious bodies, the olfactory
glonuM-uli. The view advaju'ed by Owsiannikow J and by
* Op. (it., s. vm. \ ()/'. <■!/.. s. ii'j.
J Owsiiumikow, 1*. rdii'V <lio feiiiiMV Striictur dcr Ijobi olfiu^torii dor
SiiiiKctliifrc. .\rcli. f. .\iiat., IMiysinl. u. wisscnscli. Mi>i!., l,,-i|)/. (ISOO), S.
4(1!)- 177.
'I'lIK NKllfoNK AS TIIK I NIT
-»il
Waltt'f,* that tlic lil)r('s <it' tlii' olt'acturv nerve on entering I lie
bull) from till' ro^io (tlfacloria heeonie directly e()nliniH)ns with
llie |)roeesses of the lari^e and small nerve cells ol the '^vi\\
matter of the olfactory lohe, was sliarj)ly contestetl lty(lol<,n,f
who asserted that between the liiii' librils into which the olfac-
tory nerve libres break u|i on entering the <j;lonieruli and the
bejxiniiinjjcs of tiie protoplasmic processes id' the cells of the ^ray
matter no union i-an he demonstrated ; nay, since sometimes the
protoplasmic processes stain wlien the axis-cylinder processes
fail to take the dye, and ricr rcrsa, ))robably a (diemieal ditl'er-
ence between the two sets of tibrils exists.
Ramon y ('iijal,^ f'"<'m a car(d'id study of tlio ^lonwruli with
till' osmo-biclironnite method, came to the eonelnsion that the
only possible ^latli for the olfactory nerve impulses is from the
terminals of the olfactory tibres in the <,domcruli to the den-
drites of the mitral cells, and aloii'^ these to the cells whence
they follow their iixones into the olfactory tract { l"'i,ii. l.')T).
»
lese observations and views were eonlirmed in a lar<re niinil
ter
(»f animals by van (iehueliten and Martin, || as well as by von
Krdliker.'*' The last states (>mphat ieally (I) that the dendrites
can assume the conduction of nerve impulses and {'i) tliat the
transference of nerve impulses from one neurone tt» another
can take jtlace directly from fibre to fibre, a direct influence
of cell body uiioii libres or of fibres upon cell bodies not beiiij;
'ssential
The existence of anatomical relations which render neces-
sary the assumption of a i'oiidiictiii<j; capacity for the dendrites
has been further demonstrated in the cerebellar cortex by
1
rti
V. !
//
t 1
* Walter, (i. I'clptT dcii rt'incrcn Un\i dcs I5i
oiriiclui'ius. Anil. f.
nil. AllJlt., etc.. I?
l!(l. xxii (ISC. I). S. :Ml-'J."i!).
t (lolgi, ('. Sulla fuia stfuttui-a del liiiHii (lU'iitterii. Iviv. spiT. di frciii-
ai., Hof^gio-l-'iinilia (1875). vol. i, pi). 4().')-425.
I Ifaiiu'iii y Cajal. S. Oriufii y tt'rmiiiacii'ni dc las I'liras iicrviosas oUac-
torias. (iiiL'. sun. ill' IJari'i'l., vol. iii, IHIIO; also Kl I'lU'ofalu ili' Ids reptiles
ISarcolona, IHill.
*• (iolgi's (iliscrvation of fine axoiies enlcriiif;; liie (ilfaeli)ry njliiinoruli,
iillier than those of the nervi olfaetorii, has not, so far as i luiuw, lieen con-
firnied l)y othiM's.
II van (ieluichlen. A., et Martin, .f. Le Ijullie ulfaetif rlie/ (|Ui'I(|nes
nntnuiiiteres. baeollide, i;ouvaiti, I. vii, I'ase,
^ von Kiillilicr, A. I'elier den fe
i'l
). "JO.)-
Mi Hau lies jtulims oiraelorii
Sitziinf^sii, d. pliys.-ineil. (iesellseh. zii Wiuvl)., .lahri;. (1S!(','), No. 1, S. l-.l.
If
\|
mm
I
I
i^lil' I
2(\2
THE XHUVors SYSTEM.
Riiniuii y Ciijiil;* in Uio optic lolx^ of birds (Fig. loS) ])y van
(iehuchten ; f in the distribution of the axones of tho mitral
Km;. 1
/;
111
IK
Sll
of
)7. — Sclicinc of the olfiictory iii)piiriittis of niiiiiiniuis. ,(, the olfactory lolx?;
olfiictory liiill) ; r, ciirtiliijii' of tlic t'liiliryoiiic crilirifonii iilatc ; I), nasal
iicdsa ; II, siip|iiiitiiiK it'll ; ''. pfiiplK ral olfactmy nniroiic ; <■, arliorizatimi
ail olfactory nerve lihrc in llic jrloiiKTiiliis of the olfactory Imlli ; il. small
I've cell ; (', mitral cell ; li, so-calleil "granule" : (/, larjie st<'llale cell with
Dit axoiic (/) tirniinatiu}; in the molecular layer; .;, arborization of lihres
centi"al orifiin. (After liiinion y Cajal.)
cells of the olfactory lobe by Callejn ; J and in the retiTui l)y
Dogiel.* There can, therefore, be no (loul)t that certain of the
dendrites are capable jit least of receiving excitiitions and of
l)laying a part in their further propagation. Kiinion y Cajtd,
van (iehuchten, Itetzius, and von Lenhossek htive therefore en-
deavored to extend the view so as to make it hold in general
for all dendrites, and have assumed that tho most common mode
* Ramon y Cajal, S. Significaciou fisioluj^ica do liis expaiisioncs pmt.o-
lilasinalic'iis y norvosias do las (('liilas do la siistaiicia gris. Rev. do cioii.
mod. do Hiireol. (1801), Alio xvii, j). (IT!!.
f vail (loliiiolitoii, A. iia structure dos lobos optiijiios oho/ remhryoii do
poiilet. f'cllnlo, ijierro ot Louvain, t. viii (1892), fasc. i, pp. l-4o.
\ f'alloja, ('. Tia regii)ii olfacioria d<d oorohro, ^Nfadrid, 189:$.
* Dogiol, A. S. l']iii liosoiidoror Tyjiiis von Norvoiizellon in dor inittloroii
gaiigliiJsen Schicht dcr Vogel-Retina. Anat. Anz., Jena, Bd. x (1H95), No. 'i'-\.
S. 750-700.
II
I
THE NKURONK AS THE UNIT.
203
of transff^ronrc of a iiervo oxcitutidii from one iieuroiu; to ji
seooiul is by rneiins of the contiiet of tlut tcrniiiials of an axone
of the fornuT with the (U'lKh'ite.s of the hitter, a coiichision
whieli woukl seem to be scarcely warranted l)y the facts at pres-
//
Fifi. 15S. — Section throiiKli ttic optic lolic of the cniliryo chick. i.Xt'tcrA. vim
(iciiiiclitcii. Cellule, Liirre el Liiiiv.iin, t. viii, isit^>, IM. i, h'in. t. i In the
cxteriiiil layer ,( ;iie re|)resente(l the teiiiiinals ol' the lilires oC fetinal origin ;
in the layer It are shown several nerve cells ol' the iniildle /.one of the optic
lohe ; fi\ zone of peripheral nerve tihrcs ; n and h. superficial aihorizalions ;
(•and (/, deep arhori/.ations ; c, reclanf;ir <r arhorizations ; /, ciihoidal aihori-
zatioiis. The nerve cells show internal dendrites nianiColdly hranchcd, and
a larye peripheral dendrite which leriniiiates at dillerent levels in the outer
layer, souietinies i /.■ > hy a horizontal arhorization at the level ol' the deep
retinal arhorization. The axone arises from the peripheral dendrite and
runs throu};h the middle ia.ycr, ^iviuK olf numerous collaterals, ('.
':c.
■ > J
J 1
eut estal)lisli('(l. That it is one niethod of transference is cer-
tain ; but that tliere are others, for e.xaniph', throuffh direct
i'
f
I :
[:
204
TlIK NHUVOrs SYSTKM.
contact or concreaconco of iixoin! terminals witli the protc])lasm
of tlu! cell body, all grant.
It may Itc uoitli while to i)oint out Just licrc a certain fallacy of
{jencrali/atiori (o wliicli. curiously ('iiouj^!i. attcutiou appears not to
have been called. Kvidence has Iwcn adduced wiiich demonstrates
indubitably that in certain parts '" the nervous system the
anatomical relations are such that a cond;'ctin<^ function for the
dendrites must be admitted. This proof was brou{,''ht forward as
one of the means of demon.stratinj;' the nervous function of the
dendrites. But some writers appear to take it for granted as a
necessary secpience that dendrites for wliicli no sudi aiuitomical
rehitions are demonstralde pos.se.ss no nerve function. If this were
souml reasoning, we should have to a.ssume that the transference of
impulses from one neurone to anotiier made up the sum total of the
nervous functions, an absurdity too obvious to need further discus-
sion. We have not the right to draw our deductions from any one
factor to tlie exclusion of all other coexisting intluences. It is
sui-ely easy to conceive of a particii)ation of the dendrites in the
nerve functions of the neurone, even if they stand in lu) direct rela-
tion either of receiving or discharging to another neurone or set of
neurone.s. Indeed, granted that one ])ortion of a single cell, as we
believe a whole neurone to be, po--M•s^ s nerv(^ fuiuition, the onus of
proof upon the (pie.stion of the ature of another portion of this
cell — for example, the dendrites lies with those who deny the
nervous function, not with those w maintain it.
Now that the cell body of the neurone is known to possess
nerve function, the fact that the a.xone often comes off from a
dendrite instead of from the cell body is further evidence in
favor of the identity or at least similarity of function of cell
body and dendrites. This conclusion would agree strikingly
with the morphological resemblances revealed by the method of
Nissl. Further, if anaxo'ies are to be regarded as nerve cells,
as seems almost certain, the dendrites must surely possess nerve
function.
That the a.xones are concerned in the nerve function of the
neurone has, so far as I know, never been (|uestione(l. It is
generally believed that in the conduction of the excitations
there can be no transference from oiu^ jieurone to another
except in those parts in which the myelin sheath is not present
— that is, for the majority of neurones, so far as the axone is
concerned, only in the region of its terminals and possibly in
the short Jion-meduUated portion immediately adjacent to the
t
llli
THE NKUHONE AS TIIK IXIT,
2r.r.
ncrvo cell. This statciiicnt is i>(|Uiillv true of tin- colliitc'rals,
for, as Flcclisig * has siiowii, these bniiiciu's, at least in the
cerebral oortex, are, like tlie iiiiiiii axones, jirovidiMl with
medullary sheaths. We have iiiduhitahle evidence, too, that
the majority, if not all, of the c(*Ilaterals of the dorsal root
fibres within the spinal cord are niedullated. The side iibrils
of (iol^i are non-medidlated, and from the studies of von Len-
hossek, Apathy, Held, and iieihe ma\ probably be important
a^'ents in the transference of itn|»idses from neurone to neuroiu-.
The relation in which the side Iibrils staiitl to the neuropilum
in invertebrates has already been referred to.
/I
* Flwlisifj, P. Ufbcr cine ni'ue Fiirbiuiysiiictlitxle dos (iciitralt'ii Xcrvi'ii-
systems imd dcrcii iM-f^clmissi' l)czii};licli dcs Zusuniiiu'iilitDigcs von (ian-
{^licnzellon iind Xcrvi'niii.sern. Arch. f. Anat. ii. I'hysiul.. Lcijiz., I'liysiol.
Abtli. (18H!)), S. .%?.
U
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CIIAI'TKR XMIl.
ox THE DIRKCTIOV OF rONniCTIOX IN Til K XF^l'UOXKS .VXD
TlIK TIIKOKY OK TIIKIK DYXAMIC POLAKITY.
Oiroptioii followt'il l)y iicrvc itn|iuls(s in their ]iass«i^i' tliniuj,'li iiciiniiics —
CflluliiR'tiii iiiul t'ol!ulifiij,'.'il coiKliiftioii — 'I'licory <if tln' ilyniiiiiic poliir-
ity of the nei'vc elements — (^lU'sticii (if imssibility of eoiuli 'tioii in both
directions in axones and dendrites.
Wi: liavc now to deal with the ciucstion of tlie direction
foUowed by a tierve impulse in its passajje throtijrh a neurone,
and have to eonsider tiie evidence for and ii<fainst the view tiiat
the impulses in a given viiriety of cell processes take always
the same direction. Tlie hypothesis that in the neurone the
dendrites represent the apparatus for receiving nerve impulses,
conducting always in the direction of the cell body (cellulipetal
conduction), the iixoiic.^' being tlie discharging processes con-
ducting always in a direction awiiy from the cell body (celliilif-
ugal conduction), advanced first, I believe, by van (Jehuchten in
April, 1K!)1,* has been strongly advocated also by Riimon y Cajalf
in an article in which hi' deals with "the theory of the dynamic
polarity of the nerve elements." Retzius J has declared also in
favor of tins view, and it has been tidopted, though in a some-
what modified form, by von Kolliker, Waldeyer, von Leidiossek,
and others. In the embryologica! lonsidenitiims of His and of
Midi it met with approbation, since (f priori nothing could be
more natural than tiiat tlie processes developed upon the end of
the cell originally directed toward the outside of the ])ody
* van (ielincditen, A. La struetiire des centres nerveux. T-a inooUo
epinifere et le cerveiet. Cellule. Lierre et Lonvi',;ii, t. vii (IHiU). p. !0t.
+ Hanion y Cajal, S. Signifieaeion flsiologiea de las expansiones pro-
toplasinaticns y nerviosas de las celulas de la suslancia gris. Hev. de eien.
nied. de Marcel., vol. xvii (IH'll). p. {u'.\.
X Retzius. Ueber die neneren Prinzipi(>n in der Tichre von der Ein-
riehtnng des sensiblen Nervensystenis. Hiol. Untersiich.. Stockholm, n. F.,
Bd. iv, 1893.
26G
I
1 ''*;u
•i 'I,.
TIIK NKITRON'K AS TIIK U.VIT.
207
should serve for the rcccj^tion of stiimili.* Tlu' uctiiul proof of
(•('lliiIi|H'tiil contlnctioM in (Iciulritcs is cstiiblislit'd l)y tiie obser-
vations ])reviously mentioned, wiiicli demonstrate tlieir con-
duct in<j capacity ; above all, by those bearinj; upon the structurrtT
of the mitral cells and the relation of their dendriti'S to the
olfactory glomeruli. The f^alvaiionietric experiments of Mis-
lawsky f have led him to sui)port tiie doctrine of cellulipetal
conduction in dendrites.
That the axones, at least when en<^a.ijed in those of their
functions with whi(di we are ac(|uainted, conduct, as a rule,
cellulifuji^ally is imnuHliately apparent. Among other examples
we have the i)assage of impidses along the pyramidal tracts (»r
along the motor nerves from the ventral horns to the muscles,
or, again, in the dorsal funiculi of the s})inal cord or in the
optic nerve. From the nature of things in motor neurones
the cellulifugal impulses passing along the axones are also cen-
trifugal impulses; while in the sensory neurones within the
central nervous system the cellulifugal impulses in the axones
are, as a rule, centripetal. This is not, however, tantamount
to saying that centripetal impulses are always descending,
and that centripetal impulses are always asceiuling, although
this holds as a general rule. An example of an exception is to
be found in the descending liml) of the Y-shaped divided dorsal
root lii)re whicdi passes downward to terminate in the gray
matter of a lower level and is undoubtedly a centripetal fibre.
Are there exceptions to the law of cellulipetal coiuluction
in dendrites and of cellulifugal conduction in axones? This
question, according to our present knowledge, must be answered
in the athrmative. In those dendrites from whi(di o(!casionally
an axone takes its origin it is obvious that the conducti(m in
the portion of the dendrites between the general cell body anil
the axoiu' hillock must be cellulifugal, not cellulipetal, a diffi-
culty of iu)nu'n(dature which can be obviated by ado})ting the
suggestion of von Lenhossek, who recommends describing the
impulses i'l dendrites as being a.vopefal rather than cellulii)etal.
But in this way we are thrown on the other horn of the
i
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*('f. Mall, F. P. IlislogoiR'sis of the Ui'tiiiii in Aml)lystoin!i ami
Nec'turiis. J. ^[(.rpliol.. Host., vol. viii (18!):!). pp. 4ir)-4:i','.
t ^lislaw.sky, \. Sur lo role physioloijifiiic ties deiidrili's. C'ompt. roml.
.Soe. de bid., Par. (1895). 10. s., t. ii, p. 488.
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208
TIIK NKK vol's SYSTKM.
(lilcmma when we ((iiisidtT t lie (lircctioii (if coiiductioii in the
(Iciidritcs of iiii aniixoiic — for cxiiiiiplc, in tlic .iiiiacrinf ct'lls
of I 111 ret ill!!. Wlicrc there is no axoiie it would he ahsnrd to
spi'ak of axopetal impulses. 'I'he arj^aiineiit that there arc
(h'U(hMti's \vhi(!h stand in no rehition with processes of other
lunirones wliich wouhl perruil of any transference of iinpulscH
makes aj^ainst the (h)etrine of tlie universal cellulipetal con-
duction of dendrites. Further, if there is ever a transference
of impulses from one neurone to another hy means of the inter-
woven dendrites of two neurones, a view which von lieehterew
stronj^ly supports, it is obvious that with a jjiven impulse the
direction of tlie conduction in one of the sets of deiulrites must
be cellulifuffal and axofuf^'al. \'on Mechterew, in corroboration
of his liypothesis, (k'scribes tlie intimate relations of certiiin
dendrites of the two halves of tlio (!ord in the ventral commis-
sure, ami of those of tlu^ anaxones in the olfactory lobe with
those of the mitral cells; further, he adduces as instances the
dendrites in the molecular layer of the cerebral cortex, and es-
pecially those of the nuclear layer of the cerebellum, interest-
ing as the hypothesis is, there is, as yet, no jiroof of its truth.
>■' early all writers have a<freed that in vertebrates in the
typical monaxones the conduction aloiifjf the axones is (udlidif-
ufjal. In the diaxoiu's, however, the same rule need not hold.
If we look uj)on the spiiuil ganglion cells as diaxones, then, oh-
Fl(i. If)!*. — Siiiiial cord (iriiiiiplii<i.\iifi. (Al'lcr Kctziiis.) iih\ nutcf itiiKlc ol" sjiinal
cord; mi. iiHiliiiii line; .v. sensory nerve niols; »c'. liijiolar niiUKlioii cells,
tlie iniiiii processes of which run loiifjitudiiially ami <livide <licliotoinoMsly
(T-sha|>ed I. sendiiif; one hninch into a sensory root.
viously, the direction of the condtiction of the sensory impulses
in the pcriphi'ml axone is cellulipettd ; in the central iixoiie,
cellulifugal. Those who hiive committed themselves to the
doctrine of universal celliilifugiil conduction in axoiu's btive
denied !hat the axis cylinder of the peripheral sensory nerve
fibres is i*' ally an iixone, assuming it to be rather dendritic in
II
TIIK NK IfONK AS TIIM INIT.
Fifi. KiO. — Spinal curd of Min|iliioMis. i Al'trr Hct/.iiis. i mi. inidiaii linr ; iih-,
(iiilcr aM!,'lr ciCspiiiiil ronl ; s, sriisory root. A liitlicr laru*' iimltipolar rcll is
shown, till' axonr ol' wliiili enters intii a sensory rout.
the iii'riplicnil fibro is, iisu ruU", longer tliaii tluMicntral ; for thu
cochU'iir iind vpstibultir giinglia the pcriphcnil tihrc is the short(!r,
ami luTo the pnxH'Ss passing to the periphery is of smaller
ealil)re than that of the eentnil iihre. I tiik(! it tluit we niust
a(!kno\vle(lgo that, though enihr^'ologieally a dendrite, the periph-
eral sensory fibre in the adnit is histologically' an axone, and
the passage of impulses from the periphery to the centres must
bo granted as tin exanij)le of (H^llulipetal conduction in an axone.
In amphioxus, an animal which p()ssesses no spinal ganglia,
Retzius f has shown that the sensory impulses are re(!eived !)y
the telodendriojis of axones and (conveyed along axonos eellnlip-
etally to the nerve centres, a form of sensory apparatus very
commonly met with in invertebrates. In amphioxus two varie-
ties of cells send axoiu-s into the sensory roots, bipolar cells
(Fig. 150, n z') and multipolar (sells (Fig. KiO) (Smirnow, Ret-
zius, von Lenhossek).
* Tlip sufjfil'cst ion that (ho poriplicriil sensory filtro is a dentlrile was, I
bi'liovo. first mailc by l{«inoii y Cajal. in IHHi), in ati (irticlc entitled Cdii-
nexion f^eiionil de los eloinontos nerviosos. which uppcanMl in La i licinii
practicn, ^bidriii, in ()(flol)or of tliat year.
t Uotziiis, G. Ziir Kenntniss (it-s eontraleii Ncrvensysteins von Amphi-
oxus lanceoiatus. IJioi. llntcrsui!!!.. Sloekholni, n. F., Htl. ii (1891), p. 2!).
I ;
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270
TIIK NEHVOUS SVSTKM.
t
' II k
The fiift that the optic nerve ('(Hitains axones whoso rolls of
ori<rin are situated not in the retina hut in tiie lirain (corpora
{|Uatlri<jeiniMa) is not, as some think, proof of ceilulipetal con-
duction in axones. 1 can aoe no reason for not helievinj; that
contrifujjal impulses pass from the brain to the retina, indeed,
now tiuit we know what an enormous Mund)er of neurones are
situated witiiin the retina, it wouhl l)e surprising' were its ele-
nu'iits not in some way under the control of a frovcrniuf,' centre
in the central nervous system; and d /irinri the centre most
likely to possess the jmwer would' he one of the three which (irst
rect'ive the centripetal impulses from the retina, namely, tliat
which we know to he also the local seat of government for the
movements of the eye muscles — the superior colliculi of the
corpora (|uadri|femina. That these eentrifu<j;al iihres of the optic
nerve represent the apparatus concerned in the ohjectivization
of reci'ived sensations — /. r., in their projection outward — an
idea suf^f^ested by von Hechterew, does n(»t seem to me to be
})roljable.
The arguments for cellulifugal coiuluction in axones hold
also for their mednllated collaterals. The hyi)otiiesis has lu-en
put forward hy von Lenhossek * that (lolgi's distijiction be-
tween non-medullated side fibrils and true mednllated collaterals
is of definite physiological significance. He thinks it very
probable that the side fibrils act as axopetal conductors, the
true collaterals alone being cellulifugal as regards direct ioji of
conduction. lie advances as examples the relations of the side
fibrils on the axones of the ventral horn cells of the cord, the
I'urkinje cells of the cerebellum, and those described by Ramon
y Cajal and van (iehuchten on the axones of the olfactory
mitral cells. He would designate the side fibrils then as axo-
dendrites (to distinguish them from cytodendrites), and the
true collaterals as paraxoTies. Von Lenhossek's personal stud-
ies, particularly those dealing with the relations in rodents (Fig.
l(il) of the sensory collaterals to the side fibrils given off from
the axones of the ventral horn cells, are indeed strikingly sug-
gestive of the exercise by the side fibrils of a receptive function
for impulses. As a result of his own studies van Ciehuchtent
has opposed this theory, and I must agree with von KoUiker
that up to the pi'esent time a ceilulipetal conduction in the col-
* Op. ciL, is. 129-134.
f Cellule, t. xi.
inikr. Aimt., I!
Till". NKIMJONK AS TIIK rXIT,
UTl
liitcruls (side tibrilH) is no better ]»rovi'(l than is ccliulifugal
coiuiiu'tion in the dendrites.
If the Htiidies of Apatliy and Hitiie be contirnied, and it bo
true that the fibrils dctnonstral)!!' l)y tiicir niethods In- es]u'cially
(lilTerentiatcd Tor the purpose of eonductiiifr impulses, a partiei-
jiation of all parts of the neurone in the plienoniena of eondiic-
l''l(i. Ifil. I'ortioii of siiiiiiil ((inl of iic\\-l)cirii nil>l>it stiiiiicd l),v tlif cliroiin-silvfr
iiictliod. /(, liiH' plfxiis fornicd of (iol«i's ,si<lc liln'ils from tlit- iixniics of vcii-
fral lioni cflls at tlic vciilriil iiiarKin of tlif v<ntriil liorii ; /*, coimiiissiinil
iixoiic with U>un side lil)rils, <■. ( Al'tcr M. voii Lciiliossrk, l)cr fciiicrc I{iHi
d«'» NiTvi'iisysU'ins. etc., II Aiill., IWtr), S. 257. Fifi. :W. '
tion must be granted, for tliese fibrils are limited to no singU'
portion of the neurone. Moreover, since the same fibril cau
sometimes be followed runniTig cellulipetally in one branch of
a dendrite and eellulit'ugally in another branch of the same den-
drite (Hethe), it is obvious that, if the fibril conducts, the den-
drites must carry both cellulipetal and cellulifugal impulses.
A most interesting and difficult experiment performed by
Bethe* must here be referred to. This inves^i'jator, working
at Naples in November, 1S!)(>, isohited the neuropil of the sec-
ond antenna of Carcinus — in other words, he removed the gan-
glion cells of the neurones supplying the antenna, but left their
processes and side branches. He proved that, even in the ab-
* Bethe, A. Das Cciitralnervensystcm von Carcinus Maenas. Ein
anatoinisch-physiologisolier Versucli. I. Tlieil, 2. Mittheiluiig. Arch. f.
inikr. Auat., Bonn, Hd. 1. S. 589-639.
.,^«<. •• '
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273
TIIK NMHVOllS SVSTKM.
«nii<'<« of the pcrikiirvoiis of (he iiciiroiit's, llcxinii aiul cxtt'iirtion
ciiii be rt'llcxly prodiict'd — iippaiciilly aii iil)soliitt' (Icinoiirttru-
tioii tlijit lu'uroiics cjiii tctiiporiirily contimic to I'litictiou in tlio
entire! iibscncc of tiicir cell bodies. In a still Inter article,* as a
result of his studies of the primitive tihrils (Apathy), IJeIhe eon-
eludes that the explanation of nis fundamental reflex experinu'iit
irt to 1)0 found in the relations which the lihrils hear to the mech-
anism. Tlieso ndations are illustrated in Vi^. Itl".*. When Bet ho
I'm. Iti^.— Si'lii'iiiiilic (IniwiiiK tci illiislrulc tlic com'sc of tlic |iriinitivc lihrils of
till' ri'ccptivi' iiiid iiiotof clciiiciits of the sccoiiil aiitciiiiii of i 'iO'ciiiiis Macims.
I Aflir A. iicllii', Anil. f. iiiikr. .Viml., Hoim, M. li, ISits, Tiif. xvii, Fin. 3.)
Ilhif priinilivi' fitirils coiiiiiiK fmiii the "' icccplioii iuiir.s" on llic siiiliuc of tlic
Ixidy 111 Ilif cintriil oi'naii. Hiil llic |iriiiiitivc lilirils };oiiiK to the iiiiflcus.
Uliiih- oilier liliiils.
A'. '(. p.. iiciiropiliiin aiiliiiiiaiii posttiiiis ; .V. I., iicmiipiluiii tcKuniriiliirii ;
.V. 11. I., ni'iiropiliiin aiitciinarii latcrali' ; .V. n. m.. iii'iiidpiliiiii aiili'i iiarii
iiii'dialc; /(. motor priiiiitivi' tilirils to (Icnov iinisclcs from A', n. p. ; l>. Motor
tiliriis from .V. ii. I. to ticxor.-i ; //. molor tiliril.s from A', it. in. to f.xtcnsor.i ; c,
motor liliril from .V. n. m. to llcxois; c . motor liliril from V. (/. /. tocxttii
sors: it '111(1 ('i, tilirils throwing aiitciiiia muscles mider iiuliieiiee ol' A'. ^;
i\ liliril eoiiiierliiiK A'. ((. /. with .V. n. p. ; /. tihril throwing <'cll hody under
ililluelice of neuropil ; ;;, motor tilirils extending from eell hody to muscles.
removes all the t^'antjlion cells from the neuro))ils of the second
antenna of Careinus and separates them from the whole of the
rest of the nervons system by a circular cut and section of the
* Bcthe, A. Das (Tentrainervpiisystciii von Careinus Maeiias. Ein anato-
inisch-physiologischer \'ersiio)i. II. Tiieil (3. Mitthcilung). Aroh. 1'. iiiikr.
Anat., Bonn, Hd. li. S. :583-453,
i\:7
TIIK XKI'HONK AS TIIK I'MT.
27:^
O'snplia^^cul rniiimissiirc, so tlmttln' iicrvc of the second iilltciiMU
is coiiiu'ctcH with ciul stalioiis (n(>uro)iiluni iiiitiMititii'ii II incdi-
uli', latiTiilc ct postcriiis) ciitirt'ly ili'privi'd of <ran;,'lion-ci'll coii-
lU'ctioii, this sccoMil antciiiiii still retains its tonus and its retlex
exeital»ili(y. 'I'his provt's that the reflex arch does not (or at
least //'W not) iiieliide the cell bodies of the neuroiios. Since
primitive fibrils (Apathy) can be followed directly from the
neuropils into the motor axones without j^'oin;,' throujrii j^'anjjlion
cells, Hethe believes that the reflex path ptes by way of the
centripetal (receptive libres) to the neuropil and thence directly
(without passu,, through the perikaryon of the nn)tor neurone)
into the centrif '; -d motor til)res. Thus, on the whole, Methe'n
studies alTord a strong' and most important conlirmation of the
views of Apathy, the main dilTerence between the conceptions
of the two observers lyinj,' in the fact that whereas A])iUhy be-
lieves that the ElvuivtitKrijUlvr (neuropil of His, Punktsubstanz
of Leydijr) is " diffuse, " Hethe is coniident that this is not so.
That the conceptions concerninff simple contact-relation be-
tween the processes of the neurones previously held must ae-
cordiufrly be modified there can be no doubt, thou<,di that the
doctrine of the morpbolojfical and ])hysiolot,Mcal independence
of the neurones is invalidated but few will be willin<( to ijrant.
Hethe himself retains the term neurone as a desi^Miation for
all the parts easily demonstrable us standing in conne(!tion with
oi\e ffan<flion-celI body.
'1\) c])itomize our aciual kn()wled}i;e then of the direction of
the conduction of impulses in neurones, it may be said that
axopetal conduction has been proved for the dendrites of numy
neurones, and that cellulifuj^'al conduction can he asserted for
the majority of axones, although cellulipetal conduction cer-
tainly occurs in some. Here our certain knowledge stops, yet
the evidence for cellulifugal conduction in many dendrites is
very strong, and it is not lacking for cellulipetal conduction in
the side fibrils. Nevertheless, it would seem very unwise at
present to state positively that nerve impulses nuiy not nass in
both directio7is in all neurones. There is certainly no a)))iarent
reason why they should not ; indeed, just as we have peristalsis
and antiperistalsis in tubes covered hy smooth muscle, and just
as electrical currents may pass in both directions along a piece
of copper wire, it would not be at all im])robable in such emi-
nently irritable structures as the nerve cells that the stimula-
19
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274
TIIK XKliVOlS SVSTHM.
^
tion of citlicr pole or of tlic tcniiiiials of any one of its prooessog
may li'iid to alterations in the energy conditions of the whole
neurone.
That at present we an' well acquainted with the evidence
for the passage of impulses in the neurones in one direc^tion
only does not exclude the possihility that we may at some latt'r
time become cojrnizant of facts which may demonstrate the
conduction of impulses ^A some sort in the opposite direction ;
especially as ])hysiol()gieal experiment has shown that imjiulses
artificially excited in nerve fibres travel in both directions from
the point of stimulation. Though the researches of (iotch and
Horsley * make it appear that on ariilicial stimulation of a motor
nerve, while impulses may pass into the cell bodies of the neu-
rones to which these fibres belong, there is no evidence that
they pass out of the neurones immediately affected into those
related to them anatomically. Hut tiie (juestion of cellulipetal
and (H'llulifugal conduction must be solved first for single neu-
rones before the transference of im[)ulsc8 from neurone to neu-
rone can be settled, and the evidence as yet will not permit us
to deny the passage of impulses in both directions. The changes
in the cell body in the neighborhood of tiie axone hillock oc-
curring after section of the corresponding axone may not be
dependent entirely upon alteration in the character of cellulif-
ngal processes in the cell, but nuiy be influenced in part pos-
sibly by celluliix'tal influences coming from the ])oiiit of section.
In attempting to explain the phenojueiia of tetanus, a similar
possibility should be borne in miiul. The im})ulses passijig iu
one direction could be of an entirely different nature or (juality
from those passing in the other. The whole (juestion must be
for the ])resent left ojjcn. The danger of the ancient mode of
induction described by Hacon as "inductio per enumerationem
simplicem, ubi non reperitur iustantia contradicttiria," is one
against wliich the scientist must ev^/ b'? on his guard.
♦Gotcli, F., nnd V. llorsley. (»n the Maii'.imliun Nervous Sysloin, its
Functions, and thoir Ijoculizalior (Iclorniincd liy an Kleelrical Mitliod.
I'l.il. Tr.. IW»1, liond. {18!)2). vol. clxxxii (!?.). jip. SGT-.VJG.
i!
niAPTKR xx\y.
tllk hklations of tkoimiic to nkuvol's frnctions i\ the
nkiuom;.
Tlic rt'latiotis of trophic clmiif^iis to ncrvtms functions — Inlluciicc of rf|Mise
and activity ii|ioii till' neurones — Studies of llodfje upon the histoiojjy
of fatifjue — Studies of Vas. Mann, ljUf,'aro, and otiiers — Investigation of
hibernal ing animals — Method of indirect eleetrieul stinndation of
neurones.
We may now perlmps most suitably turn to a brief (Mjusid-
oration of tlie niutuiil rebitions tind iutenlcpcndi'iioi' of tbe
tropbic functions and tbose wbicb bave to do vvitb tbo numi-
fcstations of irritability. In tbis connection tbe intlucnce of
tbe repose and of tbe jictivity of tbe neurones upon tbeir
nutrition is of especial importance. Intimately associated witb
tbis topic of repose and activity is tbe question of pliysiolojii-
cal rbytbms so ably dealt witb by Donaldson.* Into a discus-
sion of tbe subject from tbis standpoint it is iu)t my purpose
to enter, a)ul my renuirks will be confined to certaiti more
striking? bistoloffical relations. As has been said above, n priori
there is in tbe neurones, as in everytbin<j that lives, no such
tbinjif as absolute re])ose, since at no tinu> duriiiji life is com-
plete cessation of activity ])ossible. Repose iiiul activity are
here, therefore, merely relative terms, tind are used tbroufjfbout
in tbis restricted sense.
Tbe pioneer in tbe investigation of tbe bistolojjfy of fatigue
is undoubtedly tbe American investigator Ilodge.f
* Op. nt., p. 2!);{.
f Ilodge, ('. F. Some KfTccts of Stimulating (ianglion Cells. .\m. J.
i'sychol.. Malt., vol. i (1887-88). pp. 470-480 ; Some KlTects of Klcctrically
Stiuii.laling (ianglion Cells. Am. .1. I'sychol.. Halt., vol. ii (1888-'8i)), pp.
!{7()-402; The Process of Keeovery from the Fatigue occasioned by the Hlee-
trical Stimulation of Cells of the .Spinal (ianglia. Am. .1. Psychol., Worct^s-
ter, vol, iii (18iK)), pp. ,')i}(t-r)4l5 ; A Microscopical Study of Changes due to
Funitional Activity in Nerve Cells. .1. Morphol., Host., vol. vii (18!)3-'!);5),
275
r
ni
'■\n
^4
1
m
I, -f
^m
270
TIIH NKIlVors SYSTKM.
Ill a .series of l)rilliiint oxperiintiutiil rosoanihos ho has es-
tal)lislie(l the oxistonco of definite! niorplioloj^icial alterations in
the cell bodies of Tienroiies a<'('oin[)aiiyiii<r the excessive* ex-
er<'ise of their |)liysioh)gical fntiction. II(( found that pro-
ionj^ed farad ie stiniu'atiou of a peri|)heral sensory nerve in
the cat led to distinct alterations in the cells of the (*orre-
s])ondiiif,' spinal f^anj^lion (K"ufs. H>'.i, l(!4),and later he was ahle
to demonstrate similar chan^'es in the nerve cells of animals
after a lonj? day's exeniise (English sparrows, swallows, pigeons
[Figs. 1(!5, I(»(5j, and honey-bees). On comparison of the non-
'Wm ^'
». -■■a' "^^K-
w; . Tx. r: ■-■■ ■■■^
Vm. Ki;?. .Section tlirniiKli ^anKlion on doi'sjil root of lirst tlioriicif ncrvct of ait.
Osniic at'id. lliistiniiilatt'd. i Al'trr llod};*'. i
fatigued cells (in case of faradic stimulation, the cells of the
spinal ganglia on the side not stimulated ; in the other in-
stances, the cells of animals captured in the morning) with
pp. !)5-168; Die Nervenzelle bei der (}cburt uiid bcim Todc an Altcr-
scliwilche. .\ii)it. Anz...Tena, Bd. ix (1H!)4), S. 700-710; Chimp^s in ()anf,'Ii<)ii
Cells from ISirtli to Scnilo Death; Observations on Man and Iloney-Mee.
.1. riiysiol., ("ainbridf^e. vol. xvii (1K!)4), pp. 12!»-l;{4; A iMi<To.s(!upieal .Study
of tho Ncrvo Cell during Kleetrical .Stinmlation. .1. Morpliol., Most., vol. ix
(1894), pp. 449-46;{.
TIIK NKUHONK AS TIIK UNIT.
277
th()sc iirtilicially or tiornially fatif^Micd, llodj^c fomid alterations
in the latter hotii in the protoplasm and in tiic niiclens. The
p„, Kv^ —Section tliroii-;!! KiiiiKlion mi dnfsiil mul of lirst llidracic nerve nf cut
iirt<T intermilleii( eleetrieal sliiniiliilidli diiiinf; (ivi' licmrs. Osniic iicid.
(Al'ter IIimIuc. I 'I'lie nuclei iirc diirlser, sliruniuii iind ii ret.'iil;ii- in (iiilline.
ii.id llie priitopliisni is soniewliiit VMcniilated.
nuclei of the tired (U'lls were diminished in size; thev pre-
sented zi<j;zaji horders and stained more intensely than did nor-
mal luiclei ; the protoplasm was often shrnnken, and stained
more foehly than in the cells not fati<rned. The alterations dis-
appeared within about twenty-five hours after cessation of the
electrical stimulation,* whiidi had lasted five hours, and in the
ease of the working animals after a niirht's rest.
(k'rtain of his experiments in whit'h he stimulated livinjr
sympathetic cells where they could be watched directly through
the microscope and compared in appearance with others not
* The olijecfion lias bccTi (luile properly raised l)y van (Jpluirhteii (itifl by
(idldsc.'lieiiler and Klatau that the results ohtainetl from ele(>l ri<al stiniula-
tion can scarcely lie looked upon as e(|uivalent to those dependent upon
nornud fatifjiie. Electricity can not of course be regarded as an " aiUMpiate "
stimulus.
IN
r
i'
m
■1": f
ni
n
i
ih;;iti =
Xift. 'i
■ilH
zi
THK NKKVOUS SYSTEM.
stiimilated, iirc most convincing. Drawings at intervals show
very clearly the gradual alterations which occur.
4'i
'%
^
i),
Fl(t. Kia.
Fi(i. H)ti.
Fl(i. It)."). — ('Miiicni-lticidit drawiii}; nf occipital cuvtcx nl' pi-jcon killed at 5.30 a.m..
to .show rested nerve cells, ('oiro.sive slililiinate for four hours ; ( iaille's stain-
ing. I After Iloilfje. i
Viv,. Kit). -Cainera-liicida drawing of cortex of pigeon killed at 7.15(1 I'.M., to show
changes in cells indicatinn normal daily fatifjnc. (After IIocIkc '
Experiments tilong sinnltir lines have been made by \'as
(Fig. lOr),* Liimbert,f Mann (Fig. l(;s)4 recently l)y Lugaro,»
Pugnat, II and by Evc^ Mann and Vas, while essentially con-
* Vas, F. Sttiilien iibor ilon Ban des Chromatins in dcr syniputhischeii
Ganglienzolle. Arch. f. niikr. Anat.. Bonn, 15(1. xl (lHi)2), S. 875-;589.
+ [janibert, M. Note siir les modifications produites par i'excitation clec-
tricjue dans les cellules nerveuses des gaufjlions s\'mpathi({UOs. ("ompt, rend.
Soc. dc biol.. I'ar., !». s., t. v (18!)3), pp. HrO-SHl.
X Mann, (}. Ilistolofjical Cininges induced in Syni[)atlietic, ^lotor and
Sen.sory Xorve Cells by Fiinetiomil Activity. J. Ainit. and Physiol.. Lond.,
vol. xxix (1895), p. 100.
* Lugaro, E. Sur les modifications des cellules nerveuses dans les divers
etats fonctionncls. Arch. ital. de biol.. Turin, t. xxiv (18'J.")-'!)0), pp. 258-
281 ; also Sperimentale. Se/. biol.. Firenze, An. xlix (1895), pp. 1,')9-19;}.
I Puf^nat, C. A. Sur les modifications hi.stologiques des cellules nerveuses
dans lY'tat de fatigue. Compt. rend. .Vcad. d. sc, I'ar.. t. exxx (1897), pp.
7:J6-7;?8.
^ Eve, F, C. Sym])atlietic Nerve Cells and their Hasophile ('onslituent
in Prolonged Activity and Repose. .1. Physiol., Cambridge, vol. xx (1896),
pp. 3a4-35;{.
Ill
.
ii
^Bi^B
■"
Hi^B
w^
THE NKUllONK AS TlIK I'NIT
279
firming the researclu's of Hodge, have described an enhirgenient
of l)oth cell body and nuclens after brief stiniuhition ; other
authors (Swierczowsky and Tonisa) liavc noticed active niov*'-
nu'iitsof tlie nucleoli during excitation, and Magini has describeti
a displacement of these structures in a direction toward the
axone hillock. Lugaro, who thinks tiiat ijisuttii'ient attention
has been paid to the distinction between signs of cellular activity
and those of fatigue, has made an exhaustive series of experi-
ments fron» which he concludes that the activity of nerve cells
is accompanied by a state of turgescence in the protoplasm of
the cell body ; fatigue, on tlu^ other hand, producing progressive
diminution in the size of the cell bo<ly. lie finds that with
moderate degrees of activity, which correspond to swelling of
the cell body, the nucleus undergoes no alterations in size ; but
if the activity is })rolonged to fatigue it slowly becomes snndler.
The stainable substance of Xissl, TjUgaro believes, undergoes a
slow increase in amount in the earlier j)huses of activity, while
later, when the cvW becomes fatigued, it is diminished and is
more diffusely distributed throughout the cell body.
;.■— ti
ii'»
:m n
Fl(i. Hi". --Sections tliviiUfrli tlic superior cervical friiiiKlioii of tlie raliliit staiiieil
l)y Nissi's iiietliod. i After Vas. i ^ l.OOO diameters, ii, section tlirou<;li nor-
mal Kaiifilioii : ''. section tliroufili frmiKlion after stimulation of symiiatlietic
trunk for lift<'i ii minutes with faradic current.
Eve could find as the only change resulting from protracted
activity the occurrence of a slight dilTuse blue stain in the cell
substiince (Nissi's method). His i<U>a that this is due to forma-
tion of acid by the cell with consc(|uent slight solution and
difl'usiou of the material which stains blue will, considering
I
1
11*!
#r
35fSVi?»^^™.
f
!>
i!r
i i :
2S0
TIIK NKK VOL'S SYSTEM.
t;|j
-Hi|l|
what is now ktiowii of the N'issI bodies, (ioiibtloss niot't with
opposition.
Studies ol" tiie nervous system of liibeniiiting uniniuls have
beei 'indortaken by Jacobsoiin.* He found, however, no dis-
cer Iteration in the motor cells of the ventral horns.
'v- i
mil
Fid, UiH. — Two motor cells from luinlmr i('};i<iii ol' spinal con! of don fixed in
siil>limate and slaiiiecl in tiduidin blue. <i. from the fresh do;; : 1. pale nii-
eh'us ; 2. dark NissI spindles; 3, hnndlescd'nerve (ihrils. /;. fmiii the fatiKiii'd
do^ : 4, dark shriveled nucleus; 5. pale spindles. (After Mann.)
The influence of prolonged illumination upon the retina
has been studied by IVrgens.f
A very ingenious suggestion in order to do away with direct
traumatic influence or direct })hysical or chemical influence by
an electric current upon the neurone has been made by (Jold-
scheider and Flatau.;]; They suggest that one stimulate the
* Jacol)sohii. Ij. Feber ilas Atissehen dor inotorisclipii Zelleii iin Vonlcr-
horii lies liiickenmiirks naeli Hulic uiid lliuij|;er. Neurol. C'eiitralbl.. Leipz.,
lid. xvi(18!)7), S. 946-948.
•f I'ergeiis. K. Action dc la luiiiiere siir la n't inc. Ann. soe. roy. d. se.
nu'd. et iiat.de IJrux., t. v (18iK>), pp. 389-421.
J Goldseheider, A., iind K. Platan. Norniale uiid pathologischc Ana-
tomic der Nervcnzellen auf Gruud der nouoren Forschungen. Berlin (1898),
S. 35.
-. — ^^
w
TIIK NKLUONK AS TllH UNIT.
2sl
motor ri'ffion of the (UTchral cortex and tlicii cxaniim' the ci'll
bodies of tlu^ (rorrcspondiiifj lower motor iieurom-s (ventral lioni
cells). In the same way the lower motor neurones could he in-
directly stimulated hy way of the peripheral sensory neurones
(spinal ^an^dion colls, dorsal roots of spinal nerves), after which
the morj)hol()^ical appearances of the ventral horn cells could
be compare<l with the normal. In such an event, as they em-
phasize, it would he important not to confine one's self to the
use of Nissl's method, which gives definite results only with re-
gard to the tigroid masses, but in addition other methods, like
those of Flemming, Held, and M. Ileidenhain, which demon-
strate! morci parti(!ulurly the strne^ture of the ground substance,
should be employed.
While it is evident that additional research is still urgently
called for, it will be seen that enough lias already been done to
supply us with some direct microscopic evidence for the inti-
mate relations existing ])etween the state of nutrition of the
cell and the manifestation of functional activity. In substan-
tiation of these results there exists a considerable amount of
pathological and pharnuuH)logicaI evidence, some examples of-
which will be considered in the following chapter.
i.
i ' I
ill! I
1 ■*
ill
!l
! 1
!i!!
ml
i'^
I J
CHAPTER XXV.
ox THK IIISTOLOdlCAL A I.TKKATIOXS IX XKl'HOXKS DTK TO
TlIK ACTION OF I'OISOXS, AM) A COMPARISON OK TIIKSK
WITH THK KKKKCTS OK TKA CM ATISM.
Clian<;es in the iieiiroiie.s in iiit'ixicatJDiis and infections — Comparison of
primary lesions in llic cell Ijodius of nenronos with tliose secondary to
lesions of axones — Thuorios coneeruing trophicity.
\\'\: !iro ill ])osses8ion now of a largo .series of studios by
Xissl's and other methods whieh have been uiidortakon to in-
vestigate the offeets of poisonous substances u|)oii tlie neurones.
It wouUl be impossible to even refer to all of these, l)Ut a few
at letist may be mentioned.
' ' Xissl* has demonstrated definite lesions in the large motor
cells of the ventrtd horns of the rabbit after poisoning with
strychnine, veratrin, alcohol, ])liosphorus, the toxines of tetanus,
and triojial. He has also shown the alterations produced
in the Pnrkinje cells and spinal ganglion cells of the rabbit
after lead poi.soning, and the chiinges in the cortical cells
after poisoning with alcohol, morphine, and lead. Nissl has
empliasized the tlittVrences of the tdterations produced in the
same group of cells by the action of ditferent poisons, and has
further demonstrated that the same poison can lead to entirely
different results in different types of cells in the same animal.
He has referred not only to the changes in the (diromatic and
achromatit' substance, but also to the nuclear alterations in
such intoxications.
Xis.sl has investigated the nerve cells in acute, subacute, and
chronic forms of poisoning, since he finds that the ett'ects of
poisoning viiry very much according to the time during which
the intoxication has been active. Especially interesting are the
* Xissl, F. Ueber die Veraiuleninfjen der Xervenzelleii nach experimen-
tell crzeuster Vorfjiftniif^. Neurol. Centralbl., Loipz., Bd. xv (IHUG), S. !);
Allg. Ztschr. f. Psychiat., etc., Berl.. Hd. liv (18!»7), S. 1-107.
282
TIIK n'kuhonf: as tiik rxiT.
2S.'i
results which he has obtaimul in his so-nilled "siihaciito maxi-
mal intoxications," in which the aniniul under experiment re-
ceives daily an ainoimt of |»oison just short of the lethal dose
until death occurs (after fron. a few days to several months).
The alterations in arsenical poisoninji; are well showji in Fij;.
100. Th • whole nerve cell is swollen, there is nuirked diminu-
Fid. Ulit. KtVccls of iiisciiic iiiioii the nerve eell. i After V. Nissl. Allj,'. /Isclir.
f. ISychiiil., etc., I'.erl.. lid. liv., 1M!»7. i The cell ti. the hit of the I'lKUre is
iiciniiiil : Ihiit to the ri^'iit IVdiii iiii iiiiinia! poisuneil liy Mrsenic.
tion in the amount of tigroid substance, so that it is often im-
possible to distinguish the chronmtic from the non-chromatic
portion of the cell. Alterations in the nucleus can also be
made out.
In his stiulies of phosphorus poisoning Nissl found very pro-
fouiul alterations in the nerve cell — alterations which teiul at
the beginning to atTect often one })ortion of the cell in prefer-
ence to others, although no definite rule as to the exact portion
likely t<» be affected in a given instance could be laid down.
In advanced stages of the poisoning the cell is remarkably di-
minished in size and the nucleus smaller than nornuil. The
architecture of the cell becomes completely obscured, the only
trace of tigroid remaining being a few dustlike particles and
irregular granular nuisses. The cells may even go on to com-
plete atrophy, and eventually entirely disappear (Fig. 170).
The effects of veratrin poisoning are somewhat different.
Hero and there in tbe cell body of the neurone, tigroid masses
•lisappear, leaving small cavities in the ground substance.
ni
i •"..
\
fj
/(
i!;
2.S4
TIIK NKI{ vol's SVSTHM.
WlicrciiH cortiiiii <>l' the li^froitl masscH imdcrf^'o this clmn^c,
(ttliciv rt'niiiin iipiKirciitly entirely unalTected, (ir are at nutst lint
sli^'litly altered. In prolonj^ed poisoning' tlie j,M'onnd siihslaiieo
A,
i*"^**
'.^'
'^^.
A
■■mu
(I
If
Fi(i. 170. — Thccd'cflsdl pliosplioriis poisoiiiiiK upon tlu- iifiirimt's. ( .Vftcr V. Nis.sl,
AIIk. /Isclir. r. I'syi'liiiil.. etc., I5crl.. I?«l. iiv, lHi)7. i The icll in tlic upper
ri^lil-liaiiil conu'r is nnniiiil ; mII tlic other cells sin iw the elleetsdl' phosphcirus
poisiiniiiK.
may lie involved, and the nuclons of the cell diminishes in size.
Miiny of the cells ])re,'^cjit a ditfnse stiiininff, the limits of the
NissI liodies heiiifj; hut very indistinctly visihle (Fijf. ITl).
For Nissl's tindin<fs in poisoning liy silver, strychnine, mor-
phine, tetanus, lead, and alcohol, the orifxiiiiil jiiihlications of
that author may be consulted.
Inasmuch as different poisons act upon the same variety of
cell in a dilferent Wiiy, iind as tlu^ siime poison ctin influence
different types of cells in different ways, Xi.ssl believes that we
are thus afforded a new and important metins of analyzing,' the
functional activities of the different "ifroups of cells inside the
central nervous system. Hy administerinjf elective ])oisons iind
comparing the clinictd aiul jisycholoj^ncal manifestiitions dui'in<j:
life with the alterations in the cells after death, it nniy he pos-
sible to estid)lish the function of the individuid cell varieties
and alontr with these the function of the various localities in
which they tire situtited.
TI!K N'KI'RONK AS TIIK IN!T.
2S5
Tlu'sc views of Nissl un* supported in the iiiiiiii hy liii^tiro,
who lias studied the altenilictiis in the nerve cells after lead
and arsenie poisonin;;.* It is Lu^^'aro's idea that the ehroniatie
j)orti(>n of the cell (Kij;. IT".') is the tirst to he alTeeted hy
poisons, and that the alterations of the aehroniatie sui)slanee
follow with a rapidity which depends upon the kind of poison
and the ty]»e of (!ell coneerned. Alterations (»f the (diroinatic;
part are reparahle, hut he doubts if this ht; true foi' the adiro-
nuitic i)ortion. The alterations in the |)i'riphery of the cell
come on earliest ; ehanj^es in the nucleus occur last, when the
resistance of the cell has been exhausteil. ("han<i;es in the den-
drites he thinks succeed those in the cell body, a point of view
in o[)position to the position taken hy Monti and Berkley. 'I'he
chanjfes in the s{)inal {.(an^lioii cells in arsenic intoxications,
described by Lu^aro, are pictured i)i Fij,'. \'72.
/i
Fkj. 171. Tlif ftU'cts of vciiitrin iMiisouiiiic uiHiii the iifuniin's. i .VfttT !•'. Nissl,
.Mlj.'. Ztsclir. C I'syciiiiit., itc, I5i'rl., lid. liv, ISit". i The cell in tlic lower
rinlit-liaml roriicr is iiorniiil ; the otiici-s sliow tluM-tU'cl of vcr;ilriii poisiiiiiiiK.
The effect of strychnine upon the lower motor neurones lias
been studied by Nissl, by (ioldscheider and Klatau, and others.
The chanf:fes are closely allied to those which are found in
* Lupiro, K. SiiUo iiltfrazioni dcgli t'lt'inenti norvosi iiogH iivvolfim
mcnti per arsenco e per piombo. lliv. di patol. nerv., Firenzo (1897), vol.
ii, pp. 49-64.
11
280
TIIK NKIIVOUS SYSTKM.
4
lilliir'
tctiiiuiH poiHouinj;. They niiiy develop very «|in('l<ly iifter tlio
injection (>r the ulkiih>i(l, even as early as three iiiiiintes after
suheiitaiieoiis injection. Alterations in the nucle(»li precede
tiiose in iiio tigroid nuisses, uceording to (loldscheider and
g^pS"
pfeii
V
^
^'^Hljb^ ■v^r'^;^ |;^^,i A^r ,v: ^^A,^
■^^khy^l^'
..>»■'
Fid. 172. -Two s|(iiiiil Kii'ifjliiiii cells sliowing poriplicnil fliroiiiiitolysis in arscn-
iciil poisdiiiii},'. (.\t'l<'r K. LiiKuro, Kiv. ili piitol. lurv., Fiicii/.i'. vol. ii, lsit7,
>'. r>:< KiKs. ~ and :{. I Siihliniatc fi.xation ; hii-iimto.xylin .staining.
Flatau. No distinct proportion conld be established between
the morphological alteration and the amount of functional dis-
turbance. Functional disturbances were recovered from some
time before the iiistological a])peiirances hud again become
normal.
This absence of any strict proportionality between the vis-
ible morphological changes and the degree of functional dis-
turbance is of the highest importaiu'e, and such incongruity
should hold in check those zealous investigators who, without
adequate data, are ready to inter])ret every histological finding
in terms of the clinical symptomatology. As a matter of fact,
m
uU,
TIIK NKUUONK AS TIIK IN IT.
287
the altcnitioiiH in llic tcIIh in iiciitc iiiid clironic poiHonin^', so
fur iiH tlicy have hi'cjj Htudicd up to the prcHctit tijnc, can
Hcar;'('ly l>t' l>roiif,'lit into relation willi the dinw-al syrnptonirt.
The occiirrcnct' of Nissl's "acute cell disease " (c/V/f ////'/v^) in
a whoh' series of entirely difTereut disease-jjictures is further
evidence of our lack of infornuition with re^'ard to the corre-
spondence of the th'tnoiistralih' histolo^'ical alterations in the
neurones and the sytnptctnis met with during' life. That the
histological alterations have functional e(|uivalents, however,
no one eun douht, and other investigators have gone too far in
dcnyinj^ the e.xistence of any relation hetween the tu-rve-t'ell
chanties demonstrahle in poisoninj,' and the nervous disturh-
ances met with durinj,' life. .Ml that we can say at jiresent is
that the appearance and disappearance of the nuijority of the
clinical symptoms are independent of the relatively gross intra-
neuromil struct ural alterations thus far descrihed. Tlu' corre-
spondence in all prohahility lies in the liner structural altera-
tions indiscoverahle hy our present methods (»f examination,
and will first be ascertainahle when advances in technique per-
mit of the application of procedures which reveal such finer
changes.
Very important from a therapeutic standpoint are the in-
vestigations of Hrauer.* Thi,>-' investigator studied the cell
bodies of the 'Huronos in the central nervous system of some
twenty-three rabbits poisoned by mei'oury. Some of the animals
wer(^ subjected to acuci', others to subacute, still others to
chronic poisoning with this metal. The poison was given by
the mouth, subcutaneously and intravenously. In addition to
the marked altenitions in the kidiu'ys aiul intestines distinct
paralytic phenomena on the part of the nervous system soon
became manifest. The paralysis gradually increased as the
poisoning continued, the relle.xes were exaggerated, aiul the
aninuds exhibited an outspoken ataxia. Sec^tions of the nerv-
ous system studied with Xissl's method showed large numbers
of altered cells in the ventral horns. Among the altered cells
there remained a considerable number which did not appear to
be affected, although tlie relative proportions varied much in
different aninuils. Very frecjuently Hrauer met with localized
* Hrauer, L. I>er Einfliiss dcs Qucoksilhors auf das Nervensystoin des
Kaninchons. Deutsche Ztschr. f. Nervenli., Lcipz., Bd. xii (1H97), S. 1-67.
;ii It
/I
II
1. ■
Ij
ll|.'L
m
iiiiiij
288
TllK NKHVOUS SVSTKM.
li ;•
m
aroas in individual colls in wliicli tif^roid bodies wcro boj^inning
to break up. TIk! line particles l)ecaine scattered through the
{fround substances, and the cell
contents often presented a dust-
like appearance. The bearinj^
of suidi observations ujjon the
treatment of syphilis is obvious.
It would take too Ion*:; to
consider all the reports of stud-
ies of into.vication even if only
those made recently
were referred to.
Anionjif the recent
researches, those of
Sarbo * on ana>mi(;
alterations, Vas on
nicotine poisoning, Dehio on
strychnine poisoning, Manersi
on strychnine and chloroform
poisoning, Berkley on alcoholic
and ricin intoxications, Masettif
Fi.!. i7:i.-.\n..iv.M-..|iinm>a imrt.f *>" autipyriue intoxication, of
tJK' spinal .Old . I. •priv.di.ii.luo.i lor I>andi t Oil bromine, (M)caine,
six hours tliriilluli liKiitlirc of the ill)- . . . . .
(loiiiiiial aorta. ( AitiT (1. Marines- meotiiic, and antipyriiie poison-
co, l,a I'lfssf iiit'dicalf, I'ar., 1S!)7, p. •,,, i...,i,u(^ .,.,,1 VX'., ....:..,,*,,.. t»
45, n. V.) Tlu' p.iipii..ial poiii.Iii '"K. l^iislett and Warrington •»
oftlifcytopiasiiKoutaiiisoiiiya iVw oil lead poisoiiiiig, Wright 11 on
tigroid masses, altlioiif;li the latter . , ' . • ,, ,
are still iimiu'ioiis near tlie mieleiis. broilU tO poiSOlllllg, Moiirck and
* Sarlio. A. I'cber die KiiekciiniarksveriliKU'riiiij^oii iiach zoitweilif^er
Verschliessmif^dcr liiiiicliuorta ; eiii Meitraj; /iir Piitlioiofjifiles (luiif^lioiizell-
kerne. Neurol, ('i'iitfall)l.. Leip/.. 15.1. xix (iHi»4). S. (iB4-<iTl.
t Masetti, H. IjC altcrazioiii del inidollo spiiiale mdravveK'naiiioiito
croiiicd sperimiMitnle per aiitipiriiia. Hiv. s|)lt. di freiiiat., Kef^gioMiiiilia,
vol, xxi (ISlir)), pp. (i(iS-()77.
X IVuidi, K, I'eber die Veriiiiderungcii dos ('eiitraliiprveiisystems naeli
cliroiiischpr Vergi filing mil Hrotn, Kokain, Nikotiu uiid Antipyrin. Uiif,'ar,
Areh. f. Jh>d.. Wiesb,. Mil. ii (1H!);{-'!M). S. 2r)7-'JH4,
* Ija.dett, K. K., and W. W. Warrington. 'I'lie Jlorbid Anatomy of a
Case of I.o-.i I'aralysis, Condition of the Nerves. Mnscdes. Muscle Spindle.s,
and Spinal Cord. i?rain. Lond., vol. xxi (IHDM), pp, 234-2:51,
II Wright, It. K. The (."erebral Cortical Cell under the Influence of
l*()isonoiis Doses of I'olassii Bromiduin. Brain. Lond., vol, xxi (1898), p[i.
18G-2a3.
TlIK NKTUONK AS TIIK INI'I'.
2S<>
Mess* on llic cITtn'ts of vjirious poisons, should he iiiciitioiKMl.
Till' t'tl'i'ft of (MittiM<i; oil" the blood supply to tlio lu'uroiics is
illustrated in l-'ii,'. 11:5.
TluTi' exists mIso a series of researelies upon Jieute and
chronic infectious processes, those experimentally produced
anil those occurrin;; in nature. .\inon^f these may he im'n-
tioned ihe studies of Hahes,f Heck,;]: Dejeriiu'," K\vin<,',|| (iold-
seheider and Hraseh,"'' (loldscheider and l"'latau,^ Lu^faro,|
Nieholls,| Sahrazes and ('al)annes,| .Marinesco.**
A he<j;innin,<j: has been made in the study of acute and
chronic degenerative processes in Imnian beinj^s and in ani-
lUids, some of known and some of doubtful ori<,nn : The
researches of .\c(|uisto and rusateri,ff Ballet, JJ Uallet and
* Miiiil'i'k, .1., l>t P. Ui'ss. I,('siolis lines dcs (•('Hull's liiol rices (le Im iiKieiie
(■'|iiiii("'ri' duns les divers ('■litis d eiiiiKiisoinieiiu'iil. Uev. iieiii'ol., I'lir., I. \.
(l.sitT). N(i. ',»:{.
+ liiilu's, \'. I'elier den ImiiIIuss der verseliiedeiien inrecl ionen .■mf di(^
Nerveiizellcn des Kiiclvcinnarks. iJeri. kiiii. Wclinselir., 15(1. ww (IS'.IS),
S. C ; ;i() : oil.
\ Heck. .\. i>ie N'eriinderuntceii der Nerveiizellcn lieini ex|ieriinentellen
Tetanus, drvosl iielil.. IJiidiiiiesI, vol. xxxvii (1K!);>), No. '.V2. iiel'. ini .Neurol.
(Vntrallil., \a'\\,/... ISd. xiii (IS',14). No. ^M.
* Dejerine, .1. Sur la eln'oiualoiyse de la ecllule nel'veuse au eoiirs des
iiifeclious avec liyiierllieruiic. ('oni|it. rend. Soc. dc liiol., I'ar., 10. s., I. iv
(18!)7). p. 12H.
II Kwinj;. .1. Studies on (iiiiifjlion Cells; a I'reliniinury Comnnniieaiion.
Med. ifee.. N. Y., vol. liii (ISitS). pp. rtV\ ,->!7.
'■' Cidldselifiiler, A., und I'". Mruscli. I'elier die N'eriinderunp; inenseliliclier
Nerven/.ellen boini Kiober. Fortselir. d. Med.. Herl.. Md. xvi (1H!»H). S. 12(M'.>S.
{) (ioldselieider, .\., and I'l. I'Malau. Norniale und pulliolo;;isclie Aiuiloniie
der Nerveuzellen auf (irund der neueren l''or.sfhiuit;i'ii. 15(M'lin (18!W).
J liUpiro, I'l. .Mti'mzioiii dellc cellule iutvosr iiella peste bubbonica
sperinientale. Uiv. di patol. nerv., I''irenze, vol. ii (1H!(T), pp. '.'11-'.] M.
JNielioll.s,,!. Sludiesol'Tyithoid Kever. .1. Mxper. .Med., N.Y., vol. iv (IH!)!)).
{ Sabrazes, .1.. el ('. ('abuinios. Noti> sur los lesions dos lu'llules iiervoiise.s
de la inoelle dans la I'aj^e Innnaint'. N. ieono;,^ de la Salp(*tri("'i'e. Par.. I. x
(1S',»7), pp. l."i.">-t(M.
*♦ Marinesi'o, (i. Sur les l(''si()ns dii svsleme nerveux central an eours
des maladies inl'ectieuses. Coniiit. rend. Soc. de biol.. I'ar., 10. s.. I. iv (18!>7),
pp. 7!»r)-7'J8.
ff Ai'ijutsto. \'., ed. I'l. Pusateri. SuH' aiuitoiiiiii |>iitol()}j;iii dejili eleiiuMiti
nervosi lu'ir uremia aeiila speriincntiile. Hiv. di jmtol. nerv.. I''irenze, vol.
i (iMSHi), pp. ;{77-;!.sr).
XX Hallet, (i. I,es l(''sions e(''r(''brales de la piiralysio jjein'Tiilo etutliees juir
la metliode di- Nissl. Ami. nied.-psvcliol.. Par., H. .s., t. vii (IH'JS), pp. 44H-4.'jO.
30
I.
I
■|..S?
m
m
I 1 '.
\
h
V
mm
lm[iiP
290
THE NERVOUS SYSTEM.
Dutil,* Boedoker and Juliusbnrger,t Cramer,J Dojerine and
Thomas,* Frie(lmann,|| Alarinesco,^ Monti,^ I'opolf,! II<)(!li4
Qaervain,J Sacerdotti and Ottolonglii,** Schatt'er,f f Lugaro
and Cliiuzzi,JJ Soukhanofl,*** and 8troobe.||||
* Udllet et Dutil. Sur quelqucs lesions <^xpi'riinentalcs do la cellule
norveuse. Xllth Internat. nicdic. ("ongr. zu Jloskau, Neurolog. Centralbl.,
Lcipz.. Bd. xvi (1897). S. 015-91(5.
f Boedekor and Juliusbuiger. Auatomischc Bofunde bei Dementia para-
lytica. Neurol. Centralbl., Leipz., Bd. xvi (1897), S. 774-779.
X ( 'ranier. A. Pat iiologisch-anatoniischer Befund in einom acutcn Fallc dor
Paranoiagruppo. Aroli. f. Psyeliiat. u. Xorvenkr., Berl., Bd. xxix (1896), S. 1-24.
* Dojerine et Thoma.s. Sur I'absence d'alterations des cellules ner-
veuses do la moelle ('j)iniore dans un cas do paralysie alcoolique. Conipt.
roiid. Soc. de biol., Par., 10 s. (1897).
II Fricdmann, M. Uober progressive Vertinderungcn der Ganglienzcllon
boi Hntziindungen, nobst eincin Anliang iiber active Verilndorungen dor
Axoncylinder. Arch. f. Psychiat., etc.. Berl., Bd. xix (1887), S. 344-268.
^ Marinosco, Pathologio de la cellule nerveuse. Rapport presento au
Cdiigros international de medocine a Moscou. Paris (1897).
^ ;Mouti, A. Sur I'anatoinie patliologique des olonients nervoux dans les
processus provenant d'emboli, me cerebral ; considerations sur la significa-
tion pliysiologique des prolongemonts protoplasmatiquos des cellules nor-
veusos. Arcli. ital. de biol., Turin, t. xxiv (1895-"96), pp. 20-;5;3.
I Popow, X. Arch. f. path. Anat., etc., Berl., Bd. xciii (1883), S. 351-3C6.
I Ilooh, A. On Changes in the Xorve Colls of the Cortex in a Case »(
Acute Delirium and a Case of Dolirum Tremens. Am. J. Insan., Bait., vol.
11 V (1S97), pp. 589-606.
I do (^uorvain. P. Uebcr die Voriindorungon des Centralnorvoiisystoms
bei oxperimenteller Kacliexia tliyroopriva dor Thiere. Arch. f. path. Anat.,
etc., Berl., Bd. cxxxiii (1893), S. 481-550.
** Sacerdotti, C., e D. Ottolonglii. Sullo altorazioni dogli olomonti nervosi
nolla (liserasia uremica sporiiuontale. Riv. di patol. nerv., Firenze, vol. ii
(1897), S. 1-8.
ff SchalTor, K. Ueber Nervcnzollveriinderungen wiihrond der Inanition.
Xeurol. Conlralbl., Leipz., Bd. xvi (1897). S. 832-8:57 : also Das Verhalton
der Spinalganglionzollcn bei Tabes auf Grund Nissl's Fiirbung. Xeurol.
Centralbl., Leipz., Bd. xvii (1898). S. 2-7: also Uobor X'ervonzollonvoriindor-
uiigen dos Vordorhorns boi Tai)es. Ein Boitrag zur Pathogenose der tro-
phischon Storungon der Tabes. Monatschr. f. Psyeliiat. u. X^eurol.. Berl.,
Bd. iii (1898). S. 64-98.
11;. Lugaro, E., e L. Chiozzi. Sullo alterazioni dogli olomonti norvosi noU"
inaniziono. Riv. di patol. nerv., Fironzo, vol. ii (1897), pp. 394-400.
** SoukhanolT, S. Sur I'histologio [tathologique do la polyin'vrite dans
SOS rapports avoc los lesions de la cellule nerveuse. N, iconog. do la Salpe-
tricre. Par., t. x (1897), pp. 347-354.
III Stroobc. II. l'(^l)or Voriindorungon dor Spinalganglion bei Tabes dor-
salis. Centralbl. f. allg. I'ath. und path. Amit., Jena, Bd. v (1894), S. 853-855.
THE NEURONE AS THE UNIT.
291
In the investigiition into the changes in the luiman cerebral
cortex no one has thus far had so mucli experience as Franz Nissl.
In a recent paper * he distinguishes seven forms of alterations
in the cells of the human cortex: (1) Acute cell disease; (:*)
chronic cell disease ; (:{) severe cell disease ; (4) combined
disease forms; (o) vanishing of cell; (G) simple rarefaction;
(7) granular breaking up of the cell.f
Xissl lays much emphasis upon the first of these forms, the
rio-called acute cell disease. According to him it runs the same
course in every instance, hav'ng always the same termination,
and when it has once appeared it involves all tlie cells of the
cortex without exception. The changes are so characteristic
that, after once • jing them, one can make a positive diagnosis
without difficulty. The disease does not aifect a part of the
cell only but involves the whole neurone, the staiiud)le as well
as the unstainable substance, the nucleus as well as the cell
body, the axone as well as the dendrites, all parts being involved
apparently in the same degree. In this form of neurone change
the unstainable substances are so altered that they become
stainable, a fact which makes Nissl think that liis " unstain-
able substance " consists not only of a fibrillary constituent,
but, in addition, of one or several other substances.
Xissl finds this acute cell disease not only in acute paralyses
hut in a great variety of psychoses, and also in patients who
have not been the subjects of mental disease in the ordinary
sense, but who, succumbing to various disorders, have before
death been partly delirious, partly somnolent. The involve-
ment of all the cells in the cortex is an exceedingly interesting
feature, and one met with rarely in any other form of disease.
An instructive paper dealing with the alterations discover-
able by Nissl's method in the human cortex is that of August
lIoch,J of the McLean Hospital, Waverly, Mass. Working in
* Xissl. F, Norvcnzt'lli'ii mid jj;riiue Subslanz. Miiiich. iiu'd. Wehnschr.,
l?il. xlv (1H!»8), S. 988; 10:>3: lOGO.
t In this country Iloch (Ilocli. A. On t'hangos in the Nerve fells of the
Corlox in a Casp of Acute Delirium and a Case of ni'liriuni Tremens. Am.
.1. lusan., Halt., vol. liv (181)7), pji. r)8!»-G()G) has described one ease in wliieh
the "acute cell disease" (acute Verdndenmg) and another in which the
"severe cell disease" (nrhwere IV/7'//)(/c/'«;ir/) of Nissl existed. His descrip-
tions of the changes are the fullest and most accurate hi the English language.
\ Uoch. A. Nerve-Cell Changes in Somatic Diseases. A Preliminary
Communication. Am. J. Insaii., Bait., vol. Iv (1898), pp. 2:11-240.
t-
,5'
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7 ,
■ ■! ! '
itit
I ll'
2[)-2
TIIK NHR VOL'S SYSTHM,
.
if!
I mm
III i
Nissl's liibonitory at llt'idellH'i'^, Iloch liud l)eou iin])res.so(l witli
tho fiT(|iu'iicv with wliicli cliaiif^U's wciT t'ouiMl in the cortical
nerve cells in individuals dead of diseases of ditt'erent kinds.
Kecogniziuf^ the iin])ortanee of a tlioroiif:;!] knowledge of the
possible ehanjjes in the eells in somatic disease I'or the inter-
pretation of the patholo<j;ical alterations met witii in tlie brains
of the insane, iloch directed his es])ecial attention toward these.
In the ])api'r mentioned he deals with a particular cell altera-
tion, which he designates "cell shrinkage." lie has studic'
this change in human beings, in whom it occurs in the most
diverse diseases, and also in experimental animals.
This alteration in the cells, as he describes it, is found
chietly in the medium-sized aiul smallest pyramids, as well as in
the cells of the fifth layer. The contour of the neurone is dis-
torted and shrunken, and there may be much retraction of the
borders of the (H'11 l)ody between the processes, so that a })art of
tlic cell body may, at iirst sight, look like part of a cell ])rocess.
A well-marked honeycondj structure is visible in the cell body,
and is sometimes indicated in the processes. The nucleus is
darkly stained, dijuinished in size, and often distorted. In
Nissl pre])arations it looks honmgeneous ; the nucleolus is often
oval in shape, and nniy be paler than m)rmal, but iu>ver shows
a purplish hue. Instead of the honeycomb appearance, the pro-
toplasm may be " crumbly-looking."
While these changes occur in the smaller pyramids and the
cells in the fifth layer and in a few of the larger pyramids, Iloch
finds a very different a})pearance in most of the larger pyramidal
cells and especially in the largest pyramids (not the motor or
Betz cells). There may be but little alteration in the extermd
form of the cell body, but there is nuirked (duinge in the distri-
bution of the stainable substance throughout the cell. The
stainable substance is seen at the base and at the sides of the
pyramid, sometimes forming a rim around the periphery of the
cell ; often this rim is not continuous but consists of a number
of separate " crumbly " portions. The basal processes are much
more altered than tlie large apical dendrite, especially in the
larger cells. The alterations in the nucleus are very character-
istic. No nuclear mend)rane can be demonstrated, and the in-
terior of the nucleus shows no trace of a shar]) design, in Nissl
preparations frequently looking entirely homogeneous. The
nucleolus is, however, unaltered. The change just described
I i
TIIK NELKON'K AS TIIM I'MT.
293
H(»cli (Icsignatcs " altcnitioii with rarefaction around the nu-
cU-iis."
As a rule the larj^o motor cells look entirely normal.
In two of iiis cases Hoch met with an alteration in which the
cells may he compared to vesicles. Around the nucleus he found
a narrow rim of "crumhly-lookiiif,'" substance, then a clear area,
and at the periijhery of the cell body another ac(!umulation of
" cruml)ly-lo()kin<f " suhstajice. There may he a marked accu-
mulation of the staiiuihle sui)stance at the site of orif^in of a
basal i)rocess. The nucleus in such cells varies much in appear-
ance; sojuetimes it may be homogeneous; it may be pale; it
may be indistinctly spotted, or sometimes it may look almost
normal. The feature common to these cells is the vesicular,
l)allooidike appearance of the defective cell body. The cells
e.\liil)iting this alteration were met with only in the ui)per layers
of the cerebral cortex.
It struck Hoch that the vesicles may be due to o'dema, and
lu' accordingly experimented on the cortex of the rabbit. A
piece of a rabbit's brain immediately after decapitation was
placed in distilled water for from twelve to twenty-four hours
and then hardened in alcohol. Another piece was treated with
nornud salt solution and subse((uently hardened in alcohol. The
cortex treated with water showed by Nissl's method typical
" vesicular cells," while the cortex treated with nornud salt so-
lution showed cells which corresj)onded in every detail with the
typical "cell-shrinkage." Kxperiments on the human cortex
obtained from healthy individuals at auto})sy, so far as they went,
contirmed the results obtained in the rabbit. Hoch was not able
to produce experimentally his "alteration with rarefaction
around the nucleus."
Hoch concludes that o'dema is an important factor in the
production of vesicular cells. He points out in his article the
importance, however, of bearing in mind the possible appear-
ance of artefacts due to the action of alcoliol upon the tissues.
It maybe that the modification of Nissl's method recommended
by Lord * will be of service in the exclusion of such artefacts,
* lionl. J. H. A Now Nissl Mctliod : XoniiaK Vll Stnicturc and the Cyto-
l(i{;i('al Changes tcriniriatiiif? in I'^itty Degeneration ; some Reniarlis on Cell
Pliysitilofry and its IJeliitioii to Insanity ; a Note on the I'se of I'icrofonnal
(Jenerally. and in Hevan Lewis's Fresh Method. J. Ment. Se.. bond., vol.
xliv (1898). pp. «l):i-70().
.I
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294
TIIK NKIJVOUS SYSTKM.
siiKM' in liis proctMlnrc, its in that of Hcviin liCwis, fi'()?;t'ii sections
iin> (>in]ilovi'<l iind alcoliol lixatioii is avoi(l*Ml.
There wouhl appear to he some jfrouini I'or helleving that a
Htiidy of tlie chuiiffes in the nerve cells enal)les ns to tlistinfjuish
hetween the microscopic picture of llu^ cell l)o(ly of a nenrone
after a lesion to its axone and that \vhi(di results from the
direct a<'tion of toxic suhstances upon the cell l)otly of the
neurone.
We )io\v know verv well the appearances of the correspond-
ing ventral horn cells of the sj)inal cord and medulla after scc-
Flii. ITI. -("ells from I lie nuclei of (lie ocliloiiioloriils iicvvos of llic i';it tliillciii
<liivs iiflcv snlion of tlii' root lilircs of tlic nerve on one side. (Afler I).
l"liit;iii, Koil-elir. (I. Meil,. Uevl.. Hil. xiv. IS'lti. '\';\(. i. Kijis. :i iinil 4.) <i. eell
from mielens of siili' not oiieniled upon, sliowiiiy; (,V|iie;il t-tielioelivoine !if
funsziMUeiit of NissI liodies: /). eell from nnelens of siile oiieniled upon, 'j'lie
liomoKeneons dnsllike ;ip|)e;in(nee is vepresenled. Here iind Ihi-re sinule
iMV.uer ivreiiular Nissl liodies are visilde. The nucleus is displaced to the side
of the cell.
tion of the axones of a motor nerve (r/VA' siipni). After ji short
time the cell hodies of the ijroup of neurones (>om'ern(>d ai)pear
somewhat swollen and there are marked chancres in the a))pear-
auce of the protoplasm, most advanced itear the axone hillock.
These chaufjes consist, as has already heeu stated, in a hreakintr
up into tine granules of the tijrroid masses with diffuse stain-
ing of the achromatic suhstatice of the coll. If the changes
ho very marked, as is often the case in young animals, the ti-
groid massi's may disajipear from a large portion of the cell hody
and the nucleus may ho displaced to the side of the coll. As a
* Mnriiie;
■foiKJaire.s el
TIIK NliriJONK AS 'IIIK IM'r,
ynn
result, the typical Hticlioclironic iirnuiffciiiciit of tlic li^nnd a^-
^Tcpilioiis inside I lie liody u\' tlie c^ell is eidirely lost, in latis
st;i|jes in the dendrites also, iind what staiiiahle suhstanee is
left a|t|tears in the I'ortn oi' line diistlike particles or as a dilTuse
hlne stain (i"'i;f. 174). These secondary tdian^'es in the cell
liodies of neurones, the evidence ol" " reaction at a distance,"
may lead !<» the death of the cell in case the peripheral connec-
tion can not h(( aj^ain made, although more often after a
certain lenj^th of time tluuv is u {i;radiud restitution of the nor-
mal appearances, due, Nissl thinks, to the forinati(»n of new
connections. Accordiuf^ to Marinesco, ther(M)ccurs durin^^ the
process of repair proj^ressive hypertrophy of the tu-rve cell up
to a })eriod as late as ninety days after the operation, lie he-
VwwH that this increase in size of the nerve* cell is for the pur-
j)ose of assistinfX in the re|»air of the lesions in the divided
nerve, and thatconiplete return cd' function occurs only after
the anati>niical continuity of the [teripheral nerve has hoen re-
established.
'The chauffes in the cell hodies fcdlowing the dirtn^t action
of toxic suhstances upon theni dilter, as a ruhf, markedly from
those just deserihed. Without j,Miin<f into a detailed (h'scription
here it may he jiointed out that the (diromaltdysis under these
eircunistanees he^ins, as a rule, not inside the cell hut rather
at the periphery of the cell body ami in the dendrites, extend-
injj: },'radually toward the nucleus. Marinesco* has laid f^reat
stress upon this point, and has hrouj^ht forward in evidence* tlu!
changes whi(di occnir in exjuu'imental ana'tnia after lij,'ation of
the aorta (l''iff. 17:5, ri</i' supra), in hydrophobia, in acute ex-
perimental uraMiiia, and in other conditiojis. lie states also
that in addition to peripheral chromatolysis in primary lesions
of the nerve cell, instances are met with in wlii(di the ciiro-
inatolysis isdilfusc; and others in which it is perinucdear.
My own studies, nuide o!i several forms of intoxication with
mineral poisons, on cerohro-s])iiud menin<fitis (Fig. 175), siiul,
in conjunction with .1. Krlanfjer, on the facial nu<deus of rab-
bits after section of the facial nerve (Ki<f. 170), and on tin* motor
c(dls in the ventral horns of the spimil cord after (extirpation of
the bi(!eps muscle, so far iis thoy have gone, support these views,
* Marinesco, G. Piitliolii}i;i(' p'm'nili' <](• In cellule nervtMise ; lusioiis se-
•con(liiire.s et primitives. I'resse lued., Pur. (iHD7), [)[>. 41-47.
m
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iiit
296
THK NKKVOUS SYSTKM.
altlioiifrli witli ciTtiiiii iiioditlciitions iiiul rcsorviitioiis. The
iiiiiiii t'lnpliasis in the " secoiuhiry " lesion is to be laid upon the
fact that the process begins near the axone hillock. Less impor-
tance is to be attributed to the peripheral chronnitolysis in the
Fl(i. 17.').— Cells from tlic huiiiiin s|)iiml cord in tiiiilciiiic (■crchro-sitiiiiil iiiciiiuKitis.
,1. two cells In ilie ventnil horn. The imcleiis of one of IlieiTi is not visihle :
thiit of the olh is (lisphiced to the tide of the cell. Marked disorfriinization
of the stainnhle siihstance of Nis.sl. the secondary result of the involvement
of the ventral roots hy the meningeal inllammation. /(.cell from the nucleus
dorsalis showing' alterations which result from a lesion of the a.xone of the
cell.
! 'S
TIIK NKIUON'K AS TliH TNIT.
2J>;
" primary " lesion, since in ricin pois(tning,* for example, elmnjres
may have occurred in tlie N'issl bodies tliron<,diout the cell l)ody
at a very early period, even het'ore there is actual chromatolysis.
In the study of the ])athological anatomy of human cases the
^■,_../:^;-';>.V:
Kui. 171). — Kdiir nerve ccHs rrom the nucleus iiervi faciiilis of a rabbit fifteen days
after section of the nerve root. Drawiuf; inach' from oni' of ,1. Krlaiifrer's
prepaKitioiis.
results of such investigations should at all events be borne care-
fully in mind, and it will be the duty of the pathologist to en-
deavor to distinguish in the various forms of nerve lesion the
alterations which depend upon " reaction at a distance " from
f\
* Stucliod in tissues of exporitnentnl uiiinials kindly supplied by my col-
league, Dr. S. Flexner.
2J»H
TIIK NKUVOl'S .SY.STKM.
Fio. 177. — Siniil.'irity (>r<'linnf;t's iivihIiu'imI in cell liodics dI" lnwcr iiuitor nciironrs
(11 l>.v iiiltiiif; tile Mxoiii' :nnl i~Mtiy cutliiifj tlic (•(ivrcspniiiliii); ilmsiil rimts.
(ACtcr \V. H. \V;iiiiiigtoii, .1. I'liy'siul., Ciiiulir., vul. xxiii, IS'.ls, pi. i, l"i«.s.
1.
and ;<.
.\. li nuniial n
)!' tlif vi'iitr.il lioi'ii : |{, vciitial Inuii cell
t'limti't'ii (lays after scctinti of iiiii(".i)(iinliiif; vcnlnil rimt ; ( ', <'cll (Vinii (liirsn-
lalonil unuii) of xcntral
.sil roots of the cauiia t'H'iina.
Iwcnty-tliri'i' day.saftor section of sovoral (Ui
TIIK NlirWONK AH TIIK INIT.
20U
tlioHf wliicli lire iIm' itsiiII i>\' iIm' ilii'i'ii iirlioii iiT iitivsi' in hmIii-
tioii ill till' 1)1 1 iiikI lynipli ii|ioii llir irll liiiilit'M hihI di'tiilrilcH
ul'llii' iicui'niH'H. Ill I'i'i'ttiiii |iiil IidIo^mciiI I'liiiililioiiH till' inii-
iniif iiiiiv (IdiilillcHH lit' iilTcflt'd in ImiIIi wiiys Hiiiiiilliiiii'oiisiy.
I liiiv*' riMinil tliiM to 1)1' triK' ill <'|iiil<'iiii(; iM'i'('lini-s|iiiiiil iiiiiiiii-
gitiH.
'Till' li'HiniiH in tliiM ilisniHi^ in the nAln (if the vcnlnil linrtiH
iin> in |itirt tlniHc of rcurtioii at. u ilistiini'i', in |iiirl lliosr of pri-
niinv inliixii'iiiinn nl' tlii> nri'vc ct'll. I iiin ol' llii> ti|iinioii tliiit.
I lit' Iniincr si'i (if li'sidiis wliii'li liy the wiiy iin- liy t'lir I lie nmif
|in»iioinnTil iirc I lie rcmilt of injury to the tiiolor iimiIk liy IIh'
ini'iiingi'iil intliiniiiiiil idii, t III' lattrr tu llii' ^'I'licnil to\ir I'lTi'i't
of till' |M)iHonH |ii'(hIu('i'(I liy llir liucloi'iii wliicli ciiiiki' tliii
(lisi'llHO.
Ili^dily iiilt'rc'Hting in this luinncction iiro the rcHiiltH nl)-
tiiincil by Wiirrinj^toii,* nl' iiivcriMMil. Hit liuHiMit. the <liirHul niotH
(if H|iiiiiil iici'vcH I'min Mic lil'tli to llio ninth tlionuir ini-liiKivit,
iinil wtinlii'il HcclidiiH (if t he viiiiniiH HCLrinrnts of the conl hy
NisHl's nii'thod. lie foiiiid tiltrriit.ioiis in a lai'^'c nnnilM'i- of
(■('IIh in t lu< Hcvdiit li iind iti^htli Hc^tiicnlH, cHpcciuily in Mi<> dorso-
latcral f^roii|i of cells in I host' si'ifincnts. In the inonkcy a
^M'cat many tells are found ultcreil on tlitMipiMiMilc siile. 'I'lie
alterations, iis will lie seen in \'"\}f. 177, are similar to the
t'liaii;^i's wliieli result when the axolies of these ttells are eiit..
\\arrin;:lon alt rilnites the chaiij^'e to the withdrawal of the
alTereiil impnlsi^H which normally impin^^rt* on the eornnal cells,
anti compares his resnlls with those olitained from the well-
known t'X|ierimeiits of Molt, and Sherrin^fttni,! hy which it. was
shown that section of iJie dorsal roots leatls to pronoiiiici^d loss
of inuscniar tone, ataxia, and marked im|iairmeiit of voluntary
movement. TheHe Htudics of Warrington, tak(!n with those of
Marinesco and van (Iehn(diten,J should make lis keep in view
the possibility that the lesion hitherto supposed to be typical of
* W'lirriiiKtnii, VV, 15. (in llic SlriHtliini! AlltTHlioiis obHtTvet! in Nerve
Cells. .1. I'liysiol., ('iini.ridp', vol. xxiii (iNilH), pp. 11!> 12!».
f ISidtt, I'. W., Hint ('. S. Slicrriiif^liiii. i'lxpi'i'iiiiciils iipnn Ihc [nflurncc of
StMisory Nerves upon Moveimiit ami Nutrition of I lie Liiiilw. i'roc. Hoy.
Sof. liond., vol. Ivii (IHliri). pp. :iiri-lHl.
I \'nii Oi'lmclilcn, A. l/iiiiiitninif fine dc In ('ciliilc iiiTvciisc. XIIlli
Coii^ivH iiiteriiiitioniil tie iiK^di'ciiie Ti iMoscoii tH07, liefer, iiii Neurol. Ccii-
tiullil., I.eip/,., Hit. xvi (1K(»7). No. li>.
'ii!i
*to;.|!
i
!
'ji«
II
;ti)o
tllK NKUVors HVMTKM.
w vt>ii(iii»n Hi n iliMim^ro ihic toliwion of tin imuit' nni\ ili'iiowl
u|>i>n im iniivi'lv ilitTi'H't\l ciniso iiiitnclv, llu- iciiHnnl id iilVn
cnt mipulm'H fioiii ihr dcmlriti'H iiiui i-t'll IukIji'm nl' the itrnriincH
roniTinnl
\t\ mli'Vi>s<in!r pvoMnn for ri'MiMivi-li in iimtu-rlioii witli in
iKM. iniiu\s bits pvt>l>!il>l\ iiliciiilv mifmcMfnl ilHi'll' titlhr iniitiliol'
uinnv- H" solnMc \o\w 'j\ilist:)nc("( im<> i'!ip;»l>li> of piodni'in^: w il li
\\\ )i lonipsn-.M nt'l\ <hoy\ pnioil of linii- iilti'V;t1ion« «itliin llto
t\(Mn-onon winch mo liisioloj^iirjdlv roooyni'/nldo, llio i|nos(iot»
avisos, \\\\»\ \\\]\W \hv olYool of juttnitii^li'vin!' ii snoiillo ;inl ilo\
ino Ht »lu" sinno tinio «s. or sijI^siMpnnilv (o. \\\v inlroihulion of
i ' .^
K
Via. ITS 1vflf<^-ts of p<'>'s<>"iiS witli nmliDViiilvil. i Artvv ,\. U<i1dsr1\oiilor «. K
1S<»s. TmC iv. Vif 1
tho toxir subsfanoo ! Al llio «iito of writiuji' ^'•i^ly a f«nv n^soavoho!*
which havo a iliiv. t boaring n|•u^n this 1o
^JM«
no boon tn.uio
Till'; NMIIIMNK AM I'lll'; I'MI
HO)
tllllllrU, lllllHI' III I illllJMI llljljl I mill I'llllllll' ll|lllll |Mli.-4MlllMl(
v\illi Miiiliiii iiilril iitid ii|M)ii IctiiniH iinMuiiiiig, lli)mi> nf iVliiii'
S,
•■/
m
A
l|
^l--./-
t.
V
I'm Kii i;il'fi t'lol ■■iilllli l;il Iiiiii'ihi'mI lic.cly (i iii|iiriiliiii I Mill \ U.ilil^i hii'lii
II I; riiliiii, Nniiiiiilr iiml lull IkiImi'Ii III \iiiiliiiiiii' i|i r Nii vi ii/.i Hi ii. ili .
III! I , I'^IIM. I'll I \\ , I' ii! '.' \ VI iiliiil Ikii II 1 1 II >•!' Ilii' lull' I II I i!iiiii|i is mIhiwii
HINill Mini ('llMlltl'lllI'M'JI' t ll|Mi|l ll'tlllllM Idxillf II III I II II t i I O X I llC,
iiinl ol' KiMiipiirr iiinl ruliiirk | mi Iml iilisiiiiH |iiiiM(Miiii^r ll in
♦ (idliNi'lii'iiliT. /\. mill V, I'llllllll. Ki'iiiiliiKM iliT Sliiifliir ilir (liiiiL'liifi-
/I'lli'ii (\ iii'lriiK vim (liililsclii'iili'i), \'i'ii'iii I'l'ii Imiii'Ii- Mi'iIitIii. IIitI I<Iiii.
\\ I'litisclir. ( IMU'i"). S. ','Mi. Also, NiHiimli' iiml |iMlliip|iii,'i-ii|ii' Aiinldinii' <I'T
NiTVi'll/i'lli'll, llrriiii, IHIIM.
f t 'lllMllrllli"':'<r rl !Miirilir'<i'ii. Id's ir";ji)llH llJKtdlniriiiiii") OxfM ilr In ci'llilli'
iii'ivt'iisi' iliiiiM liMii's i'ii|i|inrls iivi'r ll' i|i>vi'|ii|i|ii'iMi'iil ilii Ii'Ihimi'< rl riiiiiniiniti'-
imli t(''liiiiii|ii(' I Alwlr.|. Hull, il iih'Iii. Snr. mi'il, il. Iic'p|i, ilr fur., '.\. s., t. xv
nMllHi. pp. !lll KM.
t Kt'inpiirr, W. iinil ll. I'lillnik. I>ii' Wiiliiiin,' i|cs Untiili-imiHloxIns
(l''l('isi'lii;ifli'H) nml -ii'liiiw •^pi'cill'^cliin ;\iililipxiiis imf i|ji> Ni'rvi'ii/i'll<'n.
DiMilsilic iiiimI. Wiliii-^ilii.. I.i'ip/. II. UimI., IIiI. xxiii (|M));>, S. 505 .-i07.
!
302
TUE NERVOUS SYSTEM.
known that if niiilon-nitril bo injected into a rabbit, liydro-
cytinio poisoning quickly results, leading to the death of the
animal, after from twenty to thirty minutes, with paralytic and
dyspnu'ic phenomena. If, however, the aninuil has been in-
jected a few minutes before with a solution of hyposulphite of
soda it quickly stirs about and recovers. It is supposed that
the sodic salt acts as an antidote by giving off sulphur which
unites with the cyanogen radicle. In animals killed with
malon-nitril distinct alterations in the Xissl bodies can be made
out (Fig. 178). In animals treated with the two substances and
killed after nineteen hours certain alterations in structure are
still apparent, though after seventy-one hours the cells are again
normal, f Vlscheider and Flatau have compared the findings
in such instances with those resulting from the artificial heat-
ing of animals in the thermostat up to 42" or 44°. If the aninud
be taken out before death it is flaccid and incapable of moving.
The ventral horn cells of the cord examined at this period are
seen to have lost their normal structure ; the tigroid bodies are
replaced by light-brown opaque masses and by single granules,
the whole cell being enlarged and the dendrites swollen (Fig.
17!i). If the overheated animals be removed from the thermostat
and kept alive, gradual restitution of the normal structure can
be made out afte several hours (Fig. 180), though the repair in
the cells is not so rapid as the reappearance of function would
lead one to believe. While the animals appear to recover very
quickly from the symptoms, the regeneration of the cells after
the nutritive disturbance requires for completion at least several
days. It is evident, therefore, that changes in the chromatic sub-
stance alone, as many have long suspected, do not suffice to ac-
count for the clinical phenomena associated with them. All the
evidence goes to prove that the f unctioii of the cell, as has already
been pointed out in Section III, must be intimately associated
with the integrity of what we call the achromatic substance.
Marinesco and Chantemesse have studied guinea-pigs injected
with tetanus toxine with the object of investigating the relation
of immunity to histological alterations in the cells. After in-
jection of the toxine alone they found typical alterations in the
cells of the ventral horns, quite like those which have been de-
scribed by Xissl, (ioldscheider and Flatau, and others (PMgs. 181,
iS'-i). After injectiim of tetanus toxine and antitoxine they could
find no alterations in the cells after three days, but if the anti-
i
1
THE NEURONE AS THE UNIT.
3u;i
toxic serum were not injected until twenty-four hours after the
injection of toxine, (listliict alterations in the cell bodies of the
neurones could still he made out, although it is stated that these
were less marked than when the toxine alone had been injected.
The various changes in the nucleus aiul nucleoli, to which
considerable attention has been already directed by a number
of investigators, afford, to a certain extent, valuable informa-
tion concerning the state of nutrition of the cell, but they must
here be passed over without further comment.
f
^^.
W
V\i\. ISO. — Ri'covfry <(1" ventral liorii cell from cliiinjrcs imiduci'd l).v iirtiticiul iii-
crcasi' of Imdy t»'in])<'niturt'. ( After (iohlscliciilcr and Flalan. Norniali iind
liatln)lof;is(li(' Anatomic der Nerven/ellen. etc.. lierl., ISiKS, Taf. v. I'My. 'J.)
Tile lifinrc sliow.s a ventral horn cell of the lateral Knuii) after eiglit lioiirs
and a lialf of restitution.
A warning concerning the necessity for obtaining very fresh
material when Xissl's method is to be employed for studying
pathological alterations may iu)t be superrtiu)us. Kot only nniy
lesions in nerve cells change in appearance in pathological
cases a short time after death (Marinesco), but normal cells
may by post-mortem tdtenitions come to resemble those altered
as the result of disease. We have to thank Meppi,* of Tram-
* Ncppi, A. Sul • nlternzioni ciulaveriche delle cellule nervose rilevabili
col metodo di Nissl. Kiv. di patol. nerv.. Fireiize, vol. ii (181)7), pp. 152-155.
El'.
••a;
WM
i!
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mm
'ipM!^i
iiO-t
\.
,^
TlIK NKUVDl'S SVSI'KM.
•'^N
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<?rjtf5v
'» ♦,
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♦r-^.
/*
tfi^i
•'^i
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rl
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N« .1
/.is'<«7
/./tf^
B
h^
I
Vl<-, 1S1. KiVccts
if ti'tanns tnxinc iijum (lie lowtM- nmdir lU'iivmics i At■|^'^
(I(>lc^sl liculcr Mtid FlMtMU. N'oniiuli- iiiui imtlioldirischc AiiMtuniic lioi- Ncni'ii
/I'll.'ii. ifc,. l?.-rl.. 1S!)S. Tat', vi. FIl's. 1 miuI •,>.■> A. nnnniil motor vrnlnil
luirn ('I'll lit' till' nititiit. sliowitm tyi
iiu'lliod. li. vi'iitnil li<
)U'iil stnictiirc a?
lit'innnst rated liy Nissl'
II two linui-s at'lcf intravciiDiis inicclinn of O.OJ
(1 ci'iii., 4-t)i>r-i'<'nt siitiitiiiiO Iftamis toxinc, Tln" innli'dliis is swullcn ami
iif a lighter I'ulur |)iaii
Till' tiLTiiiil iiiassi's arc
wliat pall'. llioiiLili tin- arr;iii!.'i'im'iil is well jin'scrvril.
11 ami
TIIK NKllfONK AS Tlli; TNl'l'
1^1680
305
■
tlHHk^
■Hi
'^^^IBi
IHl'i
'4'Pi^^B
HBI/
::i^^HH
■
; 1 1 !
•'■1'!
■■,.'■»
S-"\
/
/ tfsy
n.
fi /J»nr'/^ ^'z ,
I'll.. IS-.'. More iichiincrd st:ii;(s nf |iiiis(iiiim,' wil li lctiiiMi> lii\iiic'. .M'trr ( Icild-
sc'liridiT ^iiiil I''Im(iii. NcirniMli' iiiiil |iMlli(ilip};isclir .\ii;ilcpiiii(' dcr Nirvcii/illcii,
rlc. I?('fl., isiis, 'I'iif. vii, I'Mi-s. 1 Mini '.I.) II. iiiTvi rrll Croiri mi Miiiin.il (ivc
cl;i.vs iil'd'r ;iii iiiji rlimi (iC (MHIKI ( I (■ciii.. soliil inn l:ti()0) IcImiiiis Idxinc. 'I'hi'
ninlcdliw i'^ niiiikicllv >\v(illiii : I he li'jinid licidic'- iirc iilsci iniirli .swnllcn. mi id
fire iiiiinircslly lircMkiiiL' up and iirr liccdiiiiiii,' iiilifiiiiimlrd. /). nrrvf ndl
IViiiii Mil MiiiniMl I wcnly-iiiic liiiin'^ Mnd ;\ iinarli r mI'Ii r injiitiiiM id' O.ol M
rem.. l-pcrMM'iit. siiliitiiiii t (cImiiiis loNiiii', 'I'lic niirlidliis is di riniiird. Tilt'
tiKfiiid niMsscs slinw tlir lin(dv ki'miiiiImi' disiiilcmMtiiin.
21
I ►■
I
I
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V
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r
J^S
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fill
liJil
:'^!^fi!l!H
3(»r>
TIIK NKRVOUS SYSTEM.
biisti'a laboratory, for a report on the changes, revealed by
Ninsl's method, whieh take place post mortem in normal nerve
cells.
Since Meppi's arti(de another on the same subjecit has ap-
peared by Harbacci and Campacci.* A. I loch states that the
Hetz cells of the paracentral lobule are very resistant to post-
mortem alteration.
None of the methods at present at our disposal suffice, how-
ever, for more than the discovery of what must be relatively
extremely gross alterations in the structure of the nerve cells,
and we can only hope that er(^ long advances in cytological
technique will permit a deeper j)enetration into the mysteries
of nerve-cell organization.
These considerations bearing upon the physiology and pa-
th(»logy of the neurone have led me further than I had inteiuled ;
they must now be brought to a close. A series of phenomena
have been touched upon, all too briefly, I fear, to do justice to
them — Wallerian and Tiirck's degeneration, the changes in the
nerve centres following amputations, the experiments of von
CJudden, Bregman, Darkschewitsch, Nissl,and Flutau, the eifects
of injury to the nerve centres through cuttij;g ofT of the blood
supply, the effects of acute and chronic poisonings of the nen-
roiu's, the phenomena of regeiieration, the incessant activity of
the nervous structures, the absence of proof of any actual spon-
taneity in the elements, the doctrine of tlie specific energies of
nerves, the unity of nerve functions in the neurones, the direc-
tion in which impulses are transmitted, and the iiitluence of
activity, fatigue, repose, poisoning, etc., upon the structure of the
nerve-cell protoplasm. This cursory glance, however, over nuiiiy
phases of the metabolic and nervous activities of the neurones
may have sufficed, I hope, to throw tlie essential ])()ints c(»n-
cerning the nutrition of neurones into relief. The changes
characteristic of tiie degenerations of Waller and of Tiirck
prove to us that no matter how important the medullary sheatli
may be in the integrity of the neurone for the nutrition of tlic
axoiu^ inside it, it is certaiji that this Mitluence alone or to-
gether with that of the nutrient supplies arriving through tiie
nodes of Ranvicr caji not suffice for the maintenance of the
♦ Marlmcci. (\. c (i. ("ain[iii<'ci. Siillc losioiii CMdiivt'i-ichc dcllo ci'lliilc
nervusi'. ]{iv. di pntol. iierv., Firenze, vol. ii (18!>7), pp. ;i;fT-;547.
In
k
vsmm"
TIIK NKUllONK AS TIIP] UNIT.
807
lu'iilth of the nerve fibre. There is not a little evidence, in-
deed, favoring the view that the medullaiy sheath depends for
its nourishment upon the axone, rather than that the axone is
nourished from the medullary sheath. Some influence or influ-
ences from the rest of the neurone, particularly from the cell
body, are essential to the well-being of the nerve fibres. What
is the nature of this influence or of these influences ? Does the
axone actually receive all its nutrient material from the gan-
glion cell, or does it depend, as would seem a priori much more
likely, for the most part upon autochthonous metabolism,
needing only the influence of the cell to which it is connected
to govern the assimilation ? These are questions for which tlie
data at command do not permit as full answers as we could wish.
Every one must grant that the peripheral nerve fibre takes vd^e
in large part of its own nutrition ; the presence of vasa ner-
vorum affords sufficient warrant for this belief. Further, the evi-
dence for its subordination to local processes of diffusion is to
be found in the local injuries to peripheral nerves resulting
from the circulation in the blood of soluble substances of a toxic
nature — as, for example, in diphtheria. The key to the whole
problem undoubtedly lies, as the neurone concept teaches, in
the fact that the axone in all its parts, no matter how far re-
moved from the cell body, is an integral part of a single (;cll.
To explain the influence of the cell body upon the fibre, fiold-
scheider has advanced a very ingenious hypothesis. Tie sug-
gi'sts that it is most probable that there is an actual transport
of a material, perhaps a fermentlike substance, from the cell
along the whole course of the axone to its extremity, and that
(irst through the influence of this chemical body the axone is
enabled to make use for its nutrition of the material placed at
its disposal in its anatomical course. Schiifer sees in the loss
of the influence of the nucleus the importaiit factor in celliilif-
iigal degeneration of a severed nerve fibre, but attempts no ex-
planation of the nature of the nuclear power exerted.* Per-
sonally, I rather favor the view advoc^ated by von Lenhossek,
* To gain HI) idea of tlie recent eoiiceplions coneeriiing tlie relutioii of the
nucleus to nutritive processes in tlio cell the article of Ilaberlanilt (Ueber
die He/ieliunf^en zwisclien Function iind Liifi;e dcs Zcllkorns be! den Pflim-
■M'M, Jena. 1887) ami that of Kors<'iiclt, (Meitriifje z.ur Mnrplidloirip uud I'liy-
siolofifie des Zellkernes, Zool. Jahrb., Abth. f. Anal.. Ud. xxvi, IHS(i) nuiy bo
consulted.
'»!il
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lid /
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r '^1
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i
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ii
61
I t
I,
I!
308
TIIK NEIIVOUS SYSTKM.
a^?miili^i:
nij
that instoiid of assuniin^ an iiotuiil triinsportation of a clu'iiiiciil
8iil),stajic(! wo can very woll conceive of a variety of excitation
whicli, startin<i; from tlie cell, pei'liaps even from tiie nucleus,
streams constantly through the axone, and in it in some way,
perhaps by a process comparable to electrolysis, maintains the
chemical conditions suitable for the assimilation of the nutri-
tive juices, a view entirely com[)atil)le with the fact that the
trophic action of the cell body ai)pears to l)e h'ast active in the
parts of the axone most distant from it. (ioldsi-heider has
argued that sintse peripheral sensory libres (in which presum-
ably the im])ulses are, in the main at least, centripetal) degen-
erate comjdctcly when cut through, just as do divided motor
libres in whicli the impulses are centrifugal, the influence of
the ganglion cell presiding over the assimilation is not identical
with the functional excitation, an idea which Kumpf* had as
early as 188"3 satisfactorily stated. In view of what I have said
before coucerinng the j)ossibility of functional excitation in
either direction in a neurone, this argument would lose some-
thing of its force; but, granting that it is well based, it lu'cd
not militate against von Lenhossek's liy])othesis, inasmuch as
in the absence of the passage of genuine nerve impulses cellu-
lifugally in the i)eripheralsi'nsory fibres the transmission of the
excitations essential to nutrition would still be conceivable,
and would certainly be no more ditlicult to conceiye of than
the actual cellulifugal transport of a chemical substance in a
direction opposite to that followed by the functional excitation.
The more thought one gives to the subject, the more he will
find in the trophic rehitions of the neurones to make him hesi-
tate before he denies the possibility of the conduction of im-
pulses or intlucjicos in either direction throughout the neuron(>.
Hut hy})otheses such as have just becTi considered will not
suffice for the interpretation of the findings in the main body
of the neurone after division of its axone — those included in
the delicate experiments of Nissl, Flatau, Marinesco, Krlanger,
and others, as well as those in the earlier studies of von (iud-
den and his pupils, and in the observations upon the nervous
system after amputations. We liave seen that these obser-
vations have, partially at least, annulled the validity of W'al-
* Itmiipf. 'I'll. Zui- Dci^iMicnitioii durcliscliiiitteiuT Xerven. Untersuch.
u. (1. ])liysiol. lust. (1. I'liiv. llfidelb., lid. iv (1882).
TlIK NKl'UONK AS TIIK INIT.
30U
ler's (locrtriiio of the trophic ri'lationa of the norve cells, for
after injury to iiii axone, in luldition to the dej^eiienition in tiio
iixone peripheral to the lesi<»n, therc^ are (lemonstral)h' altera-
tions in the (^ytoproximal end of the uxone and especially in tiie
cell hody of the neurojie itself.
Marinesco, in his careful study of the nervous system after
amputations, attempted to account for the discrepancy. Al-
thoufifh up to this time the spontaneity of nerve function had
scarcely been (juestioned, this author threw doubt upon the
autonuitic activity of tiie nerve cell. It was his idea rather
that tlie functioiuil activity of a nerve cell was entirely depend-
ent upon stimuli reaching it from the outside, and that in tlie
absence of the a«lvent of external stimuli the spinal ganglion
cells, for example, can not retain their nutritive functions. He
was more cautious in his explanation of the atrophy of the
ventral horn cells, but suggested that in case a limb was ampu-
tated, eveji though the path carrying voluntary inii)ulses to the
motor cells in the ventral horns remained intact, the one which
l)rought the sensory impulses concerned in reflex activities was
interfered with, and the dimii\ution in impidses reaching the
ventral horn cells thus brougiit about could, he thought, result
in a marked depreciation of tiieir vitality, (ioldsciieider, in
ins article dealing with the do(^trine of the trophic centres,
accepts fully this hypothesis of Marinesco and in a way extends
it.* Von Lenhossck, who is favorably impressed by it, does not
l)elieve, however, that the loss of centripetal stimuli reaching
the corresponding segment of the spinal cord by way of the
sensory fibres coming from the muscles, tendons, etc., after
injury to a motor nerve,f will suffice to explain the alteration
in the cells of origin of the fibres cut through. While 1 can-
not agree with von Lenhossck that there is no physiological
basis for the view that these stimuli influence the motor cells
which lie in the same segment of the spinal cord, or that no
reason for such a relation is visible, it must nevertheless be
granted that in his attempt to offer a suitable explanation he
has called attention to another possible factor which may be of
decided import as regards nutrition. He finds the simplest ex-
i
/i
* strong confirmatory evidoiico lias since been adduced by Warrington
and van (M'huchlcn. Vide supra.
f Cf. Nissl's experiments.
■ i!
»
-'il
I, ts
'm
< '
310
TIIK NKRVors SYSTEM.
plaiiiitioii of tilt' »l('jj;cMU'riitivo plu'iKiiiiciiii in quostion in tlio
ussuiinitioii tiiat for I'vcry norvc cell a lu'Cicssary <'t»ii(lition of
existence is its normal (fonnt'ction witli its end orj^an by means
of its axonc — for exami»l(', in the case of a Oell of tiic ventral
horn witii its corrcspondinj,' nuiscOc. In the ciittinff tlironfj^h of
a motor axoni' it is, accord in<,f to him, not tlie h)ss hy tlic motor
cell of the few centripetal stimnli wiiich this nii^dit occasion,
but rather the impossibility of a normal dis('hartj;e of energy, the
nerve cell being, as it were, end)arrass('d by the storm of excita-
tions reaching it by way of the rcllcx collaterals, fibrils of the
j)yramidal tracts, or other connections. Flatau, in his dis(;u8-
sion of the sid)jeet, takes a nudway position, believing that the
nutriti(m of the ganglion cell may be affected either by diminu-
tion in the number of impidses whi(^h it receives or by the coii-
sequent impossibility of the giving off of stimuli to muscles or
to other ueurones. This certaiiUy is a very rational position
to take, iiuismuch as in
a society of cells, just as
in any other commu-
nity, if one member be
dejjrived of the intlii-
eiices of its fellows,
or, although receiving
such inthuMices, become
glutted with them,
owing to inability to dis-
charge its own func-
tions,that nu-ndu'r must
necessarily sutTer.
Still another hypothesis has been advanced by l^ugaro,* who
has studied the alterations in the spinal ganglion cells after
section of their peripheral (Fig. IH'.i) and central (Fig. 184)
axones. lie points out that the motor axone and the peri])h-
eral prolongations of spinal ganglion cells differ in that they
are placed at the opposite extremities of nerve elements. This
very position he suggests nuiy be of especial influence as regards
■ /5 '--'•.■:■'•;■> ."^ •::.:. i:^. •■
Vui. is:?. Si>iii;il jiiiiiKlidii cell sliowiiif; iiiiirki'd
altcnitimis rulldwiiitr scctimi of the sciatic
nerve. Siihlimate lixation ; tliioiiiii stuiiiiii^.
(After I.li^'ari), )
* Lugaro, E, Sullc alterazioni dellc cellule norvose dei gangli spinal i, in
seguito al taglio della branua periforica o eeiitrale dol loro i)rolungaineiito.
Riv. di patol. nerv.. Fiivnzo, vol. i (18!)6), pp. 457-470; also, Sid coniporta-
niento deile cellule iiervose dei ganglei spiiiali in seguito al taglio dolia
branca eentrale do loro proluiigauieuto. Ibid., vol. ii (18i)7), pp. 540-543.
TIIK XKUIIONK AS TIIK INIT.
311
(listiirl)iui('(M of imtrition. Ho thinks that either suppresrtiou
of (he stiimili normally arriviiif; in tiie group of nerve elements
or iiiipi'diiiu-nt to the (lisciiarge of
energy from u group imts by (lis- .'^J»*'*{55r*'^ ^.i -
turhing the nornuil uction of the •f'^^^i^L^'^^'^y:-
he niiuU!OUt in the cell bodies in-
side the spinal ganglia, after se(v
tion of the fibres of the dorsal root
l'"ui. IH-t.— spinal «aii«liiiii ii'll
flirty iliiys ai'trr scctinii nt' rnr-
n'S|Miii(liii}; iliirsil rmil. Siilili-
iiiatr tixaliiiii: tliioiiin staining'
( Al'ti r l.ii^'ai'o. I
of a spinal nerve or its intramedul-
lary prolongations oidy insignifi-
cant ehangt's or none at all are
to be found in the (^ells. In order to explain this apparent
paradox he suggests that the various elements of the nervous
system offer varying resistance to nutritive disturbances. He
can imagine that the sensory elements suffer more es})ecially
from the suppression of external stimuli, while on the other
hand the motor elements suffer mainly as a result of liindrance
to the discharg(! of energy elaborated within them, and which,
under normal circumstances, is removed immediately from the
centre where this work is done. It is Lugaro's opinion further
that the recovery of certain cells in the spinal ganglia and the
pernument alteratiojis or complete disintegration of others is to
be exi)lained by the assumption of variations in native regenera-
tive capacity in differejit cells.
'I'hat the injury resulting from whatever cause, if only tem-
porary, need not be fatal to the neurone concerned, is fully
iiulicated by the general work which lias been done on regen-
eration of peripheral nerves. P^ven though the preliminary
signs of neurone decay can be demonstrated by the method of
Nissl, the trophic function is not at first lost, inasmuch as
strenuous efforts toward repair are made,* and should the axone
* Tliis is a|)|)anMitIy triip ovimi iiisiilc tlie central iutvous system. Cf.
WiiiTi'stcr, W. Ij., On ivcj^cncraliiin nt' Xcrve F'ibrcs inside tlie CtMitral Ner-
vous .System. J. Xerv. timl .Mini. Dis.. N. V., vol. .\xv (1H<J8), p. G9H.
f;
1
i
' '^'^
:
. t!
m\im
«12
TIIK NKKVors SVSTKM.
happily Huccccd in rc-i'stiiblisliiii;^' its tcriiiiiiiil rcliilions tlicrt' is
^nidually a (Hnuijlctc ri'stitiitioii to tlic normal coiiditioii.
Only wlu'ii on account of some obstuck's in the way, or tliroujfli
H(»m(' otlicr cause, this rc-cstal)lishnu'nt of the former or other
conduction relations of the neiironi' is rendered impossible, do
complete de<;eneration and disappearance of the neurone occur
after section of tlio uxone. With the peripheral sensory uxones
the trophic etTort manifested is often extreme, as many unfortu-
nate individuals have found to their discomfort in the aj»pear-
ancu of the so-called amputation neuromata.
u
SKCTION VI.
.'1
■I
/I
ON THE GH()rPIN(i AND CHAINING TOfJKTITER OF
NKT^RONKS IN A COMI'LKX NERVOUS SYSTEM MKK
THAT OF MAN AND MAMMALS.
Introihc TioN. Cliai). X.WI.
SiHSKiTioN I. Nt'uniiies conncptinp tho souse organs of tlip body witli tlm
('('III nil nervous system (periplieriil ('ciitriiietiil iieiiroiics ; sensory
neurones of tlie first order; sensory protoneurones).
('liissificntion of sensory impressions. Tho neurul scf^finont.
Pliysiolof^ical mid clinieal studies, ('hup. X.WII.
A. Centripetal neurones of the lirst order coileetinj; bodily im-
prossions: 1. 'i'lioso connected witii tho spinal cord. {!haps.
.X.WIil to XXXIV; 'l. Those connected witli tlie rhomlien-
cephalon, Chap. .\XXV.
H. Centripetal neurones of the first order coUectinfj impressions
of special sense : 1. I'eri|)lioraI j^iistatory neurones; 2. Periph-
eral olfactory neurones, Chap. .\'.\.\\'I ; •\. Peripheral visual
neurones. Chap. XXXN'll : 4. Peri]ili(Miil auditory neurones,
Chap. XXXVIIl.
.Sluskctiox 11. Xeiirones within the central nervous system connecting tlie
end-stat ions (nuclei terminalos) of the uxones of tho peripheral cen-
tripetal neurones with other portions of the central nervous system
(sensory neurones of tlii^ second and of liiglier orders).
A. Central neurones of sensory condiietion paths other than
those correspond iiijj to the orpins of special sense: 1. Those
pertaining to the spinal peri|)heral sensory neurones — («)
Neurones the coll bodies of which are situated in the nuclei
funiculi fj;ra('ilis et cuneati. Chap. X.XXIX ; {!>) neurones the
cell bodies of which are situated in the nucleus (lorsalis,Cha|i.
Xfj; (r) neurones the cell bodies of which are situated in
the gray matter of the cord, tlie axones going to the fascicu-
lus ventro-lat oralis (Jowersi, Chap. XLI ; ((/) neurones the
cell bodies of whieh are situated in the gray matter of the
cord, tho axones going to the fasciculi proprii. Chap. .XMI.
2. Those pertaining to the cerebral peripheral sensory neu-
rones — (o) Neurones the cell bodies of which are situated in
313
>* • •
1
I
1 1
11
1
- ■■■
:, li
^0i
^TT
M :'
I
.ni
ttiillili
Ml
m
!'i
:l|
'Mi
Till", NKUVOI S SVSTI'IM.
III!" iiiii'li'i Iciinmiilo iif till' N. Mijjtis, >'. >,'lii'.>.(i|ili(iryiii;iMis,
III II I N. inll<l-Mll<lltu^4, ('liit|i. Mill I : (/«) iiiMirnni'Mtlii'i'i'll limlii's
iif wliii'li itrc sjiiihIimI III llic niii'li'i Iciiiiiiiuli'^ n( ilu' N. ves-
lihiili, < 'Imp. .\ 1,1 \' ; (< ) iiciiroiics i iiim'i'II ImkIu-- nl' « Imli iin-
HJI mil I'll ill t III' iiiii'li'i liTinitiitlcN nl' I lie N. Irip'iiiiinis, ( 'liii|i.
\l,\". :l. Ni'lll'ciliii'. (lii> ci'll Itiiijii's III' wliirli nil' sjliijilnl III
till- I'l'ii'lii'lliiMi, ilir iisoii:"' III' wliii'li run riTrlinilwaiil, iiiul
pll>.^jll|y rcprc-i'iil an inilii'i'rl rriilnil ■-riiMii'v riiiiiliii'tiiiii
plllll, ( 'iKIp. \l,\'l. I. ( 'I'lllllll M'llMirN ll\ii||i's |iil-.-.i|iL; llitiml'
llirmi^li till' ri'i'i'liral pi'iliinrli' hihI llir li'i'iiiiiiiilii>ii>- uI' smli
lixoiit's (iM 'I'lii' li'iiiiiiM'iis 111- lllli'l, Chap. MAM; (/>) iIh'
fttsriciiiiis li'ii;;iliiiliiiiilis iiii'il Jali-<. Cliap. XIA'III : (i) lln'
rnniialjn rrliniliiri'* allia, I'liap. NI.IX; («/) irrliiiii IIIhi'n nl'
I III' liiai'liiiiiii ri'iijiiiii'lix iiiii Mini I III' Till Hal inn-- nf llu' ii in 'In is
niliiT. Chap. Ii. ."». Ci'iitiiil si'ii-,.ir> asuiii's pa>>'-iiiy: lliii>iii;li
lln> iiilii'iial capsiili' (I'lirlirupclal priiji'i'liuii iiriiiniii-- uf Ilir
p'lii'ral si'iisory piilli) — (a) Kniliryi>h>Ki<''il syslnn Nn, I ; (/d
i'nilir\i>liij;iial --ysloiii Nn. 'J; (/'\ I'lnliryolnyii'iil sy-lriii N'n. It.
Chap! \.\.
H. Ci'iiliiil nriii'i'iii's of ciiiiiliiit inn paths I'lirrt'spiiiiiliiij; In tin'
I. Ct'iitiiil iii'iirnii
-f I
II' un-
orj;aiis uf spi'rial sen
lalnry I'liiiiiiiitinii path; 'J. Ci'nlr.'il nriirniii's uf llu- olfai'inrv
iiiliii'tiKii path. Cliiip. 1,11 : :t. Ci'iitral n
.ft
('iiiiiliii'tioii path. Chap. 1,111 ; I. Ci'iitiiil iii'iiii'iii's o
aiiiiitnry I'Kiiiliii'tiiin palli, Chap. I.l\'.
II' \ isinl
I' I hi
Srn>i:rriiiN III. Ni'iiimiii's liiri'i'llv roniu'i't ins,' tin' I'rn
tval
nrrvniis svsii'in
\vi
th till' voluntary iiuisi'lcs uf i hi' limly (lower motor iii'iiroiii's),
.\. Tliosr pi'ilainiiii;- to Ilir s|iimil I'oril. Chap. I,\'.
H. 'I'lioso portainiiii; to tlu' rhoniln'iu't'phalon, isthmus, ami
in<'si'iiri'ph.'i'"ii — 1. Thosi'. till' axoiii's of whii'h lirloni; jo till'
N. h
iviioiriossu
.'ii'i'ossoruis
'J. 'I'hosi', till' axolli's of wliirh ln'loiii; to I hi'
;i. Thosi'. lit.' axoiu's of whii'li lu'loin; to t hi'
N. vaj;iis I't ijlossoph.'iry iii.'1'iis : -1. Thosi', llii' axoiii's of \\ liiih
lioloiijl to till' N. farialis; T). 'l'liosi>, tin- iixoni's of wliirh
lii'loiii: to till' N. .'iliijuri'iis : fl. 'I'hosi'. tlu' axoiii's of whii'h
lii'loiiir to till' N. tii:;i'miniis
Tl
lOSI', Ihl' ilXOIll'S o
r whi,
lieloiiij to tho X. troi'hh'aris : S. Thosi', tlu' axoiii's of wliirh
hi'loiiij to till' N. oiiilomotorins, Ch,'i|i. I,\'l.
MUsKiT
ION IV. Xt'uroi
ii's wliiili oiiti'r 'iilo
iiiiiurtion ri'latioii with il
lowi'r motor iii'urom's ami throw thi> lalti'r iiiuli'r llu' inlliu'iiri' of
oihor I'l'ii
Iri's (iiiti'rmi'iliary ami uppor niotor m'iirom>s).
.\. Thosi', I ho axoiii's of whii'h lu'lji to imiki' up I hi' fjisrii'iili
proprii of tho sjiiiial oonl. Chap. lA'II.
H. T
tin' axoiii's of whii'li run in tin- fa
iiliis lonuitmli
nalis iiu'ilialis ami in tin' format io ii'tioiilaris alli.i of th
rhonilii'ni'i'plialoii. Chap. li\'lll.
C. T
lOSl', till'
-11 lioili
I'S 111 Willi
li !iri' sitiiatoil in lln' I'l-n
bolliim, Chap. M.\.
(IK'ul l'IN(i ASH CIIMNINO ToOK'niKU oh' NKWUONKS. ;{|r>
|). 'riiiHc, III!' I'i'll liiiilirs iiT wliich nw siliinti<il in Iho iiichhii-
ri'|iliiiliiti uikI ilii'iii'i'|i|iiiliiii, ('lm|), li\.
M. 'I'linsr, |||(* I'i'll liMijji'i of wllii'll lire sitlllllnl III till' ti'li'll-
i'i'|iliiiliiii ||iiilliiini uml i'liinrMi'r|iliiiliiii) I. 'I'linsi', tlii< uxiiim'h
III' wliirli i'iii'ri's|Miiiil III till' riiNi'ii'iili i'i<i'i'lii'nM|iiiiitlt's or py-
niiiiiilnl Iriirl, ('liii|i. \,\\ : )i. Thiisi', llii> iixhiii'n nf wliicli
run til till' llloliir IIIM'li'i nT Ihr I'lTrlllui ni-I'Vrs, ('lm|i. liXJI ;
U. 'rili)'<i', I lie IIXOIlt'H nf wllirll <'iill'i's|iiil|il In I In- rinlllul I'lMO-
lirni'iirlii ii|iiiiiliil |)iilli, riiii|i. liMII; I. 'riinsi', llii> hxihh's
of wllii'll riirri'M|iiiiii| In llir li'iii|Miriii t'i'rrlii'ni'iii'lii'ii|iunlii|
|illlll : ''t. 'I'lmsr, I III- iixnili's or wllii'll rniiiiril. Ilir Inliiis nrci-
pilaliM Willi III!' inirii'i jjovrrniiij; lln' iiiovi'mciils nf I hr i-yi-M;
li. 'I'linsi', till' ilxnili'S nf wllii'll rnlitii'i'l I ||i' rllitli'liri'|illlllnn
Willi till' InWCr niolnr IH-lllnlli's, ('iiii|i. I,,\l\'.
Si ' IIS Ki Tins \'. i'l'iiji'i'liiili llclirnlii'H, collllllissiiriil lii'lll'olics, illlii iismii'IiiI if ill
IHMirolirs nf till- li'li'liri'|illllliill.
A. I'rnjri'l inn iii'iirniii"-, ( 'Imp. L.W.
H. ('nllllllissi:'"' iii'iilniii'H : 1. 'riinsi', liic llirilllljlllni llXniii'snf
wllirll I'nrri'spninl In llii' tliiic'M nf llii' I'lirpiis I'lillnsir ; 'J.
'I'iinsi-, I III' llinlllllilli'il llMiMi's nf wllii'll rnl'i'i'spnnil |n |||(>
('niiiMiis.Hiiriv luilrrior coiTliri ; it. 'I'lmsi', Ihr iiiiKiiiiiult'il
llXnIII'S nf wllii'll I'nlTl'SpnlKJIn Mil' lillll'siif | ||i IIIIMlMSIiril
ilippni'HIIlpi, CilMp. li.W'i.
('. Assni-illlioll llOlll'OllfS: I. 'riliKc with slimt lixmii's; 'i, 'i'lin-;i<
wit ll Inn;; nxniirs, < 'hap. Ij.W'II: -S. Iinriili/.iil inn nf iissnriii-
tinli lii'lll'niii'.s ill till' crlrldlil mitc'X. l'"li'i'l|si;;'s linrt rilll! of
"iiasociiitioii ci'iitn's," Chnii. li.WIII.
(ii.\i"ri:ii ,\.\vi.
[N'l'UdlUCI'OllV
Mi'lhnils nf iji'script inn — ('lussiticillinn tn ln' rnjlnwi'ii Al'i'lliti'l'tilllics nf tll«
iicrvniis sysli'iii— NiMirmu' systrms — Cnniliii'linn put lis,
]
Onm would like lo he iihic to dcHCirilic tlic struct urc of tlic
liiiiniin nervous syslciii accofdiiif^ t:o tlic iirniii^^cuicnt of tlic
iiciifoucs iiiidcrlyiiifjf the Viirioiis fiiiietioiiid nervous pnxtc^sses.
rnfortuiiutcly, the limited knowlcdiji^ we haw at present siif-
lices only for a I»e;,'iniiin<f of siudi a description. We Inivc
i,Miiicd, it is true, important clews concerninjf the individuality
of mechanisms, the successive complii^ation of nervous plic-
nomemi, and their striK^tural husis from comparative anatomy
. t'
ti
31(5
TIIK NKUVOrs SYSTHM.
and from studies in oiitojrciiy. 'IMiiis, Kdiiiffcr* in tlic last
edition of his text-book has given us for tiie first tinu' a vii'w
of tlu' suceessivo increase in eouiplexity ehanu^teri/inf^ tiio
nervous systeins beh)n<;in<f to a larj^e series of aninuils, and tiie
l)hysi()loijrieal studies of Jae(iues Loeh, ,1. SteiiU'r, and A. Ik'tiu^
jjfive us a {flinipse of wluit we can hope from tlu' study of the
functions in h)\ver forms. Kleehsifj's method permits us also
to form some idea of the nuudumisms underlyin<^ the simplest
lU'rve functions in human hi'ings and those coiu'crned in the
(H'rfcrmance of the more complex ones u\) to at least the fifth
month of extrauterine life. Hut none of these nu'thods fur-
nishes us with more than a ./v^ginning on the lines indicati'd.
In the descri[)ti()n to bo given here of the grouping of the
lu'urones no attempt will be made to describe the groups ac-
cording to the se(|ueTU'e met with in the developnuMit of func-
tion, but instead, inasmuch as for practical purposes this seems
at the moment to be more important, some of the main grou})s
of lU'urones with wliich we are fairly well accpuiinted aiul of the
fuiu'tions of which we have a n^latively extended knowledge,
especially as they appear in the lu'w-born babe and in the adult,
will be dealt with.
The central cercbros])inal nervous system is ordinarily de-
scribed as lu'ing connected with the other organs of the body
aiul with the external world by nuvms of nerves. These lu'rves
contain fibres of one or both of two sorts, atferent or centripe-
tal, and efferent or centrifugal. By nu'ans of the former the
neurones within the central system are cajjable of being influ-
enced from without; through the latter they exert an inlluence
upon other parts of tlu> body. i\) Ixirrow an illustration from
von Lenhossck, the i)eripheral nerves care for the "import"
and " export " relations of the central nervous system, while
the neurones inside look after " honu' " relations. In the fol-
lowing at'C(»unt, therefore, it will be nec^^ssary to consider tin*
structural relations of the neuroiu's which coniu'ct the sense
organs of the body with the central nervous system (imdud-
ing the afTerent nerves), of those connecting the central nerv-
ous system with tlu' muscles of the body (including the etTerent
I
* Edinpor, Tj. Vorlt'suiifron tiobcr dcii Rau dcr norvoscii rotitnilortrinii'
lies Monschcn iiiid dor Tliit-n- fiir Acrzle mid Studirciide. 5. Aull., Lcijiz.^
1H!»H. :t!»H p|).. Hvo.
(IHoriMNCJ AN'I) (MIAININ(i TodKTIIKR OF NKIKON'KS. HI7
m]^^fi
nerves), im<l of those of the eoHeetioiis of neiintiies ijisiih' the
eeiitnil nervoius systi'iii. Tlie dilTereiit {j^roups m;iy l)e coii-
veiiieiitly discussed iiii(h'r tlie foUowiii;^ headiiij^s:
I. Neurones eoiiiieetitifi tlie sense or^Miis of tlie hodywith
I lie eentnil nervous system (iieripheral eentripetiil neurones;
Heiisory neurones of the first order; sensory proloneiirones).
Chi.ps^ WVIl to X.WVIII.
II. Neurones within the central nervous i-ystein conneetiniif
tlie end-stations of the axones of the perij.hiral centripetal neu-
rones with other portions of the central nervous system, and
neurones wiiicli in t urn connect the end-stations of the latter
with still hi^liei' portions of the central system (sensory neii-
I'oiiesof the second order and of hij^her orders). Chaps. \ X X I X
to LiV.
ill. Neurones connecting' the central nervous system with
tlu' voluntary muscles of the hody (lower motor neurones).
Chaps. i>\' and LN' 1.
1\'. .Neurones within the central nei'voiis system which enter
into conduction relation with the lower motor neurones and
tiirow the latter under the iiithienco of other centres. Neu-
rones eonnectinjj the pallium, cerchcllum, etc., with the lower
motor iH'uroncs. Chaps. IjVII to LAIX'.
\. Project ion, commissural, and association neurones of the
telencephalon. Chaps. LX\' to liXN'lil.
.\n idea of the t<'ctonics or arciiitecturo of tlie nervous .sys-
tem, coMsiderinn' the neurones as the architectural units, can
he j;ain<'d only when we foriii spatial conci'ptions of thedistri-
hution of the various neurones and their processes in the cen-
tral and peripheral nervi' organs. Such spatial conceptions are
ohtainahle only hy comhininfi; in the mind the results of a
whole scries of studies — emhryolo;4ical, histolouical, physio-
logical, antl pathological. A careful study of the topoj^raph-
ical relations in faultless sets of soriiil sections throuf^h various
dejifeneratcd nervous systems, or through the fo'tal (ientral
organs at various stages in the process of myeliuization, together
with the study of (Jolgi preparations, permits one to make
mental fusions of the single. [)ictures, and so to ohtain an idea
of the distrihution in space of the various lihre hundles, and
the cells of which they represent the niedullated axones. .V
much more aeeurate method is tl':it of graphic reconstruction
from serial sections {W . His), 01 plasties reconstruction hy
^^ #•..»•
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318
THE NERVOUS SYSTEM.
means of wax plates (G. Born). The advantages of the latter
method are illustrated in the model of the rhomheiicephalon
and mesencephalon constructed by Miss Florence Sabin, to
which references are occasionally made in the following chap-
ters. If he has not obtained " ideas in three dimensions " of
the groups of neurones and their interrelations inside the cen-
tral nervous organs, the student will find himself entirely at
sea when he attempts the explanation of the results of patho-
logical lesions.
The term " system " is employed often by neurological
writers, and unfortunately not always in the same way. It
would seem desirable,* in accordance with recent German
writers, to limit the use of the term " neurone system " to an
aggregate of homologous inaxones, and to restrict the use of
the term " fibre system " to a group of medullated axones of
homologous origin and homologous distribution (as regards
their collaterals, subdivisions, and terminals). Thus, for exam-
ple, the neurones, the cell bodies of which are situated in the
spinal ganglia, the central axones of which enter the dorsal
luniculi of the spinal cord and terminate in its gray matter or
in the nuclei of the medulla oblongata, together represent a
great " system " of peripheral spinal centripetal neurones.
This system is in turn divisible into sii/j-si/sfeins — (I) on the
ground of myelinizution ; and {'2) according to the particular
nuclei in which a given set of fibres terminate. Tlje fil)n's of
the pyramidal tract represent a " fibre system," since ( 1 ) they
are the axones of homologous cells in the cerebral cortex, and
(2) they terminate in homologous regions in the spinal cord.
Topographical study teaches that there may be a " mixing
of systems" in given areas of a cross section. A given topical
area in a microscopic section seldom represents an entirely
pure " fibre system." It is legitimate, hoAvever, in topograph-
ical descriptions, to give names <) fortiori to th? vjirious areas.
Thus we speak of the " area of tiie lateral pyramidal tract " in
a cross section of the spinal cord, although we know that in
tliis area a few fibres other than those of the pyramidal tract
* Cf. Tschormiik, A. rdicr den ci'titralcn Vcrlaiif dcr nufstcifroiulon
niiitorstnuiglialuicii und dcrpii Bezichiinfjon zii dcii Hiilincii iiii Vordcr-
soitonstratig. Anli. f. Atiat. ii. I'hvsiol., Aiiat. Abtli.. \aA\y/.. (1H98). S.
2!) 1-400.
UK()UPIN(J AND CHAINING TOGETHER OP NEURONES. 319
exist ; and again we call a certain bundle in the dorso-latiTal
periphery of the cord the fasciculus cerebellospinalis, or the
dorso-lateral spino-cerebellar system, though we have good evi-
dence that the fibres of this fasciculus are mixed, in places at
least, with fibres not homologous with the spino-cerebellar fibres.
A chain or series of neurone systems, constituting a function-
jil unit of a higher order, may be designated a " conduction
path " — the (Jermans call it a Lcitiingxbahn.* Thus the several
" systems " following upon one another in a given " conduction
path " may be spoken of as primary systems, secondary systems,
tertiary systems, etc. In the general centripetal conduction
path from the muscles to the cerebral cortex the peripheral
centripetal neurones corresponding to the spinal ganglion cells
represent a " primary system " ; the neurones of the next liigher
order (whose perikaryons and dendrites are in the nucleus fu-
nicrli ciineati (or nucleus funiculi gracilis) and whose axones
run as internal arcuate fibres across the raphe into the opposite
interolivary layer, and on through the medial lemniscus to ter-
minate in the ventro-lateral part of tlie thidamus) represent a
" secondary system " ; while the neurones connecting the ventro-
lateral part of tlie thalamus with the somaesthetic area of the
cerebral cortex represent a tertiary system. This sensory " con-
duction path" would consist, then, of three superimposed sets
of " neurone systems." As we sliall see, in the " aiferent " or
"centripetal" conduction paths the perikaryons and dendrites
of a given "neurone system " are, as a rule, situated l)elow and
the axones ascend toward the perikaryons and dendrites of the
next neurone system. On the other hand, in tlie " efferent "
or "centrifugal" conduction paths the perikaryons and den-
drites of a given neurone system are situated, as a rule, alxnr^
and the axones descrni/ toward the perikaryons and dendrites
of the neurone system of the next order. To use a nomencla-
ture suggested by Tscherniak, the efferent conduction patli is
composed of " distal-axone " systems, and the afferent conducticm
path of " central-axone " systems. The " distal-axone " systems
are in the main motor or reflex, the " central-axone " systems,
in tlie main, sensory.
*rf. Held, IT. Arcli. f. Anat. u Physiol.. .Anah Abtli.. Lcipz. (1893).
S. 4;?(), Also till- nmiierous imblicutioiis of I'mil Fleelisig and ot VV. vou
Hpohtercw.
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320
TlIK NERVOUS SYSTEM,
III a given conduction patli, composed of aevoral superim-
posed or subimposed neurone systems, tlie primary, secondary,
and otlier systems need not necessarily contain tlie same total
number ■^f neurones ; indeed, as we have seen already, and shall
see furi'ier on, a single neurone of one system is often, by virtue
of a number of end-rauiilications, able to enter into conduction
relations with a lunnber of neurones in a neurone system of tlie
next higher order (e. g., terminals of N. trigeminus in the sub-
stantia gelatinosa, terminals of tractus opticus in the colliculus
superior) ; in other instances, on the contrary, the terminids of
a large nund)er of axones-of one neurone system may be so
arranged that tiiey can influence only a snudler numl'cr of
neurones of a neurone system of the next order (e.g., Nn.
olfactorii, terminating in the olfactory ghmieruli). in t'.<' one
case there is a "■ multiplication of elements " in the direction
of the conducting path, in the other a "reduction cf
elements." *
To a description of the various neurone systems, at least
those that are best known, wc nuiy now conveniently proceed.
* For further interesting considerations of a similar nature witli regard
to neurone systems and eonductiim piitlis. especially with refciTiice to tlie
(lircn/i'Hcc and ciiiiHiieiicc of paths, the reader may turn with advantage to
the article of 'rsehenuak above cited.
SUBSECTION I.
Neurones Connecting the Sense Organs of the Body
with the Central Nervous System (Peripheral
Centripetal Neurones ; Sensory Neurones of the
First Order; Sensory Protoneurones).
CIIAl'TER XXVII.
0\ TIIK OLASSIKICATIOX OF SKNSOKY I.MPKKSSrOVS AND THE
KKLATION' OV TUK CKXTKl I'KTAL MU" HUNKS TO TU K SK(}-
MKNTATIOX OF TlIK BODY.
Neurones t'olleetiiij; Ijoilily impressions — Nouroni's collecting impressions
from the external world — Kxternaliziition of im|)ressions — The neural
sej^ment or ucurolouic — N'n. spinulcs — Uiidix vcntralis — Riiilix dorsalis
— Ganjjlion spinalc — I'criphenil nerves — Rami communicantes, ete. —
Plexus eervico-brachialis — Plexus lumbo-sacralis — Cutaneous distribu-
tion of peripheral sensory nerves — Cutaneous distriliutioii of dorsal root
fibres — Experimental studies in animals — Overlapping— Clinical studies
on human beings — Surface areas of tiie topographical aiuit(jmists.
Thk peripheral centripetal neurones are those through
which the central nervous system is affected, (rr) by clianges
taking phice in the body itself (outside the central nervous
system and organs of special sense), and (/») ])y ])hysical and
chemical influences exerted from the environment of the in-
dividual.* This classification of sensory neurones conforms
to the custom of dividing the impulses which pass into the
central nervous system into (X) impressions which (M)ncern the
body itself, and (B) impressions which concern the external
* In this connection it must not be forgotten that the neurones within
the nerve centres can be and often are very significantly alTected by infiu-
ences de|)endont upon alterations in the blood aiul lymph. It wo\ild be a
grave error to assinne that all the ph(Miomemi in the central neurones are
dependent upon reactions called forth by impulses coining in through the
peripheral centripetal fibres. The respiratory mechanism, for example, is
largely of a chemical character. This, however, is so obvious when one's
attention is directed toward it that further discussion here is unnecessary.
-22 321
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822
THE NERVOL'S SYSTEM.
world, the former iiuliulijij; wliiit lius onliiiiirily been known as
"■ <'oiniii()n sensation,''' the lat tcr cnibracin^ the "• special senses."
'J'iie tendency of tiie mind is to refer the sensations which may
result in consciousness from the former sot of impulses to
ohiinges in the body itself, and to project those whi(di result
fr(»m tlie latter set of impulses into the external world ; that is
to say, while the fornu'r are, as a rule, not " ol)jectivisable," or
" externalizable,"' the latter are always or nearly always " ob-
jeetivisable." In the latter set of impressions an element of
externality seems to be iidierent.
Such a distinction, while convenient for purposes of descrip-
tion, is not wholly free from objection. In the skin, for exam|)k',
one meets with a sensory surface which concerns not only the
body itself, but also the external world. And even impressions
brouiflit into the nervous system thron<fh the mnscle sense are
])robal)ly, to a certain extent, objectivisable. For the sake of
convenience, however, and witii this preliminary (jualitication,
the neurones may be considered under these lieadings, the first
group (a) bringing impulses into the nerve centres from the
skin, mucous nu'nd)raiies, muscles, semicircular canals, bones,
tendons, joints, sexual organs, and internal viscera ; the second
grou[> (/*) bringing impressions into the central nervous system
from the organs of special sense ; namely, from (1) the gus-
tatory organs ; (2) the olfactory organs ; (;5) the visual organs ;
(4) the auditory organs.
The relations of the sensorx nerve to the so-called neuratonn'
or neural xajmcnt are shown in the accompanying figure (Fig.
185). If the student grasp clearly the idea of the neural segment
(cf. Cha])ter Will) he will have much less difticulty in under-
standing the archite(!ture of the nervous system in general.
In the illustration the niotur rcntrtd vnol (radix ventralis) is
seen coming out of the ventro-lateral surface of the spimil cord,
being formed by the union of a numl)er of fila radicularia. It
turns dorsal ward where it is joined by the dursal sensor ji roof
{'.]) or radix dorsalis, in tlie course of which is seen a nodular
swelling, the (/ini(//ioH sjtiitir/e (4). The ventral root forms no
definite union with the dorsal root, but simply lies beside it, the
combined roots forming the roininoii or ini.red iterre sfeiii (5).
Tins common stem of a s])inal nerve divides into two main
trunks, the rtn/nis tlorsitlis ((J), which runs dorsalward to su])ply
the nuLsculature and skin of the back, and a ramus ventralis (T).
Ill
(iU()UI'IX(t AND ('HA1\IX(} 'nxSETIIPMl (>F N'KUHONES. ;52;3
wliicli turns vi'iitralwanl into tlio ])iiriott's to supply the niuscu-
liiturc and skin of this rc^^ion, includinjjf the niuscuhiture aiul
skin of the I'xtreinitios. This ventral ramus in ty])ical instances
gives otl" {(i) a lateral branch, the so-called ramus culaneus
Fl<i. IS.'). T'ross scctiiin 1)1' till' central iiiul pcriiilicral ncvvdiis systt'iu of ii iiiati,
illiistratiuu Ilif neural sej;iiieiit. ( After. V. Kauber. Lelirlmeli dcr Aiiatoiiiie
ties Meiiselieii, V. Aiilt, Leiliz.. ISltS. M. ii. S. •,>»).->. Fij;. SXi. ' I. tissiiia
iiieiliaiia veiilralis id' {\w Npiiial coril ; /', sulcus iiiediaiuis doi'silis ; .^ radix
veiitralis i motor i : ..'. radix dorsilis > sensory ' ; .J, jjaiifilioii spinale : -7, n<'rvus
spinalis iconiuupn trunk i ; (i. ranuis tliirs;ilis : ,', ranuis ventralis ; ,s. ramus
commnnicaus : ;/. ranuis ni<nin;ieus ; /". KauKlion synipatliicum ; //. ramus
cnlaneus lateralis ; /,'. dorsil lindi. /..', ventral linili ol' // .- /(. ranuis cutaueus
ventralis dividiuu into a medial liinl) /.I and a lati'ial liml) /'/. Tlie cross sec-
tion of the spinal cord shows the Il-shaped snhstantia urisea with t'le canalis
centralis in the coinmissiira jrrisea. Aliout the substantia j^riscu lies the white
mantle I'ormed hy the snhstantia alha.
lateralis (11) (which in turn divides into a dorsal (l"i) and a
ventral (13) linih), and [li) a more ventral branch, the ramus
eutaneus ventnilis (14), which (dividing into a medial (l/i) and
a hiteral (Ki) limb) innervates the skin on the ventral surface
I /*|||li|
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5i!i|ift|ii;i|
324
THH NKllVOUS SVSTKM.
»»f the body. The other hrjuu'lu's of th(> rami vcntnilos iiiiicr-
Viitt> tilt' wliolf of the vt'iitral iiuisculiiturc, iiu'ludiiig the iiius-
ck's of thf superior ami inferior extreiuitiivs.
Via. lS)i. — Plexus cfrvicD-linicliiMlis. i At'lor V. Kislcr. rrniii Rmilicr's tcxf-book.'l
Vilitval view. /i. ncrviis liyiiiitilnssiis ; tlli, riiinlls ilisci'iiilciis liypo^jliissi,
\ i'll I ill 1 * n »> . »», I n I * n.-» 11^* 1" 'ii M '^^iir. , II If , I )i III ii.^ 1 II .->» I nm n.-« ii^v |i> '^ i< '--.-• i,
wliicli, aloni: with dr. tlic raiinis (hsi'cnilciis ciTvicalis. tonus tlio ausi liyim-
tiliissi : (iiii, N. occiiiitalis miiuir : mi, N. aiiiiiiilaris nia^'iiiis ; sir. N. cutaiH'iis
colli: (I, to N. actcssorins ; spr. Nil. siiiiraclaviiulaivs : p.S. iiliniiicus ; ils.
N. (loi-siilis scaimliv ; n/is N. siiimisi aimlaris : nn, Nn. suliscaiiiilarcs ; nc, N.
sulH'laviiis : n.r. N. axillaris: <•(!, N. tlioraio-lirailiialis : A", N. nulialis: we.
N, niUMiilo-tiitaiiciis : .1/, N. iiitMliaiuis : In. Nil. tlioracalcs vnitrales : II, N.
thorai'alis latcnilis ; l\ N.uliiaris: cm, I{. i iitancus iiitilialis ; ci, N.i'UtaiK'Us
iiit'dialis : ill, N. intorcosto-bracliialis.
In addition to the main division of the mixed or coinnioii
nerve stem into a ramus ventralis and a ramus dorsalis, two
(IHori'INMi AND ("HAININCJ TOOl'VI'IlKIt OK NKl'IMNKS. ,'^25
other rami arc j^ivcii oil" from this mixed trunk, namely, the
runnis rinnininiinnis (H), containiiif? iH>th sensory and motor
fibres (h'stinetl for the viscera and hiood-vessels hy way of tiie
sympathetic nervous system (10), and a riinins i/ii')ii/i;/riis (U),
wliieh runs hael< throu;;!) the f(»ramen intervertehrale to enter
tlie vertebral canal, there to break up into fibres, which are dis-
tributed to the spinal cord, its sheaths, and the walls of the
vertebral canal.
it would be a mistake, iiowever, to leave the impression
that in each /wn'/t/imtl iirrir there are sensory and niotor fibres
correspond in<i; only to one common stem derived from a sinj^le
neural segment. While this would be true, or nearly true, for
the thoracic rej^ion, it would not hold for the cervical, lumbar,
and sacral regions. In these regions the raiin' rcnlnilcx form
anastomoses and plexit'orm unions, so that the derivatives of
neighboring neural segments become incorporated in (u)mmon
bundles, it is customary to descril)e two large nerve plexuses :
a supi'rior — the so-(^alled pic.nis cm'ic(i-/)r<ic/tiiili.s ; and an in-
ferior — the so-called p/cxiiK hiniho-sitrralis.
The plc.nis rcrriio-hrachicdis (l''ig. IcSCi) arises from the anas-
tomoses formed by the rami ventrales of the cervical and first
two thoracic nerves. It is subdivided into the (1) plc.nis rcr-
I'ifdlis and {i) tlu' pJr.nts /tnir/iia/is, the latter being further
subdivided into {(() a purx siiprarlacicularix and (//) a pars
iiifnir/(in'rii/aris.
The ph'.nis litinh(i-s((cr(ilis (Fig. 187) can be subdividi'd into
(1) the pir.nis /iiiii/i(//is,{'i) the plrxiis sdi-rah's, iuu\ {'.)) the ph.riis
pN(/i'ii(/(i-f(iii(/(t/is, the latter being further subdivisible into (a)
the ph'.iKs pinh'iidiis and {h) the plcrux cocfi/f/fiis. The plexus
lumbalis is c(»niposed «)f the ventral rami derived from the
mixed stems of the four up])er Nn. hnnbales, while the ])lexus
sacralis has its origin in the ventral rami, derived from the fifth
N. lumbalis and the first and second Nn. sacrales.
The plexus pudendus is formed by the ventral rami derived
from the mixed stems of the third and fourth Nn. sacrales, the
plexus coccygeus from the ventral rami of the fifth \. sacralis
and the first N. coccygeus.
As a result of the anatomical conditions just referred to,
it must be obvious that the clinical symptoms dependent upon
lesions of the peripheral sensory neurones will vary widely ac-
cording to the situation of the lesion.
•if
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320
THE NERVOUS SYSTEM.
Tliiis, the flistribution of the (listurbancos of ciitinicoiis
sensibility will bo very (litTereiit in u case in which a nerve is
■ibxii
Fig. 187.— Plexus Iinnliosiicralis, iiiflii(liii« the plexus luiiilmlis. Die plexus
Siieralis. and tlie plexus pudeiidus. Ventral aspeet. (After 1'. Hisler, taken
fnmi IJaulxT's Lelirl)n<li der Analoniie des M<iis( lieu, i W, ramus eutaneus
lateralis (if the N. suhcostalis: ill. N. ilinhypDnastrieus ; ri, itsraui isiliacus; ii,
N. ilioiuKniualis; (//. Nerve lor (luadratiis luinlioruni ; xi\ N. speruiatieus ex-
ternus; /;. N. Innihoiufiuinalis ; /*, ramus uuiseiilaris to M. psoas; c/. N.
eutaneus fenniris lateralis; (. ramus inuscularis to M. iliaens: (>, ramus mns-
eularis to M. iliopsoas: ('i\ N. I'emoralis ; mi. N. olilnratorius aecessorius ; <>,
N. ol)turat<irius: i;.-'. N. fjlnta'us superior: pi. ninuis nuiseularis to M. jiiri-
lormis; /V, \. pcriiniens; (/(. N.KliitaMis inferior; 7V. N. tibialis; ,/i. rami nms-
eulares to \\u\. Ilexores e'ruris ; (/, ranuis muscularis to M. M"'"''/'''"^ '''"'""'''^
and M. jrenu'llus inferior ; ai. ramus nuiseularis to M. obturator interniis anil
M. gemellus superior; rp. N. eutaneus femoiis posterior; ciii. N. <'Ut. eluii.
inf. niedialis i N. perforans li^'. tuberoso-saerum • ; jiii. N. pudendiis ; li. N.
lia'inorrhoidalisext. ; /, ramus museiilaris to M. levator ani ; c, ramus nui.seii-
laris to M. eoceyKous; (/, b, Nu. auoeoi'cygei.
1 ■■!
i'l
OKOUIMNO AND rilAlNIXCi T<h;I:TIIK|{ of NKl'UONKS. 327
injured near tlic periphery, from tlmt to l)e riiiide out in a
ease in wliieh one of the strands of a nerve plexus is involved,
imd the distrihiition in hoth tlu'se instances will a^'uin l>e
(|uite diU'erent from tiiat met with in lesions of a dorsal root
of a spinal nerve. Finally, lesions of the intramedullary
continuations of the dorsal roots, owinj^ to deviations in the
paths followed hy individual l)undles arisin}^ from a f,Mven
root, will yield disturbances in sensation (|uite dilTerent in
distrihution, aiul probably also in the (|ualities of sensation
interfered Avith, from those met with in any extramedullary
lesion.
The cutaneous distribution of the j)eripheral sensory nerves
has been tolerably carefully worked out by means of (1) dis-
I'lii. 1S8. Tlic ureas siipiilicd l)y tlic cutaneous nerves of the head. (After F.
Merkel, tak<'n from Kauber's text-liook. )
sections on the dead, {'i) experiments on living animals, and
(:5) clinical observations on diseased human bein<;s followed by
careful post-mortem examination. In I^'igs. 1<S<S-1!K) the main
■M
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328
TFIK NKin'ors SYSTKM.
rcKults (if these stii'lies are illiiHtrated. For further details tlic
viihmbh' athis of hasse* may he consulted. Now that we
•fO.
am
M7»«^l
.>* n
11 .\ s
ivu
l'"l(i. IWI. Anns sni)iili((l by the ciitaiicinis nerves of the ni)i)er extremity.
(AI'terA. IviinlHr. I.ilirlilieli dtr Aliiitoliiie des Melisclieii, \' . Ailll., Jicip/..,
IHitM. 15(1. ii, S. {S'M. Ki^. rvtlt. > A, volar siirl'aie ; I',, dorsal siirfaee. kc. Nii,
siipracliivieiilares : iix. \. axillaris ; cm. N. ciitimeiis hracliii iiiedialis ; c./hci/,
N. cntaiieiis aiitilinicliii inedialis; c.iiifd' . area of upper arm supi)lie<l l)y t'lire-
Koiiit; nerve ; (•/, N'. eiitaneiis iinliliracliii liileralis. u lirancli nt' tlie N. miisciild-
eutanens; »•'. N'. cntaneiis hracliii iiipsleriui- (liraneli of N. nidialis); r'. N.
eutaneiis antihracliii dipi-salis ' lirancli id' N. radialis) : i-^. branch of N, radialis
(in the h;ick of the liaixl : ". N. iilnaris i ramns dorsalis niainis and rannis
volaris mantis) in the hand : n' . ramns ciitaneiis palmaris id' N. iiliiaris: m.
N. iiieilianns in the hand : m' . its ramus palmaris.
* Hassc, C. Iland-Atlas der sensiblen utul motorischpii (Jehit'te des Ilirn-
iiiid Kiickcmnarksnervon (3G Tnfeln). Ztiiii (Jebrauch fiir [iractische Aer/te
mill Stiidirciidi'. Wii'shaden (IHi)")), Hvo.
GKOUI'ING AND CIIAININC} TOGKTIIKK OF NKUKONKS. S29
iK
'U.
d.i.
v.s. /
y
^
c.cr.
n '
le.i
um
su-
\J).S.
K:
B
nUfiriiis ;
IHistcriiPi'
siiiicrlicia
Nil. (lifjiti
halliicis 1
lihiiitai'is
Fid. UK). — Tlic areas iif the skin siiji-
plitcl liy the ciilaiirous nerves nC
tlie l<i\ver e.xlreniity. .\, ventral
surlaee ; 15, (liirsil surlaee. .Mter ^\
A. Kaiilier, I>elirl)iulitler.\natiiniie
<les Mensehen, \'. .\iill.. I.eip/..,
1H<)H. 15(1. ii,S. (i;u, KIk. ")■)!'. ) In H
tile (liini.iin rcirtlie dursil liranelies
of liie plexns liinilMi-sairalis is out-
lined on the iHisleriorsurfaee of She \\, lS\li}\
hip, the liranelies (/. /. Iieinn (lor.sil
liranelies of the Nil. Illinliales ' .\n.
elnniiiin sii|ieriores) ; </. .s.. dorsil
liranelies of the Nil. Siieniles '.Nii.
elnniuni inferiores' : r. .v. , area sup-
plied liy the N. perforaiis lit;, tiiher-
oso-saeruni ; //(.. N. iliohyponastri-
eiis; (;, area of distriliution of the Hip^-'
N. ilio-inKuinalis and N. speriiiati- i|.
(•us externns ; './., N. lunilio-inf,'ui-
/ nalis; c./., N. eiitaneiis fenioris
■pii, lateralis; (•.<•(•., rami eiitanei ante-
riores of N. feiiioralis; o, N. ohtu-
('./>.. X. eutaneiis fenioris posterior; .w., N. sapheiius ; \i.r., lateral, yt.m.,
liraneh of N. |ieroiia'iis to the lef; ; .vH., N. siinilis; /)..>;.. N. peroiui-US
lis ( N. eutaneiis dorsilis niedialis et N. eiilaneus dorsalis inleriiiediiis I't
ales dorsales pedis) ; >)./(.. N. peroineus profundus • Nil. dinitales dorsali's-
atenilis et difiiti seemidi iiie<lialisi ; m.. N. ptaiitjiris niedialis; /., N.
lati'ialis.
'f ^
1
%
■w
/
m.
i
1
. <'
i
1 1
[/
'
i
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1
t
i
330
TlIK NERVOUS SYSTEM.
know from the studios of Mlix, * (loldscheider, f von Frcy, J
jiiid V. Ik'iiri that at least four qualities of sensation — cold,
warmth, touch, and pain — are mediated by the skin and appar-
ently by means of specdtie sense organs, it is important that
the surface of tiie body be reworked to determine whether or
not the peripheral areas are identical for tiie diU'erent sense
(jualities. As we shall see in a few moments, the segmental
areas at least a})2)ear to be somewhat different for the dilfereiit
•lualities of cutaneous sensation.
The study of the sensory areas of the surface corresj)on<iing
to the dorsal roots of the spinal nerves, in addition to its high
clinical importaiu'c, has excited so much interest and has been
prosecuted in so nniny ingenious ways that a brief syno})sis
of the researches and a statement of the present status of
knowledge and belief in this connection may not be out of
place.
As early as 1S40 Eckhard** stated as a result of a few
experiments that the field of skin to which a sensory root
goes is not exactly that whicdi overlies the muscles which are
su})i)lied by the corresponding motor root. This research was
soon followed by sniother from the same laboratory, this time
from Peyer.|| This investigator sectioned all mixed nerve
stems except the one which he was studying, and then a]>-
})lied mechanical and thernnd stimuli to the skin. He came
to the conclusion that in the skin of the fore-limb the fields
of the individual spinal nerve roots more or less overlap one
a ..
I,
* IMix, M. Expi'iiinentfllo Heitrage ziir liosiiiijj dor Fnige u('l)er (iie
speeifischo Knorjjie der Ilaatnorvi'ii. Ztsclir. f. Hidl., Bd. xx (1H84). S. 141.
f (idldschcidcr, A Oesainineltc Abliaiidliingcii iichordie Physiologic dos
Muskelsiniips. Leipz. (1898).
t von Frey, M. Beitriigp zur Sinnpsphysiologio dor Tliiiit, i, ii. iii, iv,
Fieipz. (18i)4-"97). Aus den Hcrichirn dcr matli.-phys. CI. d. 1<. Sachs.
Gcsciisth. dor Wisscnsch., .Tidy 2 and Doc. .1. 1894, ^Farch 4, lH9r). and Aug. 2,
1M97. .Mso, Fntcrsiichiuigcn uchcr die Sinnosfunctionfii dcr ni(>ns( Idichcn
Hunt. Erste Ahhandliuig. I)ruci<(Mnp(indiing un<i Schinc-z. AMiaiidl. il.
inatii.-[)hys. ("1. dor k. Sachs. Goselisch. d. Wissciiscli., boipz.. Hd. xxiii
<189()). No. iii, S. 17r)-2(](!.
* Eci<hard. ('. Teller Ilofloxho'vcgiiiigcn (icr vior lotzton Xorvonpaare dos
Frosches. Ztsohr. f. rat. XM., Hoiuelb., Rd. vii (1849). S. 281-:51(>.
I Poyor, .T. I'ohor die poripherisclion Fndigiingen (h>r inotorisclien iind
SL'nsil)ien l-'asorn dor in den I'loxiis hrachiidis des Kaniiioiioiis oiiitrotondon
Nervenwurzehi. Ztschr. f. rat. Med., Ileidolb., 2 li., Bd. iv (1854), S. 52-77.
(illOUlMNG AND CHAINING T()GI<:TI1KH OF XEL'HOXKS. liSl
another. lie iH'licved, liowcvor, that the territorv innervated
hy a sensory «h)rsal root corresponds approximately to the skin
Avliich covers the muscles innervated hy the corresponding
motor ventral root.
The adnurahle researches of Krause* show how much can
l)e done hy simple dissection and dissociation. Krause also
used the so-called reflex method and followed hesides the
degeneration of nerve fibres after section of the nerves. His
studies are of great importance in the history of localization,
and must be carefully considered by every one investigating in
this field, llis conclusions regarding the iiftii, sixth, seventh,
and ei hth cervical roots in the main still hold.
A very important contribution to Icnowledge is to be found
in the research of Tiirck,f who worked out in detail the areas
',th
thnrnt'ir
.ST. ''son/
skin field.
jiiiiimimuiiiiiiiiniimiii
,\\\\\\\\\\\\\^^\\\\\\\\\\\\s\\\\\t^
llimdcic.
r.th
thoracic.
Vui. l!tl. DiaKnini of the position of tlic nipiilc in tlic sensory skin flol.ls of tlic
nil. M. iin'l 5111 'loracic s]iiniii roots. Tlic ovciliippinf; of the ciitiincoiis
areas is represented, i .\fter (;. S. Slierrinjiton. I'iiil. Tr., Lond.. 15.. IsilH,
vol. elxxxiv. ISltt, p. *:{*.)
for the spinal nerves in the dog from the level of the fourth
cervical to that of the fourth sacM-al. His results are very
nearly in accord with those of the more recent studies, and it is
rather curious that they liave not attracted the attention of
4iiuitomists in general. This appears to be due in hirge part,
* Krause, W. l^eitrU^e zur systeniatisclien Xenrolnijie des inensclilielien
Arnu's. Areli. f. .\nat.. I'liysjol. u. wisseiisrh. Med., I.eipz. (1H()4|, S. ;!4!)-
J{.')7. — npitniLrc zur Neur<iloi,ne dor olieren I''xtreinitiit 4 , Leipz. u. Ileidelli,
(ISf).')). — Die Analoinie des ICaiiinclien, in lopnjrrapliisulit'r und openitiver
Iviicdvsie.ht heMrlieilet. 2. Anil., Leipz. ( 1«M4), Hvo.
f 'I'iirek. Ij. Vorliiufiijc Kpfjehiiisse von I'^vpcrinientaM'iitf ' iinjjen
znr Hrniittelnntf der liant-Sensiliilitiitshe/irko der einzelnen Hi) arks-
Xervenpaare. Sitzuiitrsh. d. k. Akad. d. Wissensch. Matli.-iiaturw. v i., VVien
<18o6), S. 8; also Deiikschr. d. Wiener Akad.. Bd. x.xxix (18(J'J).
i:
M
■ii
ij
^Hh|o<}
^^H'l
^■^^
(
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r I'" '
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r
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ii
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382
THE NERVOUS SYSTEM.
as Slierriuf^ton points out, U> the ditticulty of understunding
the experiiiK'iital notes and drawings left by Tiirct;, and pub-
lished postluiniously. Tiirek made out distinctly the bandlike
areas of distribution, but ])robably went too far in stating that
each spinal nerve lias an area of skin belonging to it, which is
sui)plied l)y it exclusively, lie recognized, iiowever, that many
of the spinal nerves have a field whicli they supply in common
with some other spinal nerves, and he even made out that the
nerves of the upper and lower extremity have no exclusive areas
but only common ones.
Of the recent studies may be mentioned those of Walsh,*
llerringham,f Paterson,;); Sherrington,* and others.
Sherrington's studies are most painstaking and elaborate,
and include ex])i'rinients uj)on a large number of frogs, cats,
and moakeys. He proceeded as follows: Finding that section
of a single root did not cause complete ansesthesia anywhere,
but only a diminution of sensation, in order to determine the
exact peripheral area of distribution of the dorsal root of a
given spinal nerve he cut two or three roots above and below
the root in which he was interested. Thus, to determine the
area of distribution of the fourth thoracic root he would cut
the second and third thoracic roots and the fifth and sixth
thoracic roots, while to determine the area of distribution of
the third thoracic root he would cut the first and second tho-
racic roots and the fourth and fifth thoracic roots, and so on.
The zone in which sensation silil existed could be determined
by testing for refiex response. He foujul that the field of skin
belonging to each sensory spinal nerve root overlaps the skin
fields of the neighboring sjjiiud nerve roots to a remarkable
extent. " The disposition is such that the field lajis to a certain
extent over the field of the root or roots iiiimediatelv in front
*Wiilsli. .1. Till' Anatomy of llic Mnicliial Plexus. Am. .1. .M. He,
Pliila.. II. s.. vol. Ixxiv (1H7T). p. :iH7-*iS)\K
t IIcrriiii:li,im. \V. I'. The Minnie Anatomy of the I^rachial I'lexns,
Prop. Roy. Soc. I.ond.. vol. xli (IHH(i). pp. 4M-441 : also Phil. Tr. Lond,,
clxxvii (IHHT).
I Patcrson. A. M. Tlic Oriu'in iiml l^istrilmtion of llic Nerves to the
Lower Liml). J. Anat. and Physiol., iiond., vol. xxviii (18!);J-"!»4), pji.
24: ir.'t.
** Slierrinf,'ton. (". S. Kx|ierimenls in Examination of the Peripheral
Hist riliMt ion of the i-'ilircs of the Posterior K'ools of some Spinal Nerves.
Phil. Tr. liond.(M) for the Year 18!):!, vol. elxxxiv. Loiid. (1H!M). pj.. G41-76:\
GROUPIN
GliOUPING AND CHAINING TOGETIIKIl OK NEURONES. 333
of it, and to a certain extent over the field of the sensory roots
immediately behind it. These two overlaps may be termed
respectively the anterior oirrlap and the jxhsieriur overhij) of a
sensory root tield " (Fig. 1!)1).
Sherrington further finils that although in a plexus each
spinal nerve root aifoi'ds separate contributions to several nerve
trunks, the cutaneous distribution of the root is composed not
of disjoined patches but of patches so connected with one
another that the distribution of the entire root forms a con-
tinuous field.
When at its simplest, as in the thoracic region, the shape of
the cutaneous field of a dorsal root is that of a horizontal band
with almost parallel edges, wrapping half way around the body
between the mid-dorsal and mid-ventral lines (Figs. 192, 193).
This simple zonal shape is departed from in maiiy places,
owing probably to the modification which the l)0(ly segments
have individually undergone in tiu^ development of the con-
figuration of the animal. This deviation from the simple and
regular figure is due in vertebrate forms largely to the out-
growth of the limbs, but with care the root fields can be toler-
ably accurate! defined in the upper and lower extremity.
Here the zones can approximately parallel to the long axis of
the limb, which is not surprising when the mode of origin of
the limb in the embiyo is coJisidered.
Reflex rea<;tion is much less easily elicited near the edge
of a field, in Sherrington's experiment, than in other parts of
each spinal field.
In addition to the (inferior overlap of a sensory spinal skin
field into segmejital fields anterior to it and the posterior over-
lap into fields posterior already mentioned, each one of these
fields has rro.s'sed orer/aps passing into the fellow field of the
opposite half of the body, both at the mid-dorsal and at the
mid-ventral line. Since the fore and aft overlaps are very
marked, Sherrington concludes that each point of skin through-
out the body is supplied l)y at least two sensory s])inal roots, in
some regions by three. Sherrington denies that the cutaneous
fields of the sensory spinal roots correspond closely with the
fields of distribution of the motor roots in the skeletal muscles.
He states further that the sensory spiiud fields do not corre-
spond with the fields of cutaneous distribution of the motor
root as judged of by the pilo-motor fibres of those roots. On
i
',i?pi
■i?
i ■
!
ill
I'm. Id'J.— -( 'ul:iiic(iii> tii'lil - iiI'ddrsMl riHii> ni -.pin;!! nci'Vr> nf niuiiUcy. hursil vnw. I hi'
aiilcricir hiinlii-^ (iT till' -kin lii lil> aiv niarUcil cm llic Id't IimII' cif ihc cast-.. Ilic |Mi>lrrinr
iHirilci-- (111 llii' liuhl hair. ■ Al'tir ( . S, sluiiiiiytciii. I'liil. I"!., I.iukI,. isitj vol cIwmv.
I'l. M.I
r .■»;.
'fl
%^
l!
/I
i
1
I 1:
1
1
Ki(i. l',i;5.^('iitain'ipiis (icids nl'ddrsil runts (if siiinal ncrvt's nl' inonkcv. \ iiitni-latcial vi
(AIUt I'. S. Sluriiii^itiin. I'liil. Tr.. I-..ii(l., l.SD-J, vol. clxxxiv, I'l. M. i
yits
li
33«;
TIIK NKRVOUS SYSTKM.
the otlier hand, the i)ilo-inotor tiekls of the synip.ithetic ganglia
and the cutuneous sensory fields do correspond.
A more recent and apparently very extensive paper by Sher-
rington I iiave thus far been able to consult only in abstract.*
In this article Sherrington discusses, in addition to his experi-
Fl(i. lilt. — Mode ofdistrilmtioii of the ilursil rout titirt's of tli<' lower corviv'al iind
tlior.icic nerves. ( After W. Tliorl)urii, from A. van (leliueliten's Ansitoniie
(111 systenie nervelix, etc.)
mental studies of the distribution in the skin and muscles of
the Xn. cervicales and upper Nn. thoracales of monkeys, the
results of some investigations which concern the N. trigeminus
and also the behavior of the spinal reflexes in total transverse
* Sliprriiigtnii. ('. S. T'lxpcriiTionts in Examination of the I'eriplieriil Dis-
tribution of the Fibros of the Posterior Hoots of some Spinal Xcrves. Part
IF. Phil. Tr. liond.. B. (1898), vol. cxc, i)p. 45-180. Abstr. by L. Briirs in
Neurol, ("cntralbl., Lcipz.. Bd. xvli (1898), S. 1041-1040.
r.rif ■
'' '.
GROUPING AND CHAINING TOGKTHKll OF NEURONES. 337
losioii. 8horriii<?toii lius employed largely his method of "it-
maiiiiii;^ ana'stlicsia " in order to avoid tiie confusion resultiiif;
from " overlai>i)in<^." Electrical stimulation and studios of de-
generated fibres by osmium blackening were also made.
So far as tlie subject now being considered is concerned, the
second chapter of his article interests us most — that dealing
with the relation of segmentation to the innervation of the ex-
tremities. On superficial examination one might be led to
believe that considerable differences exist as regards the limbs
in the areas of distribution of the motor and sensory roots of
^iven spinal nerves. The areas of motor distribution form con-
I'"l<i. IStf). — Mode of (listi'il)Uti(m of tlic diiisil root lilirrs of tlu' lowiT corvical
nerves and of the tlioracie nerves. ( After W. Thorhnrn, from A. van Ge-
huchton's text-liook, )
■:l
!
iff
,: t
i
- , ...•"••►■
/i
1
tinuous zones^, all beginning at the middle line of the trunk
ami extending for a longer or shorter distance into the extremi-
ties — that is to say, the same ventral roots of spinal nerves
33
Hi
'11
1 1 H i ;
II I
m
i' ' I?
li
I
'■i<
338
THE NERVOUS SYSTEM,
wliich iiinerviite muscles at the tips of the extremities also in-
nervate some muscles of the trunk. The areas of (listril)uti()ii
of the dorsal roots (sensory) a])j)ear, on the contrary, to he
separated entirely from the trunk ; thus the cutaneous areas
supplied by the seventh and eiffhth cervical roots and by the
first thoracic root, for example, nowhere reach the trunk.
Sherriufftou proves, however, that this ditfcrence exists only
between skin nerves and motor nerves, not between sensory
nerves in general and motor nerves, for thoufjh the sensory
dorsal roots above referred to supply no portion of the skin of
the trunk, they do send sensory branches to the muscles and
other subcutaneous structures there. Thus the areas of sensory
distribution also form continuous zones involving both trunk
and extremity. The sensory nerves for given muscles always
originate in the spimil ganglia of the segments wliich corresjiond
to the motor nerves to the same muscles. Sherrington, with
Mall, is of the opinion that the best guide to the understand-
ing of the structural relations in an extremity (arm or leg) is to
be found in the neural distribution. His studies show the fol-
lowing : (1) 1'hc degree of overlapping of cutaneous areas of
iiulividual dorsal roots varies greatly, being much more marked
in the extremities than in the trunk. (2) The intermixing of
the fields of dorsal roots is very much greater than that of the
peripheral nerve trunks, even in the hand and foot. Thus,
while there is very little overlapping of the areas supplied by
the X. medianus, X. ulnaris, and X. radialis, yet when the in-
nervation of the haiul by dorsal roots is examined it is found
that a large middle area of the hand and fingers is supi)lied ])y
all three of the seventh and eighth cervical and first thoracic
dorsal roots. (15) X certain parallelism between the overlap-
ping of the skin areas of the various dorsal roots and the
anastomoses between the derivatives of different roots in single
muscles is recognizable. Thus, in the extremities very few
muscles are monomeric (unisegmental), the majority being
polymeric (two, three, or four segments). The intercostal
muscles ai'e monomeric. The muscles of the hand and foot,
on the contrary, exhibit the most nuirked mixing of motor
roots from different segments. (4) As regards the functional
significance of the overlapping, Sherrington thinks there is
none ; the anastomoses have, on the contrary, a morphological
basis.
(iliOUPINi
'if!
(iKoriMNC AM) ('I1A1\IN(} TOOKTIIKU OF NKl'KoNKS. XV,)
1 ll
III this connection it is interesting to compiire with the
results of experiments on animals the tindings of clinicians in
pathological human cases. We refer to the researches of Thor-
l)urn,* RosSjf Dana, J Starr,** Mackenzie,|| Head," Kocher,^ arul
Cushi)ig4
Thorhurn's studies refer mainly to the peripheral distribu-
tion in human beings of tlie fibres of the dorsal roots of the
plexus cervicalis and of the })lexus lumlxvsacralis and their
corresponding segments in the spinal cord. His studies are
based mainly upon cases of traumatic injury to the spinal cord,
and his results are illustrated in the accompanying figures.
Starr's valuable analysis of a vast atnount of clinical nuiterial is
epitomized in the table, introduced in Chapter LV,in which the
lower motor neurones are discussed.
* Thorburn, VV. discs of Injury to the Cervical Region of the Spinal
Cord. Hrain, Loinl., vol. ix (18HG-'Hi). pp. ,"5 10-54:5.— On Injuries of the
Cauda Equina. Brain, Lond., vol. x (1>S87-'H)^), pp. .'581-407.— .Spinal Local-
izations as indicated by Spinal Injuries. Hrain. Lond., vol. xi (1888-'H'J),
pp. 2H!)-3!24. — The Distribution of i'aralysis and Aiwcsthesia in Injuries of
tlie Cervical Region of the Spinal Cord. Rrit. M. J., Lond. (1888), vol. ii,
l>p. 1:582-1885.— A Contribution to (he Surgery of the Spinal Cord. Phila-
delphia (1880).
■f Ross, James. On the Segmental Distribution of Sensory Disorders.
Brain, liond., vol. x (1887-'88), pp. ;5:53-;{61.
t Dana, C. L. A Clinical Study of Neuralgias, and of the Origin of
UeHex or Transferred Pains. N. Y.Med. J., vol. xlvi (1887), pp. 121-127.
* Starr, M. Allen. Local Ana'slhesia as a Guide in the Diagnosis of
Lesions of the Lower Spinal Cord. Am. J. Med. Se., Phila.. n. s., vol. eiv
(1892). pp. 15-;55; and Local .\na'sthesia as a Guide in the Diagnosis of Le-
sions of the Upper Portion of the Spinal Cord. Hrain, Lond., vol. xvii
(1894). pp. 481-512.
II .Mackenzie. .1. Contribution to the Study of Sensory Symptoms Asso-
ciated with Visceral Disease. Med. Chroti.. Manchester, vol. xvi (1892), pp.
^ Mead, II. On Disturbances of .Sensation with Especial Hcference to
the Pain of Visceral Disease. Hrain, Lond., vol. xvi (189:5), pp. 1-133;
ibid., vol. xvii (1894), Part III. pp. 339-480; and ibid., vol. xix (1896),
pp. ir)3-27r).
Koclier, T. Die X'crletzungeii der Wirbelsilule zugleich als Heitrag zur
Physiologic des menscidichen Riickenmarks. Mitt. a. d. Grcnzgeb. d. Med.
II. Chir., .Jena. Hd. i (189(5), S. 415-480. — Die Liisionen des Riickenmarks bei
Verletzuiigcn der Wirbclsiiulc. Ibid.. S. 481-1160.
1 Cushing. llarvcy \V. Ha'inatomyclia from Gunshot Wounds of the
Spine. Am. .1. M. Se.. Phila., vol. cxii (June, 1898).
t;.. I
!■ II
II I
,
1
/i
I
F
I ;
i
^r ':'
340
TIIK NKIIVOUS SYSTRM.
Tlio paper of Ross is hriiiiful of sugifi'stivoncss, and should
be read by every one who wislies to enter at all thoroujjhly
Fi<;. HKi. — >rii(lc iil'distriluitiiiii (it'tlic dnrsil rnot lilircs of tlic Iuni1):ir and siicral
iitiv<'s. lAfttr \V. 'riiiirlmrn, troiii A. vim (icliii<ditt'irs ti'Xt-lMmk.) A, vcii-
tnil aspect : I!, dorsal aspect.
into tlie l)i])lio<;ra])hy of sensory localization. Scarcely less
interestiiiir are the accurate observations of Danti witli re<;anl
to tlie ])aiii a('('oni])anying visceral disease, and Starr is ri<:;ht
in his complaint that too little attention has been paid to
Diina's studies in subseqnent investigations npon the same
sul)ject. A comptirison of Dana's ditigrams (Figs. 107, li'N)
with those of Head, Thoi-l)nrn, Starr, and others, sliow how
closely the idetis of a hiter date correspond with those advanced
by him in 1887.
OUOUl'lN
iHnt'T
U1U)L'1'1N(J AND (;11AININ(J TOdKTllKli OV NKUUoNKS. -541
The cxtcfiulod stiulii^s <»f I load are very injjcnious, iind have
attracted widc^sprcad attcsiitioii. He, like ClilTord Allhiitt, Ross,
Dana, and otlu-rs, had noticed that tlic cutaiicoiis tenderness
(patliolo^^deal associated sensations) accompanying certain dis-
orders of the stomach tend to occnpy definite tracts of skin
with (h'linite honkM's. Tins U'd him to investigate the j)ain
and accompanying tenderness conse(|nent npon disturhances of
other organs, and he fonnd that tiiese sensory distnrhances als(>
followed delinite lines. Stimulated l)y the suggestive papers of
Ross, he thought it prol)ahle that these areas nnght hear some
delinite relation to nerve distribution, and with this in view
studied the distribution of a large nund)er of cases of herpes
zoster, hoping that they might throw some light upon the sig-
nilicaiKie of the tender areas in visceral disease. To his surprise
he found that the areas occupied by herjjes zoster corresponded
exactly to those with which he was familiar in visceral disturb-
ances. Further study showed that the areas represented the
distribution of either a single nerve root or a segment of the
spinal cord.
Head inclines to the view that the distribution of the nerve
roots is somewhat different from the distribution for the seg-
ments inside the sj)imil cord. His reasons for thinking so are
briefly these : Whereas Sherrington found that the areas of cuta-
neous supply from any two roots definitely overlapped. Head
states that his areas do not overlap at all, or if so, only very
inconsiderably. Sherrington's areas, it is true, apparently repre-
sent the root supply for the sensation of touch, while Head's
areas correspond rather to pain sensations and trophic sensa-
tions. It might be assumed that whereas the distribution of the
fibres for the sensation of touch in the various dorsal roots over-
lap considerably, those for pain do not overlap. Sherrington,
however, states expressly that he nsed touch and pain stimuli
indifferently as a test for the presence or absence of sensation,
and Head feels sure from his observations in five instances of
surgical division of a single dorsal root in man that not only
was there absence of ana'sthesia to touch after division, but in
most instances the sensation of heat, jiain, and cold was also
not materially disturbed. Head believes, therefore, that where-
as Sherrington's areas represent the true root supply, his areas
correspond to the su])ply, not of roots, but of segments of the
spinal cord from which the roots in ])art arise. He believes
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Anifinia.
Emloint'tritis.
Bladdery
Constipation
<'nricH of incisor,
Error of oyo-rofraction.,^
Gaptrir dyspi-pBia
cured by acids.
"' /_^ Decayfid teeth.
-/,<i'-_,Pharytiu'iti8.
',' ,-' Otitis media.
I'spudoancinn, of
;;aHtric oriyin.
pnsm8 of
,' Ureter.
Fio. 197.— Referred pain in visceral disttirbiinces. (After C. L. Dana, N. Y.
MiMl.Joiir. for July 30, 1887, p. 125.)
342
Uver.
Nrurartlu'iiia A/
(spinal irritation), fh^^
Liver.
Splenitis.
Stomach
Uterus.
Broad liKamRntB|---'/p
and ovaries. I i
T.ilhirmia.
Neurasthenia.
Ovaries f
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344
THE NERVOUS SYSTEM.
N-tti^
\im
III
CVII
C VIII
Fio. 199.— Arcms of itaiii scnsjitioii in visccnl discaso. (Aftor II. Head, taken
from W. ().s.iT, T'lc rrimiplcs and IVactico of Medicine, M ed., N. Y., 1SU8,
p. 910, Fig. 7. )
ifli
(illOUPIN'G AND C'lIAINLVG TOGETHER OF NEUUONES. 34,5.
CVII
evil
Fici. 200. — Aroas of pr.in sons'iticm in visccnil discnso. (AtU'r H. Ilciid, taken-
from W. OsliT, Tlie rriiicipU'S iiiid Practice of Mediciiie, 3d cd., N. Y., 1898,
I). «U, Vig. 8.)
i
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'9.
li
hH
Mis
Hi
;}4tt
TllK NERVOUS SYSTKM.
tliiit the mechanism for tlio sonsiition of touch in the various
spina! sof,nnents must ovorhip, while that for the sensations ot'
pain, heat, and cohl does not overlap, at any rate to the same
extent. The areas as outlined l)y Head are indieate<l in the
accompanying; dia}j;ranis (Kigs. 1!)I», 'H)()).
The h)calization within the spinal cord caii not, liowever, 1)e
said to he satisfactorily settled, and much research is still
necessary.* The clinicians often have considerahki ditticulty
ABC
Supnt-
tiaviruldr.
.r.-'-S
Midial
cutaneous
■ Axillary.
\\
l6oi'e fi C.
Mvilial
cutaneous
J'itlmiir
ulnar- -
Ulnar
Litti rill
cutaneous.
-Palinar
median.
Radial.
Med' in.
SC-1 T.
IT.
,C.6
Fio. '.JOl. — Types of aiiii'stlu'siii. A, pfrii)lu'r!il i from llusst'^; R, spiiiul, root
type of ('liii)iiiilt (from Koclicr) ; (', ccrt'ljnil, nu'dulliiry typo of Cliipault
(from Hrissjiiulj. (After 1'. ('. Kiiapp, Tr. Ainer. Neuroi. .\ssoe., 1897.)
in deciding as to the site of a lesion which causes disturl)ance8
of sensation. These difficulties have recently been discussed
in an instructive paper by Knapp.f It is especially in eases of
syringomyelia that the findings may be puzzling. In the dia-
* An interesting^ recent paper is that of C. E. Beevor, The Distribution
of Motor and Sensory Syin|)toins from Injury to the Roots of the Brauliiul
Plexus. Tr. M. Soc.^ Lend., vol. xix (1896), pp. 72-7!).
f Knapp, P. r. Anipsthesia in Diseases of the Spinal Cord. Tr. Am.
JS'eurol. Ass. for 1897. New York (1898), p. 81.
?(
GROUPING AND CHAINING TOGETHER OP NEURONES. 347
Fig. 802.— Regioucs corporis liumuni. {AC it W. His, Die anatomische Nomeu-
clatur, Leipz., iS95, Taf. i.)
■^■^'
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348
THE NERVOUS SYSTEM.
R.ULrvtmaIi.\
Fossa rftivmtdlfoUurs tatrni
H.rrtrantaZitvtarvi laUrahs
Fig. 203.— Ri'giones corporis huinani. {.\ftorW. Hi.s, Die iinatomischc Nouien-
cliitur, Leipz.. 1895, Taf. ii.)
iii
(iR(»riMN(i AND fllAIXING TOGETIlKll OK XKUJKJXKS. ;j4y
gram (Fig. '-JOl), (■f)ml)ii\»Ml by Kiuip]) from Viirious sources, the
so-callod })('rij)lu'ral, spinal, aiul ciM-chrul types of una'sthesiu in
the left arm are indicated. A lesion of the cerebral type can
be duo not only to diaoases of the cerebrum, but to lesions in-
side the spinal cord.
That the areas of cutaneous sensory disturbance do not cor-
respond to tlie regions on the surface of the body wiucli have
been defined by the topograjthical anatomists will be (dear from
the accompanying diagrams, \vhi(di are here introduced for con-
venience of reference (Figs. 'H)'i, 'H)'-]).
/I
1
J
:,
j
(
1
1
:illiil
(A) Centripetal Neurones of the First Order collecting Bodily
Impressions.
CIIAITKR XXVIII.
PEUIPIIKIJAL CKNTKIPKTAL NKURONKR.
ReUvtioiis of poriphcriil ccntri|iftiil iiouroiu's to the central iiorvous system —
The sensory spinal nerves — The sensory cerebral nerves.
Thk neurones collecting bodily impressions will first be de-
scribed. Part of tlieni are connected witli tbc spinal cord, the
remainder with the rhombencephalon. There are, as every one
knows, thirty-one pairs of spinal nerves, including eight cervical,
twelve thoracu(s five lumbar, five sacral, and one coccygeal (Fig.
!i()4). If we include the two rudimentary coccygeal nerves, which
Rauber has described, the total number is increased to thirty-
three. All of the .spinal nerves have ganglia upon their dor.sal
roots (Fig. 205). It is in these ganglia that the cell bodies of
the spinal peripheral sensory neuroiu>s are situated. Of the
cerebral nerves not all possess sensory functions ; outside of
the organs of spe(fial sense only those which are provided with
ganglia in their course are known to carry centripetal impulses.
Excluding the nerves of special sense — that is, the olfactory,
optic, and cochlear nerves, and the nerves concerned in the
sense of taste (portions of the glossopharyngeal, trigeminus, atul
nervus intermedins) — we have left as sensory cerebral lu^rves the
sensory portion of the nervus trigeminus with its ganglion senii-
lunare (Gasseri), the nervus intermedins of Wrisberg with its
geniculate ganglion, the nervus vestibuli with its ganglion ves-
tibuli, the nervus vagus witli its ganglion jugulare and ganglion
nodosum, the nervus glossopharyngeus with its two ganglia (gan-
glion superius and ganglion petrosum), and occasionally, per-
haps, a portion of the hypoglossus nerve, since in the embryo
at any rate it is sometimes provided with a sensory ganglion
(Froriep). In these various ganglia are situated the cell bodies
a50
1^
Fig.
"^
HI'S
Fi<i. ~0l. — S|iiiial cnnl hi I'niiiK'clinii uIhivc willt
till' iiK'diilla iililiinuiila ami |iiiiis. (Afli-rA. Kaiilicr,
l.i'lirlxirli (liT Aiiatipiiiic <lis Mciisclicii, V. Aull.,
I,iil>/... IHlw, U(l. ii, S, 501. Kin. tsr.. ) I'. N.iviis
triufiiiiiiilM ; ,\7/, ni'i'viis liyiiinjlnssus ; r,, ('h-nI ccr-
viiiil iici'vc ; r .'-,s, sccdiid tiMiulilli ctTvical iicrvr ;
T I I .'. tii-st tiitwiirtli lliiiracic nerve : /. /-.■;, lirsl \i>
lil'lli liiniliar nerve ; SI .■;, (irsi tn til'tli sieral nerve;
C, Nervus eiHcyKens ; x, .1, liliini lerniinale nf the
spinal eiinl. Fnini the rcmt niarkeil I,, tn r, eanda
eipiina ; llr, plexus liracliialis ; (V, Neivns feniu-
ralis: Nc, Nervus iscliiadieus ; O. Nervus idilurato-
rius; the enlarK<'nients oppipslle L '.i. I. and ."> rep-
resent the spinal K^mulia mi the dmsal runts. On
the left side iif tile IlKUre the s.ynipat lielie tnilik is
sIkiwii. (I til -ix are naiiulia ; n, Kaii;;licin eervieale
siiperilis : h and c, Kan^liiin eervieale niediiini et in
I'eriils ; il, first tlmraeie tiiinulimi ; </'. last lliniaeic
KaiiKlion ^ '• 'ii'^t lumliar f^auKlinn ; "i. lii'sl siieral
gaii}iliiiii.
'T
a 12
V^s
ss\
y^'
\^
Fig. 204.
Fl(i. !i(tr). — rortiiins of the pars cerviealis of the
sjiiiial eord with nerve roots. (.M'ter .\. liaillier,
iiehrliileh der Anatoniie des Meiisclieii, V. Aull.,
Leipz.. ISilH. Hd. ii, S. '>Ki. Fin. 24S. l A, spinal eord
.seen from the ventral surface. On the ri^lit side
the ventral tila radicularia have heeii cut through.
H, spinal cord seen from the lateral surface. — /,
ventral median tissure ; .,', dor.sal median sulcus: .;,
sulcus lateralis veiitralis, whence tlii' ventral lila
ra.dicularia emerne : .(, sulci laterales dorsales
throUj;li which the dorsal root lilires enter the spinal
lord: •''. radi.x veiitralis ^'linK !«ist spinal ),'anj;lion
cut throiifjli on the rifjlit side in Fi^. .\ ; C. radix
dorsilis enierKinn from the fian^dioii spinale (6" ) ;
7. N. spinalis immediatel.v after its formation
throiif.'h the union of the i-.ldix ventmlis anil dor-
silis dividing into 7. a ramus veiitralis, and <", a
niniiis dorsalis. The ramus coniniuiiicans and tlie
ramus mt'iiiiigciis aiv not shown in this tif^ure.
It
Hi
TIIH NKUVOUS SYSTKM.
of tlio peripluTiil sensory nouroncH, of the variety under diseus-
sion, pertaiiiiiif; to tlie rhonilu'iiccplmloii.
It is especially to be noted that, if we leave out those
{^'uthered iroin the viscera l»y means of the sympathetic nerves,
nil the impressions collected at tlio periphery of the body and
!'■< '
III
■imim
VlG. ~(lli. — Sclii'iiu' of pcriplicriil spinal sensory nciiniuc sliowinK tlic iicriplicrnl
process, il, extending to a periplunil sensory surface /» and a central axoncc,
enteriii}; the spinal cord tlu'oujili the dorsal root ofa spinal nerve there hiflir-
catinjt at c into an ascen<linK and a descending liinli which t;ivc otl" numerous
collaterals. The cell hody is shown in the spinal KiU'jilion (,'. Other neii-
rom's are schematically slu)wn, hut ne('<l not he considered hen'. i.M'terS.
Hamou y Cajal, Les nouvclles idees, etc. Translated hy Azoulav, Paris, 1894,
I>. 2.-), V\ii. ti. )
from the ijiternal organs are carried into the oentrtd nervous
system (spintd cord and hniin stem) by means of one set of neu-
rones (Fig. '2W>). The total number of individual neurones
m
0I10UIMN(} AND ('IIAINM\(} TOOF/riIKU OK MirilONKS. ;{;-,;{
(•onci'nu'tl is ciioriiinus, l)iil there is no siiperiinpositioii (if m-u-
ront's in the nu'chanisni hen- deseribed. A centrijx^tal impulse
orijiijmtinf,' at tho periphery reuclies the primary end-stution of
the sensory neurones insicU; the central nervous system after
liavinj; passed throuj^h oidy one neuroiu". Althou^'h for the
orii^in of any j^iven sensation centripetal impulses start at the
periphery, usually in a considerahle nundjer of dilferent neu-
rones, each of these extends as fur as some j)rirmiry end-station
inside the (central nervous system, not requiring to puss through
any secondary neurone on the way.*
* Tiiis is ill all protmbility not Inm of the sensory iinimlsus collected l)y
menus (if tile neurones of the synipiitlielic system ; tliese im|iiilses, it is prol)-
aljle, puss tiu'oiiyli ii elmin or series of indiviilual neurones liefore urrivinf?
in the cerebrospinal system. They are earried by means of ilie rami eom-
iinmieantes into the dorsal roots of the spinal nerves. Theii' fiirtlier faie is
not yet elear. Some of the synipatiietie axones end wiliiin the spinal
ganglia ubont the l)0(lies of spinal ganglion cells, and the centripetal im-
pulses which they carry coiilil then lie taken into the spinal cord liy nu'ans
of the central prolongations of the spinal ganglion cells. It has liecn as-
serted by some investigators that a certain numlier of sjmpalhetic axones
jiass from the ranu eommunieanits directly through the ganglia, or past
them into the dorsal root* ami so into the spimd cord without intcrruptitju.
More research is necdeil before entirely satisfactory statements can Ije made
regarding these points.
V
%.'■
Si
iMilii
CIIAITKR XXIX.
a KN KKA L DKSCKI I'TIUN.
Tlie s|iiiiiil piiif^liii — Hipolar cells in cinljryu — riii|i(iliir I't'lls in adult —
IVriplu'riil scnsorv iil-ri's — Central axoiies to dni'sal fmiieiili — Fibres
C'xogciu's of 1*. Marie — Nuclei teriiiiiuiles — I'liylotrenetie stmlies — The
structure of liuinau spinal piujiliou cells — Studies of v(iii Leiiln^ssek,
Lugaro, and N'issl.
1. Centripetal Nt/urones of the First Order (collecting Bodily Impressions)
connected with the Spinal Cord.
Tin; ])erikiiryon8 of all the sensory neurones that we are de-
scrihiiig are situiited outside the central nervous^ system (ii\
human heincjs) in marked contrast to tlie cell bodies of the pe-
ri])heral motor neurones, which are situated within thecoliimua'
grisere of the spinal cord. In Section IV the emhryological
orifjin of these neurones has been described. It will be re-
called that in the human embryo they a])])ear near the spinal
cord and soon come to occupy positions lateral from it. At a
very early period the distal and central processes of the s])inal
ganglion cells are recogniziible. It has also been pointed out
that there is a gradual transition in the end)ryo from the bi-
polar condition of the cells to the uuijiolar condition Mliich is
characteristic of the adult. In considering the anatomical dis-
tribution ajid physiological functi<tn of these ])eripheral sensory
neurones their bipolar nature has ever to be borne in ini-nl, tiie
unipolar condition of the adult being the result simidy of an
attenur.tion of a portion of t'..e cell body, doubtless tin example
of adaptiUion to environment, but whether for economy of
room or for improvement of nutritive relations we do not know.
It has been stated that the distal process of the spintd ganglion
cell grows to the ]ieri])hery iind beconu's the tixone of n periph-
eral sensory nerve fibre, or, since it often divides, it mtiy take
part in the formation of many peripheral sensory nerve fibres.
854
GUOUPIX(! AM) ("HAININfJ T()(iKTIFHR OF NErHONKS. 3;,-,
TIh' cc'iilnil j)rol()iigiiti(iii of the s|)iii!il <,';iii<j;li()ii roll <j;r()ws di-
rectly into the spiiuil conl. 'I'he total mass of eentral ])roloii-
pitioiis from a sinjjle pint^dion forms tlie dor^^al root of one
spinal nerve ( Fiij. '^OT). Tlie dorsal fascii-nli of white matter
within the spinal eord are huilt up in the main of the intramed-
(i. .ip.
Via. :2()7. — SiiKin.'il sect ion tlinniKl) seven spiiiiil ^'miikUm Dl'finlivyci nmnsi', 10 iimi.
1(111;;. ( Vrvieal reninii. Mi'lliml (if ( iiilKi-lvMiie 11. dinilile iiii|iiiv;iiMli()ii.
l're|iMr;iliipii mikI drawing 1).v ( '. II. iiiinlin,!;. il. /•../'., dinsal iimiI lilno; (i.Kp.,
fliiiiKlieii spiiiale ; .1/. .s.. medulla spinalis.
ullarv proloiijjjations of the dorsal root fibres. They are thus
fornu'd ehielly of fil)res extrinsic or exoi^enons to the cord
[jibi'i'x r.rot/riir.s of V. Marie). These dorsal root fibres some-
wliere in the eord, medulla, or cerebellum end by ramifyinjj
ainouif aiul upon the cell bodies (perikaryons) and dendrites of
other neurones in what we m)w call the iiuclci Irniniidlrs, or
the " })rimary en<l-stations of the sensory comUuition paths."
This description holds <.^ood for tlu' ju'ripheral sensory neu-
ii
[if
m
Mr.o
TIIK NEIiVors SYSTEM.
:^MI
rones of the cerebrum iis well us for those of the cord. There
too the cell bodies are situiited outside the })raiii in the ffauj^liji
on the eerel)rid nerves, the i)eri})lieral prolonj^atioiis run to the
surface of the body as niedullated lil)res, the niedullated central
prolon>i;ations run into the nerve centrer to end in the prinuiry
end-stations or nuclei of termination of the (cerebral nerves. In
the last are situated the cell bodies and dendrites of other neu-
rones (of the secoiul order) which can take uj) the impulses and
carry them further.
While it is true that nearly all the embryonic bipolar cells
of the spinal and cerebral sensory ganj^lia become later unipolar
in Inunan beinj^js, in many of the lower forms, for example in
the lish, they remain bipolar throu^ihout life. It is interesting
to remember that in the ganglion vestil)uli of human beings
(as well as in the ganglivyU cochlea') the bipolar condition is
retained throughout life just as in the fish.
l'hylogeneti(! studies have excited a great deal of interest 'n
(ionnection with the original position of these peripheral si'U-
sory nem'ones.* In some animals like Lnnihriciis the cell bodies
of tlie sensory nenrones are situated in the epithelial surfaces
of the animal (Fig. ^OS), the short jjeripheral process or den-
drite passing between the other epithelial cells toward the sur-
face, the central prolongation running from the skin into the
nerve centres. Other animals (like 3Vvv'/.s) possess neurones in
which the cell body is no longer located in the peripheral epi-
thelial surfa(!e, but is situated near it, or at various points be-
tween it aiul the central organ. Tlu' further the cell body
from the epithelium, the greater of course is the length of its
distal process. In human beings, as has been stated, and in
other mammals the cell body is almost as far distant as possible
from the i>eripheral surface, inasmuch as the spinal ganglia are
very close to the central cerel)rospinal nervous system and very
far removed from the peripheral sensory surfaces. One verte-
brate, amphioxus, is peculiar in that its bipolar sensory neurones
are situated within the s])inal cord (Retzius). There are ani-
mals — as, for example, I'tcrnlrdrhca — which in a comparatively
limited space show a whole number of transitional stages bt'-
, ,^.
* Cf. Uotzius. 0. I'eboi' dio iicucii Priii/i|iieti in ilcr lA'lirt' v<iii ilcr' lliii-
richlung dos scnsil)loii Nervensysteiii.-i. Biul. Uutersucli., Stui'kholiii, n. I''..
B.l. iv (182<J), S. 49-56.
(JROUPIN'd AND ('I1A1XIN(} T()(!KT1IHR (»F NKUllONKS. 357
tweon the peripheral position of the eell liody and tlie central
(K(liii^er). It is of the fjfreatest interest to lind that in human
beinj^s we have one instance (in the domain of the special senses,
however) in which the cell body of a })eripheral sensory neurone
is situated amon<^ the epithelial cells of a sensory surfav-e. I
refer to the cell bodies of the peripheral olfactory neurones
(Fig. 157, ri<h' supra, p. "■>(;:>).
The ganglion spirale and ganglion vestibulare in hnnian
beings present stages transitional between the peripheral olfac-
tory neurone and the ordinary peripheral 'sjjinal neurone, since
5/-
rni
Fio. '.iOS. — rcrijilicriil (•ciitriiictal iiciinnics of viirioiis iiiuiiiiils. ("After f!. R«'t-
ziiis. liiol. rntcrsiicli., Sti.ckliKliii, 15(1. iv, isit^, S. 5t). Kijts. I, •„>, :5. and 4.)
.1, oliKiicliii'tii' woi'ins I I,iiml)riciis I : />', pulycliii'tic worms iNcrcisi; r, mol-
liiscs ( Liiiiiix 1 : l>. vcrtchratcs. Tlic Krailiial cliaiiKc in llic position of tin-
pcril\aryon in llic pliyloKcnctic scries is inlereslinj;. c. epillielial eellsof sen-
sory surface ; c, cii'MMila : a:., periliaryon of periplieral centripetal neurone;
)•(«, retc .Malpljiiiii « f epidermis ; sii. axone ; vii. central nervous system.
the cell bodies of the neurones in these ganglia tire situated
out near the sensory surftici^s, whence they collect impressions,
though not iictually in them.
The structure of the cell bodies situtited within the spinal
ganglia has been described at some length in Section III and
■rw
Ji
<r
11.
r;(
/i
i
iifJ
WW
{!'
•\ til'
','• ' y ''i
!■•
m
358
THE NERVOUS SYSTEM.
iietMi nut be discussed agiiiii here. In Ki<,'. '^i)'.) is shown a large
type of cell from the liiunan spinal ganglion taken from v(jn
Lenhossc'k's recent article, and in Fig. '^'lO certain other types,*
For accurate measurements of the dimensions of the spinal
ganglion cells of ditferent animals, adult and endjryonic, the
reader is referret' tc the article of Cavazzani.f
The meduUated peripheral prolongations of the spinal gan-
glion cells run, along with tiie meduUated motor axones, out
into the peripheral nerves (Fig. ^05 ; vide fnijjia).
If ■■■■ A^^fe^^w^^-'^
—s
p-
IL
Fio. "^O!*. — Liii'fic spiiml fritiiKlimi cell from ;i healthy man with (•(iiuicctivc-tissne
capsiih'. (Al'tir M. von I.inhossi'k, ISlHi, taken iVoiii A. Kaiilii r's text-hook.)
StainiiiK with toluiiliii hhie and eosin. .s', (■n(hptiieiial sliealh; )t, periipheral
ch'ar zone ottlie piotojilasm ; A-, axoiie iiilloek : jt'i, pigment.
In the dog five distinct types of cells in the spinal ganglia
have been described by Lugaro.J The ty])es to be found in the
rabbit have been carefully studied and described by Xissl.
After dividing a Viiriable number of times, these meduUated
* von Leiiliossi'k, JI. lT(>l)er den Ban der Spinal.ViUijjlionzelh'n ties Meii-
sclien. Anil. f. Psyeliiiit. ti. Xerveiikr., IJeil.. Bd. xxix (1896-97). S. ;i46-:380.
f ('ava/./iini. E. liitorno ai gfinijli s|)in!ili. Arch. ital. di clin. iiicd., Mi-
lano, vol. xxxvi (1S97), pp. 41 -o:!.
X Ltiffaro. E. Siille alterazioiii delle cellule nervose del jjan^lia .spiuali.
l\iv. di patol. iierv. e ineiit., Fireiizc, vol. i (1890), Nos. 8 ami 13.
GROUPING AND CIIAIXIX(} T<)(;CTIIEH OP NKUIIONKS. 359
axont's roiU'li the pcriplu'nil or^'aiis, wlionco tlicvrolloct ci'llulip-
etal iiiii)iilsi's. All of tlifso pcriplionil llbres uiul ircc ; tit uiiy
rate, we have as yet 110 evidence of connection />// con/ in 11 if// of
the termination of one of these fibres with any other cell. That
m
: i
%
■■h\
■fPm
7 A*.i.\
*» 1.*
■^ -I '^
<-'a' •
C
D
/A<.
; . . .■- •^;v<;:^■••'■A;;i^.•:, •. . .,
'^ :■■^•;^•■^:i!^^t:•v.v^/
■^-^
^^:^i
1/
IS^*:*^,
'*-wi
1
^./
ri(i. :JIO. — Scvcriil typi's of si)iiiiil j;aii;.'Iiiiii cells. lAI'lcc M. vmi licnlinssi'k,
Aicli. r. I'sycliiiit., 15(1. xxix. lSilii-'!»7. ) .V ami T), small rlinimniiliilc spinal
fiaiiKlinncclls, siimcwhat slirimkcii ; H, mcil i 11 iii-si/.cil spinal trail jil inn ct 'II with
ciiars'' tiKi'did masses; it, piumcnt : (', larjre pale cill, perii)li('ral ;;arlan(l of
titjriiid evident ; K, small ehnimnpliile spinal {ranulion cell, interidi" nt' eell
jireseiits a lionio^fneous appearance, >;ailaml of tigroid masses at the pe-
rii)iier,v.
the pcriphenil endiiifjs may iictuiiUy i)onetrate into opitluOitil or
other cells seems likely from the studies of Knjjfclmiinn, Ajjiithy,
and others. The modes of ending in the peripheral organs are,
liowever, very varitihlj.
ji
;ii|iii|ii|i
ar.o
TIIK NEItVOrs SYSTEM.
It WUK long thoufflit tlmt gim<fli(>ii cells were situated in
Meissner's corpuscles in the skin, in the so-culled Tasfzcllfu of
Merkel, ami in other peripheral end organs, and that these send
their uxis-cylinder processes into the nerve (centres. Hut this
view has been shown to be false. The peripheral prolongations
of spinal ganglion cells end free in the shape of disklike ex-
pansions in these structures.
On account of their functional relations the so-called sen-
sory nerve endings might be, perhaps, better called peripheral
nerve beginnings.
No less than one hundred and eighty-five articles concern-
ing the endings of sensory nerves ii. vertebrates have recently
been collected and reviewed by Kallius, of (Jottingen.* As this
author states, the ditlerent varieties of nerve endings nuiy be
classified in diiferent ways, either according to the eiulings
themselves or to the tissues in which they are situated. They
iiuiy terminate independently of any special end organ, or the
free endings of the fibres may be inclosed in certain definite,
specially ditferentiated, terminal corpuscles. The most con-
venient method of describing them is as (1) those incident to
epiblastic and hypoblastic structures, and {'i) those incident to
mesoblastic structures.
* Kallius. E. Eiuliguiigeii sensibler Nerveii bei Wirbeltiercn. Merkel
Homiet's Erf^ebn. d. Anat. u. Entwickelungsgeseh., Bd. v. (1895). Wiesbaden,
l8t)G, S. 55-94.
■
II!
hi:
CHAPTER XXX.
THE MKDl LLATKM I'KKI I'll KKA L AXOXKS OF TH K IM'.HI I'll KUAL
I'KXTKIPKTAL N' KUKON KS AND THKIK TKKMINAL A IM'A UATIS.
C'eiitripi'tal lu-rvc eiidiiif^s or beginiiiiif^s — ("Ijissiticutioii — Xorvt; hcgiiiiiinj^s
ill ('I)il)lasti(' and hy|M)l)l)islic' tissues — Naked bcginiiiiiKs i" I'pitlit'liuin
— Kpidcriiiis — Mucous ineinbniiK's — End-platelets — Merkefs Tastzellen
and Taslnienisci — (irandry's eorpuscles — Nerve beginnings on hairs,
hair follicles, and teeth — Nerve beginnings in lung, liver, pancreas, stom-
ach, and intestine — Nerve beginnings in niaiuniary gland.
Sensory Nerve Beginnings in Epiblastic and Hypoblastic Tissues.
Is tlio skill tlu> fibres representing divisions of peripheral
prolongations of spinal ganglion cells lose their myelin sheaths
before entering the epithelium. Once inside the epidermis,
they branch typically, giving off first tangential brunches, from
which secondary finer divisions pass through the stratum ger-
ininativum into the up])er layers. The individual fibrils can
pass upward or downward, l)ut always, or nearly always, end in
the epithelium itself. At the tips of the individual fibres very
fine bulblike processes are often seen. Many believe that the
nerve fibrils end inside the epithelial cells. Certain it is that
the nodules can lie seen pressing into the surface of the cell,
but that they actually are to be coiisidered as intracellular nerve
endings is at present doubtful. The weight of evidence is, on
the whole, against this view.
In mucous membranes covered by squamous laniellated epi-
thelium—for example, the tongue and oesophagus (Fig. 211)—
the relations are similar to those in the epidermis. Retzius *
has pointed out a peculiarity of the terminals of the nerves in
* Rotzius, G. Ueber die sensiblen Nervenendigungen in den Epitlielien
hei den Wirbelthieren. Biol. Untersuch.. Stockholm, n. F.. Hd. iv (lHfl2),
S. ;57-44.— Kinigc IJeitriige ziir I\<'iintniss der intraeiiitholialen Endigungs-
weise der Ncrvcnfasern. Biol. Untersudi.. Stockholm (1894), n. F.. I'.d. vi,
S. 62-64.
361
1;'
,1
IB
U 1
i'7 ■
I'll' H
k
'i
1
i
'M
I
'.•■A
w
\■■^
/{
1"
l(
i
i^Hilli
WWi^
iM
302
TIIH XKKVOT'S SYSTEM.
tlio cpitlu'liiun liniii<j tli« urinary i)iis.sii<;('s, Tims, in the Iilad-
(Icr, for example, the sensory nerve libres run tan^eiitially for
long distances, making marked curves about the cells. The
— 1»
Fic;. :ill. — Nerve lilirils in tlic epitlii'lial liuiiiK of the (I'sopliafius ; iii('tln«l of
(idlffi. (After <i. Retziiis, Mini. I'liti rsiicli., St(i<kiiiiliii. n. !•'.. Hd. iv, 1S91>,
Taf. xiv, Kif,'. H.) <>, surfaee of epillielium ; Ixj, sul)ei)illielial eoiiUL'etivi)
tissue : II, nerve fil)re.
actual terminations, however, appear never to lie in the suiht-
ficial layers of the epithelium, but the briinches, htiving ptissed
out near the surfiice, turn backward to end free netir the jun<!-
tion of tlie epithelium with its connective-tissue support (Kig.
;il2). Whether or not this behavior depends ujjon the varia-
tions in the distention of the bladder wall, or represents a
mechanism for the purpose of avoiding a possible luirmful in-
tltience of the urine upon the nerve endings, is not known.
The mucous membranes covered by ciliated epithelium also
receive nerve fibres which end free in among and upon the
cells (Fig. ^i:}).
The number of nerve fil)rils present in ordinary epithelial
surfaces is remarkable ; even the gold method, by uu'ans of
which Cohnheim * discovered tiie free intercellular endings in
* Cohnlicim, .1. l'el)i>r die Eiidi^ijtinj; tier sonsiblon Ncrven in dei' llorii-
haiit. .\rcli. f. imth. Anut., etc., IJorl.. Htl. xxxviii (1867), S. 343-386.
(JitOUlMNO AND ('IIAI\I\(S 'nxJKTIIKIi OF NKI'IION'KS. 3(53
the cpitlidiiil liiytT of tlic conicii ( Kii;. "^14), shows in success-
ful prcpiinitious ii largo nunil)er of tine librils. liul the iiiffro-
/{
Fio. 212. — Ni'i'vi^ lilti'ils in tlu' ci*!!!!!'!!!!!!) of ii vcrticiil sccticin of tlic i'iil)l)it's
lihidtltr. Method of (IoIkI. ( After (i. Hctzius, IJiol. riileisiieli.. StocUlioliii,
11. v., 15(1. iv, 1S1I2, T !'. xiv, Fifi. 1. 1 o, Mipi rticiiil layei' of epilliiliiil ctlls;
/(;/. siiliepillii'liiil cimiicctive tissue; », nerve tilire passing from connective
tissue into tlu' epitlieliuui.
ill!
€.
t
J I
«i#iw MM?
Fm. 213.— Tenninatioii in tlie form of trefoil end iilatelets on the ciliated cells of
tlu' frog's palate. .SiKittal section; vital staining' witli methyW'ne lilue ;
alum coeliineal used as a eounterstain. ( .Vfler .V. Hetlie, ,\reli. f. niikr.
Anat., Honu, Hd. .\liv, 1S!)4, Taf. xii, Fig. t>. i
t
. t
■:p:
Fk;. ^15. Tninsvcrsc sec-
tion tlin)ii<;li the skin (if
tile cur of a wliitc
iniuisc three (lays old.
(After A. van (ielmcli-
ten, ('clliile, Licrre et
I.ouvain. t. i.\, IHiCi, fasc.
2, pi. i, Fi};. 1. ) /». nerve
tibrils; h, bifurcation; </,
hurizunt4il fibres.
UllOL'PlNa AND ("llAININ(i T()(iHTIIHIt OF XHUUON'KS. .^r.S
t^'uw and sjifraniiic staiiiiuj; of Macalliitn,* and the UK'tliod of
(lol^ji applit'd by I"'. K. Scliulzc,t van (li'liiicliti'ii,J and ollicrs,
has sliown us the roally enormous luiinhcr of nerve fibrils
tliat aro present in sueh structures (Fig. '^lA). The nietlu)d
of Kiirlich, applied to the skin and mucous mendirane by
KlxTth, Szymonowicz, ** lietlie, Do^Mcl (Fi^'s. '^Mti-'^MS), and
others, has revealed even more, it would appear that almost
every epithelial eell stuiids in ecmtaet relation with one or more
nerve fibrils. And perhaps this may be trui- of all epithelial
cells.
While the majority of tlu' til)rils in the skin and in the epi-
thelium of the mu(!ous membranes end free, often with fornui-
tioii of slit^ht vari('ositie.s, otliers of them termiiuitc in definitely
ditTereiitiated end platelets. As an example of these may be
mentioned the so-called trefoil-shajied platelets wliich Bethe||
has described as oecurrinj^ on the nerve librils in contact with
the cylindrical cells in the e])ithelium of the frog's tongue and
palate, uiul the round end plates whi(di he finds on the rod
cells, the forked cells, and tlu' dee|) cylindrical cells in the same
organ. These end plates (Fig. '^l!)) are to be looked u}»on as
expansions of the distal end of the nerve fdjril. The lu-rve fibril
is attached to the end plate very much as the stem is to a leaf.
Several of them may belong to a single nerve fibril, and, what is
more important, the same nerve fibre can ])e connected with
the simple free nerve endings as well as with these endings in
platelets. The epithelial cells in contact with these platelets
can oftt'ii l)e differentiated from the other epithelial cells hy
tlu'ir behavior toward alum cochineal. Xienuick describes in
the frog's tongue c;ells almost completely surrounded by a
mantle of nerve substance arising as an expansion of a terminal
* ;Miiciilliiin. A. M. Tlic Nerve Teriniiiiitii)iis in the Cutaneous Kpitlie-
liuni of the Tiuliiole. t^uart. .1. >rif'r. Sc, I.ond,, n. s.. vol. xxvi. pp. Tjli-TO.
+ Seiiuize. F. K. I<'reie Nerveueiideu in der Kpiderniis der Knoehenfischo.
Sitziiiii,'sb. d. k. Preuss. Akiid. d. Wissensch., phys.-inatli. ("1.(1802), No. viii,
S. 87, 88.
X vim Gchiichteii. A. I^es (enninaisons nerveusos intrn-epiderinir|ucs
chez quel(|ues inamniiferos. Cellule, liierre et Jjouvain, t. ix (18!):i), fasc. 2,
pp. ;i01-381.
* Szymonowicz, \V. Heitriifxi' zur Kenntniss der Nervenendipungeii in
ilauf,!j:el)ilden. Areli. f. inikr. Anat., Bonn, Hd. xlv (180.1). S. ()24-f)r)4.
II IJethe, A. Die Xervenendigunfjen ini (iaunieii und in der '/auv^o des
Frosc'hes. Arcli. f. mikr. Anat., Bonn, lid. xliv (1804), S. 185-20G.
.41
t!
18? Hill
;{«!('. TIIK NKUVors SYSTKM.
(ilM'il ; Hftlu' coiilil not, lidwcvcr, tiiid such structiircH in tis8iu>a
lixcd l)V liis inctlKul.
m ^ &r
Fi(i. tJKl.— Nerves iiiiil nerve eiuliiins lYoiii the liiiinan ('(inieii. ( AfttT A. S. DoKiel,
An.il. All/,., .leliii. liil. V, 1S!I0, S. ISS, Ki«. 5. ) .(, iiiediillMteil nerve tilire
wliieli (liviiles iiiln two. (/miuI c, oI' wliicli one, i', e'lils in :i ('(iiii|miiiii<I skein,
/)' : I he 111 her, (/, I iicmUs 11)1 into til rei' lininelies. /'.,/", /". The hni lie h y'cliv ides
into two thre;iiN, /( and / ; the thread /( ends in a lonp, />, and in a liiiokh'l,
A', hut the thread / h(d|is ti> Inriii the siiii]de skein ('; the hniindi 7' enters
tile eoinidex skein, H \ tlie hnmeli /'" tiiially lireaks np into the threads/'"
lind /"", ot" which the I'onner ends in a loop, /', whde tiie other j;oes into tlie
skein C. The liraiudi ./'" is siirromnh-d for a ei'rtain distance hy i.iyelin ; nu-
clei are, liowevr, iinniedialely adjacent to the tliveads f" and )'"". (i.
bniiieh ofa niediillated tihre (not shown in the tij;iire) wiiich hrciks up into
threads wliicli ;,'o over into the coinpouud skein, /( ; «, eenlial lihri' ; /(, peri-
plieral part ot'axoiie: c, myelin.
AnotluM' form of end platelet with wliieh liistolojrists have
heeome familiar since Merkel's * descriptions is tliiit to be met
* Merkol. Fr. Uobor die Eiidiijunfj dor seiisiblon Xervcn in dcr Ilnut.
Naehr. v. d. k. Gpsollsch. der Wis.senseii. n, d, (ieorg-Ang.-rniv.. Oottiiigcn
(1875). S. l'J;?-l'2S.— Tastzolleii iiiid Tastkorpen lien lie! den Ilaiislliiereii mid
bciiii :\Ieii.selieii. Airh. f. iiiikr. Anal.. Umiii. lid. xi (If^T.")). S. (;;!(i-().V2.—
Ueber die Endifjiiiifjen "tr sensiblen Ncrven in der Ihiut der W'irboltiere.
4to. Rostock (1880).
•!«4'li
(IHOinMNCl AN'I) CIIAININU TOCJKTIIKU Ol'' NKUUONKS. 3(57
with luljiKcnt to the well-known Taslvlhn of this author.
Till' I'pitlu'liiil cell {'la fit ■.vile ol" Merkel) iidjiicelit to the tiKV
tiU' mciiiseuH is ol" dilTerciit ulmpc, and posseHses entirely dif-
ferent Ktuinin}; reactions from those of the other cells, go
that wheji one is once fiiniiliiir with its ap|teariin(H' he can recv
of^'nize it in sections which liavc! not heen stained especially <•»
show the nervo endings. In tho skin, Merkcl's TantzcHi n are
Kid. 217. — Verves and tierve eiidiiisrs in hnnmn (ornea. (After .\. S. DoKiel,
Anat. .\nz.. Jena, lid. v. ISild, I'ifj. H. ) .1 ar.d /.'. two niediillated tilires,
each id' wliicli divides l'iirl<lii<e into two bniiielies 1 n, h and c, (I < ; (lie liiiiiieli,
(I, I'orins a siin|de sicein. tlie ntliers I'urni eipni|Miiiii(l siieins ; c. a varicose llinad
wliieli unites two end sl<eins : /'. tiireads wliieli liave arisen liy divisiiiii ol
tile a.xone of tlie niedullated lilires.
V. Sill
, i» '• <t •
p.
1
'.1
3
/I
^ss^\
most numerous in the interpapilliiry processes of epithelium.
They are easily denionstrahle ia the adult (Fi^. !i'M)) and
embryo (Fig. 221) pig by means of the vital staining with
: 11
11
, (I
368
THE NEIlVOrS SYSTEM.
mim
IllifP
i ni\
nu'tlivi('iu'-bhu>, as Szynionowicz; * has sli(»wn. I liavo staiiiod
tlu'iii liy tlu' samo nu'tliod in tlio pijjf's snout, and also in liunian
skin obtained from the surj^ncal operating room. W itli the aid
of Ik'the's fixing method one can obtain beautiful pictures l)y
counter-staining tlie sections with Czokor's alum cochineal. In
a succ- isl'ul preparation the expansions of the ends of the nerve
llbrils — the tactile menisci — are stained deep blue, the 'J'a.s/-
zi'llcn kj2 Merkel dark red, and other epithelial cells pale pink.
F!(i. ~MS. — Mcdullatcil iicrvc li^rc from the cimjiiiictiv:! of iiiiiii. ( After A. S.
DoKicl. Arch. f. niikr. Aiiat.. Uoiiii, Hd. xliv, isiM-'li.'), 'I'iif. iii, Kifi. o. ' 'I'lw
iiR'iliillatt'd til)rf ia) breaks up into single liraiielies ih) and smaller divisions
still (<•). which form a idt'xus beneath the epitheliiiin.
Merkel tliought at first that the Tdntzrllcii were actually gan-
glion cells. Now we know them to be simply modified epithelial
cells in contact with .special disklike expansions of the nerv(?
fibrils. The stiuctnios have been aptly compared to an acorn,
the ditrerentiated cell cGrres])onding to the nut, the meniscus
to the cup in which thy nut ^its, and the nerve filiril to the
stem of tilt: cup. Kallius looks upon Hethe's end i^latelets, de-
scribed above, as transition forms between the simple free inter-
♦ Szyinonowicz, W. Reitriigo zur Kpiintniss dor Nerveiu'tnli{?unj;en in
Hiiulfjehilden. Uebcr Han and Kntwiekelung dor \erveneii(li<;un,i;t'ii in
(ler SciiniiuzL' lies Scliwoiues. Areii. f. inikr. Anal., Bonn. Hil. xlv (I^i>5), t^.
0:24-635.
1
GROUPING AND CllAININO TOOKTllER OF NHUIioNES. ;5«;«)
colluliir iiorvc oiidings unil tlio eiuliug in inciiisci on Morkcrs
Til.shrl /{')/.
A coTiipn^lunisivc si'rii's of rosi'iircht's on I lie fio-cjillcd (iraii-
dry's* corpuscUis, which arc fouud in tho duclv's bill (Fig. 2'22),
^^M^m
Fio. 21!).— NtTVc cii(lin«s ill cpitlicliuni of froR's palate, i .Xf'tcr .\. Hctlic, .\rcli.
r. iiiikr. .\iiat.. Uomi. 15(1. .\liv, 1S!U 'iC), Tiif. .\ii. KiK>. •„'.:?, and I. ) Vital
staining with niclli.vlfiii' hiuc Fi.\ali<iii liy {{cllii's iiiclluicl; comitt rstaiii-
iiiK witli aliiiii ciM'liiiual. '(, two <'iuliii;;s with in toil ciiil plates, eiie nl' tla*
eli(liiit;s hei lit; seen tniiii the side ; h, upper Ixinler iif a sensory hiihieti teased
out (il'a saKiltal sertioti, nerve endings wilii treliiil plate mi lour eylindrieai
eells (line nl llieni seen iVmn tlie side, also nerve termination in tlie
torin III' a riiiiiid plate iin a nilind eell and nii one e.vlindrical cell in the
ih'iitli ; c, two isolated rod cells with end plates and nerve llhrils liniii a
teased preparation.
«» vHi
Fi(i
120.
Fio. 221.
.\ perpendicular section of thi' lower liart of the epideiiiiis lietweeii
two papilla' which shows a laifje iirmip of Merkel's 't'(i.it::fUfii. .\liove, oiii!
sees the liniits of the epithelial cells indicated, lielow two nerve lilires enter-
ill},' the epithelium. < hi the left side iirohalily a part of an end lnilli. ( .Viler
W. S/.yinoiiiiwic/,, .\rch. f. mikr. .Vnat.. Bonn. ltd. xlv. IsiCi, Taf. .xxxiii,
Kif,'. t) ")
I'k;. 221. — .\ periieiidicnlar section tliroiij.'h the lower jiart of tlic epidenids
hetweeii two papilhe. from a fietiis 30 cm. loni;, lo show the development of
the nerve eiidini;s alioiit Merkel's T(isl:cllni. i .Vfler W, Sz.vmonowii/. .\rch.
f. iidkr. Aiiat., Honn, l!d. xlv, Issri, Taf. .xxxiii. Via. '.).)
* firandry. TJeclierehci sur les corpuscles tie Piieiiii. J. de riiiiHl. et
physiol., etc., Tiir. (IHG'J).
t
1i
1
870
THE NKKVOrs SYSTEM.
niiiko it appear that tliose structures also represent groups of
epithelial cu'lls l)et\veen which nerve fibrils end free by means of
terminal end plates. Dogiel * has studied them with the me-
thylene-blue method and has convinced himself that there
are t'isks inside them which are (continuous with nerve fibres
lying between the cells of the corpuscle. The finer struc-
ture has been studied also by (ieberg f with both (Jolgi's
method and the methylene-blue stain (Fig. 22'.i). (ieberg be-
lieves that the nerve fibre breaks up in the disk into a number
of very fine fibrils which run in directions through the disk
Fig. 222. — Gniiulry's torininal nerve corpuscli's from tlu- <lu<-k's l)ill. (After M.
(inindry, .1. dc I'iitmt. et iiliysidl., I'm-., t. vi, lH(i!», jil. xv. Fi^. tO. )
(Fig. 224), while Dogiel thinks that the axis cylinder breaks up
into two bundles of fibres which run around the border in a
ringlike way, leaving the centre of the disk free from actual
nerve fibrils. It is rather interesting to note that (Irandry's
corpuscles are classed among the epithelial stru(!tures, despite
the fact that they are situated in the sube])ithelial tissues and
are inclosed in a definite connective-tissue sheath. The study
of the ontogeny of the cells, however, is said to have established
their epithelial origin.
The nerve endings in the hairs have naturally attracted a
great deal of attention inasmuch as these structures have long
been known to be very delicately responsive tactile organs. As
* Dogiel, A. S. Die XerveneiKlifrungoii in Tnstkiirpercheii. Arch. f.
Anat. u Physiol.. Aiiat.. Ahtii.. Leipz., Jahrg. (1801). S. 1H2-192.
+ (ielierg. A. UelxT die liiiiervntioii iler (Jaiiinenhaut tiei Sehwimm-
vogelii. Inlernat. iMonatschr. f. Auat. u. Physiol., Leipz., Bd. x (181)^), S.
205-240.
o - i - 2
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B
;>,72 THE NEl{ VOL'S SYSTEM.
von Frey * puts it, "• Every hair is a lever whose sliort arm is in
the sl\iii, wiiile the long arm serves for the recieption of the
i -
A B
Fm. 224.— Tactile tliscs from two (tninilry's corpuscles in ccpiiiieetiou with the
axis cylinders (/n/)of the nerve fibres connected with them. Methylene-
lillle stainini;. ( .Vl'ler .V. (le)perj,', Inlernal. Monatssclir. C. .\nat. n. I'liysiol.,
l.eip/., l'>d. X. ISiCJ, Taf. ix, l''i>;s ti and (>/;.) t die sees the axis cylinders jjo
over into thi' tactile disc, where the stained tihrils or lin miles of lihrils of I he
axis cylinder hreak up into delicate threads whi<h pass in dill'ereiit direc-
tions, lait mainly to the lionler of the terminal disc. In .V, a net work like
union of the threads can he made ont amonj; the lilirils of the tactile disc in
places, althoii;;h it is not ver.v niarked ; k, nucleus of the conuective-t issuer
.sheath of the corpuside.
^#'
l'i(i. 3'>.').— Xervo endings about a larcre hair from tlio dosr. fAfter T?. nonnet,
Alorpbol. .labrb.. Leip/.. ltd. iv. 1.S7S. Taf. x vii. Fij;. 1. ) <iold prepaiation.
The entering nerves partl.v form loo))s. which often k''o\v smldenly mrire
delicate, as at (( ; at '< one can make out the orifiin of the straight terminal
fibres KoiuK forklike from the nu'dullated fibres; c, circular terminal fibres
practiciilly in cross .section, visible external to the straiftht fibres.
* von Frey, ^f. Beitriiijp zur Physioloirio des Schiuerzsirmos. T5er. il.
niatli-])liys. TI. der K. Siiclis. ricsellisi'li. il. Wis.seiiseh., Leii)Z., Silz. voin 2.
Juli, 1804, S. 188.
^
^-
1
C V '-^
/
i
I
Fl(i. 'J:iti. — Krcclilc liody of ii liair of tlic rat. (After R. Pionnft. Mnrphol.
.liilirli., Lcip/... I'.il. iv. 1S7S, 'Piif. xix, Fij;. I!?.) (iolil i)r(]iMiatiiiii. /'.deep
layer of llie iiitraf(illi<iilar plexus: ll'd. swelliim "ii rodt slieatli slmwiiiK
nerve end Imds ; n, ])e<iiliar .ja^jied nerve terminals in llie ileep-lyiiif; nerve
plexuses; .V. liranili of entaneons nerve wliieli fcirnis the jilexus of the
neck of the hair follicle. // /', and the uerv4> rin>;, ,V /i' : I' S, circular sinus;
N/', siiouKy l)ody ; r, circular ridye ; M. muscdeof the f(dliide ; /•', fat.
^
lilt'
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1
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8T4
THE NHItV'OUS SYSTKM.
stimulus." The ciirlU'i' studies of liouuot,* M('rl\('l,t and
Arustcin J showed tlu; intiiuute relation of rnedullated nerve
fibres to the hairs, and indeed to a particular part of the huir
(Fi^a. 22^1, 2'ii'>). dust below the spot where the sebaceous ^hnu\
opens into it the hair foUiele shows a furrow about it, beneath
wlii(di is a jjrojec^ting rid<,'e. The nerves conneeted with the
hair folli(de approach this ridge and penetrate the sheatii, los-
ing on entran(!e their nuuluUated coverings. The further fate
of the nerve rd)rils was for some time not clear, though lionnet
by means of chloride of gold staining showed the existence of
lutrizontal branches running al)out the hair. These branches
gave (df asceiuling twigs which api)eared to lie upon the glassy
mendtrane of the hair follicle imbedded in longitudinal folds
in this structure. There seemed to be some doubt whether or
not the fibn^s went through the glassy nu'inbraue ; many be-
lieved that they did not perforate it but simply lay upon it.
The method of (iolgi in the hands of van (Jeluuditen* and
Ketzius II has shown the general characteristics of the endings
about the hairs in the mouse, rat, and man very clearly ami sat-
isfactorily (Fig. '2'i'i). In the mouse and rat ea(di hair receives
one nerve fibre which has its origin not in the deep nerves of
the skin, but as a branch of a neigldxu'ing fibre which is des-
tined to innervate also a portion of the epidermis. This fact
is of great interest inasmuch as it proves that either the hairs
and these portions of the epidermis have to do with the origin
of the same quality of sensations, or if they mediate different
sense-modalities then the same neurone must be capable of
transmitting from the periphery to the centres impulses con-
* IJoiinet, H. Studien ueber die Innervation der IlaMrbiiige der Ilaus-
tiiiero. Morphol. Jain-b., Leipz., lid. iv (1878). S. yj!)-:i!)8.
f Morkt'l, l''r. 'i'astzc'llcii uiul '{'astki'lrpcrclu'ii l)oi di'ii Ilaustiereii uiid
beiiii .Meiisclieii. .Vrcii. f. iiiikr. Aiiat., iJoiiii, I5d. xi (187(5).
t Ariisti'iii, (". Die Nerven der beliaarteii Ilaiit. Sitzunysb. d. k. Akail.
d. Wisseiiscli. Malii.-naturw. CI., Wieii, III. AhU, Oktober. 187(5.
* \'an (Jeliuehleii, A. Les iierfs des polls. IJull. Aead. roy. de se. di'
Bel-,'.. Unix., :5 s., t. xxv (18!):!), pp. •2;JO-'.2;i2.— bes nerfs des jioiis. Mem. do
I'Aead. roy. de Helj;., Unix., t. xlix. 18!»:i. — Cdiitributioiis a IVtiide de I'iii-
nervatioii des polls. Aiiat. Aiiz., Jena, lUl. vli (1892), S. 341-;M8.
II Ketzius, (i. I'eljer die Xervoiieiidijjiiii^^eii an den llaai-eii. lilol.
Unlersiieli., Stoeklinjin. ii. F.. I$d. iv(18!)2). S. 45-48.— I'eber die Kiidi^'iinj;s-
weise der Nerven an den Ilaaren des ]\b'nselien. Hiol. I'litersiieli.. Stoek-
holni, n. F., lid. vi, S. (51-02.
lUh.
<:: 1
'ill
(IROrPINO AND niAININO TOOKTIFKR OP NEURONES. 375
cernod in the production of more tlian one sense-riuality. The
nerve fibre liuving reached the hah- fulli(de, divides into two
brunches whicli run horizontally about the hair almost at riglit
angles to its course, one division running in front, the otlier
behind the hair. Tliese may meet or they may run only part
Hi.
Fi(i. 227. — Nerves and lU'i'vc t'luliiifis in tlie skin and liair follicles. (After G.
Ketzius, Hiol. rntersucli.. Stncklidlni. Hd. iv. isi);>, Taf. xv. Fiji. 4. ' list.
stnitiiin riirneuni: (//i, stratum Kerininativmii MalpiKliii : c. nuist supcilicial
nervc-tibre plexus in the cutis: », ciitancmis ncivc ; is, inner rout slieatli nf
hair: iis. outer root sheath ; /(. the hair itsi'lf: tir. fjlandiihe seliacea-.
Mi:'
of the way around, thixa forming an incomplete ring. Snuill
ascending twigs run up from these horizontal briinches parallel
to the dii'ection of the Iniir to terminate, according to van Ge-
1 M| :| ^
1 1'
.•{T<!
TIIK NK1{ vol's SYSTKM.
liin'htt'U, ill small cud nodules. A lew briiiiolics niii itfrpt'ii-
dinilarly downward. Rctziiis, liy means of (ioliri's inetliod,
lias made out very similar relations in the liumaii eml)rv().
^^^s
FlO. 228. Ki([. 22!). '■"•V*=^ "^^ "
Fl(i. 22S. — Xcrvc ciidilifis ill till' roriii of tactilf discs liciu';itli llu' jr'iissy iiicm-
Imiiii' iif till' iiiiirs. (Al'tcr V. (1st ihuiikiw. AiimI. An/,.. .Iciia, lid. x. ISlCi. S.
7.*^:^, i'"iKs. 2 :iii<l I. ) A. TiK'lili' discs liciiciilli I lie fihissy iiiciulniinc of a cat's
iiair. 'I'lic tactile discs arc coniicclcd with pcit'inaliiiu iicrvc lll)fcsaiid with
one anotlii T. Teased iirc|(aiatiiiii. I!. Neive endiii<;s ol' the hail' of a jiiji.
(I, tactile discs luneatli the f;lassy nieinl>iaiie : h. sIniiKht terminal lilires
external to the jilassy inenihrane which inn uiit into s|Hiiin-sha|)cd nr liatcliet-
shapcd endinus.
Flo. 2211. — i.iinniliidiiial view of tooth of (ioliins. sliowiii^ nerve terminals.
l.M'ter <i. ivetziiis. Miolo!,'. rntcrsmdi.. Stockholm, ii. !•'., lid. iv, l.s<l2, Taf.
xvii. I'ij;. ". ) </. dentine ; ii. ner\c lihres asceiidinj,' close to inner smiace of
dentine and ending: free.
Whether or not tlie nerves found by (^rru * and by Ketzius in
the iiapilla' of the hair tietuiilly run into the follicle iind
correspond to constiint nerve endings in the iidnlt must iis yet
remain undecided.
* Orni, !•'. Till toriiiiiiiizioiie nervosa iiei jieli. Boll. 1!. accad. (H Koinii,
Anno xix (1892-1893), F.sc. 7, i-j). T(i-J-TC7.
(i|{<»riMN(} AND CIIAININMI TocJKTIIKIt (tK N'Kl'UONHS. .'{VJ
Very (^onipliciitcd nerve eiuliii^s have l)eeii (ij'S(Til)e(l on tlio
80-ciille(l sinus Imirs by a number of observers. The most eom-
plete (h'scripi ion is that of Ostrouinow,* wlio worked with
meti)ylene blue (Fiji. 'i'iX). I have found in the eiiil)ryo p'l^r hy
means of tiie nietbyh'nc^blue tnetliod luTve endiiif^s connected
with (h'tiniti' Tiixlzollvn (of M<'ri\cl) inside the hair follicles just
as Ostrouinow baa described them. The "nerve end buds"
pictured by Honnet in 1S7S are probably the same eiulings
about Tastzellcn (cf. V'\^. Ji^ii, vide siipni).
Viv,. ^':i(l. — Nerve eiidintts in the liver. (After I'. KonilUdW, Aliiit. .\iiz., .leiia,
l!(l. viii. \S\r,\. S. 7.'):{. Kin. ~. ) ". iixis eylilKlelultlie l>le.\Mse\teii(liii« lielweell
I lie riiws (if liver eeils :/(, liliriU wliicii I'uiiii a iictwink dver (lie eell.^ ; c, r(>w.s
(pf liver cells.
That the teeth are sensitive to touch, and more especially to
pain, is a matter of fieneral knowledfjje. It lias l>eeii disi)uted
whether or not besides the nerve endings in the i)ulp there
* Ostronmow. P. Die Xerveii der Siinishiinrp. iiiitgi'toilt v. I'rof. Ani-
stein. Anat. Aiiz., Jena, IW. x (W9'}). S. 781-790.
^^i|il1l
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:{78
TlIK NKIIVOUS SYSTKM.
,
won' jilso norv*' (iudnif^s in the Holid jjortioii of the tooth;
while soinc havo bt'lii'Vt'(l tiiiit the iii'rvt' fibrils cud only
unioii<,' tilt' liodics of tlio odoiilol)liists lit the pcriphory of
the pulp, others think that they may actually pciu'tratc the
dentine itself, inasmuch as it is known that if the j^utu he re-
Fl(i. :,';51. I'criaciiiciiis plexus [n) nf nerve fibrils in tlie |i;ineii'iis. (After K.
.Miillir. Anil. f. niil<r. An:it., Hcnin. lid. xl, l.'SiC,', Tiif. xxii, Fiy. 10.)
tracted tlie dentine is sensitive at the margin of the enamel.
Retzius * has applied Golgi's method to the teeth of many ani-
* Retzius, G. Zur Kenntiiit*s iler Nervenen<lifjiuiji;t'ii in den Ziilmen.
Kleinere Mittlieil.iius deni (i('l>ipte der Xerveniiistolni^ie. Hicl. rnti^rsucli.,
Stockluilin, 11. 1'.. 15d. iv (18!)'J), S. 05-(56. — Ueher die Xerveiieiidiguiijjeii in
tlen Zilhneii bei Aiiipliibien. Hiol. I'litorsuch., Stockliolm. ii. I"\. lid. v, .S.
40-41. — Zur Kenntniss der Kiuli,i!:uiii.;s\veise der Nerven in den Ziihneii der
Saiigetiere. Biol. Untersuuh., Stuekliulni, ii. F., Hd. vi, .S. 54.
(}R()n>r\(! AM) ('IIAI\I\(} TOCiKTIIKU (>F NliritONKS. ;{7«>
iiials, iiiid liiis siiccetMlod in stuiiiiiig tlie nerves (Ki;^. 2'V.i). lie
finds that the nerve fibres of the pulp brunch niunifoldly and
l'"l(i. 23'.J. — Ncrvi' rcllsMiid ncrvi' (iliri's in the villi iind aiiiniij; the Klaiicls of the
iiilcsliiHim ttiiiic ol' (lie miiii(';i-|)i>;. (At'lci- S. iJiiiii('ni y CmjhI, tai;cii Iriiiii
A. OpiHl's tcxt-l k. ) II, li, <\ il, pcfikaryiiiis nC (lillcrciil siiapi's aiiiidiH
kI:iii(ImIii' intcstiiiiilcs ( I-iclifrkiiclini ; c. /, pcrikiiryniis situated in tlif villi
intislinalcs; the plixiis I'driiicd liy their prdccsscs is sliowii.
nro distributed between the odontoblasts endinjj close or near
the inner surl'aee of the dentine. He was never able, however,
to follow nei've fibrils into the dentintil tubules. Sul)sequently
the subject has been submitted to especial research by Morfjen-
stern,* who has obttiined very reniarktible results. lie describes
different sorts of endinifs not oidy in the dentine itself ])ut also
even in the enamel. These fuulings have been disputed by
* Morjjcnsteni. M. Tehor das Vorltniumoii von Xcrvcii in den hartcii
ZMliiistibsian/eii. Deutsche Monalselir. I'. Zalinli.. Loipz.. .lalii's. x (1892). Okto-
ber, S. 4:i')-4:)T. — W'eileres iicIkm' ^'()l•k(>nun(■n von Xerveii in den liarton
Zaliiisul)staii/,en mid iielier einc Metliodo sie aufzufitidcii iiiid zu konser-
vipivn. Ibid., Jalii-g. xiii, S. 111-114.
<i
t H V
\
;{8(>
TIIK NKU'.OIS SYSTKM.
Kl(t. !j:iH. Ncrvi' ciHliiiKs ill the siiliviiry kIiiihIs. (After <i. Kct/iiis, IJiiil. I'lilcr-
Hllcli., ISIMI, lakcll I'l'iilll Kuillh'l-'s lc\l ImmiU. I /, /, scctiiilif, nl' Miilli ; //,
frcsfciit ; II. II, iicrvr lilircs.
Fi(
(Aft.i-
Flo. ■J3r>. — Ncrvi' t<riiiiii:ils ill Irnnsvcisc section nf Ilie tulmli seiiiinileri ol' tli'
r.lliliit. ((. hlii(pil-Ves>el. ( At'liT (i. Scl:ivilin», iViiin Ivillllier's text-lMiok. )
(i|{(»nMN<i A\l> ClIAININ'd T'KiKTHHIl oK NKrilONKS. ;{,sl
Urwc,'" who thinks (hat Morjicustcni liiul to th-iil \ulli jin-cipi-
tiitrrt in ihiMlfUlimil tiihulcrtuinl on the iirncti^HHis of iho (xhnito-
bliistrt. I'or thf prcHciit, then, we imist uwiiit piiticiitly tin;
rcHiilts of riirthri- rfsciircli in this (lircctldii.
Astolhc h('^imiiiij,'s of ci'iilripi'tjilly <oii(lii(tiiij,' lilirt's in
tht' or<,'iiiis of liypt»lthistic ori^'in, fxchisivf of (he niucourt nii'iii-
briuu's, compurativcly littlo is known. ('u(!i;uti f imd liurkh-y
Y k-' A"
%
4j.»»^
l''iu. 230. -Ntivc ciHliiics ill Uic. iniiiimmrv k'iokI. (Aflcr Dinitri.ji'Wski, Knsiiii,
ISlll'. )
have (U'scrihcd the nerve endin^^rs in tiie lun<i;, and Hcrkh'y J and
l\orolkow** iiiive foUowed tiio tine nerve lihrils througliout tlie
♦ 1{()S(', ('. rdicr (lie Xcrvcnciiiiijjiiiififcii in (icii Ziiliiicii. I)('iits('li('
Mdiiiitsclir. f. Zaliiili.. Ii('i|iz.. .lalll•;,^ xi. S. oN-GO.
t Cin'cati.d. Nt'i'vi del piiliiiniii. Notii pri'vciitiva. prcsoiitala nlla ifiilc
Acciul. <li M(>l"i;mi iicilii Scssionc ild l.T (iiMiimio, l.SHH. — Snpni 11 dislriliiii-
iiHMito i> la tcriiiiiiazioiH' delle lilirc iutvcc iwi |iiilinoiii della rana U'Iii|m)-
raria. liitcriiat. ^loiiatsclir. f. Aunt. u. I'liysi<il.. lioipz.. Hd. v (IHHH), S.
1!I4-'J()I5. — iiitdnio al iiiodo oiidc i iicrvi si distriluiiscono c ti'riniiiaiin iici
lioimuiii f lu'i inuscdii addominali del Trituii crislatus. Iiitcriiat. Minial-
.sfhr. f. Aiiat. ii. i'liysiol.. \.vi\y/... Hd. vi (18H))). .S. ;.>;57-',M!».
I {{crklcy, I!..I. Studies in llic liiver. InlrinNJc Nerves. Johns Hopkins
llosp. IJep., Hall. (1S!M).
*• Knrolkow, P. Teller die Nervenendigunyon in der Leber. Anat.
Anz., .lena. I?d. viii (IS!):]), S. 751-75;j.
4:
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;582
THE NEKVOl'S SYSTEM.
liver substfinco {Vig. 2.'50). The puncreas (Fig. 2'U) as well as
tlie stomach and intestine (Fig. '^^3:^) have been studied by
Erik Midler,* and liy Kamou y Cajal, and the salivary glands
(Fig. 'iXi) and the thyreoid have also been investigated by
several observers. The endings in tlie epididymis have been
studied by Timofeew (Fig. ^;{+), tliose in the testicle by Sela-
vuiios (Fig. •^;5o). Tlie sensory as well as the motor and secre-
tory nerve endings in the mammary gland (Fig. ^^J'l) have
->;;■'-
' •r'-'-'-'i*
6 ; c
Fid. 'i:X7. — Two I'orpnsclps coiitiniiiuj,' iicrv.' I'luliiiKs fnnii tin- external cen-
iiective-lissue slieiitli ef llie (Icp^'s indslate. (After Tiiniit'eew. ISil"). rnnii
Haulier's text-l)cMik. I it, thick iiiediillaled nerve tilire wliieli riiiis (iiil iiitu
til' liaiid-sliaped axis cylinder; It, delicate inediillaled nerve lilire wliicli
forms the t«'rniina! apparatus; iiietliyleiie-hlue stainiiif,'.
lately been studied by Dinitrijewski.f Two corpuscles from the
l>rostate are shown in Fig. "X'Xt. AVithout going into a detiiiled
description of the findings in these various orgtins it may be
stated that everyone has been surprised at their eiu)rmous ricli-
ness in nerve fibrils.
* J'iiller, E. Ziir Keiintniss der Aiishreitimg niul Eiuligurif^sweise der
Magcn-, Diinii- and Pankreasnerven. Arcli. f iiiikr. Anat., Bonn, M<1. xl, S.
31)0-409.
+ Dmitrijcwski, P. Ueher die Nin'v?ii des Milclidrliscn. Diss, Kiismi,
1H{)4. abstracted hy Stiedii in Merkul-Homiet's Ergebn. der Anat., lid. v
(lylir)), Wiesb., 1890.
i f!
CHAPTER XXXI.
TJIR MKOl'LLATKI) PEHII'II KKAL AXONKS OF TIFK PKUIPTTKRAL
CKNTUII'KTAL NKLKOXKS AXI) TIIICIU TKUMINAL Al'PAKA-
Tl'S — {('(nitiHIIl'd).
Sensory nerve begiimiiigs in niosohlastie tissues — ("oriiini and tela suheii-
tanea — TuniciP nuieosa' and tein; subinueosa' — Meninf^cs — Tendons —
Conneetive tissue of oriiaiis — \'()luntary, eardiac and sniootli muscle —
Nerve terminals in [lathologieal growths.
Sensory Nerve Beginnings in Mesoblastic Tissues.
Wk next have to consider the disti-ibution of tlie peripheral
extremities of tlie centripetal nerves in tlie various niesohlastic
structures inclu(lin<f the coriuni and tela suboutanea of the skin,
the connective tissue of mucous membnines, the meninges of
the brain, the tendinous structures of the body, the capsules
and interstitial coniu'ctive tissue of the solid organs, and the
muscles, including voluntary, cardiiic, and smooth muscular
tissue. Here also it has been found that the lu'rve fibrils nuiy
terminate as free endings either in the form of delicate viiricosi-
ties or end-platelets, or they niiiy be inclosed in encajisulated end-
organs of specific structure (corpuscula nervorum terminalia).
I'Ki. 2:{H.— Free nerve endinRS on tlie l)usal menihnnie at the Juiicticm of the
epiilerniis with the sulicutiineous tissue, i After W. SzynioiKiwic/.. Arcli. f.
niikr. Aniil., Pxniii, \U\. xlv. Tat', .\x.\iii. Fif;. .">. i One" sees a iutvc tilu'e
fiitfr iViiin liclow on each side and l)reaU up to tnrni an cud plexus, ."^zyumuo-
wic/. thiuUs that thiscudiuK is icU'Utiial with the tcriiiiiKiismi hi'dn-ii'ormr nl'
Kauvier.
In tlie skin tit the junction of the corium with Uie epidermis
itiinvier has described whtit he calls frnnitHiisons hi'di'rifoniirs.
'riiese have subse(|ueiitly been studied by tlie methvlene-blue
method by Szymonowicz * in the snout of the pig ( Fig. :i'.\H).
Op. cit.
383
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384
THE NERVOUS SYSTEM.
They consist of axis cylindors which divide manifoldly and
form irro|jjuhir dendritic end-])ranciiings and end-pU'xuscs, the
fibres often showinj^ varicosities in their course. According to
Szymonowicz, they are more deveh)ped in the parts of the skin
in which Mcrkel's Tastzvllvn in the
epich'rmis are absent or present only
in small Tinmbers. They often lie im-
mediately upon the basal membrane,
following exactly the indentations and
irregularities of the junction of the
epidermis with the corium. Szynu)no-
wiez could not make out, however,
N that any branches ever passed into the
epidernus to run among the epithe-
lial cells.
The endings lyiug upon the glassy
membrane of the hair follicles also
represent free nerve endings in the
coniu'ctive tissue.
Of the special eiid-organs occurring
in the connective tissue of the skin
several interesting forms have been
described. First of all the tactile cor-
puscle described long ago by Wagner
and Meissner* is familiar to every one (Fig. 'i'-V,)). X section
made through the skin of the pulp of the finger shows numbers
of these in the papilhv of the corium. Sometimes the corpuscles
are simple, but they may consist of several lobules with a com-
mon base. One or more nerve fibres enter the lobule at or iu>ar
its base; after taking a somewhat tortuous course each plunges
into the corpuscle, loses its myelin sheath, and divides repeatedly
with forjiiation of a definite end arborization inside the corpus-
cle. Each termiiud branch runs out to end free, usually as a
* \Vay:npr, |{.. iiml 0. Moissiior. T'ohor dns VorlifuuliMisoin liislicr unlic-
knniitcr oif^ciitliiimliclicr 'J'iistkririicrclK'ii (Corpusfulu tiictus) in don (ii'fiilils-
wJirzc'lKMi dcr nuMischliclien Ilaut nnd ueber die Endausl)rcitung sensitivpr
XorviMi. Nadir, v. d. k. (iosi'llsch. d. Wissonsch. ii. d. Goorii-Aufj.-riiiv.
Gutting.. lHr)'2, S. 17-32. Also IMoissncr. (i. Heitriige zur Anatoniie iind
Phy.siologie dcr llaut. licipzig. 185:5. — /nr Lehre vom Tastsinn. Ztsehr. f.
rat. iiiod.. licidi'll).. n. F.. I5d. iv {\KA), S. 2(!()-'JH().— Untcrsiicliungen uebur
den Tustsiiui. Ibid., a K., Bd, vii (1«5!)), S. 02-118.
Bl
Ft(i. ;.'3!1.— Tactilo corpuscle
cil' Mci? ,ncr IVnin a section
tlinnifih the skin of the hu-
man toe. Fixation with os-
inica<'i<l. />'/. hi 1-vessel ;
A", incdnllated nerve fibre.
(After P. Schicirerdeck-
er, (iewehelehre, Hrann-
sclnvcij;, ISid, S. '.2^1. Fij;.
141.)
. 240. — Section tliroufih tI)o skin ciftlio tod. In tlirpt> pHpillii' Mcissnrr's cin--
imsiUs with stained nerve lihri". are visiMe <(, stratum heiiini'i ; h, stratiin
Ki'antiliisnni ; c, stnitiiin .Maliii«lii. (Alter .^ . S. I)ii«iel. InUrnat. -MonaLsseiir.
f. Anat. u. Physiol., lA-iv/.., m ix. IHUa, Tal'. v, Fi«. 1.;
Fio. 241. — M('is,sncr's corpuscle, a and a', axis cylinders of nerve fibres, which
enter the cori)nscle an<l hreak n|) into hnuiches and threads, out of which the
nerve skein arises. ( After A. S, Dofjiel. Internat. Monatssclir. f. Anat. u.
Physiol., Leipz., Bd. ix, 1892, Taf. v, Fig. 2.)
26
386
THE NERVOUS SYSTEM.
IIUhI
1
iiHtia^ni
1
somewhat flattened plate in among the flat or wedge-shaped cells
{KolbcnzcUen of Krause) * of the corpuscles. These corpuscles
of Meissner are abundant in non-hairy parts where tactile sense
is acute. They have been carefully studied by means of the
methylene-blue method by Dogiel.f lie has described at length
the formation of a system of loops resulting from the spiral-
like curvings, manifold divisions, and crossings of the fibres
inside the corpuscles (Figs. 240, 241). Dogi believes that a
network is formed of these divisions, a view shared by Smirnow,J
Flo. 242. — Tactilf corpuscli' from tlu' skin of the volar siirfaco of the index fluKcr
of a man twenty-iivc years old. Method of Uolfji. (After A. Sniirnow, In-
termit. Monatssehr. f. Anat. u. Pliysiol., Lt-ipz., Bd. x, 181(3, Taf. si, Fig. 5.)
who has studied Meissner's corpuscles in the skin with gold
chloride, with Golgi's method, and also with methylene blue in
* Krause, W. Die terminnleii Ki'jrperchen dcr einfach sensiblen Nerven.
Hanover, 8vo, 1860. — Die XerveiiendiKung in den Tatitk(irj)erclien. Arch,
f. mikr. Anat., Honn, Rd. xx (1881-"82), S. 212-221.
f Dojjiel, A. S. Die Nervenendigmifjen inTastk(ipcrehen. Arch. f. Anat.
II. Pliysiol.. Anat. Abth., T.eipz.. 1801. S. 181-192.— Die Nervenendigiingcii
in Meissner 'schen Tastkorperchen. Internat. Monatschr. f. Anat. ii. Physiol.,
Leip/.. Ud. ix (1892). S. 70-85.
X Stnirnow, A. Ueber EndkoUien in der Ilaiit der Planta pedis und
ueber die Nervenendifjuiifren in den Tastk<irperelien dcs ^lensclien. Internat.
Monatschr. f. Anat. u. Physiol., Loipz., Bd. x (1893), R. 241-247.
Fig. 243.— Poriplicral part of conjunctiva palpclmirnm of man. a. i)apilla with
terminal nerve corijuscle inside; /*. layer of epithelial cells on the surface of
papilla. Vital staininj; with methylene hlue. i After A. S. Dogiel, Arch. f.
niikr. Anat., Bonn, Hd. xliv, 1804-95, Taf. iii, Fig. 1.)
Fio. 214.— Terminal nerve corpuscles in the eyelids of man. 'After .\. S. PoRiel,
Arch. f. mikr. Anat., Bonn, Md. xliv, lS!t4-'iir), Taf iii, Fig.s. 2 and 4.) I.
Terminal nerv<' corpuscles from the papilla- of tlie margin of the lid ; a.
mednllated nerve (ihres. II. ,1,7/, ('. terminal nerve corpus<'les of ditferent
forms from tlie pars orhitalis conjunctiva'; n, the slu'ath ; h, nuclei of tlat
cells of the sheath ; c, mednllated nerve tihres.
,, 1 ■ I
I
i
i
*i
iti
'J
I
,»jl,
1
i
1
.
:-i jiH
:ini
ass
TIIH NKIiVors SVSTK.M.
perfectly fresh tissue removed at operation (Fig. 24'^). The
latter .staiiun<^ showed exquisitely the rainificutiou and division
of the fihres inside the corpuscles. Methylene-hlue preparations
Sp-
Sr M
on—
2a-—
ON-
w[i'!9m0'i\£^0^
ON--
za —
7^-
Fio. 245.- Sciiii-scliciiiiitic section of tlic skin of the pnl|i of the fini;( rs in order
to (leinon>tiate tlie toiM(j.'iii|ili.v of the "terniiniil nervous organs "( O.V )
(leserilied liy Kullini. i After A. KiiHini. Aieli. ilai. de liiol.. Turin, t. xxi.
1S!(4, pi. iii. Fin. V.i.' Cliloride-of-Kold preparation. At. arteriole; cV.
Meissner's eorpuseles ; rl'. tninsverse sections of Pacinian eoriiuseles; </.>.
sudoriparous j,'lanils : 0.\. Kullini's endinjjs ; >y), papillary layer of the skin ;
>')■, reticular layer of the skin : -.n. fat.
show that the same nerve fihre mtiy be connected Avith more
than one tactile corpuscle, and Dogiel stiites that he has seen
fi])res cjiter the corpuscle, pass again out of it, and enter the
epithelium to termiiuite there. End corpuscles (Figs. 24;{, 'H4)
!-*•■•. ^a(IW*«W*~~
l-v 11
GROUPING AND CHAINING TOGETIIKR OF NEURON KS. 389
Fl(i. 24fi.— Rnffini's nerve ciKlinss (nr-
(imifx iirnrii.r terniiiioiu). (Alter A.
UuHini. Areli. it;il. de l>iiil.. Turin, t.
xxi, ISiU. 1>1. i. Fifjs. 1 and 2.' Termi-
nal nerv(> eylinilers t'i)riiie(l of various
tilires eoniiii).' rmni the divisinn and
siilidivision of a siufrle nerve tilire ;
all. niveliu slieatli : ('. terminal inter-
laeinKs (if tile axis eylinder : /-. eoii-
nective-tissue slieatli.
,1)1
1 1
11
'li
:;!'
i:
I 'H-
¥i
390
THE NKUVOUS SYSTKM.
somowliiit similar to Mcissnor's rorpiisclos, but much simpler,
have lu'en described in the eoujuiietivii of Imiiuin l)eings by
Dogiel.*
A special variety of terminal corpuscle has been described
in the subcutaneous tissue of the human finger by RutTini.
These l)odies, wliich are oval in shape and about as numerous
as tile corpuscles of I'acini, lie at tlie junction of the corium
and tela subcutanea, and often, according to Kutllini,f in the
connective tissue septa which separate the nuisses of fat in the
latter (Fig. 24o). These corpuscles, which he mimes orf/diies
iicrrru.r frniiiiDii/.r, are ordinarily known in the bibliography as
i?
Fl(J. 347. — Tci'iiiiniil iicrvccorpuscli' of Kutliiii. Tlit' iicrvc (Dn'cs enter l).v one
of tlie extremities of tlie eorpusele. It is easy to nmke out tliiit Henle's
sheath Kcx't^ to form tlie eapsnle of tlie eorpusele. (After A. Hullini, Arch,
ital. lie l)iol., Turin, t. .\.\i, l,si»4, pi. 1, Via. t)
" Ruttini's endings." They receive their nerve fibres from the
side (Fig. ^-tO), or more rarely from one end (Fig. 247). The
nerve fibre, when once inside the strong connective-tissue
sheath, divides into numerous branches which show varicosities
* Dogiel, A. S. Die Xervcnemligungen ini LidraiHle nud in dor Con-
junctiva palpbr. des Mensciien. Arch. f. inikr Anat., Bonn, T?d. xiiv (1894-'95),
S. lu-a.!
f RnHiiii, A. Di un nuovo organo nervoso terniinale e sulla presenza del
irpusroli Golgi-Mazzoni ncl conncttivo .sottocutaneo doi polpastrell delle
uita deir uonio. Mem. d. R. accad. d. Lincei, Anno cci.\xxvii (189.3). — Sur
un nouvcl Organe nerveux terminal ot siir la presence des corpuscules Golgi-
Mazzoni dans le conjonctiv sous-cutane de la pulpe des doigts de riiomme.
Arch. ital. de biol., Turin, t. xxi (1894), pp. 249-265.
^' F"*
nr
OROUPING AND CHAINING TUGETUER OP NEL'KONES. 3<)1
in their course and end in small free end knobs. Huttini be-
lieves that they form actual anastomoses before terminating.
The Ruffini ending is seen in cross-section in Fig. 2-lH, and in
ncc
^^■•■11
Fig. 248. — Tnuisvcrsc section nf Iviilliiii's tcriniiial (•(irpiisclc. I After A. Ulitliiii,
Arch. ital. de biol., Turin, t. xxi, 18it4, pi. ii, Fij;. 12.)
il
ncc
il
t i
1
%
m
i
Fig, 249. — OtilifHK^ seetion of a terminal norvo conuiscle of Hiiflini. (After A,
Kuffini, Arch. ital. de hiol., Turin, t. xxi, 1804, Fig. 11.)
i^'
rr —
I
■'i\
^
^^H
'
3'J2
THK NERVOUS SYSTEM.
obli(|U(> section in Fij,'. •^4!). Ruflini's fmdinfjs liavo been con-
firnaMJ by Sfainoiii * and by von Frcy. That a numbt'r of (jiul-
FHi. '-50. — A nerve til>re is slmwii dividiiiK iiit" seven seeondiiry titires tii wliicli
are iittiielied tive iiniinir.i iiirmix lirniiiinii.r of Kiifl'uii. (AI'tiTA. Kulllni,
Ai-eli. itiil. de liidl., Turin, t. xxi, isiu, pi. ii, \'\>i. 10.)
iuffs may be attached to the subdivisions of one nerve fibre is
well shown in Fifj. 2f)(). These corpuscles of Ruttini while they
resemble the corpuscles of (Jolgi and Mazzoni, are really dif-
ferent from the latter.
A somewhat simpler structure than Meissner's corpuscles is
met with in the so-called end bulbs of Krause,f which occur in
the skin and in fjrcater numbers in the conjunctiva. Kach
corpuscle consists of a sheath made u]) of Hat connective-tissue
cells continuous with the perineurium inside which is the so-
called inner bulb, a finely granular mass which shows some-
times a concentric lamellation. In the centre of the inner
bulb is the axis cylinder, the myelin sheath having been lost at
its entrance into the organ. The axone ri;ns out to end (piite
free at the upper end of the bulb, usually terminating in a
slight button-shaped thickening. These structures have been
studied also by Szymonowicz with the methylene-blue method.
♦ Sfamcni, P. Recherches comparatives sur los orffancs nervcux terini-
naux lie Kiillini. Anat. Anz.. Jena. R<1. ix (1804). S. 671-6T6.
f Krauso. \V. Die terininalen Kcirperchcn der einfach sensiblen Nerven.
Hanover (186(»), Svo.
liir
GROUFINO AND CIIAININO TOdKTIIKU OP NEURONES. 3«J3
IliH Hiulings uru well illustriitcd in Fi}r. •v'Al. The ciKl-hulhs in
the conjuiictivji where Kniuse first discovered them have hoeii
descrihed by Doj^iel (Fiff. 'i^'^).
Not unlike these simple evlindrieal end-l)ull)H of Kriiuao,
and diireriuy fruni them in reality mainly in the comijlexity of
the eapsule, are the peculiar cor-
ptiseles variously known as the
corpuscles oi Vater, of Pacini,
and of Ilerbst.* Tiie <,'eiu'ral
apitcaniniHi of the Pacinian cor-
puscle from tho cat's mesentery
is well known (o every medical
student, since it forms a stamlard
K j;
.*. 1. I
■| i
Fl(i. 'jr)!. — Kiid liiillis slaiiuil liy tlii' iiU'tliylciic-Miic iiictlKid. (After W.
S/.yniiiiiipwic/., Arch, f, iiiikr. Aiiat.. I5imii. M. xlv, ISO"), Tat'. x.\.\iii, Mys. I
and ;{. I ((, .spirally twisted end Imlli ; t'le a.xis cylinder, the inner l>ull>, and
the connective-tissue layers can lie seen : the small piece on the rii;lit-hand
siile liehiw priilialily liehmtis tii a seciiiKl end liulli. h. terndnal <'iirpnscle com-
posed of .sever,! 1 end hnlhs.
^dy--^,,si~'-^^
Vlu. i'ri. — Terminal <'or])nsc1e from the cdfif of the con.innctiva hnlhi. (AftiT
A. S. Doffiei, .\rch. f. mikr. Anat., Honn, l?d. .xx.wii, ls!M. Taf. xxxiii. Viti.
3,) II. niednllated nerve (ilire, tiie axis cylinder of whicli Koes ovi-r into a
deii.se end skein.
object for study in every histological course. The corpuscle,
large enough to be visible to the naked eye, has a translucent
* Herbst. O. Die Paeiiiiseheii K()r|H'r iiml iliri' Hedeiitung. VA\i Beitnig
zur Kenntuiss der Nervenpriinitivfasern, Gottingen, 1848, 8vo.
ii
<■:'!
M -!
'6\)-k
TIIK NKUVOUS SYSTKM.
uppciinmce. Tlic fil)r()UH nhciitli of tlif iicrvo is continuous with
tlu' conni't'tivK-tissuc Hlioiith of tlio (•ori)UscU', tlu- latter con-
siHtinj,' of from twi'lvo to tifti-en or niorti coucontrio huucllu'.
Tho niyi'lin siiouth passi-s for Homo distance into the orpin, hut
as soon as the nerve lihre lias reached tlie inner hull) the myelin
sheath disappears and the axis cylinder runs naked in the centre
of the inner hull). At the apex of the hull) the nerve flhre
often divides into several processes, all of wliich run out to end
free in tho granular suhstanoo of the hull). Khrlicirs nu^thod
is very suitahle for the study of these structures, as Dogiel *
and Kalliusf have shown, inasmuch as the nerve lihre stains of
an intense hlue or purplish color, while the granular suhstance
of the inner hulh stains only feehly (Fig. '^r^'i). UetziusJ has
A
s*^^5?^'a?»>
H
Flo. SiiS.— II(>rl)st's rorimsclcs. >[ctlivlin('-l>lii(' stainiiiR. (After A. S. DoRicl,
Ai-ch. f. Aiiat. n. I'liysi..!., Liip/.. ls!»l, Aii;il. Al)lli.. Taf. \i. Via. H.l Tli(>
axis ('.vliiidcr I'lilrrint; llif <iir|piisclc A breaks lip iii^iiic I'"' iiuur luiDi into
tlircc liraiiclifs, racli of wliicli Icrminalcs in an ciiil kmili : in llic ciiriinscli' B
a side twij; is uivtii olV in tlic inner liulli iVdUi tlie main lilire, alsn terniinat-
in^ in an eml kncili.
' t ■ I
studied thorn also by using (lolgi's method. The surface of
the terminal fibre shows many black prickly jirojections. Sim-
ple treatment of I'acinian corpuscles with dilute icetic acid,
however, shows ])ractically all the details of the structure (Fig.
54). I'acinian corpuscles occur in the skin of human beings
in the connective tissue near joints, in periosteum, on ten-
dons, and in the connective tissue of the serous membranes,
pericardium, pleura, ami peritouieum.
* Dogiel, A. Die Ncrvenoiidipungcn in Tastkorpprchcn. Arch. f. Anat.
u. riiysiol.. Anat. Abth., Leipz.. Jaiirg. (1891), S. 181-192.
+ Op. cit.
X Uetzius, G. Die Pacinischen Kiirperelien in Golgischer Fiirbung.
Biol. Untcrsuch., Stocivholm. n. F.. Bil. vi (1894), S. 65.
<lIU)riMN(» AND CIIAININO TOOFyniKIl OK NKUKONKS.
.".95
Fio. 254. — Corpuscle of raciiii of tlif incsfiilvry of an ailiilt cat ; stiulicfl fresh
witlioiit addition <ifan,v rca^rciit. r. cai)siilcs; </. ciidolliclial rows scparatinn
tile corpusi'lcs ; ii, nerve filire leavini; cor|iuscle ; /'. perineunil slieatli ; in,
centnil mass or so-called inner l>nl
tenuinal tihre
point where one
of the hranehes of the terminal tilire dividi's into a lar^e nnniher of hranches
which tii> to form nnnieroiis terminal hul^'inj;
(After L. Kanvier. Ti-aite
1
«
Inl!
{
techniiiiie d" histologic, Paris, isT,'), p. <);.':5, Hk- :5"!'. )
31)()
THE NEIiVOUS SYSTEM.
M*
Rufliiii * (Icscrilx's ji modified form of Vater's corpiisclo in
dilTi'iTiit parts of the body, '.viiicli he desij^niates the 'Miolt^'i-
Mazzoiii eoi-])us(de." It is in reality the same corpuscle do-
scribed by (iol^'i ill tendons {ride infra). He finds that the
nerve filires inside these bodies divide ofteiicr than in typical
Pacinian corpuscles, alth()U<j:h they always end free in ilat bulb-
like expansions. Uutlini liiuls them not only on tendons liut in
the subcutaneous connective tissue of the fiufjer tii) (Kig. 'i^h).
It is evident that Krause's bulbs, the N'ater-I'aeinian corpuscles,
the tendon-cor])Uscle of (iolgi, the terminal corpuscle of
Mazzoni,t and thi' (Jolj^i-Mazzoni corpuscle of HutHni are close-
ly allied varieties of nerve endings. In tin- same grou}) are prob-
ably also to be placed some of the so-called genital corpuscles,!
They have been carefully studied with the methylene-bluo
method by Retzius.* The main ditference l)et\veen tiiem and
tlie Pacinian corpuscle lies in the fact that the genital corpuscle
has fewer lamelhe in its connective-tissue sheath {ride Pigs.
250-:;J5(S). These bodies have been studied in human beings
and in the mouse by Dogiel || (Pigs. •-J5!»-:i()I).
* Uufflni, A. Di una particolare retict'Ua nervosa e di aleuni corpuscoli
di'l Pacini die si trovano in conecssione coj^li orpmi nuiscolo tcniiiiici tlcl
pitto. Atti (1. r. Aecail. ti. liincel, An. (•clxxxix (1H92). Scrie II. Uondic.
CI. (li sc. fis.. mat. e nat.. Honia. vol. i. faso. 1:5, 1 Scniestr. (18!)2). pp. r)42-(i4<i.
— Sur iiM ivliciiu! ncrvciix s|i('cial et sur (|iu'i(|iics c'()r[iuscles tic Pacini (|iii
so tmiivcnt on coniii'xidn aver Ics orj^anps nuisciilo-tcndincux du chat.
Arch. itaj. dc Itiol., Turin, t. xviii (lH!t2). pji. 101-10").— Also, Sur mi nouvcl
orpane ncrvcux tiTininal ct sur la presonce dps corpusclos (iolgi-Mazzoni
dans If fonjonctiv sons-ooutam' do la pnlpc dcs doigts do riioninic. Arcli.
ital. dc l.ii.l., Turin, t. xxi (1S!»4), pp. 2-ia-!2«r).— Sopra dui spcciali modi d'in-
riorvazidiie dcifli orpani muscolo-tendinci di (Jolgi con riguardn spcciak" allit
stnittura del tcndinotto del orjraiio muscolo-teiidincocd alia nianicradi coin-
portarsi dcllc tiliro ncrvosc vasomotoria ncl jifrimisio del gatto. Monitore
zool. ital.. Fircnzo, vol. viii (1H»7). pp. 101-105.
t Mazzoni. (isscrvuzioni microseopiclio sopra i eosidotti corpuscoli tor-
niinali dci tcndini dell" uomo c sopra alcuno particolari )iiaslre nervoso
supcrficiali clic si trovano noi incdisiini tcndini. Mem. Accad. d. se. d. 1st.
di noiogna. S. 6. vol. 1 (IHill).
X Wdlhistl^i'iriieirhfii of the Germans.
* Hetzius. (r. Pcber die Endigungsweise dor Nerven in den (Jonital-
nervenkorperclien der Kaninclieu. Internat. Monatschr. f. Anat. u. Pliysiul.,
Leipz.. I?d. vii (!M!io), s. ;«:!-:!:!;{.
II Dogiel. \. S. Die Xerveiiendigungen in der Ilaut der aeiisseren
{tonilalortram- des Mcnsdien. Arch. f. mikr. Anat., Bonn, I5d. xli (1893),
S. 5H8-(irJ.
OllOUl'INCl AN'l) CIIAININU TOdETllHU oV NHL'UONES.
397
iiilli
•'«!
i
■J
,1
. iili:.
■h ii
I';
'V
1
^ 1
l,i..l., Turin, t. xxi, 1H!.I. pi. iii, Fitis. 14. 1... unci U..)
:y|
ililli.'
398
THE NERVOUS SYSTEM.
Fig. a.W. — (icnitiil nerve eorpuseles from the miieniis memlirsine of the elitoris of
thenililiil. Methylene-blue stainiiit;. (After (i. Ret/.iiis, Interiiat. Mouatsschr.
f. Anat. u. Physiol., l.eipz.. M. vii, 18i»0, Taf. xiv, Fifjs. 1 and 2.)
GROUPING AND CHAINING TOGETHER OF NEURONES. 3y«>
Fio. 257. — ftptiital nerve corpuscles from the mucous meinbmne of the glsins
I)eiiis of the nihl>it. MetliyU'iie-hlue stiliuin^. (After (1. Uetzius, Interuat..
Monatsschr. f Aunt. u. Physiol., Leipz., Bd. vii, 1890, Taf. xv. Fig. 15.)
nil
1^
■un
AH
1
1 /
Fi(i. 2.'JH. — Cross section of fienita! nerve corpuscle from the clitoris of the nihhit.
Fixation witii Fleiuniinfi's Huid : hieniatoxyiin staining. ( After (}. Ketzius,
luternat. Monats,schr. f Anat. u. Physiol., Leip/,., Htl. vii, ISiid. Taf xv,
Fiji. Hi. )
Ui
I
■^
iS^ti
400
TlIK NKHVOUS SYSTKM.
A pcouliiir form of iiorvo otidin^ liitlicrto undcscriluMl has
bci'ii found by Dogiol * in tlu' coniu'i-tivc tissue! of the coriu'ji.
lie has made out in this situation peculiar free terminals in
the form of definite end-plateh'ts. He describes nerve Itranehes
which ru!i more or less parallel to the marfxin of the cornea,
sometimes in radial directions toward the centre of tliis struc-
ture. At their extremities are found Hat (piadrangular or
Fio. 250. — frpiiitiil iicrv<' corpiiscli's frmn liiiinaii tiliiiis penis. <i. sliciitli of n
nerve stem ; /). siiealli nl' corimscle with iiiicUi of tial cells in s;mn' ; c, iixis
fvlinilei'soi" nerve (ihres wiiieii liraneli insiiie I lie inner luilli of the eorpiiscle.
(After \. S. Dofjiel, Arch. f. niikr. Anat., Honn, Hd. xli, \HW.i. Tat', x.wii,
Fijjs. 2 and 3. )
irrefjuliirly rounded end-platelets, some of which show concav-
ities and iudentiitions, with uneven tind ja<(f;ed borders (Fig.
2()2). The size of the individual pltiti'lcts varies much. They
never conttiin nuclei, and they sometimes resemble closely the
corneal cells, but in reality have no connection with the latter.
It is not impossible, as Kallius points out, that the older idetis
of Kiihne, Waldeyer, Izquierdo, and others, concerning the im-
* Dogiel. A. S. Pie Xerveii dor Coriu'a dt'.s Moiisclieii. Aiiiit. An/,,,
.ItMia. Hd. V (lyiM)). S. 48;}-4i»4,— Die Nervenendkorpefclu'n (Kndkolhen. W.
Krause) in der Cornea mid Conjiuietiva hnlbi dos Meiiselien. Arch. f. inikr.
Anat., Bdiui, Bd. xxxvii (If^Ol). «• «0','-(5iy.
GItOUPINO AND CHAINING T()(}KT!IKR OP NEURONKS. 4()1
nu'diato connoction botwec?! norvos and the protoplasm of the
connective-tissue cells of the cornea, may thus be explained.
iii^
Fi(!. !ili().— <i('nital lUTViM'orpiisclcsdf (lift'cront forms from flif limiiiin ulaiis penis.
(After A. S. Doniel. Areli. f. mikr. Aiiiit., Hoiiii, H<l. xli, !«!«, Tiif. xxxii,
Fi^'s. »i iind 7, uiul Taf xxxiii, Fig. 8.1 ti, mediillated nerve (ilires.
27
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15
Lit
402
THE NEIIVOUS SYSTEM.
I
.':t l< il'iii .;:
'iilisi
Tho cnornions number of nerve fibres which luive been de-
Bcribeil in the connective tissue of the mucous membrane of
the stomach and intestine by Krik
Miiller, Berkley, Ramon y Cajal, and
others, are thought by many to be
mainly motor for the innervation of
smootli muscle, and secretory for the
innervation of glands. There can
be but little doubt, however, that
among these are many fibres which
carry centripetal impulses. They
have been studied with the method
of (Jolgi, and also with the method
of Elirlich.
The nerve endings in the menin-
ges of the brain in animals have been
investigated recently by D'Abundo *
and Jacques,! who find that both
the spinal and cerebral dura mater
is rich in nerves, particularly in non-
meduUated fibres. With the methy-
lene-blue method free end-arboriza-
tions and pencil-like nerve endings
are to be made out inside the bun-
dles of connective tissue. Acquisto and Pusateri J have since
studied the endings in the human cerebral dura mater, and
describe and figure, in addition to vaso-motor filaments, endings
which are probably those of centripetally con 'ucting nerves.
They suggest the hypothesis that variations in the pressure of
the cerebrospinal fluid may by means of these lead to reflex
vaso-motor phenomena. If this idea be found later to corre-
spond with the facts, the nerve endings of the dura mater must
subserve physiological functions of no mean significance.
* D'Abniulo. La innervazione doUa dura madre cerohralc. Cominuni-
eazioiic fatta alia societa. Rifonna ined.. Anno x. Xo. 42 (1884).
f Jacques, I'. Note siir i'lnruTvation de ladure-inere nirebrospinalc chez
los matniiiifores. J. de I'anat. et pliysiol. [etc.], Par., t. xxxi (1895), pji.
59G-60!».
X Ae(iiiist<i, v., ed E. Pusateri. Sulle termiiiazioni nervose nella dura
madre cerebrale dell' unnio. Hiv. di patol. nerv., Firenze, vol. i (1896), pp.
267-270.
Fid. 201.— End Itull) from sliiiis
penis (if a white mouse. <(,
meduiiated nerve fibres, tlie
axiscylinders of wiiieli end in
a nerve sliein. From tlie skein
a fine nerve tihre can lie seen
ffoiuK out to end amonj; tiie
epitiieiiiil eells. i.Xfter \. S.
Dofiiel, .\reli. f. niilir. .Vnat.,
Honn. Hd. xli. 1S!»3, Taf
xxxiii. Fif;. IH. >
UKUUPING AND CHAINING TOGETIJEIi OF NEUIlUNES. 403
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TIIH NKitVOL'S SYSTEM.
1
(illOlTPING AND CIIAININC} TOCKTIIER OF NKriloNKS. 4o5
The sensory nerve endinj^s in tendons since they were de-
scribed by (iolgi* in 1HT8 have been the object of many
researches. Accord in}^ to (>ol}^i, tlicy form true terminal
|»Ia(iiics, from two to thirty of these phi(|ues makin<^ up a sinj^le
corpuscle (Fij^. v<i;5). Jle found them in voluntary muscles
located at the junction of the muscle fibres with the tendon.
The whole corpuscle, us described by (Jolf^i, is fusiform, and is
situated on the surface of the ten ' n, beinj,' formed of {granular
substance, and possessing an envelope of several hyaline con-
centric layers, in which are imbedded a certain number of
nuclei. The nerve fibres on entering the corpuscle lose their
neurilemma, but at first retain their myelin sheaths, dividing
into two or three mcdullated fibres, each of which then gives
rise to a true end-arborization of naked nerve fibrils. Each
(U)rpuscle receives at least one nerve fibre, though usually at
least four or five pass to it.
Very extensive studies of the endings of nerves in tendons
have been nuide since by Ciaccio.f He has examined the ten-
dons in several classes of vertebrates as well as in human beings,
and finds similar relations in all (Figs. )H')i-4i\'7). Thi! nerves
entering the tendons divide, according to Ciaccio, into several
branches, the individual fibres running in between the ten-
don bundles. On their way they lose their myelin sheaths,
and the coimeetive-tissue sheaths fuse with the connective tis-
sue of the tendon bundles. As the fibres pass on, they divide
repeatedly, and finally end free with small varicose bulgings,
surrounding the tendon bundles, in the form of spirals or rings.
The structures describctl by nuinv as nuclei in these endings,
Ciaccio feels sure, are nothing more than peculiar nodosities of
* fiulf^i, ('. Ueber die Ncrven der Sehnen des Menscheii utid anderer
Wirbcltiere imd uoher ein ihmios iicrvoses imisculo-tendiiiiisi's Eiuliirgun.
Uiitt'lsiK'liungtMl iii'luT (leii foinoren Huii des centnileii uiid [icripherischcn
Nerveiisystems. I'oheis. v. H. Teiischor.. Jena (1894). S. 2(W-21(J.
f (Mat'ek). (J. V. Iiitoriio allc ])iastre iiervosc fiiiali iif'teiuliiii de'Vcrte-
liniti; iiuovt' iiivcstigazioni riiicrosoop. Mem. Accad. d. sc. d. 1st. di h.)-
logiia. 1889. 4 s., vol. x (1H90), j)|). 301-;{24. — Sur les plaques iierveuses finales
dans les tendons des vertehres. Xou velles ivcherehes niicroscopifiues [Transl.].
J. de niicrog., I'ar., t. xiv (1890), 172: 201: 2:54. — Nuove invest iga/iuni tni-
croscopiclie intorno alio piastre nervose finale siii tcndini delle 5 classi di
vertel)rati. Rendio. Aeead. d. sc. d. 1st. di Bologna (189()-"91), pp. 19-20.—
Sur les |)hi((ues tu'rveuses finales dans les tendons des vertebres. Arcli. ital
do biol., Turin, t. xiv (1890). pp. ;il-.")7.
ji
■
V
4u(i
THE NEllVOUS SVSTKJr.
i
filJorPINT. ANP CIIAINIXf} TOfiKTflKFl OK MU'RONES. 4()i>
the ihtvc flhri's. He dciiu's dctiiiito ('iicaprtiiliition with cou-
noctive tiHsuc, such us (lolgi descrihod, and furtlicr hiys strcsH on
tho rc'liitioii of tlie fudinj^s to tlie tendons projuT, iiKU'ju'ndont
Fkj. 2ti7. — Tciidinotis expansion of on(> of the motor luiisclcs of the eye of an ox.
(After (i. V. Ciaccio, Aicli. ital. dc l.iol.. t. xiv, IHitl. pi. iv. Fin. 27. i Two
musciilo-tciKliiioiis organs of (iol^'i miiti'd with one aimtlicr ami (•oiiii)rcss('il
toward tlic lower cxtrt'iiiify liy a l)and of coiniective ti.-isue. Eaeli coriiiLselc
of (iolf{i lias its own ultimate nerve phKiue. These two i)la(iUes show lioth
the hushlike anil rinjjlike endings.
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TIIK NERVors SYSTKM.
of till' muscles,;! vifw aufiiiu in coutriKlictioti to tliat of (iol«,M.
The endings iilwiiys lie inside tlie tendons, a})piirently never on
Fui. ^(is. - A, sciisiny nerve ending iVom exiicMnliuiii of upper IimII' nf lel'i alriiiin
of I lie lieiirt dI' tlie Kray rat. U ami (', sensory lu'rve eii(liiij;s IVoiii the eiido-
eanliiiiii ol' tlie ilo^'. (After A. Siiiiriiow, Aiiat. An/,., Jena, Hd. x, l.S<)r), S.
Tir), Fi^'s. ;!. 4. r>. )
their sheaths, Ciiiccio calls them plaqto's trxdinnisrs arrr Irr-
wiitaimn hnissonnensr t/rs tirrfs a s/iinr/s on u (iiiiirdn.r. As
Jlliil!
!>'*•'{
JV
m
(JUOUPIXG AND CUAINING TOCJIOTIIER OF NEUUOXHS. 411
wo liiive siiid, these ondiiif^s of (iolf^i, riaccio, and Mazzoiii aro
probably closely allied to raciiiian corpuscles.
As to the eiidiuf^s of nerves inside the interstitial connective
tissue of organs we have data concerning the heart, lungs, and
certain ])arts of the eye. The sensory nerve endings in the
endocardium of the auricles and ventricles, as well as the
auriculo-ventricular valves and the chorda' tejidinea' of ani])hib-
ians and mannnals, have l)een studied by Sniirnow,* who has
also attempted to nnvke out the alterations in the endings after
seetioji of the nerves to which they correspond (Fig. v<>S). The
nerve endings in the lung have been exannned by Herkley,
Fl(i. 2()!). — Nerve emliutts in tlie liiUK of the IVoi,' ; liir^'e skein with iiiteiiuK
niednlliited nerve lihre (// 1 and t\vi( tli reads havilij; the skein n. (After. \.
Sniirnciw, Anal. An/., .lena. ltd. iii. l.sss, S. :i,-.it, Imk- ~. )
("nccati,+ and Smirnow J (Kig. •W.)). The endings here in the
connective tissue are not unlike those found in that of the
heiirt.
Melkich* has studied the free endings of sensory nerves
in the connet^tive tissue in the iris of birds by KhrliclTs method
and tlnds two viirieties of nerve endings in this region : On the
posterior surface of the iris a ple.xus of very tine nerve fibres
which, iifter manifold division and interlacing, end free, never
forming atiastomoses. The other variety, situated near the
* Smirnow, A. Uebpr die sensiblon Nerveni'iuliKun^t'n iin Ilcrzcn boi
Aniphibipii mid Siinj,'i>tii'rcn. Anal. Anz.. Jona. Kd. x (IHflr)). S. 7:«-740.
f ('ii('('ali,(r. Ihtonio al inodo onde i nervi si distrilmiscono etprniinani>
ni'i |)ohn(iMi e iiei iiuiseoli addoininaii liei Triton (.'vistatus. bilcrnat. Mo-
iialsclir. f. Anat. ti. I'liy.siol., Leipz.. Hd. vi (1889). S. 2:57-24!). Al^io IJuU.
<1. sc. ined. di |{oloe:iia. fl. s., vol. xxiii (ISHO). \>p. :iO-l-:i(t7.
\ .Smirnow, \. Vohw Nervenendkniiiiel in der Frosehliin^^c. Anat. Anz.,
Jena, Bd. iii (188H). S. 2rj8-201.
* Afelkich. r Keiintniss des Ciliarkrirpers nixl dnr Iris bei Vogeln,
initgelheilt von Prof. Arnstein. Anat. Anz., .lona, 15d. x (18'jr)), S 28-!i5.
K'
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TIIK NKRVOUS SYSTEM.
muscle fibres of the iris, arises from the division of modullated
nerve fibres which form free nerve endings after repeated den-
dritic subdivisions (Fig. 270). He does not think that thev
are motor fibres, but believes that they represent the sensory
element in accommodation, the first variety, according to his
B
FUi. 270. Sensory nerve IfndiiiKS in tlic eiliiiry Imdy (if liirds. (Al'ter Melkieli,
Anat. An/,., .lena. Hd. x. IS!),"), S. :{(», Ki<;s. U and :i. > A. sensory end arl)(iri/.a-
tion I'roni tlie ciliary liody near the elastic riiiK; a, niedullate<l nerve lilire ;
H, tendril-litce nerve endinfjs in connection wilii the niedulhited nerve liln-e
wiiich ari.ses directly from a nerve trnnk. At <i are seen some fjranular
plates.
idea, carrying impulses concerned in pain sensations. Very
similar nerve endings have been described in the connective
tissue of the ciliary body in the eye of the cat and of man by
Agababow* (Fig. 271).
Turning now to the sensory nerve endings in voluntary,
Ciirdiac, and involuntary muscles, the former nuiy first be de-
scribed. In achlition to Paciniiin corpuscles and end bulbs,
not unlike those described by ?r'*:i,u8e in tlie conjunctiva, which
occur in considenilde numbers in the muscles (Kerscbncr) and
the orfffnii iinisnili-fcudiiifi of Ciolgi, above referred to, the
principtd ending believed to be sensory in voluntary muscle is
the so-called muscle spindle (Kiihne, Forster) f or neuro-mus-
* .Akh'imIiow. .\. Die Innervation des Ciliarkorper.s. Anat. Am,, Jena,
Mil. viii (isi}2-'o;{). s. nnri-.^fii.
f Forster. riMuni. Zur Keiiiitniss der ^fnskplspindeln. Arch. f. path.
Anat., etc. Hcrl.. IJd. cxxxvii (1M!)4), S. 121-1'J4.
1 1
(illOUPIXG AND CHAINING TOOETIIER OF NEURONKS, 4\-]
(ulur bundle (Rotli). These organs were first seen in the frog in
18(51 by WeissniiUin, who thought tliem to be definite organs
inside the muscle. They have since becii studied and described
by a whole series of observers in many dilfercnt animals as well
as in luunan beings. Kiihne, who introduced the term " muscle
spindle," described a special form of the structure in reptiles.
Many authorities, among wliom may be mentioned Eiseidohr,
Babinski, and Fraenkel, have studied them in diseased muscle
and thought them to be pathological phenomena. In 1878
Ranvier expressed the view that they represented an especial
physiological mechanism standing in a definite relation to
the nervous system, a view which has been accepted l)y Roth,
Kerschner,* Christomanos and Strossner, Laura Forster, and
in fact by the nuijority of recent investigators.
Fl(i. )17\. — Nerve endings in eiliarv IhmIv (leiunnstiiited by tlie inetlind of (iol-ii.
(After A. AKiilialHiw, Aiiiit. An/,., .leiia, I5d. viii, ISlKi, S. TmS, !•'!>{.:>,) The
lifliire sliDWsa didicate nerve stem wliieli breaks up inln sinjile nerve til)res,
wliieli in turn run out to l'<irni end arUiiri/alions which lie at dili'erent depths
in tile tissue.
The muscle spindles consist of long, narrow, hollow struc-
tures, containing within them Siriijcd muscle fibres, l)lood ves-
sels, coimective tissue, and medidlated nerve fibres. The open-
ings iit the ends are partitilly closed by bundles of muscle fibres,
* Kcrschner. li. T'elior :NriiskcIsi)in(l('ln. Vorliandl. il. anal, (lesfllsoli.,
Jetia, Hd. vi (1S!)'J). S. Ho-S!!.— I?einiTi<iin<:eii uehor eiii Ih-soikIoits Miiskel-
•systi'in iin willkiirliclien Muskel. Anat. An/... .I.'iia. lid. ill (IHSH). S. !•>>»(-
1.12.— ncilrac ziir Keiinliiiss der seiisihlen Kndorirane. Anal. Anz.. .lena,
Hd. ill (ISSS). S. ',>SH-2n(i.— relief die Fdrtschritle in dor Krkenntiiiss der
Muskelsj iiideln. Anat. Anz.. .Tona. Bd. viii (lS!l-,>-ft:n. .S. 44it-4r)8.— Ikiner-
kniifjen zu llerni Dr. .\ii!iel(i Hnniiii's Anfsatz: CniisidtM-azioiii eriticlie stii
reottnti stndi ch'li' a|i|iMnit(> iiervdso iiei fiisi uui.sL-olari. .\iiiit. Aiiz., Jenu,
Bd. ix (18!)3-'n4), S. r)5;{-503.
P:
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414
TIIK NKUYOUS SYSTKM.
l>\
'tl^y
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S M ^'* '■!•>- ^^^^
MiPi;^^:
vessels, nerves, iiiid connective tissue. The whole mass of
structures iuclosed in a coinnion sheath is considerahly wide r
/, in the nii(klle than at tlie end.
Lymph intei'spaces exist throu<;h-
oiit the spindle, while through the
centre of it runs a lymj)!! space of
consideralde size. The slieath cor-
responds in character to the peri-
neurium of a peripheral nerve. At
the ends of the spindle it is thin,
but it increases in thickness to-
ward the w'dened parts, 'i'he num-
ber of striped muscle fibres present
in a single apindle varies in its dif-
ferent i)arts They are usually
fewer at the ends, where the fibres
are also finer, more numerous in
the middle of the spindle, where the
individual fibres arc also thicker.
The fibres are l)eautifully striated,
as one can easily make out in longi-
tu<linal sections. The nerve fibres,
like the muscle fibres, vary in num-
bers at different levels in the spin-
dle. Forster * found eleven mus-
cle fibres and six nerve fibres in a
cross section of one spindle, and in
that of another ten muscle fibres
and eight nerve fibres.
The nerves enter the spindle in
dilferent parts of its course, pene-
■ ^ /^ //yf-J-.-JJ.
Fio. 272.
Vui. 272. MuscuUir spiiiiUc iVoin iiiyoxus
iivrlluiiariiis. (Alter S. 'rriiiclit'Sf, Mcin.
Aiciul. (I. sc. (1. (st. (li ISoloKiiii, 4. s..
t, x, ISSit-'ilO, V'\n. 7.) <(, sliciitli (if till-
imix'lc spimllc ; (•.•.•, axis cyliiidiT ih'iic-
tratiiiK tlir iiitcniui'li'ar pnitdiilasiii ; ex',
aimllicr axis cyliiidfr cult riii;; tiii' iiitcr-
iiiiclcar iir(p|cii)lasiii ; I'c. iat'K"' axis tyliii-
(Iit; (•(/. rf. axis cyiiiKlcr pciictratiiiK tlit'
intfi'iiticlcar protiiiilasni : c/i, axiscylindiT
ill various depths of llic iiiterniiclear prii-
tiiidasiii ; /, nuclei (il'tlie iiniscics.
Op. cit.
(ilJ()riMX(5 AND CIlAINIXa TOGKTIIER OF XKUUONES. 41.-,
ating the sheath after running a short distance in it. They
are often accompanied by blood vessels, which are present not
only in the capsule, but also inside the neuro-uiuscular ])un-
dle. The muscle and nerve fibres inside are separated from
one another by strands of white fibrous connective tissue. He-
tween the sheath and its contents is situated a peripheral lymph
space through which a few single libres run.
The num])er of spindles in a single muscle is very large; as
many as thirteen have been counted in one cross section through
the genioglossus muscle. They may be situated in the various
parts of the mnscle itself, in the external perimysium, partly in
tiie tendon and partly in the muscle, or they may be wholly sur-
rounded by tendon. 'I'he bodies arc especially easy to demon-
strate in cases of muscular atrophy in human beings, and they
have already been studied and described in a large nund)er of
such cases.* Spillerf has recently reviewed the bibliography of
the subject, and his paper is accompanied by an excellent illus-
tration. As to the sensory nature of the sjiindles there can be
no longer much doubt, for when the motor nerve fibres supply-
ing the voluntary muscles have undergone almost complete
degeneration as a result of disease of the lower motor neurones,
the majority of the nerves in these structures may remain nor-
mal. Sherrington J proved by physiological experiment that
the spindles are connected with the sensory roots of the nerves.
\\'hile it is true that motor nerve terminals have been occa-
sionally found ill the muscle fibres inside these bodies,** the
majority of nerve endings which have been thus far demonstrated
are of the sensory type. In 1H8U Trinchese || gave a good illus-
* Ilorsley, V. SIkuI Xotc on Sense Ori^tans in Muscle and mi tlio Pres-
ervation of Muscle Spindles in Coiiditions of Hxlrenie Muscular Atrophy,
following Section of the .Motor Nerve. ISrain. iiOiid., vol. xx (1H!»7). p. J??").
•f Spiller, W. G. The Xeuro-^ruscular IJundles (Miiskcl-Knospen, Mus-
kelsiiindeln, faisccaux neuro-tnuseidaires). .1. Xerv. and ^Ment. Dis., X. V.,
vol. xxiv (lyitT), pp. (»','6-(i;5(».
I Sherrington, C. S. On the Anatomical Constitution of Xerves of
Skeletal Muscles; with Remarks on Recurrent Fibres in tlie Ventral Spinal
Nerve- Root. ,1. Physiol.. Camijridge, vol. xvii (1H!)4). pi>. 211-258.
* Kerschiier, L. Op. rif.. Anat. Anz.. .Tcna. 188S. S. 2!lo.
!| Trinchese, S. ("ontriliuzione alia conoscenza dei fusi muscolari. Mem.
r. Acca.l. (1. sc, d. 1st. di Bologna, 4. s., vol. x. 188!l [18!l()]. pp. 715-725.
Also Transl. : ("ontril)iition a la connaissance des fuseaux niusculaires.
Arch. ilal. de iii.il.. Turin (18i)()-'))l), t. xiv, i)p. 221-230.
i\
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THK NKHVOUS SYSTP]M.
tration of tlioso structtircs (Fi<r. '^7'2). Kxcollcnt (lemnnstni-
tions liave hct'ii ^ivcn l)y Hulliiii.* lie finds clahoratc soiisory
t'lidiiif^s resulting,' from the maiiifohl .subdivision of the axis
cylinders of the nerve fibres inside the si)intlk\s. lie distin-
guislies three varieties of these endings: teniiiutiiiiotis a an-
'nf(ti(j\\\\\vn' the nerves surround tlie muscle fibres in rings;
tmiiindixons i) spindt'.s, where tiiey go around them in a spiral
fasliion ; and terminaisoHx i) Jiriirx, where they end upon tliein
with complicated dendritic branchings (Figs. :i7;3 and :i74r).
A
A
Fk;. 273. — Mi(l<lk' tliird of a tcMiiiiinl iiliuiiic in tlic niusclc spiiidlt' of an adiill
cat. (.\ftcr A. Kiitlini. Arcli. ital. (If liiol., Tmin, t. xviii. ISSKJ. \>. \m. Fi^.
1.) .Sspinils; .1, riiifis ; /•', (Icudritic liiaiichiiiss. (Iiloridi'-ol-gold prt'para-
tioii.
ITnber, of Ann Arbor, has recently studied these structures
with the methylcne-l)lne method, and has succeeded in obtain-
ing exquisite jiictures of the nerve endings even to their ulti-
* Rndini, A. Sulla tfriuiiia/.iono iicrvdsa iici fusi nuiseolari e siil loro
sij;iiificato fisi(il(if,Mc(i. Xota pivvciiliva. Atti d. r. Accad. d. Liiicci. ("I.
di sc. fis., mat. c iiat.. Hoiiia. ~. s., vul. i, 1892. — Siir la teriiiiiiutiori iktvimix
dans Ips faisceaiix imiseulairesot siir Iciir sijjiiification physiolosiqiio. Aivli.
ital. do liiiil,. Turin, t. xviii (1S!)2). pp. 1()(J-114. — ('(insidi'i'azioni critidio ."^ui
receiUi stiidi deU' apparato ncrvciso iici fusi nuiseolari. Aiiat. An/., .loiia,
Bd, ix (lH!W-'!>4). .S. H0-H8. — Sulla fina anatomia dei fusi neuro-museolari
del tratto (' sul loro sigiiirK'ttto fisiologieo. Monitore zool. ital., Fircnze, vol.
vii (18%), pp. 49-53.
(HioriMXli AND (ilAIN'IN'd T()(JETIIKH OF NKrUOXES. 417
mate tcrTiiiiiatiiiii (Fi;:. '.'i.")). 'riiaiiks to liis cdurlt'sv, 1 liuve
had tlu' opportunity of I'xaniiiiini: liis spt'i-iiiu'iis, and have
-Tt^
I'lii. ;.'7l. — A stripril iim^clc liln'c in ;i Iiiiiiimii iiiiim Ic spiiiillf willi lirniiinii-iiiiis 'i
llriirx. (Al'iii- A. IJiilliiii. Aicli. itiii. i\i- liinl.. 'riirin. i. wiii. l^lKi. p. Ill,
V\ii. ,'.1 /.', Iiriiiiiiiil ciiiiirgciiuiits nl' the axis cyiiiMUr. ( lil(iri(l(-cit-<;iil(l
pn iKiraliiiii.
hecii iiiiicli siirj)ris('(l at the coiiiplcxity of the oiuliii'i'.s. His
rt'siilts, to<,n'tlu'r witli i)lati's and a vt-rv coniplete bihlioirrapliy,
have l)ecn enihodiod in a n-ct'iit pajxT hy himself and Mrs. Dc
Witt.* Till" method of Silder t is also of great service in deiii-
onstratiiiiT the niUfiele spindles. To .succeed with the method
some care has to be taken in teasiiiir out the preparation. 1
have had the i^ood fortune to see soiiu' of Sihler's preparations,
ami can speak in hiiih terms of his method. The contrast 1)e-
tween the larijfe calihre of the seiisorv tiltres uoinir to tliese struc-
■ '" n
',;
t-.:
»'i
ii!
\
* Iluljor. G. ('.. and Lydm M. A. De Witt. A Contribution on tlic Motor
Ni'i'vo FiiidinfTsand on tlu' Nerve Hndings in the Muscle S|iindk'.s. .1. Coniip.
Neurol., (iranville, vol. vii (ISIIS), |i|,. lOW-',':!!).
f Silder. ('. Ueber eine li'iciiteund siidiere Metliodedii' Nervenenditrunj;
an MuskeU'aseMi und (ietassen naeli/uweisen. Areli. t. Aniit. u. I'liysioL.
i'hvsiol. Alitii.. Lei|iz. (IS!).')). S. 20'2. — I'l'ber Muskel.-pimlein und intra-
niuskuliii'e Nervenendis;nni::en bei Seldansjen und Fniselien. .Areli. f. niikr.
Ainit.. Bonn. Md. xlvi (ISfl.j). S. 70!)-T'i:!. — .\ description of a simple and re-
liable nietlu.d to trace the nerves in the muscle. Clevclaml M. Gaz., vol. x
(b'^m-!).-)). pp. 'rM--2f.4. Also. Am. Month. Micr. .1.. Wash., vol. xvi (1S!I.-,).
Pl>. IT'2-IS'^.— The sensory end-orjrans of voluntary nuiscle. Cleveland M.
(biz., vol. \i (bS!».-,--ii(i). pp. oO.VOOO.
28
n
il
III >i
iiii
'I
ti
■ns
THE NERVOUS SYSTEM.
tiii'cs and tlio imu'li sniiillor ciilihiv <»f tlii' ordiiuvry motor nerve
tihri's of iiuisclo was vury .strikiii<;.
F'Ki. »75. — ^tiisclt' s|iiii(ll(' friiiii intrinsic pliintar niiisrics nf a do^. (After (i. ('.
Ilnlicr and Lydia !)<• Witt, .1. ( '.mip. Ni iircil., (ininvillc, vol. vii, 1W»S, pi. .\\ ii,
I'itl. IW. I Sy. II., syiniiallutic vasipniotor li)prc.
The wliole inake-up of tlic inusi'le s])iii(llo or ncuro-innsciilar
biiiHlU' imprt'ssi'S one as a structure esjjecitilly adapted its a sense
organ to give information coneerning vtirious states of tension
in the muscle. Contraction of the muscles in which they are
situated must necessarily lead to alterations in the pressure of
the lymph inside them, and I am inclined to tigree with those
observers who assign to tliem tin important function in con-
nection with muscular sense. The subject is, hoAvever, still
obscure, and the last word concerning them has by no means
yet been said. Renewed attention is being jKiid to them just
now by the neuro-pathologists. I need only refer to the care-
ful studies of liatten * iind (Iri'inbaum.t
The nerve endings in the heart muscle have been studied
by Herkley, J Dogiel and Tumarzew,* lleymans and I)emoor,||
* Button. F. E. Tlie Muscle Spindle nnder PatliDlogical Conditions.
ISiaiii, Lend., vol. xx (IHiC), i)]). 1^8-17!).
f (iriinbuiiin, .V. S. Note on Muscle Spindles in Pseii(lu-IIypertroi)hie
I'aialysis. Bi-aiii, Loiid., vol. xx (1S!)T). pp. ;!(;r)-;j67.
I Berkley, H. .1. On Complex Nerve Terminations and Ganglion Cells in
the Mnsenlar Tissue of the Heart Ventricle. Aiiat. Aiiz.. Jena. Bd. ix
(18!t;5-"!»-l), S. 33-42.
'* Dogiel, J., u. Tnmarzew. Contribution to the Comparative Anatomy and
Physiology of the Heart. (Russian) Medyeyna, Kasan (1893). Nos. 4(! and
47. Abstract in Merkel-Bonnefs Ergebnisse der Anat.. Bd. iv (18!)4). S. 2!t!);
also Dogiel. A. S. Die sensiblen Nerveneiidigiingeti im llerzen utid in den
Blutgefiissen der Saiigethiere. Arch. f. inikr. Anat., Bonn. Bd. lii (1898),
S. 44-70.
II Heymans, J. P., et L. Demoor. Etude de I'innervation dn ca-ur des
0ItOUI'IX(} AND CIIAINlNd TOliKTIIER OF XEUllOXKS. 41()
Jac(|Uos,* and Iliilicr and Dc \\\U. Wlu'tlicr or not the com-
1)U'X felt work (tf til)ri'S whifh tlu'si' invi'.sti<,'ators find tlirouf^li-
out the ori,'iiii have to do witli the mediation of centripetal im-
I)ul8e8 or whether they are concerned wholly with the currying
of motor impulses to the heart nuiscle fibres has not yet been
determined. The fil)res in Fi<r. "-.'Tfi are believed by Huber and
I)e Witt to be niotor.f Similar doubt exists eoneerninij the na-
ture of nerve endings in smooth nuisele ; enormous numbers of
fine fibrils have been found in smooth muscle membranes, and
their exact relation to the fibres has in some cases l)een care-
fully studied ; l)ut how many of these are motor and how many
of them are sensory, remains for further investigation to deter-
mine. Certain it is that the walls of tubes which have smooth
muscle coats are well sui)plie(l with sensory nerves. To make
I'"l(i. ~'7t). — Surface view of canliiu' iiiiisrlc cells with nerve endiiifrs. ' After G. ('.
llulier and Lydia I)e Witt, J. t uuiii. N enrol., (iranville, vol. vii, ISits. pi, .\iv. )
this clear I have only to mention th.e intestine, tlie bile duct,
the ureter, the bladder, the uterus, and the blood-vessels. In-
testinal colic, biliary and renal colic, are accompanied by a vari-
vertei)res a raitlo do la inetluxle ile Golgi. Mem. cotiroii. Acad. roy. de med.
de Belg., Hnix.. t. xiii (18!»4).
* JacMjues, I'. Rceherchos siir les iierfs dii c(eur eliez la greuouille et les
niamniiferes. J. de runat. ot pin>i<il., etc.. Par,, t, xxx ()8!(4), jip. 62'2-(54s,
f The sensory nerve endings in the lieart described by Smirnow are situ-
ated in the connective ti.ssiie, not in tlie niuscle.
1
1 ^
Uf
iil
'liiili
III!
(■
('
mm
420
Till-; NKUVOLS SYSTEM.
cty of ])iiiii, clwinictcristic ciioiiLrli to lie (U'sifriiiitod jis " stnootli
imisclc pain." 'riic lalior pains coiiiirctcd with coiitractioiis of
tlu- utuniti an- of a similar iiaturf ; tin- .si-veri- pain bi-iicvcil li)
Fl<;. ^'77. — liitrriiiiiM-iiliir' cuil iirlMifi/Mlimi I'nnii tlic lil'l wiill of tin; IiikIicm (if
the <l(i,i,'. Tin' liniiiil iiiciIiiIImIiiI ihtvi' (ilu'c liclcumjiy to i; i> visihlc fur
MiiiH' ciistinicc. Mi'tliyiiiu -liliif iirciianilinii. Aflir A. Ai'iikIi in. frciiii
lltiillirr's trxl-lMHik. I
iiiaiiv to !)(' associated with spasino<lic coiitrait ioii of the l)i(ioil-
vessels (an<rina. iniiiTaiiic) may also bf thouuht of here. l>ut
whotluM- the pain in tlu'sc cases is tiic ivsnlt of stimnlation of
Fiii •J7t-i — [,nn^;iniiliii il x'ctioii uf iiivulinitiiiy iiuiscic slidwinj; iicrvc I'lidiiiiis
I AHiiMi. <" lliilii TMiiil l.yiliii Dr Wilt. .1. (nu\\>. Nciiml.. ( ininvill.'. vnl. vii,
ISits, pi. xiv. I'ijis. ;.".' :iii(l ~':i. ) K.iixis < ylimlir t(iii\iii;iliiit; : /). tin- Icniiina-
tiiiii itx'lf; II. imcltus 111' till' siniiotli miisi-lc ci'll.
si'iisory niTvo iilu't's l)c',i:-innini>- in tiu* mnsclr itself or in the con-
ut'ctivo-t issue structuros is not known. In the trachea intcr-
•"■ L-
fM{OUIMX(} ANT) CirAIMNfi 'nuJiyniKK OF NKFRONKS. 4.JI
muscular nci'vc-ciidin^rs have Itt'cii (lenioustratcil hy Arnstcin
(Fig. 5^77). 'I'lic iii'i'Vf ('ii(lings(k'scril)t'(l in connection witli the
smooth musch' of tlic iris and ciliary __
holly ari' (louhtlcss concerned in the
meciianism of pupiUary contraction and
of accommodation reaction. In Fi^^.
'ijS the motor cndinjjs on the smooth
muscle-cells of the intestine are illus-
trated. Tlie iliulings of Hetzius on tlie
vasa afferentia in the glomeruli of the
kidney are shown in Fig. 27^. The
nerve endings on the lymph vessels
have recently hceii descrihed hy Dugiel.*
Recently nerve endings have heen
found ill certain pathological new
growths. Thus Reisner f has found
nerves in condylomata, and \'ollmerJ
has also studied nerve eii lings in these
growths. Young,** in his study of nerves
in tumors,has successfully demonstrated
nerve fibres, both medullated and iion-
medullated, in a considerable number of
these growths. He concludes that, in
sarcomata at least, nerves are just as much an integral part of
the tumor as are the sarcomatous blood-vessels. The nerves
were not followed, however, to their ultimate terminations, and
it must for tlu' j)rcsciit remain (loul)tful whether they represent
purely vaso-motor tilameiits or whether among them dctinite
sensory fibres also exist.
Fid. -'"(•. — Nerve ending nii
the Viis itll'ereiis in the cin-
tex iif the kidney. ( After
(i. Ketzins, Mini. I'nter-
such.. Sinckhcplni. I in, ecir-
pnsenhi icnis ( MulpiKlii) ;
Id, vii.s iiU'erens ; 11, nerve.
V !
* Ddu'iel. A. S. Die Xerveii ilei' Lyniphgufiisse. Arch. f. iiiikr. .\ii!it.,
IJciiii. I'.d. xlix (mil). S. Titl-Titr.
+ IieisiuT. A. Uebcr das Vorkoiniiieii vdn Nerveii in spitzcn Cciidyluineii.
Arch. f. DeriiKit. ti. Syidi.. Wieii 11. Leipz.. lid. xxvii (1SI14). S. 3Sr)-:!!»(i.
I X'ollini't', K. Nerveii uiid Nerveiieiidi;;iiii,i;en in spitzeii Condyloinen.
.\r( h. f. Deiii'iit. 11. .Syph.. Wieii u. beipz., Bd. xxx (1895), .S. 3G3-;JH(».
» Op. fit. Cf. Ciiiip. IV, p. :ST.
I'
mm
k
J.
CIIAPTKn XXXII.
CKN'TUAI. AXOXKS Ol' I'KIU I'll KKAL CKNTHIPKTAL VIU'ROVKS.
l''il)rp.s of (lorsiil rcinls — Origin, (•oursc, hraiicliiiij,'. ami li'i'miiiatidii — liUtcral
ami iiit'dial l)iiii(liL' of (|i>r>>al root — Kiitry zoiit' — Methods of stmlyiiij;
inlraiiit'diillarv fdiitiiuialioiis of dorsal root llbrcs — Myfliiiizatiiui of
lil)ri's — Stiidit!!! of Flcclisig, von Brclilerew, Kiirn.siii, and Trcpinsixi —
Vt-ntral, middle, and dorsal root zones — Fleelisijj's oval centn — Heia-
tioiisof inyclinizatioii snli-systenis to function — 'rrpi>inski"s four ftrtal
snl)-sy.steins — Stuilies of tabes.
CcufrfiJ A.rnui's of Pcn'/ifirrirl ('rutrijK'ftil Xcuronrx. — TTavin?
considered tlie inedullated ])eriplieriil sensory nerve fil)res (distnl
l)roeesses of the s|)inid »fan;,dioni(' cells) it is next in order to
consider the proximal processes of those cells, those which enter
the central nervous system. The central prolon<,'ations of the
spinal gan.ulion cells (which tojrether make uj) in mammals
almost the entire mass of flhres in the dorsal roots of tiie sjjinal
nerves) apjjroach the s])inal cord and plunge int(» it ut the dor-
sal lateral sulcus where the neurilemma of the individual fibres
is lost. The fibres on entering the cord divide by Y-shaped
divisioTi into an ascending and descending branch. Of these
tlie fornu'r runs a shorter or longer distance before terminating
in the gray matter of the cord or in the case of some fibres in
the medulla oblongata or cerebellum ; the descending limb ter-
minates in the gray nuitter of the cord after running downward
for a very short distance. On their way these axones before
and after division give off numerous collaterals which also run
into the gray matter to end free among the cells and dendrites
of cells situated there. In this way the mechanism is su])plied
])y means of which the impulses arriving by way of the periph-
eral sensory neuroiu'S can be transferred to motor lu'urones in
the cord or to centripetal neurones of a higher order which in
turn conduct impulses to higher regions of the nervous system.
The regions of termiiuition of the fibres are, it will be seen, of
422
<JItOlTI»IN(J AND niAININO TOGKTIIKU OK NKl'UONKS. 4-J3
very considerable extent, iind inelude not (tnly those of the ter-
iiiiuationrt of the main lihrcs* hut also those of tlie teiMnina-
tioiis of tlie coHaterals. Altliou;;h an eiiorinons amount of work
lias been (h)ne eoneerninj; the more t'xaet distribution of the
(htrsal root fibres on tiu'ir entrance into the cord and the course
foUowed l)y tiieir iiitraiuedullary i»rolon^'ations, we are even now
in tile dari\ concerninjf many |toints. 'I'iiis faet will lu' cvidciit
from the followinj,' summary review of some of tiie principal
contril)Utions in tliis field.
It was early observed that each dorsal root of a spinal nerve
on enterinfX the cord consists of two more or less dilt'erejitiate(l
bundles, a lateral bundle consistin<f in the main of fine fil)rcs,
and a medial, much lar<;er bumlle, consisting of coarser fibres.
Lissauer t showed that the tine root fibres become separated
almost immediately after entrance into the cord from the coarser
fil)resand passover dire( tly into thi' ]H'rpendicular column wiiich
he te'"med the " marginal zone " {Ikinu/zdiir), liow usually spoken
of as Lissauer's fasciculus. The fli)res of this fasciculus are easily
recognizai)le by their small size. The rest of the fil)res pass me-
dialward, a large nund)er of them running in for a longdistance
close to tiie dorso-medial surface of the dorsal iiorn tif the gray
matter. This zone is easily recognizable in well-stained Weigert
preparations of the adult cord cut at suitable levels, and has
been called by Stri'impcU and Westphal the " root zone " or " root
entrance zone." It will l)e spoken of here simply as the itifri/
ziinc of the dorsal roots. The further course of the til)res was
for a long time disputed. Before the period of the newer inves-
tigations many authorities believed that the dorsal root fibres
turned directly into the gray matter of the cord and were direct-
ly continuous either with cells there or with a network or felt-
work. It is now known that relatively few dorsal root fibres
enter the gray matter to terminate exactly at the level of their
entrance. On the contrary, the majority of them run up and
down in the white matter after bifurcation for some distance
before entering the gray substance. When they do enter the
gray matter they are not found to be the processes of cells situ-
ated there, but end by exhausting themselves by multiple sub-
* Sfiimmt'ttni'ni of the (iLTmaiis.
\ liissauer, II. Boitrnjjzuiu Fasorverlaufim Ilintorhorndosineiisclilirlii'n
Iiiifkeiiinarks uiitl zuni Vcrlialti'ii (losscllx'ii l)ci Tali(>s dorsalis. Arch. f.
Psvc'hial. \i. XiTveiikr.. IUtI.. liil. xvii (1S8U), S. 377-4:38.
V
: f!
m
¥
TV,
I
f']i
424
THE NERVOUS SYSTEM.
division, coming into ivlation with other neurones only by con-
tact or concrescence.
A knowledge of the intramedullary course of these medul-
lated axonesof the dorsal root fibres has been gained, aside from
the simple topographical studies of serial sections, in the main
through (1) the application of enibryological methods; {'-i) the
study of secondary degenerations, {a) experimentally produced,
antl (b) the result of disease in human beings ; and (3) the
chrome-silver method of (iolgi.
His's researches showed that the dorsal fasciculi of the
spinal cord are embryologically the result of ingrowth of the
central processes of spinal ganglion cells. A comparison of
the number of fibres in the dorsal fasciculi with the total
number of those of the dorsal roots prevented many from
believing, however, that the dorsal fasciculi were made up in
the main of dorsal root fibres. At this time the Y-sha])ed
divisio!! of the dorsal root fibres inside the spinal cord had not
been discovered.
The myelinization of the various ]iortions of the dorsal fas-
ciculi has been carefully studied by Flechsig,* von Hechterew,f
and Karusin.J
Flechsig's studies early convinced him that the fibres of the
dorsal roots and of the dorsal funiculi do not become nu'dul-
lated all at oiux\ On the contrary, definite groups ri'ccive
their myelin at very ditferent periods. A study of human
fcetuses at different periods of development has established the
sequence of medullation in the dilTereiit l)Miulles, and Flechsig's
description of the dorsal funiculi is based u])on the results of
this developmental analysis, and largely upon jjri'parations
made by Trt'ijinski in his laboratory. Each dorsal funiculus,
exclusive of (JoU's bundle (fasciculus gracilis), can, according
to Flechsig, be divided into the following areas :
(1) The ventral root zone {rorilrrr \\'iir:c/:iiHr).
* Flt'clisijr. P. Die Lpituiiffsbnhnen iin Gcliirn und RUekoninark. I^i'lpzij:
(ISTfi). and especially in his article 1st die Tabes dorsalis eino " Systein-
Krkraiikmii,'." NVirnl. (VnlniHil.. Leipz., IVl. ix (ISilO), S. :!:!: 7-2.
t Vi.ri I5r !litere\v. W. Die I,i'itiiiii,'sl)MliiieM iiii (ieliirii und Iviiekenniark.
I.eip7.iff(lH!t4).
t Kanisin, P. Das Fasepsystem des Kiiekeiimarks. enlwickidiiiiirs'je-
seliiclitlieh untersiielit. Moskau (1S94). Abstract l>y Stieda in Merkel-
lioiiuet's Kri^eliiiisse der Anatoiiiie u. Entwiek., Hd. v (IHSi.")). S. ft.").
OKUUI'LVJ AND ('1IAIXIX(J TOGETIIHll OF NKUUONKS. 405
--, ijpy ;
ill
h 1
f '
if 1
• :
li
i
{'I) The inifldk' root zono (i/iiftlrre Wurwhitiiu).
(0) Tlif (lort^iil root zonu {Itinlvrc WurzvIzuHf).
(4) The meditui zone {ineiUune Zone dcr Ifiiifi'rsfra>/f/r).
Tlie iiiediau zones of the two sides nmke u}) in the lum-
har region what is often spoken of as tlie oralrs < 'nit ruin of
Flechsig. The middle root zone develops in two parts (first
and second systems of the middle root zone), as does also the
dorsal root zone (medial and lateral portions of the dorsal root
zone). Tlie position of these various zones is clearly shown in
the accompanying diagrams (Fig. :2S()). The sequence of nicd-
ullation is as follows :
(1) The ventral root zone (Fig. 2S0, V.r.z.).
(•.>) The first system of the middle root zone {M.r.z.) and
the median zone.
(o) (iolFs fasciciili, second system of middle root zone aiid
the medial portion of the dorsal root zone {/Kr.z.).
(4) Lasi. of all toward the end of fo'tal life the lateral por-
tion of the dorsal root zone (Lissauer's marginal zone) (Fig.
:.'S(), /'.A.).
Of these the only bundle to increase steadily in cross section
as one passes up the cord is (ioll's fasciculus. All other regions
show in the thoracic cord, especially in its middle parts, a consid-
erahlv less area in ci'oss section than thev do in the enlargements.
As to the origin and termination of the nerve fibres con-
tained in the dilferent fu'tal zones, Flechsig, when he wrote in
IS'.iO, believed that the ventral root zone (V.r.z.) received very
many, probal)ly all, of its fibres direct from the dorsal roots of
the spinal nerves; they went, he thought, into the dorsal horn
after a longer or shorter course. In front of the dorsal horn
they vanished, although he could not make out their exact ter-
mination, lie felt sure that they have nothing to do with tiie
luu'leus dorsalis.
The iibres of the first system of the middle root zone he
ln'iicved come entirely from the dorsal roots and end after a
short course l)y turning into the nucleus dorsalis (Clark ii). As
to the origin and termination of the fibres in tlie median zone
he could make no statement. Coiu'crning the fibres of (iolFs
fasciculus, Fli'chsig could given irect proof from the study of
tlie fu'tus that they have their :i in the dorsal roots, lie
could first certainly demonstrate ihem as compact bundles of
fibres in the rcLrioii of tlii' tenth thoracic nerve. Further down
:& '•
4''^
ii.-;
'J
\!
t»
. inifi :
A
D.r.T
.. r9
(Am Fq. Rr.z.
Fes.l ,
F. CSV
Middle of iiitimip.sc('iitiu('crvi<'iilis : A. iiicnilicniiciit of ilnrsiil fimiciili iis rcvoalccl
by study of luyi'liniziitioii ; B, lesion in a case of incipient talies.
1 ^-7 Mr.z D.,,z.
D. ! r^ i 1]^.
Fes. I.
Fcs.l
'•Fes.l.
"Vr.i
E.
Pars tlioracalis : ('.section tliriiii};li niid-tlioracic refrion ilhistratinK inyelini/a
tion nienibernient ; I), section tlivoUKii iiiiiier thoracic region siiowiu^' lesion
in a case of incipient tahes.
D.r.z'.
FL..
Frs.L.-
FL.
f^')hM.n-t.
V— Urz
Intumesceiitia liimhalis; E, menilierment as revealed l)y study of inyelini/;ition ;
F. li'sion in a ease of incipient ta'ies.
Fl(i. ^»SO. — ri<;nres illustratin;; the dorsal fnnieuli in tlie cervical, thoracic, and
liiiidiar regions of the spinal cord. Those on the left side illnstrate the eni-
hryolo«ical nieiiilierineut, those i>n the rij;ht side the lesions iu cases of
incipient tahes. ( .U'ter P. Plechsii;, Nelirol. Centralhl., l.eip/.., ]{d. i.\, 1S!H(,
S. "J, Kifrs. 1. :,'. ;i. 4. 5. aii<l ti. i Letterini; ixplained ii text.
<iU0L'I'ING AND ClIAINIXC. T(KJI«:TIIEI{ oF NHruuXKy. 427
the fibres ai)peare(l to be distributed over tbc wliob- cross sec-
tion of the iiii(Ulle root zom-.*
The fibres of the medial portion of the dorsal ro(jt zone
(/>./•.;..) all come, according to Flechsig, from the dorsal roots.
They leave the dorsal funiculi by three paths : {<i) The fibres
most medially laid run in j^art in the raphe forward to the dorsal
commissure and then bend out toward the dorsal horn. These
fibres have nothing to do witli (foil's fasciculus. (Ij) The lat-
eral filjres leave the dorsal fasciculi from the side, crossing
the entering doi'sal roots at an acute angle, and arrive at the
dorsal horns, wheiu-e they run forward, (r) The main mass of
fibres runs through the middle root zone to enter the dorsal
horns midway between the dorsal commissure and the perijdiery
of the cord. These bundles run forward as far as the periphery
of the ventral horns, becoming lost between the fibres of the
ventral roots and the large ganglion cells of the ventral horns.
The fibres of the lateral portion of the dorsal root zone ( Lis-
sauer's marginal zone) run, just as Lissauer described them, to
the fine plexus of fibrils in front of the dorsal commissure and
to the lateral limiting layer of the gray substance. All fibres of
this zone, Flechsig believes, have their origin in the dorsal
roots, f
This memberment of the dorsal funiculi does not coi'respoiul
to that based upon secondary degeneration after lesion of
dorsal roots {ride iiifra)^ and apparently the former, unlike the
latter, docs not correspond to the ditt'erent length of the fibres.
It is Flechsig's oi)inion that his areas correspond to specific
sense (pialities (muscle-sense, sense of touch, of pain and the
like), the diiferent systems having different peripheral connec-
tions. While the areas outlined by degeneration secondary to
lesion of dorsal roots differ much from tliose which result from
* Kiiilicr, Fli'i'lisig liclicvcil that tlu> filn'fs of (idll's fascit'uliis have tlu'ir
orij,'iii alsi) in tlie dorsal /oiu'. and iicrhaps evoii more widely. They arc indif
numerous in tlie medial portion of the niiddlc root zone than in the laU ral
portion. Flechsijj helieves. however, that the fibres of (ioU's faseicnln-!
really represent intramedullary continuations of dorsal root filires, and urges
against von Rechterew's ol)jeetion that the dorsal roots are all luedullated
before GoH's fasciculus, that his own ohsei'vations sliow that when the filircs
of (ioli's fasciculus receive their myelin sheaths there are still uuiuy lilires
in the dorsal mots which are non-meduilated.
f It will l)e noticed that this description liehnigs to the period preceding
that ii' wiiicli collaterals were dislingui>hed from terminals.
n
it if %
% k
f
;i I
ii
in a
1 [
^
%
iji
il
lit
« ')
'If
fi
t.
4-2^
TIIH NERVOUS SYSTEM.
(•iiil)r\()l()<iiciil analysis, Fleclisig asserts that in locomotor
ataxia tiie lesions in the dorsal funiculi conform to the latter
>n H' S3
F'n;. 2sl.— I"|)])or half ol" Imiiliar I'lihirKciiicnt (if":i fn'tiis ;5.1 cm. Idiit; ; ciprri'spdiiil.-.
tn I'is;. '^so. K. /'.< liit( nil pyraniiilal trait : r, vciitial lonts iiicdullatiil ; h.
ildisil I'lMitsiiartly iiii'diilhittil : ill', vciitial rout zuiu' nt' ilinsil funiculi; n IV,
dcirsal rciot /uuc i lateral |i<prtiiin df ilursal funiculi ( Lissaucr's lasciiulus ;
/( ir, dorsal loot /one (medial jporlionl: >■••■. dorsal root zone 'most median
|iart of medial portion of dorsiil funiculi; w IT, middle root /.one. (After 1'.
riechsiK. Neurol. (Viitrallil., Leip/.., lid. ix, ISIIO, S. 78, Fig. 8.)
and not to the former. The tIe<xenerations in this disease so
well worked out l)y Charcot and Pierret, West])hal, Stri'impell,
and others, Fleehsiij^ tisserts on closer analysis show a very dis-
tinct })arallelisin with the aretis outlined from the study of the
fo'tus. In heginninjjr tahes he finds that the disease is nearly
alwtiys locidized to tlie areas designtited ])y him as the "middle
root zone " ami the " median zone " (these receive their myelin
simulttineonsly, rit/i' siijira)^ ;dl other rejjfions reiuiiining at first
intact. A comparison of the two sides of Fig. "-iSO, aiul of
Fig. :2<S1 (fu'tiil markings) with Fig. "-iSti (degeneration in
tahes) illustrates strikingly the ]nirallelisni. After tithes has
passed the incipient stage the zones which develop hiter may ho
iittacked in variable order, idthough, as a rule, the first to suffer
is the lateral portion of the dorstil root zone, together with
(ioll's fasciculi, tind hiter the medial portion of the dorsal root
zone. The ventral root zone appears to be, without exception,
the last to be attacketl.
Voii I'rcliterew ao-rt'fs in the main with the views of Flechsjo".
lie also divides tlie fasciculus ciiiie,itiis of lUu'dach into a ventral,
a lateral, and a dorsal zone, but does not oltject to the insertion by
Fi<
. as-:
Iter
niei
l>e!,'
Hell
Kij;
COl
d. t
th*
wl
zone."
»1>
of
V
^»l-^
CiUoLPINCi AN1> CHAINING TOGKTHKIl OF XKUUOXKS. 42t.t
Fleclisiff of a iiii<kll<' /(inc iK'tufcii. In voii Bcchtcrfu's IxioU (IMtJ)
tht'i'i' is some stress laitl upon diUVrcnccs in the tiiiu- of lucdiilliitioii
of certain portions of the faseiciiliis {gracilis of (roll. Tlie lii'st por
tion of tliis fascieulus to become nieduUated, accordin^ito iiin>, is that
immediately adjacent to the m<'dian sei)tnm, an area which cori'c-
.sponds to Fieclisig"s iiii'didiir Z<nic. In aiUlition to this, he distin-
ynisiies two other systems of tihres in the fasciculns gracilis : (1) An
area. {iiii. takinLT in the major part of the fasciculns. and situated
just external to the median /one: and cii a nari-ow stripe, (jl. lyin^''
hetween tlie area, (jiii. and the fasciculus cuneatus. The latter, von
Bechterew states, is the portion of the dorsal fasciculi of the spinal
iH' hW m\V ss
Vu,. as;2.— Ci-ipss scctiiin tliniii>.'li tlif s] iiiiil oml at the level nf the third linnliar
lUTVi'. (( ir. lateral (lor^al mot >n:ic : hW. ini'iiial ilnrsal i t /mii' : .-.v.
median n)iniiarliiieiit nf the latter : mW. iiiiddle i t zone ideiiciieraled ).
heyiiiniiiK tahes: '' "'• ventral i t zone; /'>'. lateral ii.vraniiilal trael <le-
generated. (.Vl'ter I'. Kleeli.si};. Nein-ol. Ceiitralhl.. Leijiz.. Hd. i.\. is'in S TT.
Fiji. 7. )
cord, the last to become medullated. He asserts with emi)hitsis tliat
the whole of GolTs fasciculus (with the exception of tlit' "median
zone." which li<> thinks has its origin in dorsal root tii)res) is made
up of medullated axones. which tu'c processes of cells situtiti^d in
)
1
1 1 3»
' '!
\
Ii
m
\'
i5
I!
4;5(»
TllH NEUVOUS SYSTEM.
tlu' dorsal lionis of tlie f^ray matter of tlic spinal oord.* This view
is ill (lircft contradiction to the results of tlio studies of secondary
dcju'cncrations, and of those in which (Jolyi's method has been
emjiloyed ((vV/r infra). Von Kechterew further thinks that while
a part of the lihres t>f (xolTs bundle run all the way to the medulla
obkmji-ata without interrujition, another portion is interrupted and
continued ujiward only l)y the intercalation <jf other cellular ele-
ments situated in the dorsal lioriis,
Karusin, who has recently gone over this whole subject with
the same method, havinj,' a lar^-'e amount of material at his dis-
jiosal. states emphatically that sharp limitations of single regions
can not be made out. He holds that while it is true that the lirst
well-developed fibres appear in the entry zone (Ehistrdhlniignzonc
of von Leiihosseic, or roiti'dlv Wnrzclzotie of Flechsig), at later
periods tlie jirocess of myelinizatioii o«'curs ditl'usely in all direc-
tions. He concludes that only three vvell-.separated regions in the
dorsal fasciculi are to be made out: (1) The fa.sciculus c meatus. (2)
the fasciculus gracilis, and C\) Lissauer's marginal zone. He insists
that a connective-tissue sheath separates the fasciculus gracilis
from tlie fasciculus cuneatus, a finding which lie looks upon as a
strong argument in favor of the anatomical individuality of the
two fasciculi. +
As has been stated, Flechsig's publication in l.S!)(» was based
upon the study of sections made in his laboratory by Trepinski.
Trepinski himself, now at Zoppot, has ct)ntinued the studies, begun
in Flechsig's laboratory, during the pa.st eight years, and in ISllS
has written a paper,! in which becomes to conclusions which differ
materially from those of Flechsig. Leaving out of consideration
the libres of Ijissauer's marginal ztme, he states that, corresponding
to the period of myelinizatioii, there are four distinct fibre systems
to be differentiated from one another in the dorsal funiculi of the
human cord. These libre systems, the areas of distribution of
* As is pointed out further on, all the recent evidence is in exuct (ipiKi-
siti(Hi to this view of von Uecliterew. The fii)r('s of the fasciculus gracilis
((iolii) appear to l)e almost wholly intraiiicdullary contiiiualions of dorsai
root fibres, while those in the median zone almost all represent medullalcil
axones of neurones, the cell iKxhes of wliich are situated witliin the gray
matter of tlie spinal conl itself.
f There is no getting around the fact, however, that the long fibres of
the dorsal roots of the lower spinal nerves wliich enter the fasciculus cunea-
tus are continued upward in the fasciculus gracilis. Secondary degenera-
tions prove this beyond the shadow of a doulit.
X Trepinski. Die emhryoiialen Fasersystcme in den Ilinterstrangen uiid
ihre Degeneration liei der Tabes dorsahs. Arch. f. I'sychiul. und Ner-
venkr., Uerl., Md. xxx (Wdl), S. 04-81.
if'H
GROriMNd AND CIIAIXINC. TOdETHKK OF NKI'KdNES. 431
which frcqiu'iitly ovcrhip, attain to a i-i))*; coiKlitioii — that is, coiii-
l)letf tilt' process of iiiedunation in f(rtuses 24 cm., ^!S cm., .S*) cm.,
and 42 cm. loiifj. respectively. In fu'tuses of tlie last length the
whole dorsal t'liiiiciiius is fully mediillated, althougrh the tiljres of
Lissauers marf^iiial zone are tiieii only he<,nnnin<,'' to receive their
myelin sheaths. A numher of the fiffures accompanying Trepin-
ski"s article are here reproduced (Fij^s. :is;5-2!tl).
While it is true that the areas of distrihution of tiie four fil)re-
systems overla[) one another to a certain extent these can he deter-
mined by an analysis of the varying appearances presented in the
dorsal funiculi at ditl'erent stages of development.
In the dorsal funiculus of fo'tuses '24 cm. long there are many
medullated lihres present, but not everywhere in the cross section.
The dorsal i)ai't of the doi-sal funiculus (Fig. 283, a) in the lumbar
J, . • ■ ■
' ":•:•.•,■,• A'.';
1 <*
Fid. 283
(•28 cm.)
region is devoid of myelin ; tlie more vt-ntral parts (Fig. 2S;}. c) are
regularly studded with nerve fibres, but even here tlui individual
fibres are .separated from one another by considerabh> distances. In
the thoracic and cervical cord there are no medullated fibres in the
dorsal regicm of the dor.sal funiculus (Fig. 284, />), nor are there any
in (he middle region of each dorsal funiculus (Fig. 284, a) ; the only
medullated fibres present are situated in a narrow stripe near the
median sejjtum (Fig. 284, (/l.and in a. somewhat broader stripe along
the dorsal horn (Fig. 284, c). In the most ventral region of the
funiculus these medullated areas go over into one another. The
non-medullated regions are continuous with one another at the dor-
sal perijihery.
In fo'tuses 28 cm. long the appearance of the dorsal funiculi in
.'dl regions is very different from the foi-egoing. In the lumbar
cord, which has by this time grown to be considerably larger, not
only is the dorsal portion, which before was non-medullated, now
regularly studded with medullated lil)res (Fig. 28")). but the ventral
portions have many juore medullated fibres in them than before,
the individual medullated fibres now standing much closer together
!l
:1
■:
■:1,
r *'
< , '
:t:i
■W
;lf, -,
Ml
V
1
1 1
TI
um
L
4:52
TilK NKU vol's SYSTEM.
tliMii ill tilt' fd'tiis 'J\ cm. luiiy. tilt' new lilircs cvidfiitly occupying
tlif iiitt'i'isimocs iM'twccii the oltlci' ones. It is dhvioiis, tluTeforc.
tli.'it tiiis second system of lilires occiijiies tlie wliole cross section ot'
tlie liiiiil)iir portion of llie dorsal fniiiciiii. aitliouuli Trepiiisi<i stiite>
tliiit the dorsiil rejrioii of the dorsiil fnnicuhis contains more of tlie
fihres of the new system than does the ventral re<rion, for in a
fd'tiis '^S cm. Ion;,'-, the dorsal rejiioii jirevionsly entirely noii-mediil
lated is almost as thickly studded with medullated iii)rcs as is the
ventral re^.'-ion.
Ill the thoracic cord and in the cervical cord there has also heeii
a marked increase of mediillated libres when the hetiis has attained
a lenji'th of iS cm. The reijfions of tlie dorsal funiculi, which in the
fietus "^4 cm. long were noii-niednllated. are now occupied hy
medullated libres. and. further, even those re;iions wliitdi showed
medullated
HI)
'fore now contain a ffreater niuiiher of them, for
the individual libres stand closer toyether. The distribution of tin
new
lib
res in tlu' ci'oss section is. liowevei-. not even, and the cross
.section shows light areas and dark areas in \Veii;ert iireiiaratioiis.
w liicli are (juite different in distribution from those chai'acteristjc
of the previous period of develo])nient.
In the thoracic cord the lightest part of the cross section at this
stage is the middh' region of the dorsal funiculus (Fig. 2N(i. In ; it
has the form of a strijie which goes from the dorsal iieriphery almost
to the ventral extremity of the funiculus. The dorsal funiculus in
the thoracic regitm thus becomes divided into a middle light part
1 1
(- n II
Ji
r
<i
•*>■-
/^t
-■■'<:;.
■■;?'??■
X -^:
H V:
Vm. '2S((. (2S (•111.)
>.^
-M
M
•jsr
•,'S (111. 1
(Fig. 'JS)'.. /;i. a latei'al dark part (Fig. 2S(). o, and a medial dark [lart
(Fig. 2S(i. (I).
Tn the cervical cord in the ftetus i?S cm. long tlii' fasciculus ora-
cilis (Fig. :iN7. fM. owing to the small number of medullated libres
present in it. appears light, with the exception of a narrow strip
neai' the median septum (iMi
•2S7. (h
a reiiion win
ch. it will be
=x.
■?€ii
m
./
m^-:
-^w
<iUOL'lMN(i ANI» ( 1IA1NI\(J T(>(iHTIlHlJ dl" NKl'UoNKS. 4.S3
nralU'il. cuiitniiicd some iiicdulliitt'd tiln-cs iii tlu- I'm-Ius ^1 ciii. loiijf.
Tin- (liirk stripf of (loUs fiisciriiliis passes over at tlic most vciitml
rt><Cioii of the dorsal fiiiiiciiliis into the iiioiliillatcd art-a wliitdi
corresponds to tlie faseiciiliis (■imeatiis. Tlie second system of tiln'i's.
tlierefol'e. ill tlie cervical re- u
fl'ioii is distriliuted ovei' the
whole cross section, hut the
lihres of the system ai'e
nuicli mori' mimei'ous in the
narrow stripe occupyinj,'' the
medial portion of the fas-
cictihis <j;racilis, and in the
wide stripe corrospondinj^
to tlie fascicuhis ctineatns.
There are relatively few
fihres of the system sitnat<'d
in the lateral jiortion )f the
fasciculus ji'racilis.
It is thus seen that the
second system of fihres (f(e-
tus 'is cm. loiiyi dilt'ers from
the tirst system of lihres
(fo'tus 24 cm. lonj;-) not only
in the time of iiiedullation,
hut also in the arrangement of fihres as seen in the cross section.
The mistake must not be made of thinkinj; that all the fibres seen
to be mediillated in the fietus 2S cm. loiiji: belony to the second
system : Tre])iiiski"s meanin^r. I take it. is tliat to the second system
helonjj' only those fihres which liave received tlieii- myelin sheaths
duriiiir the period of <;rowtli extendiiifjf from tlu' time when the
fo'tus was "^4 cm. loii^' to the time when the f(etus is 'iS cm. lonjjf.
The third system of fihres in the dorsal funiculi, entirely noa-
medullated in the fo'tuses 2S em. lonjj:. attains its full develoiHueut
in fu'tuses 3.") cm. long-. In the fcetus 2S cm. lonff the ero.ss section
of the dorsal funiculus in the lumbar refrion was evenly studded
witli mcHlulIated fibres. In the fo'tus ',]'> cm. long- there is seen to
be one area which in Weigert preparations takes a very dark stain,
while other jiarts are stained of a light color (Fig. 2SS). This is
owing to the fact that in the dark region there has been a great
increase in the number of niedullated fibres. The new fibres (those
of Trepinski's third system) occupy on the cross section stained by
Weigert's method the greater part of the luinbar dorsal funiculus
I Fig. 2SS, (•). The area in which they are distributed is limited dor-
sally by a ciu'ved line, behind which the doi'.sal funiculus looks light
(Fig. 2SS. h). Near the median septum too there is a light stripe
(Fig. 2SS, a), which is continuous with the dorsal light region;
29
Fio. !iss.
:r> ciii.^
!!^
V,
i
iU
THE XEUVOL'S SYSTEM.
l)o.si(l(>s, tln' jurist vofiti'iil part of llio lmiil)iir dorsiil funiculus (Fij''.
ixs.f) looks Ii<,'lit in roniparison witli tlu- ilark ana, but iiciv liie
Iciiiai'cation is not sliarp.
In tho thoracic cord of a fo-tus ,'{5 cm. ]on<f there is a uicmhrr-
niont into liyht and dark areas, imt tliis uieinhei'inent. as Trepiu-
ski's drawiiij^'s sliow. is (piite ditferent from that de.scrihed in the
f(etus 'JS cm. long (cf. Fig. :iSll witli Fig. iS(l). In the fo'tus .'55 cm.
long only tlie more ventral part of tlie latei'al portion of tlie dorsal
funiculus (Fig. ^S!», o is dark; the dorsal poi-tion of the lateral
region (Fig. 2H\), b) appeai-s now to he light, although in the iVetiis
2H cm. long it was just as dark as the ventral poi-tion of this latei'al
region. Fui-tlier, at this iieriod (ftetus I!.") cm. long) the lateral dark
region is considerably broader than it was at the earlier jieriod
^4'f^ ^^■■'■
s> ^'.''r:
I'lc. ssn. i3.T (111.)
"->^
Fi(!. ^iin. i;?.-) ciii.'i
(f(etus "JS cm. long), so that the outer dark region now includes the
middle light sti-ijie of the earlier developmental stage. The medial
dark part (Fig. '2Si). <b in fcetu.ses .'{5 cm. long consists of a nari'ow
stripe situated near the median sejitum. a stripe which at the ven-
tral end of the dorsal funiculus goes over without limitation iiiti>
the lateral dark area. The latter does not. however, reach tlie
dor.sal periphery. Owing to the narrow limits of the medial dark
area there is a much more extensive light area (Fig. 'JS!I. a) in the
thoracic cord of f<vtuses .').■) cm. long than existed in fcetuses 'iS
cm. long.
In the cervical cord of fcetuses :?.'> cm. long the third system of
fibres is distributed in the greater jiart of tli(> fasciculus cuneatus
(Fig. iilll, c). only the small dorsal portion of the same (l''ig. 'J!l(i. /<i
showing no increas<> in fibres : this dorsal jiortion is now of a light
color, although in fo'tuses 'JS cm. long it was just as dark as the
more ventral portions of the fa.sciculus cuneatus. The fibres of the
UKoriMNd AND ('IIAININ(} T0(H>:THI:I{ of N'Rl'HON'KS. 435
tliinl system an' (listi'il)uti'(l also in tin- medial portion of the fascic-
ulus j^raeilis (Kiff. •J'.Mi. ih, as is s1i(»\vm l>y an increase of tlie medul-
lated til>res situated there at this (levelo|imentaI sta;ie. This re^jfiou
of ({(dl's t'aseieulus is now closely studded with medullaled tihres,
aiuHooks darker than the more lat«'ral portions of this fasciculus
( Fiti'. -!•(•, (I). ( )n compai'iuy the dark medial i)art of ( JoH's fascicu-
lus in the fu-tus .'!,■) cm. lonj,'- with that of the fo-tus "JS cm. lonjf, it
will he seen that the reffion at the later period, thou^jrh considerahly
lar^^er, shows tihres standing much more closely together than in
the earlier sta}.fe. The medial dark ]»ortion of the fasciculus ^'i-a-
cilis is continuous with the dark [xirtion of the fasciculus cuneatus
at th(! ventral rej^ion of the dorsal funiculus.
The fourth svslem of Mitre;
accordiui''
to T
I'epnisKi, lias com-
pleted its development hy thi' lime the fcetus has attained a lenf,''th
of 42 cn»., for at this period, he states, all parts of the cross section of
the dorsal funiculi are evenly .studded with meduUated nerve lihi'cs.
The chanji'e in the ai)pearance of the ci-oss section is evidently (ha*
to an increase of meduUated iihres, whii'h have con\e in to occu|)y
the lijrht reffions between the Iihres already present in them at ear-
ier develo) mental .stafr*':
It
is
accordingly easv to deline the
areas of di.sli-ihution of the Iihres of the fourth system. Thus in the
lumbar cord the nerve fibres of this system occupy the dorsal por-
tion (Fiy. "JSS. fi). a medial rcjij^ion (Fi^;'. "JSS, <»), and a ventral field
iFijj^. 'iss. /'i of the dorsal funiculi. In the thoracic cord they spread
out in the dorsal re<fion ( Fiy. "JSII, h) and tlu' middle part (Fij^-. 2S[), m
of the dorsal funii'uli. In the cervical cord they lie in the dorsal
part of the fasciculus cuneatus (Fiy. *20(t. b) and the lateral part of
the fasciculus jii-acilis iFiy'. 'J'.Xl. <n. Liiter .sta<,fes of dev lopment
sliow, according to Tre])inski, no alterati<m in the a))pearances of
the dorsal fuiii<Mili. so that he assumes that all the filtre systems are
present in f(etuses 4'i cm. lony.
At this period Trepinski could make out meduUated tihres for
the first time in the reuion of T>issauer's marfi'inal zone, an area
wliKli ill realitv iM'loiiirs
to tl
le lateral funiculus of the coin
d. V.
ven
in fo'tuses JT cm. 1
on<j
tl
le m\'<
liii d
evelojiinent in this i-e;:'ion does
not ajtpear to he com]dete. for the meduUated fibres stand much
fartliiM- apart then than in the adult individual.
Trei)inski a.ss(M'ts. therefor(\ that, l(>avinj^ out Lissauer's /.one, it
is easy to distinffui.sh in the dorsal funiculi four embryonic systems
of nerve fibres. The area of distribution in the cross section corre-
siiondin"- to each of these fibre svstems can. he thinks. b(> established
wi
1.
th exactness, in .s])ite of the fact that tiie fibres of diil'erent systems
nix up with oiu^ anotiier. for each of th<> systems when it apjiears
cads to an alteration in the ai)pearance and memi)erment of the dor-
sal funiculi. F]ach of the four systems lies, in the uppei- rej;ions of
the spinal cord, partly in the fasciculus cuneatus, partly in the
h
r ?i
1 1
■■ ii:
si
r. li^
V
IMAGE EVALUATION
TEST TARGET (MT.3)
7
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I
48fi
THE NERVOUS SYSTEM.
fasciculus gracilis, aiid since nicdiillatiou is conipktcil in the fascic-
ulus jjTaci lis at the same iK-riod as in the fasciculus cuncatus, it is
ol)vi()iis that from the study of devel(>i)nient alone (lulTs fasciculi
are composed of the same embryonic lihi'e systems as are BurdachV
fasciculi.
Trepinski, like Flechsijr. believes that the distribution of the
cmbi'yonic fibre systems atfoi'ds thi' clew to the varyini;' pictures
met with in tabetic degeneration. In his article he gives a number
of examples of cases of tabes illustrating his view. And it must be
granted that if his drawings are objective, the parallelism between
the tabetic degeneration and the stages of niyelinization is remark-
ably striking. No student of tabes, at any rate, can afford to over-
look these studies of Tre])iiiski. It would lead us too far if we
attempted to compare the findings in cases of tai>es with the findings
in the embryonic spinal cord. One example from Trei)inski"s article
Fi(i. :2itl.
may. however, be given. In i case of l)eginning luml)ar tal)es Tre-
pinski found, in addition to a degeneration of Lissauer's zone and of
certain i)arts of the gray nuitter of the cord, a moderate degeneration
in the middle region of th(> doi'sal funiculi (Fig. 201. o. The dorsal
parts of these funiculi (Fig. ^'M. I» look healthy, as do the medial
regions connected with the dorsal i)arts aiul lying close to the me-
dian .septum (Fig. 2'.)1. a) and a ventral field i.i the dorsal funiculi
(Fig. 2\)\,f). This distribution of degenerated fibr<>s in the dorsal
funiculi leads to a Jnembennent. reminding one innnediately of that
met Avith in the s])inal cord of a f«rtus 35 cm. long (cf. Fig. 2SS),
with this difference, that the i)ortions which wiM'e of a light coloi'
in the f«ctal dorsal funiculus ai)pear dark in the diseased cord, and
rice rema. It will be remend)ered that in the fietal dorsal funicu-
lus this special appearance was brought about by the ripening of
GROUPIX(J AND CHAINING TOGETHER OP NEURONES, 437
tlie tliird sj'stein of fibres. Tivpiiiski believes that tlie meinber-
iiieiit in the diseased cord in this case must, tlierefore, be due to the
defeneration and disajjpeailtnce of that system of fibres wliich
called forth the membenneiit in the spinal cord of the fo'tus. He
concludes, therefore, that in this case of tabes the degeneration has
attVcted the third embryonic til)re system alone. That in the de-
generated area many healthy nerve fibres remain is easily ex-
plained, for in among the fibres of the third system there exist
fibres of the first and second system. If the fibres of the third
sj'stem alone be diseased, then the fibres of the other system shoulc)
•".main over as healthy fibres in the degenerated region. He cites
a series of interesting cases which he has met with, and illustrates
them by drawings of the sections, but for these the reader must
ccmsult the original article.
1^' I
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CHAPTER XXXIII.
CEXTRAL AXOXKS OF I'KUIIMI I;HA L (KXTUIPETAL XErROXES.
{('tmtliiKi'd.)
Studies of sconndary (IpgctuTiitiiiiis — I'lxporiiiR'iitid invcstip^ations — Li'^iioiis
of single dorsal roots in liiinian bt'in^'s — Stiidics of oaso.s of transverse
lesioH of the spiiuil cord — Fibres eoiirles,Jihri'H longiies vt fUiirx rnoij-
cnuPK of P. Marie — Ascending degenerations in dorsal fnnicnli — De-
scending degenerations — 'I'iie coinnui of Schultze — Fibres eiiihi(j('iii-.s of
I'. Marie — Trioiigfe mMio)i of (Jomljault ct Pliilipiie — Flcclisig's o -al
centre — Descending septo-nnirginal tract of Rruce and Mnir — Descend-
ing limbs of dorsal root fil)res — Axones of siiinal cord cells entering
dorsal funiculi — Kxcentric position of long fibres — Ascending endoge-
nous fibres in dorsal funiculi — Ana'inic necrosis following ligature of
abdominal aorta — Fasciculus dorsalis projirius — Terminals of dorsal
root fibres as studied by Marchi's method.
The methods of studying secondary dt'genei'iition tipijlied t(>
the dorsal fasciculi have sui)i)lii'd us with a large nunihcr of
facts of the highest degree of iniportiince. In animals, if one
or more dorsal roots be cut between the spinal ganglia iind the
spinal cord, the intramedullary continuations of these fibres un-
dergo secoiulary degeneration, ami can l)e studied later by Wei-
gert's method or, better still in some cases, by the method of
Marchi. In this way it is possible to determine the exact ])osi-
tion in all parts of the spinal cord of the intrairieduUary con-
tinuations of any desired dorsal root. Without reviewing in
detail all the individual researches made in this field, the results
in general may be thus stated : After section of the dorsal root of
a spiind nerve between the ganglion tiiul the cord, both the lateral
and nu'dial bundle of fibres (seen just after entraiu'e) inulergo
complete degeneration iind can l)e easily studied. Immediately
above the level of entrtmce of the nerv(> root concerned there
is degeneration in the entry zone. If the lesion be situated low
down in the spinal cord, an examination of transverse sections
made at different levels up the cord shows two things: (1) A
438
mi
(illoriMNG AND CIIAININ'C} TOCJHTIIKU OF NEURONES. 4;5t)
2)roi,MT.-(.sivo (liniiniitiou in tlu' muiihcr of dcfjenerati'd fibres as
the cord is ascomU'd ; {'i) a gradual chaiijic in the position oc-
cupied by the degenerated fibres. Tlie first observation proves
that the fibres of a dorsal root wliich ascend in the cord stop at
different levels; the second proves that fibres, which low down
in the cord are situated near the gray matter in the entry zone,
1 igher uj) come to occupy a position more dorsal and medial,
gradually approaching (i oil's fasciculus, and in the case of the
sacral roots, for exanij)le, forming a part of it. All the evidence
from the study of secondary degenerations goes to ])rove that
the fil)res of the fasciculus gracilis in the cervical region repre-
sent the long intramedullary continuations of dorsal root fibres
which in the sacral and lumbar region were among the fi])res of
the fasciculus cuneatus. Each dorsal root as it enters the spinal
cord pushes the fibres of Burdach's fasciculus in a dorsal and
medial direction, so that the long ascending fibres are neces-
sarily successively more and more displaced toward the dorsal
mcclian sulcus. These relations are beautifully illustrated by
the experimental work of Singer,* Kahler,t Tooth,! Singer and
Miinzer,** aiul others.
Singer and ^riinzer cut the dorsal roots of the twenty-sixth,
twenty-seventh, and twenty-eighth spinal nerves on one side,
and also the dorsal roots of the twentieth, twenty-first, and
twenty-second nerves of the same side. After the aniimd had
lived long enough for degeneration to become marked, it was
killed and the degenerations were studied in sections made
at different levels (Fig. •i'.^'i). A section made just abovi' the
entrance of the twenty-sixth root shewed degenerated fibres
in the \\hite matter immediately adjacicnt to the dorso-medial
* Singer, J. Uebcr scciiiuliin' Dcgi'iuTiition iiu Itik-koniiiurk des IIiiikK's.
Sitzungsb. (1. k. Akad. d. Wissonscli.. 3Iiitli-i' tiirw. CI., :?. Abtli., Wicii, IM.
Ixxxiv (1882), S. 31)0-419.
+ Iviihler, O. Uebcr die Veriiiideruiigen, welciie sieh iin IJikkeninarke in
Fiilse einer goringgradigen roinpression ontwickoin: notist eineni die se-
I'lindiiro Degeneration ini Hiiekenniarke des Ihindes lietrulTenden Anliang.
^tsohr. f. Ileilk. Prag.. I?d. iii (1882), S. 187-282.
t Tooth, 11. H. The (Joiilstonian Leetures on Seeondary Degeneration of
the Spinal Cord. I?rit. M. .1.. Loud. (18H<(). i. pp. TW ; 82."); S,^):!. Also Re-
print, London (J. A. Churehill). 188!».
* Singer. J., and E. Miinzer. Heitnige ziir Anatoinie des Centralnerven-
systenis insliesoiidere des Iliiekenniarkes. Denksehr. der Wiener Akad.,
Bd. Ivii (1S!):J-"!)!), S. 501).
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440
TIIH NKIlV^ors SYSTEM,
surface of the dorsal lioni. At a little lii<,'iier level below the
entrance of the twenty-second dorsal root the diseased fibres
were more separated from the d(»rsal horn iind occui)ied a trian-
jxular area not so very far from the dorsal nvdian sulcus (Fi<f.
'i'.}-*, (i). These fibres were evidently those which represented
continuatif n.^ of the twenty-sixth, twenty-seventh, and twenty-
eiyhth ncive roots winch had l)eeu shoved dorsalward ami me-
dialward on account of the entrance in the interval of fibres
from the twenty-tlfth, twenty-fourth, and twenty-third sj)inal
Fig. 292. — S(M(iii(l:ir.v (IcKt'iicratioiis in tlif siiiiuil cord al't<-,' ('xiiirimciital scc-
tiiiii 111' (liirsiil roots. (.M'tcr .">iiii;<r aiMl Miiiizcr. I'mm A. van ( icliiichtcii.
Anatomic ilii sy.stcnic n( rvctix dc I'lionniic, I.oiivain. 1S!I7, ii|>. I?(»r> anil lidti,
Kifis. 20S to 212. ) (/, level of tin' twi'nt.v-sccimd si)inal ncivc ; /), cross section
of the cord between the level of the twentieth and tweiit.v-second spinal
nerves ; c, transverse section throu^'h the cord at the level of the eifjhteintli
spinal nerve ; il. transverse section of the cord in the thoracic region ; c, trans-
verse section of the cord at the level of the intuinescentia cervicalis.
roots (not cut in the experiment). Sections mtide through the
cord iit iiny level between the entrance of the twentieth and
twenty-second dorsal root showed the degenertited fibres of the
twenty-sixth, twenty-seventh, iind twenty-eighth still iiciirer the
mediid septum, itnd in tiddition new degenerated fibres of the
twenty-second and twenty-first roots just dorso-meditd to the
dorsal horn of gray matter (Fig. 20t>, //). Higher up, tit the
level of the eighteenth spinal root, the degenerated fibres be-
r
IH
GROUPIX(i AND CHAINING TOIJHTIIEU OF NEl'RoNKS. 441
lon^Miij,' to the dorsal mots wliicti had lu'cii i-ut liiji'licst up wt're
soiiH'wliat si'parutt'd from the dorsal lionis and had coiuo to
occupy the middle portion of the dorsal funiculus, although
they were still se})arated by undegenerated fibres from the
hundle of degeneratcil fibres near the median septum, the long
continuations of the twenty-sixth, twenty-seventh, and twenty-
eighth roots (P'ig. W'i, (•). The lateral bundle decreased pro-
gi'essively in size in the sections taken from parts of the cord
higher up. Sections made through the thoracii^ cord showed
an ever-decreasing number of fibres in both bundles, which now
beg.m gradually to apiJi-oadi one another (Fig. 'i'.^'i, <l). In the
cervical cord the two bundles actually fused, and Singer and
Miinzcr could see only a small triangular zone of degenerated
filires situated near the median se))tum (Fig. '^!»'-3, '■). Such an
experijuent would seem to l)e proof positive of the successive
termination of the ascending continuations of dorsal root fibres
at different levels of the cord and of the gradual and progres-
sive dis])lacement dorsalward and medialward of the longest
fibres. Experiments of this tyix' may be re])eated at will, and
they have been already made by numi-rous investigators, among
them Oddi and Rossi,* l?erdez,t Mott, J Tooth and Horsley,
Barbacci,* and Langh'v and Anderson. ||
The study of secondary degenerations has led many to the
view that in the fasciculus gracilis only the long intramedullary
continuations of the sacral, or at most the lumbar dorsal roots
are contained (SchiefTerdecker, Singer). On the other hand,
*<til(li, 11., r. Hossi. Siillc (U'gencra/ioni consecutive al taj,'lio dellc
riidioi j)c)Steriiiri ; (■(Hitrihuto alio studio clctlf vie sensitive iiel niidoilo spi-
niile. Monitoir zool. ital.. Siena, vol, i (ISKO), jip. .')r)-,18; also Translation
into French in Arcli. ital. cle biol. Tnrin. t. xiii (ISOO), pj). 382-386.
f Benlez. Uoclierclies expcriinentales snr letrajet des filires centripetea
dans la inoelle epiniero. llev. nied. cle la Suisse roni., Geneve, t. xii (18!»3),
pp. 300-316.
:j: :\I<itt. F. W. Experimental Ini|uiry upon the AfTerent Tracts of the
Central Nervous System of the .Monkey. l?rain, Lond., vol. xviii (180.")),
pp. 1-','0.
* Harhacci.O. Pie secundiiren. systematischen, aufsteijiendeu Degenera-
tioneu lies b'iickenmarks. Centrallil. f. alljr. Path. u. psith. Anat., Jena,
lid. ii (1801). S. 353-36.1.
I Lansxley, .1. N.. and IT. K. .\nderson. Notes on Deireneration result-
ing from Section of Nerve Uoots and Injury to the Spinal Cord. Proc. of
Physiol. Soc, Lond. (1804), p. xii.
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442
TIIK NERVOUS SYSTEM.
Hiistiiiii, Scljultze,* IIot'ricliter,t Hiirbacci, J and Mruiis belicvo
that the th)rsiil roots of the tlionuMc ncrvi's iirc also con-
cenu'd in the formation of the fa.sciiniliis i^racilis, Harl)a('ci even
<,'oin^' so far us to assert that the dorsal roots thr()ii<:h-
out the whole extent of the spinal cord hel}) to !)iiild (lolTs
fasciculi.
We turn with interest to the examination of the relatively
small nund)er of cases in human l)ein<,fs in which there liave
l)een lesions (tumor, trauma) of one or more dorsal roots en-
tirely or almost entirely without direct injury to the cord itself.
Let us see in how far tin- results of study in such cases are in
accordance with the findiufjjs in experimental animals. Such
cases have been reported by Lange, PfcilTer,* (i()nd)ault, ||
Sottas,*"' Mayer,^ X.ageotte,| Soufpies,! Margulics,J and I)e-
jcrine and Thomas.** These eases, though relatively few in
* Scliultzo. ni'itriitfi,' /iir Lelire vdii dciii HckuiidJircii DcjfciU'nition im
Iiiii-kt'iiiiiark ilcs Mfiischcii Mcbsl lU'iiifrkuiij^fii iiclicr die .ViiMtoiiiiu dur
Tal)os. Arcli. f. I'sytdiiat. u. Ncrvt'iikr.. Herl.. I5d. xiv (IS.Si). S. 3r)i)-;5{)0.
f llorriclitcr, v.. l'('l)cr aiifstcii^ciidf Di'^TU'ratiinn'ti dcs Kiicki'iiinarkes
aiif (iniiidlaii^e iialliologiscliauatoinisclier l'iiti'r.->iR'liuiijj. Jena. IHSIJ, 8vo.
X O/i. rif.
* I'fiilTor. H. Zwoi Fiillc von ]„"''imin,c; der imtorcn Wurzi'Iii des I'h'.xus
ln'acliiali.s (Kluinj)ko'.sclie Liiliniiiii';). Doiilsche Ztsclir. f. Nervenli., lieij)/,.,
Bd, i (1891), S. 345-!]:0.
II rioiid)ault, A. Bull. Soc. anat,. dc Par., t. Ixvi. 1891.
■'^ Sottas, . I. Siir l\''tat di' la inocllf ('■[linii'rt' dans deux cas dc conipiv.'*-
sioti d(>s racinos postericurcs. Coinpt. rcnil. Soc. do hiol., Par., !». s., t. v
<189.'}). pp. 246-248. — Contributinii a IT'tiidt' dt'sdi'grni'rt'sccnccs dc la tnoelk'
con.sr'cutivos aiix lesions des racines posterieures. Kev. de nied.. I'ar., t. xiii
(1898). pp. 290-;{i;5.
^ Mayer, f". Zur patlioloijischen Anatomic dor Kiickeninarksliinter-
striin-,'e. Jaiirb. f. Psychiat.. Eeipz. ii. Wien, 15d. xiii (l.S!»4), S. .IT-IOT.
J Xagcotte, .1. Ktuile sur un cas do tal)os uniradiculairo tdiez iin paia-
lytiipio general. Hov. neurol.. Par., t. iii (IS!).')), pp. :!:{?: ;U)9 : 401.
I Soiiqiios. \. Dogeiieration aspondanto dii faisceau do Biirdacli el dii
faiseeau cuneiform, eon.seeutive h Tatrophip d'une racine eorvieale post^-
rieuro. Cunipt. rend. Soc. do l)iol.. Par., 10. s.. t. ii (18!),')). pp. 40T-410.
% Margulies. A. Zur Eolire voni Vorlaut'o dor liinteron Winv.oln beim
Menschon. Neurol. Cent ralbl.. Loipz., Bd. xv (1896). S. 347-;551.
** Dojerino .1., et A.Tlioinas. Contribution a Toludo du tni.jot intra-ni^-
didlairo de.s raeinos postorieures dans la region oervicaloet dorsalo suporioure
de la inoelle epinioro; sur I'etat do la luoolle opinioro dans un cas de paraly-
.sio riidicidaire inleriiMiro du plexus braehial d'originc syphilitii|Ue. Conipt.
rend. Soc. de biol., Par., 10. .s., t. iii (1890), pp. (iT.'»-679.
(iUOUHNO AND CIlAIMXiJ T()(}1;tIIEU OF NHrUONKS. 443
iiuinhcr, hiive l)t'i.'n very cari't'iilly .stiulictl, in two instance's at
least, l)y Murclii's mctiiotl.* Tin' fintlings tlins far in liuniaii
cases prove tliat in man, as in experinientul aniinnls, the root
lil)res on entrance occupy a tolcral)ly wide zone in tiie fasciculus
cuneutus, just dorsal to the <,'ray matter of the dorsal iiorn, as
this is the urea whicii is found de^n'iu'rated at the level of a
diseased dorsal root. In sections made at hi<fher levels in the
cord there is, as in aninuils, a gradual diminution in the num-
her of dej^enerated fibres met with as tlie cord is ascended,
])roving that many of the root fibres terminate not only shortly
after entrance, but also in different segments of the cord as
they are passed. Kiwh dorsal root, however, contains some very
long fibres which ascend to high levels in the cord, and sonu^
to the medulla oblongata. The long fibres, as the study of the
degenerated areas has demonstrated, are very gradually dis-
placed from the region of the dorsal horn us the cord is ascended,
owing to the eutranci' of new dorsal roots at each segment As
distinct a lamellation, however, corresponding to singl" roots,
as would appear from Singer and Miinzer's experiments to exist
in the monkey, is not met with in the luunun cord ; at any
rate, in the midthoracic region there is in the fasciculus gracilis
an intimate admixture of the long fibres of the lund)ur ami
sacral roots (C. Meyer), and in the midccrvical region the de-
generated area corresponding to the sixth thoracic root (.Mar-
gulies' case) is practically identical with that for the thir(l
thoracic root (Nageotte's case) and with that for the first and
second thoracic roots ( 1 *f eiif er's cases). Still, speaking gener-
ally, it is true that in flic Jnimrtn ct'rricdl curd in its upper p;irt
the portion of the fasciculus gracilis nearest the median septum
represents the continuations of fibres in the sacral roots, the
lateral portion of the fuscicnlus gracilis corresponds to the up]ier
sacral, lumbar and, possibly, lower thoracic roots ; the j)ortion
of the fasciculus cuneatus adjacent to the fasciculus gracilis
contains the fibres from the thoracic roots, es])ecially the upper,
while the lateral portion of the fasciculus cuneatus consists
mainly of fibres from the cervical roots. Tt is probable, how-
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* It is hifjhly desirable that tiio spinal cord of aii\ uidivichial coniiiijr ti>
autopsy with such a lesion should be removed carefidly in toto, preserved in
I cn-iier-cont formalin or frcsii Jliilier's fluid, and iian.ded over to a skilled
miirologist for cxaniiualiou as soon as possil)le after its removal.
m^
>lili
i.
444
TIIK NKia'ors SYSTKM.
ever, tliat iiitlividuiil til)ri's iiuiy disohcy tliis general luw of dis-
tril)Utioii.*
Tlic cliiiugc ill the t'oriii of the dt'jrt'iu'ratcd area, as well as
ilif altoratioii in j)ositioii, is worthy of note. The case dcscrihi'd
l)y .Mar<{uli(''s may lie ilioson as (yi>ical of the chiss to which it
belongs. If the acconipanyiiig figures (Fig. "^!i:{) and their leg-
ends he consulted, the relations at ditTereiit levels above the
site of lesion will l»e clearly luidi'rstood. At the level of lesion
(sixth thoracic root) the area corresixjiiding to the entry zone
shows degenerated fibres ; the medial displacement with arrange-
ment of the degenerated fibres in the form of an L is illustrated
in the next section (level of first thoracic) ; still higher (level of
seventh cervical root) the degeiicrate(l fibres, of which there are
now many fi'wer, occu])y a triangular area, and in the liighcst
section figured (level of third cervical root) the tyi)ica! narrow
dorso-ventral l)an(l lying close to the paramedian septum is
clearly visible.
Thus far in human cases, even in those studii'd by Marchi's
method, continuaticms of dorsal root fibres into the ojiposite
dorsal funiculus by way t)f the gray commissure have not i>i'en
described, thougb some of those who have experinu'iited ui)on
animals assert that in them such fil)res exist (Oddi and Kossi.t
Loewentbal,Jl'aladino,'*an(l l*elii/zi||). The vcit careful Knglisli
investigator Mott, however, could not find such fibres in the
monkey's cord.
Th'.' studies of secondary degenerations following fniiisrcrse
Irsioii i)f fli'' nird from compression, trauma, and other causes,
while of the jrreatest service for the information thev have
alTorded concernin}; the tracts in general which ascend and de-
* Tlu> stuilics of SchiilTcr with Jhirdii's nii'tlKul (Aicli. f. inil<r. Aiuit.,
IVinn. IM. xliii) stiow this to be prol)(il)ii'.
+ Op. rit.
X Locwotitiial. X. Neuerexperimcntcll-nnutomischiT FVitnif^zurKcniiliiiss
ciniirer Pxihiicii im (tohirn uml IJiick('iimar.<. Iiilfrnat. Moiuitsehr. f. Aimt.
u. Phytii..,.. b.'ipz.. IM. x (189.-?). .S. lOS; ^iWi: 2<i!».
* Piiladiiio. ('•. Contribution aux cniinaissancos sur ie mode se ooniportor
(h's raciiu's (b)rsalcs ilaiis la inoellc I'pinirTc ct sur Ics cfTds consocutifs Tileur
resection. .\reh. itai. lU- t)iol.. Turin, t. xxii (1S!»4). pp. Ti:!-.')!).
I Pellizzi, (i. F{. Sur les (UV-'n*''*escences seeondaires dans le systeme ner-
veiix central a la suite de lesions de la nioelle et de la section de raeines
spinales: contribution a ranatornie et a la physiologic des voies eerebcl-
leuscs. .\reh. ital. de biol.. Turin, t. xxiv (1895-'i)6), pp. 80-1:54.
n
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Fid. ^!K5. — Tnuisvt TM' sfctidii iif the limiiiiii s]iiii;il imil slid
; scciiiKlMrvdi'jicn-
criitiiiiis fiillowinjj; isohilcd loidii of the sixlli tlionicic spiimi iicrvi
A. Miirfiulirs, Nninil. (Viitnil
After
l.cip/.., IM. xv. IsiHi. S. HJSimil :vi!t. Fisis.
1-4.) .\, tiMiisvcrsr sccliiiii iit the Icvt'l of the sixlli tlicmific niiit : M. Inilis-
vcrsf scctiiin at tlic Irvil of tlic tiist I liorMcic nml : ( ', trausvcisf si'ctinii at tlu-
l(>v»'l nf tlu' sfvoiitli (1 rvical nmt ; l>. tnnisviTsf .strtimi at tlii' Ivvcl of t'U-
tniiicf of tile tliird icrvical root
14
3 '* ■'
in;
TIIK NllUVors SVSTKM.
sct'iid ill tlit'conl, iiiitunilly <1<> nut yicM as siitisfiH-torv tliita for
ilciliiclions (■(iiicci'iiiii'; the intriiiiifdiillarv i-oiirsc of tlic dorsnl
root lil)rt'rt as do the " piircr " cases in which the root tihrcs
ahiiic arc injured. Still tlicyhavc su|t|)licd us witli a mass of
conlinualory cvidi'iicc of very hii,'h value, and hesides, in sudi
east's certain fi-atures are met with which demand especial con-
siih'ratioii.
Since the resi'arches of SchielTerdi'ekcr * an enormous num-
her of eases have heen studied hy many din'erent invest i<,'ators.
The individual researelies which concern the dorsal funiculi
need not l»e referred to here, since several excellent ri'views
of the status of this siil>jt>ct are extant — notahly those of
Tooth,! Uarliaeci,J Ivetllich,'* von lieuhossek,|| Schnuius,-'' and
I'hilippe.^
licavinj; out of consideration here the th'^enenitions in the
ventral and lateral funiculi of the cord, the statement may 1m'
made that after total transvi-rse lesion of the spinal cord the
d(U'sal funiculi show, in athlition to the chan<fes which result
locally from the direct insult (/one of traumatic deijeneration
of SchielTerdecker), ei'Vtain scoondary degenerations within
them, mainly tilnwr, hut to a less extent also hchm' the li'vel of
the lesion.
'IMie secondary dejjfeiieration in the dorsal funiculi (ilmrr the
level of the lesion (aseendinj; secondary def^enenitioii) varii's
accordiiii; to the sitiM)f the injury. Thus, if it he situated in
the lower |)arts of the spinal cord the dorsal funiculi will, just
ahove the lesion, he di'i,'eiicrated over almost the whole of the
transverse section of these funiculi. Sections a little hij^hcr,
* ScliiclTiTiJi'clitT, I*. I't'lit'i' UcffeiuM'aliiin. nep'ticnition uiul Avdiitcktiir
liis Uiickiiuiiiirkos. Anil. I', imtii. \m\\., etc.. IVil., 15il. Ixvii (,1S7G), S.
.Vk>. aiul U.l. hix (1S77). .S. \V:\.
t 'I'liotll, ('/'. (•//.
I Op. fit.
* Ueillii'li, !•!. I>it' iiintiMvii W'ur/flii dcs IJiU-koiimnrkcs imd die piillKi-
iogisclit' Aiiiitoiiiit' dor Tiibcs ilorsalis. .\rl). a. d. Inst. f. .\nat. ii. IMiysinl.
(1. CiMitraliH'Wcnsyst. an d. Wien. I'liiv., Leiiiz. u. Wii-ii. (iJSir^), S. l-o'.2.
II Op. rif.. .S. 2Si).
•^ .'^ciimaiis. V. Sckiiiidiiro DoirfncratioiitMi in; Ki'ickfiimark. .Articlo in
I.uliarsi'ii-Ostcriatf's Krfjol)!!. d. spczitd. path. Morpliol. u. I'iiysiol. di-s .Meu-
solu'M mid diT Thii-ro. Wiosljadcu dSOti). S. (t:?!.
Pliilippc. CI. ('oiitrilnitiiin a IVtudo aiiatoiiiiiiue ot eliiii((iii' du tabes
dorsalis. I'aris, l!S!)T.
: Ml
OUOl'I'INO AND <'II.MNIN(i 'nXiKTIIKK uh' NKriJONKS. 417
ifltT tilt' ciilnmct' of (Idi'siil roots uIjovc the lesion, show iiikIc-
ii«'?ifnit(Ml lihrcs ill the ciitrv /.one mimI lalt'ral portion of tiic
fasciculus ciiiiciitus. The /one of iiii(h';;ciicriitcti fil)rcs iii-
cn'iiHcs pro^jrcssivdy in size in sections cut at hi^^her and hi^'hcr
h'Vels, and tlie area oeenpied liy the dej,'e lie rated fihres as pro-
^M'cssively th'creases in size, and at the same time heeomes more
and more limited to the dorso-medial portions of the dorsal
fnnienl- of t he t\v(» sides, in the cervical ref^ion thedcf^cncrated
lihres are entirely or almost entirely conlined to the fasciculus
j^racilis, and if the lesions have heeii very low down (say helow
the level in which the fasciculus j^racilis coiiiinences) they will
occupy only that portion of the fasciculiiH ^'racilis adjacont to
the dorso-niedial septum. 'I'he de^'cneration in the fasciculus
jrracilis can he followed up to the incleus funiculi j^rai'ilis in
the medulla ohlontfata. Su(di tlndin^fs prove the falsity of the
doctrine of the ahsoluto anatomical individuality (d" the fascicu-
lus ;^racilis.
If the lesion, on the other hand, he situated in the upper
thoracic region, in addition to the dejreneration of the fasciculus
trrai'ilis, there may he found in specimens studied hy Marchi's
method, at a suital)le period (death within three months) after
the lesion, dejj;eiierated lihres also in the medial and dorsal por-
tions of the fasciculus cuneatus, thoU',di the lihres are so few in
nuniher that in old cases studied hy W Cijfert's method the fas-
•iculus cuneatus on ea(di side may aj)pear almost or entirely
normal, 'i'ransvei'sc lesion of the cord in the cervical rej^ioii
always results in de<,'eiu'rat ions in the fasciculus cuneatus
whi(di, thoii^di diniinishin<^ in volume, may he followed up to
tiu' nucleus funiculi cuneati of the nu'duUa ohlonjrata.
Since eacdi dorsal root, as is evident from the forej^oiii";
studit's, contains fihres of vi'ry dilferent leiifx+lis, we arc justilied
in speakin<; of "short " dorsal root lihres, " lonu " dorsal root
lihres, and dorsal root lihrt's of " intermediate " lenj^th {Jilirrs
rtiiir/rs, Ji/tffs liini/iifs, >■/ Jihrcs nini/rinirs of V. Marie, Ki^f. '■>'.*{).
'Vhv root fihres are distiii<:uishahle not only hy their len^rth, hut
also by their topographical relations in the dorsal funiculi, and
their torminal distribution in the j^'ray matter of the cord and
medulla.
The areas of secondary dejieneration in the dorsal funiculi
/ir/dir the level of a transverse lesion ((leseeiidinj>' secondary
de<.foneration) also vary in foi'in and extent accordinj^' to the
11
mi
■a*:
' \
ill i nm
^■ia
TIIK NEUVOIS SVSTKM.
level of tlie injur to the s])iiial conl.
In 1S(S;5 Si'linlt/A' * (U'S('ril)e(l a di'sct'iul-
iuil (le<ieneration in tiie (lorsal funi-
culi following; upon a lesion of tin-
eonl in the cervical region which ex-
tended downward ai)out two aiul a
half centimetres in the fasciculus i-u-
neatus. He descril)ed it as a peculiai'
" coninialike defeneration,'" and stated
that he liad found it also in two cases
of conij)fessioii of the tiioracic cord
in tile same form (level of lesion not
stated). Me also met with it in a
somewhat ditfereiit form in one case
of *• spontaneous " myelitis of the mid-
tlioracic rejxion. In a case of lesion
(•pposite the ninth thoracic vertebra,
leading to complete destruction of the
cord at this level, he found
no such degeneration, tlu'
■'tj^^^tm dorsal funiculi being entire-
I ly intact in the lumbar re-
gion. This peculiar degen-
Fkj. 3!tt. Sclifinc iif the cmivsciiiKl tcrmi-
iiiitioii lit" till' (iliro iif tlif (luisiil riiipts.
Tile lilMik I'lisil'iirni iimss (i rcpn scuts
II s|(iti:il jiMiiKlioii : tlif line i nissiiif; it
rc'iirt'scllts tile site (if scclidli 111' tlir
(lipixil rout iirisiiijr fnmi it. Tliis ilursul
rout is (livisil)ic iiilo tliri'i' imrls, I'lirli
of wliirli lolitaiiis liil'lirriilitif; lihri's;
• • • • "sliort lihri's" ti'riiiiiiiitiiii; in
(lorsul luirii : " tilins of iiuilimii
Iciiu'tli" niiiniu}; ill fasririilus ciiiU'Mtiis
Hiinhiclii to liilir iiliinjjc into Ki'ny mat-
terat liiisi' of ilorsat liorii ; " lollji
tilirrs" ti'niiinatiiijr in luuli'iis fnniciili
gracilis (Jol I i ( /'i after liavinjr asci'iiiliil
witliintlii' fasririllns ;;iarilisof till' roril.
Tlir niii'li'iis fmiiculi riiiu'ati Hnrdarlii
is inilicati'il at ('. It rcccivrs tlic li'l'-
ininal of tliosi' " lon^ til'rcs'" ami tlmsi'
■■ lilirisof iiiiilimii li'tiutli" wliiili ronic
fniui tlu'ilorsal mots of the ci'rviral poi-
tion of tile spinal roril, (Aftir !'.
Marie, Li'i;ims snr lis malailii's dc la
luoelU'. Paris, ISOa. p. 4.1, Fijt. 48. )
eration which h;id l)een
earlier (ISSO) observed by
\Vest})lmI and by Striimpell,
has been repeatedly found
in similar eases by other in-
vestigiitors. In Fig. '^Ho is
shown a degeneration of
Schultze's comma in a case
of com])ression myelitis
which S. Kosenheim hiis re-
cently studied.
The lesion was situated
in the first, second, tind
third thoracic segments, l)e-
ing most marked at the
* Schultzc. F. Bfitriigt' ziir Li'liro vmi dor siM'tiniliircti DepMioratimi iiii
Ri'icktMiinark ilcs ^MctisclitMi iiohst Hi'iiiiTkuiiiri'ii ucImm- die .Atialmnie der
Tabes. .\n.'li. f. I'syiliiat. ii. Nerveiikr.. IWrl.. \M. xiv (lS,s;i). S. ;!."")!)-;fl»0.
(Hi()riMN'(} AND ClIAINING 'nXJI-rrilHR OF NKl'liONKS. 445)
level of the second se<i;nieiit. 'IMie fl<,'ures show the ileiri'iicrii-
tioii in the dorsal funiculi at the level of the fourth, lifth, and
A
n
F.cl
(!
F. cb
Comma
-F.cs.l.
Ftc. 2!ir). — Sccoiiilavy (IcsciKM'iition in tlio dorsiil i'liiiinili Ik low a ti'imsvt'i-sc
Icisiiili due to (•i>ini)icssii ,1 111' tlici-onl; WciKi'lll'al pripiinitioii. (After S.
Koscnliiiiii. .Inhiis Iloiikins Ilnsii. Itiill., vol. ix. :mal(iiiiit!il iiiiiiil)ir, Sept. -
Oct.. ISitS.) A, level (if the fiiiirtli tlwiraeie se.miieiil ; li. level uf the tiftli
tliiiraeie segment ; ('. level (if (lie sixth thdl'aeic segment. 'I"he pdsitioii (if
the (leKeneiatiiiK ((itiiiiia of Seliultze is very evident. /■'('/.<, faseieiihis eere-
hnispiiialis lateralis, alsd dejieiieraled.
sixth thoracic segments. IJelow this level it could not be fol-
lowed. Tlie form and position of the comma in the fasciculus
ouneatus parallel to the meditil inar<j:iii of the dorstil horn of
30
>\
k
*■■> ■
i 1
I
■
1
1
i'
45(»
THE NERVOUS SYSTEJI.
^Tiiy matter is well illnstniti'd. Tlic thicker licacl end of the
coinniii is directed toward the ^xwy matter, tlie thin tail toward
tiie (h)rsal surface.
\\'hile some investifjators (Scliultze, Hruns, v. Lenhossek, Fhi-
taii, (iiese) have hehl thait the comma corresponds to descendinjj
tihres from dorsal roots, others ('I'ooth, Marie, Daxejdyerjjjer, (iom-
])ault and IMiilippe, Diifour, Iloche) think that the medullated
axones to wliicli this area corresponds represent lihres entirely
independent of tiie (h)rsal roots, and that they have their cells
of origin in the gray matter of the spinal cord itself. The
comma would, according to the latter view, re])resent a longi-
tudiiud association tract connecting ditferent levels of the
gi-ay matter with one another. On this supposition its fihres
would be intrinsic to the cord itself {Jihrcs rui/oi/e/ics of I*.
Marie).* The comma appears to have never been observed
below the level of the ninth thoracic segment rntil the recent
study of Jloche,f in which that ol)server, by means of .Marchi's
method in a case of compression at the level of the seventh
thoracic segment, followed its fibres, though the commalike
arrangement soon disai)]»eared, as far as a point between the
third and fourth hunbar segments. He was able, too, to deter-
mine l)y means of longitudinal sections what became of the
fibres of the comma. They could be followed as fine dotted
fibrils passing oblif|uely into the gray substance. In this, how-
ever, they must (juickly change their plane, for lloche could
never follow a tibril to its exact termiiuition. The long extent
of these fibres in the dorsal funiculi (through at least eight seg-
ments of the spinal cord) is, as lloche suggests, scarcely in ac-
cord with the idea that they represent descending ])ranches of
the dorsal roots. In tlie second case of compression at the
junction of the cervicai and tiioracic cord, lloche followed fibres
from the comma as low as the level of the twelfth thoracic seg-
ment. Longitudinal sections in this case showed the degener-
* Marie. P. boi;ons siir Ics iimliidics ilr la iiioellc, H. Par. (ISn2). (G.
^hlss(lIl). — I)e Torifiinc ('xoi^riu'du I'lidiiffriii' dcs li'sioiis du oimloii jKistc'ricur
I'tudic'c's conipunitivoinont dans Ic tabes et dans Ic ])cllaji;re. Seiiiaiiii' iiit'd,.
Par., t. xiv(IH04). pp. 17-20.
f Hoclie. .\. Uebor sccuinlilro Dcjiciicratitui, spccifll dcs (iowors'scheii
lUiiidols iiebst Bcmcrkunpeii uebor das Vorlialtcii dcr Kcflcxe bci ('i>ni](r('s-
sion dcs Kiickcmuurkt's. Arcli. f. Psychial. u. Ncrvcnkr., IJerl., Hd. xxviii
(18'JU), S. olO-r)43.
iH-
(iiioupiNO AND criAiNiNO toof:tiier op neurones, 4r.l
uted fibres nuiuiii^ into the nucleus dorsalis (Fig. 20(i). Maim *
advances with much reserve the hypothesis tliat since it extends
tlirougliout the whole thoracic coril, dimiuisliing progressively
m:
^ ^ -~-v
VM'J'^'' ■'
v^'M
■ 1 ■ . i
t ' ' : ;
mi
' '''.-'it '
." ■ • ■•'.■:•'■
.' .1 ■ ,1
Fl<i. 2!)6. — Tionftitudiiiiil scctinn in an almost saRittal dircctidn at the level of the
eiKlitli tliiiracic neive sliiiwinK ilejseneralcd tiln-es • 'Lc dorsal I'unieiili alter
transverse lesion. Al'ter A. lloelie, Arcli. f. ..'liiat, etc., Herl., Hd.
xxviii. ISIM), 'j'af. x, l'"if,'. S. i ((.ventral funicnlns; the dejjeneralid tilires
helonj; in part to the deseendin^ siileo-niaiKinal defeneration, in ]>art to
short jiatlis oC the t'ascienli i)ro|)rii ; /*, sni)stantia ^risea containiiif; the
nucleus (h)rsalis (larkii ; c, dorsal fnnieiilus. The de>!enerated lihres which
lie on the rijrht-hand side near the peripher.v helon;; to the path which lower
down forms the oval held of l''le<'lisi<;. The degenerated lihres fioii'K toward
the snhstanlia Krisea form, on a correspondinj; cross section, the well-known
c<imnia-shaped dejieneration tiKiire. The conniia is soon exhausted he! iw
this level, since all the lihres turn into the gray suhstance.
in volume as the cord is descended, it may htive to do with
the innerviition of tlie intercostal muscles. As a mtitter of fact,
at present its function is entirely unknown. In 181)7, at the
Moscow Congress, Obersteiner expressed the opinion that the
fibres of the comma are exogenous, and in ISihS Zappert,t work-
ing in Obersteiner's laboratory, niiide a strong pleti for the view
that Schultze's comma, at least in part, is formed of descending
liml)s of dorsal root iil)res of the upper ptirts of the spinal cord,
A set of fibres in the dorsal funiculi other than tiiose con-
cerned in the formation of Schultze's comma, though they have
lu'cn confused with the latter, degenerate downward after trans-
verse lesion of the cord. Thus in one of the cases stiuUed bv
* Miuin. b. Kliiiiselu' uiid analdiniseiie l?eil rili,a,> zui' Leiire von iI^t
siiiiiMJen Hemi[iluj,Mo. Deutseiie Ztselir. f. Xervenh., Leiii/., I'xl. x (IS'lOi,
S. l-()(i.
f Zai)pcrt, J. lieitnijjo zur abjstiMf^ciKU'ii IliiilerslraiiLCsdeLieiieralioii.
Neurol. Centrallil., I-ei|iz., i'.d. xvii (ISnS), S. 102-107.
' ( ]
. i.
i H
452
Till'] NKRVOrs SYSTEM.
IJiirbiicci,* ill wliich there was compression at the level of the
sixtii iiiid si'veiith thonicic roots, followed by death at the end
of forty days, he found just beh)\v tl.e lesion a ratlier dilfuse
degeneration in the dorsal funieuli. Lower down he found in
the transverse sections a strijje in the lateral part of the fascic-
ulus cuiu'atus on each side, while niuoli lower still tlie degener-
ation was limited to a narrow stripe along tlu' dorsal median
septum. Barbaeci assumed (almost ( 'I'tiinly erronecuisly, as
will immediately l)e clear) that the degeneration below along
tlu' septum depeiuled ujjon the waiulering ovi" toward the me-
dian line of a certain number of fibres from the comma higher
up. Tlie degeneration liere mentioned as situated near the
median septum has also been observed l)y Keijlieh f ami by
Daxenberger.J The region concerned togetlier with a peculiar
triangular field carefully described l)y (iombault and Phili])pe*
does not degeiu'rate after injury to the dorsal roots, nor does it
degenerate in an ascending direction after lesion of the gray
substance below, (iombault and IMiili[)pe conclude from their
studies that tlie fibres adjacent to the septum, the so-called
do I'Komed idles Sdcralbihuh'l of Obersteiner (those of the two
sides corresponding to t]u> rrtifnini oraJe of Flechsig), form
at the level of tlie lumbar enlargeniciif and a little below
tliis level an oval fasciculus; that b uer down in the conns
meduUaris the same fibres are gro.iped in the form of a
* Op. cit.
■f Kodlich. E. Ziir Vcrwendimg der Marc'hi'scheii Filrbuiig hci patliold-
gisclicu I'riipiiralcii (k> Xcrvoiisysteiiis. ('outrall)l. f. Norvcnli. u. I'sycliiiil.,
Cobk'iiz II. licipz., n. P., Hd. iii (1S92), S. 111-115. Sec ulso, Die liiiitLTun
AVurzola dcs RiickemiiHrkes und die imtiiol()gis<;lie aniitoinio <ler 'ral)L'S dor-
salis. Jiihrl.. f. IVycliiat., Lcijiz. u. Wieii, I?d. xi tl8!)3-"!);i). S. 1-52.
:f I)axeiil)orgor. II. I'ebpr eiiiLMi Fall voii chnjiiisohcr ("ompression dos
Ilalsniarks init besondorer Hcriicksiclitigiing der secuiidilren absteigenden
Dej^oiicrationen. Deutsche Ztsciir. f. Xorvenli., Ijcii)Z., IM. iv {18i);{-'i)4),
S. 136- 150.
* Gonibault, A., et C. Philippe, rontribiitioii a IV'tiidc des lesions systcma-
tisi'es dans Ics cordons blaiu; de la nioclie epiniere. Arch, de meil. exper. et
danat. path.. Par., t. vi (1894), pp. 365; 53S.— Note relative a la sign i Ileal ion
tie la sclerose descendante dans lo cordon posterieur et aux relations (ju'ello
affecte avec le centre ovale de Flechsig. Progres ined., Par., 2 s.. t. xix
(18!)4), pp. 255-357. — Ktat actnel de nos connaissances sur la systeniatisntion
des cordons poslerieurs de la inoelle epinis're. Semaine med.. Par., t. xv
(1H!)5). pp. IGl-lCO. Also Eng. Trans!, in Med. Week, Par., vol. iii (189.5),
pp. 433-439.
m^
GUOUPING AND C1IAINIX(J TOCJETIIEU OF NEURONES. 4r,3
triangular hyvh {/r{<i)i(/li' tnvdiau of (ionibault and l'liilii>iu') ;
and tliat tlicy boloiij^ to the association systems of the dorsal
funi(!uli, and do 7iot n-prescnt continuations of dorsal root
fibres.
lloche's study* of two cases of compression (one at the
level of the seventh thoracic, tlie other at the level of the eif^hth
cervical segment) has gone far to render our knowledge of the
fibres under consideration more satisfactory. By Marchi's meth-
od he has been able to follow the degenerated fibres in both
instances throughout the whole thoracic cord into the filum
terminale. In his second case degenerated fibres of this group
eoidd be followed through no less than twenty-three segments
of the spinal cord. These cases are so im])ortant that they
merit consideration in some detail.
In IIo(!he's first case (compression at the level of the seventh
thoracic segment) the degenerated fibres belonging to the sys-
tem under discussion, even just below the lesion, are situated on
the dorsal periphery of the cord and are entirely distinct from
those of the comma (Fig. ;^97). A little lower they approach
the dorsal median septum (without, however, leaving the dorsal
periphery), which they reach at the level of the eleventh tho-
racic segment. The fibres lower down begin to be arrangetl
along the median septum, part of them renuuning at the dorsal
])eriphcry, however, immediately adjacent to the septum until
the level of the second lund)ar is reached. From the level of
the third to that of the fifth lumbar they no longer reach the
dorsal periphery. But from the level of the fifth lund)ar down-
ward as far as the filum terminale the degenerated fibres of the
two sides form a small triangle, the narrow base of which corre-
sponds to the dorsal periphery of the cord. Tiiroughout, the
comnui and the fibres of this buiuUe are entirely separate and
distinct. They have, IToche emphasizes, nothing to do with
one another. It will be noticed that the degenerated fibres
from the third to the fifth hnnbar segment correspond exactly
to Flechsig's rriz/nnii or/ih\ and tiiat from the third to the
* Ildclic, A. Ucbor Verlniif imd Etuliufiinijswcist' ilcr Fascrn ties oviilcii
Iliiiti'rslriiiijfrcldos ini LiMidcmniirki'. Ncuml. Cciitrnllil., Leip/,., Hd. xv
(IS'.tO). S. l.'J4-ir)r). — Ucher sociindiiro nojfpneration speeiell des Gowers'st'hcu
Uiindcls, Delist I'i'mcrkiiiip'ii ucher diis ^'('l•llMlteIl der noflexo liei fompres-
sioii des Uiieki'iiiiiiirkes. Arch, f. I'syuhial. u. NervL'tdu',, Hcrl., Bd. xxviii
(ISflG), S. 510-543.
J
W' it
} I
I
ijif
454
THK XKIIVOUS SYSTEM.
I"' I
iifth siUTiil sc^mont tlioy corrcspoiul precisely to the trimiffle
median of (Joinljimlt and I'liilippe.
In Iloche's second ciise (compression iit the h'vel of tiie
eighth cervical) it was found that the lihres of the tail ot the
eoinma in the upper part of the thoracic cord are intermingled
T. via
■■^ys^'
■..> i
r. /.
■ M
T. .r.
T .ri i^feV
T. .rii.
-'i'?.?
L.i.
tJ^.:^
L. a
If •-
L. Hi.
I
L. iv. \f.'
L. I'.
1
s. a:.
f^ \
S. ir.
S. V
Flo. 297.— TIcscciidiiiK (IcKonoriifion bolow ii transverse lesion at the level (if tlic
seventh tlicinieic segment. Metlnid of March i. (.\ft<T A. Iloelie, .\rch. C.
Psycliiat.. etc., I!erl., Mil. xxviii, ISlKi. Taf. i.\, Via. I.)
I
GROUPING AND CHAINING TOOKTIIER OP^ NErilONKS. 455
i^J%.
£ft
T. a.
T. Hi
N«
•A'.ii^
T. ir.
T. vii.
''^%.
T. ij:
T. .r.
T. J-i.
'^'' ^i
:»>C>'
2*'-?^
<»ifo»
^■\
T. XII
m- "■,' 4|
I,, t".
L. 11.
C9
Xi. III.
L. iv.
L. r.
s. a.
S. III.
Fic). 298. — r)(>s('('ii(liiij; 'l''f;'''i<'i'i<lii>"H Ix'low a lesion ("('(nuin'i'ssion) of tlip spinal
I'ord at flic lovci of fill' ciKlitli ccrvii'al nerve. Atetliod of Marelii. ( .Xfter
A. Uoehe, Arch. f. I'.sycliiat., etc., Herl., Hd. x.wiii, IWMi, Taf. .v, I'ij,'. 1.)
Ij;
U
U
li
;■?!
'M
U
^llilfl
V
^
!
450
TIIK NKHVOUS SYSTKM.
(il
lii I
.f;
V
with the most vontral (tf the ^touj) of lihrcs, which lower down
are coiitincd to tlic (U)rsiil ju'riphcrv of tlu' cord, the rmfnitn
(ivdif (»t' Fh'chsi<f, and tiic fri(ni(//c mnlidii of (ioiid)aidt and
I'iiilipi)c (Kig. 'Z\)H). Thoii{j;h there is a certain (legree of inter-
minjfliiif;, the fibres iipi)ear to represent entirely distinct bun-
dles, inasniucli as lonjritudinal sections prove that the fibres of
the comma passinjj more and more ventral ward tinally terminate
by l)endin<,f into the <,n-ay substance. They do not wander hack-
ward into the dorsal bundle.
The fibres of the dorsal bundle terminate at different levels,
but apparently in greatest numbers in the lower lumbar region,
n '' ^ inasmuch as at the level of the
fourth lumliar segment there
are as many as :}5() or 400 de-
generated fibres (lesion at level
of I'ighth cervical), whereas at
the level of the third sacral
the lunnbcr has been reduced
to 1:50 or 140, at the level of
the fifth sacral to :}0 or ;55,
while below this only isolated
fibres were found (lloche).
w ' f The ending of these fibres in
Flo. :i!iit.-SiiKittal loiifritiKliiial sctiion the gray substance is clearly
at tlic level of the til'lli .siicial nerve , . ,,.
IVelil a ease „f (•olill)|-essinli of the SllOWn lU 1* Ig. '4UU.
A very valuable confirma-
tion of the views above pre-
sented is to be found in a case
of fracture of the twelfth tho-
racic vertebra, with com])lete
crushing of the cord for a
length of some *2 cm. in the
lumbar region, studied by
Bruce and Muir, of Kdin-
burgh.* As the patient died
about five weeks after the in-
jury, the case was a very favorable one for studying the degen-
eration by the method of March i. Hruce and Muir describe
* Bruco, A., mill R. Muir. On a Descending Degeneratiitn in tlie
Posterior Columns in tlie Jjunilmr-Saenil IJegioii of the Sj)inHi Cord.
Bruin. Lond., to), xix (1896), pp. .'53^-845.
^
loi'il at the level of ( '. viii. I)eK<'ii-
erated tihres stained l)v thi' nielh<iil
of Marehi. (After A. Iloehe. Arch,
f. I'.s.vehiat. II. Nerveiikr., Herl., Hd.
.xxviii, ISilt), Taf. x. KIk. ~. ' ". ven-
tnil eoliinni, free from <letreiieralioii
at this level: h. suUstaulia jjriseii,
showiii}; the cells of the central canal ;
no Kan«lion cells in this rejiion : c,
(lorsjil fnniculi clos<' to the middle
line, some of the vessels near the
middle line heint; struck. The tihres
of the triaiiKular Held ( in correspond
infj cniss section ' of this level are
hcndinK aro\inil in a slii;litl.v curved
directi(ni into tlw uray snh.stance.
The field soon becomes exhausted.
an
in;
hc
th(
\m
(HtOUIMNG AN'P ("IIAINMNO TOGKTIIHU OK NKUHOXKS.
• )(
iiiid figure accurutely the course and termination of the descend-
ing degenerated fibres with especial reference to the bundle
here under fliscussion. They .-uggest that the bundle be culled
the "(k'Hcciiding septo-niarginal tract,"
Besides the two distinct aiul now fairly sharply defined de-
scending tracts which have just been described, there is a third
group of fibres in the dorsal funiculi which degenerate down-
ward, which should not he passed over unincnt ictiicd. In Fig.
"^!I7, at the level of the eighth thoracic segment (first segment
below the lesion in Ifoche's first case), is seen a small group of
fibres in the form of a stripe along the dorsal septum in its
ventral half. This does not reach the gray matter. It has
already vanished in the section through tiie ninth thoracic
segment. In Fig. 'iUH the sanu' tihres, though in greater num-
ber, are seen in lloche's second case at the level of the first
thoracic segment, forming a field on each side of the median
line converging toward the septum. They also have vanished
at the level of the second thoracic segnu'ut (second segnu-nt
below the lesion). These fibres evidently are extremely short
(length of one or two segments).
Finally, immediately below a transverse lesion a few fibres
degenerate diffusely over almost the whole of the transverse
section, exteiuling, however, rarely beyond one segment, an area
usually spoken of as being within the limits of " traumatic
degeneration.'"
The question now arises. What is the origin of these various
descending tracts? We know from studies made by (iolgi's
method {ritie iiifrd) that fibres of two sorts descend in the
dorsal funiculi — (1) the descending li .ibs of bifurcation of the
fibres of the dorsal roots, and (2) the medullated axones of cells
situated within the gray matter of the cord. What is the rehi^
tion of each of these varieties of fibres to the different groups
of desceiuling fibres determined by the study of secondary de-
generations ? It must be confessed that at present we do not
know for certain. Dufour* supports the view of Tooth and
Marie. Studying a case of compression of the Inmbo-sacral
nerve roots, he found in the lower part of the cord the two
* Dufour. Qut'l(|U('s coiisidt'Tatious sur le fjroupeinont, di-s fibres
endoi^eues dans les confons postiJrieurs (fe la inoollc, a [jropos d'uu cas de
coiiipri'ssion des ncrfs de la queue de cheval. Conipt. rend. Soc. de biol.,
f»ar., 10. 9., t. iii (181)6), p. 449.
''t!
it'
!ili
: )
\:
.. t'
m-
458
TIIK NERVOUS SYSTEM.
l)uii(lli'H (conimti, sci)t()-niiir<,'iniil bundle) entirely free from de-
•ieiierulioii, aiitl lielieves, tlierefore, tliiit tlie fibres eiiterinj^ into
tbe dorsiil roots play no part in tlieir foriiiiitioii. He bi-lieves
that eiieb of these descending trtiets represents an association
bundle (endogenous tli)re8) of varying appearance, according to
tbe level at wliicli one ol)serve8 it, the one Ix'itig re))resente(l
by the comma of Schultze in the upper ])art of the cord, by
"cornu-commissural" fibres in tbe himi)ar and upper sacral
regions, and below the fourth sacral level by fibres whicdi he
terms the faisrmu siilro-roniminsunil /xinferieur. The second
l)un(lle, consisting in the main of longer association fibres, is
situated in the thoracic cord in tln' dorso-lateral zone of tbe
dorsal funiculus; at tbe level of tbe twelfth thoracic and first
luml)ar segment it reaches the dorso-medial angle of each dor-
sal funiculus. At tbe level of the third lumbar root it corre-
sponds to tbe Cciifrnni oiuiU' of Flecdisig, while at the fifth sacral
it becomes the Iriiimjli' median of (Jombault ajid Philippe. It
is obvious that the consensus of opinion at present is in favor of
tbe endogenous nature of the fibres of these two bundles.* Tlie
idea of llocbe that tbe shorter bmgitudinal association fibres
tend to run in the more ventral bundle, the longer in tbe dorsal
bundle, is very attractive and entirely in accord with tbe general
laAV of the tendency of tbe longer fibres to be situated near the
periphery of tbe white matter. This law, though generally rec-
ognized, has been recently very definitely formulated by Flatau.f
* It iiiust l)e poiiitod out, however, that sueh reliable observers as Dejer-
ine and Siiilier (Dejcriiie, J., et W. (J. Spiller. C"ontril)Utioii a i't'tude do la
texture des cordons posterieurs de la moelle epiiiiere ; du tnijet ititiaiiiedul-
laire des racines posterieurcs sacrecs et lonibaires inferieures. t'oni|). rend.
Soc. de l.iol.. Par.. 10. s., t. ii (1895). pp. 0'^'2-(;2H) contest the extension of en-
dogenous tihres into the triitntjlc )ne</i(iii, and von Lenhossek (op. cH., S. 2!)i{)
believed (in 1H9.')) that the middle part of the fasciculus euneatus, about the
region of Schultze's comma, anil pi'rlia])s also the field on the dorsal periph-
ery, are the areas in which the ilescending limbs of th(> dorsal root tihres
run longitudiiuilly. Whether or not, in view of the findings of iloche,
Bruce and Muir, and Dnfour in liinnan cases studied since IS!).'), these ob-
servers have altered the opinions then expressed. I do not know. The care-
fully studied case of K. SchatTer (op. rif.) showed no degenerated fibres in
the njedian zone of T""'lechsig. hut this, as Iloche suggests, may be due to the
fact that four mouths after the lesion is too late for satisfactory study by
Marehi's method.
+ Flatau. K. Das Gesetz der excentrischen [jagerung der langen Bahnen
im Hiickenmark. Ztschr. f. kiln. Med., IJerl., Bd., xxxiii (1897), S. 5r)-li")2.
OUOUIMX(J AVI) CIIAIXINU T()(}KTIIKR OP NEUUONKS. 4r,<»
Tho (Uw^onditi^ linil)H of tlic liWros of the dorsal roots nuist,
liowovcr, occupy some ])osition in the cord. Wlictlicr tlicy iirc
dilTu.scly distril)ut('d over the fiisciculii.s cmiciitus or arc limited
to the region of the eiitry-zoue or to the third <;rou)) of descend-
in;,' llhres (very short liltres) (lescril)ed above, or iinally are inter-
mixed with the endo^jeiious descending fibres, we do not know.
Serial sections in the next human case of ])ure lesion of a dorsal
root, coniin/j; to autopsy at a period suitable for study by the
method of Marchi, should settle this nnich-vexed (|uestion.
In view, thci, of the extrenu' ])robability that desceiuling
endogenous fibres rejdly exist in that part of the cord, the (pies-
tion naturally arises, An; there not also ascending endogenous
fibres in tin* dorsal funiculi ^ Such a ((uestion could scarcely
be answered by the study of degciu'rations following either
lesion of the roots or con)])ression of the cord. It could be
more satisfac^torily attacked by (iolgi's method, and Uamon y
Cajal * and v. Lenhossck f have described the cell bodies of
niMiroiu's situated in the dorsal horns whose axones enter the
dorsal white funiculi. N'on Lenhossck states that the axones
may be mixed with ascending and descending limbs of sensory
fibres. The nund)er and course of the ascending cnd(»geiious
axones in the cord of the ral)bit ciin be cx(piisitcly established
by utilizing the cxperinu'ut of Mhrlich and Jirieger.J ^lilnzer
iind Wiener* have denn)nstrated in the rabbit by this method
(tying the abdominal aorta and thus causing amcmic necrosis of
the gray matter of the hnnbar spinal cord) the course of the
asceiuling endogenous fibres of hunbar origin (Kig. 'M)()).
While the results of such an animal experiment may not
of course be directly transferred to the human cord, still it
is in the highest degree suggestive and shouhl put us on the
alert for the isolation of these fibres in human beings. It is
of no inconsiderable inti'rcst to note that the ascending bundle
in the rai)bit occupies a region in the upper i)art of the cord
* Hamon y Cajal, S. Xuevas olisorvacionos s(it)n' la estriictura de la
mcdiila csiiinal <l(? las inaiiiifL'ros. Harcoloiia (IHOO).
+ O/K cii., s. ;?.~)4-:!r)().
|: Klirlich imd Hripjicr. rcbcr die AiissclialtunK des Lciidfiunarkgrau.
Ztsdir. f. l<lin. M(>d.. Hcrl, Hd. vii, Siippl.-Ilft. (lS8:i-"H4). S. ITm-KU.
*Miiii/.or, Vj., imd II. \Vi(>nor. Beitrairc zur Anatoniie ii. Pliysiolofiic des
CentraliuTvciisysti'ms. Krste Mittli. rdicr dii> Aiissr'lialtunn; dos Iji'iidcii-
niarkgrau. Arch. f. exper. Palli. ii. Pliariiiuiu)!., Lim|iz., Hd. xxxv (18!).')).
S, 113.
!! f
Ji
400
TlIK NKUVOUS SYSTKM.
nU)n<i the mciliim scptniii, rciiiindinj,' oiu' very nnicli of the ])o.si-
tion liikfii Itv tilt' (Icsccmliii;,' Itiindli' of fiiiloj^i'iioiis fibres in tijo
lumbar cord of liuiiiuii b('in<'s.*
-t*vjf->
Fifi. miO.— Cross sci'tioiis llircm;;li llif siiiiial curd of a nilihit eleven <liiys after
(•ompressiim III' tlii' aorta Inr uiie liuiir. |)eK<'ii-.ratc(i films slaiiieil liy tlie
metlKid 1)1' Marelii. (After Miiiizer anil Wiener, Areli. I", exper. I'atliiii. u.
I'liarinal<iil.. Leipz., M. xxxv, IS<I5. Taf. ii, Kiits. H. !», ami 1(1. i A, ernss sei -
tiiin tliriiliKli (lie lllinliar eiiril al the level of t he twenty-lirih riml ; U, ernss
seitiiili thrimfih the lower tlionieie cord al the level of the twenlielli root;
V. cross seetion thrim^li the cerviciil cord at the level of the seveiitli root.
» Till! |iossiliilily of injury to the iiiilritinii of exofreiious fibres by the
conilitioiis ul' the cxperiiiiont must liere not be lost sight of.
r-
<iU()UIMNU AND ("IIAINIXO TOdKTIIKIl OP NKl'HONKS. 401
To (U)iiilutlt' tliiH part of our siilijcct, (licrcforc, it iiiiiy he
HtutiMl that S('con«liiry <l»'<,'('nt'riitioii.s [)rov<' tliiit the dorsal fu-
niculi arc couiposcd of two distinct nets of elements — (1) intni-
MU'dullarv continuations <d' dorsal root lihrcs (central j)rol' uf^ti-
tions of spinal ;,'an;,dinn cells) and (•*) incduUatcd axones of
neurones whose cell bodies are situated in the ^ray matter of
the cord. The former (extrinsic or exoj^i'ueous tlhres) miiko
up the nuiin l)idk of these funiculi, the hitter (intrinsic or en-
do<,'cnous fihres) partly descending.', partly in all prohahility iis-
• ■cndiuf;, r:iake up a small portion of rcrt-iin fairly (h'linitely
delined rej,nons. 'I'he position of the asccndini? liiidvs of the liifiir-
cuted exo{,'en<)US 1 res correspond in •( to dorsal roots of ditTcrent
levels have been tc "t "al)ly well estahlished; the topoj^raphical rela-
tions of the descen(lin<; lind)s have not yet been satisfactorily
made out. I venture to sujfj^est that all of the fibres of the dor.sal
funiculi whr)se cells of ori<^in are situated within the spinal cord
itself be included under the term " fasciculus dorsalis proprius."
This would brin^' the dorsal funiculi into a<j;reement with the
ventral aiul lateral funiculi where the fasciculus ventralis pro-
prius aiul the fasciculus lateralis proprius contain respectively
both ascending and descending intersegmental fibres of varying
length. The fasciculus dorsalis proprius would then be divisi-
ble into a ventral portion (fibres of the comma, etc.) and a dorsal
portion (Hruceaiid Muir's dorsal scpto-marginal bundle, Ober-
steincr's ihirxDiiii'ilinlcs Sxci'iilhi'tinh'l, fibres of the ('rut nun
oral)' of Flechsig, of the median triangle of (Jond)ault and
Philippe, etc.).
The filn'cs of the dorsal roots terniiiuiting at difTcrent levels
in the cord and medulla have been followed into the gray mat-
ter by means of Marchi's method, though their exact terminal
relations can be made out only with the aid of the method of
Oolgi {I'idr iiifni). The majority of fibres of the fasci(;ulu8
gracilis which reach the medulla oblongata turn in to ejid in
the nucleus funicudi graciilis, those of the fasciculus cuneatus
to end in the nucleus funiculi cuneati. Marchi's method, how-
ever, shows that in cases of compression of the cord not a'l the
fibres of the dorsal funiculi which reach the medulla end in the
jrrav matter of the nuclei iiracilcs ct cuneati. A certain num-
ber of those which ascend in the fasciculus gracilis are con-
tinued on as libra' arcuatte externa? dorsales into the corpus
Testiforme and terminate fir^t in the cerebellum, while a oer-
AUl,
m
nt
i
I
i,5
III
ti il
il
M\2
TlIK NKU vol's SYSTEM,
(iiin iiimiltcr iirc coiil iiuicil iis tiltrii' iircuatu' iMtcriuv ami can he
sci'ii (IccussatiiiLr ill tlic raplic (I"M<;. IJOl). Many <»!" the lil)n's
of lilt' rasciciiliis cimcatiis too do iw t tcniiiiiatc in tlic micici
of tlic medulla (K. Scliailcr, lloclu'). in l-'if?. '.W-i dcf^'iMienitcd
I'lii. lidl. 'rriiiisvrrsi' sccliiiii tliriiiii;li llu' iiii'iliillii iililiiii;;ala in IIk- ifjiion oI"
the ill riissalid IcimiiMoiiim (AI'lriA. Ilurlii'. Aicli. ('. I'syrliial. ii. Nii\ iiiUr.,
Iti'il.. liil. wviii, IS'Mi, Tiir. ix, I'i.i;. I.
AsiTMiliii;:
iKTMliiin l'i)lli)\viii^
IcNioii al (lir li'Vi'l III' llir m'ViiiIIi llniiaiir Mfiiiiiiil. Tin- lUnriirialiil liliiiv
lie staiiiiil lilaiU hy Manlii's iiiitln
II, lasiuuliis vinlriilali'ralis sii|miIi-
rialis ( iiiwri'si. I >i';;i'iirrati'il liliirs iViiin I he ilnisil I'liiiiriili art' miii aniniiij
till' Uliiii' arriiatii' iiilrriiu'.
Kid. 'M)'^. — Cross srrliiiii llirimf;li llii' iiiiiliilla nlili'iiKala at tlii' Icvi'l of tlic lnwrr
hair of tlir liililriis olivaris iiil'iTior I'loiii Iho saiiic rase as llic iiri'iiiliiif^
Mkimi'. 11. (iowci's' iinnillt'. {Alter A. Iloclic, Arch. f. I'sychiat. u. Ncivi'iiU'-.,
Hcrl.. (ill. xxviii. ISSHl, Taf. ix, Via. T). i
fibres coiniiiii; froni I he area representiiiii the uppernio.st end of
the nucleii.s fascii-uli cimeati can bo seen rdrinini; two btinds,
one liirninij: dorsal, the other ventral to the substantia iielali-
nosa and Iraetus s])inalis nervi triijeniini to enter the corpus
restifornie throuiih which the cerebelluiii is reai'hed.*
•Tills path Id llin c'crclii'lliim ai)|iari'iii ly i'i>rrcs(
1 1 i lit !■ rst ni iiiihlf i II li i niliiih II .
Xllllls III V
Krillikcr'
(liicci 111 the CCI'
•clll'llllll
The iiiiiTiisscil palli from the ilor.sal fmiiculi
ilcsitjiiateil liy stiiiie of tlit> (ienmiii wrilers ii
diiriii's inii/i'/,irii:fi's //iiifiTsfr(iiii//tli'iii/iirii!<;/sfi'iii. In IS!*;! ||ii;jli T. I'al-
rick. of Cliieau'ii (I'elier aiifsteiu;eii(le Deijencraliiiii ii.ieii totiiler (^tuelselniiii;
dcs l{iiekeiiiiiarlves. .\reli. f. i'syeliiat. ii. N'crveakr.. Ivrl.. IM. xxv (ISiC!). S.
^i;{l-SM). tlescrilied nlropiiy of lilires in the dorsal paM of ll,e corpus resti-
foriiie folliiwiiiir upon transverse lesion al .iiinelion of tl';- pars cerviciilis
willi the pars llioracalis of the spinal eonl. hilircs from the fasciculus trra-
eilis to the l.-'eral part of the curpiis restiforme were fiiuiid liy Marchi's
inothoil to lie (lei^^eneraleil in a case of coinprcssioii of (ho cainla equina liy
A. Souipies mill (i. Mar
slructiiin jiar compressio
SCO (Di'itciu'ral ion asciMnlante ile la moelle ; ile
lent
c lie la iiueilc i
Ic d
levul el llu cone lermiua
(;|{()UIMN(i ANIt CIIAININO T()(iKTIIKI{ OF N KlUONKS. 4(;;5
Tlic study of Wcij^crl ])n'puniti()iis in l(»iiixitii(liiiiil iiml
tfilllSVCl'SC SCCtillll IlilS slldWll llic cxistt'Mi'c of iiiMiiy liiiiitllcs ol"
iiit'tliilliitt'd iicrvo lild't's I'Xli'iulin^j Ix'twccii tlic wliitc iiiiiltcr ol'
till' (lorsiil rmiiciili iiiid the jxniy lUiittcr ol' the cord. Wlicii
llicst' were lirst observed llicy were Itclicvcd to Ix* iiicdullatt'd
iilnvrt liaviii;:; their (>riij;in in cells of the cord, and passing i'roiii
it into the dorsal white fimiculi. Miit after the study of second-
ary deijeiicral ions which i)rovcd that the niaioritv of the white
fihres of the dorsal fascicidi are in reality continuations of dor-
sal root lii)res, the belief becaiiie current that the niedullaled
fibres now uniler consideration represent mainly the terminals
of the dorsal rottt tibres themselves, rnnnin^MU to end in the
{jriiy matter of the spinal cord. Kxhaustive and exact descrip-
tions of these medulhited libres wen' jjjiven by various invesli-
fiators who studied Weij^ert specinu'ns; the course of the bun-
dles, their arranj^cment in "i'roups, ami the rflative size of tin;
individual liundlcs have been known for a lonj,' time. Kven inon^
had been made out. (ierlacli, for example, had mentioned the
entrance of bundles of tibres from the dorsal funiculi into the
ventr.'d horns,an observation which was coidiruu'd by W aldeyer,
I'Mechsiir, and others. \'on Krdliker described t he termination
of manv til)res fi'om the dorsal funiculi in the nucleus dorsalis
(Clarke's ffray column), iiiid von Lenhossck had called attention
to the relation of the dorsal root iibres to the dorsal white com-
missure. .\s we shall see, these descriptions, so far as they were
])urely object ive, still have their value. They contain, however.
I'rcssf tiuMJ.. I'lM-. (IS!I.")), |>ii. T.V-TH. Sec also t he iiilcri'sl iiij.r cfisc icconlcil hy
F. V. Soldor. Xcun.l. CcmI nill>l., I-fip/.., !{<!. xvi (IM!t7). S. :«>«). F,(liii-:cr as
early as ISHo (/iir Kciiiilnis ili's Vcrlaiif's dcr IliiilcrsI raii,i,'l'ascni in dvi-
Mi'iliilia lllllonl,^•lla iiiid im imtcrcii Klciiihiriiscln'iikcl. Nciinil ('ciilrallpl..
bfi|./.. 15(1. iii (ISS.-)). S. r:i-7()) liiid slated tliai a few lil)res pass dire<'t ly from
Ihe fascieidiis f,'racilis an. mid the peripiiery of the cord as lilira- areiiata-
externa' dorsales to enter llie corpus restiforrne. The direct tenidnalion of
axoiiesof dorsal root lil.res in the cenlielhini .'f the same side s.'ems to he
hetter estnhlislied for man tiiaii for animals. The stndy of I'Xperinwntal
depMieralions l)y Marclii's method in animals liy such carefnl oliservers as
SluMTin!,'ton ami Mot I failed to revi'al lilaek(Mied liliivs beyond the nuclei in
the ini'didla. (See Sherrinu'lon. ('. S. Note on the Spinal Portion of some.
.Vscendini; Dci^eiicrat ions. .1. I'hysiol., ('aml>rid,e:e, vol. xiv (IH!»;!). pp. 'Jrir>-
'.Wi; and Moll. !■'. W. Fxpcrimental Impiiry upon the AITcrent Tracts of
the Central Nervous System of the Monkey, itrain, lioml.. vol. xviii (IS!!")).
I.p. 1-20.)
t'
S(
464
THE XEHVOUS SYSTEM.
where objootivity was neglected, msiny gnive errors which hud
to be corrected by means of stndies made after the metliod of
(iolgi. In tlie liglit of the newer results, however, these older
descriptions are by no means devoid of value. They can now
be correctly interpreted, and indeed a combiiuition of the
results of studies by (Jolgi's method with those belonging to
the older techni(|ue alone p<. rmit us to understand satisfactorily
the anatomical relations of th's portion of the spimil cord.
!■ '
('IIArTKR XXXIV.
( KNTTIIAL AXONKS OK I'KRIPII KKA L CKXTKIPKTAL NKl'RONRS.
{(.'ontunitf/.)
The (lorsiil root fihros as studied by Golgi's inol luul — Y-sh(i[)od bifu rent ion —
Ascending limbs tind descending limbs — Collaterals and terminals.
XowiiKUK, porh.'iTts, ill the iutvoiis system lias tlie applicu-
tion of Golgi's nic lu'eii of groiiter service tlian in the study
of tlie spinal eoru elf. (iol<ji's * early studies of the cord,
which are of the very highest importance, were so(m followed
by the epoch-making contributions of Ramon y C'ajal,f von
Kolliker,! van Gehuchten,* von Lenho8sek,|| and Retzius.'^ An
excellent epitome of the newer work on the spinal cord is to
be found in tlie tliorougli article of I'elaez.^
The chief results atforded by the study of (iolgi pictures of
the intramedullary continuations of the dorsal root fibres may
briefly be sunmied up as follows :
(1) The fact has been completely demonstrated, by way of
direct observation, that the majority of tlu' fibres of the dorsal
funiculi represent continuations of dorsal root fibres — that is, of
the central prolongations of spinal ganglion cells.
* (iolgi. ('. Studi istologici sul midollo siiinidc Arcli. itiil. [i(>r Ic inal.
uei'v., MiliiMo. vol. xviii (IH81), pp. 1 "),■)- Ki,").
t Kiunon y Cnjal, S. ('ontribiK'ioii al estiidio <](> la estruclura de la
mi'diila (■si)inal. i{uv. trimest. do liistol. (IHSi)). No. ;i y 4.
X von K()!liUiM\ A. reborden feineren Maudes IJiickeiunarks Sitzungsb.
d. phys.-med. (iesellscli. zu Wiirzb.. IHflO. S. 44-56.
* vail Geliiicliten. A. La moclle epiniero ct Ic cervelet. Cellule, Lierrc
ct i.ouvaiii (1H<)1).
II von Lerdiossok. M. Op. rif.
^ Ketzius. C. Biol, rntersucli.. Stoi'kliolm, n. F. (18!)1 and IH!):?).
l*elaez. P. L. Analoniia normal de la medula espinal liumana y algunas
indieiieiones de anatomia comparada sobrc el ndsmo organo. Madrid (18!)?),
569 pp., 12mo.
;}1 465
V
i I
m
466
TFIK NERVOUS SYSTHM,
(2) Tlio dorsal root fibre luis been sliown to divide by Y-
sbiipcd (livisio!i soon after entrance into the cord into an
ascendiiifj and a desc('n(lin<jf limb,
(;{) Tiie limbs soon assume a perpendiculardireclion, the de-
scending one terminating, after a abort course, in the gray
matter of the cord, the ascending limb running usaally for a
mnch longer distance in tiie white matter before termimiting
in the gray matter of the central system.
(4) In its course each tibre gives oil' a large lunnber of col-
laterals, so that each central prolongation of the spinal ganglion
cells comes into conduction relation with neurones of the cord,
not only in the region where its fibre terminates, but at many
levels in the cord where its collaterals end.
(5) The nuijority of the meduUated fibres seen in Weigert
specimens entering tiie gray matter from the dorsal funicnli
represent, not the terminals of the dorsal root fibres, but collat-
erals given off by the ascending and descending limbs during
their course.
(()) The terminals and collaterals of the dorsal root fibres
which enter the gray matter end there among or upon the cell
bodies and dendrites of the nenrones of the cord. They are
never connected otherwise than secondarily with cells, or with
dendrites, or with collaterals or side fibrils, or with the branches
of axones of cell type II.*
(7) The number of collaterals given off by different portions
of the continuations of the dorsal root fibres varies, and as a re-
sult the different areas in the dorsal funiculi do not agri'C as
regards their richness in collaterals.
(8) (ireater precision has hcen reached in determining the
exact conduction relations of the various groups of fibres in the
dorsal fasciculi to definite groups of neurones within the spinal
cord. (Ventral horn cells; cells of nucleus dorsalis, etc.)
(iolgi preparations show that oti their entrance into the cord
at the dorso-lateral sulcus the dorsal root fibres plunge in directly
medial to the marginal zone of Lissauer, wh(>re the axones are
seen to be grou])ed into two more or less definite portions, a lat-
eral group of delicate axones and a medial grou]) of much coarser
axones. \ ery soon after entrance each fibre divides by means
* Tlie f( \v ('('iitririifrnl fibres of dorsal roots iiicl witli in nuiny iinitnnls
fdrin an I'XL'pption to this rule. They have their orij^in in cells in the coril.
GR()UlMN(i AM) CHAINING TO(}KTIIKI{ OF NKL'RONKS. 4(;7
of ii forklikc, Y-sliapcd division ut an aii<,de between loO' and
1(!()° into two divisions, an ascending' and a descendin<i- Itraneli.
Wliile (iolf^'i asserts tliat Y-shaped division is tlu" ex(ei)tion,
not the rule, Ramon y C'ajal, von Kollilvcr, von Lenliossel<, and
van (iehiK'hten have never met with fibres whieli do not bifur-
cate. A sueeessful (lol<,n ])reparation studied in lonj^itudinal
seetion tlu'ou<di the zoiu' of entrance is verv conviiicinir ( Ki<f.
;J03). The line libres of the lateral bundles undergo V-shajJud
Fui. 303. — Kiitntnct' of tlic tilncs (if the dorsal roots into the doisil ruiiiculiis of
llic spinal cord of an ciiiliryo calf. ( .M'tcr .\. van Ocluiclilcn, .Xnatoniic du
systcnic ncrvcnx dc riioninic, Loiiv., 2. cd., l.Hi»7. p. :5(»2. Kin. ^'0,").) .\ stem
fdirc, II, is seen dividing into two branches, h, h, the asccndinf; an<l dcsccnd-
injr lind>s of liifnrcation. l'"roin the stem tilirc. n, a collateral, c. is seen to
arise. A number of collaterals arising from tlie limbs of bifnr<alion of otber
libres are illustrated.
division neiirlviill iit the siime s])ot, but tlie coarse fibres of the
mediid bundle undergo division in very ditt'erent parts of the
entry-zone. In the human embryo mtiny of the fibres of the hitertil
portion divide first iifter entrance into the substtintia gehitinosa,
and these divisions in ptirt ptiss b;u'k\v;ird out of the substiUitia
gelutinosa into the dorsal funiculi agtun; certtun others of the
m
I
■ li
m
4(58
TIIK NKUVOUS SYSTRM.
divisions run up and down pcriu'ndicularly in tlio so-oallod
lon^ntudiiuil bundle of the dorsiU horn. As iv<ifiii(ls caliltrt', I lie
iisci-ndinj; lind)s iind dcscendinjj; lind)s ditt'cr inucli. N'on Lcii-
hoss(''k dcscrilics the asccndiTiif linih as hcinj; ol'tcn coarse and
thiei\, wliile the (h'S( endin*,' liinh may l)e very delicate, some-
times resc"d)linir a eolhiterul brantdi. \'on KoUiker, on the
contrary, ' not convince iiimself of any constant ditt'erence
in the t >f the two lini])s. Studies with tiie jnethod of
vital staining uith methylene blue have tau^^ht Uainoii y Cajal
that as a rule the two lind)s arc of equal thi(dvness, but that in
from ten to fil'tiu'ii per cent, of the fibres the size differs essen-
tially, and then, as a rule, it is tiie descending lindj that is the
finer.
As rejifards the course of the ascending and descending
limbs after division, this ditt'ers according as a fibre l)elongs to
the lateral bundle or to the medial bundle, and indeed varies
for the fibres of the same bundle. The ascending lind) of a
lateral fibri' runs upward in tlie marginal /one of Lissauer for
a greater or less distance. All tlu? fibres in Lissauer's fasciculus
are, however, relatively short. Some of the fibres, as mentioned
above, run upward in the white matter of the dorsal hoi-n.
The descending lind) of the lateral fibre runs oidy a short dis-
tance below the point of bifurcation before terminating in the
gray matter.
The ascending limb of a fibre of the medial bundU^ runs u])-
ward in the cuneate fasciculus of Burdach ; it may be short,
running in to terminate soon in the gray matter; or it tnay be
longer, passing up many segments of the cord before terminat-
ing ; again, it nuiy, if it form one of the longest fibres, reach
even the medulla oblongata to termimite in the nuclei of the
dorsal funiculi situated there (Fig. ^504); or it may even go past
these nuclei without stop])ing to enter the cerebellum by way
of the corpus restiforme. rnfortunately, thus far it has been
impossible to follow in sections prepared by Colgi's method a
given fil)re for a distance of more than a few segments of the
cord, but in view of the comhijied results obtained with (iolgi's
method and from secondary degeneration this statement nnist
be held to be correct.
The termimitionof the fibres has been studied very carefully.
They bend in at various levels at right angles to enter the sub-
stantia gelatinosa beyond which they divide into a nund)cr of
!'«
(JUOUIMNG AND CHAINING TOOETIIKIl OF NKUUONF':s. 4f;y
A'. Impuyliismis.
XucU'UK funiculi mnriiti. \^
Xucteun /unicnli i/nicilis. ' \k
Kadi.r clarsnlis
with ijanyliuH ajiinale.
■ Dirii.istltio
hmiiixcurnm.
Fl(i. 301. — Scliciiic iiulicatiiiK the ciiursc fiillDWcd l)v tlic ci'iitrul iixoiics nf tlic
lu'iiplH'tiil spinal ('(')itri|>('tMl lU'iinniis in tlic dorsal I'uniciili cil' tlic spinal
conl. (Alter A. van ( ichnclilcn. AnatDniif dii syslc'nic n( rvtnx dc I'lKPninic,
a. ('<1.. Lonv., lHi)7, p. '.W.i. Via. ~"*'- • <>" the Icl't side of tlic tiKiiri' arc sliown
slKirttT and longer axoncs of a single dorsal root : on tlic rinlit side the rcla-
tivc positions of tlu' liniii tilircs I'roni a whole series of dorsil roots («, h, v, </,
. . . . i) are indieated ; oidy a sin^tle eell of eaeli ^;annlion is drawn.
li
I
iM'i
ii
\'
B
470
TIIK NEIiVOUS SYSTKM.
tiiic hrimclics wliicli run vciitnilwanl, cxlmustin^ tliemselvi's l»y
imiltiplo division iiml ciidiii^f, just as do the collatoriils, in vari-
ous ri'^nons of tiic {^ray nuittcr of the cord. TlKtsc that run as
far as the medulla before terminating' I'nd in the same way in
the nucleus funiculi <,'racilis or nucleus funicidi cuiu^iti. Those
i'nterin<f tiic cereliellum are helieved to follow the general course
of tiio fibres of the corpus restiforme.
Tlio form, course, groui)iug, and terminal distrihution of tins
collaterals (since tiu'ir discovery in ISSI liy (lolyi jnid the dem-
onstration of theii' lar;;e lunnher and great signilicance by liamon
y Cajal) have been studied by nearly all investigators who have
worked with (Jolgi's method (Kig. ;{()")). As a ri'sult we have
now very dcffinite information concerning these fine branches.
'I'hey are best studied in longitudinal sections where they can
be seen arising by little wedge-shaped processes, sonu'times from
the main axonoof the spiiud ganglion cell before its bifurcation,
but more often from tlie ascending and descending lind)s which
result from the ^'-shaped division. In the meduUated fibre the
origin of the collateral ai)pears to correspond always to a node of
Kanvier. Not only do the fibres of the dorsal roots always
bifurcate at anode of llanvier, but the collaterals ari^ always
given ott" at such nodes. It is inten-sting to note that the col-
laterals have recently been demonstrated in the spinal cord by
Kamoii y Cajal * with the mi'thylene-blue nu'thod.
The total number of collaterals given off from a single dorsal
root fibre is unknown, but may ])r()bably be very large. In cali-
bre each collateral is much finer than the axone from which it
has its origin uidess we excej)t the ultinuite terminal branch of
the axone which, as von Lenhossek suggests, may not impro])-
erly be looked upon as the last collateral given off by an axone.
The collateral runs, as a rule, ahnost at right angles to the fibre
from which it arihcs, passiiig straight or m a (uirvcd direction
ventralward into the gray matter. That the cyto])roxinud por-
tion of the fibre possesses many more collaterals than the cyto-
distal ])orti()n,at least as far as the ascending limb is coiu'crned,
is made very probable by von Lenhossek's studies, since he has
* IJiunun y ('ajal, S. Ijos oolatcralos y hifiircacidiics de la.s raiccs poslc-
riiircs (Ic la iiirdula cspiiial, ilciiioslrailas con c\ a/.iil tic motii(>i)(). Rev. do
cliri., ti-rap. y farm., .Maib'id. t. x (1H!)0-"!)T). jip. .1-8; also. HI aziil dc iiu'li-
liMio t'li los ceiilro.s ncrviosos. Rev. triiiu'st. niicrog., INhidrid, vol. i, pp.
1.51-20:5.
i.
GROriMiNU AND CHAINING T()(JI<:TIIHil Ol'^ NHUUONES. 471
never heeii iible to discover ('olljitcriils foiniiisi olT from the fil)re8
e.m.stitiitin^' the faseieiiliis jfnicilis.* 'I'his iiieiiiiality of ditVer-
I'lc. no."). — Cross section throii^'li llic si)iii:il cord of n iicwl)ori> hnlic, to show the
collatciiils. lAI'IcrS. liaiiion y (';t.iiil, Arcli. f. Aiiiil. ii. I'liysiol., Aiiiil. Abtli.,
ISOIJ, S. :«S, Via. 3.) .1. siiicus' vcnlnilis; />'. |h ricclliiliir luiinclics of llic
colliitcriils (Voiu the vciilnil I'liniciiliis ; ('. <'oll:itcnils oC tlic vciiti'iil com-
inissiii'c; />, ilorsal luiiidlc of Ilic dorsiil coiiimissiirc : /•', middle Imndlc of
tlic dorsal coiiiiinssmi' ; /•'. vcnl rai liiiiidlc ol' I lie dorsal coiiiniissiirc ; '1', liliril
Imndlcs of llic dorsal riiniciihis wliicli arise iVoiii ils simiinil : //. seiisori-
iliotoror rellex collaterals; /, Waldeyer's "mudeils" of the dorsal liorii ; ./,
iiiicU'ils (lorsiilis (iarkii receivilif; a distinct Kronp of collaterals.
ent portions of tlie llhre as re<^ar(ls tlie ori<j;iii of colhiterals in
all probability explains the varying richness of the dilTerent re-
* Tn contrast with von TiOnhossek's stMlcmcnIs mayhciiieiitioned tho flnd-
inj^s of SchiifFer (Iieilrac; ziir llistoingje del' .secuiidiiren heifeneralion ; zii-
flh'ich uin Hcitrag zur lii'u^konniarksanatoniip. Arcli. I', niikr. Aiiat., l?onn,
Hd.xliii (1S!»4). S.SjV'-'^CO). wlio found liy IMarelu's method dci^fiicrated tiiiivs
e.Ktendini; from tlic level (tf tlie lower tiioraeie cord all t he way up to llio
nipihdia in the faseiciihis eunealus frivin<;(dl' at all /ccc/.s degenerated collat-
erals which radiated into the ventral horn.s. Il is jierhaps jios.sihle that lie
has mistaken terminals for eollateral.s.
1!
is
I?
if
I*
il
IJjHjri
im
472
TIIH NKiaors SVS'I'KM.
gioiis of the dorsal funiculi in collutcnils \viii<'li is shown in both
tnuisvci'so and loiij^'itudiiial sections. Tlic ;,M'oii|>inj: of the col-
laterals ill aiiiiiiiils shows sonic minor dilTerciiees from thos(»
found in liuniaii specimens. According to von Lenhossek, wiioso
A ^mm = K<>(l.
B — TT HIack.
E .. - Uroxvii.
f -. = (ircfii.
Fl(!. 3<)(>. Schiinc lit' tl>'' stnictui'c iif tlic s)iiiiiil ('(Hil ; nerve cells shown in the
left liiili'dt' tlieciirtl; eollaterals sIkpwu in the rifilit liiilt' of tlieecml. (After
M. von !,enli(issek. Der feineri' i'>au lies Ni rvcns.vslenis, <'te., !.'. Anil., lierl.,
ISit,"), Till', vi. I i,eft half cif the curd, hlack cells are nintiir; siile tilirils are
seen arising frimi their axuiies: red cells are tantonierie nennmes. theaxones
fioins; t(p the venlral ami lateral fnniciili. .\niiin}r these are the ci'lls in the
nnclelis ilorsalis and sunie <'ells in the suhstantia Kelatinnsi of l>olan<lo;
collaterals are coming oir from the axoiies. Violet cellsare conimissnral cells
or heteronieric neurones; one is seen sendin<; its axone into the j;ray siili-
stance of the otlwr side : the <pthers send their axoiies into the white matter
of the ojiiiosite side. The firecn cells send their axoues to the dorsal fnnicnli.
In hltlc is seen represented a (iolfji eell of Tyiie 1 1, or dendraxone. In the
rijtht half of the cord the hlai'k cells represent the cell liodies of peripheral
sensory neurones situated in the f;anj;lion spinale; their central prolonga-
tions are shown euleriu}; the spinal cord as dors;il-ro(it tihres. w liich hifunate
and scud collali'rals to terminate in various parts of the suhstantia f,'risea.
Thus the reflex collaterals are --een K'liufi to the v<iitral horn: other col-
laterals enter the nucleus dorsalis; some pass through the <lorsil i-onnnissure
to the dorsal horn of the opposite side. The red collaterals come from the
white til
in the ventral an<l lateral funiculi; the lilac
pllateral
S heloUK
to the axones of heteromeric neurones; the hrown collaterals and ternnnals
represent lihres from the fasciculi <erehrospinales or pyranddal tract. /,
fasciculus cerehrospinalis vcntndis; J. fasciculus ventralis [iroprius; •?, fa.scic-
ulus ventrolatenilis (iowei-si
fasciculus cerehellospinalis
fasciculus
11 ri'hrosi)inalis lateralis; ti fasciculus lateralis proprius; 7. funiculus doi>i;ilis ;
li.r., radix ventralis; A'. </., radix diuxiilis; <i
Kan^dion spinalc.
(}Il()lTIMN(} AND CIIAIN'IN'I! T('(!KTm;iJ (»F XErUoNES. 47;}
cari'ful Htudics of 1 he conl liiivc fiirnislicd us wit li 11 wcullli of duta
coiuioruiuf? tlii'in, tlie colliitcmlrt in hiirniiii hi'iiif^s iiuiy ]w classi-
tit'd iis follows (Fig. ;)()<;) :
CoUdfcnils riiihiKj in Dorsal IfoniH iiinl Midillc I'dif nf Sidi-
sfdiifid (Irixcii. {(1) Meridian hiiiullcs passiiiy tliroiiyli l^•i!lrMl<>"s
.sid)stiiiu-(> (not iiiciiidin;;' tlios(> wliicli nw most nit'dialiy placed and
wliicli are rellex collateralsi. These {jive rise in tlie <;ray inatler to
tliat fine complex of delicatti meduUuted llbres known in tlu' hihli-
o^n-apliy as '"Waldeyer's inielens of the dorsal horn." Tlie}-
prohahly stand in conduction iclation to the small nerve cells silu-
jited there.
ih) Collaterals ai'isin<,'' from the fasciculus cuneatus medial to
Kolandos suhstance from the same area which {j^i ves rise to the rellex
collaterals (ride hifrd), althouj,'-h much less numerous than these.
They turn transversely hiterahvard to ternunate in <'nd-arhoriza-
tions amon<i: the cells of the central part of the dorsal horn.
(c) Collaterals from the most ventral part (»f tiie fa.sci<'ulus cune-
atus passinj; into the dorsal liorns. These stain brown with (Jolffi's
method, (juite diU'erently from the other yi'onps of collaterals. They
go |)ast the mudeus dorsalis but enter into no I'clation with its ctdls.
(<l) C-ollaterals which end in the substiintia <,''elatinosa of Ro-
lando, few in mnnber and extremely line. Orijrin not clear.
Collafenils cikHikj in Vciitntl Hoviis of iivdy Matter. — This
{froiip incdudes the majority <if those ii'i'egulai* himdles seen in \V(>i-
gert .sections pa.ssin;i: in from the cimeate fasciculus of i^urdach
partly v«Miti'o-medial to tlM' substance of Kolando. ])artly through
the medial half of this sub.stance, foi-ming S-shaped curves in the
gray substance and passing ventralward directly into the ventral
horns {Al>scfni ii rii ii()sl)ii ndcf of Scdiwalbe, Bo(/fiibi'ni(lfl of ]{ed-
lieh). These bundles are largest in the intumescentije of the cervical
and lund>ar regions. They arise always in the si(d<le-.shaped licdd
of the fasciculus cuneatus in the region before si»oken of as the
"entry- zone." * The c(dlaterals of this g-rouj) are the largest in tlu^
human cord. They can be divided into two subgroups: (1) The
main mass passing in fanlike convei-gence from \\\o fasciculus
cuneatus into the gray substance through the narrow space just
ventro-nunliid to the medial angle of the sub.stantia gelatiiu)sa of
TJ(dando, inuuediatidy behind the jioint of bending of the margin
of the dorsal horn. They are joined here by the second group, (2)
* Pierrot's fiandde/les p.rtcnicx; Striiiiipcirs Wiirze/zoiii' ; Wi'stpliul's
WiirzdciutritfHZoni' ; von Hcclilercw's GrundltHnilt'In (hr IIinli'r.strHnye ;
PI('olisii>;'s riirdt're Wurzelzone ; von Lenhossek's KiiiiitrahluntjHZO)ie or
Rvflnxkollaceraleuz" 11 e.
%'\
-ii
V
iiff-'
■i , i
474
TIIH NKllVors SYSTKM.
coiisistitiif of a muhiImt <»1' IhiimIIcs less closrly arrniiyrd wliicli iiriso
iicaivr tli<> point of ciilraiici- of tlir doi'sal roots into tlit' coi-tl in ||a^
lateral ri'vrion of tlir fasciculus ciincatUN dorsal to ItolatitloM sult-
stanct'. Tlicy liavc to pciiclralr tlic snhslanlia ^clatiiiosa l)(>foi'(>
uniting with tlic main ir>'<»i|> ventral to tliis sulistanee. All tliese
collaterals {Ri'jlr.fliolldtcndi'ii of von KolliUer, Miiiiojo sciisifirih
innfrr of Kaiiion y C'ajal) spread out into the vi>ntral horn, calyx
fashion, and exhaust thenisel^'es hy nMilti])le division in ainoii;,'' tiie
cell hodies, dendrites, auil side lil>rils of tlie lower motor neurones.
< )n their way forwai'd they {five oil' side twiys which eoiiie in con-
tact with cells of the dorsal horns. The curious hehavior of theso
collaterals in the mouse and rahhit where the contact rela'ionsare
maiidy willi the side lihrils of ventral horn cells luiH been referred
to above (Section V). iiethe's •" fundamental experiment'" (.see pa<,'e
27'J) is also interesting in this coiiiiection.
Colhttevah v)i(Jiiit) in flic XiicIchh Dorsith'n (Cliirkii. Stillin-
(//). — This vei'v im|)ortant yroup of collaterals has its origin exchi
sively in the middle area of the fa.sciculus cuiu'atis, never from the
fasciculus {jfracilis. The dark color of Clarke's inudeus in Wei<jferl
speciuu'us is due to the preseiu-e in it of larye numbers of niedul-
lated collaterals (and terminals) of dorsal root libre.s. The btnidles
of collatei-als i)ass into the ;;ray matter and reach the dorsal side of
the mudeus, where they split iido t wo division.s, on(M)f which pa.sses
to each side of the nucleus, so that in cross sections the nucleus re
miiuls one of a berry on a stem oi-, if one will think of the structure
in three dimensions, the long- nucleus dorsalis can be thouyhl of as
a lo;^- lyiny in a ti'ouj,''h. They form by their iuultiph> divisions
baskets about the indivitlual cells of the nu(deus, eacdi lil)i'e comins,'
into contact with the bodies and dendrites of sevei-al cells. In be-
{finninjf tabes, specimens stained by Weijjcrt's juethod often show
that tlies«' lino feltworks of medullaled collaterals in the nucleus
doi'saiis a-e, along with Lissauer's nwirginal zone, the first elements
to disappear.
ColUitcmh t/oinr/ into flic Dorsal C<)))imiss)()'r of the Siiinal
Cord. — The dorsal commissure in most animals is made up mainly
of sensory collaterals. \'on rienho.s.sek states that in human bein<rs
it is composed exclusively of such libres. They have their ori<;in
in the mo.st venti-al i)art of the fasciculus cuneatus on the dorsal
border of the jffray commissiu'e. They ajjpear to end in the o])p()site
dorsal liorn, spreadinji' out in a bu.shlike fashion veidral to the
medial portion of Kolando's substaiu-e, where they break up into
entl arboi'i/.ations.
No collaterals from the doi-sal root libres or dorsal fasciculi have
flI{OlMM\n AM) CIIAFN'INd TOCiiymKIl OK N'MI'IIONKS. 475
bci'ii tPiict'd tliroujrli lli(« voiitriil i-oniiiiissiirr.* Wliatcvcr ilirrrt
dcciissation occurs in tlic (Imiiiiiii of the |)cri|>licriil Nciisory iiciii'onu
is nccuimlcd I'di-. tlHTcI'mt', hy tlic sciisorv cfillittcrals foriniiiy; the
(lorsiil <'t)miiiissiii'c. Tliat siicli a I'ccMc mass of lil>rcs can accomil.
for tlic sensory (It'ciissatioiis ol" die pliysioloyists no one can su|»-
j(osc. Tliis scnsoi'y dcciissalion must nnicli rallicr lie explained,
tlierefore. l)y the assumption ol' crossing,'' of the axones of centripetal
ueurones of the second older or of hi<^her orders (ride iiifiui).
As to llie actual Ivnniiidls iif lliv ii.nnirs of the dorsal root
filires, they heiuivc just us do the coliutenils runuiiij^ in to eml
in the dilTereiit portions of tiu' ^'niy mutter of the cord and
nu'duUa. There is an important ^'ap in our kuowledj,'e in one
particular. \\ f (h) not certainly know as yi't whether or imt
the terminals of lilires of diil'ercnt lenj^^h have spccitic, thut is
to suy non-homologous, end stutions. Should the utlirnuitive ho
proved, the imi)ortunce of such u fact for physi()lo<j:y uml im-
tholojry is ohvious.
We iiuve now described the spinal peri})heral sensory neu-
rones as fur us they ure known in their entirety, including,' th((
bodies of the spinal f^anfflion cells, their peripheral prolonj^u-
tion, the nerve endin;;:s on the surfuce of the body and in the
oriTuns, and finally the central prolon<,'ations of the s])inal fj^an-
glion cells, their ^'-shaped divisions, the course und termination
of tlio asconrtiug and descendiiifj limbs, as well us the orifjin
und dlstribuHon of the colluterula givi.. olT from their vurious
parts. When we Lhink of individual neurones of this f,n'oup,
for evample, a neurone correspond in jj; to one of the sacral roots
whose pcri])hcral process collects throu<^h a lar<>(' number of
divisions impi'essions from the lower extremity, perhu])s even
from the sole of the f<iot, while its central prolonj^atioii, leuvinj?
the spinul <;aii^lion and enteriu.i,' the s])inal cord in the lum-
bar rej^ion, jjives oil' collateral branches to the nerve cells in the
cord of thut rej^icm, while its muin usoendinsj division passes
up throujrh the wliole leiifjth of the s])inul cord to tormimite in
the nucleus funiculi f,n*acilis of the medulla oblonguta,t f?iving
* Minpazzini (Sulln fuia strattura dol inidolio spinale di'll' uoino. Hiv.
spor. (11 froniat., Hofi^io-Kniilia, vol. xviij (1802), fasc. 11. Fiij. i) has iiicturcd
('"llalcrals wliicli lie assunn's to l)t> sensory passinj; tliroiinh llic vciiti'al coni-
iiiissuiv; Init v. Lt'idiossrk iltMiics llic cxislcnce of any such fibres, and
V. Kiiilikcr agrocs with him.
t Possibly even in the cortex of tlio forebelluai.
m
1
i.l.
(I
iT<;
TlIK NK1{ vol's SVS'I'KM.
oil' t>n its \V!iy very iiiiiiiy i'ollMtcnils to very (lilTcrciit sc^iiiciils
(if tlic cord, wf set' iit :i jj;Iuiici' the iiijirvclloiis dislriltiilioii (if
wliicli ill) inilividiiiil cell is ciipiililc. It isdoulttl'id it' Miiywiici'c
else in tlic :iiiiiiiMl kiiij^doiii a ^'rcatcr cxtciisioii or a niorc
iiiaiiil'old coiitad rclutioiiship is met willi in any cell. I'.acli
spinal ncnroiii' may l»c lliou<ilit of with the spinal ^an^'lion cell
as its centre, liavinj;' a I'aidike distriltnt ion (d' caidi process, the
peripheral fan collect in<j: impressions, I lie central fan eivin;; oil'
impnlses to the varions sensory end stations with \vlii(di the
lihrc, liy means oT its terminals and collaterals, comes into con-
dnclion relation. 'Tnc sum total ol" all the sensory end stations
in the spinal cord and mcdidla,as has been seen, includes prac
tically all re<^ions of the <:;ray nnitler.*
* 111 dill' si'iisc tin- sii-ciillt(l iiidttir areas of tlir ciini iirc iiImi in imil llu«
|ii'iiiiiiry I'lid still iiiii> of llic |ii'i'i|ili('nil ('('iili-i|ii'liil ('(iiiiiuclioii |iiillis. 'I'liu
ctTuils wliicli iiiivc foiisliiiillv lii'i'ii iiiiiilf le si'|i(iriilf ('('111 ri|n'liil fruiii ct'ii-
tiiliipil pallis liavc nearly always jjoiif too far. ('eiilri|ielal aiai < eiil riliipil
piiilis roriii pai'ls lit' units (if wliicli the ceiilripeltil path is one liiiil), wliile
liie (•iMitrifiif:;!il path is the nther. .Vs far as present kinnvleilp' warrants,
(his relation holds pxiii not only for the lowest ceiitres, Inil also, thoiif^h in
more eoiiiiilex form, (hroii^'hoiil Mie whole nervous system.
,1 ■■*;''
CIIAITKI} WW.
I'llltll'IIKltAI, Cl'.ltllllliAl, CKNTIMI'D'I'AI, N IOC IM»N I'.S COLl.KC 'Tl NO
ItOhlLY IMI'KKSSIONS.
'PIkisc iicrtiiiiiiiii^ lo llic iicrviis viij^iis iiiiil iicrviis f,'Iiissn|)liarvnp'us — TIidsc
pelt a ill in;; In I lie ncrviis vcslilniii 'I'lmsc iicrliiiniiii; In I lie tier v us iiilrr-
in<>iliiis — 'I'liosc pi'iliiiiiiiiLC 111 till' iiiTviis I ri;,'riMiiiiis.
2. Centripetal Neurones of the First Order (ooUooting Bodily ImpresBious) con-
neoted with the Rhombencephalon,
Till', pcripluTiil ('('111 i'i|M'tiil <ir sfiisorv iiciirdtn',-^ of llirrcrt'-
l)r!il Mi'i'vcs cdlltTt iiijf iiii|»r('H,si()iis fntm the licml iiiul iiccl< iiinl
rroiii some of I he iiilcniiil orjfjins, ufJircc in jjjfiu'i'al in their lorni
iiud rchition.'^ with wliiil liiis Ix' -n dcscriltcd ;is cliiii'MctcrisI ic u|'
Mic periplicral spiiiiil ccnlriin'lal nciifont's. 'I'lic cell bodies of
these cerehpid periphend .sensory nenrones :ife silnidcd in the
f^iuij,diii on the eerelii'id nerves. Theif pei'ipheral prohniffiit ions
puss to the snrfiiee of the liody and to the oi'j^faiis with winch
these nerves are eoiiiieeted, where they also exhiliit the various
mn'w v]\i\\u<xx {ciir/iii.scii/fi iicrrondii h'niiinnlid) mentioned lie-
fore. 'l"he eeiitral prolongations pass iido the hrain stem, and,
as von Ki'illiker showed, hifiireate, afterward ninniiii,' out into
thiMV terniiniils in the uray matter very mneli as do the dorsal
rootlihres on entrance into the cord. U e have here toi'onsidcr
the sen.sory portions of the nei'vns vaj,Mis, nervns ^lossopharvn-
j,'^eiis, nervns vestihidi, nervns iidei'inedins, and lu'rvus Iri^^emi-
nns. Ill their development the ccrehral peripheral sensory
neurones resemble closely the spinal sensory nenrones of the
first, order (lM^^ :)()T).
In order to make clear the relations of these nerves to their
nuclei (erminales in I he central nervons system, t here are intro-
duced here a lunnher of .sections taken at various levels from
two unbroken sets of serial sections (»f the brain stem (d' a new-
477
ii
47S
TIIK NKIIVOUS SYSTKM.
born bald' ( Fiffs. ;5()S-;5t>4). The central j)r(>lc)n<ifations of the
iini])olar f^anf^^lion cells of the tierriis ri/(/i(s (jj^anj^lion jufiulare
and ganglion nodosum), together with those of the ganglion
cells of the ttcrnis (//<i.s.s<i/)/i(n'i/ii(/eui< (ganglion superius and
ganglion petrosuni), enter the medulla oblongata mixed with
Baae of akxill
N. trifji'ittiituK..
Acusticd-fdcidlis
Auditory vesicle
iV. ylonsn-
phari/Hfieus
N. vai/tis.
N. accessorius. .-
Fifi. 307. — The (Icvc^lopiiifi <'<'i"<>l)ral nerves; head of a hiiniun embryo 10 mm.
h)iif;. ( After W. His, from Kollmaiin's text-hook. )
the motor fibres of these nerves, just making their exit, at the
dorso-lateral sidens (sulcus lateralis dorsalis). The sensory root
fibres of these nerves do not all enter at one spot in a compact
mass, but make a number of small biuidles which pass into the
central system at several points along the sulcus ( Figs. 35J() aiul
\VZ\). In the new-born child the linear extent of entrance meas-
ures about .0 cm. (Fig. WZ^t). The medullated fibres plunge
through the tractus spinalis nervi trigemini and the adjacent sub-
stantia gelatinosa, going obli(juely in the dorso-medial direction
j;
(IROUIMNfi AND CHAINING TOGETHER OP NEURONES. 479
toward the iiucUm of reception (nucleus ali« cinerea^ and nucleus
tractus solitarii) of these nerves near the floor of the fourth ven-
tricle. There is no bifurcation of the sensory fibres immediately
VUi. 308.- Transv .c section tliniiij;li medulla oblniiffata of newborn eliild at
level of (lecussitio leniniseormn. iSeries ii, section No. 5(1.) r.c, ciniiilis
centralis; IhcL, (li'cus.satio ieinniscoruni ; /•".«. i., tibrie arcuata' interna';
F.a.c, tiline arcuata' externa' ; /•'.(•., f.isciculiis I'uneatus Hurdaclii ; /■'.(■. to
F.r., bundles from fasciculus cuneatus to forniatio reticularis ; F.cls., fascic-
ulus cerebellosiiinalis or direct cerebellar tract; /•'.(/., fasciculus Kracilis
(Join ; F.r.jt., fasciculus ventralis ])roi)rius ; Xii.i-din., nucleus coiuinissuralis ;
S'li.f.f., nucleus funiculi cuneati et gracilis ; A'»./.(;.. nucleus funiculi gracilis ;
I'll-. I>.vraniis; T.n.ii.W, tractus spinalis N. trifjeniini ; N.;;.. substantia kcIh-
tinosii [Uolandi]. (WelKort-Pal preparation by Dr. .bdin llewetson.)
Nii.ac.
F.l.ttl
Nii.oQ.in
Nu.Q.
Fid. liOit. Transverse section of medulla oblongata of newborn child passing
(hroUHli (he lUK'leiisolivaris inl'erior. iSeries ii. .section No. 10;i. ) ('.)■., corpus
restiforme: l\ii.c.. libra' arcuata' interna' from the anterior half of the
nucleus I'uniculi cuneati : F.l.m.. fasciculus lonj;itudinalis medialis ; .V./.V..V.,
N. j;los.sopbar,vuK<'Us et vafius; \..\ll., N. h.vpojjlossus : \ii.ii.. nucleus
arciiatus; yit.n.r.. nucleus abe cinerea'; Xii.f.r., inu'leiis funiculi cutu-ali ;
\ii.t).ii.iii., nucleus olivaris accessorius medialis: A'imi./'.. nucleus olivaris
inferior: S'li.u.Xll.. nu 'leus N. b.vpofiiossi : /'//.. p.vramis ( uou-medullated) ;
N.r/.. substantia Kelaliuosa Kolandi : st.i.l,, stratum interolivare leninisci : T. n.,
tractus solitarius : 'r.s.)i.\'.. tractus spinalis N. triHcmini: I'.i^., ventriculus
(piartus. I Weisert-l'al preparation b.v Dr. .Iidin llewetson. )
after entrance, a fact wliich is not surprisinjif when the histoge-
netic relations discussed in Section IV are recalled. The bifurca-
,, I
t'
3 1
1!
;
■i i
4S0
TIIK NKItVors S VST MM.
1J(»M oi'ciirs just \vli('r(> one would ft /iriari r\\nH-\\\ to take pljuu',
iiaiucly, when [ho lilircs liavc rcacliftl (lie iici/j^liliorliood of tlieir
gray luicici of tiTiiiiiiatioii near tlu' lloorofllic ventricle. In real-
ity. lluMi, the analogy with the behavior of the dorsal root libres of
the spinal cord is nearer than if the hifureation occurred ininie-
itxii a<.i\
Num. Vtioim.
Flo. ;U0. — TninsviTsc section of nitMliillu ohlon^Mta jiiid crvclirllimi of nrwlioni
I'liiiil. (Scries ii, seelioii No. 1 l(i. i ('./•.. eor|Hls rcslil'oniic (llicpiiil iiumIiiI
hilcil corrcs|ioiiils in llie nniiii to llw dircrl cevclH'lliir trad): /■'./., Imndlc
Illicit iirii^,^|'iT|i«t.-« III till iiiiilll \ y ' 111^ iiiiii\ iiii>>«itiii _-..-.. _.-_, .,.
coiUiiiuous u illi the riiiiiiiiliis lateralis of the cord : l-'.l.iii., Casciciiliis loUKi
tiidiiialis iiieiiialis : .V./.V..V.. N. Klossopliarviificiis d vakils; .V,.\7/.. N. Iiypo-
^lossiis: \ii.il.. imcleiis <lciit:Ulls ; Sii.ii.r.<l.. iiiielciis N. coeiilcie dorsalis;
.\ii.ii.i\iii.. nucleus N. vesliliuli uicilialis : Xn.ii.n.il.. nucleus olivaiis iicccs-
sorius d(Usalis; S'li.ii.n.iii.. nucleus olivaris acc<ssorius niedialis; S'li.o.i.,
nucleus olivaris inl'eiicu'; Xit.t.s., nucleus tractus solilarii : /'.,('., pedunculus
ll<icculi ; /'//., pyiauiis; l'.il.ii.ri:-<l ., radix desceudens N. vestilmli: >7.i./.,
stratum inleidlivaic leuiiiisci : '.v;, plane of loUKitiulinal seelion No. (ili.
[NoTK. — 'this liyure has lieen disproporlionatel.v ii'duced in the reprodui -
tion.l I \Vei^;erl-l'al pi'epaiat ion li.v l>r. ,l<din llexvclsoii.
diiitely after eiitrjince. The hifiirciitioii of the tihres litis been
cari'fully studied by von Kidliker,* lleld,t tind Raiiion y Ctijal.]:
A(H'ording to von Krilliker, single fibres going to the iiiicleiis
* ()/>. cit.. nd. ii. S, ','40.
\ Held. II. I>ie JMidi^unuswiMst' der sensihleii Xerveii ini (n-liini, Ai'cli.
f. .\iiat. u. Physiol., .\iiiit. .Milh.. I-eipz. (I8!»0). S. ;t;i-:!!l.
J Uaiiiiui y Ciijid. S. ItcilrMi;' /ur Sludinni der Medulla Olilmiifata, etc.
Doiitsehe r(d)ersel/.. v. Hresler, Leipzig (,lM!l(i), ,S. 4:5.
(illOUlMNC. AND CIIAININU TOdHTllKK oF NKUUUNES. 4Sl
' :
r I- = s t S.-S r = J-b -
. >" • 3 v^' t; s s ■ z ■ "^
•^, I. s *-, z ■■ .^1. . . t .•~ •= —
C2C -; i.i IS'^ 2.> *•-; = i X
2i = r?-~^-|^.^'::^:.'i3-2
■ I: = •= r = ^ -r - = « ~ = ■-: 2
;:- 3"-.=,'^ s~- -J 7. = =- -
32
Uf
; i
1
1
. ,!„;•,. ,1!.
482
THK NKKVOUS SYSTEM.
k
>7 < ^ ^' fc. V w B
- ^ 13 d *^
= ;::[;§«
— .- -^ £3 n *->
■r ..s . £^^> a o
c . .
S X w
4. . ~-
^'"S.'
J=i -
y £ - . .
£ , r ..
c
c ^■^,=
2 rt — ic
"3 i; £ ■•"
.S 2 c ^
:i ...2.J .,.,
— ■/: ^ •— X
= .,■ :- C
S • ^'^ t^ - —
. « ^ a S 3
u
^■1^'r.>-. .It.
15-'. .. rt ? =
^ = *: =
= ^ X "
2 =
5. r
li
c ciS K'Z K.~ o
OROUPINd AND CIIAININU TOUF/rilEU OK NELRUNKS. 483
^ 7. p i
est;
5t 5: 'E.'-
= -rs a'- t:.:i 5 i-=-^ -
< = c 3 3 i := b r g; . §i
'5 ' . . ~. •- — 3 .H K ''' ^ -S
B •• „ = = y. i E"- i O
\
1'
1. t
:*
;•<((;>• •■<>]
iklll
484
TllK NKinOl'S SYSTKM.
!il;»' cincrca' dixiilc in tlic Itimdlcs nciir tliis init'lciis, tlic rest of
I he lilircs inside it. 'Vhv lihrcs i-nicrinj; I he Iraclus soiilarius
undergo division, l)ut not all at tliu sanu' level.
Vw. :n 1. TrMiisviMso st'ction tlirDU^Ii islliiniis rhoinlicixM'iihali ol' iicwlxini
Uiilir. \V('i};rii-l';il, scries ii, Mclioii Nn. '^'liS, ) /I'c.coi, , liriirliinin ruii-
.imicliviim ; ''.('.. rolliciilus iiilcrinr ; y, iiinli'Us (U'sciiliiil l).v Wcsliiliiil as
luiilialily ciinrctiird ill I lie iiiiniii iil' ilic N. t iiiclili'iirls : /'./.mi., rasficiilus
loimiluiliiialis iiicilialis; /•'./'//., rasciiii I i li)iiyituiliiialt's [iiyiaiiiidalt'sl : /../.,
IciiiiiiMiis lalinilis : l..m., Iciiitiiscus mcilialis; .V. / 1'., ilrciissilio iH'rvuriiiii
Iviiililcariiiiii ; .V. I'., N. Iri^'i'iiiiiiiis; Sii.l.l.. iiiirlciis Icniiiisci lateralis;
.V". /■./.. iiiu-leiis relieiiljivis leuiiieiili pniilis ; It'.il. 1".. radix deseeiidens [iiiesell-
eeplialiia] iietvi tiiueiiiiiii. I'l't'iiaraticni liy Dr. .Iiiliii llewelson. ^
The tignre copied from Held (l"'iir. 'VH<) shows root fibres
dividing, ont' branch passing to the nucleus ahv ciiuM'ea', the
other descending in the tractus solitarins. These descending
fibres give otT collaterals (I"'ig. :{t?T) and torniinals, to end in the
adjacent gray matter (nucleus tractus solitarii). Kainun y
("ajal denies the existence of typical bifurcations (at least for
the majority of i . fibn^s of X. 1 .\ and N. X), and thinks that
* Wost pluil, 0. Ueber ciiicn Fall von ohroiiisolier iirofjrossiver Jjiilimiiiii,'
d(>r .ViiireniiiuskelinOplitlialniojilej^ia externa) iielist l?eselinMlimiji von (ian-
glieM/elloniinippen im Ho 'ho iles Oeiiloiiiotoriuskenis. Arch. f. I'syi'liiat.
un.l Nerveiikr., Herl.. H.l. xviii (18H7), S. yW.
»
»U.,
(il{(»ri'IN(l AND CIIAIMNd TOOKTII KU OK NKIMIONKS. 4^5
t licsc (ihrcs, tlisolx'viiif; t lie ^fciicnil law ol' diclidt oiiiy, iirf <l('V(»i<I
of asft'iidiii;^ liiiilis, ill! tlic librcs t iiniiii;^ down in t.lu' Inictiis
soliliirius. Tlic liltrcH ciitcriii;; tlio nucleus tilu' cincren', whicli
ill tlic iiiouHc is colli iiiuoiiH with tho iiticlcus trtictiiH Holiliirii,
lie looks upon as collaterals. Tlie <,fcncral course of llie tractiis
soliiariiis is lies! studied in liori/ontal sections of the iiahy's
iiie(liilla slained hy tint Weif^crt-I'al method ( l''ij.r- -{'vH). in its
St.(]r,c,-
R.d.n.V:
Nu.Ci
Nu.cs(i
kcMw-
Fid. :jir». — 'Priiiisvi'i'sc st'clioii thniiiKli lirtiin of iicwliorii Imlir. Level Dfedljii'iili
inCericpres III' corpdni (|ii;i(lrii;eiiiiiiii. i \Vei;,'eii-l'iil. t-eiies ii. seelimi No. 2iMl. i
III. II r., Mi{iie(lii('l IIS ('('I'cliri : >i. lilni's iiiiiiiini; IVdiii hileiMl leiiinisriis lowiird
<l<ii'sil liiinli'i' ril' Imieliiiiiii eiiiijiiiii'liviiiii : llr. ( 'mij.. Imieliiinii eciiijiinct iviiin ;
<'.(■./'., eiiiiiiiiixsiMi' IhIwccii (lie iiilliciili iiileriiircs ; /'(C./icc//.. vciil liil |iipiii(in
of lirilelijiiiii cciiijiliieliviliii, wliieli ill riMJily I'urnis :i eoiiiiiiissin'e liel ween (lie
>li|iei'iiir iiiiilei III" I lie vesi ilniliir nerves nl' tlie (wii sides ; /•'././».. riiscienlils lon-
jiiliiclin;ilis inediiilis : /•'. /'//.. riiseicnli liiiit;iln(liiiiiles pniilis i iiyniniidiilesi ; I,. I..
leinnisens lnler:ilis in Imi'^i' |i:irt leiiniiKililiK in llie niieleiis i>l' (lie eollirnlns
inl'erinr; /,.«/.. leinnisens iiiediiilis: .V./l.. \. I nielileiiris ; .V//.r((//.n//',. nneleiis
<ii||iciili iiil'erioris ; Xii.r.s.il ', nncleiis eenlnilis sillperinr, |iiiis lalenilis;
\ II. C.S.I m ), n Helens cell I nil is sil|ieii(ir, |(iiis ineilinlis ; H.il.ii. I'., liidix desi(iiden>;
rineseiiee|ili;iliiii] N, lriy;eniini ; S/.m-.r.. slriilnni i-riseiini c ciil rule. ' I'repiini-
liini li.V l>l'. .lolili llewetsnli. i
])assa{;e spinalwanl it i,fradiially approacdies the median liti", lyiuj^
in its lower part medial to the nucleus funiculi gracilis. Its fibres
f
m
; I
i
1?
J
/ 'i
t'
'!!!■!
48«;
TIIK NKKVOUS SYSTEM.
'' 1
%
\^
f
can he seen tcM'iuiimtiii^j iit tlilTcroiit li'vcls in the nuck'iis tractus
solitarii wliicli lUM'oinpimic.s it. The f?niy mutter of this mielejis
iiion^ or IcHH .surrounds the tract, l)ein<? better (leveh)|)etl in sonic
jihiccs than in others. At the cephalic extremity of the tract us
solitarius a mass of ^ray matter can l)e seen passing' heatlwanl for
11 (listaneo of I or •.* mm. ( Xn.fr.sn/.^ Fi},'. W'-iH). From the <,'enerul
appearance of this mass, and the character of the cells within it,
St.gr.c.
St. alb. p.
N.iy.
4'_)_IJu.l,s.
Elm,
L.tn.
DpcBr.Coni
5.n. ^
l''l(i. lUti. 'I'riinsvcrsf sccliipii llin)ii;;li iiusciici'plialoii nf iic\vl>c(ni IkiIm'. I.cvcI
1)1' ccilliciili suiMTiiins III' (oriMiiii (|iiii(liif;(iiiiiiii. ( WciKcit-I'iil, .'^(^i(•^^ ii. sec-
lion .Nil. H15S. ) . I(/. (■(■)•., ii(|ii(<liiiliis (•(■icliri : /'cc. /)C.ro/i;., (Icciissatin hiiuliii
iDiijuiiclivi ; />./.. (Ictiissiitiii Icnincnti vintiali.s {rcKlrnli' llitiihn(hii-irjiiiiii oi
l'"ipiil ) ; F.I. III.. I'iisiiculiis l(tii;;itii(liiiiilis iiicdiiilis ; /•'. /'//., fasciculi |>.vi'aiiiiilalcs
ill the pars l)asilaiis pimlis : /,./«.. Iiniiiisciis iiicdialis ; .V. /I'., N. tniclilcaris ;
S11.I..1.. nucleus lateralis supi^rior ipf I'^leclisi^' ; Sii.ii.lV.. nucleus N. tnicli-
lcaris; Sl.iilh.ji., stratiiiii alliiiiii pi<p|'iiiiiliiiii : Sl.ijr.c., stratmn Kriseiini ceii-
trale; S.ii., sulislaiitia iiiyra. ^ I'reparaticpu liy Dr. .Inliii llewetscpii.
it is probably to be rej^tirded tis tin u[)\vard continutition of the nu-
cleus tnu'tus solitarii. The niaintemuice of the f(eneral calibre
of the tractus solitarius as it pa.sses s])inal\vai'd renders probti-
ble tlie view that tlie majority of the stem fil)res pass for a long
distiince s])inahvard, cliieHy collaterals bein<r iriven olT in the
course of the trtict. In sections of the btiby's medulla, tit the
spinal end of the trtictus .solitarius, there is to l)e made out on
each side of the middle line a distinct mass of cells, evidently
(}U()UI'IN(J AM) CHAINING T()(iKTIIKll OK NKlUdNKS. 4,^7
<'()im»'('t('«l witli the triictus .solitarius (.\ii.i(nii., Fig. 'MW). It ia
not iiiipossililc that tliis corrcspoiids to tlu' i/tnif/liiiti (■otiniii.'itiU'
r((l(\ wliiili liiis l)i'('ii (Icscribod by liiinion y Ciijiil in the inc-
(liilhi ol' the mouse. According to him, in the mouHu this nu-
cleus forms an oval mass of cells, \vhi(di extends hridgidike just
dorsal to the central canal (between the ependynial cells and
the gray c»mimissure of tiie cervical cord). In it termiinite u
large number of the fibres (a(!eording to Kanion y Cajal, no
less than three fourths of them) of the tractus solitarius of
the opposite side, so that we have to do here with a true termi-
nal ilvrnxsuHo trdctuK solilurii. The fibrils branch manifoldly,
and are so numerous tiiat the plexus fornu'd by them is one of
the most complicated met with inside the central nervous sys-
tem (Fig. '.Vi\)).
alb. p.
Fi<i. 317. — Ti-iinsvcrsc section tlirousli nicsciK'ciiliiiloii, colliciili siipcridrcs of cor-
poni (iUii(lrif;i'iiiiiia ;iii(l (•crcliral iH'diiiiclc ol' ncwlinin IkiIpc. i WciKfit-l'al.
scries ii. section No. :5SI.) A<i.ci'i.. a(|nc(luctiis cercliri : ('nil. sup.. I'ollieniiis
siiperioi' ; />.^, decnssatio tef,'nicnli dorsalis 1 finifiiiiiinrtiiir Iliiiilinilirir.111111 i>(
Meynen): I\l.m.. liiscicnlus lon}jitii<linalis incdialis: /•'./'//.. Cascicnii pyra-
niidales in tlie iiasis iicdniiciili ; /•'.c.i .1/ ). I'ascicnlns retiodexus Meyncrli :
I,.)ii.. lemniscus niedialis: .V». /•'./.»/., nucleus fasciculi loUKitudinalis niedi-
alisor nucleus cuniniissura' posterioris 'iilirri'i- Ondiiiiiiiliirin.ih'fni of Darksclie-
witscln: .\ii.ii.lll, inicleiis N. oculoniolorii ; .\ii.r.. nucleus rulier; A'.///.
N. ociiloniolorius : St.nlh.i).. stratum allium |)roruudiMn : .^l./ji-.c.. stratum
>;i"isi'Um cenlrale: .s'.»., substantia ni^ra ; a, rej;ion of Kleclisiji's Fii.s.sschleife ;
P. temporo-occipital tivu't to pons; 7, frontal tract from ))allium to i)ons.
I Preparation liy Di'. John llewetsou. 1
Outside the central nervous system the nervus vagus forms
numerous anastomoses with the sympathetic. The relations
are well shown in Fig. 330.
il
488
TIIH NHItVorS SYSTK.M.
Str.alb.pi
iiij;, sciU's 111, sec
liitcnilis toward •
0. (Icciissttin
(■(plliciiliis '•
/•'.(■.. fiisci
Fui IMS. Ilitri/iiiital scclinn tliniii;;li tlic iliDiiilpi'iiccplialdii and iiicscncciilialdit
ola iu\vl>c>ni halic. ' vcl of imclciis iicrvi alHliiccntis. ' \V<'i^'ci't-ral slain-
ti(t. I o, liltrcs riiiiiiinv' tVoiii region of linmiMiis
I'acliimii conjiiiictiviiiii ; .(</.(•.. a(|iu(iiittiis ct rcliri ;
root cd' N. trittciiiiiiiis ; r..v.. colliciilus siipcrioi' : Ci..
..())(/.. l)nicliiiiiii cciiijiiiicliviiiii ; f'.c., corpus nslitnrinc ;
atils: /•'.;/.. fasiiriiliis jtr.icilis : I.. I.. Icninisciis lateralis:
.V./r.. N. iris: .Vk.k.c. iiiiclciis alu- ciiifnn' : .V»..^.<'.. iiik-Uiis limiciili
ciincati : .\>... ./•. iiinlcus fiiiiiciili gracilis: Xii.ii.cil.. imclciis N. coclilca' dor-
salis ; .\ii.n. 17., nucleus N. alidilceiilis : Xii.ii.i'.l.. miclciis N. vestilmli lateralis
I Deilers i)ars media I is ; Sn.ii.r.l.,. nucleus N. vestilmli lateralis Deiteis pars
lateralis: Sii.ii.r.in.. iiucleus N. vestilmli iiie<lialis i .'scliwallie ) ; .V/i./i.r..". nu-
cleus N. vestilmli supi'i'ior von lieclilerew ' : Sii.ii.XI I., nucleus N, li.vpo-
filossi : .V». )'., autero-lateral e.xtreiiiilv id' nucleus N. vestilmli meilialis;
li.il.ii.t.. radix descendens [iiieseiiceplialica] nervi triueniiui : l,'.il.)i.rfsl., radix
desceiideiis N. vestilmli: >y/-.((/^(./).. si laliiin allium proluiidum : 7'c..v,. tract us
solitarius : I'.i/.. ventriciiliis (luartiis. I'repanitinii liy Dr. .lolin ihwetson,)
«K<»ri'IN(J AND CIIAININCJ TOOKTIIKH (»K NKl'UoXKS. 4,sj>
CoU sup.
/l<^.f♦l■.
St.alb.p.
■ H,. V .i N.W
^- ■• ^ -DecBecht.,
Nucl.n.abd.
Rad.dPsenvRSt
Fasclmed.
Corp. rest.
.j)^Nu.n cochLd.
■Tr.sol.
■Nuclf.cun,
Nucl.n.hijp.
-Fa cun.
■NuclUr
■Ya.Pt.
Fl(i. 310. Iforizontal soctioii fliniiij.'li tlic rliciiiiliciiccplialnn mid mcscncciiliiilriit
tit'a iH'wlHini lialic. WciKcrt-l'iil staiiiiiifi. Level ol' ventral jiart of iiiieleiis
iiervi atiiliicciilis. i Series iii. .■^ei'ticiii No. 7^. i .l(/.(cc.. a((ue(lii<'tiis eereliii;
Hi-Kili.Ciiiij.. liiacliiiiiii coiijuiutiviiiii : (hlLsiij).. collieiiliis siipericir: < 'oil. inf.,
folliciiliis inferior; ro/'y/.ro^.. corpus restit'ornie ; l>ii. Itiilil.. tilires of ventral
jiortioii of liraeliiiim con.jiinetiviiin forinitif; a connnissure between the supe-
rior nuclei of termination of tlie vestibular nerves of tlie twositles; I'li.nin.,
fasciculus cnneatus: /■'(». i/c. fasciculus Knicilis: F.<(.j.( IV.vM, libra' arcuatic
pertainiuf; to llie ciiitnil vestibular pailis: luisv.l.iniiL. fasciculus lonjji-
tudinalis nudialis: l.fiiiii.ldt.. b'niniscus lateralis; Mnl.nlil., medulla ob-
longata; .Vc.scHc, meseu4'eplial<ui ; S.triirhl., N. t rocdilearis : y.Widi'i: .
<lecussiitin}; portion of the root of the N. trifjeminus ; .V. 17//., nulix N.
facialis, pars secunda : S'lirl.f.ciiti.. nucleus funiculi cuneati: Xiicl.f.iir..
nucleus funiculi gracilis; .\iicl.)i.iili(l.. un<lcus N. abducentis: yit.ii.riiilil.il..
nucleus N. cochlea' dorsilis: S'Krl.ii.ln/ii.. nucleus N. hypo^dossi ; yii.lr..iol..
nucleus tractus solitarii : Hiiil.ilisc.n.nsl.. r.idix descendeus N. vestibuli:
St.iilh.i)., sti-atuui album profnnduui: Sl.iir.c. stratum K'''f*<'""' ccutraloi
Tr.siil., tractus siilitarius. i Preparation by i)r. .lohn llowct.soii. i
'
it
!- ■
: {
■■!;
I
"I
w
490
THE NEKVOUS SYSTEM.
3
I'
H
U
St.9.c.
-Nu.J s.
£
o
Fid. :wo.
I'll
m
' m
I
Vui. ;ttO.--lI()riz(iiital scctiim tliroiiKli the ilioinlu'iict'iiliiiloii iiikI iiicsciitcplmliiii
of tlic ticwboni lialx'. Wcififrt-Pal staiiiiiif;. Level of tlie rasciculus l(iiij;i-
tudiiialis medialis. (Si^ries iii, se<'tiiin No, 80. ) .!(/. <rr., a(Hie(luctiis eerelui ;
Itr.cinij.. linicliimii coiijiinetiviim ; ('.Ili'cht., (•luimiissure Ix'tweeii Mecliterew's
iiiielei of tlw two sides; ('i>ll,.i,, (•ollieiiliis siiix'rior; f '.»•.. corims i'estit'i)niie ;
F.ii.i.. libra' arciiata' inteniii' ; F.rlx., t'asciciiliis cerelu'lliispiiialis or diri^ct
cereiicUar tract: Ren., laseiculus <aiiieatiis: /■'.(^, t'aseiciiliis unu'ilis: F.l.m.,
fasciculus louKitudiualis medialis; /,./., leuiuiseus lateralis; /...v., leuiuiscus
superior; .V./T, X. troclilearis ; .V..W()^^, N. trifjeuiiuus, i)ars uiotorius :
A', r, N. trigeminus; .V.I7, railix N. aliduceutis; A. l7/((i), radix N. Iiuialis,
l)ars prima; .Y.I7/i('). radix N. facialis, j)ars secuuda; X.n-st.. \. vestil>uli :
A'. /.V, .V, radices Xn. {{lossopliaryiifjei et vani ; .V(( ../'.(•»., nucleus funiculi
cuneali ; A'»../".f;.. nucleus funiculi firacilis: jV».».c.'/., nucleus X. coelilea-
doi-sjilis ; A'».». r., luu'leus \. trij;emini ; .V».)i..V//, nucleus X. liypofilossi ;
yii.l.i., nucleus lateralis sujicrior of Fleclisij;; L'.d.ii.irsl., radix descendens
N. vestilaili ; Sl.ij.r., stratum };riseum eeuti-ale; Siih,iicl.lii)l(iii<'i, substantia
Kelatiuosa Rolandi ; Tr.snl.. tractus solitarius; T.n.n.l', tnictus spinalis X.
trifjeniiui. (Preparation by Dr. John llewetson.)
"' ~ ' * ' ■
.. t!
■1 ■ C!
Fkj. .'521. — Ilori/oiitiil section timing')) tlio iiicdiilla, pons, and nii(l)>i-ain of a now-
horn lial)c. \Vcif;crl-I'al stainitiiL;. Lvvv\ of nucleus nervi oeuloinolorii and
nucleus nervi lioclilearis. i Series iii. section No. 10(1. i .I7. co'.. a(|Uedlu-tlls
cen'hri : /(c. co/i.;.. l)raeliiuni conjiinclivuni ; r./)., eoniniissura posterior cere-
lui ; ('. liiclil.. eoniniissure l>et\veen i?eclitere\v"s nuclei of the two sides; r.;-.,
corpus restifornie : l-'.l.ni.. tasciculus lonKitudiualis niedial's : /'.c. In I'.r.. lihr< s
from fasciculus cnneMt us to forniatio reticularis: Fih. d-i: nil.. iWiv.v arcualic
interna': /•'. c//.. fasc. cuneatus ; /•'.)■.((.. forniatio reticnlarisalha ; Mat. ('..radix
niotorius N. trif;<'niini : .V. 17.. radix N. ahducentis : .V. res/,, radix N. vestih-
nli : .V. l7/.i('. '. radix N. facialis, pars seen nda : .\. I.\ miil X. radices Nn.
Mlossopharvnirei et va^i : X.XII. radix N. h.vpojilossi : Xii.c.s.> tn >. nucleus
centralis superior, pars niedialis: Xii.v.kjI >, nucleus cent I'alis superior, pars
lateralis : Xii.l.l.. nucleus leninisci lateralis : Xii.l.s.. nucW'Us lateralis superior ;
Xii.ii.lll.. nucleus N. oculoinotorii : Xii.ii.H'.. nucleus N. trmhlearis: /...v.,
lemniscus superior; Xii.f.ii.. nucleus funiculi ;;raeilis; Xii.ii.r.i-.. nucleus N.
cochlea' vent rails : .V».».17/, nucleus X. facialis: S.;/.. snhstantia jrelatiuosa ;
Sl.i.l., stratum intemlivare leninisci; Sm.]'., radix sensiu'ius N. trijremiui ;
St.il.i:. siratiini uriselini centrale; Suh. iirl., slihslantia ^elatinosa near eii-
traiice of seiisor.v part of N. trigeminus: 'I'r.s.n.l.. tiaetus spinalis N. trijjem-
ini : 'I'r.fr.iix.ll., ti'act from Deiters' nucleus to the spinal cord. 1 {'reparation
h,V Dr. .lohn Ilewetson. 1
•GUUl'
•I.ING AND CHAINING TOGETllKU OF Ni:CRONKS. 4<.»1
C.p.
-Aq.cer.
Fv.. MX.
m
I 1
i
■-«
rM
41>2
TIIK NHItV(»l'S SYSTEM,
^"^■'•^c-ft
o Nu.r.t. \ s, m I f l:4-^>v-^ J'-^;,
)/Vt:^^:m :;m A*. /■'";
.,■: , ,. y.^|^->^
Sen.Y,
H.Y1I
N.Yest.
•H.YI.
IsM
IctcEr.
Fig. 3^2. IIori/.oiit;il scctioii tlimuKli the incdulln. ixins. and mi(ll)riiin iif a ncw-
lioni l)alic. Wcifji'rt-I'al staiiiiiifj. Level dC tleeussiUio liracliii enii.jimctivi
ami of nucleus reticularis teffuieuti. (Series iii, seetion N'd. lOH. ) ('.p.,
eiiinniissura posterior eerehri ; Dfc.H.r., decussitio liraeliii eonjunetivi :
Pir.Hrrht, eonnnissure lietweeu l{<'elitere\v's nuclei ; II. t., tilires to decussjilio
tefinu'nti ; F.ti.i.' (\
Whnv arcuata' interna' from the nucleus funiculi
ciineati :
/'.
fasciculus cuneatus; F.v. to F.r.. bundle from fasciculus
euneatus to forinatio reticularis; F.tj., fasciculus ni'Jieilis; F.l.m., fasciculus
loUKiludinalis medialis : /,.
lemniscus medialis : /,./.. lemniscus lateralis
Milt. v.. nidix motorius \. triKemini ; X.VII., radix N. facialis. i)ai>i secunda :
\.n'iit., radix N. vestiliuli ; .V. 17., nidix N. al)ducentis; S.XIl., radix N.
liyi)o(;los,si ; .V. .VA,, radix X.
. II l.id). nucleus X. ocidoniotorii,
pal's lateralis: .Vi/.ii. ///.'/> ), nucleus X'. oculomotorii, ]iarsimi)ar: yn.c.-t.ih
nucleus centnilis superior, pars latei-.ilis: .Vk.c.v.
micleiis centnilis
superior. i)ars medialis : Sii.l.l., nucleus lemnisci lateralis; Nit.u. VII., nucleus
X. facialis: Xn.y.c.r., nu<'leus X. cochlea- venlnilis: Sii.r.'i.. nucleus ceii-
tr.ilis inferior ; Sn.r.t., nuc-leus reticularis teKineiiti ; .V»./..s'.. nucleus later.ilis
superior: St.qr.r., stratum firiseum centrale; Sfii.]'., sens(u\v root of X.
trifieminus: N.;;., suhstantia Kelatinosii Kolandi : Tr.fr. iiii. I)., tract froin
Pciters' nucle\is to the; spinal cord: T..s.ii.l'., tnictus spinalis N. trif{eniini.
( Preparation hy Dr. John Hewetson. -
GKori'lNCJ AXI) CilAININa TOGETlJEll OF NKUHONKS. 403,
Fasc.retrof.
494
THE ISEKVOUS SYSTEM.
,Ku.n, nr .
Nu. ruber.
L.m.
a. Yin. Uoct^i
H,YI
■Fl,
•Fa.iADacl)
Fro. :W4.
Fid. 324. — Horinontal section tliroii);)) the inodtilla, pons, and niiill>niiii of new
born I)alu'. Ijcvcl ot'stnitinn iutcrolivarc Icnmisci, corpus trapc/.oiilt'inn and
niulciis nilnT. NVciKcrt-l'al staining, i Scries iii, section No. lUti. i r./., cor-
I)us tnipezoideiini ; Dec. llr.Ciiiij.. dcciis.siitio linicliii coii.jiinctivi ; />./., decus-
.satio tcffnicnti ventr.ilis (ventral tegmental dccnssiition ofKorel i; F.ii.i.i Dec.l.),
tilira' arcuata' interna' (decussatio leniniscoriini) ; /•'./., tilires continiionswitli
the fnnicnliis later.iiis of tiie spinal cord; F.l.m., I'asciculiis lon^itudinalis
nieilialis; /•'.;•., I/.. I'asciculns retrodexns Meyiierti ; l..iii., lemniscus nicdialis;
y.lll.. radix N. oculotnotorii ; S.Mol.l'.. motor root of N. trigeminus;
A'.Scii. r.. sensory root of N. trigeminus; .Y. 17//. (coc/i. i. nidi.x X. cochlea' ;
.V. 17//. I rest, I, radix X. ve.stihuli ; .V. 17., nidix X. ahducentis ; A'. 17/., radix
X. facialis, pars s<'ciin(hi ; .V. A'//., radix X. hypo>;lossi ; Sii.J'.l.m.. nucleus
fasciculi lonjiitudinalis medialis. or nucleus commis.4ura' pctsterioris {olierer
Oniliimotiiriit.iLmi of Darksehewit.sch ) ; A'». ».///., nucleus X. ocuhmiotorii ;
Xn.ti.it.m.. nucleus olivaris accessorius medialis; \ii.i>.i., nucleus olivaris in-
ferior; \ii.i>..i., nucleus olivaris superior; .Vd.cKftc;-, nucl"Us rul)er; N7.(.).,
stratum interolivare lemuisci ; .S.«., suhstiiutia nigra, i Preparation t)y I)r
John llewetsou. >
88
rstt't:
Fl(i. :wr). — hiiinriini ]ir<'|(ari'(l ))y Miss !•'. Siibiii t'lcnii a sciifs of s(<'tii)iis tliriiii(;h
till' Imiiu III' a iifw-liiini lialir. shiiwiiiK the nuclei uf the ((rclnal mrves ami
tlir area iil' exit ami iil' ciitraiii'i' of tlic runts nf llii' ri rclinil m rvis in Hat pru-
ji'itiiin. ((. line nl'lali ral fdifc id' fiiiiilli vent rirlc ; il. il. it, il. fitsca inrcrinr;
c. I'liVfa snpcriiir; ;;, lateral surl'ai'i' nl' rlinnilicncciilialun ; ///.. area nCixit of
N. iicnloiuiitorius : /!'., area of exit of N. Iroclilraiis ; I'., area of exit anil en-
IraiiiiofN. triKi'ininiis ; 17., area of exit of N. alxluccns: 17/.. area of exit of
.N. farialis; 17//. {ciii'li. i, area of cntnincr of N. coclileii' ; 17//. < rrslih.'i, area
of I'Titrancc of \. vcslilmli: /.V. ami A'., area of intrancc of N. ^lossopliaryn-
t'eiis et vajius; .\7., area of exit of N. ai eessovilis : .V//., area of exit of N.
hypoKlossiis; .Vi(. ».///.. nuileiis X. oculo-niotorii : .Vi/.n./l'., nuilens N. troili-
learis; Xii.ii. I'.i »(./(. ), nneleus niotorins jirineeps N. trineinini : Xii.ii. 17., nu-
elens X. aliilneentis ; Xii.ii. \'II.. nucleus X. facialis ; Xn.ii.. niiclens aniliinuus :
.\ii.ii.r.. nucleus ahecinercie : .\ii.ii.r.m., nucleus X. vest iliuli nicilia lis ; Xii.ii.r..t.,
nucleus .\. vest iliuli superior; .\'ii.ii.r.l., nucleus X. vestiliuli lateralis i Ueiters':
,V((. «.(•.</., nucleus X. cochlea' ilorsalis ; Xii.ii. r.r., nucleus .X. coclilcie vent ral is :
Xii.ii..\ll., nucleus X. liypoKlnssi ; H.il.ii.t.. railix descendens inesenceplialica
X. tri}{eniini ; L'.il.ii.r.. railix ile.scenilens X. veslihuli: >'.f/.. sulistantia jjelali-
no.sa ; 7'. sdI., tractus solitarius ; Tr.s.ii.t.. tractns spinalis X. triKi'inini: I'l'nl..
ventral horn cells. The numbers to the left of the (irawinjr inilicate approxi-
niately tile levels of l!ie cnrri'.siHtiidinjr transversii sections represented hy
Kif{s. :{US to 317.
The plane of the sections from whicli this diagram was made is not (luite trans-
verse hut somewhat ohlinne: the dor.sal surface of the medulla lias lieen
struck hy the knife more cereliral ward than the ventral surface, the anyle
formed hy the plane of the section with the longitudinal axis hein;; ajiproxi-
inately seventy decrees, as measured on the cerebral side. This accounts for
the evident ' slight i displacement cerebralward of the structures in tlie ven-
tral imrtions of the sections as compared with those in the dorsal iiortions.
.
(iUUUriiNG A.ND LJlAlMiNG TOUETllEK OF NEUKONES. 4<j;-»
liiii
!ti|>
I !
'1!
\
I
-^
;ii
4<J0
'I'lIK NK|{ vol's SVSTKM.
.V
i.
m-14.
Klii, :!:,'(>. I'.ndiiiHs III' axiiiu's dl' N, vii«iisiiii(l
N. jilossoiiliiir.vimciis, 'I'lic liliics tiiniiim
iliiwii iiilii tlir liiicliis Milit;iriiis arc well
lowii. (Al'liT II. Ililil. Anil, r. Aiiat. ii.
riivsiol.. Anal. Al.lh., I,<'i|i/... isit;.', 'I'Mf. i,
l'i«. I.)
Fill. !?^'7. — Tiactus siilitiiriiis lit' a six-ilay-iild cat. nt'licalc cultali'ials arc seen
I'omini; tVniii llic main axntics. i After II. Held, .Vrcli. t'. Aiiat. ii. riiysinl.,
.\iiat. .Vlitli.. I.iiii/.. !*<!••,', Tal'. i. I'ij;. -i.)
I
|:ii
(iliOll'INO AM) CIIAININM; 'nxiKTIIKIt OK NKntoNKS. 41)7
Coll sup.
Stalb.p.
ColUnf.
Stgrc.
■Brach.Conj.
YCdec.)
m
DecBecht.,
Nuci.n.uDd.
Rad.dpspnvpjt
Fasc.l med.
Corp rest.
U.n cochl.d.
Fui. 'i)iH. Ilori/diit.'il sci'tioii tliriiiiKli lln' rli(iiiil)i'iii'('|ili:iliiii niid iiicsiiicciilialiin
(it'll iicwliiini liiilic. WciKi'i't-l'al sti(iiiiti«. Level ol' vi'iitrul purl of nucleus
iierv i aliillleenlis iSeries iii, sectinii No. 7^. 1 .((/.cci-., luiueduel us cereliri ;
llnii'li.Ciiiij.. luaeliiuni eoiijuuctivuin : ('iill.siiii., eiillieulus superiiir : ('till. inf..
(•(illieuliis iuferiiir ; ( '(irii.nsl., corpus restirornie ; Ihr. lUihl.. (ilires of veiit ral
jtortion of luacliiutu cou.jutu'tivuiii t'orniiiiK a couiiuissure lielweeu tlie supe-
rior nuclei of teruiinati(Ui of the vestiliular nerves of tlie twosides; lui.iiiii..
fasciculus cuneatus; I'ti.ijr.. fasciculus gracilis: /•'.((.(.( ^c.v^ ), tiline areuatie
pertaining to the centnil vestihiilar paths; lui.if.l.iiiril., fasciculus lonyi-
tuilinalis niedialis; l.nmi.liil.. lemniscus lateralis; Mrd.iihl., medulla oli-
louKala : iUcwi/c, inesenciphalon : X.lnirhl., N. Irochlearis: iS.l'.'iln: 1.
dccussitiuK portion of the mot of the N. trigeminus; .V. 17//., radix N.
facialis, pars secunda ; Snrl.f.citii., nucleus funiculi cuneati ; .\iii-l.f.(ir.,
nucleus funiculi unuilis: XiiiI.ii.iiIkI., nucleus N. ahducentis ; .S'li.ii.rothl.tl.,
inicleus N. cochlea- dorsulis; .V»c/.i/./i ///).. inndeus N. hyponlossi ; .\ii.lr.si)l.,
luicleus Iractus scdilarii : Hiid.ilf.sc.n.risl., nidix descendeus N. vestihuli;
N/. ((//). y*., str.ilum allium pnd'undum ; .s7.(/;-.c.. stratum K'iseuiu centrale:
Tr.Hul., tnictus stditiirius. 1 Preparation liy br. John llewetsolij
ii
■r»/i
498
TUE NEI4V0US SYSTEM.
Fio. :Wi>. — ( 'ross .scctiidi tliniUKli tlic rhiiinhfiicipluilnii i)f a four-diiy-olil tni>iis<>.
lAI'tcrS. Uainoii y ('ajal, licitrun /.mn Stiiilimii dcr Medulla Oliloiifiata, etc.,
Lfii)/,., 18i(t), S. 48, Kifj. lU.) I, iiiiclciis N. Iiypo^lossi ; /;, miclcus ciiin-
inissiiralis ; <', iiiiclciis olivaris inferior ; />, tiactus s])iiiali.s N. triKciniiii ; /■',
motor n»)t of N. vafjiis and N. KlossopharynKciis ; F, iniclciis anibiKim.s ; (1.
posterior extremity of nucleus N. vestiliuli nidicis descendentis ; //, eross
section of tra('tus solitiirius ; /,. lil)res h'UUK to inndeus olivaris inferior; «,
pyramis; h, collat<'riils from tlie pynimid and from the substantia allia lateral
from it; d. collaterals from tlie fasciculus later.ilis proitrius ; c, sensory col-
laterals for the nucleus aml)i}ruus ; /, n^i'urreni liltres in motor roots which
run toward tractns spinalis N. triRemini ; ./, crossed motor root lihres of N.
va^usand N. Kl<»<i^"I>haryunens ; h. collatenils of th(> sensory root of the N.
vaKUs and \. glossoijIiaryuKeus runuiiiK in the fasciculus solitiirius ; i, proto-
plitsniic commissure hetween the nuch^i N. hyiioglossi of the two sides.
t'l
tiK()LI'IN(i AND ClIAiNlNCi TOUKTllEU OK NKL'UONKS. 4Jj<j
The cell Ixttlics of the ju'riplicnil iicunmcs corn'spoiuliti;,' to
tin' nrrnis nslihiili arc sitiiutc<l in tlic iiitcniiil car iiisidf tlin
^'anjilioii vest ilxilarc (Scarpa's ^fanj^lioii, Kij,'. XW). Tlicsc cells,
whii'li remain bipolar throu^'liout life, wend their peripherul
Trnncu» »ymimthic\w. —
Uanglion cerv. in/eriiu
h'lUK. ifirdiacua I. S. aympathici.
(Ittnylion spinale.
(liiiii/liiDi tiunci
si/miKithici,
Jill mi com III It II ica nte$.'.
(ianiil. iiiiiliiHiiiii iicii'i
Ham. ciii(ti<icuH I,
Ham. iccuni'iin.
H. rariiiitfi vitiji.
R. mill. iiiiuH nympalhici.
I*. Ill III. riifii til /)/('.!■ 110
aortifUH thiiiuriiliii.
H. mill, miii to coniiectinij
plvxiia.
H. caril. vaiji to iitrial
j>lexu».
Fio. 330. — Syinpalliii'iis and N. vaRiis of a liuniaii cniliryo vit'wcd from tlif ri(;lit
side. lAt'lcrW. His, .liiiiior, and ,1. Kullniann, frinn Kollniann's Lt'lirliucli
del- F-iitwickcliiiiKsKcscliiclilc dcs Mcnsclitii, Jena, IHIIH, S. rMl Kin. :{:5ti. I
prolongations to the vestibule and seniicircnilar canals, especial-
ly to the macula aoustica utriculi and to the cnstse ampuUares
of the superior, posterior, and lateral membranous ampullw
{V'lg. XVi). These peripheral fibres, after repeated divisioJi, all
end free * in an)ong the hair cells situated there, coming only
into Qontact relation with these cells (Retzius, f van (Jehuch-
1 ' ^^ I
* The observations of II. Avers — A Contribution to the Morpholofjy of
the Vertebrate Kar, with a Reeoiisideratioii of its Functions. J. Morphol.,
Host., vol. vi (18!)2), p|). l-3(iO; Teber das peripherische Verhalten iler
(iehiirnerven und den Wert der Ilaarzeilen des Geiiororganes. Anat. .\n/,.
.Icna. Wil viii (1892-'0:i). S. 435-440— who formerly, at least, lielieved that
aeoustie nerve filires arise directly from the hair cells, is in disagreenicnl
with the findings of other investigators.
+ iJetzius, 0. Die Kndigungsweise des Gehi^'nerven. Biol. I'ntersuch.
*Stoekholin, n. F., Bd. iii (1892), S. 29-30.
!:-fPrll
w^
500
THE NKKVOUS S VST KM.
ten,* Hiimon y Cajiil,t von Lenhosst''k,J and Krause **). Inas-
much us the endings in the maciihi acustica sacculi (Fig. ■i'-i-i)
correspond closely to those in the macula acustica utriculi, tlu'
AVrci/.s riifhltip.
Servus vixtihuli.
Nervns fdciolis.
danijUon vestibulare.
(Itiiiijlioii tjenicnU.
(ianylion spirale.
Systeniii ticn'oniin
rvntriilv.
JiecfSHUn lubyrinthi.
Ductus si'iiikhcultirin
IHisterior.
Durtiii sfiiiicircuUiiis
l{itii(ili>i.
I'fricnliis.
Sacotlus.
— ' - • Diu-tns cochlearis.
'•""-■i.iir
ri(i. 331.~-Ii('ft iiuditory vesicle with the aciistico-tiiciiil (•(nniilex dCa hiiniaii ciii-
liryi) iit the liltii weeli. i After His, Juninr, fniiii K.illinaiiirs text-lieok, S.
.>»(), Kifr. ;w:5. >
(juestion may naturally be raised as to whether the saccular
branch of the nervus cochleic really may not subserve the same
functions as we now attribute to the branches of the nervus
vestibuli. In tlie latter event it would perhaps be justifiable to
remove the neurones corresponding to the nervus saccularis
from the group of peripheral auditory neurones, and to in-
clude them with the group at present under consideration.
The central prolongations of the cells of the ganglion vestibu-
lare, united into a compact mass as the nervus vestibuli, enter
the central nervous system at the junction of tho medulla and
* van (ielmchlcii, A. ('oiitributions i\ Telude des ganglions eerehro-
spiiiaiix. Hull. Aead. my. d. se. de Tielp., Tiriix., :{. s., t. xxiv (1K!)2), jip.
llT-ir)4.
t Rainoii y Cajal, S. El nuevo coneepto de la histologia de lo.s eeiitros
nerviosos. IJev. de eieii. med. de linrcel., vf)l. xviii (1802). pp. ofil-;i7(>: and
pp. 45T-4T6.
I von I>en]iossek, M. Die Xervonendigunfjen in den Maenlu' und Cristie
acnstica'. Anat. Hefte, Erste .\htli.: Arh. ans anal. Inslit., Bd. iii, Ileft
0. S. 2:!1.
* Krause, H. Die Endi}runf.'sweise des Xerv. Aeiistieus iin Gehiirorgnn.
Verhaiidl. d. anat. (Jesellsch.. Jena. M. x (18!)6), S. 105-17:5.
(il{OL'lMX(} AM) fllAlNIXd T()(}l>yrHKR OF NEUUUNKS.
1 i , 1 1
the pons as the vestibuhir root of the
acoustic ncrvi' (radix vestibularis X,
acnstici). Tlic (lenioiistration l)y von
Hi'cliterew* in 1SS5 of the existence
and anatomical independence of two
roots to the nervus a(!usticu8, one
(posterior and lateral) connected with
the cochlea, tiie other (anterior and
medial) connected with the vestibule
and semicircular canals, formed the
starting point of the series of inves-
tif^ations which have gradually solved
the uiuch-vexed questions concern-
ing the origin aiid central connec-
tions of the "acoustic" or eighth
nerve. Von Hechterew's researciies
fouiul a most important confirmation
and extension in the investigations
of llis.+ This root enters at a point
farther anterior (cerebral ward) than
does the cochlear root. It is also
situated medial to the cochlear nerve,
and after entrance passes obli(|uely,
medial to the corpus restiforme (be-
tween it and the tractus spinalis
nervi trigemini), in a dorsal and me-
dial direction towaril the tloor of tiie
fourth ventricde. A little lateral
from a point midway between the
median line of the medulla and the F
lateral margin of the corpus resti-
fornu' at this level, the root fibres, as
von Kolliker and Held have shown,
undergo bifurcation, dividing into a
coarse descending and a more deli-
cate ascending limb. This bifurca-
<i. 33:J. — Sclx-iiu' of ))cri))li('riit
tcniiiiiiitiitii (if N. vtsiilmli.
(After (i. Kctziiis, Hii.l. I'li-
t<'rsu(li., Stockhdliii, 11. I'".,
Hil. iv. ISi)-^, It. "iti. V\fi. 7.1
<•(*, ('('iitrii! nervous syst<'iii :
/;. (leliciite sll|ilmrtiiiK cell;
hs. liiiir cells: s)i, axmie of \.
vesliliiili: .S-, ]perikiiry<iii nt"
vestiluilar neurone in the
gunglion vestihuliire.
* Beclitcrcw, \V. Ueher die iiinero Abtheiliiiif; <le.s Strickkoqiprs tmd
den iifhtcn Hirnnerven. Noiirol. f'eiitrallij.. r.eipz.. Hd. iv(188r)). S. 145-147.
■f Mis, \V. Zur(iL'SL'hifhte i\n (icliinis sowie der eeiitralen uiid peripher-
isehcn Nervenbahiien. Ablin "' 1. iiiatli.-pliys. CI. d. k. .siielis. (iesellscli. d.
Wissenseh.. Li'ipz.. n. F. 135 (lH^t^^). M. \\v.
I
i
\l
if
t
i
rraif^
r.02
THE NERVOUS SYSTEM.
tioii is exquisitely demonstrated in one of Kunion y ('ajul's
preparations (Fig. ;};}4). The descending limbs of the vesti-
bular fibres together nuike up the well-known radix descend-
ens nervi vestibuli.*
llLl;
1 i
Fid. 333. — Isolated iini)iTKiiiit<'(l iiittTcpitliclial cud arliiiri/jitictii frnni tlic iiiaciila
acustica s-icciili. .Mctliod id' (iolfii. (.M'tcr M. von Lciilioti.sok, Aiiat. llfl'lc,
Wicsl).. Hd. iii, licit ix, lSi»3, Taf. xiii, Kis. 3.)
The root fibres of the nerve of the vestibule come into con-
duetitm relation by means of the collaterals and terminals of
their axones with the so-called " nuclei of reception " or tmrU'i
ternniitilcs [Endkerne of the (jermans) of this nerve. In the
descriptions of no part of the medulla has there been more con-
fusion, perhaps, than in those of the region of the nuclei of
termination of the acoustic nerve. The older literature, well
epitomized by Onnfrowicz,t is a mass of the most bewildering
and contradictory statements, which, together with the varying,
* This root, called by Meyiu'rt the innere Ahtheilung dcf Strickkdrpem,
was carcfJly stiKlicd and dosoribcd by C. F. \V. Uollor — Eiiic aiifsteij^eiidc
Aeiisticuswurzel. Arch. f. niikr. Anat.. Bonn. Hd. xviii (18H0). S. 403-40H;
and In Sachondprauf.'<toipcndcn Aciistifnswtirzel. Arch. f. Psyehiat. u. Xer-
vcnkr.. l?crl., TM. xiv (188;^). S. 4r)8-4(U) — but was erroneously desiirnated by
hini (lufsffii/i'tuli' Wiazi'l. He believt^d that it ha<l it.s orijjiii in the fascicu-
lus cuneatiis.
t Onufrowicz, R. Kxperinientelier Heitrafj^ zur Kenntniss desUrsprunps
des Nervus acu.sticus des Kaninchcns. Aruli. f. Psyciiiat. u. Nervenkr.. Hcrl.,
Bd. xvi(1885),S. 711-742.
■
I ■ '.;i
i!'i
I'^t!!
OKOUPINU AND CHAINING TOGETHER OF NMUllONES. 508
1
^^■i
ill
'it
iiil
#1-
Vm. ',VM. — Lateral sjinittal section tliroUKli the rlioiiiln'iieeplialoii of a IVelal
mouse. (After S. Haiiioii y ( 'a.jal, Heitraj; ziiin Stii(liiiiii tier Medulla < )l)loii-
fjatii, etc., Leip/.., ItiMi, S. ti;5, Ki^. I".' The seetiou is relatively thick and
shows (listiuctly Hit liit'urcatiou of the root lihres of the N. vestihuli. n. root
tihres; h, ascenilinj; liiuhs; ./'. coutiuuatiou of ascentlin;; liinhs into lUU'leus
N. veslihuli sujMM'ior , liechterewi auil nucleus cerehelloacusticus ; c. tlescenil-
xun linih of larfje calihre ; </, collatenils terniinatiu}; in inicleus N. vestihilli
spinalis.
Ul^-y
u.
r)(»4
TlIK NHIIVOUS SYSTEM.
ovcrlai)!)!)!^', iind iiu'diisccjiu'iit iioniciicliiturc omployt'd, liave
iuii(l{^ tli(! older articU's so puzzling as to ri'iidcr tliciii almost
wtn'thU'ss to the student of to-day.* I shall not attempt, there-
fore, a tedious rrsinneoi the hibliograpliy, hut shall state as sim-
ply as possible my own views regarding these nuclei, which have
heen fornic<) .;fter study of serial frontal, and hori.-'ontal sections
through the medulla of the fcBtus and the adult with Miss Flor-
ence Sahin, and after a careful comparison of our findings with
those of von Bechterew,f Flechsig,;}; Har,inski, * von Mouakow,||
* Tlie cxtreiiip complexity of tho parts and tho limitations of teclini<iii''
of till' period oxciise the lal>yriiitli of errors into whicii the oldi-r investiga-
tors wert' led. Amid the pMieral confusion a reader of the oUier arlich-.-.
can not help beinjj impressed with the careful objectivity of the descri;)-
tions of tlie j^reat Knjjiish neurologist, J. Loekliarl Clarke (I{esearc''es
on the Intimate Structure of the Hrain, Human and Comparative, lull.
Tr., Lond., vol. exlviii (1858), pp. ^IJl-'J")!). — Researi'lies on tlie Intimate
Structure of the Hrain. ibid., vol. dviii (I8(»H), pp. 2(i;}-;5;il). Tiie pulili-
eations of John Dean, of Hoston (The (Jray Substance of the Medulla
Ohlonjjata and Trapezium, 4lo, Smithsonian Conli'ihutions to Kno\vled>,'e,
\Vashinjj;ton, 1H64), show excellent illustrations of the region in (juestion.
The orij,'inal articles of (). F. C. DeittTs (rnlersuchnnf;;en nciier (iehirn
uiid Hiickenmark des ^lenschen und der .Sihigethiere, nach dem Todo
des Verfassers heransgegeben und bevorwortet von Max Schultzo, 8\-o.
Mraunschweig, 186")) should be consulted by any one wishing to under-
stand the position taken by this celebrated neurologist concerning the
nuclei in ({uestion.
+ von Hechterew, W. Ueber die innere .\btheilung des StrickkCirpers
und den achten Hirnnerven. Neurol. Centralbl.. Leipz., Bd. iv (1885), S.
145-147: [Origin and Course of Stria' medullares s. acustica\| .Aled. Obozr.,
Mosk., vol. xxxvii (1892), pp. 470-478; also in Xeurol. Centralbl., Leipz., Hd.
xi (1892), S. 297-;505.— Der hintere Zweihiigel als Centrum fiir das (Jehur, die
Stimme und die Reflexbewegungen. Xeurol. Centralbl., Leipz., Bd. xiv
(1895), S. 706-712.
X Flechsig. V. Zur Lehre vom centralen Verlauf der Sinnesnerven.
Neurol. Centralbl., Leipz., M. v (1886), S. .545-551.— Wcitere .Mittheilungen
uber die Heziehungen des unteren Vierln'igels zum llornerven. Neurf)l.
Centralbl., Leipz., Bd. ix (1890), .S. 98-l(i(t.
* Baginski, B. Ceber den Trsprung und den centralen Verlauf des
Nervus acuslicus des Kaninchcns. .\rch. f. path. Anat., etc., Berl., Bd. cv
(1886), S. 28-46. — Ueber den I'rsprung und den centralen Verlauf des Nervus
acusticus des Knninchens und der Katze. Arch. f. path. Anat., etc., Berl.,
Bd. cxix (1890), S. 81-9:}.
II von Monakow, C. Ueber den Urspnmg und den centralen Verlauf des
Nervus acusticus. Cor.-BI. f. schweiz. Aerzle, Bd. xvii, 1887, No. 5; abstract
in Neurol. Centralbl., Leipz., Bd. vi (1887), S. 201.
Ill
iti
, 1!" I
(Jll()UlMN(} AND CIIAININ'C TodHTIlHU OK XKl'WoNKS. 50.-)
Salii,* IIol(l,f P. Murtiii,J Cramer,* Kiiinoii y ('ajiil,|| and
otlicrs.
Tlicre aro, in accordaiico with tlio views of tlie majority of
recent investigators, at least four well-defined ])riiuary nuclei
of tormination in connection with the vestihular nerve: (1) The
nucleus norvi vestibuli medialis (Schwalbe) ; {'i) the nucleus
nervi vestibuli spiuiilis (radix deseendens) ; {'.]) the nucleus
nervi vestibuli lateralis (Deiters); and (4) the nucleus nervi
vestibuli superior (Flechsi'g, von IJechterew). In addition, the
nervus vostil)uli comes into direct conduction relation, {(() (prob-
ably chiefly l)y means of collaterals) with the nucleus nervi
cochlea} ventralis; {//) (by means of ascending liml)s of divi(h'd
root fibres or collaterals from these) with the mass of nerve
cells (Ramon y Cajal's nitrjt'us rcrrhcllo-ariixtirnft) in the lateral
wall of the ventricle, dorsal to Hechterew's nucleus, and (')
with the nuclei of the roof of the fourth ventricle (nuclei fas-
tigii) on ])()th sides of the middle line, and [il) possibly, accord-
ing to Ramon y Cajal, by means of a few fibres with the nucleus
ilentatus cerebelli and the cerebellar cortex.
Concerning the exact topographical relations of the four
principal nuclei, the descri),)tions in the I)ibliography are not
only very incomplete, but there is also considerable variance
between the statements of ditt'erent autiiors. Florence Sabin
has made from serial sections a flat reconstruction of the exact
limits of these nuclei as they exist in the new-born babe, and we
* Sala, Ij. Siir rorif^inc dii iicrf iicoiistiiiuc. Aicli. ital. tie Ijiol., Turin,
t. xvi (lH!»l-"!)-->), ii|i. 1!m; -JO?; also in JFonitore zool. ital., Firenzc, vol. ii
<1891). j). -IW).
t llelil. II. Die cfiitialcu Balmoii ili's Nervus acusticus bei der Katze.
Areh. f. Aiiat. and Pliysi..!.. Aiiat. Ahtli., Lfij.z. (1S!)1), S. 371-201.— Die
Endij^uiijjswcise der seiisi!)leii Nerven iiii (n'liirii. Arch. f. Aiiat. u. I'liysiol..
Aiiiit. .Vhtli.. Leipz. (1S!»2), S. I};j-;i0. — FoImm- eiiie direote aeiistisclie Kiiideii-
balin und don Ursprunij dcs Vorderseitenstnin,i,'os helm Mensclien. .\rcli. f.
Anal. 11. I'liysiol.. Anal. Alitli.. Fieijiz. (1«!)3), S. 3r)7-2(;4.— Die ceiilrale Ce-
horleitiinf,'. Arch. C. Anal. 11. Physiol.. Anat. Ahth.. Leipz. (IHiKi). .S. ^Ol-'ilH.
X ^lartin. I*. Ziir Hnditruiif; des Nervus acusticus iin Gehini der Katze.
Anal. Anz., .lena, lid. ix (lH!):i-"!»4). S. 181-184.
* Cramer. .V. I{eili'!i;,'e zuin feincren Anatonii(> der Medulla otilongala
und der Mriicke mil liesonderer IJeriicksichtif^nni,' des ;i-I2 llirnnerven,
Jena. 181)4.
I! Hamon y Cajai. S. ISeitriiir ziim Sluilium der Medulla ohjonirala. des
Kleinliirns und des I'rsprunu- der tiehirnnerven. Deutsche I'eiierselz. vuiti
Hresler, Loii)zi-,'. l.S!)(5.
Iti
ii
506
TIIK NKllVOL'S SYSTEM.
1:1
Flo. 3155.— DiiiKnmi rcpn'spiitiiifr flat rcconstriictiDii of the nuclei iif teniiiiiatinii
of tlieciiclilcaranil vestibular nerves, i After Florence li. Sal)iM,.lolins Hopkins
Hosp. Hull.. Italt., vol. viii. isit", Fi>r. 1. i Tlu' line a. n npicsents tln' lat-
eral wall of tile ventricle ; the line h corrcs|ion(ls to llic lateral outline of the
corpus restiforiiu' ; the line il\ to lU. ili to ''a, and the line <■. f. c corresi)on(l to
tlu' sulci in the tlo(U' of the fourth ventricle: ('.</., nucleus nervi cochhie
(lorsiiiis; ('.v.. nucleus nervi <iiclileie ventralis : the jjrailuated line ciu-
responds to the middle line of the tloiu' of the ventricle; Fine, lloceulus;
A'. 17/. kiu'c of nervus facialis; /,.. medial portion of nucleus ner\ i vestihuli
iatenilis iDeiters); /,i, lateral portion of nucleus m-rvi vestihuli lateralis
( Deiters I ; .1/. together with }', nucleus nervi vestihuli medialis iSchwalhe ;
Sue. XII. nucleus nervi h,vi)of;lossi ; Sue. VI, nucleus mrvi al)duc<iitis ; I'. J'.,
peduniiilus llocculi ; A.m. /(.!'., nucleus niotoriiis ](riucci)s mrvi tri^reniini ;
A', o. .v., nucleus olivaris superior ; S.x.V., ninleus mrvi tri^'cmini (sensiu-y);
A', v.. root liundle of nervus cochhie ; A', ffnt.. root bundle of nervus vestihuli ;
R.d.n.n.. i"adi.\ descemlens nervi vestihuli; .s'., nucleus nervi vestihuli
.superior ( Hechterew I larea inclosed in the broad black line); Tr.s.ii.t.,
tractns spinalis lU'rvi triKcmini ; )', nucleus //, = antero-latei'al jHUtiiui of
liuclius nervi vestihuli medialis; c, deeussatio nervi triyeinini.
UROUPINa AND CllAININM} TOGHTIIKR OF NKUHONKS. 507
are presented for the first time in her article * with a diaf^nini
which shows clearly (at least in two dimensions) the size and
relative positions of the nuclei. Miss Sahin's diagram is repro-
duced in Kig. ;5;55.
It will be seen in the diagram (Areas M and Y) that the
large nucleus nervi vestihuli medialis, beginning spinalward a
little above the middle of the nucleus nervi hyi)f)glossi, extends
cerebralward to a level corresponding approximately to the
spinal extremity of the nucleus nervi abducent is. its medial
border reaches almost to the median line of the floor of the
ventricle, going over without sharp limit into the central gray
matter, while laterally it fuses with and is with difficulty distin-
guisliable from the nucleus nervi vestibuli spinalis (radix de-
scendi'us). The latter nucleus is made up of great numbers of
ci'Us situated in the gray matter surrounding the descending
root, and also of many cells interspersed among its liiircs. The
fibres of the descrnding root, as the cross section (Fig. -VM't)
shows, are arranged in small bundles among which gray matter
rich in cells is everywhere distributed. The nucleus of the de-
scending root represents at least one of the principal, if not the
principal, end-station of vestibular fibres. f
The antero-lateral extremity of the medial vestibular nucleus
(Miss Sabin's nucleus Y) is undoubtedly the most im])ortant
part of the medial nucleus. In transverse section, nucleus Y is
triangular in shape with the apex ventralward, hence the name
iiKch'iis fn'(ni(/iil((ris given to it by some authors. In it arc
situated an enormous number of cells closely crowded together,
in among which ramify very many rather fin(^ meduUated fibres
from the area in which the nervus vestibuli bifurcates. The
nucleus Y tapers out posteriorly, and finally disappears ante-
riorly just medial to the wide part of the medial portion of
♦ Sabin, Florence R. On the Anatomical Relations of the Nuclei of FJe-
ee,>tion of the Cochlear and Vestibular Xcrves. Johns Hopkins liosp. Bull.,
Halt., vol. viii, 1897, pp. ^oS-^,-)!!.
f It is rather amusing to find that in the earlier history of the vestibular
nuclei the medial nucleus was spoken of by Schwalbe as the Ilaiiptkern dcs
AcusticHS. Later the superior nucleus (v. Hechtcrew) was described as the
Ilaupfkcrn di:s Acusttcus. It would be unfortunate if, in ajjreomint with
Hamon y Cajal and myself, still others, coming to the conclusion tliat the
nucleus of the descending root is the principal nucleus, should introduce a
third Ilnuptkern des Acusticas !
I
ii
5
-7
I
f
tin
H ?
,i
\'
r)OS
TIIH NKUVors SYSTKM.
Deiters' nucleus as shown in the (liiif^nuii ( Ki<^. :{:}")). Posterior
to it (that is, spiiiiihviinl from it) is situated the nueleus of tiie
dosccndinf^ root, and tiic Junction of tiu' two nuclei is nuirked
by a re^uhir vortex of fine inedullated fibres.*
Kuavm
Nuu.
K'joam.
Fio. 33(5. — Tr.msvcrso section of incdtilla ohloiiKitta and ('('rchclliini of n('\v)»irn
child. (Scries ii, section N'o. lt(i. ' r.r., corims restifornic (tlie part nu'dul-
latcd correspon<ls in the main to tlic direct <'ereliellar tract): !■'.'.. liiindle
continuous with tile fnniciiliis lateralis of the cord: F.l.m., fasciculus lonjti-
tudinalis inedialis; .V./.V..V.. N'. srlossopharynneus et vajjus : S.Xll., N. Iiypo-
nlossus: Sii.d., nucleus tlent:itus : Xii.ii.c.d., nucleus \. coclilcie dorsjilis;
Xii.ii.r.iii., niu'leus N. vestiliuli niedialis : Xii.o.n.d.. nu<'leus olivaris a<'ces-
soriiis dorsalis: Xn.o.ii.iii., nucleus olivaris accessorius inedialis: Sn.o.i.,
nuchiis olivaris inferior; Xit.f.s., nucleus traclus solitarii : /'.7'.. ixdunculus
llocculi; /'(/., pyraniis : I'.d.ii.rfst., nidix descendens N. veslilmli: St.i.t..
stratum interolivare leninisci : fi'i, plane of longitudinal section No. fi(i.
[NoTi;. — This lifjure has heen (lispro|Mirtionalely reduced in the reproduc-
tion.] (Weifjert-I'al preparation hy Dr. Joiin llewetson. i
* Sabin, F. R. (op. eit.), hits riphtly laid eniphiisis npon the individuality of
nucleus Y, adducing as her reasons (1) the size of the cells (larger than those
of the rest of the medial nucleus, sinaller than those of Ueiters" nucleus);
(3) the mode of staining of the mielous (niucli darker than Deiters' nucleus
proper in suitably diirerentiated Weigert-Pal preparations); {',]) the dis-
tribution of the cells (closely packed together in Y, .scattered and far fewer
in number in Deiters' nucleus), ami lastly, (4) its distinct deiinirkatinn from
the adjoining gray ma.sses. She does not assert its absolute morjihohigical
independence, but is eontcnl with outlining its position and calling attention
1o its characteristic features.
,
f
OIIOI'I'INO AND CIIArNIXd TOCJHTIIKR OK NEUUONKS. 5()j)
Till' miclt'U.s norvi vi!stil)uli superior ( Flecilisif;, v. Hcchte-
rew) is represented in the (liii^'raiii by tlie urea S, outlined by
the very heavy bluek line. It be<,Mus posteriorly at a level
somewhat behind that of the anterior end of the medial nu-
eleus, but is ])la('ed much more laterally aiul dorsally, so that it
lies in reality in the lateral wall of the fourth ventricle and in
the ventro-lateral angle of this cavity rather than in its Moor
(Fig. X\7). At the inferior end it is intimately (connected with
the libres of the pedunculus flocculi ; inchuMl, its lower limit
is only with <freat ditliculty determined, owinj^ to the intimate
admixture of fibres and cells. At its upper (anterior) extrem-
ity it tapers out into a narrow mass of cells which can he fol-
lowed anteriorly as far as the level of the princii)al motor nu-
cleus of the lU'rvus trigeminus. The main mass of the superior
nucleus of the N. vestibuli is ventral aiul medial to the ventral
portion of the braidiiuni conju?ictivum. At its lower (poste-
rior) extremity it is medial aiul dorsal to the corijus restiforme,
where the latter turns up into the cerel)elluni. dust anterior
to the point in which the connection of the jieduiiculus flocculi
with Bechterew's nucleus is most ai)parent the nucleus lies ven-
tral to the corpus dentatum and dorsal to the corpus resti-
forme, being intercalated, as it were, like a buffer between these
two structures.
The nu(!leus nervi vestibuli lateralis (Deiters') is situated
between the medial nucleus and Bechterew's nucleus, lateral to
the former and ventral and somewhat medial to the latter (Fig.
;3:57). Miss Sabin's diagram shows clearly its division into two
parts, L and L,. The portion L is situated in front of (anterior
to) and medial to the portion L,. I would suggest that these
two portions of the niu-leus nervi vestibuli lateralis be desig-
nated, temporarily at least, as the /'ars metlialiti (L) and Pars
hifprah's (L,). I wish to lay stress, however, upon the fact that
the subdivision of Deiters' nucleus here made, refers only to
relatively gross relations, for microscopic examination shows
that the two parts are in reality nuule continuous with one an-
other by a few scattered cells which are interspersed among
the root fibres of the nerve. The cells in L and Lj are very
large multipolar ganglion cells, closely resembling the cell
bodies of the lower motor neuroiu's (cells of ventral horns in
spinal cord, motor nu(dei in medulla). The study of serial sec-
tions shows very clearly the remarkable relations of Deiters' nu-
34
v
Mm
r, 11
Mh
510
TIIK XKKVOrs SYSTKM.
^ >'< < ;5 .5 ? ^ -i.'i .c S'C £ k
.w ^— 2
>' f^i
m
Pi, t'
ri'
^ 2- >:u|i;f^ 3 ; Kvi?
= s = A ~ i<' 2 r - c - '■ . • s >^
i
'•
(iU<>l'lMN(t AM) CIIAININCJ TOCJKTIIKIl <»P NHrUoNHS. r^\i
(lens to till' vcstihuliir roctt libiTS. Tlu' til)r('S i'nti'riii<,' as ii
toU'nibly coinpiict bundle pi'iu'trate the iiii'dulla to the re^'ion
of this nucleus, and tiien, suddenly stoppiiifj their dorso-niedial
course, hifurcate, the eoarse descendiMj; liiiil)s passin<r iininedi-
iitely tlownward after division in the radix descendens nervi
vestihuli. The diagram (Fig. :{;5*>) shows how Deiters' nucU'UK
(Ii„ L) sits, as it were, like a cap upon the dosceiuUng root. The
medial jjortion of the nm-leus L is separated from the lateral
portion L, by the entering root flbres.
•Inst how far down the fibres of tin- descending root go it is
ditlicult to say. They can certainly be followed to a level pos-
terior to the middle of the nucleus nervi hypoglossi. Hamon y
Cajal has been able in the mouse to follow them below the gan-
trlion commissurale of the tractus solitarius.
What is the fate of the ascending liiid)s of division of the
axones of the nervus vestibuli ^ The careful studies of v.
Ki'tlliker, Held, and Ramon y C'ajal with (lolgi's method have
determined their course. They pass in a (b)rsal and somewhat
lateral direction, pursuing a tortuous .nid very irregular course
into the nucleus nervi vestihuli superior, where all of them give
off numerous collaterals and many of them eiul. The coarser
Hbres among them i)ass up medial to the corpus restiforme ami
terminate in the cerebellum in the nuclei of the roof of the
i'ourth ventricle of the same and of the opposite side, and, ac-
cording to Cajal, give off in passing collaterals to the little
mass of lUM've cells situated in their course (his uuch'ttx rrrc-
hcUi) oritsfini.s). The fibres of the direct cerelx'llar bundle of
the nervus vestihuli are doubtless among the l)undles of medul-
lated fibres seen in Fig. :]:i7, exteiuling between the region of
Deiters' nucleus through Hechterew's jiucleus and the brachium
conjunctivum to the region of the nucleus fastigii, though they
do not represent the majority of these fibres.* It is impossi-
ble, however, from Weigert-Pal preparations to say in every
instance in which direction the fibres are running — whether
from the medulla to the cerebellum, or from the cerebellum to
the medulla.
The connection of ascending limbs of vestibular fibres with
the medial nucleus (its antero-lateral extremity, nucleus Y)
r
If
* For a study o( the nucleus fastifjii hy (idliji's method, see Hainoii y
Cajal. Ganglions eerebclleux. Bibliogr. anat., Par., t. iii (1895), p. 33.
:i
¥■■:
» 1
i*I
512
TIIK NKHVOUS SYSTKM.
mill with DcittTH' luicli'iis appcarH to lie mainly l>y incuiis ot'
collatcralH. In Wcifjc't-I'al prcpuratiotis cnoriiiourt nunilxTs ut'
fibres are scon to enter nueleus V, hut it is iinpossihle to say
Fks. 3:{H. — I'criccllnlnr riidiiiKs nf (■(illiilcriils IVinii the iixoiics nf tlic N. vislili-
illi ill the iiiiclciis N. vcsliliiili lalcnilis iDcitcrs') of a I'niii-dii.v-iiM cat.
( After S. liaiiii'iii y < ajal. IJcilraK /.iiiii Stiidiiiiii dcr Medulla < )l)lnii).'ata. etc.,
Lei|)/.., ISiMi, .'^. '2. V\fi. Mil.) .1. de.seeiidinj,' liinl> cd' Idl'iircatimi of N. ves-
tiliuli ; //. iiericelliilnr iietwcnk ; (', liiaiudies in wliiili niie can see the
teriiiiiiaticiiis id' the ultimate lihriis ; if. cidlateral whiili. eiiteiiiiK into n iii't-
Wciik. sends aimthei- coMateial I'd to iieii;lilMirinK raniilications.
whether these are colhitenils or ascendinji; limbs of divided root
fibres. The lower portions of the medial nnelena reeeive
numerous collaterals from the deseeiiding limbs running; in the
radix deseendens. A jjreat many collaterals from the fibres of
the descendin<r root end in Dciters"' nucleus, where they form
most complicated pericelhdar ])lexuses ( Fi<f. ;{:5(S). The ma-
jority of the collaterals and terminals of the descendin<j limbs
end, however, in the gray matter innnediately adjacent — i. e.,
in the nucleus nervi vestibuli spinalis. Ramon y Cajal insists
P
:
ii
OUOLMMNd AM) CIIAININC} TOOKTIIKII OK NKl'UONKS. 5i;}
that the itniunicniinc (•olliitcruls of the <l('S('on<1in<; root form
witlioiit tloul)t tlic cliicf tcriiiiiiiition of tlic V('stil)uliir iicrvf.
A very wclconic coiifirmiitioii and cxti'iisioii of inodcni views
concorniiif; tho (listrihution of tlu' root fibres of tiu' ve8til)iilar
lUTVi' lias l)('eii funiislu'd hy 'riioinuH.* 'I'lie reader is referred to
liiHexperiiucnts ii) wliicli lie cut, t lie root and sul)se(|Ueiitly studied
the (listril)Utioii of the hlires liy iiieaiisof tiie iiu'thodof Marchi.
The Htuih'iit of the microscopic iiuatotiiy of the medulla ob-
loufjiita ean not fail to be impresseil with the importutice of
these complex ^ray masses in connection with the collaterals
and terminals (»f the axoiics of the peripheral vestiluilar neu-
rones. Such an elaborate end-apparatus in a re<,Mon where
^•rr^
Flo. Ml. — f Jiiiiuliiiii fjciiiculi of a ni'wlnn'ii inoiisc. (After ^l. von I.ciihos.s('k.)
riiilioliir iirrvi' cells uiviiiK oll'ctnlral axoiics to the N. iiilcriiiiiliiis ; ii, jioiiit
of liifiircation ; />, isoiatcd fihrooftlu' N. pi'trosus siipcrficialis iiiajor.
space has been economized to the utmost must be of the liigli-
est physiological significance.
The central uxones of the cells of the geniculate ganglion f
* Tlioiiios, A. Les terininaisons centrales Ue la raeine labyriiithique.
Compt. rend. Soc. de biol., I'ar.. 10. s., t. v (1898). pp. 183-185.
f Tills jjanglion in early embryonic life is a portion of tlie general fan-
shaped (UxntjUan iicu.sfirofocinh' of Ilis. 'i'he (•('ntrii)etal (ilires arising
from this ganglion decussate at the apex of the triangular ganglionic mass,
and enter the medulla in the form of two hundh's — a lateral and a medial.
The peripheral fibres diverge as the co('hlear and vestibular nerves. The
motor facial nerve, whose cells of origin are inside the pons, breaks through
this ganglioinc mass, carrying with it the group of cells corresponding to
the geniculate ganglion. Cf. His, VV. Die niorphologische Betrachtung
■•, I,. I
|.i
M
■ t
\
m\
jMiiilMiii
■"i
^i I
514
TIIK NERVOUS SYSTKM.
(nervus intormodius) join, in all probability, the intracentral
prolongations of the N. vagus and X. glossopharyngeus. Tiio
poriphi'ral axones accompany, in largo part at least, tlie bundle
of motor axones which constitutes the N. facialis (Fig. '.V.V,)).
The cell bodies of the sensory neurones of the tit'nui.s tri-
ffeniiiiiis are situated in tlie ganglion semilunare ((«asseri)
(PI. I, Fig. -2). They are unipolar, like the cells of the spinal
ganglia. Their luedullated central axones form the portio
major of the lifth cerebral nerve (Fig. liiO). The peripheral
processes of the ganglion cells are distributed to the skin of
the face and the mucous membrajie of the mouth. The cen-
tral prolongations plunge through the substance of the pons
into the region of their nuclei of reception (Fig. ;541), where
they bifurcate * (Fig. '-U'i), being thus distinguishable from the
motor fibres of the fifth nerve, which do not bifurcate. f The
descending limb of bifurcation is coarse; the ascending is fine,
and termimitcs after rather a short course in that portion of
the substantia gelatinosa often spoken of as the main nucleus
of rece})ti()n of tb.' sensory portion of the trigeminus. In real-
ity this is only the much expanded upj)i'r portion of the sul)-
stantia gelatinosa. The descending limbs pass a long way down,
the medullated axones forming the well-known tractus spinalis
ncrvi trigeniini,J which runs through the whole length of the
(lor Kopl'iiiTvcii. .\rcli. f. AtiMi. u. Pliysiol.. ,\nat. Abtli., Lei])z.. 1887. S.
;i79-4"):5: mikI His, ,Ir., \V. /ur Eiitwickfluiii^sgfschichU' di's .Vcustico-
Fiiciiil.tct'hiftcs iR'iin Monsclion. Arcli. f. Aunt. u. I'liysiol., Aiifit. Al>tli..
188i), Suppl.-I5(l.. S. 1-28.
* Tlie i)ifurcjiti(in of tlio sensory axouos of tin- \. Injjfcinimis observed liy
Raiiu'iii y t'ajal ((iac. sun. de Harcel.. 10 April, KS!)1) lias been conlirined by
von Kolliker, Held, and van Gehuchtcn.
f In Weigort-I'al i)reparat ions the sensory filtros of the \. trifjeininns are
of fine calibre, and stain of a bru\vnish-i)lack eolor; the motor axones are
much coarser in calibre, and stain of a deep bhiish-Vilack color.
X Why even the first-class text-books persist in calliiii; this spinal Imndle
the ascendiiifj' root of tlio fifth (the Germans constantly refei-rinj^ to it as
the (HI fn/i'i'i/i'iide WiirzfJ) ] can not understand. 'I'liis is a serious mist ak(>,
and notliinr is more calculated to confuse t'lc bejjjinntM' than the contiiuiance
of such an erroneous nomenclatr"e. The fihwa dcsppiifl : theyan\in fact,
the U'edullated descendinj,' limbs of the divided axones of cell bodies situ-
ated in the Gasserian ijanirlion. I5y naminj;; it the "s|)inal tract of the tri-
peminus." or tractus spinalis ncrvi triiremini. we avoid llii> confusion with
the radix desccndens (mesencephaliea) ncrvi tritjemini. the me(lullaled motor
axones descending from the nuclei motorii minores ncrvi trigemini.
■iS
^■£^
f
GROUPING AND CIIATNING TOCJETIIER OV NEURONES. 515
medulla, going even below the level of the deeussation of
the pyramids. These fibres on their way give oflf great Jium-
bers of collaterals and terminals, to end free in the neighboring
Fig. 340.— Corchrmn, with a portion of the spinal (■cfi, vie from tlic ventral
surface. On tlic rifilit-iiand siilc tln' ventral roots , t oil' short and
turned niedialward. ( .Vfter Kii<liii;,'er and Ilenle, fi . Kauher's ti'xt-
liook. 1 /. tract us olfactorius ; //. tractus o|(ti' us ; ///, ^', ocnloniotoriiis ;
/ r, N. trochlearis; I'. N. triKcininus. portio major et portio minor; 17. N.
ahducens; 17/. N. facialis; 17/'. N. interiuedius; 17//. N. acusticns; /.V,
N. Hh'ssopharyu;.'! 's ; ..N. vagus; A7, N. acces.sorius ; A7/, N. liypoglossus ;
nc I, N. cervicali ,i.iinus.
III
i
1
1
i
t 1
516
THK NEIiVOUS SYSTEM.
iri
f;
^; ' ~ 91
1,1
1 i
Ml
t k-
Hn
k
^
GROUPING AND CHAINING TOGETHKR OF-^ XEFHONKS. 517
substantia gelatinosa, which in reality forms a continuous col-
umn of nuclei of reception for the fifth nerve, designated now
as the nuclei tractus spinalis nervi friyemini (Fig. 3-43). The
fibres of this tract are very characteristic in transverse sections
stained by the Weigert-l'al method (Fig. 344). In the medulla
Att. III. III. n. V,
FUi. 342. — Sclicnic sli(p\viii« the nidtur niid sensory nciirmu's, the axonosof wliiclt
filter iiitii tile t'liniiiitidii (if the N. trineniiinis. (After. \. van (ieliuelileii.
Auiitiiniie (les systenie iierveiix de I'linninie, Limviiiii, lsi»7. p. hV.i. Ki;;. ;5S4. )
(!..•'. a.. fi'lUKliiiii seniillliiiire (iasseri ; Sii. in. in. ii. I'., nuclei nintiirii niinores
nervi trifieiiiini : .V». m. jir. n. I'., nucleus nietorins iirinceps nervi trij,'<'niini ;
li'iiil. <l<:'<c. iiir.i. II.]'.. radix ilescendi'us [lueseneeplialica] nervi triKeniini : 7V.
.■<;). II. r.. tnietus spinalis nervi tri>reinini.
the bundle is traversed by tlie root bundles of the X. glosso-
])]iaryngeus and X. vagus (Fig. 344), and by some of the tihnv
cerebello-olivares.
Just how far spintilward the tractus spinalis extends there
seems to be a difference of opinion. According to (iudden,* it
Itrobably reaches to the lowermost parts of the cervical cord.
* Gtiddoii. 11. H( itrapzur Koniitniss dor Wnr/.eiii des Trigeiiiinusnerveii.
Allg. /.tschr. f. I\vehiiit., ete., Borl.. IW. xlviii (l^<!n-'«^), S. 10-;{3.
■i,-ii'
!-'
i
^1^1
518
TIIK XKItVOUS SYSTKM.
Oborstc'iiior * puts its lower limit iit, the level of tli(> second
cerviciil nerve, while von KoUikerf states that in the reijion of
tho uppermost eervieal nerves there is no trace of tiie spinal
Fill. :U:{. I,;il( tmI siiiiilliil srrlidii tlifdimli tiic |Miiis anil crrcliclliiiii dl' m I'li'Iiil
II II 11 iM'. slinwini; I lie miimiiv porliiiii c if I lie N. Irificiiiiiuis. ( Al'lcr S. IJauii'in y
(iijal. MiiliMi; /iiiii Studiiiiii ilcr Medulla ( >lilciii;;ala, clc. Lcip/., JsiHi. S. i,
Viil. 1.1 .1. |iiirtiii iiiajiir cir sriiMny imit nl' N. irificiiiiiiiis ; tlif iiidis idiial
axDiio dividing' iiiln an ascriidiiif; [n ) ami a dcsfciidiii^' liiiil) ( /i ) : c. tcniiiiial
liraiiclics (il'asci iidiiii; liiiili ; d, niipt tilirrs wliicli >iiiU iiiln llic dc|itli ; c, dor-
sal liart iit'dcxcnditif; iMUlinii iil' sciisdi-y nmt ; /.', Iiil'iircal Km cif axmirs of N.
voliliiili. Ilic aMciidiny liiiilis ( ;/) t;ciiii;j in tlic (•(•icliclhiiii, the di'Mciidiiiu
liiiilis if) yoiiifi diiwiiwaicl to llif iiitdiilla (ililmiwilii : ''. linicliiiiiii inn
jmicliviiiii ; /', I'asciculiis (('rcliilhiiis ilcsciiidfiis ; /•', ciirinis rcslilDriiu •; /•'.
Iciiiiiisciis lateralis ; //, eurims traiie/oideiilii ; O. iillrleiis deiitaliis.
tract of the triireininiis. A little hiixher (about at tlu' level at
which the dorsal nuclei of the nu'dulla begin) he finds the lower
limit of the spinal tract. Cranier J traces it to the distal I'lid of
the pyramidal decussation.
It has been shown by (ioi<ri's method by Ramon y Cajal in
sagittal sections that the two longitudinal layers of the tractas
* Obprstoincr. IT. Aiileitimf; tieiiii Stiidiiiiii ties Iiaiics (l(>r norvosiMi ('t>ii-
tral-OrpoK' in pviindcn ii. kratikoii /iistiindi'. 'II Anil., Leipzig (181*0).
+ <>/>. ril.. IM. ii. S. -280.
J (>li. n't., S. o;j.
u
liOUl'lNd AND CIIAININO TOUl'miKR OF NKrilONKS. 519
=>§?£/-. §=<>'• t^'^s?!
a S ± •> =
c > i: I ,. =
■L = = = 5.y-
3 -.= •-■- -7, t-- =
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MS —• - '? i _ " •— -£ 2 - ~ ''^'
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1
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520
THE NEIIVOL'S SYSTEM.
Tr.s.nt.
•F.ctoF.r
5,g.
Fui. 345,
ill
l:f
it
i:;M
Fig. 343. — ircirizimtMl scctidii llinm^'li tlic iiicdiillii. pons, mihI niidhniiii ofa iicw-
l)oni l)al)c>. \ViiKiTt-I':il stiiiiiiiij;. licvcl <il' iiiiclciis iicrvi Dciildiiinlorii ami
nu(l<'iis iicrvi triHlilcaiis. ^Si rirs iii. sfctiiiii No. 1(10. i .!(/. (■(/■.. aiiuccliictus
fcrcbri ; llr. rniij., linicliiiini iipii.jiiii('li\ luu ; C./)., foiiiiiiisMiia |Mist<'i'ii)r cere-
bri ; ('. Ilcrlit.. ciiiiiiiiissure lietweeii I'.eclile-ew's iiinlei of the twii sides; C.r.,
eiirpiis restitoniie : /■'./.(». t'aseieiiliis loii^riliidinalis iiiedialis; I'.t.tti /•'.<■.. tilires
frciin rasciiiiliis eiiiieatils t(i loriiial in retieiilaris : /V/). (ice. /'»/.. filiiie areinitic
inteniie : /•'.(■».. fasc. eimeatiis : /■'.<■.((.. I'lpriiialii) reticularis alba ; Mat. l'.. lailix
inotdriiis N. trijieiuiiii ; .V. 17.. radix N. aliducenti^ ; .V. res/., radix N. vestib-
iili : X.l'll.i-.'. radix X. facialis, pars secmida : .\. IXinid X. radices Nii.
HiiissdpbaryiiKei et va^i : X.Xfl. radix N. Iiypnubissi ; A'h.c v /» i. iiliclell.s
centralis superior, pars inedialis : Xii.c.s.ih, nueleiis cent rails sii|)eri(ir. pars
lateralis; .Vc././.. nucleus lenmisci lateralis; .%'»./..'<.. nuideiis lateralis suixrior ;
Xn.ii. III., nucleus N. neulninntcirii ; .V».h, 71'., nucleus N. tmcliiearis ; l..s.,
lemniscus superior; .\ii.f.ii.. nucleus riiniculi gracilis; .Xii.ii.r.r.. nucleus N.
cn( lileie ventralis ; Xii.ii.\'ll. nucleus N. facialis; .s'.;;.. substantia fjelatinosii :
St.i.l., stratum iutcroiivare lenmisci; .S'ji.r.. radix sensorius N. trijjemini ;
St.ij.r., stratum firi.seum centrale; .'<iili. ijrl., substantia fielatiuosa near en-
trance of sensory part of N. Iriiit'ininus; Tr.t<.)i.l.. Iractus spinalis N. trij;em-
ini ; Tr.fr. mi. I)., tract from Deiters' imcli'Us to the spinal cord, i l're|iaralioii
by Dr. John llewetsoii.)
Fid. 'Mil. — 'I'rimsvciX' scrtimi tlmm^'li tlic tntctiis s|iiiiiilis N. Iri;;ciniiii and
iidjaccMt >iili>tuiitin jicliitiiiDSi (il'ii iicwliiirii raliliit. (Al'IcrS. Kaiiiou yCa.jal,
licitnif; /Mill Stiidiimi (Icr Mtdulla ( )liliiiij,'ala. etc.. HrcsU r, \a'\\>7... 1S!)(», S. m,
V'lti- ~. ) .1. vcniral pari nl' Iractiis spinalis ; n, interstitial cells ; c, niavKinal
cells; (/, cell islands ill sniistaiitia fielatiinisa : c, small cells nl' these islands;
/.stellate uiant cells lint ai rallied in islands; ;;, inlerinsiilar cells: //, ll
niai'f,'iiial cell, the axoiie ot' wliicli appeal's to {!<> into tlii' white snhstaiice or
into the tractns spinalis N. tiiKeiniiii.
OUOUPING AND CIIAINIXG TOGETHER OF NEURONES. 521
Fkj. 346.
'1
,-')
1
')•}
i)z
TIIH NKIIVOUS SYSTKM.
spinalis (one siipcrCiciiil aiul (•(tmj)iict, flic otiicr (Ici'pcr, and
consisting of scvcnil hiuulli's separated from one aiiotlier l)v
masses of f,'niy matter) are formed by (leseendiiif? limbs of bi-
furcated root fibres (Fi<f. 'M'.i). Tlie superficial and deeper
layers of tbe tractus spinalis are easily demonstrable in liuri-
zontal sections of tbe rliombcnccpbalon of I be new-born babe,
stained by the method of Weigert-l'al (Fig. ;}45).
The collaterals from the axones of the trigeminal fibres luivo
been carefully studied and described by Hainun y Cajal. He
divides them according to the region in which they are found
into (1) interfascicular collati'rals, (•-.*) margiiud collaterals, and
(;{) nu'dial collaterals. 'I'ho interfascicular collaterals ramify
among the cell bodies lying medial to the su})erficial compact
layer, and ajiiong the fasciculi of the deep layer of the tractus
spinalis. The marginal collaterals, ])assing sonu'times forward,
sometimes backward, ramify among tiie peripherally j)laced spin-
dle-shaped cell l)()dies {lldmlzi'lh'ii) along the bundle of the
deep layer. The medial collaterals unite to form small bundles
which pass through the fibres of the deep layer, and form two
or three layers of extremely dense end-])le.\uses in the substan-
tia gelatinosa. ivamon y Cajal states that numy of these col-
laterals, e.specially those arising from the dorsal ])art of the
tractus .spinalis, end in well-defined "cell islaiuls " in the dorsal
part of the substantia gelatinosa (Fig. :54(i).
The work of Hregnum,* in wliich the degenerations follow-
ing section of tlu^ main l)ranches of the trigeminus were
studied, nuikes it seem certain that in the rabbit the fibres
from the nervus ophthalmicus run in the vcTitral part of the
tractus spinalis ncrvi trigemini, whiK' those from the nervus
maxillaris and from the nervus numdibularis run in the donsal
part of the tract. For important data regarding the functions
of the tractus spinalis nervi trigemini, the ca.se studied clinically
by llun f and pathologically by Ira van (lieson is referred to.
* Bregma n, V.. rdxT t'xiicriinciilt'lli' aul'stoii^eiiilc Ucj^t'iKM'ution niDtor-
ischer and .sciisiblor llinuierven. Arli. a. d. Inst. f. Aiiat. ii. Physiol, d.
t'lMitraliKTvoiisyst. an li. Wicii. Univ.. Lcipz. u. Wicn (IH'.Ci), S. 7:i-!)7.
f Iltm, II. .Vnalj;L'sia, 'I'lierniit- Ana'sthosia, and Ataxia resulting from
Foci of Softening in the Medulla Oblongata and ("erebellum, due to Occlusion
ofthelioft Inferior I'ostcricir ('erel)ollar .\rtcry. A Study of the Course of
Sensory and Co-ordinating Tracts in the Medulla Oi)longata. N. V. M. J.,
vol. Ixv (1807), pp. 513-519.
<♦
(jlUOUI'IXd AND CIIAININO TOdKTIIKIl OF NKlUoNKS.
•j:{
Van (JehuchtiMi, in tlic first edition of iiis toxt-booti, dc-
8cril»('(l tliu asccndiu"! liiiilis of tlic lil)r('s as passiiij^ ii[) in tlio
coursi' of tlu! dcscciidiii}^ nicsciiccijhaiic motor root as far as
tiic inferior colliculi of tlu^ corjiora (iiiadriyciniiia to tlio lateral
n';j;i()ii of the {?ray matter of the a(|ue(hiet. The studies of
Lii,i,'aro,* von Kulliker, and Kanion y C'ajal, however, make it
prohaitle tiiat tiie fil)res of tiie desci'iidinjf mesen('e|)lialie root
are cliielly, if not entirely, motor, and in the second edition of
van (iehuehten's work these eonelusions are agreed with.
Some authors deseribo sensory axones of the nervus tri-
{feminus passinj; directly n|) into the cereljcllum. The demon-
stration of the existence of such libres would not be sur|)risin^^
now that we know that certain of the axones of the dorsal
funiculi and of the nervus vestibuli pass directly into the cere-
bellum without underjfoinj^ relay. Nevertheless, such a direct
cerebellar tract for tlm lu-rvus tri^fcminus has not yet been
proved for human bein<fs,f and its existcn<'e is vijijorousiy op-
posed by von lieehterewj and 'I'urner.* The latter, a, very
careful observer, believes that what has been described as the
"direct cerebellar root " || of the trigeminus corresponds to the
fibres extending; between tlu^ nuclei of the roof and Deiters'
juicleus, and ])robably also to those connecting;; the superior oli-
vary nuclei with the nuclei of the roof. Obersteiner,'- in the
last edition of his text-book, expresses the opinion that those
who deny the direct relation of tln^ nervus trigeminus to the
cerebellum are in the wrojig.
Centri2)etal impulses arriving along the fifth nerve can affect
the motor nuclei in the medulla and upju'r cervical cord either
by means of collaterals from the axones of the peripheral nerves
* Tjiiufaro, E. Siiilc cpllulo (Torij^iiio dollii radiec (liscoiideiitp del trige-
iiiiiio. Arcli. di ottal., Palrnno, vol. ii ( 1 H!)4-'!).")). pji. 11(5-11!).
f vail (icliiiclitfii lias I'ollowi'd in tlio eiiiliryo cliick by Cldlj^i's ini'lliod
trigeminal fibres <liivc'tly into the eerebflliim llimiigli the braeliium
pdiitis.
i von IJecliterew. W. I'ebi'r die Trigcniinuswurzeln. Xeurol. Centndbl.,
Leipz., Hd. vi (1H8T). .S. '2m.
* Turner, W. Aldren. The feiitral Conneetions and Relations of the
Trigeminal. Vagn-glossopliaryiigeal, Vago-accessory. and Hypoglossal Nerves.
J. Aiiat. and I'hysiol.. l.ond.. vol. xxix (IWiM-'O")). pj.. 1-1.").
II Eding(>r's dinete Hi-nKiiriKrhe h'lt'inhiniltdhn.
^ Obersteiner. II. Anieilnng lieiin Sliidiuiii des Hanes diT nerv")sen ("en-
ralorgane. Ill Anil.. Leipzig u. Wieii (IHOO), S. 40:!.
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Corporation
^o
1% my<o ^»?&*X^ "^
/
23 WEST MAIN STREET
WEBSTER, N.Y. 14^80
(716) 872-4503
524
THE NKlJVorS SVSTKM.
tlic'iiist'lvcs, or liy iiiciiiis of rulljitcriils or tcrniiiials of cuutrip-
etal ni'uroiK's of a liigluT order.
It will be soeii thiit the central prolongations of the cell
bodies of none of the })eri])horai sensory neurones collecting im-
pressions from tlie body itself pass to the cerebral cortex directly.
The centripetal impulses, therefore, which enter by means of
these neurones into the nerve centres must be carried to the
L'erel)ral cortex through neurones with which these come in
contact. But before describing these sensory neurones of a
iiiglier order it will be convenient to consider briefly the char-
acters of the peri])heral sensory neurones connecting the organs
of special sense with the central nervous system.
(Bi Centripetal Neurones of the First Order collecting Impressions
of Special Sense (connecting Organs of Special Sense with the
Central Nervous System t.
I'luler tliis headintf tlie gustatory, olfactory, visual, and
auditory peripheral sensory neurones will be discussed.
CHAITKR XX.WI.
c
I'liKll'HKKAL CKXTKirirrAL NKUROXKS COXCKRNKD IN' TIIK
SENSE OF TASTE AXI) SMELL.
I'erii>liend centri{)etal neurones mediating taste impressions — Xcrvas glos-
sopharyngeus — Xervus trigeminus — Nervus iiUermedius — Taste buds
in tongue — Heliitiuii i>f nerve fil)rils to taste bud — Intrageniuud fibres
— Intergcmmai fibres — Specific taste (jualities — rerii)lieral eentripetal
neurones mediating olfac^tory impressions — Perikaryons — Distal hair-
like processes — Noii-medullated axones — Tenuiiialion in olfactory glo-
meruli — Hegio olfiictoria of nasal mucous mcnibnme.
1. Peripheral Gustatory Neurones.
Cnsfafori/ Xciiniitc.'f. — The periplieral sensory neurones
mediating taste impressions cotisist of a portion of those of
the nervus glossopharyngeus and probably also of tlie nervus
trigeminus and nervus intermedins * (Plate I, Fig. "2). In gen-
eral, what has been said regarding the collection by the sensory
neurones of the spinal and cerebral nerves of bodily ini])ression8
holds also for the nerves of taste. The peripheral branches of
the ganglion cells concerned in collecting taste impressions come
ultimately, however, into contact in the mouth and tongue with
ccrtiiin peculiar structures — the so-called taste buds.f
The structure of tlu'sc bodies is well known and has been
accunitely described in the text-books. They are egg-shaped
or barrel-shaped masses of epithelial cells situated mainly in
the vallate papillne and fimbria*, though a few of them are sciit-
* In this conneetion the (taper of A. V. Dixon — <>n the Course of the
Taste Fibres, Edinb. M. .1., n. s., vol. i (IMiiT), \t\>. 'M^i-iOl — may be consulted
with profit.
f These bodies appear to have been discovered independently by lA)ven
and Scliwalbe in 1H67.
r.'ir.
\
I
. t!
I il
;)'.
526
TIIH NKKVOIS SYSTKM.
tored olscwliore over tlio toiiijue, in tlic soft palato, and on tlio
opiglottis. Dissu * lias ivcuntly (k'scribt'd similar structuri's as
Nil
W'il.
v.
Cone.
— Siipporthifi cfll.
yriiritriH'llicltal
,-,'11.
AL, Rod Cfll.
AVccc lihn'l.'i.
Fifi. 347. — Si'liciiiatic rcprcscntatidii of a taste liiid. lAftcr Hrnnanii, Sil/iiiij;sli.
(I. k.-lia,\ cr. Akail. <1. \Vissciis<li. /ii Miiiicluii. 1SM8, as iiKMlilicd by Hdcliin
uiid Villi I)a\ idoir. )
o('('iirrin,<r also in tlu' nasal nuicous inoiiil)ran(\ Tlicy roprosont
u (lilt'crontiatod portion of tlu> opitlu'lial jwrt of tl.c mucous
membrani'. At least two sorts of cells are present in each
taste bud: (n) the supportinjjf cells consisting of an outer layer
with nuclei centrally placed, and an inner layer of very delicate
cells with nuclei situated at the base ; (/>) the sensory cells, the
so-called neuro-ei)ithelial cells of the taste buds — delicate long-
drawn-out cells which stain well by (iolgi's method, and which
send a hairlike process through the pore at the apex oi the
taste bud to the surface of the mucous meinbi:n;e. It is proba-
ble that the flat cells at the l)ase of the taste bud correspoiul
to a special form of .uipporting cell (Fig. -W). The nerve
fibres, as von Lenhossek f and Uetzius J have shown, end free in
* Dissp, J. Ucbor Epilliollinosiicii in dcr I{('y:i() olfacloriii der Siiuger.
Ntu'hr. V. (1. k. Gescllsch. d. Wissonscli.. (Jottiiij,'. (1H!)4). S. 6(5-71.
t voii Ii('nhi)Si=;('k, ]\I. Dor feinero I5aii mid (bo XorvonoiKb'guiifjcu ilor
Ciosohmacksknospon. Aiml. Anz.. .loiia, lid. viii (lH!»'i-'9:?), S. 121-127.
I Kotzius, (J. Dio \i'i'voiioiidijjiiiijj:oii in dem Uoschinneksurfjfau dor
Siiiiijctioro mid Aniphibioii. IJiul. rntorsuoli., Stockliolin, n. F., 15d. iv
(1S!)3), S. l!)-;{3.
I'i.
I
UllOUPlNG AND ("llAlNlNd TOOKTIIEK OF NHIUOXHS. ^liT
iiiiioiig tlu! cells of tho tiistc hud. Tlu' old idcii that the iiciiro-
cpitiudiiil (iolls <;tivc off iixis-cylindcM' procosses which ran to the
nerve centres has been detinitely disproved.
It is to be reiiiemhered that the nineous nieinhranc of the
toTi^ue is supplied in j^t-neral with nerve endinjjfs niediatinjj the
sensations of touch, pain, and teniperature just as is onlinary
skin. In addition it receives the nerve fibres uhich })ass directly
to the taste buds. The nerve fibres approaching,' the taste buds
and beconiinif coiuu'cted with them (intra<reinnial fibres of von
Leidiossek) are distin<,Musliable from the bnuiches which termi-
nate amon,!^ the ordinary epithelial cells of the mucous mem-
l)rane between the taste buds (inter<jenimal fibres). From two
to five fibres a])proach the base of each taste bud, each of which
on entering the bud breaks up into a fine end-arborization, the
\
Suht/emnial cell
InUrgemnial fibrils
Fi(i. ;VJS. — Taste buds (wilyculi siistatorii ) and pcripln'ml pstrcmities of pc-
riplu nil pioccsscs (if pcriiihcnil Kustatnry neurones, prepared hy (iolfti's
method from the papilla fidiata of llie raMiit. (After M. von Leiiliossek,
Anat. An/.. .letia. lid. viii. lS!i:{. S. ViW. V\\i. 1.) «. iinpretiliated taste eidls
and a single snpportin>r cell; lielow the ta^te b. id a snlpijemmal cell is in-
dicated ; /(, the bejtiiiniiifis of the nerve librils iijton and between the taste
buds.
individual fibres formin<( a complicated plexus about the con-
stituent cells of the organ, though without entering into any
i;
jiM
r>-2^
'I'lIK NKUVors SVSTKM.
rcliitioii otlitT tliiiii tliiit of contiict with iinyct'll iind jippiU'ontly
witlioiil tlic I'oniiiitioii of aiiiistoinosori iuii()ii<i: I lie individual
fibrils, it is stilted tliiit t'lc iiitcr^cniinul liljfcs arise ri-oiii spe-
cial nerve lihres aixl lu'ver from tihre.s wliieli j,Mve oil' the iiiti-a-
,);e?nmal nerve tilaniejits, a statement of very great physiological
importance if conlirnu'd ( i''ig. ;US).
- iT"
Fki. :?(!•. — Scln'miitic roprcst'iitatiDii of tlic iirriplu'ial and ccntnil coinluclidn
li:illi> (•(iimcitccl witii llir (irKiOKin j;ti>liis. I Alter \V. vein Hi'ditcrcw, I>it'
lifitimysliMlnun im (itliini uiid Itii( kniiiuuiv ; Dciitscli vuii K. \V4'iiil)crj;.
Zwtilc Ailll., \y\\y/... 1S!I!I. S. 1st. Via. l.ll. 1 j/x. Klaiidiilii siiliiii:ixilliiiis ; iil.
lu'iviis liiifjiiiilis ; jic. iiapillir vallatu' ; I', ncrviis tri;;<'iiiiiuis ; 17/. iutvus
iiiti'i'incdius ft facialis ; /.V. iicrviis KJossopliaiyiiKctis ; I",, .N. oplitlialiiiiciis ;
r,,, N. inaxillaiis ; 1',,,. N. ii'aiidiliidaris ; jm, jics anst'i-itius ; :iii. N. aiiricu-
laris ; fsl. fdraiiun styioiiiastdidi'mii ; flit, clionla tyiiipaiii ; /i/>.v, N. pftmsiis
siipci'licialis major; (/.v/i. K^mfjlii'ii spliciio-palatiiiiiiii ; ;/ 1', wi'itrlion sciiii-
liiiiaic tlassci'i ; r.oil. corpus callosimi ; ./'<;, coiKliictioti patii for tasti' to tlic
ccrcliral cortex; /;;■•.■, corpora i|iiadrif;eiiiiiui ; iil, nucleus ieiitiforniis ; lli,
tlialanius.
Concerning tlie existence of several typos of taste buds of
specific structure I'orresponding to specific taste qnaliHes, we
have as yet no data, nor are we informed at all concerning any
special nuclei of termination of the taste fibres in the medulla
and pons separate from the other uerve tibres of the three sen-
sory nerves involved.
imf^A
I
GIlOUPINd AND CIIAIN'ING TOOKTIIHll OF NKUKONKS. 52'.t
A j^t'iuTiil scheine of tlu! tusti' coiKluctioii paths has ht'cii
prc'pari'd by W. v. Hechtorew. It is reproduced in Fig. '.UU.
2. Peripheral Olfactory Neurones.
^rhe olfac^tory neurones of tlie tirst onh'r extend from llie
miu'ous meinbrano of the iu)se to the olfactory l)ull). Tlie cell
bodies of these neunnies are, reniarkal)le to state, situated
aetually in the mucous nuMubrane of tlie nose itself, thus dif-
I'erinjx from all other ju'riplieral si'iisory nein'ones (in human
beings).* It had long been known that in the olfactory region
FiCf. 'MSO. — Schcinc of tlic <'imrs(' fdllowcd liy iii rvc iiniml
;i|i|iiH';iliis 1)1' iii;uiiiii:il.s. (AftfiS. Uaiiii'iii y ( njal, i-cs i
Tniiisl. Iiy A/.ouhiy, I'aris, IS<M, p. lOit, I'"if;. ^ti.') .1. olli
hninc ; />'. (illhitury j^'Ihiik riiliis in luill)!!. oUhctDritis
tnictus (ilfiictdriiis ; A,', (lU'aclury " ;;nmiil(s" : /•', adjan
f.', n'Kiiiii iifsliia oHactdria lateralis; /, tullalcnils of the
ii'lls ill till' oll'acliiry liiill) : //. cdllatrnils ol' tlicsc same ;
(illiirtiiiiiis : /,, eeiitril'ii^jal lilue leriiiiiialiiif; in the Im
(iiilfji cell of 'I'ype II (ir (leiidraxDne. riic arrows .sliow
impulses.
ses III
lonvell
iictoiy
; ('. Ill
•lit pyr
axoiies
ixoiies
llais ol
tliedi
the uU\
es it lee-
miiniiis
ilia I <i
ainiilal
iol'lhi
ill the t
faetorill
rcetioii
utory
S etr].
meiii-
11 ; I>.
eells;
mitral
lactiis
is; .V,
of the
of the nasiil mucous membrane cells of two kinds exist — su])poit-
ing eells iind sensoi-y ei)itheliiil cells, the latter being delicate
narrow ct^lls provided with hairlike processes which project
slightly upon the mucous surface. Max Schultze,f in ISli'-*, dis-
* It will tints bo seen tliat in the iisisiil iiitieotis inoiiilii'aiio of liiiintiii be-
iiifjs we iiicot willi a sensory apiiai'atiis iiiorpholofrjcally very .similar to that
wiiieh has tieeti deserilx'd in tlie epithelial siirfaee of the fish worm.
f Scluiltze. M. Ueberdie I'',iiilimiii<;s\veise(ler(iertt('lisiierv(Mi ttnd der Epi-
tlu'lialgeliildo der Xasonsclileiiiihaiil. I5er. d. K. I'retiss. Akad. d. Wissnnscli.
zti Berlin (IH.IG), .S. ,'(()4-r)14. — riilersticlitinpMi tiebcr den liaii der Nasen-
schleinihiiiit. namentlich die Struct it riinil Kiidif^tiiifjsweisiulertiertiehsnerven
lieiin Meiisclien nnd den \Virl)eltiereii. Abliandl. il. Niitiirf. (iesellsoli. /,ti
llalle, Kd. vii (IHG'^). — Das i'',pitlieliuni iler IJieehsidileimhatil des Meiiselien.
Centralbl. f. d. mod. Wissensch., IJerl., I'.d. ii (I«04), S. 1585-390.
1
il
\'
t:
H
■T'
i \
i f
r)8<»
TIIK NHKVOUS SYSTEM.
covered that from the proxiiniil end of each olfactory cell an
olfactory nerve fil)rc took its orijrin. The use of the inethylene-
blue inetliod by Khrlich * and Arnstein f and tf tiol«;i's nietliod
by Kainon y Ciijal ;]; and van Cehuchten * has proved beyond
Kid. 351. — \ Kldiiicruliis (ilfai'tdi-ius from ii youiif; cat : iiictluKl of (icilf;!. ( .Vftir
.\. von Kollikcr, MuikIImicIi (Iit (icwclii'lflirc dcs .Mfiisclicn, lid. ii. lA'ii)z..
IH'iti, S. 7(11. Kifj. 7r)4i. F<i, liia oH'ai'toria lircakiiiK up into terminal liraiiclifs
iiisi<l<' tiu' Klonicruliis ; re. caijillary lilootl-vcsscls.
* EhrlicJi, P. Op. cif.
t Arnstein. Die Methylenblaufilrbunj? ills histologische Mcthode. Anat.
Anz.. Jena, Bd. ii (1887), S. 125-185.
X [{ainon y C'ajal, S. Oripen y tcrminacion de las fibras ncrviosas olfa-
torias. Oae. san. de Barcel. (1890).
* van (iehuchton. A. Contribution a lY'tmle de la muqueuse olfactive
chez les niaiiunifrTes. C'ellulf, Lierre et Louvuin (1891).
*tl!
(JUorFMNO AND CllAININd TOdKTIIKIJ oF NKl'IioNKS. :,;n
doubt that tlu' olfactory iicrvi' fibres really ri'i)ri'S('nt tiic axoncs
of the eell bodies situated in th<' nasal inueous ineiubraiie. The
short hairlike jirocesses of these cells rejiresent the dendrites
(Fij,'. :5A(>).
The nerve tihres whicii end free in the inueous inenibraiu' of
the nose indei)endent of olfactory epithelial cells probably be-
long to the nervus trip'niiiius, and have nothinjr directly to do
witii the carryiiiir of olfactory impulses.
!i!!!t
?, H
1
Fio. 352. — Area of iiasil iiiucims inciiilifiiiic wliicli. aiTiirdiuj; to tlic rcst-arclics of
V((ii Hniiiii, is iimrrvalcd liy Nii. oll'actdrii.
The axones of the olfactory neurones are uoJi-iueduUated.
They pass throuffh the cribriform plate of the ethmoid bone in
bundles (Xn. olfactorii) to the olfactory bulb which they enter.*
Here they terminate, as (Jol^i first proved, by free end-arboriza-
tions in the so-called olfactory fjlomeruli, comin<r into maiufold
contact inside them Avitli the large dendrites of the mitral cells
* For interesting? data concerning accurate measurements in the doeiain
of the lmll)us and tractns olfactorius, tlie reader is referred to tiie article liy
II. 11. Donaldson anil T. L. IJollon, The Si/e of Several Cranial Nerves in
Man as Indicated by the Areas of their Cross Sections. Am. J. Psychol.,
Worcester, vol. iv (18<)l-'<»2). pp. 224-229.
111.
\
r^ii'j
TIIK NKUVOUS SYSTKM.
'f (
of tho olfactory hiilh which arc iiltiniatcly distributed in these
structures. The ciitral ccdls and brush cells <»f the (tU'actory
bulb represent olfactory lu'un/tu's of the second order and will
be des(U'ibed 8ul)se(|uently. 'IMie endiiifjs of tiie Nn. olfactorii
are well shown in Ki^. :{')1. 'i'he dendrites of the mitral cells
are not imprej^nated. The exact area of nasal mucous nu-m-
braiu' concerned in the sense of smell is much smaller than
many have believed. Thus, the studies of the late von Mrunii *
liave shown that the olfactory region is limiti'd to a relatively
small part of the superior turbinated bone and the udjac-ent
region of the nasid septum. The area in each nostril situated
at the very top prol)ably doe^' not exceed in extent nu)re than
two aiul a half sijuare centimetres. Von lirunii in the course
of his careful measurements found in one case that the olfac-
tory epithelium extended in the right nasal cavity over a sur-
face of t>,")7 stpuire millimetres. In a se(U)n(l case the distribu-
tion amounte(l to "i'-iS millimetres (Fig. 35'^).
* von Hrunii, A. Rcilni^^e zur iniki'uskoiiisclit'ii Aiialoinie der iiioiiscli-
licheii Xasenlinlile. Aivli. f. iiiikr. Anal., licmii, IM. xxxix (IH!)-,'), S. (J;{2-
(551.
,
•ill
1 i
T-pB
'■.U
3. Peripheral Visual Neurones,
niAPTKU XXXVII.
TIIK PKKIPHKUAL VISL'.VL N i:r ItON i:S AM) TIIK STKrcnKK Ol
TlIK KKTINA.
Oilier studies of tiic rctimi — Its liimeilatioii — Studies of 'I'urtuferi, Ramon y
("ajal, and l)o;;ii'l — (loli,'i prfparatioiis — 'I'lie rod ceils and cone eclis —
Tliu l)ipoiar celis — Tiie f,'aiif;iion celis and optic nerve tilires — Superini-
position and inlerreiiitions of tlie retinal elements — IMiilier's littres—
The amacrini; cells — The horizontal cells — ( 'omparison of the periph(>nil
visual neurones with other peripheral centripetal neurones — Von Len-
hossek's study of the cephalopod eye — IJeduction of elements in the
visual conduction i>ath.
Vixval Neurones. — The peripheral sensory neurones con-
cerned in the sense of sight are situated in tlie retitia. Tlic
older ideas of the structure of the retina which most of us were
taiij,dit in the nu'dical schools were extremely complex, and tlu'
memorization of the exact ])osition and appearance of the vari-
ous layers of this memhrane was hy no means easy, since the
intraretinal rehitions and connections of the elements were en-
tirely ohscure.
It will he recalled that externally next to (1) the layer of
hexagonal pigment cells were situated {'i) the layer of rods and
cones. Then followed, ])assing inward, {'■]) the outer nuclear
layer; (4) the outer molecular layer; (r>) the inner nuclear
layer; (d) the inner molecular layer; (i) the layer of nerve
cells, ami, lastly, (S) on the inner surface of the retina, the layer
of nerve fibres. These various layers were easy to make out in
preparations stained M'ith ordinary nuclear dyes (Fig. '.in'.]), hut
as to wiiat the individual layers meant, and to exactly what cells
the various nuclei aiul ])rocesses belonged, there was much dis-
agreement.
Instead of this unintelligible classification based simply upon
staining iippearances and without any rational interpretation as
regards the internal connection of the elements, the newer studies
533
li!
1 1
fH
.-!»"
. (i
< I
r)34
TIIK NKIJVOl S SYSTKM.
(»f Tiirtiiffii,* Hiimoii y ('ajiil,f Doj^'icKJ mi'l <'tli('rH liiivc tini<,'ht
us what tlicsf v!iri(His layers tiicaii. IT (»nc will conifjarc l-'i;;. :}'»;{
with the silvcr-pictiirc of the retina ( Kij:. :jr)4), the eiKirtiioiis
Kiinplifieatioii wiiich liiis resulted from the application of (IoI^m's
method to the study of this iuend)raiie will he immediately ap-
parent. The silver ehromate method shows that in the retina,
in addition to certain more complex relations wliieh exist, three
very distinct si'ts of cells are superim])osed : (1) 'I'he (U'lls to
wiiich the rods and cones belonjf ; {'i) the l)ipolar cells; (;{) tlie
<.fan<rlion cells of the retina.** Comparing,' the old classification
with the present simple scheme, it will be seen that the outer
* 'riii'tiifi'i-i, F. Siiiriiimtoiniiidella ri'tiiia. Airli. porle .seined., Torino,
vol. xi (IHHT), pp. ;{;ir)-;i."iH ; and ill .he Internal. Moiiiilsclir. f. ,\iiat. ii. I'iiy-
siiil., lii'ip/-., H(l. iv (IMST). .S. 4'il-44I,— Sulla isiologia della ri'lina. Ann. lU
oltal.. Pavia, vol. xvi (1HH7-"8H), pp. 4~4-47(».
f ivaiiion y Ciijal. S. Kst met lira ilc la ri'lina dc las avps. Rev. triincst.
liislol. noriii., I'tf., Madrid. No.s, I y v, Mayo, IHMl-l. — Siir la niorpli<>loj,'ic el Ics
I'oiuiexions des I'lt'nu'iils dc la ri'liiie des oiseaiix. Anal. .\nz., .leiia, Md. iv
(18f<!>), S. 111-131. — IV'(|Uc'nas contriljiicioncs al conininiicnlo del sislciiia
ncrvioso. III. La retina de los liatrauios y rejitiles, Aj,'oslo (^IN'Jl). — Nolas
prcveiitivas sobre la retina y gran siinpatiiM) de los nuunifcros. Marcclona
I)ic., ISIM. — La ret ina de Ids Telosteos y aleunas oltservaeiones .soltre la de los
vertel)rados siipcriores, Madrid, 1S!I2. — HI nuevo eoneepto de la liistologia do
los ccntros nervioso.s. Uev. de cieii. ined. de Hareel., vol. xviii (1HI)2), p|).
;{f!l-l{76; 457-4Tr>, etc. — La rcline <les verteluvs. ('clinic. Lierre et Loiivain,
t. ix (1H!(4), ])p. 131-:i40. — Xeue Darstclluiig voni liistologisclieii Man des
Centralnervensy.steins. Arch. f. Anat. u. Physiol.. .\nut. .Mitli., Leipz. (1H1);{),
S. .'$1!>-4'JS. — I)ic Retina der Wirlicltliiere. I'lilcrsiicluingen mil dor (Jolgi-
Cajarsclien Cliroiiisilhcrnictliodc and der Klirlicli'sclieii .Metliylenlilaiirilrb-
uiig. In Verbindung niit dem Verfnsser zusainmcngestcllt, uebersetzt, und
niit Liiileitiing verselicn von R. (treef, Wiesbaden (1804).
X Dogiel, A. S. I'eber das Verlialten der nervt'isen Klcinento in der Re-
tina der (lanoiden, Rejitilien, Vogil, uml Saugethiere. Anat. Anz., .Jena,
Hd. iii (1M8S), .S. KiH-U;?.— Uebci die nervosen Eleiiiente in der Netzliaut der
Ainpliibien und Viigcl. Iliid., IJd. iii (1888), S. ;{42-;{47. — L'eber die iicrvc'iscn
Eieniente in der Retina des Men.sclien. Areli. f. inikr. Anat., Honn, lid.
xxxviii, S. ;517-Ii44. — l'eber die nerviisen Elemente in der Retina des
Menselien. Arch. 1'. niikr. Anat., Roiin, lid. xl (18i):2), S. :21»-;58.— Zur l-'rage
neber den Ban der Nervenzellen und ueber das Verliiiltniss ihres Achsoncyl-
inder-(Xerven)-F(irtsatzes zu den Proto|)Iasinafortsatzcn (Deiidriteii). Arch,
f. inikr. Anat., Bonn, Bd. xli (18!»;i), .S. G',>-87.— Neuroglia der Retina des
iMensehen. Arch. f. inikr. Anat., Bonn, Bd. xli (1893), S. G13-G2!5.— Znr Frage
ueber das Verlialten der Nervenzellen zu einandcr. .Areli. f. Anat. u. Phy-
siol., Anat. Abth., licipz. (I8!»;{). S. 4',"J-484.
* For one ganglion cell there are about one hundred rod and cone cells.
■
(}U()UlMN(i AN1> CIIAININ*; TOOKTIIKU OF NKIUONKS. y.\rt
midciir liiyor corresponds to tlic luiclt'i of the ('('lis whose distal
processes represent tlie rods iind cones, while the inner nuch'iir
layer corresponds to the nuclei of the hipohir cells. The outer
molecular layer represents the reijion of contact or concrescence
relation between the proximal processes of the rod and cone
cells and the distal processes of the bipolar cells, while the in-
ner molecular layer corresponds to the region in which the ter-
mi
K
I
r)3«?
THE i^ERVOUS SYSTEM.
minals of the proximal processes of the bipolar cells enter into
contact or concrescence relation with the dendrites of the
ganglion cells of the so-called " layer of nerve cells." The layer
of nerve fibres represents the axones arising from the cell bodies
2.)
r) :
I'l;
I've
; ''■
lie)
Hill
Fio. 354. — Sflicmt' of tlu' stnictiirc of tlio ri'tinu. (AfU-rS. liiimoii y Ciijiil,
Ketiiiii (lor Wirbcltliifrc, rclxTsct/. v. (irccrt", Wicsli.. WM, S. 17, Fif;.
-1. layer of rods and cones ; //, bodies of visnal cells (external nuclear layc
C. external plexiforin layer ; /•', layer of l)iiMdar cells (internal nu<learlay(
F. internal plexiforni layer; (I, layer of t;an>;lion cells: //, layer of ne
fibres: ((. rods; /(, cones; c. bipolar (rod) cells: /. bipolar (cone) cells
lower brani'liin;; of bipolar ( rod i cells ; /'i, lower brandling of bipolar (co
cidls; (j.li.i.h, KaiiKlion cells brancliinj; in ditferent layei's of tlie inte
I)le xi form zone ; .r, contact between tbe rods and tlie bii)olar ( rod ) cellt^
contact between the cones and tlie bipolar (cone) cells; t, Miiller's cells
centrifuftal nerve fibre.
in the " layer of nerve cells." These axones pass over the inner
surface of the retina to reach the blind spot of the eye where
they penetrate through the whole retina iind make up the con-
Btituent fib''es of the optic nerve. The nerve fibres of the optic
nerve undergo partitil decussiition with those of the opposite
side in the optic chiasm, and pass through tlie optic tracts to
terminate in the corpora quadrigemina, lateral gtmiculate bodies,
and pulvinar of the two sides ( Fig. ;?5f)).
These three sets of elements — the r ^ and cone cells, the
bipolar cells, and the ganglion cells — represent the principal
GROUPINU AND tIlAIN'IN(J TOGETHRR OP NKURONKS. 587
morphological constituents of the retina. There arc, however,
certain otlier cU'monts present in tliis nienihraiic wliich must
he mentioned, though tiieir rehitions to tiie principal elements,
whil'^ they have been carefully studied, are not yet satisfac^torily
understood. These are (1) the so-(!alled Midler's fibres (spongio-
lilasts of His), whieli correspond to the ependyinal framework
of the spinal cord and brain ; {'i) the so-called amacrine * cells
of Ramon y Cajal (also sometimes called spongioblasts), which
occur in the inner molecular layer, aiul which appear to be
G.c.a.
_ Kasal port.««t
* "^"^'^"'^ ■ Ckiasma opticiim
1. f ^«-
Ped.cer.
^-■'".rr,.
"n.
•«««.
\ ^- — I Pulvinar of
^ * ^ Thalamus
Cgtnjit
C.t.
C.i.
N.lrochlttriK
TtiiipBf«l p»'l«n
Fio, 355.— Sclu'iiu' iif visual (•(induction iintli. Lettering same as for Plate II,
ri«. I.
anaxones; and (3) the horizontal cells, outer and inner, of the
outer molecular layer.
a privative, fianpos long, and iws fibre.
liiii?
\
t
i\
m
,53S
THE np:iivol's systplm.
Fig. ;!.")().— Ki)itlu'liiil cells (Miillcr's (ilircs) of tlic rctiim. (After S. Hiiinnii y
Ciljal. Die Retina der Wirheltliiere, relirrsetz. v. (Jreelf. \Vi<>sl)., 1M<>4. Till',
vi, Fifjs. I iiiid 'J. ) A. Miiller's tiUns fi-diii tlie ri'tina of the fro^ : (/, extci-
mil iiiicleiii' layer: /i, external plexiforni layer: c. internal nnelcar layer:
(/, layer of spon^iolilasts ; c. internal plexiforin layir; f. layer of fjaiiKlion
eells; ;;, hasti layi'f or uieinlirana liniitans interna. B, Miiller's tibris or
oi)itiieiial eells from the retina of Cypriinis earpio.
ifijill
Fio. 357.— A section tliroimli the retina of an adult do};. i After S. Kanion y
Ca.jal. Die Retina <ler Wirlicltliiere. rdiersetz. v. (ireelV. Wiesh.. isill, Taf. v,
Fia. •,>.) ((. cone tihre : h. ^jraniile an<l lihre of a r<id : c. liipolar C4>11 witii
ascendiiif; eiid-hrnsh lieloiifiinf; to the rods; i\ liipolar cill with end Iniish
s|)read out tiatbe loiurintr to the cones; /. ttiniil l'il>olar cell with('nd-l)rnsli
spread cint Hat ; /(, dilfiise ainacrine cell, the varicose hranclies of which lie
for tlie most part directly iii)on the Kanj;lion cells; /', ascendin^' nerve lilires;
.;'. centrifnjial tlhres : </ and ;/'. s))eciiil cells which are very rarely imiMCf.'-
nated ; ii, jraimlioii cell which receives the end-l>nish of a liipolarcdl (hstiiied
for the rods: ih, nerve lihre which hccomes lost in the inti'rnal idexiforiu
layer; }>, nerve lihre of the oi)tie-lil)re layer.
.
'
rrIlOUl'lN'(} AXl) CIIAIXING TOGETIIKIl OP NKUKONES. 531)
The shape of Miiller's fibres is shown iji the accompanyinji;
figure (Fig. :{")(;). It, is not improbable that they represent sup-
])()rting eells.
Tlie anaxones (aniacrine cells) represent, in al' probability,
mechanisms for correlating the activities of the different neu-
rones (bipolar cells and ganglion cells) with which they come
into relation in the iimer molecular layer. Since it is exactly
Fill. 358. — Xcrvc cells (if the rctiiui of the ox. stained with nietliyleiii' hhie ;
iiietlKiil (if Khrlieh-Dofiiel. (After S. RniiK'ni yCiiJiil, Die Kediia der Wir-
lielthiere. reliersetz. v. (ireelf. W'iesli.. ISitl, Tiif. vii, Imk. !(. I This liKiire
slidws tlie extertiiil (ir siiiiill iKirizoiital cells, n. cell IkkIv eoiitaiiiinj; vev.v
intense lilne .pdts ; h, very line and innch-bran(died dendrites; c, ax(ines
witliiiiit visiltie collatenils ; (/. sinjile axis cylinders wliiidi (iften liraiicli and
which iir(>l)iil)ly arise from the lar^e or internal horizontal cells.
in their neigh])orhood in the retinti thtit the few centrifugal
fibres of the optic nerve terminate, it is not impossible that the
influence exerted by the cerel)ral centres upon the retinal activi-
ties is mediiiti'd by these cells (Fig. ;}o7).
3G
t
J
m
1
540
TIIK NKIi vol's SYSTKM.
'I'lic liorizoiital cells of the outer nioloculiir layer can be
divided into two ^M-otips — an external ^n-oiip {ccUtdc KKpcrJicidli
(li ijrnitdvzza media of Taitufcri) .iiid an internal set (lar^'^o
superficial cells of 'I'artufori, largo and small stellate cells of
Dojriel).
The external hiriznntal cells are very numerous, and have
loiifi^ diverging,' dendrites, whicdi spread out to form a thick
plexus (Kig. .'558). Their axoiies are extremely delicate and
diflicult to find, but are described by Ramon y ("ajal as coming
off usually from a dendrite. The axones and collaterals are
distributed in the superficial portion of the outer molecular
layer.
The inner horizontal cells (Fig. ,35i)) are of two sorts: (a)
Those with descending dendrites, and {b) those without de-
Fuj. ;!")!». — A pcrix'tiiliciilar section tliroiijjii tlic ictiim of the nx. i.M'tcr S.
KaiiKMi y ( ■;i.jiii. Die Kctiini ilir Wirlicltliii re, I'dx rsctz. v. (irtcll', Wicst)., ISitl,
Tilf. vi, I''ij;. 1~. ) n, internal li<iii/iinliil ceil with descenilin;; pidcess ; /),
aucitlier cell of llie same sort witliont desceniliiij; in'ocess ; c, initral-sliapecl
aniacrine cell with two hr.inclies which jio in opposite directions; (/. lar^c
iunacrine cell for the fourth suli-layer ; c, small KanKlion cell which hranches
in the second suh-layer ; (. t\. Ii. i.j. dilferent types of neurojilia cells; k, in-
terstitial aniacrine cell which hranches chiefly in two suh-layers.
scending dendrites. The axones of tlie cells with descending
dendrites are very thick tind long and devoid of collaterals.
According to Dogiel, these axones descetid in order to enter the
hiyer of optic nerve filiivs, a view denied by Ramon y Cajal,
M'ho finds tluit th(\v are distributed to the externtil molecuhir
hiyer itself. Tlie axones of the inner horizontal cells without
descending dendrites are also thick and run liorizontally for a
considernble distance. It seems ])ro])able that the function of
the horizontal cells of both sets (outer and inner) is to bring
t: !
(JilOUIMX(} AND ('IIAIN'IN(; TOOETIIHll (»F NKURONKS. ,-,41
into ri'liition (Icliiiiti! j^n-oups (>♦' rotls with other (U'liuitc {^fniijw
\yiu^ at 11 distiiiicc.
The question ut once arises, Wliich of the elements mentioned
are to be h)oke(l upon as the jieripheral visual neuromas analo-
gous to tht? j)eri})heral sj)inal centr'petal lu'urones and to tiio
peripheral olfactory neurones!-' Tiiis (juestion is not so easily
deeided, and is nuide more complicated by the fact that the
whole retina arises embryologically {rii/e Section IV) from the
central nerve tube, and iu)t from a separa*^e basis, as do the
spinal and cerel)ral ffaiif^lia. I i)n'fer, though i.iiis opinion may
not be sluired by all, to look ui)on the bipolar cells of the retiiui
as the analogues of the spinal ganglion cells; their distal j)ro-
cesses are then comparable to the afferent libres in the ])eriph-
eral spinal nerves, and their proximal ])i<)cesses to the axones of
the tibres of tlu^ dorsal roots. The rods and cones would then
correspond to dilTerentiated epithelial ejtendymal cells* with
which the peripheral processes of the bipolar cells come in con-
tact, just as the so-called neuro-epithelial cells of the taste buds
in the tongue stand in contact relation to the ])erii)heral fibres
of the glossopharyngeal and other cerebral nerves, or as the
TitstzoUcn of Merkel are related to the peripheral processes of
spinal-ganglion cells. The axones of the bipolar cells would
find their "nuclei of termination " in the outer molecular layer
and in the ganglion cell layi'r of the retina; the latter would l)e
analogous then to the gray matter of the s])imil cord and me-
dulla (of the general spinal sensory paths), to tln^ nucleus ahe
cinereie and nucleus tractus solitarii (of the gustatory con-
duction path), and to the olfactory bulb (of the olfactory sen-
sory conduction path). This would make the ganglion cell
layer of the retina, the ojjtic nerves, and the optic tracts parts
of the central nervous system. 'I'Ik^ o])tic nerve is then, in a
sense, not a peripheral nerve. Inasmuch, therefore, as we are
here considering only the sensory lU'urones of the iirst ord(T,
the oj)tic lu'rve and its conrsi' and termination will ])e tlescribed
when the sensory neurones of higher orders are considered.
It is only fair in conclusion to state that the recent studies of
* This view is all the more enticiiif? in tiiat recent stiiiiies tend to show
that the outer limbs of tlie rods and clones represent structures formed of
(lie cilia of the ependyiiial cells coiled up and ;,diic(l toj;cthcr. Cf. Krause,
W. Uelicrsicht der Keiuitnisse voui Hau der Ketiua ini Jahre 1H'J5.
Schmidt's Jahrb., lieip/., Hd. ccxiix (iy!)()). S. 90; 201.
Vi
1
I
Ml*
TIIH NKKVOl S SV.STKiM.
L
/
r,hs.
IiikIii.i III ic
Kll/ l'<7/».
4
(!l{(»I'IMN<i AMI (IIAIMNd T<>(iI-yniKU -tF NKUIIONKS. r.lM
■
i
M. vuii liCiiliossrk ^ iiKik" il cxtrciiirly |H'(iliiililr tli;it tlir rnil
iiimI i'uik' cells ill some iiiiiniiils :ii'<' n'iilly true |M'ri|ilicnil visiinl
iiciiroiK's ( l'"i^'. )!<•<»). It" litis lie true, tlicii llic I ipdliir cflls of
llic rcliii.'i niust. in siu'li iiiiiiiiiiis In- rc^rjn-dcil ns visiiiil sensory
lUMintiicH of the Kceoml order. Tliere is no ohjeet ion, ho I'lir as
I know, to conHidcrin^f I lie rod cells nnd cone cells of llie rel inn
of luiniiin Ix'inf^s ms iirlinil nvunnics. No iinido^^ons cell is, liow-
ever, existenir in llie oll'iictory tnncons inendmme.
In nninmiiils two kindsof \)\\)iAuv ci']]^ (iir/n'/rtifi/i/ spr(i/,iii(/,
o|»l!<' nenrones of t lie lirst onler) occur: (I) liipoliir cells for llie
rods, willi verticiil end-tufts, wliicli enter into condiielion rela-
tion with llie terminal s|tlieriiles of t lie rod cells, and ('.') hi|Milar
cells for the cones, the dendrites of which form end-tufts, which
lie ilia deeper |ilane than those for the rods; these end-tnfts
enter into eondiK'l ion relation with the terminal hiil^nn^^s and
lilirillu) of the cone <'ells. 'The hipolar cells nearly always conio
into conduction relation with several of the roil cells, or of the
cone cells. The niimlier, however, varies; whih' one bipolar
cell may stand in relation to only a few, atiother may he in a
position Id receive impulses from a j^'reat many. In the fovea
centralis, where the niimher of cone cells is enormous, the indi-
vidual c<»nes are very delicate, and the hasal swelling,' of each
cone comes into contact ex<lusively with the dendritif^ liift of
a single hipolar cell.
* v(i(i riOiiliossi'k, ,M. Histolofjisclii' Uiilcrsn<'liim{,'('ii imis ScIi1m|i|)cii dir
('('|)lialo|i(MlcM. Arch. f. inil<r. Aniit., I'm. mi, IJd. xlvii (IHIMI). S. 15 I 'JO.
I''l(i. :!(»». Sclii'iiiiltii' rcpn'si'iilMtiiiii nf tin' stnirdnr iif llii- nliiin iiiiil visiiMJ
liilii' (iT I'.lcddiic. (Al'tcr M. villi l.cTiliiissrk. Airli. I'. iiiiUr, Aiiilt., niiiiii, ltd.
xlvii, |H!i(l. TmC. viii.; In tiic rcliiiii (Hily ii I'lw visiiiil nils lO'r rcincscntid.
Siirli H (I'll ciinsisls hI'm disdil |iniliiiii.';il iini, tlii' " nid ii|i|i;iiiitiis," iiiid iiC tlic
ili'tiiMl iiiicliiili'd iidl liiidy. Tlu' liitlcr ^i vis iitl', nt liiist in soinc iiiscs, ;it its
Imsal cxdiiiiily smni' slmrt |iiii(ii|iliisnHr lllnils. Isviiy < ill is loiiliniKnis
with il niTvc tilii'i', wliirli piissrs ms ii "nliiiiil liliir " iiilcr lirrl'imitini; the
r!irlilnt;iniins srii r:i In llif visuid lobe. In thi' liilti r it itids in tlii' ri(.'ion nt'
(lie plcxit'orni l:iy<'r, piiitly in its cxlrrnid pli'xus willi ii diliciilr lilirilliiry
Mi'liiiri/Mtiiin. pMi'lly tliniii^li m ilrscrndin;; lininrli mi llir rxlriiiiii limit nl'
III)' inti'innl liiiri/nutMl pirxiis. In tlir I'Xicniiil ;;i'iinidr layer tliirr air
llirrc vaiii'tii's iif <(dls : Tlii' siipi rliiial laii;c cills, J (<( I ; Ilir laii;rr rxtrinal
uraniili's, .'(/»); and llw sinallcr cxtiTiial granules, J>c). In the plcxirniiii
layer, the ant neli I Ik muMs ilenients only, llie ^lia eel Is, ..' ((H, are represented.
Of the eleiiieiils nt' llie inlernal t;raiiiilar layer (.'>,.';,.';), the cells 7 (»■) cnr-
respdiid til the sinaller, the eell .'. if) In the larjier variety iif internjil
t;raiiiile cells, 'riieir a xinics K" dn" n iiiln the inednllaled siihstance to end
(herewith free rainilicaliiiiis ( hypnthetiean. In the niednllary layer the
cells arc lit' the nrdinary type il!,i:,i;) that is, cells with desceiiiliiii; axoiies,
(if which (here are sinaller. li (ip, and larger, '/'/i l. examples. The cells,
.{(/', represent the rarer t'lnin nainel.v. the cells with ascendini; axmies;
linally. at the hiittnm, is slmwii a very laru'c ^iaiit cell, /' (i), which sends it.s
axiine, as dn iniist nf the cells in the medullary la.vi'r, into I ' pediimde.
:. f!
< iiAi"i'i;ir \\ WIN,
TiiK iM:i{ii'iii:iiAi. Ai niioia mi hums am. tiii. simiim,
(tUtiA N i»l' ( oitTI.
Tl.o iirrviis .•urhlo.r (Jiin«lj.,n s|.in>lo-Tl. ..•Iil,.nr rn„( ..f (|,.. «,.,.„>.li,.
n.-no IVriphonil pnicossos mi.l ll... ,.ipm of (',.r(iC..|,tial M\n,i,.s-.
NM.l.-i,.fi..,„.inMli,.i, Hilniv„li,.nnf,iv„„,.s--T.Minn.M|.Mn.lcnll,il.-n,ls.
4. The Pnriphflral Auditory Neurones.
Till iM-ripli.'nil n.Mirniirs ..f il,,. :ni.lilurv put lis ;iiv tli„s..
wliirh .-m.T int.. tlu' l'oiin;iii..ii of Hi,- m.lix ,M..'li|,.iiris N.
to-
fr A?
Via :?(!1, Til.- l;il>.viintliii> iii.'tiil.niiiM.riis oC tli.' lifjlit iiil.iiinl v.n- u( :i Ininnn
.iiil.v.vonl 111.' lirHi in..iilli. M'.'ti (Vo-.n llw m.'.linl -i.l.v ( Mi.iMi K'rtzius 'is
sliulilly ino.litir.l l.y A. K'mii1..t. 1 / i, iil li. iiliis ; .', ivic^siis ill li.iili ' ' ;
iiiM.ul:! M.uMi.M iiiii.iili : ;, sinus pcsiciior : .>. sinus Mi|.rii,.i' <: Miiiiitilli
in.nil>r;inM..'ii sni..'ri.n- ; .'. miiii.iiIIm ni.'inl.r.iiiil.c;i l;il.'riilis ; .v, :iin|inll:i niciii
l>i:iii:ucn nosicnor: ;*. .lii.tiis s.'iiiiciiviilHiis siip.Tlnr ; /(*, .in.ins siniirir
.nlMiis iiost.'iii.r : //. .liirtiis scnii.in iilniis hil.'nilis ; /,'. wiil.'n.'i! niniiili „f
.Ills siini.l.N ol llir 1:ii,t:i1 s.nii.iiviii;ii- .iin;!! .iponinn inlollic iiiiicnlns • / ;
siK.iilMs : /;. ni;i.iil;i .-i.nsli.M smnili ; /.I. .lii.'liis .-ii.lnlviii|.li.ili<iis •' iii
. u.nis iiln.'iil,.sii.riilMns; /;. .lii.liis r.Mini.'iis . is. .■UTiiiii v.'s|il,iil;,lv ..i'
(lll.tns .•o.lil.-Mvls: /.''. .111. Ins cKJilrMlis ;,'(*, N. 1,1, iiilis; '/ >; \ .|,iisli,i|s
£>/. N. \.>slil.nli; .','. \. s'l.ciilnris ; .'.>', \. !ini).nll.iiis iniriior ; '; N ,.,„.||.'
li-iv; -'•>. .lislnliiiiKiii 111 \. .oihlrn. wiihin tin- l.iniina spiriilis ossca
.■.44
i.
/I)
(JIJiMMMNO ANIi CIIAININO TOOKTIIKU <>l' NKHUONKS. f. ITi
iiciiHliii, nr Hd-nilli'tl riiTviiw cmiIiIcii' * ( l''i^'. ^I'll). 'Ihc i<||
Ixidii'M tin* Hitii:it*>i| in tlx' ^'iiii^liini s|iinil)' (kiiii;^'Iii)|i oI' ('(uli)
wliic'li licH ill I lie liniiy cnclilcii f (I'iK- 'K'*). 'I'licscf (('liH rciiiiiiii
?v
/
l''lii. :t(l;.'. — Hrctiiiii llii'Mii)>li Mir <'iii'lilrnr iTj^iiin kC tlic liiliyriiilliim ossciis el iiii'in-
liiiiiiiicciis hI'm (initMii pi^. lACIiiA. A. I'ihIuh iiinl M. vnn Ikividud', l,ctir-
lillrli ijcr IIM.ildHi.' (Irs M.iimIhti, (•(<■.. Wiisli.. |H!I.-,, S :!(;:.', I'i«, 'J|;(. ) /,
sciilii \ ("^1 iliiili ; III, hiliiiiiii \ is( ilniliirc nl' llif liiiilms ; ». siiliiis spinilis ; n,
iiii'iliilliili'il |H'ii|ilii'i':il lilnrs Miisiiit! I'lcnii iills in tli>' uiiiiMlinii siiirnlc iiiiil
lii'iiit; (ji'^liiiiiiliil 111 III!' iiit;:iiiiiii spinili- (I'lpilii); /«. pi riU;ii-.vipii-i in llif
CiliiKliiiii spiiiilc ; 7, liliiml vissci ; 11, liiiiic ; //, iiiiiiiliiiiii!! vcsliliiiliiris ( IJiisH-
Mcii ) ; l><\ (I ml IIS (Mrlih^iiis ; il. ( iiiii's iiiiiiilniiiic ; I', piiiiiiiiiiiil ill spirnlis ;
li, limiiiiiiiliiiii spiiiilr nirliliir ; /. Iiiiiiiici liMsiliilis; /.■, sriil;! I.Vliipiilli.
* 'riii'iT is nil |iiiHir Hull ill lii^ilicr luiiimils the tii'iirniii's <if thi' ricrviis
vcsliliiili nvv ciiiiceriiril wilh iiii|nils('s which hiivc to ihi with the pcrcciitiiiii
"if siiiiml.
1 Sahi. li. (Siir rnri^iiiH' ilii ncif (i('uiisli(|iic. Arch, iliil. ilc liini., 'I'lirin,
1. xvi (IH!) I '!)'.>), pp. l!>(i-207), liclifvcs, in (iKn-emciit. with Oniifruwicz, that
':^!'*
: i
;-'f
';i
\'
1
r)4(!
•ri!i': NKKvors svstkm.
I)i|)()lar {riilf sii/ini) t lirou-^lioiit life ( l-'iir. :;();!). 'I'lic pcripli-
(■ml processes run out to end free without iiiiiiiifold hraiicliiii"-
111 iunoiiir the epitheliiil I'ells of the spinil or;riiii of Corti (Ifet-
Fli;. 3()3. — Two liipolar cells I'riini tlic fiaiiKlioii si>inilt' (■dclilciu r»f ii youiiK mimsp.
Meth(«l of (iolfji. (After M. voii Leiiliossek. Aiiiit. Hefte. Wiesl)., I{(1. iii[
H. ix. 181W, Taf. xiii, Fig. 1.) /'./•'., i)(ri])lural process; C.K, central axoiie!
zius,* Villi (iehueliteii t) inside the dticttis eocliloii' J (Fig. 'M'A).
Tlio niediilhited central prolongations or axones of these cells
massed together make the iiervus eochlea? (posterior lateral or
many of tlic cell bodies of the peripheral auditory neurones are situated in
the ventral cochlear nucleus, but this view has not been supported by sub-
sequent invest iijafors.
* Het/ius. (J. Die Endifjungsweise des Gehiirnerven. Hiol. Tntersuch.,
Stockholm, n. F.. Rd. iii (1892), S. 2!)-3G.
•f van (iciuichten, A. fontribution a I'ctude des ganjrlions ccrcbro-
spiniiux. CeUule, Licrrc et Louvaiii. t. vili (181(2), p. 226.
X The nervus sacoidi with peripheral distribution in the macula acustica
sacculi is a branch of the nervus cochlea'.
GUOUl'INU AND CHAINING TOdKTHKIf oP NKUHONKS. 547
cochk'ur root of the norvus acuaticuH). They pass into the con-
tral nervous system at the jiuiction of tlic nicdulla with the
pons, and enter into rehition with definite masses (mainly the
nucleus N. coeidea' veiitralis, and ti\e nnch'us N. eoehhse d(tr-
aalis, nueleus tuherculi acustici) of jrray mattiT in which are
situated tho cell bodies and dendrites of large numbers of sen-
sory neuroiu's of the second order.
Tiu' cneidear nerve as it enters the rh()mbencephah>n passes
dorsulward ..nd spinalward lateral from the corpus restirormo
into the medial side of the large nucleus ni-rvi cochlea' veii-
tralis, in which a large number of its fibres terminate (Fig.
305). A buiulle of considerable size, however, can be followed
in Weigert-I'al preparations as far as the nucleus nervi cochlciu
Fia. 3(i-t. — Siiinil DrRiin of Corti of tlic ductus (•(iclilcaris in transvi'vsc or nulial
section. ( Af'tcrd. Kctziiis, from A. Hauhcr's tcxt-liook. ISitS, S. HIS, !•'!«. 743. )
»•(', inciluUatcd distill i)roccs.s('s of liipolar nerve cells in (;anf;lion spir.ile ;
/, fonmien iiervosiini in laliiiini I.viniiaui<'uni tiiviuK passifje to a bundle of
the cocidear nerve lihres; Ih, tynipanid coveriiiK of lamina basilaris; r.s-, vas
spinile; is, internal snpportinj; cells which on the left side ar<' continuous
with the eiiithelium of the sulcus spiralis; /*, internal pillar with an inner
})asiil cell (/;) next to it : //. external pillar with its external hasal cell, '/ ; /,
k!, -i, Dciters" supportinj; Cfdis with i)lialani;eal processes arrivinj; at the sur-
face of Corti's orf;au, there attached to tlu" lannna reticularis, /■ ; //, Hensen's
sii|)]iortinK cells whi(di dinduish in height toward the ri(;ht side of the
figure and art' continuoii.^ with ('. the cells of ('lau<lius ; A, epithelial cells of
the so-called " la.ver of firauules"; /, internal hair cell, the upper end of
which is hidden liy the "head" of the internal i>illar; i' . hairs of iuternat
hair cell ; c, t-xtcrnal hair cell ; c'. c', c', hairs of three external hair cells;
H, )i^ to II*, various cross sections of the spiral cord of nerve distrihutioii ; tlw
"tuniu'l cord" extends from »' to »' as a radial hundle ; I, tunnel space; iV,
Nuefs .si)ace.
dorsalis, where the fibres appear to be continuous with the med-
ullated fibres in the meditil portion of this nucleus (Fig. ^('tCt,
right side of figure). It is probable that the majority of the
I
I-
I i
i ■
i '■ i
^ 1 J
''I
; ^,M
54M
TIIK N'KK Vol's SYSTEM.
Idii
()1{()1'I'IN(} AN'I) (•|IAININ(» TO(}KTIIKl{ <»I' NKllJONKS. .-,4i>
fll)r('.s of this l)Uii(llt' tcriniiiiitc here, tlinii^^li soiiic of tlicin niiiy
puss (lin'ctly tliroiij^'li the dorsal cochlciir luu'lciis to ciiitT tlio
striiB iMiMlulliin'S (sivc u('Ustic«'),or, piissinjj over the dorsal bor-
der of the corpus rcstiforiiu', pluiif^c down to tlii' region of
tlic homolateral superior olivary complex and lateral lemniscus
(Held). Tiiu position of the areas currespuniling to the vou-
Ncnvm
I I
11
Nu.01.
Nuoam.
Flii. Utiti. — Tniiisvi'isc scctidii of iiii'iliilla ((lili)iiKiit!i iind ci rclicllimi oC iicwliidii
fliild. (Stiii's ii, scclidii N'o. lUi.i ''.c, nirpiis rc?.tir(iniic (llic iKiit iiicdiil-
liltcil corri'spciiids in llic iiimjii Io tlic diicct ccrflH'lliir ti'iirt): /■'./.. Imiidlr
(•ciiitimiiiiis with till- f'liniculiis liili rails ul' tlnccird: /■'./. »i.. lasciciiliis ImiKi-
tiidinalis uii'dialis: .V./.V. A'.. N. fil'issDidiaryiiKciis ct vakils : S.XII., N. Iiypn-
fllossiis; .\ii.i(.. iiiicli'Us dfiitatus : Sii.u.c.il., iiiiclciis N. cciclilca' diirsalis
siiKwn iiiKrc t,v|(i<'ail,v on c>|i|nisiti' side cif tit;iiiT ; .\ii.ii.r.iii.. imclciis N. vt's-
tilmii iiicdialis; Xii.n.ii.il.. iiiiclciis olivaris at'tcssiirius doi'salis: Sii.o.ii.m.,
lilit'li'iis olivaris acccssoriiis iiicdialis: .\)i.ii.i.. iiikIciis ulivaiis inrcrioi-;
yii.t.s., iiiiclfiis tniitiis solitaiii ; /'../'., iM'diiiiciiliis lldcciili : /'// pyraiiiis;
li.il.ii.ri-st., radix di'scciidciis N. visilmli: .s7./,/., stnitiiiii iiitcnilivan' Iciii-
iiisci : <!il. iilaiic of l(iii>;itiidiiial section \n. (i(i. [Noti:. — Tliis ti};iirc has
hccn disproportionately reduced in ilie repiddiietioii.]
tral and dorsal cochlear nuclei, tind the relation of tliese to the
enteriuii root bundle, iind to the cor])us trapezoideum. are well
showTi in I'^lorence Siibin's second diii<,n-iim (Ki<j;. MOT). 'IMie two
nrclei, tbouj^h practically continuous with one another, tire
fundamentally different in structure, tind a very little study en-
ables one, even with low powers of the microscope, to diiferen-
m '
I
.550
TIIK NKHVOUS SVSTKM.
ii\
it
GROUPING AND CHAINING TOGETHER OF NEFHONES. 551
tiiite the two nuolei at a glance.* A few of the fibres of the
nervus eochleic, acconling to Hehl,f j;o past tlie ventral nucleus
without terminating in it, to enter tlie corpus trapezoideum
FlocciUita
NucltiM neryi cochU-ae
vimlfalis
Biinrilv to funlruliis lateralis
from nucleuf, r.iber of
opposite siilo.
Sulfst. yelatinosa
(icnn N. facialis
Xiicleiis neryi
„,„ I veslibuU nu-itiiiVis
>~f)i^,^\l\mtuiualion cf
'\\h>' ^I'l'^wiiliiK propriits
.' :''','i'* hentrnlis ct lateratis
— Jl,\,\ll •
Trnctiis spinalis
\<'h \niryi Iriaemini
V",,! I ■"
';.'■: I
'^Trart from DeiUrs"
nurleiis lo funiculus
la I em lis
,,;• X> Stratum interoU\iire
'■i':^ I lemr.iscL
"■'/?/'^"- • ,
' '-■'■' -" J Ruplie
•mleus oliymris iidirior
Pyrumia
ill
f-i
Fio. 3fiH. — Rntrancc i(f X. coclilciv into flic cciiti-.d ncrvims system: pnrtiims fif
the cciitriil auditiii-.v patlis iirt' also sluiwii. WcifitTt piciiaratioii. Iliinian
IVi'tiis, :W (in. loiiK. ( Al'tt'i- H. Held. Arcli. f. Aiiat. u. Plivsiol., Auat. Alitli.,
Li'ipz., 1893, S. 210, Fin. 3. ) Tlu' figure is sonuwliat srlii-niatic.
* The reader is advised here and in connection with other descriptions
to refer frequently to the transverse and lonj^itudinal sections pictured in
Figs. ;50H to 324.
+ Held, H. Die centralen Bahnen des Nervus acusticus bei der Katze.
Arch. f. Anat. u. Physiol.. Anat. Al)lh., L.>ipz. (1801). S. 271-291.— Die cen-
tralc Gehtirleitung. Arch. f. Anat. u. Physiol., Anat. Abth., Leipz. (1893),
S. 201-248.
t
552
THE NERVOUS SYSTEM.
...-^^
^
Ccllniiliii. sii/icrwr %>■<
A. Direct systoni. a'cripLoral auditory
.s<'iisorv neurones, oraiiditi i-v neurone's
"I the 1 order.)
', Niicltus nerv'icochltae dcrsnlis
iNiicUus olivaris superior \ '''"'''"* ^.''""'"'
' - ----... \ siipi'ricr
A' coiliUw
Niirlfiin corporis < i
Inipezciriei Ccrpus Inipczoidnim
Nuclrus neni cachlene vent talis
" Ccr/cr
\ Collicitlus inforli
'■u-r
•\'ii,-lciis li-mnisci
latfrtiiis
Cdlii'iiliis sii/H-riiSr
M. Indirect systems. ( .Vnditory neu-
rones of II order and of iii-lier
ordeix. )
Decnssalio brarhii
conjunclivi . . .
Lemniscus lateralis
Nucleus nen i \ \ n^^ ,,
cccnleae. api.-ialii
\ \
^r^:\^ /- 4-
ccyunctivmn
Siriue iicusticue<
7 corpus Inipcxoiriciim y
JVml.-ii.s ficrri ci'Meac vc'nfni/is
AC cochleae
<.Viic/eus lemnisd
Uiterali.1
.*; 1 ^ ' >~ — /; / l.eirmiscus laK-nilii
T
■iXiuicus olivaris
f^iiperior
Nucleus corporis trapezoidei
Ute H Ueld v'r':, 'T'!'"'. ""I'.,""'"; ■"" l'"' '•""''•=" =""""">• ncu.ones,
Fig r. ) ' '^' "• ^ '■>''*'"'•• -^""<- -^''tl'.. L.'ipz.. 1HU3, ,S.240
,
i
(JUOI'PINO AM) (•IlAININ(i TOCKTHKll OF NKIUONPIS. 553
■^
(Fig. ;)ti8), and so come into relation with the superior olivury
c()nii)lex of the same or of the opposite side. Some root libres
may possil)ly, he thinks, go into the one or the other lateral
lemniscus to terminate first in masses of gray matter situated
even higher up in the cerebrospinal axis ( Fig. IW,)). The studies
of Thomas,* by Marchi's method, also make it seem probable
that root fibres of the cochlear nerve pass without interruption
''■i
Fui. 370. — SnKittal iniirkcdly latcr.il section tliroiiKli tlic rli(iiiil>('iu'('])liiiliin of a
fd'tiil iiKiiisc, to show tile I'titcriiit; N. coclilcic. (Al'tcrS. Kanioii y (iijal,
Hi'itnif; /.uin Studiiiiii dcr Medulla < >liloii>;ata, etc., Hresler, Leipz., ISiMi, S.
7!(, Kij;. ;il.) .1, N. ((xdilea' : 11. N. veslilaili; (', sensory N. triKeniiinis ; />,
coriiiis restit'onne ; 11, asceiidiiiu liiiilis of liil'iircation oC a.\<ines oi' N. cocldeie ;
6, desceiidiiij; lini'is; c, huiidle of descending lindis wliitdi enters into the
tail of the Ventral nucleus and into the uu(deus N. cochlea' (hu'salis; <l, de-
.scendinK lindi of hifurcatecl axones of N. trifieuiinus (tnietus spinalis N.
trifjeuiini) cut tauKentially.
^
mmf
\!
directly into the striae acusticae, corpus trai)ezoideum and lat-
eral lemniscus. A point to be emphasized in connection with
the nervus cochlea* is the iibsence of any evidence for the ptis-
sage of any of its axones directly into the cerebellum. Thus
the neurones of tlie first order as well as those of the second
. I
* Thomas, A. Los tcrminaisons cpiitralcs do la raeiiie labyriiilhiciue.
Compt. rend. Soc. de biol., Par.. 10 s., t. v (1S98). No. (i, p. 18:3.
; ' ''
J
m
h
mfF
•J-h
nr>4
TIIH NM^IHVOUS SYSTEM.
order {ride i/i/i'it) of tlio iiiulitory conduction piitli arc in
ni:iri<cd contnist with those of the ncrvus vcstibuli as rcards
their behavior toward the cerebell im.*
: i
FlO. 371. — Mode of tiTiniiiation of the axoncs of tlic N. cocliltu' in tlii' imclcus
N. cnchlfii' vciitriilis of a newborn cat. (.Xftcr S. Kainon v Cajal. Hcitran
ziini Studiiini dcr Mtdnlla Olilon^ata, ftc, Uifslcr. I,ti|./...' \m\. S. 77, Via.
2()a.) (/, lil)rf cndiiiK in a conical liiill) : li. fibre surroiindinf; a cell: c. 1lii-ce
end bulbs coniinf; into e.intaci witli a sinf;le cell ; (/, stellate end bulb ; c. deli-
cate collater.ils from a libre connected with an end bnll); f. end bulb with a
hole in it.
The axones of the cochlear nerve bifurcate on enterin<r the
ventral nucleus, dividinjj, as do the dorsal root fibres in the spiiuil
cord, into tin ascending and a descendin<j limb, each of which
gives otf many collaterals (Fig. ;?70).
The ascending linil) is short, and, passing dorstihvard and
nackward, ends tis a rule in the ventral cochk'iir nucleus. The
descending limb is much longer. It runs posteriorly and enters
the tail of the posterior i)art of the ventrtd nucleus and in many
instiuices pa^-ses into the nucleus nervi cochlea' dorsalis.
The terminals and collaterals f rom the a.vones of the cochlear
* It should 1)0 nieiitioiioil. limvevcr, tiiiit some invest iijators, juiumg' tliom
Foster and Sherrington (I'lirt III of Foster's Text-book of Physiolojxy) and
von K<"»lliker, maintain lliat t)ie cotjlilear nerve is, by way of the stria' acus-
tiiii' and corpus restiforine, eonneoted with the corebulliim.
is
OllOUPING AN'I) CIIAININO TOOKTlIKll OF XKriJONKS. ;,;,:,
nervo form curious iMid-arhorizutious wliicli conu' into close con-
tact with the cells of the nuclei terrniniiles. They wore first de-
scribi'd hy IFcld, and have also hecn pictured by Uanioii y Cajal.
They are well illustrated in the acconi|ianyin<,' li<j;ure, which
shows the terminals in the new-horn cat (I'iii'. :{TI).
The course followed hy the auditory iini)idscs inside the cen-
tral lU'rvous system (auditory neurones (»f the second and of
higher orders) will he considen^d in a suhsenucnt chapter.
M
87
SUBSECTION II.
m
i ^
Neurones "Within the Central Nervous System Con-
necting the End Stations (Nuclei Terminales) of the
Axones of the Peripheral Centripetal Neurones
with other Portions of the Central Nervous Sys-
tem (Centripetal Neurones of the Second Order and
of Higher Orders ; Central Neurones of the Sen-
sory Conduction Paths).
CIIAITKR XXXIX.
('i;n rmi'KTAi, Ni:ri{()Ni:s insidk tiik cknthal nkhvous
SYSTKM.
riiissiCicatiiiii — Thiisc conccriu'il in lioilily scnsatioiis — Those iicrtiiinintr to
lilt' s|)iii!il i)i'fi|ili('r;tl ct'iit ripclal iii'in'oiit's — (inmps ol' tlicsi' — 'I'liosc llio
cell bodies of wiiieii are silnaled in liie nuclei ol' I lie I'liiiieuliis trnieilis
and I'liiiieiilus ciiiieatus of each side — l''ilira' arcuata' iiilenia' — Stratuiii
iiili>roiivai'e leninisci — l)eciissai io leiiiuiscoriim — Ijeiniiiscii^ niedialis —
XiK'leo-cereliellar systems.
IIavinm; considcird tlic iiciiroiu's colU'c'tiiiij inijnilscs from
all parts of tlic Ixxly (iiicliuliiic^ the orpins of sj)i'('ial sense) and
earryiiiij: tliein into the nerve centres, it is necessary to exam-
ine briefly the main facts which have been ascertained concern-
inii the neurones which are so (lis])osed that they can take np
the impulses, where they are left by the ])eri])heral lU'urcmes,
and carry them further. In this examination we shall follow
the same i>lan as that adopted in our study of the peri])heral
centripetal lu'urones and consider (.\) the ])aths concerned in
the carryiiifi of bodily ijiipulses sejiarately froui (R) those \vhose
function it is to forward the impressions derived from the
organs of special sense.
" 556 —
(ilioriMNO AND CIlAININd 'nxiKTIlKK' (iF N'Kl'KONKS. 557
(A) Central Neurones of Sensory Conduction Paths other than
those corresponding to the Organs of Special Sense.
Ill coiisidcriii;,' the jxTiplicriil spiiuil iiciiroiics we liavc seen
over liow vast u territory the colliitci-als and Icrininals arc dis-
li'iltiihMl ill tiic spinal vim\ and iiicclidla. It is obvious that
iMipiiiscs arrivini,' aloii^f a sinj^dc peripheral spinal neurone can
alTeet neurones of the second order hy means of eolhiterals and
terininiils in very dilTercnt portions of the; }i;niy matter of the
lit
U.li
m
V\r,. H72. — T'lodi- of fnnrtli vciilritU' iiiid diirsul view of iiiyclfiicciiliiilini. (Al'tcr
.1. Ilcnic, llaiKlliiii'li (Icr Ncrvciilclirc dcs Mciisclicii 1 1. And., IJrMiiiiscliwciK,
IMTit, Via. \'S.\. S. 2i»i. ) Tlic icrcliclliiiii iiiid vcliiin iiicdnlliirc anlciiiis liiivc
Ih'cii cut lliroll^li ill till' niiildlc line and turned t(i the side. .Ic. ahi' ciiu rcic ;
,((•'. acci'ssory iiiK'lciis (iC StilliiiK ; fV, clava ; fV/, (•iir|M)i';i (|iiadi-iKtiiiiiia ; /•',
lliicciiliis; /'V, luniciiliis (iiiitatiis ; /•'(;, fiiiiiiuliis gracilis ; Fivi, fovea siipcrinr;
/.(•. loeiis I'ieriileiis ; Oh. ()\>v\ : /'o, poiilieiilns (of taenia veiilrieiili i|iiarti)
laid to OIK' side ; '/'»(', iiiicleiis iiervi eoeiilea' dorsiilis and stria- inedilllares ;
]'iiiii, veliini iiiedlillare aiileiiiis ; tlie ■■ indicates tiie collicnliis facialis.
\
spinal cord tind mednllu. An inimens(> problem here lies before
us. At present we can not speak with desired definiteness coii-
eerninji: all the neurones of the serond order and of liiffber
orders here concerned, but have to be content with describing
the relations of certain jireat groups of neurones of the nuclei
terminales as far as they have been made out. The lower motor
neurones situated in the ventral horns are, as has been seen,
558
TllK NKKVOL'S SYSTEM.
thrown uikIit tlic inlhiciu'c of colhitcrals and torniiiiiils of pe-
riplicral sensory ncin'oiics, hut in such an event tin- impulses
can he carried, it is helieved, to the nuiseles alone; the jtro^n'oss
g—
Fi(i. :573. — Triiiisv('rs<' st'ctimi at the .jniictioii of llic mcdiillii spinalis witli the
iiicdiilla iililoiijiata. (Al'tcr.!. IIi'iilc. llaiKUiiicli dcr Nfrvi'iilclirc dcs Mcn-
sclii'ii. /wciti' Anil., I'.iaiiusc liwfifi. ISTil. S. Jiis, l'"i;:. \)i\.i Cr. canalis cfii-
tralis: Ti/f/, (•(iliiiiiiia - fjrisca i din'salis : ri/r, cipliimna (firisca ) vcntralis ; /•>,
t'miiciilus vciitialis: /■<•, t'asciciiliis rimcatiis ; /•'(/. fascif'uliis >;i'ac'''s; f(. sub-
stantia ;,'fialiiicisa Rulandi ; ;;c, sniistantia K'latiuosa ci iitralis : /. ».iitral riHit
of the tii'st cfiviral nerve; llie ■ indicates a eniss secticin of a Idipiid-vessel ;
/■v. t'orniatio retienlaris. This section is helnw the level of the decnss;itio
))yraniidnni.
of centripettil impulses toward higlior centres would not be fur-
thered. The neurones concerned in the latter function consist
of iit least several well-marked irrouiis. It will he convenient to
consider (1) the central neurones pertaininjf to the spinal sen-
sory nerves more or less sepanitely from {'i) those which per-
tain to the cerebral nerves.
1. Central Neurones, the Perikaryons and Dendrites of which are Situated in
the Nuclei Terminates of the Axones of the Spinal Peripheral Centripetal
Neurones.
Tite neurones, the cell bodies iind dendrites of which cor-
respond to the nuclei terniinales of the dorsal rotits of the
(iK()L'IMN(} AND CIIAIMNii nxiKTllKIl OK NM-U'liONKS.
r^m^t
sjiiiiiil ncrvs may
bo
COllSK
U'lvd
uiidcr tlu! rollowiii'T liciul-
Ill-'S
(ii) Nt'iiroiu's tilt' cell l)()(li('s of wliicli iiro situiited in tlu' nu-
cleus funiculi <^fnicilis and nuclciis funiculi cunfiiti of each
side.
(//) Neurones ihecell bodies of wliieliure situated in the nu-
cleus dorsal is of each side.
{r) Neurones tliecell bodiesof which are situated in the f^niy
matter ol the cord, tlieir axones iii'l))ing to form the fasciculud
ventro-lateralis ((lowersi) of each sidi".
('/) N"
th
[(I) .\eurones tne cell hodies in wtueh are situated m tne
gray matter of the cord, their axones making up the I'aseicu-
ii ;»
111-
m
bal
Fi(i. :?7t. — 'rraiisvcrsc section tlirinii,'li tlic incdiilla (ilildnsriitii at tlic level of tlio
ileeilssatii) |pyraiiii<limi. i \fler .1. Ilciile. Ilandhiiili der Ncrvciililire des
Meiisclien, Zweile Ailll.. Hiamisriiweij:. 1S7!», S. :>1 1, Kij,'. \)H\.) Ciir. eiiliiiiiiia
(Ki'isea ) veiitrali> or veiUral horn; /•'('. coiitiimation in tlie iiiedulla ol' the
t'ascieulus vi'ntralis propriiis ( I'ln-ilrr-ilnniiiri'st of flic (ierniaiis) : /•'/'.'/. t'ascie-
uli cerel)ros|)inales pyraniidales iindcrKoint; decussation : ;/, sulistantia fida-
tiiiosa Kolandi ; A;/, spinal extremity ol' nucleus luiiiculi KHicilis ; A7, ncrvus
accessor! us.
'J-l
'If
lie
lus proprius (ground bundle) of the ventral, lateral, and dorsal
funiculi of each side of the cord.
^n
ifio
TIIK NKI{ vol's SYSTKM.
Wliilc tlicst' represent the cliief nuclei teriiiiimleM of the
(lorHul roots of tlie spiiiiil nerves, it must Ite jioiiited out that a
certain nunilter ol' dursiil root lihres terininiite tirst in tlie cere-
Fl<i. lit.').— TruTisvcrsc scclimi tliiciiiKli tlic iiiciliillii ciUlmi^iiitii at tlie livil ot' llie
iiiiisl cmikImI lil;i niiliriihiiiii <i\' llic iiciviis li.v|)i);rl(issiis. ( Alter .1. lli'iilf,
ll;iii(llpiirli <1( r Ncivcnli'lii-f dis Mciiscliiii. /wcitc Aiitl., ISriiuiiscliwiii;. ISTlt.
I llif iiiciliilla 111' the iMsciciiliis vcli-
S. •_'!:{. Fii;. I'-J". ) /•> . niiiliniialinii ii
tnili^ prdpriiis 111' llic siiiiial ccpid ; /■'/<//, pyniiiii^ lat iii>|ii tiikisI
ciissatiii iiN raniiilmii ' ; (/ '
( liiirdaclii
>l' ill
listaiitia Ki'iatiiiDsa ; A'c, iiiicli'iis I'lmiriili rmn'ati
): A'k. iiiuii'iis riiiiii'iili },'iarilis (iipjli'. 'I'lir (licussalin liiiiiiis-
tlii- lijilirc. tliiiii),'li it is to lii' sciii at tliis level. (.'(.
iiiiiiiii IS iiiil milieatcil ii
Fit,'. :}?s.
bellum, iiiid possibly also in the formtttio reticularis griseu of
the medulla oblonfjata (rii/r infi'n).
{(((hi) The nuclei of the dorsal funiculi (nucleus funiculi
frracilis and nucleus fiinicidi cmieati of each side) are situateil
in the medidla oblonjrata tit its junction with the s])iu;il cord.
The swellin.trs on the dorsal surface of the medulla, known on
Ciich side as the c/kcu and tlie iKhcrriihdii cKid'o/tdu, are due
to these nuclei (Fiii :{T".'). The (■/(/('(( corresjwnds to the /ii'-
ch'iis fiddcKli (jraciJis tind the fii/'crrxiKiii riiii('((tinn to the
(JU<)riMN(J AND CHAINING TOOKTIIKU OK N'Kl'WONKS. :,»',|
nidlnis (iniinili rminili. A study of u sfrics ot" scctioiis
( l"'i<,'H. :{'"{ to :iTi) tliroujrli till' iipptT portiDii of the cervical
jKii't (>r tlii> 8])iii!il cord iiiid tlic lower |)ort ion of t he iiumIuHu
rcvcids tlie ireiienil rcliitioii (d' the lihres (d' tiie (h)rsiil riiiiiculi
U
ill
['■■ki. :{7(i. — 'rriiiisvcrsc scctiini of tlic iiicdilllii (ihlon^atil nt the level iit' (lie CMudiil
cxlri'iiiily 111' till' nucleus iiliv;ii'is iulerim-; pdliisli pi-eiKinilidU. ( Al'lef .1.
ilelile. Ihiudliucli di rNelveulciiredes Meiisi lu^ii, Zweile Aull.. IJiMUlisc liweii;,
ls?!t. S. :.':iO. I'i;;. \'-\\.) Cc. e;in;ilis eeulralis; FIxi. tiluie iUcuMlie externie
v<Milniles; /'V. iiiuaiusiil' ventral fuuiculus of the spinal enrd ; /'c, I'aseieulus
eiinealus ( jiurdaelii ) ; /•';/. I'aseieulus uraeilis (Ocilli ) ; I)))/. I'aseieuli eerelini-
spinales pyianiidales almve Ihe lexcl of the deeussalii) pyiatnidniM ; .\ii.
nuclei anuali : A//, nucleus ueivi liypnjjlcissi ; A'o. nucleus nlivaris inferior;
A'/>. mulens (ilivaiisaceessurius nicdialis ; I', raphe; '/'..s./i. I'., I lactus spinalis
nervi triKcniini ; A'//', radix neivi liypciylossi ; ■,<n(ss seelinn ol' ldi>i)d-ves-
xel ; ■■ ■, liiiifiitudinal seclicm ol' blood-vessel; t, tract us solilai'ius.
( ^UJ
lie
to these nuclei. Passinj; from helow upward, one intikes out
tliat its the masses of f^ray mtitter Ix'giii to tippetir, the volume
r»«i2
TlIK NKIIVOI'S SYSTKM.
ul" till' f.isiiciili (»!' wliili' lihrc'S Itc^jiiis to (liiiiiiiisli. In seel ions
Htill hi^'licr up the micli'i uru liirgiT anil tho fiiscimili grow pro-
Ngl Vv
Fl(i. 377. — Tniusvcrsc section <il'tli(' incdiiUii (ililoiii;Mlii Mt tlic level (irtlie middle
of tlie iiueleiis iiiiviiris iiil'eiiiir. (Alter .1. Ileiile. Iliiinlluieli der Nerveii-
lelire (les Meiisclieii, /weite Aiilt., liniiiiiseli weij;. Is7!l. S. •':>-. V\ii. V.V.t. ) (',-.,
ciiriiiis reslilnniie : /•'/','/. liiseiciilj pyniniidales ; A';;/, nucleus ( tenniiiiilis)
nervi Kliiss(p|)liiir.vu^ei ; A'//, nucleus ( miuiliisi neivi hypojildssi ; Xii. nucleus
oliviiris inferior: Xnn, inudeus oliviiris aecessoiiiis dorsiilis; Sp, nucleus
olivaris Me<'essorius inedialis; A'r. nucleus alie ciuercie (nucleus terniinalis
nervi va^i ' : /'". ponticulus (of ta'uia ventricull (|uarlil; A*, raplu ; /A',
radix nervi Klossopliarynjrei ; XII. radix nervi hypoKl<issi ; t, traclussolitarius.
j];resisivt'ly sniiillor, until in the ujipermost regions of the nuclei
there are scarcely any white fibres intervening between the gray
(JlJoriMNd AN'It CIIAIMNC TfMiKTIl KU <»F N'Kl'mtN'KS. ;,([:j
imisscs ainl tln' dorsal surface, tlif white liltres having' (li.sa|>-
pearetl l>y niniiin;,' into the imcU>i to teniiinate in them. Tho
rnieh'iis fmiiiuli ^^nicilis appears at a h>wer h'Vel than (h)es Iho
!iiicleiis I'iMiiciili eiineati and it teriiiiiuites at a lower level in
the nieiliilla than does its iieij^hhor ; the white iihres of the fas-
ciculus f,'raeilis have all disappeared at a level a' which there is
still a larije mass of lllires in the fasciculus cuneutus ruiininj^ to
hi''hcr levels.
Nu.com. fg,
l'"|il. :{7S. TliiriNVil-sr Miliiiii tliriiiiyli niiillillil iplil(iii«Mt;i nf licwliiilli cliild lit
level III' (li't'Ussiliii leimiiscipniin. 'Series li. sertiiili Nn. 50.1 I'.r., iniiiills
eelilllllis: Dir.l.. deciixsiil Ik leimiiseiiiillii : F.n.i.. liline iir iiillse iiileniie ;
F.ii.i:, (iline iiri'iiiilie exleiiise; /•'.(•.. rasririiliis iiiiieiiliis l>mil:nlii ; /•'.<■. to
h'.r., Ituiidles rniiii rii>eiiiilus eiiiie:iliis Ici Iciiiiiiilin icliiiiliiil-- ; l\il.i,, laseic-
nlu.s eereliellosliiliiilis ci|- iliieet cerelielliir tiuet ; /•'.;).. lilseieiiliis Kr:irili.>*
(iolli; h'.r.))., I'liseiciilii-, veMlriili> |)i(p|(liMs ; Xii.nini.. niieieiis eipiiiinissiiriilis ;
Xii.J'.v., iilleleiis ruiiii"'li eiilieiili ; .V/i./.i;., iilieleils riiiiieiili Ki'i'ili'- : /'.'/.• pvni-
lui.s ; T.s.ii.W. tnici . spiiiMlis N. trluemiiii: s.ii., siilisiiiiilia yeliiliimsa [lio-
liiiidi']. Wei^eit-I'.il iii(|iaraliciii liy Dr. .Inlin lle\vtt,-.ciii. )
The fibres of the dorsal funiculi of the spinal cord terminat-
injj in the luulci mentioned transfer tho impulses which they
carry to the dendrites and cell bodies of neurones sit uate(l there;
theaxcHiesof these neurones carry the im])iilses farther. .\ large
number of these a.xones appear as internal arcuate fibres which
press in a curved direction to the raphe, decussate with corre-
sponding internal arcuate fibres of tho o))p()site side, forming
the decussatio lemniscorum * (l''ig. -JTS), and then assume a lon-
gitudinal direction in the .so-called interolivary layer of the lem-
niscus {strut II ni inlvnilii'drv li'iiniisci) (Fig. :>7!»). Farther lioad-
* Till' iiatiirc of this (Iccussiition iiiid its relation to thi> nut'lei of tlie dor-
sal funiculi anil to the lemniscus was long niisunderslooil. 'I'lie luyi-liniza-
tion studies of Flecihsij; first threw li},'lil on the .xiiljjeet. 'i'lie (iernians for
a 'oiif^ time spoke of the decussation as the obi'tw /'i/rmnideii/ireiizinitj to
distin^^nii.sh it from the motor deeussaliou or nnterc I'l/ramitlrii/ircnzuut/.
m\
t
I
r
f'
I
564
THE NP]RVOU.S SYSTEM.
Fihrae nminlin'
extern m- ventrii/es
Stratum
' intcrcliviire
lemiiiHci ^
fibnii ari-.int
Nucleus alae
cinereoe
ward this intorolivarv layer is contimious with the Umnisvus
meditdis which runs tlirough the pons and midbrain toward the
higlier centres terminating
mainly in the ventro-lateral
m)u\) of nuclei of the thala-
mus. Another portion of the
axones from the nuclei of the
dorsal funiculi pass through
the corpus restifornie into the
cerebellum.
The nucleus funiculi gra-
cilis on cacli side receives the
termiiuds of the majority of
the axones which make up
(iolFs fasciculus of the same
side of the cord, though it
has lately been shown that a
few terminals and collaterals
cross the miildle line to enter
into the nucleus of the oppo-
site side, forming in tliis way
a terminal decussation of the
axones of the peripheral cen-
tri[)etal neurone system ( Ra-
mon y Cajal's i:nfrecniztinu-
I'lito fcrniiiiiil).* The cell
bodies of the .u'umnc's situ-
ated in the nucleus funiculi
gracilis are triangular or stel-
late, and ricldy })rovided with
dendrites. A part of their
axones pass at first latcral-
ihr/iu rentrale
Funiculus vcntralis
ct lateralis
Fxo. :5"i>.— SclifiiU" (if till" ('oiirsc of Ihc
sciisiiry patlis dI' the doisal fiiuicnli Ward, and tluMl curviug
ill the rcjrioii ol' tlu'ir luiclci in the , , ^• i ^
iiiiMiiiiiii <,i)i,,ii-,itii. After ].. iMiii- iiround become dn-ected ven-
KiT, Ncrviisc (VntrMliPiKiiiic, V. Aull., f i..iliv.n.|l •iiid inedi-dwird hi
Liipz.. isiiti, s. :u:{, Fiji. •..'ij,-,. ) ci.iiwdui aiui numanvaKi ni
order, as fibne arcuati« in-
terna', to cross in the i-aphe tmd to enter into the opposite
stratum interolivare leninisci and thence into the medial part
* Ratnon y Cajal. S. Hi'itrag ?um Studiiini der ;\[etlulla olilotipitH. des
Klt'inhirns und ties Urspruiigs der tJeliiriinerven. Deutscli von Breslur,
Leipz. (189()). S. 51.
i I
Gia)uriN(i Axi) ciiAixixa togetiieu of xeuuones.
>GiJ
of till' Iciimisciis iiu'dialis. Tlic course of tlicso fibres jiiid
their teniiiiialioiis will he descrilx'd ii> fidl further on. A cer-
tain mimhi'r of the axones from this mieleus j)ass dorsahvard
to reach the surface of tlu' tncdulla, and then run laterally as
iihra' arcuata* extci'na' dorsulos to enter the cerehelluni throiijjjh
the corpus restifonne (Kdin<fer, Hruce, Ferrier and 'I'urner).
Further, some of the axones before mentioned as decussatinjj^
at the rai)he instead of runniiii;' longitudinally in the stratum
interolivarc lemnisci, plun<jje veiitrally throiijih or around the
jivranud to reach the lateral surface of the nu'duUa and to enter
the eerchellum throuuh the corpus restiforme. It is lu'lieved
by von Hechterew * that a portion of these librae arcuata' ex-
terme ventrales undergo relay in the nuclei arcuati. At any
rate it apiiears that of the external arcuate fibres having origin
Ml the nucleus funiculi gracilis, the dorsal connect tiiis nucleus
with the cerebellum by means of the corjtus restiforme of the
same side (uncrossed gracilar mudeo-eerebellar neurone system),
the ventral by moans of the corpus restiforme of the opposite
side (crossed gracilar nucleo-cerebdlar neui-oiu' system).
The nucleus funiculi cuneati, or nucleus of Hurdaidi's column
(including the lateral [external] nucleus of Bluini'nauf), receives
the majority of the terminals of the axones of the fasciculus
cuneatus of the same side of the spimd cord, tlu' terminal lii)res
breaking up into very c(unplicatcd braiu-hings in among the
" islands " formed of the cell bodies and dendrites of this nu-
cleus. The ci'U l)odies in this nucleus are also rather small, tri-
angular, or fusiform in shajjc. The majority of the axones of the
cells in the i)ars medialis of the nucleus, like those of the cells
in the nucleus funiculi gracilis, enter the medial lemniscus of
the opposite side by way of the internal arcuate fibres ami the
stratum interolivarc lemnisci. \ considerable luuuber of the
meduUated axones from this nucleus, bowever, again in agree-
nu'ntwitb the nucleus funiculi gracilis, ciiter the cerebellum of
the same (uncrossed cuneate nucleo-cerebellar neuroiu' system)
and of the opposite (crossed cun(>ate nucleo-cerebellar neurone
system) side by way of the libra' arcuata' externa' dorsales et
ventrales aiul the corpora restifornua. The majority of the
* von Hoohtprcw, W. Die Lcitiiiiustnilmi'M im (Jcliirn and Hiiekt'niiisirk.
Lcipz. (lHi)4). S, no.
f IMintii'iiJUi. !<. TohiT (ItMi aousscrcn Kern dcs Ki'ilstnmircs iiii verliiii-
gcrton :\Iark. Nuurol. Cciitrallik. linipz.. M. x (IWIl). S. 2',n)-2:W.
•Hiitf
,1
mv.* '
.
500
TIIH NERVOUS SYSTEM.
Wu.nl
•Hinil
(hi
, 'f -r^
'Ay
c Nu.r.t.v
Dec. Be(ii|L_t9^ 11 ■ . ^W :-f ^ ^
■^ ''''^'■%. ' ■'!'"' m- ^--^''
A'u.c.s.Q)
Jiu.c.S(m)
Hull
L.I.
Hot.Y
Nu.N.Cv.V- Y
Tr.fr. iiu.D>
I. :fl
■ ^^f^ N.Y11
N.Yest.
Ku.n.H
■H.YI.
F.a.i.CCur^l
fl
■Ts.nY
■M.XE.
Fl<;. ;{.S((. Il(pri/iiniiil scclidii lliniiinh llic iiicdiillii, |m
liiii'ii lialii
Wi'i^'cil-ral sliiinin
Lcvfl iif
mil III' iiiicli'iis nliculiiri.-- tcKini'iili. (ScricN
ami iiiiilliniiii iil'a luw-
itiii liniiliii riinjiiiictivi
iii. si'ctiiiii N(
I. Ki.s. ) r
iiiiuniissiira |Mi.stt'i'iiir ciTi'liri ; Ihr.lt.
(li'iMissaliii lirai'liii ninjiiiulivi ;
Ih'c.l'i'chl.. niiiiinissurc liclwicn I>i rliliTcw's niirici : 1>.I.. (ilircs to ilcriissati
Ii'Uiin'iili ; F.ii.i.' Cini.
riiiicali :
/•'.
bnr arciiata' inlcnia' rroni tlif iiuclfiis I'miiriili
riisi'iciiliis ciniiuliis; l\c. ta /•'.)•., liuiidli' Cnnn t'asririiltis
ciinraliis ti> fiiriiiatiii ictiriilaiis : /•'.</., rasriculiis K'':i<'ilis; /•'./.
Iiiii^iliiilinalis iiii'ilialis : /..
Mill.]'., railix niiitnriiis N. Irincinini : .V. 17/., railix N. fai
.V.rc.v/., radi.x N. vrslilaili : .V. 17.. niilix N. aliilm
liypiiKliissi ; A'..\7., railix \. acii'ssurii
Iriiini.'iriis mi'diaiis : /,./., Ii'iiiiiisrii,>< lali rails ;
ialis, |iars scnmda ;
; .V..\7/.. radix N.
•litis
. ///.I (( ), iilirlrils N. iiculiiiiiiitiirii.
pars lalcnilis; A'imi. ///.ift ), iiiiidcus N'. oiMiiimiulurii, parsinipar: .V".
(/i
lllll'll'IIS I
entrails
supciKir. pars inriliali
N. tarialis : Xii.X.r.r..
siiiicriiir,
li:ili
pars latcrali
.\»././., niiflriis li'iiiiiisfi lateralis
Liirlciis N. niililfa' vfiilni
(), nilclriis ri'litralis
Si(.
All.
nilililis crii
trails iurcrior ; .\i(.r.f., inirlciis riticiilaris tc^tmi'iiti ; .Vm./..s., iiiu'lfiis latri-iilis
siipcriiir; N/.i/c.c, stratiiiu Ki'isriiiii riiilialf ; Nck.I'., srnsiiry mnt iiC N.
trij;''iiiimis : .
Di'itcrs' iiiicli'iis til t
siilislaiilia K<'laliiiiisa linlaiidi ; 7V.(V
./>., trait
H'
spmal niri
I: •/'.
(I'rc'paiiitinii liy Dr. .Inliu lliwct.siiii.
.]'., tractiis spinalis N. triKi'iniiii.
tiUULJMXG AM) CHAINING TO(iKi' VR oF NEIRONHS. :,(;7
Su.n.m.
D.t.
J,S-
3
O
^
■5 Ym. each)
Y.V
•F.a.i\Dac.l)
Fig. 381. — Hori/iintal section tliroUKli the nicdiillii. iioiis. and iiiiiltnaiii of iicw-
Ixirii l>iili('. IjI'VcI cit'sti'iitmn iutcrdlivMrc Icnmisci, rorims tiii|i(Zi(i(lrmu and
liiicli'US I'lilicr. WciKcrt-l'al slailiiiin. iSeries iii, scclioii No. Ilili. i TJ., eot-
|iiis traiiezoideimi ; Dcr. Ili-.Cdiij.. deeiissatio liracliii eonjuiiclivi : 1 1. 1., decus-
salio tcf^iiietili Ml lira lis (ventral Iey;nieiilai deeiissalioii oi' Korel i; I'.ii.i.' Ihr.l. ),
filine aiviiahe iiilenne ( deciissalio leimiiseoruiii ) ; /■'./.. lilires coiitiniioiis wilii
Ilie t'lniieiilus laleialis ol' Ilie spinal cord ; /•'./. m.. fascicnliis lonfiilndinalis
inedialis; /•'.(•..!/.. I'ascicnlns I'etrollexus Meynerii ; I, .in.. Icinnisciis niedialis;
A'.///., radix N. oculomotorii : .V..^/(/^^.. motor root of N. Irineniinus ;
i\'.>V'yi. r., sensory root ol' N. Irifieininiis ; .V. 17//. (coc/i. i. radix N. coclilea";
A'. 1 7/ /.I fi'st. ), radix N. veslihuli : .V. 17., radix N. alidnceiitis ; A'. 17/.. radix
N. facialis, pars secunda ; .V..\7/.. radix N. liypoi;lossi : Sii.f.l.iii., nucleus
lasciciili lontriludinalis nieilialis, or nucleus coiuinissune ]iosterioris (nhci-fr
Oriiliiiiiiitiiiiiiskfni of Darkscliewit.si li ) ; Xn.ii.Ill.. nucliiis N. oculoniolorii ;
Xii.o.ii.iii.. nui'leus olivaris accessorius inedialis; .\ii.ii.i.. nucleus olivaris in-
ferior; Xii.d.s.. nucleus olivaris superior; .Vii.tk/kt. nncleiis rnlier; >7././.,
stratum interoli\are lemnisci ;>'.»., substantia ni'jra. i I'repanition liy Dr.
•lolii! Ilewetson. i
™,.!„'i <
'i
■P
568
TIIK NKHVOUS SYSTEM.
Hli
J"-'''
iixoiics from tlio cells in tlio pars lutoralis or Blunienau's mielous
go to the eorc'helltim on the Siinu' side. In tlu' ci-rchclliun
these fibres rim as a compact bundle past the nucleus dentatus,
through the more medial of the two bundles into which the
corpus restiforme here divides (Tschennak), to end mainly in
the cortex of the vermis inferior. On the way collaterals are
given off to the nucleus N. vestibuli lateralis (I)eiters), and to
the cerebellar nuclei, especially to the nuclei fastigii.
As a result of tlie relative positions of the o nuclei, the
internal arcuate fibres from the nucleus funiculi gracilis are to
be found at levels farther spinal ward than those containing the
arcuate fibres from the nucleus funiculi cuneati, while, on the
other hand, internal arcuate fibres from the nucleus funiculi
cuneati can be seen at levels mu(^h higher up than those in
which the last internal arcuate fibres from the nucleuo funiculi
gracilis are situated (Fig. '.)H0). Miss Florence Sabin finds two
nuiin masses of arcuates connected with the nuclei funiculi gra-
cilis et cuneati — (1) a lower mass probably common to the two
nuclei, l)ut maiidy arising from the nucleus funiculi gracilis, the
majority of wbich decussate in the raphe (Fig. 381), a distinct
bundle, however, turning forward into the stratum interolivare
lemnisci of the same side, and (2) an upper larger mass orig-
iiuiting from the anterior half of the nucleus funiculi cuneati,
apparently undergoing complete decussation in the raphe (Fig.
;5iS()). Between these two masses of arcuates is an area of con-
siderable width, correspoiuling to the posterior half of the nu-
cleus funiculi cuneati, in which no distinct bundles of arcuate
fibres can be made out.
The developmental method has thrown much light upon
the distribution of the axonos from these two nuclei. The
study of them is rendered easier by the fact that the axones
from the nucleus funiculi cuneati become medullated some
time before those from the nucleus funiculi gracilis. The
former are already medullated in the human f(etus ']0 cm.
long, while the latter receive their myelin sheaths first when
the ftetus has attained a length of from IJ-I to 158 cm. It is
possible, therefore, to follow the course of the fibres upward
separately. Without going into the details,* it may be
* For these tlie reader is referred to the Inrfje moiiojinifili on fondtielioii
paths i)iil)lished l)y P. Fleclisis,' in 187G. (o }iis Pljm dcs nicnschliflien Gc-
hirns, Leipz. (18H3), and his articles in Neurol. Centralbl., Leipz., Hd. iv (1885),
GK()rPIX(J AND CHAINING TOGKTIIEK OF NEUKONKS. 5<',0
8tiitc'(i ill j^aMUTiil that these studies have sliowii that the
internal arcuate fibres from the nucleus funiculi cuneati,
after liavin<f crossed in the raphe, run cereltralwanl in the more
dorsal ])ortion of the stratum interolivare lemnisci to form in
the pons the more hiteral portions of the lemniscus medialis,
A part of tliese fibres at the level of the inferior colliculus of the
corpora (luadrigemina pass dorsalward, according to von Uech-
tercw, to enter the region which he designates as the corpus
paral)igeminum,* some of them going on to the superior collic-
ulus, apparently to terminate in these gray nuisses. The ma-
jority of the fibres, however, do not go so far dorsalward, but
passing somewhat laterally, on account of the red nucleus,
above this body, turn still more laterally to become connected,
most probably, as we shall see later, mainly with the ventro-
lateral group of nuclei in the optic thalamus, but jiartly with
the nucleus hypothalamicns (Luysi), and partly with the nucleus
leiitiformis of the same side and of the opposite side. The
point of importance to remember at this stage in our descrip-
tion is that the majority of the fibres of this portion of the
medial lemniscus extend through the cerebral peduncle, by way
of the tegmentum, into the hypothalamic region.
The fibres from tiie nucleus funiculi gracilis occupy in the
stratuni interolivare lemnisci a region rather more medially
S. 97, and \U\. v (188G). S. o4fl ; and also to the following publications by W,
von Hf'chtert'w : (1) Die Lcitungsbahnon ini fichirn unil Riickcninark, Lcipz.
(1804). also II Aufl. (1809); (2) Fcber die liintercn Wiir/i'lii. don Ort ihrcr
Endigung in der grauoii Kiickonniarksubstanz und ilirc ecntrale Fortsot-
zung. Arch. f. Aiiat. ii. Physiol., Aniil. Abth., Lcipz. (1887). S. 126-i;{6.
Ui'bcr die Sclileifcnscliicht atif Griind dor Hcsciltate von nach der entwick-
ehingsgeschichtlicheii Methode ausgefiihrtcn I'ntersuchungcn. Arcli. f.
Anat. n. Physiol.. .\nnt. Abth., Lcipz. (ISO.')), S. 870-30.'). The vidiinbie
studies of inyeliiiizalion by E. Edinger: Zur Ki-nntniss des Verlaiifi's der
Hinterstrangfaserii in der Medulla oblf)ngata und im hinteren Klcin-
schenkel. Neurol. Centralbl., Eeipz.. Rd. iii (188")), S. 7:?-7fi: of A. Rruce :
Illustrations of tiie Nerve Tracts in the Mid- and Hind-Brain, etc.. Edinb.
and Eond. (1802); of L. O. Oarkschewitsch and S. Freud: rel)er die
Hezieluing des Strickkiirpers zuin Ilintorstrang und Hinterstraiigkern,
nebst Hcnierkungen ueber zwei Felder der Oblongata. Neurol. Cent rail)!.,
Leipz.. Bd. v (1886). S. 131-120; and of A. Cramer: Meitrage zur feinoren
Anatomie der Medulla oblongata, der Briicke, etc.. .lena, 1894, shoidd also
be consulted.
* I have not b(>en able to satisfactorily locate this body, notwithstanding
careful studv of the serial sections.
>' I
\]
ti
T
11
'I'
I
L'
570
THE NERVOUS SYSTEM.
und vciiti'iilly sitiuiliMl than those from the miclt'us fiiiiiciiU
ctiiu'iiti, thoutfh it woiikl appear that no sharp line of division
caji ho drawn between them, the fibres of the two systems inter-
niixinj?, especially at hi;;lier levels. A little hi<j:lier up a })orti(>n
of these (ihres terminate a])parently in the so-called "nuclei
reticulares tegmenti jjontis," those masses of gray matter situ-
ated near the niphe in the most ventral portions of the purs
dorsalis pontis. The majority of the fibres, however, are con-
tinued through the pons as the more medial ])ortions of the
lemniscus medialis.* In the tegmental portion of the cerebi'al
peduncle these fibres lie medial and ventral to the bundle from
the nucleus funiculi cuneati ; the nu-dial lemniscus, made up
largely of the bundles from the two nuclei of the dorsal funiculi
in this region, assumes, therefore, a sickle-shape. The fil)res
from the nucleus funiculi gracilis pass on through the tegmen-
tum of the cerebral peduncle to the diencephalon, where, as will
be pointed out later, the majority of them probably terminate by
end-ramifications in the ventro-lateral regions of the thalamus.
^'on Hechterew's scheme of the axoiu's ])assing out of the nuclei
of the dorsal funiculi is reproduced in Fig. llS'-l.
Studies by the method of Miirchi, after destruction of the
nuclei funiculi gracilis et cuneati in aninuils (Singer and Miin-
zer, Ferrierand Turner, F. W. Mott, A. Tschermak), have shown
that while the majority of the fibres exteml forward as far as
the thalamus, many of them terminate in the gray masses on
the way (formatio reticularis grisea, nuclei pontis, colliculi of
corpora quadrigemina).
Singer and Miinzer,f experimenting upon oats, destroyed
the spinal extremity of the nucleus funiculi cuneati on one side,
and studied the ascending degeneration with the delicate
method of Marchi. They found degeneration of the myelin
sheaths of the fibrte arcuatae intcrm^, corresponding to this
part of liurdach's nucleus, and were able to follow the fibres
across the raphe into the ventral part of the stratum inter-
* The most medial buiidles in the vo'/ion of the loiniiiscus arc miidc up
in all prohahility not of ecntripetal but of eentrit'iifjal tilircs. They hecoiiie
meduUated much later than the rest of the fibres ol' tlie icmiiisciis. Tlie
nature of these fibres will be discussed in connection with tliose of ttie h'm-
niscus medialis in jjcneral furtlicr on.
t Singer. J., u. K. Miinzer. Denksehr. d. Akad. d. Wissenseli., Wien,
Math.-naturw. CI., Bd. Ivii (1890), S. 569.
UKOUPIN(i AND CllAlMNU ToUETIlKK OF NKLltoXKS. .-,71
c c
*
I
li
1'
I
l"r
; If
i''i'l
II,
i i
n
,- 1
1
li
572
TIIK NKI{ vol's S VST KM.
olivari' Icriiiiisci of tho opposite side. Tlic (ibrcs hero iissunKMl
a l(»ii<Mtu(liiial direction, and rould be followed tbrougli tliu
I'm. us;?. — A triiiisvcrsc scctinii nf tlic in(<hill;i at (lif lower end of ttii' nnclcus
oliviiri>> iutiTior. showing; tlic (lijicncnition wliiili follows (Itsliiictioii ol' tlic
imrlctis funiculi Knicilis. (Aflcr Kcvricr and Turin r, I'liil. Tr., I.onil.. vol.
cl.xxxv, 1S!U, 15, |il. Ixviii. Fi^. .l. ) A'.ii.c/., viiilral cxtrcniily of the nucleus
funiculi jinu'ilis; i.ii.f.. lilinc an'iiatic interna'. dcKcncrattd on the side of
the lesion: /'..«., stratum inlemlivare leninisci ; i.iiA-ii., nucleus funiculi
cuueati, pars medialis ; i-.ii.fii.. nucleus fnniiiili cuneati. pars lateralis : m.ii.f.,
niidille annate lilu'es in part degenerated on side of lesion : i.o.. nucleus
(ilivaris inferior: Was., traetns spinalis .\. triKeiuini; /'//, p.vrainis.
lemniseu.s meditilis tis far its the hypothabimie region and ventro-
liiter.d part of the tluilaniiis. Farther than this they were
untible to tniee defrenerated fibres.
Ferrier and Turner* destroyed the nucleus funiculi gracilis,
* Ferrier. !>.. ami W. A. 'i'liruer. A Ueeord of H.xporimeiils Illustrative
of the Symiitoniattiloi^y and |)(>e;('nerat ions followiiijj liesjoiis of the Cere-
belluni, L'te. Phil. Tr.. Loud., vol. clxxxv for 1S!)4 (15) (IHlir)). pp. To.VTdl.
— .Mso, .Vn Rxperiineiitiil Roscareh upon ('ereliro-Corticiil Afferent and
Efferent Tniets. riiil. Tr.. T.oml., vol. exe (1S!)S). pp. 1-44.
GlforiMNC AND CHAININCi T(KiETIIKIl OF NKrUONKS,
iU
3
or tlu' nucleus? funiculi cuiiouti, on one side, in the monkey,
with the aid of the {fjilviino-ciiuterv, and studied the ascending
defeneration with Marchi's method and Weigert's method-
They ohtained always dej^eneration in the corpus restiforme on
the side of lesion, hut failed to })roduce degeneration in tho
same hundle on the side opposite to the lesion. They studied
also the degenerations in the fihra' ar(!Uata' interna' of the same
side, and in tiie lemniscus medialis of the opposite side, and
showed hy the degeneration method that the fibres from tho
nucleus funiculi gracilis go to tho ventral part of the opjjosite
lemniscus medialis (Figs. liH'.i and 384), while those froin tho
■^.
m
Fl(i. 3Sl. — Tniiisvcrsc sccticm of tlu' iiicilnllii ulilimKiitn fnmi tlic same case as tlio
prcccdiii;,' sniiicwliat lii^'licr \i\). (Al'Icr iMrrici' autl TuniiT, ihiil., pi. Ixviii,
I'iii. a. I Lfttcriiin as in the imcciliiij,' tifjurc.
nucleus funiculi cuneati go to the dorsal part of the same fibre-
mass. The latter relation is well shown in Fig. 3S5, which
re])resents a section stained by Weigert's method from a case
in which Ferrier and Turner had cut the corpus restiforme and
?(.»■'
kl».
..M
i
n
674
TITK NEIIVOUS SVSTKM.
destroyed tlic nucleus ruuiculi eiiiieiili | IJurdacliiJ on one side.
They could not traeo (le<,'eneriited fibres l)eyond the tlialunius.
Fid. 3S5. — A tViiiitiil sccticpii tliiiiiii.'li llic flKPiiiliciicciiliiiliiii III' ii iiiiiiikcy iil'ttM'
ilfstnictiiili III' till' iiiiclciis I'liiiiciili cmu'iiti and iil' tlir ruiims ri>til'iiriiii\
SliiiiiiiiK •>>■ Wci^'crfs iiiitliiid. ( AI'tiT ImtiIi r and 'rniin r, I'liil. Ti.. Lmnl.,
viii. t'ixxNv. i^i'}. i?., |i'i. ixix, I'ij;. ."i. I /»;, ii'Mini^^iiis iniiiiaiis ; dcKi'ncialinn
in its dorsal imrtiiin. In the cciTlicllnin nn the rijjlil side nf tlii' ti^jnrca laij-'i,
ran-sliai)i'(l sclcniscd area iit.c.l. \ Cnrnicd chiefly by llic din it (lines I'loni Ilir
nuiliiis rnniculi ciincali, is oliscrvalilf : Dwins in llic lad llial llic i-csiil'iirni
liiiily was also dcstrdycd. the sclerosed area conlaiiis in ailililioM llhrcs lioiii
the nin'le\is t'nnicnli gracilis and IVoni the Cascicnlns cci-ehcllosiiiiialis. c.i-.l..
trad hctween the ccrehcllnin and Dcileis' nncleiis : I'k.v, tradns spinalis N.
trimniini, degenerated on the lel'l side owin^' to section of the nerve hctwceu
the v'aiijilion senillnnare and the pons; «). nuclcns olivaris snperior: r.il.v.,
nncleus dentutiis ccrclielli : I', N. trincniinns ; 177. nucleus N. facialis : Mil.
N. vcslilinli.
K. W. Molt,* ill a most eonvineinii; series of experiments,
deseri])es the course of tlie tihres from the nucleus funiculi
gracilis et cuneati throui^h the internal arcuatcs, deeusstitiou
* Mott, F. W. Exporiiiiental Eii(|niry upon tlie AfTorpiit- Tracts of tho
Central Xcrvoiis System of the Monkey. Brain, Lond., vol. xviii (ISO."}),
pp. 1-20.
d> I
"'^--^..
(rllOLIMNd ANK ( ll.\ININ(i TCMiKTIlKIl (»!•" NKllfoNKS.
• > f>
of tlio liMimisciis, iiitcmliviirv liiy<'rs, imd iuf(linl li'riinisciis m
fiir iis tlic (lit'iici'pliiilnii, lie foUowi'tl dt-jfriu'ratcd lihrcs in
tlic moiiki'y as fur as the vt'iitro-lali'ral ])arL of tlio tlialaiiiu:!,
where the (lefj^eiierutioii iippcared to cease.
Tscherniak * has very reeently attacked the ])rol»lem af^aiii
ill I''le('iisi<,''s lal)()ratnry at Leipzij;. lie destroyed tlie iiiiclei
of the dorsal funiculi on one side in three cats, .md studied
the de^'enerations by the method of Marchi. lie distinffiiishcs
four neurone systems, the perikaryons and dendrites of which
are situated in the nuclei of the dorsal funiculi: (1) An un-
crossed system from the nuclei of the dorsal funiculi to the
cerebellum; ('i) a crossinj? system fntm the nuclei of the dor-
sal funiculi to the cerebellum; (:5) a crossinjif system from the
nuclei of the dorsal funiculi to the thalamus; and (4) a cross-
in<f system from the nuclei of the dorsal funiculi to the cere-
bral cortex, t
The firf<t si/sft'iti (uncrossed system from the nuclei of tho
dorsal funiculi to the cerebellum) originates nuiinly in the pars
lateralis of the nucleus funiculi cuneati [BurdachiJ, the medul-
lated axoncs passing partly as tiltra; arcuatse externie dorsalcs
into the corpus restiforine, i)artly directly from the anterior
extremity of the nucleus into the cori)US restiforme. Col-
laterals from these axones are given off to Deiters' nueleua
in passing. Inside the cerebellum where the fibres of the
corpus restiforme divide into two bundles — one lateral, tho
other medial — the fibres of the system under c(»nsidcration
enter the medial bundle and pass through it, giving off col-
laterals to the cerebellar nuclei, especially to the nucleus
fastigii of both sides, finally terminating in the vermis inferior.
This neurone system behaves much like the uncrossed dorso-
lateral spino - cerebellar system (PTechsig's direct cerebellar
tract, the fasciculus spino -cerebellaris dorso-lateralis), and
* Tschorrnak, A. rebcrden ccntralon Verlauf der aufstcigendpn Ilintor-
stran<,'liHhnoii and dorcii BezieliiuiKen zu den Bahnon iiii Vordcrseitenstrang.
Arch. f. Anat. u. Physiol., Aiiat. Abth.. Leipz. (1808). S. 2D1-40O.
t The Gorman terms arc: (\) Dux inHjckre\izte Hintcrxlmngkcrn-hlein-
hirnsysfein (unyekremte dorsnh JVucleo-Ofrehellnrfiystem): (2) Das kreii-
zende fliii/ersfnnn/kern-I'ncinln'rn.si/xff'm (kri'uzcnih dorsale Xnrho-Cfre-
liellarsi/steui); (8 u. 4) Die /ni(li-n krmziiidi')) IlinterstniiKjkcni-Gmxx-
hirnHjiHteme (J/ntf<'rt<frangkern-I/aii/)fxrfilpifimsi/.s(emp); (3) —Dan ITititer-
MrdUfikern-Sehhugelsiistem; (4) = Das llinterstrangkem-OrusHhinirinden-
xyxtem.
\
nt
'^ \
\
TIIK Ni;i{ vol's SVSTMM,
i. .
3
u('C()r(linj,'ly tlio lutcrul piu't of Hiirdacirs iiii'-Iciih, or ko-cuIIimI
nucUnis of HIiiiiuMiiiu, prcrtcnts (H'i'tiiiii uiialo^fU'S with tlit'iui-
clciis tlorsiilis (('l!irk(>'s coluiiiu) of the spinal cord, a poiiii to
wliicdi ('. S. SluMTingtori, iiml also JMimu'iiau, liav*- alrt-adv
culkMl attiMition.
The si'viiml ni/sfnii (crossing system from the nuclei of the
dorsal fnni(adi to tho ccrchcllnni) originates mainly in the
nucleus funiculi gracilis |(iolli], hut also in part fnun tlH> pars
medialis of the nucleus funiculi cuncati [ HurdachiJ. Tlu' nicdul-
hitod axones run as fihra' arcuutif interiuw to tho raphe, mixed
with similar arcuate fd)res of the tiiird ami fourth systems. Hav-
ing arrived in the stratum interolivare lemnisci of the opposite
side, the medullated axones of the second system run hetwceu
the ])yramis and tlu* nuch'us olivaris inferior, thence along tho
ventro-latoral periphery of the medulla in the lihrio circuin-
olivares, partly around, and i)artly through the nuclei funiculi
lateralis, to reach the area in which are situated the lihres of
the fasciculus spino-cerebellaris dorso-lateralis (direct cerebellar
tract). Mixed with the fibres of tin; latter, the fibres of tho
system we are considering enter tho nu'dial half of that bundle,
lateral from the tractus spinalis nervi trigemini, which, head-
M'ard, grows so rapidly in volume, and further on the fibres are
situated in the niedio-ventral i)art of the corpus restifornu'.
After giving off collaterals to Deiters' nucleus, the fibres of this
system enter the lateral bundle (of the two fasciculi into which
the corpus restifornu' divides), give off collaterals to the nucleus
dentatus, ami ultimately termiiuite in the cortex of the vermis
superior, chiefly on the corresponding side, but partly by way of
the superior cerebellar decussation in the cerebellar cortex of
the opposite side.
The f/iir/I nifsfcm (crossing system from the nuclei of the
dorsal funicidi to the thalamus) and the foiniJ/ si/s/cn (cross-
g system from the nuclei of the dorsal funiculi to the
cerebral cortex), as described by Tschermak, will be consid-
ered a little further on, wlien the lemniscus medialis is dis-
cussed more in detail (Chap. A'LMl). In the same place the
results of the studies of luunan pathological cases will be
taken up.
Tho method of Colgi has afforded interesting results, espe-
cially concerning the collaterals of the neurone systems originat-
ing in the nuclei of the dorsal fiiniculi. The work thus far with
OU()UIMN(J AM) CIIAIMNCJ TOdKIIIKU (»K NKl'ltONKS, 577
this proctMliirc! lias hccii tloiic liy IlcM,* v. Kiillik»'r,f Uamoii y
t'ujal,Ji""l Hlumcimu." 'I'lic collattTals from t lie axoiics of tl>o
in'iinmc Hyst(^iiis on llio way to the (•crchi'lliuii have hcon re-
fi'rrc'il to iiliovi). Still niorn intcrt'stiiij; uro tho flndingrt regard-
ing tlio collaterals from the iixones of the neurone systems
pertaining to the lemniscus medialis. Thus from the llhra*
ureuatiL' interna', hefore reaching the decussutio lemnis<'oruin,
thero are collaterals given otf to the nucleus N. hypoglossi, and
to the forniutio reticularis grisea (in this region represented hy
tile nucleus centralis inferior Flechsigi and the nucleus lateralis
inferior Kle<"lisigi). On the far side of tlu- raphe where the
niedullated axones run in tho stratum iniendivarc lemnisci,
long collaterals are given oil' which 2>ass chiefly hy way of the
hilua into tho cavity of the nucleus olivaris inferior to termi-
nate in among the j)crikaryons and dendrites situated in the
much wrinkled gray capsule which this body re])resents. Pass-
ing headward, the main axonos enter the lemniscus modialis,
arrivi!ig thero hy i)lunging through between the transverse
tihres of tho corpus trapezoideum, and then follow the course
of the loniiiiscus, many fibres going as far as the diencephalon.
In the pons where the lemniscus medialis forms the iloor of the
pars dorsalis poutis, largo numbers of collaterals are given oi!
to the adjacent masses of gray matter. Among those nuiy l)e
mentioned (1) collaterals to the nucleus centralis nu'dius,||
especially to its ventral part ; and (•*) collaterals to tho nuclei
pontis, those large masses of substantia grisoa situated among
* IIi'lil. H. Bcitriiiji' /iir fcincrcii Ariiitmnio dos Klcinhinis iind ili's
TTirnstiunnies. Arch. I", .\iiiit. u. Pliysiol. Aimt. Al)tli., Ii«M|iz. (18i)3), S.
4;jr)-446.
+ V. Kiilliker. A. iraiidbiicli dor Gewpbelehrc dos IMt'iiscIicn, 6. .\iifl..
L.'ipz. (18f)6).
i Rumnn y rajal. S. 15citr!iijo ziiin Stiidinm dor ^fodullii ot)lonfj:!itfv. etc.
Dpiitsclio Ucborsetz. von lircslcr, Iji'ip/. (IMiJO'i.
* Rliimoiifui. Dcs iioyaux du cnrdon postorionr ct la sulKstaiice de
Hnlundo dans la bullio. Xcurol. Coiitralhl.. Loipz., Hd. xv (1896). S. 1129.
II This niiolous. so di'sijinatcd l)y P. Mcchsijj, iippcars to correspond to
W. V. Rochtorew's Xurleus rcficvlaris tvgmenti poutis; the hitter author
se[)arate.s the ventral j)ortion of the nucleus, that rest in j; dirictlv upon
or even penetratinjj ainonfj the fibres of the medial lemniscus, from the
main mass, and calls it tho medidler Schleifeiikerv. to distinfjuish it from
the more laterally placed nucleus lemnisci lateralis, or laterahr Sr/i/eifen-
kern.
U:'
h
jjtil
I
~s
TIIK NKKVors SYSTEM.
lilt' fiisci<'uli loMjfitiKlinulcs and libra' transversa' in tlu' par«
i)asilaris pontis {V'Vfi. oSi;).
vr
Key.
red
WHM
blue
A'u.l s.
l^u.U
jVul
VJo/ef 'fl^
FU). 3Stt. — .A, transverse sectidii tlirminh the posterior liiilf of tl:e pons. Tlie left
liillt' of the iUusI ration corresiHinds to tiie anterioi-, the rijiht iialf to the pos-
terior portion ot' 1 hi' pons. ( .M'ter \V. von lieeliterew, ISiM, somewhat modi-
tied.) .Vi(.c..v., nncleiis ceiilnili.-. superior ; .V»././., niieh us lemnisci lalenilis;
.V((.()..v., iiueleiis olivaris superior; .V».y<., niiehi pontis; Sn.r.t., niieleu.s
retieuhiris te>?nienti ; A". I'., radix X. tri);eniini ; li.il.ii.W, r.idi.\ de.seendeim
ill
(iWoriMNO AND ClIAININti TOOHTIIEU OF NEUR0N?1S.
;•(!
In the nu'senceiilialon ('(dliitcnil hraiiclH'.s (mid ])(>ssil)ly ter-
iiiiiiiils of stem iixoncs also) j^o from the axoiics of the Iciimisous
iiK'dialis to (1) the imclcus collicnli iiiforioris, (•*) tliu strata
firisca colliculi siii)i'ri(iris, {'.]) the mick'us lateralis superior
Klcclisi^'i, (4) tlu' inicli'us centralis superior, (5) the nucleus
coinniissunu posterioris {ohere (huhinoluriutik-ern of Darksclie-
witscli), (<i) the stratum <iris(iuni centrale {cciitnilv lliihlvit-
(/raii), and (7) the substantia ni<»ra.
(liirsfii(<'|>liiili(;i ) iicrvi triKiiiiiiii : >7. ;;;■.(•.. striitmii Krisciini (■cntrali'. Hid —
l.i, lilircs (iC the IcimiiM'Us incdiiilis |m rtiiiiiiiiK In tlir iiucUiis riiiiiciili cmicati ;
III, scMtlricd Ixiiiillcs ill tlic Iciniiiscus iiicdialis; /,', iT;;i(p|i of scntlcrctl (il)ri'S
wliirli divcliip late ill the lateral licld iit' the ruiiiiatiK rcliciilaris ; /.'», Iciii-
iiisciis laliialis. YilUnv — l(i. lilircs of Iciiiiiistus iiudialis nriniiialiiij; in
liiu'ltiis I'liiiiciili gracilis : .'.', lihns ('nuii llic region of tlif (•(illiciiliis inrcrinr
III llii- iiiiclciis r.linilaris tc;;iiu'iiti and to tlic iions. Viitlct — ./.■;, (il ires of
I'asrii iiliis cinlralis tiynicnli iniitnilf ll(iiiliiiili(iliii) : J.'f, tilirt's |iassinK liy
tlic ra|ilic rroni llic nuclei iionlis tn llic rminaliii reticularis ni'isea ; AS, lilircs
(il'tlie spinal Imnille I viin iScclilerew) nl'llie linicliiuni pontis; .(.■;, .>'.'', .'iJ, dif-
fereiit linndlcs in tlic linicliinin ciinjiinctivuiii. /i7»(' — .}, fasciculi liinKi-
tudinales ( pyraniidales) ; ^li, lilircs (if medial accessory liuudlc in leuiniscils
nicdialis (In nintnr nuclei (ircercliral nerves) ; .',ii. lilircs of ccrclmil liundleof
liracliinni pontis; ■'>(), frontal cerclirocorticopontal path; .W, Icniporo-occipitul
ccrelirororlicopontal path. (Im'ii — !', fasciculus loMKitndinalis nicdialis ; ,s',
lilircs wliii h represent the ponlal continuation of the fasciculus lalenilis iiro-
priiis (if the spinal cord; ,}'<', coniniissnral liundle lyint; vcntnilward from the
linu hiuin coiijunctiviim.
!!. transverse section through the hiiiili stt'ni ; level of pediincnii cere-
hri. The riKlit half illustrates the level of the colliciihis inferior, the
left half tliat of the colliculus suiierior. '.\ftcr \V. von licchtcvcw . isut,
somewhat inodilied. ) .l(y.c., at|Uediiclus cercliri ; ('.</. i;i., corpus niiiiciila-
tiiui mcdiale ; Cm., corpus maniinillare ; Ck.. colliculus superior ; .V./l',
radix N. trochlearis; Sii.c.i., nucleus colliculi inferioris; Sii.f.l.m.. nu-
cleus fasciculi lonKitudinalis incMialis or nucleus coinmissnne posterioris
(tibvre.rOntliimiiliirinskirii of Darkschewitsch ' ; Sii.l.l., von liechlerew's Ctir-
pnn iiiiriihiiii'iiiiiiiiiii : Sii.l.s., nucleus lateralis superior of Klechsif; i inirlfiis
iiiiKiniliiiihin of von IJechterew) ; Sn.ii.lll, nucleus nervi oculoniotorii ;
Sii.r., nucleus rulier ; S.ii., suhstautia iiiura ; Sl.iii-.c., stratum ^'liscum
cetitnile. /iV(^ /.'', lihres of lemnisciis lateralis wliicli enlei' colliculus in-
ferior; ,'.'', lilircs of hrachinm «|UadriKeniinum iuferiiis from tlu' ((illiciiltis
inferior of the siime and of the opposite side ; /.;, lilircs of the lemniscus
nicdialis oritliualinn in the uticleus funiculi cuueati ; /■>', lihres of the lem-
niscus uiedialis jioinfj; to the corpora i|Uadrij;cmina ; Id' , .scatlered humlles of
the lemniscus which fin over into the liasis peduncnli ; I,', region of the scat-
tered lihres ilale to develoip of the formatio reticularis. )'<'lliiir — /'*. lilircs
of lemuiscns nicdialis from (he nucleus funiculi (.'lacilis; JS. lihres from the
nucleus colliculi inferioris to the ihalamus laccordinj; to von iJechterew) ;
fill, lihres from the colliculus su|ierior to tin cerehral cortex. ]"ni!il — .;;/, ,},■>.
4.1, lihres of the hraihium con.innclivum hefore their entrance into the red
nucleus; .'(7. is. lihres from the red nucleus to the nucleus Iculiformis. the
tlialauius, and thecerehral cortex i tlieseare the radialionsol' tlu' retl nucleiisi ;
.i.'i, lihres of the fasciculus '-cntnilis tcKmeiiti 'i-nitnilf llitiihriihiihii •. (imii —
.'', fasciculus longitudinal is nicdialis : .;/. lihres of the dorsal jiart of the coni-
niissura posterior ; .;/', lilucs of the ventral part of the coinuiissura posterior ;
i'7, fasi-i<'tilus rctrollexiis Meyuerii : ..','. fasciculus thalamomammillaris ' \ic(|
(V.\nyrii; ,-'.V. fasciculus pedunculomammillaris pars hasilaris (pcdumnlus
oor|ioris maminillaris ' ; -''S, lihres from tlii' suhslantia Ki'isea of tlu' coIMimiIus
superior to the rcKioii of the nucleus rulier of the opposite side. Uliif — ,),
fasciculi lonnitudinales; I pynimidalesi ; 'ill, lihres of frontal cerchrocorti-
copdutal path (medial 'hniidle in liasis jieduiuaili i ; '>!, lihres of occipito-
temporal cerelirocortico|iontal path ' lateral liuudlc in liasis |ieduuculi ' ; ,.'<>,
lihres of the accessory hundle of the leniiiiscus; ,■''.", lihn's conncctin).' the
suhslantia nit:i'a with thecerehial hemispheres.
m
Phi
m
i'\'
V
m
'H
rT-?
H
580
TUE NERVOUS SYSTEM,
Further on in the hypothahimic region of the diencephiilon
the studies with Golgi's metliod have thus fur not yiohled
wholly satisfactory results, owing in large part to the (ioniph^x-
ity of tlie region and the paucity of our general knowledge
concerning it. Held, however, observed with silver cliromate
impregnation large, coarse axones which enter the ventral part
of tlie thalamus, where they divide manifoldly, and form tliiclc
feltworks of fine branchings extending for considerable dis-
tances, lie made out that these axoues come in part from the
bands of white matter dorsal to the nucleus hypothalamicus,
(corpus Luysii), and concluded that they correspond to tlie
fibres of the sensory cerebral paths (botli lemniscus medialis
and brachium conjunctivuni), and accordingly made the state-
ment that at least a portion of these paths does iu)t extend all
the way without relay to the cerebral cortex, but that the neu-
rone systems concerned terminate definitively in the thalamus.
This observation is a pleasing confirmation of the views based
upon the study of pathological degenerations in liuman beings
with Weigert's method (von Monakow, Mahaim), and upon the
examination of the central nervous systems of experimental
animals (Singer and Miinzcr, F. W. Mott, Ferrier and Turner,
Tschermak).
The studies of Blumenau with the method of (iolgi proved
that the axones of the cells of tlie nucleus funiculi gracilis,
together with those from the pars medialis of the nucleus fu-
niculi cuneati, pass chiefly in arches to the raphe, where they
cross to the opposite side and assume a longitudinal direction
in the stratum interolivare lemnisci. A number of these fil)res
bifurcate in the interolivary layer, one limb asceiuling, the
other descending. He could follow the axones of the large
perikaryons in the pars lateralis nuclei funictdi cuneati into
the corpus restiforme.
It is obvious, therefore, that in addition to carrying itn-
pulses for long distances cerel)ralward, the neurone systems
under consideration are well adapted for playing an important
role in connection with the complicated reflex activities, the
centres for which, it is believed, are situated in the medulla and
pons.
CHAPTER XL.
I ■ I!'
'hi
THE XUCLRUS nOIiSALIS ANI> TllK AS('E\I)IX(! DOKSO-LATERA L
SPIXO-CKKKBELLAR XKIKONK SYSTEM.
Clarke's column or tlio nucleus dorsalis — I'crikiiryons and dendriti's — .\xones
of direct cerebellar tract — ^lyelinization — Uelation tiicdrpus restifonne
— Terminations in cerebellum — Collaterals to nucleus dentatus.
{ail b) We have seen that colhiterals and terminals from a
certain definite rogion of the dorsal fniiieuli of the spinal cord,
namely, those from the middle area of the fasciculus cuneatus
(part of Fleschsig's middle root zone), enter and ternunate in
the nucleus dorsalis (Clarkii, Stillingi). This longitudinal
column, described by Lockhart Clarke * as the "posterior vesic-
ular column," and called " Clarke's column " by von KiJlliker,
seen in cross section of the thoracic spinal cord on the medial
side of the neck of the dorsal horn of gray matter on each side,
extends uninterruptedly from the level of the third lumbar
nerve below to that of the seventh cervical nerve above (Fig.
3S7, Cand D). Corresponding masses, separated from the main
column, are found in the sacral and cervical regions ; that in
the sacral cord is situated at the level of origin of the second
and third sacral nerves, atid is known as the " sacral nucleus "
of Stilling.f The "cervical nucleus " is situated at the level
of the third and fourth cervical nerves. Tn many respects the
pars lateralis of the nucleus funiculi cuneati, or Hlumenan's nu-
cleus in the medulla, corresponds to the nucleus dorsalis of the
spinal cord.
In the nucleus dorsalis are situated rather large multi-
polar cells with numerous much-branching dendrites (Fig.
* Clarke, .T. Ij. Phil. Tr.. Lond. (1851). Pt. II.
t Stillinir. 15. Xeuo rntersiiclumgen ucber den feineren Ban des Hdck-
cnmarks. Cassel (1859). 4to.
581
M
r)S2
TIIK NERVOUS SYSTEM.
;5S<S). Hanion y (.'iijul and von Lciiliossik ilivido the colls in
this nucleus, the niujority of which are multipolar, into two
groups — (1) stellate or polygonal; {'i) spiiuUe-shapi'd ele-
B
k^^f""
I)
F
(i
FKi. 3S7.—('r(iss sections tliriiuuli the liiiniiin siiiiiiil van], stiiiiicd witli caniiiiip.
(Al'lfV II. ()li( rstcimT, AiilcitmiK lieiiii Sludiiiiii dcs Haiics dcr ncrviiscn
( 'ciilniliirv'uiic iiii ^csiindcii uiid krankcii Ziislaiidc, III, Autl., Lcipz. u. Wicii,
ISiMi, S. :>:.'7. Kip. ilti-Kl-'.) A, transverse .seetinn at tlie level (if (iii; T;/,
edininissiini ^'isea : .ly>, apex eiiliiiiniie <liii'siilis ; fVi, enniniissura ventralis
altia : Tc, eanalis centralis ; Cm, eimiinissiira iiiediilla' s|)inalis; ('/■«, ciirnu
ventralis; Crii. cornu ilorsjiiis : Fun. I'linieiilus ventralis; Full, fascicnins
(uneatus BnrdiK hi : /•'»'.', t'aseieiilns K'-'K'ili^ <'<illi : /•'»/, I'lmienlus lateralis;
Fslii. tissiira niediana ventnili.s ; Fslp. sulcns nie(lianus dorsalis; A, tnictns
solitarins; I'r. lorniatio reticularis ; ha, radi.x veiilnilis ; Rj). r.idix diirsilis;
S(i. siilistantia jielatiimsii Kiilandi ; Shi. sulcus lateralis dorsalis ; Stud, seiituni
inediauuui dorsile ; Sjiil, se|)tuin iuternu'diuni diirsale ; Til, traetus iiiter-
uu-<lio lateralis. H. transverse section at the level ol'Cvi; /'cm, processus
cervicalis niedius cornu veutnilis ; Til, c-oluuina interuiediodateralis. (',
transverse section at the level of T iii; CCI. nucleus dorsalis Clarkii. 1),
transverse section at the level of T xii ; ('<^l. nutdeus dorsalis. K, tnmsversc
section at the lev(d of L v ; m, nietlial cidl f;''<iup of the cornu ventralis; /r,
lateral ventral, /(/, lateral dorsil. and c, central cell f;roup. F, tnmsversc
section at the level of S iii ; m, medial, lil. lateral-(lorsil c(dl t!roui(. (i,
tninsverse section throUKh the lower part of the tonus inodiillaris at tlii>
level of orif^in of the N. coccyKeus.
(iliollMNil AM) CllAIXIXti TOCHTIIKH OF XKlItoNKS. ;,s;{
iiiciits. .Miiiiti * has reconstructed examples ol' the nerve eells
of tliis iiiieleiis, one thousand tinu's enhirj^ed. lie asserts that
the cells are essentially l)i|)olar (in ajireeinent with Mott), and
that thov send one axi;^ cylinder upward, the other dttwnward.
Fid. 3SS. — Nerve cell from tlic nucleus dovsalis ol' ii liiiiiian eiiitiryo 32 em. lniiR.
Melliiid (>(■ (i(ilf.'i. After M. von l,eiiliii.-.sek. Der feiiure IJaii des Nerveii-
.systems, etc., I5ell.. II. Alltl., IS!*.-), S. :UT. l-'i^. 'y'-i-' Tlie axcilie of tlie eell
sliowii at tlie ui)per left of lijiure lieeoiiies the axis eyliiKler of a medilllateil
fibre of the faseiellllis eereliello-spiiialis ' or direct ccreliellar tract i.
The iixone of most of the cells situiited here pass out, thou^di
sometimes rtither indirectly, to the ftisciculus ccreltello-spinalis
(direct cerehelliir tract or l\h-liihir)isrilf)islran<jli(ilnt of Flech-
siir) of the siime side. Fle(disi<i"s f sttulies of niyelinization
(Fig. ;}S!)), and tliose of Mott,t and especitilly of 11. T.
* ■M.'iiiii. P.. Stnictm-c of Nerve Colls as shown hy Wax ^fodols. Re-
port of the Si.xty-sixtli .Meeting' of llie Hritisli Association forllu' Ailvaiice-
ineiil of Scipnco. iicld at TJvor|iool in IS'.KI. iip. 080-981.
\ Flcelisii;. P. Die Leit niiushaliiien ini (iehirn nnd IJiickciiniark. Ticiiiz.
(ISTC), S. 'iOr,.
t Mott. F. \V. Mieroseoiiical Kxamiiialioii of Clarke's Colunin in .Man,
the :\Ioiikev. and liie Do?,'. .T. Anat. and I'hysiol., I.ond.. V(d. xxii (lSS7-'8^<).
KJ I
i
:
M,
\
Ij
n^
'm.
■il-!
!:
684
THE NERVOUS SYSTEM.
Patrick* i>u secondary degenerations, made it ahnost certain
that the axones of the cells of the nucleus dorsalis pass upward
in this tract. The actual proof of this has, it is said, been fur-
FniiicttluH lateralis
-V. ' iiitiTinedio-lateralis.
.<'-
-v-
'^•^liit,,
? ? 3
N
Fio. 380. — Fniiitiil lonKittiilinal section at th<> junction of tlio purs tlior.icalis and
pars lumlialis of tlic spinal cord, illustnitinj; the relation of the nncleus dor-
salis to the faseieiiliis spinii-eerebellaris dorso-liiteralis. (After P. FlechsiR,
Die LeitiinKslialmen ini (iidiirn und Kiickenniark des Mensehen. etc., I.eipz.,
lS7(i. Taf xviii, KIk- ~.) ''. hnndle from the nucleus dorsiilis to tlie direct
cerebelliir tract, the liorizontal direction \>vu\<i maintained ntil the compact
piirt of the latter is reiiched ; c. fascicnlns cerehro-s])inali .iteralis; li, suh-
stantia allia (limitiiii; layer): c. meduUated axones from nncleus dorsilis to
fiiscicnlus spino-cerehellaris dorso-lateralis (direct cerelxdhir tnict); .r. lihre
taking a steplike course, do\il)tless heloUKinn to the direct cereh(dlar tract ;
c. (ihre hundle id' unusual course near the nutdeus dorsalis : i/. fduc liundles
\vhi(di lieiul around out of the liori/.ontal direction to descend longitudinally
(nature douhlfnl).
nished by Laura. The axones are very lonjj, running the whole
length of the spinal cord to the medulhi, whence they pass })y
Wiiy of the corpus resliforme into the cerebellum. The fibres
[ip. 47!l-4!)r). — The Bipolar Cells of the Spinal ("ord and their ('oiinectioiis.
Brain, LoikI. vol. xiii (18!)()), pp. 433-448.
* Patrick, II. T. On the Course and Destination of Gowcrs' Tract.
.T. Nerv. and Ment. Dis.. N. V., vol. xxiii (IHWi). {)p. 85-107.
'h, -
GKoriMXG AND (MIAIXIXCJ TOdKTIIKIi OK NKURUNKS. 585
which in the adult are of a very hirge calibre become medul-
lated at a later period in the embryo than those of the lateral
ground bundle.
In the thoracic cord the meduUated axones of the un-
crossed dorso-lateral spino-cerebellar tract which we are here
considerin}^ make up a rather narrow strnae at the periphery of
the dorsal half of the lateral funiculus. They thus occupy the
region between the lateral pyramidal tract and the surface of
the cord, and are situated dorsally as regards (Jowers' tract
(Fig. :J!)0). The fibres, corresponding to the location of their
Fio. 390. — Schrniatip tmnsvPTsp spction tlirongli tlu- pars ci rvicalis of tlic nic-
(lulla siiiualis. ( After II. ( )lii'rst('iiicr. Aiilcitmi}; hciiii Stiidimii dcs Baiicsdir
ii('rv(is('ii (VntralovKaiic. etc., III. .\iifl.. I,ci|i/,. u. Wicii. IS!)(>. S. -Su. I''i«. li:5. )
/>', rasciciiliis cinn'atiis I?iinlaclii ; Cn. cnimiiissiira vcntralis: Ctia. cciniii vcii-
tralis: ('»/(. (■(irnii dorsalis; '.'. lasciciilns vciif ro-lati ralis (iowcivi ; (,'S, I'as-
ciniliis sracili.s (inlli : (ISX. iiiixcd Imiidlc "f t'miictdiis lateralis; lln. dorsD-
latenil tield of fmiieiilus diirsilis : />', inteiinediary laiiidle of I'miiciiliis
lateralis: A'S. faseiciiliis e<Tel)elio-siiiiialis nr direct eerel)4llar tract iif Flecli-
si<; : /,, lassauer's fasciculus: m. iiiaruiaal /.nuc : I'l/S. fascicidus cerelim-
spinalis lateralis or lateral pyramidal tract: /'//!'. fasciculus cereliro-spiualis
veutralis or v<'nti';il pyramidal tract : A', sulistautia ;;<latiuosji IJolandi : /'<(,
radix veuti-alis: A'/*, radix dorsalis: sr. comma of Scliultze; Si;, lat<'ral
liuiitinji layer ; Sj/c. sulistaiitia Kclatiuosa centralis: ]'<!, fasciculus veutralis
liroprius; ilf. ventral litdd of doi'sil funiculi ; nii, fasciculus suli'o-marjiinalis ;
ir, (lorsal root lil)re.
cells of origin, ap]iciir first in the uppermost part of the Inm-
bar cord, and gradually incrciise in mass iis the cord is ascended.
i' t
Jij
m>
m
ill
5H6
TlIK NKUVOUS SYSTKM.
(jwiiig to the contimu'd accessictii of new iihros from the mi-
olous dorsiilis at succ;essivo levels. At the junction of tlie cer-
vical cord with the niednUa ohh)n<j:ata this t'asci<'nlus cerel)ello-
spiTialis Fh'ciisi<fi comes to occnpv the an^le Ix'tween tlie j,'ray
matter of the dorsal horn and tiie lateral snrface of tlie cord.
The fibres become disphu^ed dorsalward and help to build the
corpus restiforme, beiufj; the earliest of the fibres of the latter
bundle to become medullated (Fig. :5!)1). The fibres of the
Hwtix ili'sri iidfHS N. vestihuli.
Si t t
HhhiUv CDiitinuou.i licliiif with
till- viiitntliitirtil fanciculi of
the sjiiiiitl cord uiid above
with the /(Lsciculun loniji-
tuUinitliii medhdin. . .
Cnrpim rcKtifiiriiK' ( ti-
Itrrs tif dirt'rt rrriUvlUii'
tt'Off tir /(tsrii-idits s'/'/no
riri'liillitn'ti dorsuln/fiudis).
1 riiiliis K/iiiKdis )u'i'ri
triiji'iiiiin.
SidiKlii II till iji'liiliniiHit .
Fibrin ill fill-, iiitlii iiliciiliiriK fiiiiii
liiteriil tiiiiiii(/us.
Xiichlis iiliviiris iiilrriiir
Xiiib'ii.1 Striititin
lllifliris illtrl-illi-
itivetixoriits luiri' Ivin-
mediiilin. nisei.
Pi/niinis.
Fl(i. :!!•!. — Triuisvirsc section tlircmyli iiiumt ihiid oC incdiilln ohloiifiutii of !i
I'd'tiis 1(1 cm. lonjr. ' .\ftcr P. ricclisi-i, D'w. Lcitiiiijislialiiicii. etc., licip/..,
1ST(), Tat', xi. Vifi. •^. )
I fl-
■11(11-
' II III!
<}ll<)l'IMN(i AND CIIAlNINCi T()(JHTllKlt OV NKLllOXES. 58?
direct cerelH'lliir tract are inedullated at the fifth month of
fd'tal life (Bruce). \n fcetuses from :35 to 'iH cm. lonj?, one can
follow tlu'se medullated axoiies in serial sections up tlirouf^'h the
-t.4.c.
l'"l(i. 'AVi'i.. — Frontal section of medulla ulilon^ila and eerelu'lluni of seven months'
fd'tus at level of last (proximal) portion of nucleus faslinii. The nucleus
{{lohosns consists of several parts. ^ After Sancte de Saiu-lis. Monatssclir. t'.
I'sychiat. u. Neurol., lierl., I5d. iv. IH'IS. ]>. TAS, \'\\i. 7.) Cm., lar>;e anterior
decussation commissure; r./>., <'orpus deiitatuni sen ciliare ; ('.i\. corpus
rest i forme ; /■.", nucleus endiolifoi'Uiis ; I'lr. Ilocculus. with its iieilnncle ; F.S.I.,
filira' .semicireulares laterahs ; F.S.ni., tihra' semicirculares mediales : (I,
lilH'lens «lolii)sns; it.il.n., nnch^us lu'rvi vestiliuli ; »./.. nucleus fastiKii ;
r, r , tractns spinalis nervi irijjeniini ; t.h.c, nucleus nervi cochleiL- dorsalis.
corpus restiforme to tlieir terminations in the vermis. Tliey
pass by the anterior part (givinjjf ort" collaterals to it) of the
corpus dentatum nniiidy on its Ititeral side to ptiss out to the
cortex of the dorsal and proximo-ventral portion of the vermis,
])iirtly on the same side, but to a great extent by wtiy of the
liirifc commissure (Fijrs. '.]U'i tind :{0:}) also, on the opposi^^e side,
where the tibres enter the grtiy sul)stiince, lose their myelin
sheaths, and terminate by eiul-ramifications in timong the nerve
cells and their processes situtited there. Another smaller por-
tion of the corpus restiforme, its so-ctdled " medial buiulle,"
passes, partly mediiilly and ventrally as regards the cere])ellar
nuclei (nucleus dentatus, nucleus globosus, nucleus emlioli-
; 'I
iii
,11
■Il}('l
5SH
TIIK NEUVOL'S SVSTKM.
I
L'
forniis, and nucleus fnsli^'ii), piirtly actunlly tlir()u;,'li tlii'sc ;,'ray
Miassfs t(» tcrniiiiatf rliictly iti tlic cortex of the vermis inferior.
Some of the tilires, however, pass tlirou^'h the commissura cere-
helli inferior, otiiers throujrh tlie interfastijjial commissure.
It is not surprising', theref<ire, tiiat some tinu' after section of
the fasciculus in the upper cervical cord in yoiinj; animals
von Monak<»\v should find that there had resulted atrophy of
the c()rre.sponding half of the vermis. The area which is oc-
cupied by tiiese fibres is shown in V'\<i. 'MA. The fact that
the fasciculus curebello-spinalis,* all the way from the lower
/
Fio. ,103. — Friiiital scctiim nf mciliilla i)liliiiit;;ilii iind (•cnliilliini ot'scvcti
I'd'tlis at level <>!' pnixiiiiiil exlieiiiity nl' iHielei;s I'astiKii and iiiiel
tatus. (Al'ter Saiiele de Sanctis. Monatssehi-. I'. I's.veliial. ii. Neum
lid. iv. ISilK, 1). •.'77, \'\ii. H.I li.c. braehiuni ((iiijiinctiviini : C.r
restiCiiniie : t'.r.iL. titn'M- ((iininissiirales dorstles ; f.i.f.. titnie inriiila;
I'. I.. til)res lyiiiK latenil troiii tlie hracliiimi ennjiMictivimi. wliieli
tild-.i' iritralaslitjiales: f.ni.. tilires lyin}; medial to the Idnrliinin
tivuiii. n'.a.'eil to Deiieis' nucleus ; /•'.>'./., tilna' seiniciiculares 1
F.S.iii.. Mmv scniciniilares niediales; /.^. transverse tilires helonfti
larne anterior oiiiinissure ; if., intertastisial deeus-sition.
niontlis'
eus deii-
I.. lierl.,
., corpus
-ti^'iales;
join the
ennjune-
aterales ;
UK to the
* On aceouiit of the (iirectioii in which iiiipiilsos are eondueted hy tins
tract it is unfortunate that it has I en designated a verehtUo-spinal fascic-
uhis: it would be inoro appropriate to afiply the term Kinno-cerebelhir to
the bundle. In a revision of the nomenclature. I would suggest that fas-
ciculus sinno-cerebellarisdurso-latemUs be eoiisidereti as a suitable name for
the ti'aet.
(iUOl'I'INMi ANh ClI.MMNd n XiHTIIKI! oF NKrUOXKS. r.SJ)
tlit>riicif iTj^'ioii t(» tlif corpus ri'stiforim' in tlir iiu'dulla, is silii-
iit('<l oil the very siirfiifc of tin- cord cxplaitis why in (liseiisert liko
ctTfliro-spiiiiil nu'iiiiifiitis it is i'si>i'ciiilly exposed to injury.*
Fi<i. 394. — KioiitMl scrtiiiii tlimiiiili rlioiiiticiicciiliiilnii of tiionkt'.v : (listiU(tii)n of
nucleus t'miii'iili ciiiiciiti iiiicl cdriiiis nstirdnnc. \V('i<,'fit's niclluid. I After
iMi-rier and Turuer. I'liil. Tr.. Loud., vol. elxNxv. isill. 15., pi. Ixix, I'"if.'. .'>. )
H/_f, leniuiseus uieiiiiilis ; de-jeuenitiou iu its dorsal portion. lu cerelielhiui on
rijtlit side is a larfje. fau-sliaped sclerosed area in.r.t,', formed iliietly liy
direct filires from tlie nucleus i'uniculi cuneati ; the sclerosed area contains in
addition lilires from the nucleus funiculi gracilis ami from the fasciculus cere-
liello-spiualis. e.r.t.. tra<t lielweeu the cerebelluni and Deiters' nucleus;
Ik.", tractiis s))inalis N. trijteniini, deiicuerated on the left side ; sa. nucleus
olivaris sU|)erior; r.il.r.. niudens dentatus ccrehelli ; I', N. trijieminus;
17/, nucleus N. facialis: 17//, N. vestihuli.
A('('oi'(lin<; to I'titrick, whose studios aro anions: the most
careful we possess, a certain nuiid)er of the fibres of the ftisci-
culusdo not enter the cerebelluni throu<rh the corpus restifornic,
but pass on further hciidwiird in company with the fibres of
fiowers' tract.
* Barker-, Ij. F. <>ii Ortaiii C'lmiigi's in tlie Cells of the Ventral Horns
and of tlie Nucleus Dorsalis (Clarkii) in F,pi(leinic Cerubro-spiiial Meningitis.
Brit. M. J., Loiul. (WJl), ii, pp. I»a9-lis41.
I
M
M
I
4
It ';
.*•'
CllAlTKIt XLI.
OV (iOWIMls' TliA» T AS A ( OMI'LI'.X OK I'l MHE-SYSTRMS.
'I'lii- I'asciciilus vctitro-lult'rali.s .siipcrnciiilis ((iDWcrsi) — Dojji'iKM-iilioiis in (lie
vciiirci-Iiilcnil ri'tfioii — rpwanl ('11111111111111(111 d I' flowers' trail— Siudicsof
lidcwciilliiil, Aiiorliacli, Moll, I'alrick, Ildclic, and otlicrs — 'I'lic voiilro-
lateral eoiijimetiviil s|>iii.(-eerei)elliir iieiiroiie system — Sensory crossing
of l'!(lin;;er — The veiilro-liiteral superior s|)ino-(|iia(lriiceiiiiiial neurone
system — Tiic veiitro-lateral >|iino-tlialiiiiii(! systi'iu — {{eialions to tiie
loniniseus lateralis — I{ossolitno"s studies — 'i'lio inferior spin()-(|uadri-
geminal neurone system— The spiiid-pcdunculur neurone system do
the suiislantia nij^ra) — The spino-lciilifoiiiiiil neurone system — Tho
vent ro-lat era! spino-cereliellar restiformal neurone system.
{idl r) Tlu' cell Ixxlii'sof tlic iiciiroiK's, tho iixonos of wliicli
go to nmko the fasciculus voiitfo-latcralis supoftlcialis ((Jowei'si),
onliiiiirly known as (iowefs' tfact, iii'c sitiiatc(l in the <,n'ay
niattiT of the siiinal cord, ajjpiircntly, |)itrtly in the ccntfal por-
tion of tilt' ventral horns, jiartly in tlio middle zone of the <,n'ay
sulistance (v. Lenhossek). The axones of tho faseiculus come
in ])art <lirectly from the gray matter of the same side of the
cord (axoiics of tatttonieric iietiroiies), in ])art indirectly fniin
the gray matter of the opposite side* of the cord hy way of the
ventral commissure (axones of heteroineric neurones). Tiie
corresponding hundleof medullatcd axones in the white matter,
which hears the name of the distinguished English neurologist
(iowers,t degenerates upward on transverse lesions of the cord,
* (iuarnieri, (i., cd. A. Migiiami. Kiceivhi siii centri iiervosi di iin am-
putato. I!oll. d. Soc. Ijancisiana d. osp. di Hoiiia, vol. viii (ISHH), p. 10:5.
The reader is referred also ti/ the researches of Hdin^'er and of Molt.
t (lowers, W. I{. Diagnosis of the Diseases of the Spinal Cord. London
(1H!)T).— Hemerkuufxcn ueher die antero-laterale aufstei,i,'en(le l)ej,'eiieralion
im Kiiekenmark. Neurol. Ceiilrall)!.. Leipz.. ISd. v(18S(;). S. !»?-!»!).— Weitore
Heinerkungen iiel)er den aufsteigeiiden anlero-laleralen Strang. Neurol.
CentraUiL, Leipz., Hd. v(lH86).S. loO.— On the Anterodateral Asccndiiiir Tract
ot the Siiinal Cord. Lancet, Lond. (18S(J), i. p. 115;!; also in Asclepiad, Load.,
vol. iii (1880). pp. 278-28L
.'500
''"«4^
(JWori'INd AND ('IIAI\IN(i TodHTIIKIJ OF NKn.'ONKS. 501
a fact (Icti'rniincd hy (iowcrs liinisi'lf, and coiilirmcd l»y Tooth,
Krancotti', Harhucci, and others. The nize and poHitioii of tho
dfj^'t'iicratcd area varii's acronlinjf t<» the posit ion of tiic lesion,
uwin;,' to the eirciinistanee tiiat the trai-t is made up of liltres
which enter it at vari(»n« He;i;nients of tho cord. The tract
lirst becomes visil)le in tlie uppermost re<,'ion of the lund)arcord,
l»ein<^ situated on the surface of tlie hiteral funiculus ventrally
and laterally as rejrards the lateral pyramidal tract; it increases
notably in volume as tlu- cord is ascended. Hij^her up in the
tiioraeii! region the fibres form a stripe along the ventro-lati'ral
Flo. '.W't. — TriUisvcrsc section of spiiinl cord at level of tlie fotirtli cervical sen-
liielit to show asceiiiliii;; <le(,'eiiera(ioii of (Jowers" tnict. i After I'". W. Molt,
Hniiu, l.omi., vol. .\v, l.silii, ji. -^lis. Ki^. l.> Tlie (1<-Keiierate<l lilms an?
stained lilack in the lasciciiliis Ki"acilis. in the fasciculus s|iiiio-eeriliellaris
doi-so-laleralis. and in tlw fascieiilus ventrolateralissiipertieialis. The deyeii-
cnition risulled from heiniseclion on the ri^lil siile, at the level of T i and T ii.
.Ill
hi
aspect of the cord in front of the fasciculus cerebello-s])inidis
Fleclisigi, but among them are mixed lUiiny fibres of the fascic-
ulus ventralis et hiteralis proprius. In the cervical cord (Jowers'
bundh' forms n more extensive and more (compact nuiss, extend-
ing from the direct cerebellar trtict of Flechsig l)ehind to the
ventral roots in front (Fig. 'M'y). It would appear that nuiny
of the fibres in the tract under consideration continue up for
only ii short distance when they turn in to end in the gray
matter of the cord, thus representing shorter and longer longi-
tudinal association tnicts between the spinal segments. Thus,
M
;: ■■ <l
! S
I
:>\^-2
Till-: NKUVolS SYSTEM.
ill huiiiini ciisos, when! a spinal lesion has existed low down in
the cord the main mass of the as('endin<f (U'^eneration in
fiowers' tract can be followed as a rule no fartiier np than
the cervieal cord. In tlio case doscu'ibed by (lowers, of lesion
in the npper ])art of the liunbar enlar<;enu>nt, it was impos-
sible to follow the defeneration above the npper ])art of
the cervical enlar<jjement, and in a case of hnnbar jtaraplegia,
studied by Schatfer* with Ma'-ciii's metliod, it was not possi-
ble to follow degenerated fibres in (lowers' bundle above the
level of the root of the second cervical nerve. Moreover,
in lesions at any level, the number of fibres degeiu'rated
decreases » "ogressively as successive sections in an ascending
direction are studied. According to the observations of Bar-
bacci and others, the longest fibres of this fasciculus run in
the parts of the tract situated nearest to the peri])hery of
the cord.
The upward continuation in the medulla of (lowers' tract
has been the topic of much discussion. A num])er of investi-
gators believe that a portion of it at least is continued directly
or l)y relay into the nu'dial lemniscus, Von Hechterew, who
independently isolated the fasciculus as a separate tract by the
embryological method of Flechsig, states that it is meduUated
at the Ix'ginning of the eighth month of fo'tal life. He followed
it into the medulla as far as the region of the nuclei laterales,
where it lies close to the periplu'ry of the ventro-lateral surface.
He inclined to the view that the fibres of (lowers' buinlle ter-
minate in the more ventral of the two nuclei laterales. It was
early shown, however, by the ex]ierim('nts of Loewenthal,t that
destruction of the left lateral funiculus in the dog was followed
l)y a degeneration of the fasciculus ventro-lateralis superficialis
which could l)e followed up to the uppermost part of the pons,
where it turns dorsalward in order to pass near the brachiuin
conjunctivum through the velum medullare anterius into the
cerebellum. At tiiat time Loweiilhal named this fascicuhn
the " ventral cerebellar path." Similar experiments were made
* ScliiilTcr. 1\. Bi'itrai,' /ur Hisliilii<,Mt' dcr sccinuliircii I)(\;;ciii'i'iili<>ii : /ii-
gleicli fill licit nij; /ur Ki'icki'iiriiin'lvSiUiiil(Piiiie. iVrcli. f. iiiikr. Aiiiit., Imhiii.
Bil. xliii (1894). S. 2r)'i--2r)6.
f I.ni'wciitliiil. X. Di'if('iiiJratiiins sccdiulairos iiscciHlaiitcs dans li' Imlln'
nicliiilirii, ilaiis Ir pinil ct dans I'l'ta^i'c siiin'iicMr du Tistlinu'. IJcv. nu'd. dc
la Suisse roni., (icnrvc. I. v (ISM,*)), pp. ,")1 1 -.'>:!;!.
Ilill
i
Gliori'ING AND CIIAININO ToGKTIIKK ol" NHlKoNKS. .-,<»;{
by Auerbacli * witli tlio aid of Marchi's iiu'thod ; lio was aide to
follow tlie dej^eiK'nited iihros to their tt'i'iuiiiation in tlie voiitral
]tarts of the superior vcruns. lie found tlirce fasciculi cxteudiiii,'
from the cord to the cereljelluni : (1) a dorsal cerebellar tract
t'lilliciilun miiiiriiif.
/■"itsciiitliis tipiuii-ri'rfh<tl<iris
iliii.io IdteriiliK.
/■'(•sririilKK KiiiiKi-c'rihi'llitrin
rciiliii liitfnilia.
Vui. :{!M>. — |)i;iKranmiiiti<' rcprcsciitalioii of the ((iiiisc i)t' the (il)l('S of tlic two
|iriii(iii:il Inicls asccndiiij; from llic >|iiii;il ronl to the (•cri'licllimi. (Afltr
h". \V. Mott, Miaiii. Loud., vol, xv, ls!t;,>. |,. •,>!!). Kif;. 1.1 Tlic fasciculus
spiiio-ccit'licllaiis vciitiii-latcialis ( iowi rsi am) the fasciciilii^spinoccrchillaris
ilorso-lati Talis aic united in tlic cord and in tlic lower part of the nuMlu'la.
The latter passes into the corpus restiforme and terminates in the dorsa) por-
tion of the superior vermis. 'I"he former remains ventrall.v sitnateil uitil it
reaidu'S tlie level of the N. Irijjeminus ; passiuf; heyond lliisit forms i loop
backward to reach the <lor.so-lateral surface of the hraehiiim lon.iuncti vum.
The lilires then course liiu liwai'd and >weep round into the anterior poilion
of the superior vermis.
(Flechsiji's tract) ondiuii in the dorsal part of tlie vermis su])erior;
(•^*) a vent lid cerebellar trtict ((iowers" tract) ending in the veiitrtd
parts of the vermis; tuid (;)) a third smidler bundle arisiiifi in the
* .\uer1iMeli, T,. Zuf Aliatoinie der nilfsteiecinl deijellel'iel'ellcleli Systemc
des Hi'iciieiiinarks. .\iiat. Aiiz , .leiia. I'll. vdSliil). ,S. \.Ml-'J|(i.— /.m- Aiiatomic^
der Vorderseileiisli-iMi;;rcsto. Arch. f. patU. .\iinl., etc.. lief!.. Md. cxxi
(ISiMl) < i;t!l-','0!l.
i
mi^i
594
THE NERVOUS SYSTEM.
}■;;:
M:
I
lumbar cord and accompanying (Jowcrs' tract as far as the level
of exit of the nervus trigeminus, where it left the latter to pass
through the corpus restiforme into the cerebellum toward the
nucleus dentatus. The exact course of the fibres has also been
very carefully worked out by Mott * and by Schaefer in mon-
keys by means of experimental section and subsequent study
by Marchi's method. The English neurologists find that in
the perns the fibres "leave their ventral situation, forming a
loop over the fifth nerve ; they are then directed obliquely uj)-
ward and backward, to the surface of the superior peduncle,
forming a layer of fibres continuous with the valve of Vieussens
and separated from the peduncle by a thin layer of gray
matter; they then run downward on the posterior surface of
the peduncle as far as its junction with the cerebellum at
the isthmus, where these degenerated fibres can be seen
streaming inward to the superior vermis." The accompany-
ing diagram shows in general the course of the two princijtal
tracts which ascend from the spinal cord to the cerebellum
(Fig. :m).
In human beings, however, the upward continuation of
(Jowers' tract above the medulla was first followed by Patrick f
as far as the region of the corpora qiuulrigemina (Fig. 'M7).
lie found along with the degeneration of the ventro-lateral
spino-cerebellar bundle marked degeneration in the lateral
lemniscus. In 1800 he published in this country the results of
his experiments on cats with the aid of the method of Marchi.
He found after hemisection or total transverse lesion of the
spinal cord ascending degeneration in the region of (lowers'
tract as far as the cerebellar worm, and stated that whereas the
dorso-lateral spino-cerebellar tract terminates in the dorsid aixl
proximo-ventral portions of the vermis, the fibres of the ventro-
lateral spino-cerebellar trac*^ are ultimately distributed in the
ventral and distal dorsal parts of the vermis as well as to the
lateral lol)e.
*M()tt,P. \V. Ascendiii}; Dcj^encrat ions result iiij,' from Losioiis of the
Spinal Cord in Monkeys. Rrain, Lonil.. vol. xv (lHit'2), ])|i. '^ir)-','2!t.
f I'atrick, Ilujjli T. I'eber aufsteipende Dejjreneration nacli totaler
Quelsehuntr des Hiickenniiirkes (Aiihan},' zu deni Aufsatze von Dr. Hruns :
Teller einen Fall von totaler traiiniatisclier /erst('iriinR des Hiickenniarkes,
etc.). Arch. f. Psychiat. ii. Xervcnkr., I?erl.. I?d. xxv (l«»:i). S. H:{1-H44 ;
also .1. Nerv. and Mont. Dis., X. V.. vol. sxiii (IHiMi), l.|>. H.VIOT.
GROUPING AND CHAINING TOGETHER OF NEURON KS. 595
ni
iKi- i
j
• (
i
f|
!
il
i
'"-
\
[.•[,; 151(7 _!),., r,.|icriititiii 1)1' (miwiin' tract iiliiivt' tlii' iiicdullii cililoiiKata. ^ AfUT
'll'. T. ratri.k, Anli. f. I'sycliial., Ikrl., B<1. xxv, is!t:5, S. 834 it s.'q.j
506
TriK NKIIVOUS SYSTHM.
;
in
._ ^:>:;^^-T-'r'-N
;-^ ■'
-n^'
Fi(i. ;«)H.— Ascciuliiiff (los.-ncration of the fiisciciiliis vciilin-lafiiiiHs (iowcrsi
alter lraii>Vfi-sc lisioii nf tlic luiliiaii ccnd at tlic level of 'I' vii. .Metliiid of
Marelii. (After A. H.ieiie. Arili. f. I'syeliiai. ii. Neiveiikr.. lierl,. liil
xxviii. lS!t(i. 'hif. ix. Fij-s. :i-il. I A, level (pf (leciissatin pyrainicliirn : ".
(iowei-s' Imiiille. H, level of deciissatii) letmiisconiiii : k. ( iowers' tract. ( '.
level of the iiif.rior half of the liiicleiis olivaris Inferior. I), level of the
.-iiilierior half of the niicleus olivari- inferior. K. level of the uenii iiiternnin
nulieis N. faeiali.s; </. (iowers' tract; /<. (U'fjeiierated area in corpus rcsti-
F. tviuisvcrsc section !it tlic li'Vcl iif the radix X. triuciiiiiii ; a,
1(1 iiilii Ilic liiKtk ; /), (idwcrs" liniiflli' al'lir tlic
(iowci-s liiiiKlli' Ix'iiiliiit,' aniiM
iiidk riiiinaliiiii. iimiiinu li.ick into tin- (■('icliclliiui. (J. traiisvcisi' scctinn at
the level iiC the inleriin- eiilliiiilu^ ; ", the iinrliim (pflioweis' Uiindle wliieli,
acccirdiiii; t^ IIik he. extneN farthest <'eri'tiral\vard.
I
f i
¥.
Ill I
f; !l
{:■!
tH^H f)
I ' '
M !i.
Ir,
Ht!
' ll
i
11
t
598
TIIK NKKVOUS SYSTKM.
Kisic'ii Russell * finds that in nmn the fihrcs of (Jowors' tnict
begin iis I'iir down as the third or fourth lunibiir segment. He
insists further that though there is marked " overlai)})ing" or
"mixing" of the efferent with the afferent tracts in the ventro-
lateral region of the cord, the main rejiresentation of the alferent
tract is internal to that of the efferent tract, that is to say,
(Jowers' tract is sepai^ated from the periphery of the cord by
efferent fibres.
In 18!)(i, Ilocho f was able in two buman eases to follow
the tract through various levels of the cord, medulla, jxtns,
and midbrain, and thence back througb the bracbiiini conjnnc-
tivum or medullare anterius into the cerebellum. The findings
in one of his cases are well illustrated in Fig. ;J!)S. In the second
of his eases he thought he could make out a decussation of the
fibres in the roof of the fourtli ventricle. Jt is evident, there-
fore, that Testut, Edinger, and Mott are correct in assuming
the existence of two direct tracts from the spinal cord to the
cerebellum, and it seems likely that, in the future, Flechsig's
tract will be known as the fasciculus spino-cerebellaris dorsalis
(or dorso-lateralis), and (iowers' tract as the fasciculus spino-
cerebellaris ventralis (or ventro-lateralis). ,
The cerebellar termination of (iowers' tract has been made
out also in human cases with Marchi's method by \. Solder J
and by Worotynski.*
The newer investigations make it appear that what we have
designated above as (iowers' tract consists of at least several
distinct neurone systems. The principal mass is the fasciculus
spino-cerebellaris ventro-lateralis, which goes through the In-acb-
ium conjunctivum or velum medullare anterius to terminate
in the cerebellum. This corresponds to the ventro-hiteral con-
junctival spino-cerebellar system of the Swiss and (Jermans, and
* Russell, J. S. R. Contrihulioiis to the Study of Some of the Afferent
and Etlerent Tracts in tlie Spinal ford. Brain, Lond., vol. xxi (1898), pp.
l-ir)-170.
t Ilochc, A. Uelier secundiire Dej:(cneration. spcciell dcs Gowers'schen
Biindels. nebst Renierkunfjen uelier das Vorhalten der Reflexe hei Coni-
pri'ssion dcs Riifkenniai'kcs. Arch. f. Psyehiat. u. Ncrvenkr., Berl., Bd.
xxviii (1806). S. .^j 10-14;!.
X V. S(")lder, F. Dcj,'enerirte Bahnrn ini Ilirnstaniine liei Fiiision dps
unteren (Vrvicalniarks. Xeurol. Centralhl.. Leipz., I?d. xvi (1897). S. :iO.S-;il3.
* Worolynski. B. Zni' Ijchrc von den secundilrt'ii Deg'eneratioMeii im
Rliekenmarke. Neurol, ('cntralhl.. l.eipz., Bd. xvi (1897). S. 1094-1097.
(iliOri'lNO AND CIIAININC} TOOETIIKU OF NKUKOXES. r^\)ij
might very well be culled the si/sfi'iiitt [ticiiroiiiiinii] spiniH-i're-
hrl/fire irnlnt-lntrrtilv roiijii/irfinilc. The rcsfurclu'S of Kdin-
ger,* Mott,t iiiid others miike it appear that several other neu-
rone systems exist, whose axoiu's take a similar course for at
least a long distance in the spinal cord and rhombencephalon.
Kdinger, in ISS!), from studies of myelinization, came to the
conclusion that many of the meduUatcd axones ascending in
the fasciculi [)r()i)rii of the ventral and latei'al funiculi arise
from cells of the dorsal column of gray nuitter in the opposite
side of the si)inal cord. The crossing of the axones, he be-
lieved, occurs jjartly behind the canalis centralis, i)artly in
front of it, by way of both the commissura grisea and the com-
nussura alba. He separated this crossed aseemling ventro-hit-
eral system from (iowers's tract.
The nu)st important observations in this connection are
those of Mott, who, experimenting on monkeys, studietl the
resulting degenerations by the method of Marchi. .Mott has
clearly distinguished, in addition to the (largely crossed) con-
junctival spino-cerebellar ;^,ystem, ( 1 ) a ventro-hvteral superior
spino-(|uadrigeminal system and {'i) a ventro-lateral spino-thala-
mic system.
The ventro-lateral spino-ciuadrigeminal system (or, as it
might very well be designated, the .s7/.vA'///(^ [iienroiiiritin] .sjji'no-
tjitatlrigetniindii rrufnt-htteride snpcrins) sends its axones, the
exact origin of which is still doubtful, upward in the sul)stantia
alba of the spinal cord, where they are situated at first in the
internal (central) of the three zones of white nuitter at the
region of exit of the ventral roots. I'assing up through the
ventro-lateral region of the cord, they ascend into the medulla
oblongata, where they are found among the other fibres which
represent the ventro-lateral portion of the continuation (in the
medulla) of the ventro-lateral funiculi of the cord. The tibres
Ji'
!i ■
H
* Ediiif^er, L. TohiT dio P'orlsL'tzuiijj (lor liiiitorcn IJiickeniiiarkswur-
zela ziiin (iehini. .Vimt. Aiiz., .IiMia. Md. iv (IHSit). S. l'21-t2S.
f Mutt, V. W. Ui'sults of Ilemiscctioii of the Spiiml Cord in ."Monkeys.
Phil. Tr., liOiul. (IHOl); also, Ascoiidinp: Dtu'i'ncnition. resulting from I^e-
sioiis of the S])iniil Cord in ^lonkeys. Uriiin, liOiid., vol. xv (1H02). pp. ^IT)-
22!) ; also. Experimental hKpiiry upon the AtTerent Tracts of the Cent nil
Nervous System of the Monkey. IhuL, vol. xviii (1H!I5), pp. 1-20; also, Die
zufiilirendon Kleinhirnhahnen des Rin-keninai-ks liei deni AU'en. Monatschr.
f. Psvchiat. u. Neurol., Herl., Hd. i (IHiiT). S. 1(»4-121.
I
'Mi'-'
r>()()
TIIK NKllVOUS SYSTKM.
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m- ""
iteii^
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'din .Loasa
StKf&HfefJ'
wliicli at first lie liitcral from tlic mu'lciis olivari.s inferior conio
hif^'iicr up to l)t' sitiuilt'd vt'iitro-liitcriilly from tiie miclcii.s (jli-
Viiris su])crior. W liilo the vc'iitro-lati-rul conjunctival spino-
ecrel)clhir system turns dorsalward, at a level correspoudin^jf to
the nervus tri<,'eniinus, just hehind the coUieulus inferior, so as
to i)ass lateral from the tractus spinalis nervi tri^emini into
the velum, the spiiio-(juadri<,feniinal system of Mott continues a
course ventro-medial from the tractus s])inalis nervi trigemini
aiul from the nuclei terminales nervi trigemini running mixed
with the handle of flhres which descends from the nucleus ru-
ber of the opposite side to the lateral funiculi. Accordingly,
the spino-tpiadrigeminal buiulle comes to lie dorsal from the
level of the nucleus olivaris superior and between tlie fibres^of
the lemniscus lateralis which here pass dorsalward. The fibres
of the spino-(|uadrigeminal system lie in the medial portion of
the lemniscus lateralis medial from the nucleus lemnisci lat-
eralis. At the level of the colliculus superior the spino-quadri-
geminal fibres become separated from the descending axones
from the opposite red nucleus, since the bundle of the lat-
ter, ventro-lateral from the nucleus ruber, has reached this
lateral position by ])assing from the nucleus ruber of the oppo-
site sjde through the decussatio tegmenti ventralis in the raphe
lateralward. The spino-(|uadrigeminal system, on tlie other
hand, turns medialward into the substantia grisea of the col-
liculus superior in order to terminate Ity end-ramifications in
among the perikaryons and dendrites of the neurone systems
situated there, mixing with similar end-ramifications from the
tractus opticus and from the auditory axones of the lateral lem-
luscus system.
.Mott's spino-thalamic fibre system (or, as it might be called,
si/sfrtii(( [tirK/'ottiiiim] .spino-thdhiinirKiu ir/i/ro-ld/rni/r) also
takes its origin in (lells in the gi-ay matter of the spimil cord,
but just in what regions and whether on the same or on the
opposite side, or both, does not seem clear. The medullated
axones ascend through the ventro-lateral region of the cord
mixed with those of the spino-(juadrigeminal system and to a
certain extent witli those of the conjunctival spino-cerebellar
system. In the medulla oblongata the course of tlie path is
the same as has been described above for the spino-quadrigemi-
nal system, and the fil)res of Motfs spino-thalamic system ap})ear
to be mixed, not only with those of his spino-quadrigeminal
• lllj
(llv'oriMNd AM) ('ll.\IN'IX<i T()(iKTIlKU oF NKliniNKS. r.dl
systoiii, l»iit, liko till' latter, iilso with the (k'sceiulin>i til)r('s
froin tlu' iiiidhrain to the spinal cord. At the level of the col-
liculiis su]>erior, as has ])e('ii iiieiitioued al)()ve, the descending,'
niethiUated axones Troni the re<l nucleus to the cord ln-conie
separated fn»m thn common hundle (in the medial i)art of the
lateral lemniscus), as do also the ascendinji^ 8pino-<|uadri<,'eminal
fibres. 'IMie meduUated axones of Mott's ascending spino-thala-
mic system, liowever, are continued with that portion of the
lemniscus lateralis which ffoes })ast the colliciilus inferior with-
out stoppinj; in it. Further on they become more or less mixed
with the medullated axones of the lemniscus medialis which
are scattered more or less ditTuscly in that re<j;ion of the te<f-
mentum which lies medial from the corpus ^eniculatum medi-
ale. It seems likely that the axones of the sjdno-thalamic
system enter the hilus thalami and terminate in the ventro-
hiteral rej^ion of the thalamus alonj; with the jirimnpal axones
of the lemniscus medialis (those derived from the cell l)odies in
the nucleus funiculi gracilis and the nucleus funiculi cuneati) .
and the axones from the cerebellum (by way of the hrachium
conjunctivum and red nucleus, to be described further on).
For further notes on ascendinj; (central-axone) s})ino-thala-
mic neurone systems, the reader is referred to the publications
of Mott,* Patrick,! von Snlder,| and Tschcrmak.«
Before leaving the subject of the fasciculus ventro-lateralis
superticialis ((iowersi) reference must be made (1) to the recent
publications of Uossolimo and {'i) to the findinfrs of Tschermak
coiu'crning an ascending vcntro-lateral restifornuil cerebellar
system.
Rossolimo, || in an article accompanied by seventeen illustra-
tions, describes his findings concerning secondary degenerations
in the region of (iowcrs' tract. lie employed the method of
Busch,''^ a modification of the method of Mardii, which pos-
sesses, he thinks, certain advantages over the latter procedure.
The patient, a girl of twelve years, had suffered from retropcri-
• Op. cif. f Op. cit. X V. Solder, P., op. cit,
• Tschermak, A. Ueber den centraleii Verlauf der aufstoigendcii lliii-
terstraiij^t)alinen iind dcrcii Bczieliungen zu den ISahnen iin VfU'dersciten-
strang. Arch. f. Anal. u. Physiol., Anat. Abth., Leipz. (18!»8), S. •^!)l-4()0.
11 Rossolimo, G. J. Ueber den eentralen Verlanf des (Jowers'sehen Blin-
dels. Nenrol. Centralbl.. Leipz., Bd. xvii (IHJtH). S. 9:5r)-!t4(l.
^ Biiseh, C. Neurol. Centralbl., Leipz., Bd. xvii (18'JH), S, 476.
t;^
<1(»2
TIIK NKUVors SYSTKM.
I'- ■' '
i
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1
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■
toiical sanoiiiii, with iiiiiltiplr mctiistasi's, tlicspiiiul conl liciiif,'
involved cliiclly in the lower tlioraeic and liunhar rejfioii. In
the ventro-lateral rej^ion lie found a very delinite doj^oneration,
wliicli on the wli(»le eorresitonded to the ))osition of (iowers'
tract in the spinal cord as well as in the medulla and poU'^.
A few of the de<fenefate(l lihres left the huiidle to entei' the
eorehelluni by way of the corpus restiforine. No lihres, accord-
in^' to Rossolinio, passed hy way of the hrachiuin conjunct ivutn
or velum medidlare antei'iiis into the cerehcUum. On the
other haiul, the fibres underijio a partial decussation in the
velum ami then run to three dilTcrent rejjions — (1) into the eol-
liculus inferior, ('i) into the substantia nijrra Soemmerintrii,and
(;J) into the trlobus pallidus of the nueleus lentiformis. Rosso-
linio concludes that his case is a sharp contradiction of tlu'
scries of results obtained by LoewiMit lial, Aiierbach, Mott, lloclie,
and others conccriiiiifi; the termination of (iowers's tract in the
cerebellum by way of the l)rachinni conjinietivnm and velum.
'I'liis I can not a^nu-e with. On the contrary, liossolinio's
studies are to be looked upon not as contradict injjf previous
knowledge, but as e.vtt'nding it in a nu)st desirable way. Uo.s-
solimo ai>pears not to have recognized tlie fact that (iowers's
tract can no longer be considered a morphological entity. It is
much rather a complex of iibre systems liy no means homolo-
gous with one another. We have seen above that it contains (!)
tlie medullated axones of the systerna neuronicum spino-cerebel-
lare ventro-laterale conjunctivale, (2) the medullated axones of
the systerna neuronicum spino-tiiiadrigeminum snperius, and (:>)
the medullated axones of the systema neuroniciim spitio-thalami-
cuni. We shall see in a moment from Tscherniak's stiulies that
(lowers' tract also contains (+) a systema neuronicum spiiio-
cerebellare ventrolaterale restiformale. It appears to me that
the correct interin'etation to put n])on Rossolimo's studit's is the
following: From the lower i)ortion of the spinal cord there
ascend medullated fibres in the course of (Towers' tract mixed
with the fibi'es of the neurone systems above mentioned. The
termination of these fibres is partly in the cerebellum (corre-
s})onding to Tschermak's ventro-lateral restiformal sjiino-cereliel-
lar system), l)ut chiefly in regions hitherto not known as receiv-
ing fibres of (Jowers' tract — ''iz., the collicidus inferior of the
corpora f|ua(lrigeniina, the substantia nigra, and the nucleus
lentiformis. If Rossolimo's observations and the interpretation
(JROriMNCi ANlt CllAININM} T<»(iKTII Kl! oK NKntoNKS. coi!
here siii,'^'('str(l Ik- (•••itccI, wc sluill liiiVi' to j)iisli the analysis nf
lilt' coiuiilt'X dl" illtrt' systems rfpit'si'iitcd l)y (inwcrs' tract
still fiirtluT than that fiivcn above, ami add (A) a systema iieii-
nmicnni s|)iii(M|uadrijf('miiuim iiitVriiis, (ti) a systcma iiciiroiii-
ciim spiiio-pcduiicularc (ad sid)staiitiam iiiirram), and (',) a sys-
tt'iua mniroiiiciim spiiio-lciitifni'mali'.
Tscdicrmak * lias (U'scrihcd at some Ifiijrili a vfiitro-latt-ral
spiiKMcrt'ltcllar rcstiformal neurone system. f After seetion of
the ventro-lateral funiculi at the level of the nuelei of the dor-
sal fuTiiculi, he found hy Marehi's method dej^enerated tihres
passiny dorsalward, in part at least, from therej^ion now usually
desifjmited as that of (lowers' tract in the medulla. Tliese
tihroH consist of two jfroups : (I) tihres at ilrst lyiiifj in tlm ti.ssu-
ral part of tiie remains of the ventral fnnicnlns, ami farther on
coniiuf,' to pass lateralward dorsal from tlu' ri'uuiins of tlu' ventral
herns, and still higher dorsal from the nucleus olivaris inferior,
and (•.*) tihres which join the former — viz., transverse fibres
situute(' at iirst on tho medial side of the nucleus funiculi latera-
lis as well as latero-dorsal from the nucleus olivaris inferior. All
tliese (ihres ( Fihrc /nnisrrrsd/rs i/nrsiHilirdfi's r/ i/iirsd-niir/i'in'i's)
become aj^f^re^atetl into a thick transverse liumile dor.sal from
the nucleus funiculi lateralis, in which prol)al)ly terminate
numerous bramdies of ascemlinj^ tihres from the sj)inal cord;
the bundle arrives in the white matter at the ventral auffle of
the traotus spinalis nervi tri<:emini. Tiie fibres under con-
sideration next pass, looplike, dorsalward and arrive, by way of
the medial portion of the tan<];ential fibre-coverinif of the trac-
tus spinalis m-rvi tri<femini, into the ventral part of the corpus
restifornu'. 'Pschi'miak thinks that the fibres pass by way of
the lateral bundle, of the two bundles into which the corpus
restiforme divides, into the vermis superior, probably to both
sides of the middle line. It is, as Tschernuik renuirks, rather,
interestinj; to note that whereas Patrick describes a few fibres of
the direct dorso-lateral cerel)ellar tract which, instead of enteriuf;
the cerebellum by way of the corpus restiforme, pass on to
enter that organ higher up by way of the ventro-lateral conjunc-
tival spiTio-cere])ellar system, these findings make it appear that
an exact counterpart exists in these fibres of the ventro-lateral
■ft.
* O/,. rit.
f His aitfsteiijenib'.'< nitti'vnlitti'nih's irKlifonnales Cerebelhirsystem.
4(1
h;.i
(;o4
THE NKUVOUS SYSTEM.
spiuo-ceri'lK'llar tract wliich, lower down than their fcllowH, puas
into the cerehelluni, tiiiviii^ the shctrt cut by way of the c(trj>ii8
restiforinc. I take it that the few tibre« observed by HoHsolinio,
above referred to, passing from (lowers' tract into the corpus
restifornie, beh)ng to the same neurone system us that of
'I'srhcrinak Iierc mentioned. It seems likely, too, that TschtT-
mak's system is identical with the third of the three ascend-
ing spino-cerebullar systems of Auerbach above referred to.
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1 F«soiculu-< Inli'mlis nropriuB and ilK cmilinu-
I '^lion in the mcdiilU olil<)ii|;ata(ttbri'» (■ijiiiiMt- L _^ Kanciralus itra(ill» iHolln.
' "linu reflex fielils ol the uieiliilla nhlonuata and
'the lateral fiiniruli of the spinal eoril .
I 1 Kasciciil' ceTehro-Bi)inales (pyramidal tractH
' l-')Mi pallium to spinal cord).
LZI
1 FuciculuH Bulno-cerebKlUrU (ior8.)-l»U'raIw
(»Urecldor»o-lKteral ci-rebeUar tract of FI«:h-
I »«»)■
I KiwciculuM ventralis iir<n»riuH tc.ntiiniouK in
the inedulU nblonjifaU with tlie fa.soirulii9
f innieitudtiiuHs iimdialis).
i Ka^'iriihitt eracilif) (Uurdacht); in the Itim-
( bar cord FUsrhaiif 'a oval bundle.
^ ribra' olivo-ctirebellareit and other (ibres in
the CLTjiuit reutifornie i rndtx deacendt'DH N.
( veBtibtiU; stratum interollvare lemnisc).
\ Subataiitia ^rist-a ; the black itipple repre-
{ Ht>nts thd tractiu BplnaMa N , trlgeirdni.
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>"t'i:.Ai.- \ \oN-i: (ri x 1 u! rr,' M.) M.ri.oxi: svsi'KAi.s r\ tut:
I.) i'Hiii'Ki' "i;i.K(M V !i-i'.;n ii:.i> I)! I'll i; '^I'j \ \L ctH!!).
,;i;il liii;(,'iT nviir \'hi '-V'-tr:iis--liili;i>('uii)Ciitul ;ir iiitf.niinwiii! Jlss(^-
i.iii M\iin«-i'-— !'c!-ilv;iryMii-^ !Mil >lr!i.ii'ii,'v. — rmt'imcii''. licU'i'-iin'rio.
iii;";it>-ri. nitric iii'un.iir-- -.i m ii,-s ami i f'll;iicr;ils-- I'ln' iiU'Tiil
' .■■\z hivi'f— lis v.uini! .iii'l •i..r-;vl [i!trt.-5--i'.iii..i!i"^ in \\\<- rh.iiiiiii'ii-
■' 'I'lii loiiltiiui.ii- wild U'l' iV,-''n lilt [iMprii 'if I ht^ siuiiiii >;'.oni— -'^t,l•
llMl[l;.• viiir fiTfi.c.-i': s\- 1(111 Ml ;!,,• in-ci'-iilii-. )i.iij.',ini'l!j ,iii.- !iit(li!i)i'-
■■■■lui:\'" iiiHul'?r.s t'T u->'''m!;'.!_; iifitl .!i •i.'i'jitlMitf n.v. •!!(-, in iI.-m'
• •/ 1 I'lif I"'')'.!.!-;!! s,Mis(ir\ I 'U.'iiici ji^ti pal li.- rorri-,--])(iiiilit:i:
■ oiiL-.s ihc 1 i!l lioiii''.- I'l' >A !i!i''. nro '•!: uiibi'ii in \\\>^ f.n'iiv
of tiji.- .(ir..;. Llif .txt'iu.'S iicl(;i!iL' 1^ ii»;i'''- •ip ttn.- f;iscici;li
r i i f thv vciiiiiil, Iitt(;'.-;il. aijt! tltij-iil fu.i;.':ii (.1' liu' n!.ili»
ill tlif i-ord, ii;i\"t' liri'li i.'ic i.!ii> li. .', ii;<:''i suul',. Imii ,\<
V |i!irti;il ;ilii.i Ulisiit i' !';ift"irA !M!''irP.;!< ! n: <-i;i.-''r!iiliv l \\v\u
■ 1 t.'.ilr.* 'fii" f';i>i'i'-'.il! ]iiti,,i ;: c,,' ;('.. ,. '•;.. inatfr roii^iiii
if flioi-foi- aihi loiiut'i- I'.iiii.i'i • >s^.t. i.v.s, !!•.. II a-(ini!ii,;.: ami
i''.iil^. ' ri)r-;:i'(i ari'l iirnro.-: i-i!, l":;;- -.'ikh ' ;■■ illn<-- .tpjii-ar ti
;> ami l«)\vn (.•K)sc \n il,,' -jrr, > i'.-i- j.i t • Uu- ]oiiir»'r lilin.-i
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it Ml"' I U'"l!ill|i.- . I hi \! .V (■/■•)( :/r,''i., ■ lOi'liliI'- li..' f.'lM.ii ll.il-. ':lf-
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1 :l |itiiliti:i iif l-''li\'!iiii;'.. ■i-r ,,• ,.•,.•'. S> ilr'ii.sfrtini/zoiir. i'ln
• r 1 i' t'li' ' 'iltii'. ! "v;. .lit-; I i,f ill. -i(i , iiii iti4 li\ .'f iir liiyi'iciila'-
'iiiii'i.'ias 1,'i't, .;/.•. -ii. ''ir<< i it/r.-^ ,. V:/'"'i'ri:'l. umIci' lip tl-i
I1i';(<r"hrl!i''iii\l' ' iv •'\m' .11- r.ii|> I •'■ ';: .• | |(.|'n(ls i i'l l,. !''•'.' '. 'I'f.'
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. i ■ ■
CIIAPTEK XLU.
ON CKXTUAL-AXOXK (cKXTKI I'KTAL) XKIKOXK SYSTKMS IX TUK
FASCK TLI I'KOI'KII OK (iKOl' XD-IUXDLKS OK TIIK Sl'IXAL (OKI).
Shorter aiul longer iieur(>iie systems — Iiitersegineiital or intenuincial asso-
fialioii axoiies — Perikaryons and dendrites — 'I'mitonieric, lieteroiuerie,
and hecateroinerie neurones — Axones and eollaterals — The hiteral
limit inf,' layer — Its ventral and dorsal jiarts — Hiindles in the rlioinben-
eeiihaloii continuous with the fascieidi pmprii of the spinal cord — The
aseending spino-eerebral system in the fasciculus loiigitudinalis medialis
— {{elative numbers of ascending and desceiuHng axones in these
bundles.
{(!(/ d) The central sensory coiuluetiou paths corresimndiug
to neurones the cell bodies of which are situated in the gray
matter of the cord, the axones helping to make up the fasciculi
proprii of the ventral, lateral, and dorsal funiculi of the white
matter of the cord, have been the object of much study, but as
yet only partial and unsatisfactory infornuition concerning them
is available.* The fasciculi proprii of the white matter contain
fibres of shorter and longer neurone systems, both ascending and
descending, crossed and uncrossed. The shorter fibres appear to
run up aiul down close to the gray substance ; the longei fibres
tend to occupy areas nearer the periphery of the cord. The neu-
* The fasciculus ventralis proprius corresponds to the Vordfrxfraiif/i/nnid-
J('i »(/('/ of the (icrmans ; i\mr Sfifi'iislnnu/renlc includes the fascicidus lat-
eralis pro])rius and Gowers' tract. Thus, Flcchsig (Leitiingsbahnen, S. 299
fF.) describes the Spifeusfriingrcfite as being made up of two territories:
(1) the rnrdi'n' (jemlscltti' SeiteuKfrauf/zone. and (2) the Keillirhe Grcnzsrhicht
der (fniiipn Siilisfdm. As von Hechterew showed, (lowers' bundle corre-
sjionds to a portion of PTechsig's vordirc (jeniischfe Seiteiistrnnj/zone. The
remainder of the latter, together with the lateral limiting layer or fasciculus
Ifiicralis liniilans {.ipiflir/ii' (Ironzsrhirht der (/niiicii Siihsliiiiz). nuike up the
Siifi't:xtrn>ig(jni)idli"nidt I or the fasciculus lateralis pro|)rius (Fig. n99). The
(ieruuuis often speak of the fasciculus ventralis et lateralis proprius together
as the Vvrderseiti'UHlraiiyresle.
(505
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ooo
THE NERVOUS SYSTEM.
roiR's c'oncerntM! serve to comu'ct sof^niicnts of various levels with
OIK! another, and their axones are aeeordingly sometimes referred
to as " intersegmental " or ^ internuneial " axones or as those of
"• loiiffitudinal association illn'es." Tiie shortest ones connect
segments immediately adjacent to one another; the longer ones
may c(>n»ioct widely separated levels of the spinal cord and
rhomhencephalon, or may even hring the spinal cord into
relation with the mesenci-piialon and dieucephalon. There is
much reason to l)elieve that many of these neurones, es])ecially
tiiose with ascending axones the myelin sheaths of which accord-
ingly undergo secondary ascending degeneration after lesion,
have to do witii the carrying of centripetal impulses toward the
higher centres, and they are accordingly a])proi)riately consid-
ered here.
'J'iie perikaryons and dendrites of these neurones have heen
studied especially by Kamon y C'ajal, von Kolliker, van (Jehuchten,
and von Leniiossek. Tliose which send axones to the fasciculus
ventralis propriiis are situated (1) in the most medial part of the
ventral horn {KiniiniissKri'iuirnppc o^ \o\\ Leidiossek), and {'i) in
the ventral and mid<lle parts of the gray substance. Those which
send axones to the fasciculus lateralis proprius are situiited in
the middle regions of the gray substance and iii the dorsal horns
as far back as the substantia gelatinosa of Kolando. Those
which send axones to the fasciculus dorsalis proi)rius (endoge-
nous fibresof the dorsal funiculi) are but few in lunnber, aiul ap-
pear to be situate<l in the gray tnatter of the dorsal horn (Fig.
400). The axones of these various cells pass partly to the white
matter of the same side (those of tautonu'ric neurones, van (ie-
huchten), partly to the white matter of tiiv opi)osite side (those
of hett'romeric neurones), and occasioiuilly, after divison, to the
white matter of both sides (those of hecateromeric neurones).
The calibre of the axone sometimes increases at a distance from
the cell body. In the white jmitter an axone often divi(le> into
an ascending and a descending limb. Numerous collaterals are
given off into the gray sid)stan('e, so that a given neurone may
affect not oidy the gray matter of the segment in which its axone
terminates, but also, by means of ( ollaterals, the gray matter of
intervening segments. The arrangement of the wiiole mechan-
ism here under consideration seems to be that especially adapted
for co-ordinating the activities of the gray nuitter of dilTerent
levels. In so far as it is concerned in mediating the comluction
I .i
1 i
(iROUPlNG AND CUAININO TOGETIIEIi OF NEURONES. (507
m
i
it
H
li
Fig. 400. - Tautoiiioric, liptproiiicric. iiiid licciitcroiiu'ric ncuvoncs as rcvciilcd by
(iiilKi's iiu'tliiiil ill till' iiai's liiiiilialis III' llic liiiiiiaii s|iiiial riu'il. Coiiiliiiicd
IVoiii a iiiiniliir uf prrpanitioii.s taki'ii IVdiii a liiiiiiaii iiiiliryii 150 im. loiif;.
Till' lowiT iiiiiliir iiiiiioiics. till' iiiiiiiiiissiiial luiiriiiirs. tlir iiriikaryniis of
wliii-ii ail' sitiiatiil in (lie vciitnniudial |iait nl' tlii' viiitral lioiii. ami tlic
cliliiliaxiilifs (if till' slllistaiilia jiiisra liavr imt lircn rcpri'Sfiitiil. '.M'tirM.
von lii'iilidssi'k. Dir rriiicri' iiaii ilrs Ni'rvi'iisy>ti'iiis. rtr.. II. Ailll.. licrl..
IWI"), 'lal'. iv. ) /. .', .;. f, taiitiimcric iifiiniius. Ilif ]icrikaiyiiiis nl' wliii'li art'
sitiiati'il ill tilt' iiiiililli' /.line of the snlistaiitia fiiisea. tliiir axiini'S passiiit; tn
till' vi'ntral nr lati ral rmiinilii.s. wlicrc tlii'y assinni' a Iniijiitiiiliiial (lirrctimi :
0, ni'iiiipni'. with pcrikaryiin in lalci-iil n'^'iun of ^I'ay niatli r and axuiic
passiiifj vriilrahvan! to liil'nri'atc. the linilis iiF liirnrratimi riiti'viiiK. oiii' of
tlii'iii till' vintial t'iiiiiiiilii>. till' (itliiT till' vi'iitral riininiissiiii' ; fi, lunrdiu'
situated in lateral part i it' ^I'ay niattir sendiiif; axniie tn lateral rnnii'iiln> ;
7. >'. .''. /", tiiipiips III' nerve eells in niiddle re^inii seiidiiif; axniies to veiitnil
or lateral t'linienliis; //, /..'. /.;. /.}. /.■;, /;. iierikaryons in dor.sil lioni semiiiiK
axiiiu's to lateral rmiiiiilus: /'i', deiidraxnne ; Z.^'. neurone transitional in type
lietweeii an inaxone and a deiiili-axoiie. the axiineii liil'iireatinj; and liranch-
inu nianiloldly in the ;;ray matter, hut semliin; a hraneh to the siihslantiii
allia ; /.'', perikaryon in ilorsil eoniinis-ure ; .'", perikaryon in suhstantiil
aiha ; .-'/. .■'.•', -■'..', ei'lls just ventral to suhstantia };elatiiios.i ; .'(. .'-'i. /'<'. neurones
seiidiiij; axoiies to ventral luniiulus; .',', neurones seniliny axone to lateriil
I'unirnlus; JS, J!), Ml. ,tl. neurones in niiddle reyioii si n linn axoiies to ven-
tral fiinieuliis; .ij, .i.!. .<}, .i'l, .lH. -Hi, .'id. neurones in dorsal horn whose axoiies
fill to the latenil funii'illus: .(,", perikaryon in suhstantia alha I'orniatiu
retieularis> ; .i^, ',". )/. ->-'• !••'• nt'rve cells in dorsal part of dor.sal horn, soiiio
of whii'li send axoiies to the dorsal funiculi.
■••! 1
i ;■/!
1.
\
ii
SI
OOS
TIIK NHRVOUS SYSTEM.
of inipulsos to tlu' liifilicr ciMitrcs coiKHTiU'd in sonsatioii, the
lueohiiiusin must, for the most part, be h)oke(l upon as a con-
duction path of many relays, tluit is, of nniny su})erimposc(l
neurones, the impulses which travel alonj;; it passinjj; alter-
nately from <fvny matter to white matter and from white
matter to j,'ray matter over and over again as the lu'ural axis
is ascended.
The so-called lateral limiting layer, or fasciculus lateralis
limitans,* was first described by Flechsig on the ground of
studies of myelinization in LSili. By it he meant the j)ortion
of the lateral funiculus, close to the substantia grisea (F. 1. 1. in
Fig. ;}!II»). Flechsig's ideas of the origin of the fibres of this
lateral limiting layer were vague, although he felt sure that
it represented a complex of fibres of different sorts. The
area has been further ditt'erentiated by von Bechterew and by
Bruce.
\'on Bechterew f states that the fibres of the lateral limiting
layer do not have their origin in iibres of the dorsal roots, since
this layer does not degenerate when the dorsal roots are injured.
Nor do the fibres of the layer arise from the cells of the nucleus
dorsalis, for though the axoiu>s from the nucleus dorsalis run
through the fasciculus lateralis limitans on their way to the
dorso-latend periphery of the cord, they do TU)t turn to run
longitudimdly lu^ar the gray su])stance.
From the study of developing spiiud cords von Bechterew has
been able to divide the lateral limiting layer into (1) a more
ventral portion which is medullated early, ami ('i) a more dorsal
portion whicli is medullated later. 'I'he latter he has designated
"the medial bundle of the lateral funiculus." J This buiulle
lies Just lateral from the substantia grisea, dorsalward from tlie
colummi grisea lateralis, and tlius occupies a })art of the s])ace
between the fasciculus ccrebro-spinalis lateralis and the sub-
stantia grisea. Its lu'oader ventral extremity (as seen in cross
section) lies in the angle between the ventral and dorsal liorjis.
The topographical relations, however, vary somewhat at differ-
ent levels. Von Bechterew believes that his " medial bundle " is
* Die fieit/iclie (frenzschirfif di'r graueu Suhstnnz of P^lcelisig.
f VDii RoclittTPW, \V. Die Lcitiiiigsljiilinen im (idiirii uiid Hiickoiiiiuirk,
Leijiz. (1804). — UohiT das beson.iore, incdiale Miindcl der SfittMi.stfiinge.
Xeurnl. (V'litralhl., Lcipz.. Md. xvi (1897). S. 680-fi8!>.
X Mi'diales Si'itenstranijhumtel of von Bechterew.
OKori'IXG AND CHAININC} T<HiKTFIKR <»!•' XErUON'KS. r,()<«
composed of sliort modulliitcd iixoiu-s, wliich uri.si' from cflls in
the dorsal horius. The more ventral part of the lateral limiting
layer, v<ni Mcchterew hclicves, is made uj) of the niedullatecl
axones of cells situated in the ventral horns.
An interesting and im]»ortant extension of our knowledge
in this eonnection has heen furnished hy Hrnce, of Kdinhurgh.*
This observer, studying a case of amyotrophic^ lateral sclerosis,
found i)artial degeiu'ration of the ventral part of the lateral
limiting layer along with degeneration of the ventral liorns anil
of the fasciculus cerebro-spinalis lateralis. The dorsal part of
the lateral limiting layer (von Hechterew's "medial bundle")
was intact, as was also the gray matter of the dorsal horn. It
seems likely, therefore, that the lihres of the ventral part of tlie
lateral limiting layer have their origin in cells of the ventral
horn. In speaking or writing of the latend limiting layer, or
fasciculus lateralis limitans, care should therefore be taken to
mention whether one is referring to its pars thirxdUi^, its p(ir!<
vetiini/is, or both.
The fasciculi proprii are largest in volume in the iutumes-
centiiv. In the thoracic region of the cord they are relatively
snuill.
The continuation of these paths upward in the medulla and
pons has been carefully studied by Flechsig,t von Hccliterew,J
Edinger, and Held.* According to von lieehterew, the rela-
tions can be easily made out in hunum fcetuses 25 to '^7 cm.
long, when but few tracts are nuMluUated in the rhomb-
encephalon. Indeetl the fasciculi proprii of the cord are
among the earliest parts of the substantia alba to become med-
itllated. The results at which he has arrived may be briefly
sumnu'd up as follows : The tibres of the ventral and lat-
eral fasciculi go over into the formatio reticularis. The
* Hrucc, A. D'lin faisceivii sprcial ile la zone luterale de la moelle epini-
5ri". Rev. noitrol., Par., t. iv (IMOC)). No. 2!?. pp. OOS-TdO: also. On a Special
Tract in tlic Lateral Liniilinj,' Layer of the .Spinal C\)rd. Scot. M. and .S. J,,
Kdinb.. vol. i (1S97). X... 1.
+ Op. n't.
I von Hecliterew, \V. T'el)er ilie Lanj^sfaserziiEre der Formatio reticu-
laris niedullii' oblonj;;ata> et pontis. Xeurol. f'eiitralhl.. Md. iv (ISS')), .S,
;!;!7-:?46.
** iicld, IL Die Bezicliunpen des Vorderseitensrranires zu Mittel- utid
Iliiiterldrn. Abliandl. der niiitli. phys. ("1. der K. Sachs. (Jesellseh. d.
Wi.ssensch., Hd. xviii, X... (i. Leipzig; (lMiV2).
ill
I. ii'
ill
r;!.
I: I
\
\
I,
I'
t;i(*
TIIK NKU'VOI S SVsrK.M.
liliri's III' ||i(> rjisi'iciiliis vciilrjilis |H(i|iriiis, lo;;cl lu-r witli ii lur^ro
Irjicl (if llidsf 111' llic I'fisciciiliis liilcnilis propriiis, <^,> oxer
A'f'y
rr, - I
"■'"" ill
'/rrrn - 1 il;i!J«,J
/'///(• .
no/ft • ,':'k4f-
yr.r>' g-T*
iMi; tOI. A. Ii;msv<'i>c section tlinilliili \\w pnstciioi li:ilf,,r thr |Km>- Tli.' Irll
li:ill 111 llir illusinitiim .•orn's|Miiiils lolhc niil.i-ii.r, ihr liulil IimII' (mIIiiihis-
Iriior iM.ilioii ■>! Ill,' pons, i AlU r W. \uii l!,, lu.ivw, 1S«I|, s,,iiii'wli:it nio.li-
lU'.l.i .\>«.c,.v.. nii.'l.iis.rnlriilissnpciior; .Vc././.. iinrlciis l.ninisci l.il.Tiilis ■
AH.O..V.. nn.l.ii.-. ohviiiis siip.rior ; .V»./).. .mclci ponlis; Su.r t mi.l.us
Muiihiiis l.'fjiiuiiti ; AM., r.iilix N. triK.>niini ; H.iI.ii. W. \-m\\\ (Icsr.ii.lnis
(i|{<H'l'IN(J ANI> CIIAINlNd 'I'OOKTII Kl! (»F NI':riM)NI':S. (;| |
ll
ir(iii;,'li II iiiiirktMl fiirvf (lorHiilwiinl nnicHi'dinliM^' t<» iIk
(•oiirHc ol I he criit nil ciiiiii
I, iiilu III
i' H(H'iillr(l " tiK'diiil lii'lil
iiml inid llic ikIJiiccmI it^^muum of t lie " liilcnil licld " of tin- I'ur-
Miiilii) rcliciiliiris (I'ijf. 101). Tlir iildcH of lli<> iimihI doi.si.i |i(,r-
liuii (if I lie rnsririiliis liilcnilis |»r«i|iriii.s l»cc(»riM' sipiinilid I'ldMi
llir (itlicr iihi'cs iiinl run iis a (liHtiiicI hiiiKJIc nn ||ir liilitiil
|»fi-i|»li«TV *>\' tlic iiii'(|iillii. Tlicy Clin lie I'olliiwi'il hy llic ciiiliry-
»ilo;,'ic;il iiiclliud only ns I'lir iis I lie ,sii|M'rior oliviiry coiiipli-x,
ii!
I iiiij,iii(i|iliiilirii ) iHivi h JKitiiiiii ; N/.i/i.c, sliiilimi mi iw inl rule. Ilnl-
/.;. liliirs cil' III!' li'iiiiiiM'lls nil 1 1 hi I is |iri liiJIijiiM III III!' iilirlrlis riliijiiil
i riiiM'iili :
/(), snillrii li I Ills ill llir liiiiiiisriis iiirili;ilis ; //, rl^;i I' siiil Iflid liliiis
ihirli iliM'liiji hilr ill III!' hilriMJ lii 111 iil' llii- I'm unit in iiliiiilm is ; l:i, liin-
IIIHIIIS
iIi'I'mIis
J ■-//.,
/", (ilinv
ll
niirli'lls rilliirilll i^ini'llls ;
iiiiiiisMis iiiiiliiijis 111 iMiiiiiliiin in
liluis ri'iiiii llii n).;iiiii III ihr I'lillii'iijii
III llii' lillilills lilirilllllis lijjIiHIili :iiiil In Ihr pnMs. I iiilil
riisrii'illiis ii'iilr:ilis liniiiriili i milinlr lliiiiliiiilinliii ) \ '{, liln
s mriiinr
lilll'lS III'
IS llilsvill^ |,y
llic rnjilir riiilii llii' llllriri jiiililis In Ihr rnmiiilin 1 1| irii In I is Ulisiii ; .;s, liliri
ll llir spl
Mill lilMlillr I Mill I'll llir
I'l'W ) III' I III' lii'Mrliilliii |inii|is
I'l'irill lillliillrs ill llii' lii'MrliilMil i niijlllirl i Mini. lUii
liiiliiiHirs I |i\ I'iiniiihili'sl ; ./'i, lilii'i'S nl' ini'iliiil sin
nil iliillis III! nintni' iillrli'i ill' cri'i'lil M I lirI'Vi
ll
ri'l'clil'nrnl
iltllilli
; ;.';, ,;,'*, j,; ilif.
I'llsrirllli InllKi-
I' in ll InliisriiH
('<. (ililis nl 11 iiliiiil liiiiiillrnr
liilllll jinnlis; :,(l, riniitiil rrl'i'lil'nniiiirii|iiinliil piil li ; .'i /. Ii'iii|inl ripiliil
ii'n|inlll:il jiiilli. Iliivii- !>, rilsrirllllls Inll^il III! iniil is niiiliii lis ; ,S',
lilnrs wliirli l'i'|ilrsrlil llir |iii1iliil rniil iniiiil inn nl' llii I'^im iiiilii-, |;ili i^lis |ir
pliils III' llir spiiiiil rnril ; }'.', rniiilii issii lii I liiiiiillr l.viii^ M nl 111 I wii nl I'lnin Ijir
lii'Mrliinni rnnjiinrtiviini.
I!, Innisvrrsi' srilinii llimii^^li tlir Iniiiii sliin ; Iim I nl' |ii'iliiiii iili riri-
liri. Till' ri^lit liiill' illiisl iiilrs llir IimI nl Ihr rnllirnliis inririni'. Ihr.
Icll liilU'lhill III' llir rnlliillliis Mi|nlinr. i.M'dr W. villi I'.i I liliiivv. |Hi»i,
soinrwlllll liinililii'il. I I'/i'. :i<|lir<lnrl Ms nirlili ; r.i/./ii.. nil pii'-. ^iliirlilii'
ii:iniliiilliili' ; ('..s.. riilllriillls sliiiiiinr ; .V./l',
llllii liirillMir
rndix N. I inrhliiiiis ;
Cm., rnrjiiis i
','».(■, /'.. lilli-lilis rnlliriili i iil'i rinris ; Xii.l'.l.
rjriiH I'Msririili Iniiiil ml iiiMlis niiil i;i I is m niirhiis rnnmiissiini' iinslrrinri.H
(<.//!
Oiiiliiiiiiiliiriiisl.irii lit' |)iiiksrlir \\ ilsrii I ; Ac././., Min I'lrlilr
irw s rill-
pus fun'ithitifninitf nt
'nniiiiiiiiiithis III' Min !!i rhiiiiw
A».
Xii.l.s., nnrlrllS lillriillis .sll|iirinr nl' l''lirhsin ' niii-lr
linrlrils riilii r
, ///, nilrlills iii'ivi nrillniiinliiiii ;
^iilislMiiliii iii(;iii ; Sl.iir.i'., .slniliiiii (.'lisriini
(•(•nirilli'. li'iil I'.I. liluis 111' liliinisrlls lillrinlis wllirli cnltr rnllirnliis in-
ri'i'ini". "', lilircs III' hiMrhiiini i|iiMilriui'ininiini iiil'iriiis I'lniii Ihr rnlliriilii.s
lllrrinr III' (lir siinir :inil nl' llii- njijinsili- siili •, /.■', liluis nl' tin- lilnilisriis
IIICliiMlis
nri;;ni
ilin^inllir inn hiis I'liniriili riint'iili ; /.;', iihris nl' Ilii- li'in-
llisrils nii'iliiilis i^niiii; In I III' riir|Hii'M i|ii;iili i({i niiliii ; 10 , sciilli'lril III Mil I Irs nf
Ihr Iriniiisriis whii'li nn nvrr ililn Ilii' liMsis iiiilil liillli ; /,', irKinli nl' Ihr snil-
liTiil lilil'i'S l;ilr In ili'Viliiji I nf (hi' rniniillin III iiil lill'is. Vvlliiii /(/, (ilili'H
III' liliinisrlls iiiiiliiilis riniii Ihr iiiiiliiis rnniriili ^I'iirilis; 'jiS. Ilhi'is riniii Die
inirlills rnlliilili ililiriniis In llii' Ihiihiinlis iiiri'iililillK In Villi lii rlilr.'i'W ) ;
.'i'l', lilil'i'S riiilll llii' rnllirlllns sll |ii'iini' In l.'ir irlilillll riirli'\. I'iiihl .',!>, I,',i,
lilircs III' llir lii'Mi'liiiii
iinrljviini liil'ni'i' lliiir iiil riiiiri' iiiln till' fci!.
n rniii
;>'. liluis riniii llii' lid niii'li'ils In till, ninliiis Iciil irnrinis, tin
lli,'il;iiniis. Mini Ihi'ii tiIh'mI i-nilcx ' Ihi'si'iiii' tin' niiliiil inns nl' t In- nil niiilrlis* ;
.■'.->. lilil'i'S III' till' rilsrirllllls i-rlll I'illis lri.'liiinl i ' I'ciiliiili' lliniliriiliiiliii . liiivii —
.'', I'Msririiliis Inimitiiiliniilis ini'ilinlis ; .;/, lilins nf I lir iIhi'smI jimi'I nC thi'i'iilii-
iiiissiii'ii |insliriiir; ..'/', lilins nC I hi' vinlnil |i:ii'l nl' I In rnininissiini piisliiini",
S. rilsrirllllls I'i'triillrxiis Mi'yiiiil i ; ..'.', Ciisiiriiliis I liiilMinnniMiiiiiiilhiris \'ir(|
(rA'/.yii 1 ; .'V, tiisririiliis priliiiiriilnniiiinniilliiris puis Imsiliiiis f iirilniniiliis
corpiiris liiiiliiiiiilhiiis - ; .7,s, lilms riniii Ihi' siilisl;iiili;i t;iisi'ii nC I lir rnllifilllis
Sliprl-inl' In llii' l'ri,'iiili nl' I hi' niH'li Us I'lllur nl' I In- nppnsitr sidi'. ///"( — .{,
fiisririlli liinuilniliii:ilis py niniiiliili's i ; .■;", tilil'i's nf frniitiil ci'i'ihrncnrti-
I'lipiiiit.'il piilh I mii'iIImI liunillr in liiisis |ii'iliiiirilli i ; -'it, lilins nf nn-ipitn-
ti'lll|>iirill ri'l-rliriirni'lii'iipniiliil piilh ImIiI'mI liilliilli' ill hiisis piiluiirlili ; .^H,
lilil'i'S nf thr nri'i'Ssniv lilinilli' nf llir Irinliisrils ; ./',', lilnrs rnlinrrl illU till;
Sllhstiilili:! lii^l'M with Ihr rrl'rhl'Ml hrlliisplirrrs.
I ,t
■il
!
1
)F(T
t;iii
TlIK NKUVOl'S SYSTKM.
i; I
|in'.' m
I
Ml!
i
'.
1
where von liecliterew thinks they arc internii»tei] in the niielei
of the e()rj)us trapezoiih-uin.*
At a h'vel eoiTcspondinf,' to ahout the nii(hi[e of the inferior
olive, the tihres from the fuscieuliis ventralis (jroprius, to^^ether
Vui. 402. — Scliciiiiitic section tliniiijjli tlic iiicdiiUa oMiPii^fata at tlic level ol' the
routs 111' the N. vat,'"s and N. Iiyiiiitiliissiis. (Al'teiW. von liecliterew. Die
LeitiinKslialinen ini (iehirn iiu<l liiiekeninark, Deutsi-h von \l. Wein!ierK,
II. .\utl., Leii./,., l.Siti), .S. 1,J2. l•■i^^ IIM.) A', mot of N. vatjus ; A7/, root ol" N.
li.vpo^lo.ssiis ; »A', nucleus ahe ciuerea' ; iiXlI, uueleus uervi liypo^jlossi ; J's,
traetus solitarius ; iiinii. nucleus aniliiKUUs ; A7(i, nucleus funiculi lateralis
ventralis; iilji, nucleus I'nui'iili latenilis doi-salis ; /»^(, fiilp. libres from
nuclei funiculi lateralis to the corpus ri'stiforuii' ; I', traetus spinalis nervi
triKeniini ; .s», substantia fjelatinosa ; n\ corpus restiforiue ; iifv, nucleus
funiculi eiiiu'ati ; »/;;, cerel)ral extremity of nucleus fuuieiili Knu'ilis; <ii.
luiclens olivaris inferior; o/.t, nucleus olivaris ai'cesscu'iiis dorsilis; iiiji,
nucleus funiculi ventralis; pi/, pyraniis; ('(((, stratum interolivare lemnisei ;
lull, tihres of the stratum interolivare lemnisei derived from the contra-lateral
micleiis funiculi eiineati and continuous farther cerehralward with the
lateral j)ortiou of the lemniscus medialis; liiht, tihre hands of the stratum
interolivare lemnisei which liav<' come from the contra-lateral nucleus
funiculi Kraeilisand which farther cerehralward form the medial pcutiou of
the lenniiscus medialis: ikuc, nuclei areuati ; far. liluie arcuata' externii'
ventrales which have come fr.un the nucleus funiculi ^iracilis of the ojiposite
side by way of the deeiissatio lenniiscoruni ; rt, libra' arcuata' interna' ; /«,
liosition of the so-called "aberrant bundle " of the medulla cominji from the
dorsjil part of the fasciculus lateralis proprius; fiii. libra' olivocerebellares.
* We know now. from the studies nieiitioned in the precedinj^ chapter,
that tliis voiitro-latcral bundle {aberrierendfn Scifeitstraitgliiindel of von
Beeliterew) is by no means so .simple as von Heeliterew tliouf^ht it to be. It
inchides a whole series of ascending and descending fibre systems — ventro-
lateral spino-cerebellar conjinictival system, spino-ijuadrigeminal system,
*pino-thalamie .system, tegmenlo-spinal system, etc.. etc.
OHOUIMNO AND CIlAIMNCi TtHiKTlIKIJ OF N'KriJOXFX CAl]
with a piirt of those from tlic fiuscicnlus hitcrulis propriiis, an-
sot'ii in the form of u coiiipiict rectaiifiuhir hiiiidU', one on ciu'ii
siih' of the niphf. These huiidU's are directly eoiitiimoiis aliove
witli tlie fa-iciculus h)ii;,ntii(liiialis medialis (posterior loiit,Mtu-
dinal hiindie of many iiuthors) on each siih'. Between the
compact Itundh' in the (U)r.sal re<;ion and the stratum inter-
olivare iemnisci are situated more h)osely arran<,'e(l strands of
lil)res, which, von Mechterew thinl<s, represent in tlie nuiin the
upward continuation of the more ventral til»res of the fascicu-
lus hiteralis proprius of the cord. Anotiier portion of tiu' fas-
ciculus lateralis proprius is continued upward in the form of
isolated hundles in a region lateral to that just described dor-
St?ici
Fid. 103. — ."^clK'niatic srctioii llinm^'li the iii)im'I' |);irt nf tlu' iiicilullii (ililinifiatii at
till' level nt'tlie niot of tlie N. tilnssKidiaryiiKeiis. (.Mler \V. vmi Ueeliterew,
I)i<' I.eituiifi.sUaliiieii iiii ( ieliirii mid Kiifkemiiaik. Deiitseli vun H. WeiiilierK.
II. .Villi., Lei|)/... lS!l!l, S. l,-.(i, Ki-j. l:W. I ir. ec>i|Uis icslifdiiiie ; 17//, radix
(le.sceudeiis N. vcslilmli ; iij'l. imeleiis fiiiiiciili teretis ; /.V. rixils of N. ^.'Idssii-
pliaryiiKeiis; I', tiaetiis spinalis iiervi tri^eiiiiiii : .<», siilislaiitia ;;elaliiii>sa ;
fs, ti-.ictiis solitariiis: fn. e(Miliiuialioii of lasciciiliis lateralis nf the spinal
cord (von Hei literew's '"aherraiit luiiidle") ; Ini,. tilives of interolivary layer
from eontra-lateral iiiieleiis fiiiiiiaili eiiiieati ; hiiu. tilires of interolivary layer
from con tni-lateral luieleiis funiculi uraeilis: iiri. niieleiis eeiilialis infeiior;
iiiiiii. niieleiis amliimiiis ; i>i. ntieleiis olivaris inferior: ois. nucleus olivaris
accessoriiis ; /)//, pyramis: stiiu, stria- meilnllares ; fc. fasciculus centralis
tejfinenti ici'iitnilc llniiht'iihitlui '.
i
sal to the olive. These last fibres, together witli the more ven-
tral of the fibres of the fasciculus longitudinalis medialis, appear
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014
THE NERVOUS SYSTEM.
to bo f'onncctod ijitiniatoly with the nucleus funiculi ventralis *
iind the nucleus centralis inferior,! iuasinucli as, when serial
sections are studied, the fibres followed up from below sud-
denly vanish, at least in large part, at the level of these
nuclei.
The fibres of the main compact bundle (continuous cerebral-
ward with the fasciculus longitudinalis niedialis) representing
most of the fibres from the fasciculus ventralis proprius, and
})r(»bably a few of the fibres of the fasciculus laterali.; pro])riu'-',
can be follov.ed above the nucleus centralis inferior as far as
tlie nucleus reticularis tegnu'nti J (Fig. 401, n't/c sn/ira). Here
a number of the fibres appear to undergo interruption, liutmany
go farther. Of the latter, a few cross in the raphe to pass to the
nucleus centralis sujierior ^ and possibly to the ganglion inter-
j)edunculare (iuddeni. Those most dorsally situated, howevei',
are continuous with the cerebral extension of the fasciculus
longitudinalis medialis (Fig. 40()), which extends at any rate as
far cerebralward as the nucleus fasciculi longitudiiudis medialis
sen nucleus cominissur;\3 posterioris [ohcn'r OcithiiiiDtoriiiski'ni
of Darkschewitsch).
* Misslawsky's " rcspirfittn'y nucleus," Oberstpiucr's Kern tics Vordcr-
Ktr(i>it/(/nnitl/jii/itlels or, us I full it, the nucleus funiculi vcntnilis (l''ij;. 402).
•f Nucleus centralis of Holler, the mass of formiitio reticularis griseu seen
in sections taken tliroufrli the middle of the olive, situated midway iietween
the iiyranuds and the lloor uf the fourth venti'icle and separatiuj^ the fascic-
ulus loiif^itudiiuilis medialis from tlie stratum inti'rolivare lemiusci (Fif^. 401^).
J A mass of formatio reticularis grisea near the rajihe in the pars dor-
salis pontis. It corresponils in part at least to Klechsig's nucleus centralis^
et lateralis incdius.
* i{y the nuileus centralis superior is meant the mass of gray matter seen
on both sides of tlie raphe, ventral to the fascicidus longitudinalis medialis
in sections taken at a level just below the colliculus inferior of the corjiora
(luadriiremina. The nucleus ceTitralis superior extends from the decussation
of the brachium conjnnctivuni above through the region of the central teg-
mental nueleus. being situated nuiinly dui-sal to the latter. The fibres of
the foriiuitio reticularis I'urvc outward to give place to this nueleus. Von
Hechlerew calls it the inncrer t/ltcrcr rrntrd/cr Kern (nucleus centralis
superior medialis). to distinguish it from a small mass of largo cells (nucleus
ei lUralis superior lat(>ralis) at about the level of the nucleus lemnisci lateralis,
situated in among the white filires of the miildle of the fornuitio reticularis
on each side (Fig. 404). This latter nucleus lies in the angle nuide by the
main decussatio brachii conjunctivi witii the decussating fibres of the com-
missure between the mu'leii Xii. vestibuioruin superiores of the two sides
(Fig. 405).
G1U)UPIN(} AXI) ('IIAIXI\(} T()(iETlIKR OF XEUUONK8. 015
Of the recent studies dealing with the ascending fibres of
spinal origin in the fasciculus longitudiiialis niedialis, those of
lleld,* lloche,J and Tscherniak J may be mentioned.
Fig. 404. — .'Iclu'iiiiilic crnss scctiim tliriiiij;li tlic pars dursiilis ]iiiiitis at its.jniK'tiiiii
witli the islliiiius rlHiiMhciK'cpliali. i .M"lcr \V. vmi iScclilcrtw. Die l.fitiiiiKs-
lialiiicii iiii (it'liirn uud IiiickciiiiiaiU. Dcuiscli von II. WCinlMi^. II. .\iili.,
Lcipz. ' isititi, S. :>;{(), Fijr. liis. ) mj, a(|ii(ilii(tiis cc rdni : il/i. fasciruliis IoiikI-
tiidinalis niedialis; /c, fasciculus centralis tefrnieiili • niilidlc Uniiliiiiliiiliii) \
filii, tilircs I'mni the refjion of the ciilliculus inferior In llie nucleus reticularis
tejinienli ; /!', N. troclilearis ; Iniu lilnes of the lemniscus niedialis fmin the
rniitra-lateral nucleus funiculi cuneali ; /i/in. lilires nf the leiiinisciis niedialis
rriiin the <'(intra-lateral nucleus funiculi gracilis: liii/), von Hechlcrcw's
medial accessory lemniscus ; Imsn. von licchterew's scattered hundles of the
lemniscus; lull, lemniscus lateralis; hcs, nucleus centralis superior, pars
medialis; iirsi, nucleus centralis superior, pars lateralis ; iil, nnclens lemnisci
Ial<'ralis ; iirt. nucleus reticularis tej;menli poiitis; /»■,, dorsal, jii-n. middle,
;>Ciii, medial, /(Civ ventral hundle of the liiachiiim conjunclivum ; y;cn repre-
sents the commissure helweeii the nuih i supeiiores nervorum vestilmloriim ;
xfr. siihstantia ferrufjinea. I', radix disi'i'iidens (mesencephalica ) nervi
triKi'mini.
Held, witli the myclinization method, was able to show the
rehition of the ti})res, and esi)eciiilly of tiieir collaterals, to the
nuclei of the formatio reticidaris grisea and to the nuclei of
origin of the nerves governing the eye muscles. Ilis researches
* Op. cU.
t Ilochc, A. Ziir I'dtliolojjio dcr hulhiirsiiiiialen spastiscii-iitruiihisclien
Liihminifjcn. N'eurol. Ceiitrullil.. L(>ipz.. I?il. .\vi (1S!)7), .S. 24','-'jr)2.
\ 'I'scliermnk, A. Uohcr den eeiitraleii Vcrlaiif dcr uiifstei^^otnU'ii Hinter-
straiigliahiipii imd dcron neziehimgoii zii dcji Haluicii ini Vurderseiteiistrung.
Areli. f. Anat. u. Physiol.. Anal. Alith., beipz. (1898), S. 2!>l-4()0.
m
f I
616
THE NERVOUS SYSTEM.
St.gr.c.
Muni
■Hani
Dec Bectil
■ i-Vf •■ ■■■> ;- >■■ w ■
■Ts-nY
IctaKr.
Flo. 4(15. -Horizdiitiil section tlir(Hi>;li tlie iiKMhilla. ixms. uiid niidlirain of a new-
born l)alie. Weifiert-I'al staining. Level of deenssatio l)racliii eon.junetivi
and of nnrleiis retienlaris tefinienti. (Series iii. section No. lOS. ) f './).,
conunissura iiosterior cereliri ; Ihr.ll.c., deenssatio liraeliii eonjnnctivi:
Dff.llidil.. coniniissnre lietween Hecliterew's nuclei ; !).t.. (ilires to decnssitio
tefjinenti ; F.ii.i,' Ciiii.'.. liline arcnatje interntv from the iniclens funiculi
cniieati; F.c, fasciculus cuiK'atns; F.c. to F.r., bundle from fascicidus
cuneatns to formatio reticularis: /•'.(;.. fasciculus f;nicilis: F.l.m., fascicidus
lonfiitudinalis medialis : I..m.. leinnisciis niedialis : [..I., lemniscus lateralis;
Mot. r., radix motorius N. triKennni : .V. 17/.. radix N. facialis, jiai-s secunda;
X.irst.. radix N. vestibnli : .V. IV.. nidix N. aliducentis: .V..\7/., radix N.
iiypotjlossi ; .V. AV,. radix N'. aecessorii ; Sii.ii.I[lA<i). nucleus X. o<'uloniotorii,
pars lateralis; Xk.ii.IU.' h). nucleus X. ociiloinotorii. ])arsinipar; yii.r.s.il >,
nucleus centnilis superior, pars lateralis; .\ii.c.x.i in), nucleus centralis
superior, jiars niedialis ; Sii.l.l.. nucleus lemnisci lateralis; Xii.iiA'll., nucleus
N. facialis; Sii.S.r.r., niU'leiis N. coclileu' ventralis' .Vk.c./., nucleus cen-
tnilis inferior ; .Xii.r.t.. niicleiis reticularis tcKinenti ; ,Vi/,/.. v.. nucleus latenilis
superior; St.iir.c, stratum Ki'iseiini cintrale; .S'/i.l'.. sensor.v root of N.
trigeminus; S.ij., substantia fjelatinosji Kolandi ; Tr.fr. tin. I)., tiiict from
Deiters" nucleus lo tlie spinal cord; T.x.h.V., traetiis sjtiiuilis N, trigeniini,
i Preparation by Dr. John Hewetson. )
GROUPIN(J AND C'lIAININC. TOGETHER OP NEURONES.
♦517
deal more })arti('ulurly, liowevor, with the (lesccmling fibres in
this region, and will be referred to more at length in Chapter
LVIII.
Iloche studied the degenerations in a case of progressive
bulbar ])aralysis witii Weigert's method and with the method
of Marchi.
!i!
Cnniniissura
/xinteriiir
Collins
liineale
Mnilcrin
y. iichUi-
motorii.
IkCUSSIltil)
in'iriintiii
\iiclciix nirvi trochUinium
Inirli-
Ivuris.
Fiisiirithis
loiii/iludiiiiilis
niediiilis.
h'udi.r .V. /(iriiilis Surli}is tiervi
{(jfiiH iiiteniuiiii. hiiiiiiylihixi.
A'i((7(i/» tirrvi
y U/iiHsiijihiiryitgei.
yiirlfiisfiiiiinili
{IlllCillS.
Kdsrii-uhts
gracilis.
Ciirpus
iiiaiiiiiiilldi'e
Dt'riissdtio
liriicliii
ciiiijiincfivi
Fihrir
trans-
IK'C.SVI'
ipriijiiii-
dcB)puiitis.
Fibr(E \j/
trans-
fersa' f.rnniisrns
tsuiiir/iciiilis) iiuiliiilis.
pant is.
Fasriruli
liiii;iilii(li-
niiirs I pyra-
iiiiiliiles).
^
FUi. 40(i. — A siiftittal scctinn nf the iiicdiilla (iblimnata, pons, and nicscnccijlialon
parallfl and cldsc to tlic middle line; child a^cd (lircc niontlis; nictliod of
Wcificrt. I Al'tor A. Hrucc. Illustnitions ol' the Nerve Tracts in the Mid- an(l
Hin(l Hrain and the Cnniial Nerves arising therel'roni. Kdinh. and
Lonil.. IMil'^. pi. xxvii. Kifj. 1.) The fascieuhis lonKitiidinalis inedialis and
its relation to the fasciculus vcntralis proprius of the spinal conl are particu-
larlj ix'll shown.
Tsehermak, after experiments upon cats and studies with
Marohi's method, has given the latest description. According
to him, the long neurone system from the spinal cord to the
cerebrum by way of the fasciculus longitudinalis medialis * has
its origin in the ventral horn of the spinal cord. The peri-
karyons and dendrites are situated in the group of commissural
* Dds avfuteiyetiile {cmtralaxone) Hpinocerebralsystem im dorsalen
Ldngshundel of Tsehermak.
t
i -'•
(US
THE NEUVUUS SYSTEM.
cells in the vontnil liorn, the axoiics ascending in the ventral
funiciihis. In tlie nuMluUa ol)1()iiirata, at the U'vel where the
central canal of the spinal (-(jnl witleiis out to form the fourth
ventricle, the vent.'al and lateral funiculi become separated
into two groups of fibres, one medio-dorsally placed (con-
tinuous farther up wUh tiu' fatciculus longit'idinali.s medialis),
the other veiitro-lHterally placed. The ascending spiiu>('e''el)ral
system under consideration enters the first-named fibre complex.*
The ascending fibres give olf many collaterals to the same side
and to the opposite side. The collaterals to the same side pass
lateralward to the nucleus lu-rvi hypoglossi, the nuclcMis nervi
abducentis, the nucleus nervi trochlearis, the nucleus nervi
oculomotorii, the nucleus centralis et lateralis inferior, the
nucleus centralis et lateralis medius, and the nucleus centralis
et lateralis superior. The collaterals to the opposite side pass
mediahvard across the raphe and end in the various nuclei of
the format io reticularis grisea.
The longest fibres of the ascending system of the fasciculus
longitudinalis medialis, having reached the level of the collicu-
lus superior of the corpora fjuadrigemina, swing around latero-
dorsalward, to pass between Darkschewitsch's nucleus and the
nucleus lateralis superior, the axones terminating in the cells
of both nuclei. A part of the fibres go through the pars ven-
tralis of the commissura posterior cerebri to terminate in the
corresponding nuclei of the o])posite side.f
According to Held ami Tschermak, the neurone system
under discussion represents a deep crossed connection (the
crossing taking place low down) between the spinal cord and
the nuclei of origin of the motor cerebral nerves as well as the
nuclei of the formatio reticularis grisea of both sides as far u])
as the commissura posterior cerebri.
There has been a great deal of controversy between von
Bechterew, von Kolliker, Held, Ramon y Cajal, van (iei\uchten,
* Vorilcrxi'iteuatntnf/reKt ilcr MifteUiiiie (Held).
f Tlu' sujicrior liilcrul nucli'iis is ("ontinuoiis lioadward with the o'litrn
miilian of the nucleus medialis thalanii. It will bo noted that the pars voii-
tnilis of tiio pointnissura posterior cerebri contains crossiM' fit)res of llie
aseeniiing spino-cerebral system which run in ttu' faseicuhis longitudinalis
medialis, while the pars lorsalis of theconunissura posterior cerebri contains
axones from tiie nuclei (if the dorsal funiculi which arrive in this region by
way of the lemniscus medialis.
(iUOUl'lNO AND (;ilAININ(i TOCiKTlIKR OF XEUllOXKS. (;i<»
II-
lu>
lis
[IS
Miiliiiini, and others conecirniiig the rolutivc juiiiibcr of iiscend-
in;,' iind dcsct'iidiiiff lihri-s in tlic fiisciculus lonfjitudinalis nic-
diiilis iind in the other l)iin(lles of tiie fornuitio reticuhiris ulha
Some authors hohl that the majority of the fibres are for centrip-
etal conduction ; others maintain that certainly the majority
of the fibres conduct in a centrifupil direction, ami that the
paths are motor, not scTisory. 'I'lie truth seems to lie in a nu'an
between these two extreme views. In all probaltiiity we have
here to deal (1) with ascending or centripetal paths consisting
of some long inaxones and also of a number of shorter super-
imposed inaxoncs (sensory JUMirones of the second and of higher
orders) by means of which motor nuclei may be all'ccted by im-
pulses arriving along sensory nerves an<l possibly l)y nu'ans of
which impulses concerned in sensation can be carried toward
the cortex ; and (•■i) with descending or centrifugal paths by
means of which the motor nuclei of the rhombencephalon and
sjjinal cord are brought under ttu" iutluenee of the centres of
the midbrain and perhaps of higher regions.
Some of the ascending fibres may pass directly into the me-
dial lemniscus, or independently into the hypothalamic region,
or from some of the gray masses in which many of these fibres
end axones nuiy be given otf which run by way of the medial
lemniscus or through the formatio reticularis to join the other
sensory paths in the hypothalamic region.
Just here it may be mentioned that Ciaglinski * has described
a long centripetal path situated in the substantia grisea of the
spinal coi'd. He is of the opinion that the buiulle he describes
may have to do with the conduction of impulses concerned in
pain ami temperature sensation. I have no personal knowledge
of this bundle, and thus far 1 know of no research conflrmijig
the results obtained by Ciaglinski. The subject of centripetal
paths in the substantia grisea is of course of deep interest in
connection with the elective sensory disturbances met with in
syringomyelia and in central hajmatomyelia.
The paths dealt with in this chapter will be further con-
sidered in Chapters XLVIII and XLIX. f
* (Miifilii'i^ki, A, Tiangc soiisiblo Riihtion in dcr <;rauoii Siibstan/ dcs
Rufkciiiiiarkcs und ilire expcrimcntelle Degetieratioii. Neurol. Centralhl.,
Loil)/.. Ril. XV (18i)()). S. 77;j.
f Cf. also. Camphi-ll. A. W. On the Tracts of tlie Spinal Cord ami their
Degenerations. IJrain, bond., vol. xx (1897). pp. 488-5:{.5.
41
r:;n-
' 1
■
hj.!
2. Central Neurones, the Perikaryons and Dendrites of which are situated in the
Nuclei terminales of the Axones of the Cerebral Peripheral Centripetal
Neurones.
("HAI'TKR XLIII.
CKXTKAL \F:ri{()xr:s pKUTAixiXi; to tiii: n. '-.vfirs, x. (;lo.sso-
piiakvx(;i;ls et n. ixtkkmkdils.
Cerebral pontripctal neurones of tlie seeoiKl onler — Tlie nueleusalie oinerpm
— Studies of Holler and Ilolni — The nucleus tractus soliiarii — The
nucleus coniniissuralis.
We puss next to the consideration of the central neurones
pertaining to tlie cerebral sensory nerves. Their cell bodies
are situated in the various masses of gray matter (nuclei termi-
nales) in the rhombencephalon, in which are found the end
ramifications of the axones of the peripheral sensory neurones
belonging to the N. vagus, X. glossopliaryngeus, N. vestihuli,
X. intermedins, and N. trigeminus. The medullated axones of
these central neurones pass, partly directly, partly after decussa-
ti(tTi, into the medial U'mniscus. into the fasciculus longitudinalis
medialis, iiiul into certain other bundles which run longitu-
dinally in the formatio reticularis. The neurones here con-
cerned connect directly or indirectly by means of superimposed
neurones with the cerebrum through the cerebral peduncle.
A few of the axones doubtless pass into the cerebellum. The
individual groups of central neurones can best be understood if
each be described separately.
It has been stated above (under the description of the pe-
ripheral sensory neurones) that the sensory axones of the X.
VAors, X". (;LOSSoi'iiAKVX(iKUS, ami X. ixtkkmedhs terminate
mainly in (1) the nucleus alas cinerea?, {"-i) the nucleus tractus
solitarii, and (3) the nucleus coniniissuralis at the spinal ex-
tremity of the tractus solitarius.
G3U
OllOUPlNG AND CllAININU TOCtKTIIKIl OP NEL'KONKS. (121
con-
posed
uncle.
Tlie
)od if
le pe-
lie N.
[inate
laotus
111 ox-
The nucleus aht cinereie, that obliquely longitudinal mass of
gray nuitter extending forward from near the spinal extremity
of the nucleus nervi hypoglossi helow to a few iiiillinietres l)c-
yond the anterior (or cerel)ral) extremity of the same nucleus
in front, eorrespoiuls, in the Hoor of the fourth ventricle, to the
fovea inferior and ala cinerea (Fig. 407). It is characterized in
transverse sections stained by Weigert's nu'thod by its poverty
in nu'dullati'd fibres, thus contrasting strikingly in appearance
with the nucleus nervi hypoglossi wiiich lies medial and ventral
to it. Just how much of the nucleus ahe cinerea? receives ter-
miiuils and collaterals from the X. vagus and just how much of
it receives fibres from the N. glossopharyngeus seems to be
doubtful. While sonu' authors, along with von Kolliker,* as-
sert that in microscopic preparations it is impossible to decide
this further than to state that the uppermost parts of the
nucleus belong to the X. glossopharyngeus, and the lowermost
parts of it to the X. vagus, others, with Holler f and Holm, J
are strong su})porters of the view that the nuclei of these two
nerves are entirely independent of, and on close examination
easily distinguishable from, one another. Certain it is that in
the gray mass which we call the nucleus ala' cinerca3 it is possi-
ble to make out more or less distinct groups of nerve cells.
According to Holm (Fig, 40S), in a section through the middle
of the terminal nucleus of the vagus, three groups of cells can
be distinctly made out — (1) a ventro-medial portion of the vagus
nucleus ^consisting mainly )f large cells ; ('->) a dorso-latoral
portion of the vagus niu-leus consisting chiefly of small cells;
and (3) the nucleus of termiiuition of the X. glossopharyngeus.*
The view that the dorsal vagus nucleus is not sensory, but a real
nucleus oriyinis for motor fibres of the nervus vagus, advanced
* Op. cit., s. 240.
t Holler. V. V. \V. Der ccutrale Verlnuf des XtTviis Gldssophnrynfrrns :
(les Nucleus lateralis inetliiis. Arch. f. mikr. Aiiat., Uoiin. Bd. xix (lH8(t-'yi),
S. 347-383.
X Iloliii, II. Die Aiiatoinie uiul Patholofjie des dorsalcn Vapjuskerns ;
eiii Heitray ziir Lelire der Resi>iratiiins- und Iliistenreflex- Centra, ihrer
Kiitwickeluiitf und Degeneration. Arcli. f. path. Anat., etc.. Herl.. I?d. cxxxi
(18!)3). S. 78-1 '20,
* Holm, from his study of patholo.trieal cases, has concluded that the
centre for the tracheo-broneliial (couj^hinj:) rellex is to he sought in the
dorso-lateral part of this dorsal nucleus of the vagus, while the true respira-
tory centre belongs exclusively to the ventro-medial part of the nucleus.
i , it
n
lit
ul
<;22
TIIK NKllVOUS SYSTKM.
Fig. 407.
Fid. 407. — hiiiKnun inTparcd l)y Miss V. Saliiii ('mm a scries of st'ctiinis tlirmiKli
(he liiiiiii of a iicw-lioni lialii'. sliowiiiK llii' niiiici of the ccrrlirai iicivis and
till' ana of exit anil of ciitiaiicr of tile roots of Ilu'Cfrcliral nerves in flat |iro-
jeclion. ((, line of lateral eii^e of fonrtli ventricle; (/, (/. (/, tl, fovea inferior;
('. fovea snperior; ;/. lateral surface of rlionil)enee|ilialon ; ///., area of exit of
N. oeiiloinolorins ; /!'. . area of exit of N. troehlearis ; I',, area of exit and en-
trance of N. tri^etninns; 17., area of exit of N. aliductns; 17/.. area of exit ipf
N. facialis; 17//. 1 (■(»■/!. 1, area of entrance of N. cochlea' ; 17//. rc,s7/7(. , ai<';i
of entrance of N. vestilmli ; /.V. and .V., area of entiance of N. Klosso|diar.vn-
jjeiis et va^ns: XL, area of exit of N. a< cessorius ; A//., area of exit of N.
hypoKlossns; Xit.ii.'Il.. iniclens N'. ocnlo-inotorii ; .%'».». /!'., iiuclens N, troeh-
learis; Xii.ii. I '.I «/./(. i. tnndi'iis niotoriiis princeps N. triuemini ; Xii.ii. 17.. nn-
cleiis N. ahdiiccntis ; Am. 11. 17/., nncleus N. facialis ; Xk.h.. nncleiis ainhi^nus;
Xii.ii.c., nncleiisahecinercii' ; XiDi.r.iii., nindeiis N. vestihnii inedialis ; Xii.ii.r.s.,
nncleus N. veslihnii superior; Xi(.ii.r.l., niicli'iis N. vestihnii lateiiilis ' l»eitersi;
Xk.ii.c.iI.. lindens N. cochlea' doi>;ji I is; Xii.ii.c.r.. inicleiis N. cochlea' ventralis ;
yii.ii.Xll., nncleus N. liyiioKlossi ; l\.(l.ii.t.,r,n\\x desceiidciis , nieseiicephalica|
N. tri^'cniini ; I'.il.ii.r.. i-.idix descendeiis N. vcstilmli; >'.(/., snhstanlia «elati-
nosa ; '/'. .«)/., tnictns solitarius ; Tr.s.ii.l., tractiis spinalis N. triKcinini; IV»^,
ventral horn cells. 'I'he nuniliers to the left of the dniwint; inclicate approxi-
matil.v the levels of tile corr>-spoiidin<; tninsver.se sections represented hy
l''ij;s. :«)H to :{17.
The plane of the sections from which this diaKnim was made is not (piite trans-
verse hut soniew!i;it olili(iiie; the dorsal surface of the medulla has heeii
struck hy the knife more cerehralward than the ventral surface, the aiiKle
formed hy the plane of the section with the longitudinal axis heiiiK ajiproxi-
mately seventy de^'n-es, as measured on the <'eieliral side. This accounts for
the evident islijjhti displacement e<' re lira I ward of the structures in tlie ven-
tral portions of the sections as compared witli those in the dorsiil iiortions.
I
;,■ ' ■ :h,
i
m
J
1
1
,!
1
if- f i : . ■
^^ '*■!.;. .
<(|{(>riMN(i AND CIIAIN'IN*} TOCiKTIIKU ()!<' NKl'ltONHS. r,-2'.i
by DccH* lis ii H'siilt of stmly with the int'lliod of atropliy, iiiid
rccciilly siipportt'd (for Niiiiiotli rriiiscli') by MuriiicKco, f uh a
ri'siilt of iiis stndifs of the midt'iis liy Nissl's method jiflrr sfc-
tioii of the iici'vc, diM's not scclii to he wt-ll foiiiid('<l. We know
now that thu chan^'cH siK-h U8 Murint-aco Uuscribcs can rt-MilL
AkcI'Iih ImiiiiKihs A.
yliiiiiii)i>/iiiriiinjii.
I'l'iitriculuH iiuatlu».
X.
■3\
><
III
V3»(
I.? '
~ ?■'=
i C ;
•■^*'^
7S^- I
ICadix .V. vaiji.
b'ilirii' iirciuiliv iiitfiim from
tnicliia siilitiniiiH.
Fi'i. KW.— Pill iiri'|)!initicpii from tlii' iiit'diilht of a cliild six weeks iil<l ; section
tliroiiKli (lie Miiilille third iif the liurhns .'ihe eiiiereie, 1 Alter II. Ilnliii. Areli.
r. iiiith. Anal., et<., Herl., IJil., e.xx.xi, IHUH. Taf. ii, Fin. 3. 1
not only from lesions of the axoiie of ii j^iven neurone, but
also from injury to other neurones the a.xones of wliich bring
iinpulsos to it. ((.'f. Chiipter X.W.)
Stranj,'e as it may appeiir, the informtition wp pos.sosa onn-
oernin^ the course of the Jixones of the neurones, tht! cell !)odi<\s
of which are situiited in this intportant nucleus ahe cinereai, is
e.xtremely meafi;re. It rciilly amounts to a few vaj^ue state-
* Dros. <). Uebpr die nozinhiinfj ties Xervtis accessorius zu den Nii. vtitriis
und hypoplossii.s. Allg. Ztselif. t. rsychiiit.. etc.. Her!.. Hd. xliv (1HH8). S. «"),").
t Mftrincsc'o, G. Lps iioyiiiix iiiiisculi)-stries et miiscido-lisses du pneuino-
gastriqup. Coinpt. rciid. Snc. t)iol.. Par., 10 s.. t. iv (IHKT). p. 168.
Ii
0l>4
THE NKIiVOUS SYSTEM.
II*).''
jf !.
nu'iits as to tlu' ori^'iii of libra' arcuatu' interna' from the nii-
clens, some of wliicli are supposed to pass to the medial lemnis-
cus, others to the faseieulus longitudinalis nieilialis or to the
formatio retieularis alba.
Fl(i. 109. — Cniss sfctiim tliroimli tlic rlioinlicnccpliiiliHi <if n fiHir-day-uld tiKiiist".
At'lcrS. Iiamoii y Cii.jiil. licilni^' /iiiii St'idimii dtr Mitlullit < )lilcitiKMt!i, t't«'.,
I.cip/.., ISiMi. S. ts, I'"!-;. i;{. I .1, iiiulcus N. liy|Ki},d(issi ; It iiiultiis ckiii-
iiiissiinilis ; (', niKdcus olivaris iiiCcridr ; />, li-ictiis siiiiialis N. triKfiuiiii ; /•',
nidtor mot of N. viiftus and N. nlossopliaryiiKcns ; /■', nucleus aniliinnus ; (I.
jKistcrior cxtrfniity of nucli'iis N. vi'stilinli radicis di'sccndcnti.-; ; //.cross
section of trad ns solitarins; /., lilires K"i'iK to nnel<'us olivaris inferior; n,
pyraniis ; /). collalenils from tlic ii.vniinid anil from the sulist.intia all>a lateral
from it; (/.collalenils from I lie i'asciculiis lati ralis proprins ; c, sensory col-
latenils for the nucleus amliiKUUs ; /. rc'uri.'iit lilu'es in motor roots wliicli
run toward tractus spinalis N. triKcuiini : ,;'. irossed motor root li lues of \.
vatins ami N. },dossoplutrynj;eus ; li. eoll.iterals of the seusiu'y root of the N.
vaKUs and N. Kl<>^'«>pharynKeus rnnniuK in the fasciculus solltarius ; i, proto-
plasmic coniniissurc lietween the nuci"! \. hypuKlossi of the two sides.
Tlie views held coneerninfj the nucleus traetus solitarii are
also very divergent. A study of horizontal sections through
i"im^-taiM»— ■-
CiKOUlMNO AND ('Il.MNIN<i TiMiKTIIKU (>F NKl'UoNKS. (;i>:
tlu' hahy's rliotnlji'iiccplialoii has, liowcvcr, coiivincod inc tliat
wliili' tlic majority ol' fibres I'litcriiii^ tlic tractus solitariiis and
tcrniiiiatiii^ in its iiuciciis arc (i('riv<'(l from tiu' N. jfjosso-
pliaryii^'t'iis, ncvertliclcss a j^oodly iuiml)fr of tiltrcs from the
N. vagus also follow tlic same coiirsi". It seems |)roi)al)le that
the mieleus truotus solitarius also receives terminals and collat-
erals o
f fihr
es entcriiiir as the
intcrmediu
lie nucleus
tractus solitarii, aside from the nucleus commissuralis at its
ill
t-S^
'.J .
■ve.-
111-
/■:.
'nss
".
JTill
.1-
■h
N.
N.
pt.i-
re
I'm. JKt. Tiiiiisvi Tsc scclidii tlir(Mi;.'li tlir iikiIiiIIm iililniifiiilii iit' a iiumsc at
the IfVt'l cif the iniclciis ((iiiiiuissiinilis. lAI'trr S. Uaiiioii y Cajal, ItcitraK
/.iiin Sliitliiirii iliT Mfcliilla OMiiiitiala, ttc. liri^li r, Leipz.. IsiMl, S. 17, Vin-
1^.1 .1, miclciis CDiimiissiiralis : /(, imclciis N. liyimKliissi ; ('. diciissalio
Iciiniisciiruiii : I), traiisvci-sc scclion of tractus scilitarius ; /•,'. cciiti-iil path I'lir
N. r. IX; II. cell 1)1' nucleus ('(iiiiiiiissmalis ; h, c, tcnninal tilircs ol' N. va^us
ct N. Kl"^^"l''''0',vnKcus ; il, ciininiissurc Ininicil liy <i>llatcnils of liypuKli'ssal
nuclei ; ij. /. collaterals ofseusory axoucs of the secouil oriler for the nucleus
N. Iiypofjiossi.
spinal extremity, consists of a mtiss of j^ray matter which sur-
rounds till' tractus solitarius alonji its whole lonjjitudinal ex-
tent almost like a cylintler. In this mass end certain colhit-
erals and a few terminals from the tractus solitarius, aud
in it are situated the perikaryons and dendrites of sensory neu-
i i
6^26
THE XEIIVOUS SYSTP]M.
ronos of tlio second order. Whitlier their axones go has not yet
been satisfaetorily deternuned.
If Ramon y C'ajal's studies be confirmed, then the nucleus
commissuralis (iiis Comiinssurenkern or fjaiKjUon rotnmi,s,surah')
must be reganU'd as one of the main depots of the cell bodies
of the central neuroiies now being described. According to
him,* three fourths of the fibres of the tractus solitarius de-
cussate at its spinal extremity and terminate iu the form of
a most complicated plexus of fibrils in this nucleus (Fig.
409). He describes the cell bodies of this nucleus as being
small, spindle-sliai)ed, ovoid, or triangular; their dendrites are
delicate and almost smooth. The axis cylinders are extremely
delicate and form small bundles, which, passing laterally and
forward, reach the 1 :nniscus, some of tiieni crossing in the
raphe. Isolated fibres can be followed through the formatio
reticularis grisea to a region (Fig. 410) which corresponds to
the path of the axones of the central neurones of the trigeminus.
* Op. fit., S. 46.
gl';
fMh.
lU i.
M
CHAPTER XLIV.
m
CENTRAL VKSTIBULAR NEURONE SYSTEMS.
The nuclei teriiiiiiales X. vcstibuli — Axones from these nuch>i — Medial and
lateral central vestil)ular paths of Uamun y Cajal — The ventral part of
the decussatio brachii conjunctivi a vestibular coniniissure — The central
vestibulo-spinal bundle — 'i'he fibres cxtendin;^ between the nucleus
fastigii aj )eiters' nucleus — Inlluenee of vestibular impulses upon the
eye-muscle nuclei.
The cell bodies of the sensory neurones of the second order
pertaining to the N. vestibuli are situated mainly in (1) the
nucleus nervi vestibuli mediali>^, (2) the nucleus nervi vestibuli
spinalis (radicis descendentis), (:}) the nucleus nervi vestibuli
superior, and (4) the nucleus nervi vestibuli lateralis (Fig.
411). Finally, (o) a few of them, as we have seen, must be
situated in the cerebellum (Ramon y Cajal 's nucleus eerebello-
acusticus, the nucleus fastigii, and perhaps in the nucleus den-
tatus and the substantia grisea of the cerebellar cortex). The
exact location and reciprocal relations of these nuclei have been
described above in connection with the peripheral centripetal
neurones. The course followed by the axones which go out from
the cells of these nuclei is what interests us here. In the brain
of the new-born child, stained by the method of Weigert-1'al,
there can be made out going from the nucleus nervi vestib-
uli medialis and from the nucleus nervi vestibuli spinalis
radicis descendentis numerous medullated internal arcuate
fibres. Tnese fibres differ from the majority of internal arcuate
fibres of the rhombencephalon in that they pass close to the
dorsal surface instead of making a deep curve ventral ward.
The most dorsal of these run toward the raphe and pass in among
the fibres of the fasciculus longitudinalis medialis. Some of
them turn to run forward in the fasciculus of the same side ;
others of them, after decussation, turn forward in the fasciculus
637
t
tiL'S
TIIK NKUAOl'S SVSTKM.
Fi(i. 411. — niiiKnim rciin'sciiliii}; fljit rcciinstniclion of tin' nuclei nf (cniiiiiiitidii
i)l'tlicciiclilc!ii'Mli(l vestibular nerves, i .M'ler Kliireliee U. Saliin,,l(ilins lliipkjns
Ilosp. Mull., Halt., vol. viii, 1SH7, \'\ii. l.i The line n, <( reiireseiils the lat-
eral wall ol'the ventricle; the line h I'drrespeiKls to the lateral outline of the
cor]ius restiforuu' : the line ili to ('4. ('1 to (/;,. and the line c. c, c correspond to
the sulci in the lloor of the fourth ventricle; i'.d.. nucli'Us nervi coclilea'
ilorsiilis; (\v., nucleus nervi cochleie vcntralis; liie urailuated line cor-
r<'spouds to the middle line of the lloor of the ventricle; /•Vf/c, (loc<ulus;
K. I'll, knee of nervus facialis; /... tnedial ptu'lion of nucleus nervi vestihuli
latentlis >I)eiters); /,]. lateral portion of niu-leus nervi vestihuli lateralis
(I)eiters'; .V. tottel her with )', i\ucleus nervi vestihuli niedialis iSchwalhei;
\'iii\ X'll, mndeus nervi hyjioKlossi ; .\iir. 17. nucleus niTvi aliilucentis ; /*./..
pedunculus llocculi ; .V. w. /(. I'., nucleus niotorius iirinceps lu'rvi trigeiuiiii ;
\.<>.s., niu'leus olivaris suix'ricu' ; .V. .v. I'., nucleus nervi trijicuiini (sensory);
.V. ('.. root hunille of nervus cochleie ; .V. ri'st., root liundle of nervus vestihuli ;
/'. (/. II. re. radix descendeiis lu'rvi vestihidi ; N., nucleus nervi vestihuli
superior 1 Hechterew ' larea inclosed in the tiroad hlack line); Tr. x. 11. f..
tnictus spinalis nervi tritieniini ; )'. nucleus //. —anterolateral p<u'tion of
inicleiis nervi vestihuli niedialis; i. decussiitio nervi tri^einini.
<;i{(>riMN'(i AN1» ('ll.\ININ(i TOdKTIIKK OK NKl'UoNKS. «',.j<)
(if I lit' opposite side* 'I'lic mujoriivol' tlic iixoiics, Troiii tli(!
medial luiclciis iiiid froiii tlic miclt'iis of \\n' dcsccMdiii^ or
spitiiil root, however, appeiir to run to a region iti tlic foniiatio
reticularis sitiij'tcd lateral and veiitrul from the iineleiis nervi
altdneciitiH (I'Mj^. W'i), where tliey assume a loiiffitudiiial dir(((v
tioii,t Homctimes hifurcal intr into im ascendin^^ and a dcHceiid-
inj,' limi». A '^ood manv of lli
axoiies cross tlie midult
Ih
<ll(
line
FlU. W'i. — Scctiipii tln'oiljili (lie ilioiiili(lW(|iliiili>ii lirjciw tin- ticim iiiliriiiiiii
mdicis N. riiciiilis. lAflrr S. Uiiiim'iii y ('ii.iiil, ItiiliMK /.mn Sliidiiiiii dcr
Mcdiillii Ohlonijalii. Ill-,, I'.iislir. I-iipz.. I.siiti, S. 71. KIk. :i(l. i .(. roiiniui,,
riliriiliiris urisi'ii in wliirli llir lalcnil iiiilnil piilli 'iixoiiis id' rciil lipitiil
lirllliilirs id' till' srciilid iHiIrr rulilli rlid willi I 111' N. vrstilillli ' lii'> ; /i. llili-l'iil
piiitioii id' 111!' iiiirli'iis N. vi'^liliiiii >>piii;ilis; T, nirdiul piiilimi of tlii'sinn';
7'. Inirliis spiiiiilis N. I i'i«riiiiiii ; /'. rmpMs ii'stiriiniii' ; n, h, nils llir iixoiirs
id' wliirli nm 111 till' luti'nil irnli-iil vrslilmlar path; </, rrlls llii' iixiiiii;^ of
wiiirli Kii latcnilwaid ; c, /. axniics wliicli run ti> thr laplii'. Tliir letter c
indieateH tlie iixoiics.
it I
,1
and reach a similar '• Ititend vestihular hundle " (»n tiie opimsite
sidi-. A iiumher of the cells in the nucleus of the descendinjf
root send their axones lateralward and dorsahvurd to niin<^le
with the fllires of the descending root. As yet the exact termi-
nation of these axones has not been satisfactorily made out.
* The ccntriil vestil)ii]iir path lumiiiij; in tlie faseieulus ioiigitiRlinaUs
nit'diiilis is tlio one referred tn ijy i{ami')ii y Cajtii as tlie '• iiiiiere Vestitiu-
lai'isliahn," or nu'dial vestitiiilar |uilh.
f 'I'tiis JdnKilii'liiial l)iiii(lle is culled by Uuinuii y Ciijiil "die laterule
Vostilnilarisbiihii."
^^i^lTnr
i
IIJ
630
THE NERVOUS SYSTEM.
The nucleus norvi vestibuli superior (von Bechterew) con-
tains large numbers of multipolar cells of smaller size than
those of Deiters' nucleus. The axones follow at least two
directions. A part of them pass through the nucleus and
m;
lit
i^M
Fia. 413.— Frontal section tlininKli tlic imns. includinf; tlic covpns rcstifornio,
Deiters" and Hcclitcrcw's nuclcns iind tlic vermis of tlic ccrcliclliini of a
iicwlMirn mouse, i AftcrS. liainoii y ('ii.)al. i'.citra},' /.iini Stiidiiini der Medulla
()l)lon>;ata, etc.. P.n'sler, IS'Di, ,S. (i,"). Fif;. 1«. ' -I, corpus restiforine cut
leufltliwisc : 11 '-..dix X. vestibuli: (\ tractus spinalis N. tri«einini ; ]>.
luu'leus fastifiii . A.', nucleus N. vestibuli sujierior i von Iie( literew i ; /•'.
superior extremity of nucleus X. vestibuli lateralis iDeitersi; (.', nucleus
dentatus ; n. asceiidinfr limbs of bil'urcated axones of X. vestibuli: /(.col-
laterals from tliese to Deiters' nucleus; c. collaterals from axoiu's of corpus
restiforine; c. descendin).' limbs of bifurcated axones of X. vestibuli; </.
axone from cidl in Hecliterew's nucleus: /. collaterals from the axones of
the corpus restiforme to fiie cerebellar licniisidiere : f). fibres fnmi corpus
restifornu' wliidi appear to brauidi in the cerebellar cortex ; h. collaterals
from the coriuis restiforme to the vermis: ('. free bi-inichint; of an axone in
the nucleus fasti^ii; j. ti'il>< of the nucleus fastigii, the axones of which enter
the vermis.
(iHOUPING AND (MIAININO TOGKTHER OF NKURONKS. (i31
throuj^'h the bruchiun. conjunctivum into the ferehollum, upiuir-
I'litly foHowiiif; the same course us the fibres connecting Dei-
ters' nucleus with the cerebellum {rldv infra). The majority
pass ventralwanl and mediahvard (Fig. 41:5) to tlie region of
ll'ill'IUC,
\\ of il
(.•(\ulUi
lie flit
li; IK
liifU'\is
]/(. ct.l-
loorpiis
TiU; <'..
lines 111"
Icdi'Iiiis
Vtfi'sils
liiif ill
St.g
R.d
Fici. 414. — Triiiisvcrse sci lion tiiroiifjli bruin of iicwiiorn liatic. Level of collicnli
inferiores of i'or|(oi'a iiniKlrijieniinu. i Weijiert-l'al. series ii. section No. 2il0. >
.(i/. (•('(■., iKiuednctus cereliri ; a. til res rnnniiif; from hiteral lemniscus toward
dorsal l)order of l>raeliium coii.jiincliviini : />r. Ctni}.. bracliium conjunct iviini ;
r.c.(. . comiiiissure lietween tile collicnli inferiores; /^cc./icc/i.. ventral [lortiou
of lu'acliiiini eonjiinctiviiin, wliicli in reality forms a commissure lietween the
superior nuclei of the vestilmlar iiervesof tlie twosides ; F.l.)ii.. fasciculus lon-
gitudinal is media lis : I'. I'll., fasciculi lon;;itudiiiales iiontis i |)yraiiiidalesi ; /,./.,
lemniscus lateralis in larne part teniiinalintr in the nucleus of the colliciilus
inferior : /,.;/!., lemniscus medialis ; A./I'.. N. trochlea ris ; Xii. Cull. inf.. nucleus
collieiili inferioris ; Sn.c.i.i I <. nucleus centralis suiierior, pars lateralis;
.Vh.c.sm mi ). nucleus centralis superior, iiarsmedialis ; U.d.ii. I'., radix descendeiis
[meseiieeidialica] N. trifieniini ; .'•7. (/r.c, stratum Kriseiini cciitnile. il'reiiara-
tiou by Dr. .Iidin Hewetson. i
Deiters' nucleus, where some of them probably end, though
mt>st appear to pass through the nucleus (perhaps giving oif
collaterals to it) in order to follow the same course is that pur-
sued by the axones arising in it. The axones horn Riimun y
...I .
I ,1
\\
( ' r
m:W.
<i32
THE NKllVOUS SYSTKM.
C'ujiil's mu'k'us corobello-iicusticus appiirently follow the same
course as those from von Hochterevv's nucleus.
V^on Bechterow * describes a bundle of fibres runnin<j from
the nucleus nervi vestibuli superior of one side to tliat of
the other by way of the l)rachia conjunctiva. Tiie libres which
make up tliis l>un(lle are the first of all the librcs of the brachium
conjunetivuni to become meduUated, and occupy in the middle of
the pons its most ventral part. Von He(;hterew asserts that the
fd)res have nothing to do with the cerebellum, that they run
forward as far as tiie upper part of the pons, l)ut before reach-
ing the general decussation they leave the brachium eonjuneti-
vum and pass over to the other side in the form of a commis-
sure. Portions of this vestibular commissure, winch is relative-
ly iiKh'pendent of tlie main decussatio brachii conjunctivi, are
shown in Fig. 414 and Fig. 415. Tiie connection of the axones
of these fibres with the cells which give them origin by (Jolgi's
method has thus far not been established. In Miss Florence
Sabin's wax model of the medulla oblongata, however, the re-
construction shows the intimate relation of von Hechtcrew's nu-
cleus to the ventral part of the brachium conjunetivuni.
The course of the axones of the neurones, the cell bodies
and dendrites of which constitute the nucleus nervi vestibuli
lateralis (Deiters), has been studied by nearly all investigators
who have been active recently in this field, and he who will
know this region in its details should study the articles of
Obersteiner, von Kolliker,f Sala, J Held, * llamon y Cajal, || and
Risien Russell.'^ The cell bodies in Deiters' nucleus are large
and multipolar, resembling closely, by all methods of examina-
tion (including that of Xissl), the motor cells of the ventral
horns of the spinal cord. The axones of the cells are of larger
* von Bficlitcrew. W. Op. cit., S. 117 u. 185.
t Op. cit., S. 260 /.
^ Sala, L. UL4)er den Ursprunp dos Ncrvus aousticus. Arch. f. niikr.
Anat., Bonn. lid. xlii (180i5), S. IS-W.
* Held, H. Bcitriiffc zur feiiicrcn Anatoniie dcs KltMnliirns nnd dps
Ilirnstaniiiies. Arch. f. Anat. u. Physiol., Anat. Ablli., Ijeijiz. (1893), 8.485-
446.
I Ramon y Cajal, S. Bcitraj; ziini Stiidiiiin der Medulla Oblongata,
etc. Deutsch von Rresler, Leipzig (1896), S. 67 tY.
^ Russell, .T. S. \l. The Origin and liestination of Certain AfTerent and
EITerent Tracts in the Medullji Oblongata. [Abstr.J Hril. M..J.. Lon.l. (1897),
i. p. 1155. Also in Proc. Koy. Soc, Lond., vol. Ixi (1897), \>p. 73-76.
:(->
;s«u'
«ROUPIN({ AND rilAININO TOGKTIIKK OF NKUROXES. (',33
Tr.fr. nu.B
-^r ^ KX[.
Fit;. Uri. — Hori/dntiil sfctiim tlirciiifili tlic iiudiiUii, imtis. and niiilliraiii of a iu'W-
Imrii liabc. WiiHcii-I'al staiiiiiiK- I.rvrl of dmsal iiail of cnrims trapfzoi-
ilcimi and dorsal piirtion id' niuli'iis uliv.uis inl't rim-. « Sciics iii, scctinn No.
1~~. ) ^.^, (•oriiii> Irapczoidciim ; Pre. Hr.Cdiij., dccussitio liracliii conjunclivi ;
Ihr.Iliclit.. coniiiiissiirc lii'twccii liiclilcrcw's miclci ; Ji.i-.ii.r.. dorsal <'a]i.siilc
ot'niKdciis liitiir: F.a.i.. tiliiii' aniiata' iiilnna' : I'lisc. rclmf., t'asciciilus rctro-
*1 M *:. » ' ; . i\. ..:....].. . i :. ...i :.... K. i;..'i:... i' / .. i ii..
fli'Xils Mcyiiciti ; I'.i.in.. fasciculus lont:ilii<linalis nicdialis ; I'.l.p.. liimdlc
coutiiiiioiis with tlif fasci< iilus lateralis innpriiis of tlic cord ; F.l.j).' <h. doi-sal
I)ortioii cd' bundle continuous with fasciculus lateralis proi)rius td' the cord;
I.. I., lemniscus lateralis; /,./»., leiuniscus nicdialis: .V. ///., '"kHx \. ociilo-
niotorii ; X.Mnt.l'.. niotur root of N. trij,'einiuns ; A. I'., sensory root of N.
tri;;cniinus ; .V. 17.. radix N. ahduceiitis ; .V. 17/.. nidix N. facialis, jiars su-
<'Unda ; .V. irst., \-m\\\ N. vcstihuli ; .V. .\7.. nidix N. aecessorii ; .V.A7/.. radix
N. liypoi;lossi ; Xii.l\l.iii.. nuidciis fasciculi lonyitudinalis nieilialis. or nu-
cleus coniinisslira' posterioris •iilicvvr Ociiliiniiiliniii.ik'i'ni of l)arks( hewit.scli ;
Xit.ii.rif.iti., pars iinpar of nucleus N. ix'uloniotorii ; A'». ».///./.. pars lateralis
of lUKdcus N. cpculoinotorii ; A". (/..•*.. nucleus olivaris sujieriov ; A'".fi.c. l'.,
nu(d<'Us N. cochleie ventralis; Xii.i}.!.. nu<'leus idivaris inferior; Xii.o.n.m.,
nucleus (divaris iL<'cessorius nicdialis; Tr.fr.nii.I).. tract from Deiters' nucdetls
to the s])iiial cord, i Preparation hy Dr. Jolm Hewets(ui. i
42
\
i^
I
m
\ll.
'>^
t
jj.--
IJ
684
TIIK NKKVOl'S SVSTKM.
OUOUIMNO AN'U CIIAININCS ToOKTIIKH ol" NKl'lUiN'KS. »;35
culiln'c iiiitl (IfVdid, iir almost devoid, of collaterals. 'I'lie exact,
eoiirses wliieli tlioy follow iint Htill not ctitircly Hcttled, Imt ut
any rate, eoiieerniii^,' certain groups of axoiu'H, we now poHsess
Kid. 417.— Tniiisvcrsc scrtioii tlimiiKli llic ili(>ml)ciicriil!iiloti of ii inmisc at tliu
Ii'vclof Diilcrs' iiiu'ltiis Mild llic cdriiii^ tra|pi/(ii(liiiiii. .MlciS. IImiik'hi y
Cajiil, licit mc /.mil Stiidimii dcr Mcdiillii OhlniiKata. etc., i'.ic^lcr, l.iip/..,
ISlIti, S. 1(», V\fi. :i.) .(, I'asciciiliis liinu'itiidiiialis niidialis; II. r.idix N.
liicialis fjciiii iiiliTiiiiiii : f ', (Rutussiiiiialis N. tii;;<iiiini : /'.radix N. larialis;
/'.'. li.vniiiiis : /•', nirpii.s tnipcznidciiiii ; (,'. iiiiclriis N. ((icliicu' vtiitralis; //.
corpus rcstiforiiic : /„ fiaiit cells of siilistaiitia Kclatiimsi of N. lri),'ciiiiiiiis ;
.V, ciilialci-als t'niiii axuiicsdl' fasciciilus Idiijiitiidinalis iiicdialis; .V. rajilic ;
/', vertical path fiiniicd liy ii.xiiiics nt' iiiichi tcriiiiiialcs c(iiiiicctcd willi the
N. I', 17//, IX, and .V: A', tenninal axciiies (if ccirpiis trapcznideiiiii ; c.
axdiies IVdiii cells ill the iiiicleiis N. ciiclilcie dorsalis; .). nucleus N. vestiliuli
latenilis I Deitersi ; w. a.xdiies rnini cells in Deiters' nucleus: «. a.xiines I'niin
cidls in siihslantia K<'latiu(isii.
>••*
-T
■'■
(iofinito information. Huis it is known tliat a V.iv^o nnniher of
the axones pass dor.salward throu^'h the nuek ns nervi vestib-
uli superior (von liecditerew) and througli the braehium eon-
junctivuni into the cerebellum. These end in the gray masses
1 1
(;:{«;
TIIH NKUVors SYSTKM.
sitimtcd in the nidf <>l' llii' toiirtli vi'iitridc (chictly in \\w mi-
cU'iirt fasli;,'ii, but possibly also in tlu- iiuclciis jfloltosuc: ami
mirleus i'nil)olit'(»nnis) of the sanm side and of tlii' oppositi' sidi' —
mainly, it would scum, in the latter. Kvery one who lias studied
serial sections of the new-horn hahe's medulla and (M'rehellum
must have been impressed by the bands of nieilullate(l liliros
which obviously extend between the nuclei of the roof and the
re«,Mon of Deiters' nucleus (Fig. 410). Now, while the nuijority,
perha])s, of invest i;rators re<,'ard these bundles as medullated
axones arising,' from cells situati'd in the nuclei of the roof and
yk(H/i.r .\./<icMi»(uenu inteinitm).
Cori»ni refti-
""'""■ -' idl
A'i(i7i'i(M .V. I'i'x- _-- ' '
y,irlrii.H .V. r.'». _ i -/-JWyllU
t/hiiti liitrritlU T"^ n^rmi >
( Ihiti-in). I
iV. vi'ntihuli.
XuilriiK .V. n)t7i-
liii- iltirHaliH.
l>lllH(ll Cl'lltltll
ftiitli fniiii the
tiui'Ifitx X.
tfiilis.
Xiiilfiin X.
Cdihliif nil-
tnili.t.
Triirtim sjiindliH N.
Iriyemini. Xurletu
X. fiiciiilia.
liutitllf from (h'<' viirleiix
rufirr lit till' funiculus
lateral in.
Tract from
7>»>i7>'rs" miclt'ux^
to the funiculus laternlis
I'"l(i. lis. — ()l)li(|U(' sccti<iii tlirdiifili tlic l>r;iin stem of a iicwIkpiii cMt. The coiirst'
of till' path I'rnm tlu' imclciis nci-vi vcstihiili lateralis ( Dcilc is ' to tlif i-ciiiaiiis
(if tile vciilni-latinil I'liiiiciili is illwslralc(l. i Al'lcr II. Meld, Aliliaiiili. il.
iiiatli.-|ili,vs. (1. (I. k. ISiii'hs. (icscllscli. d. Wissciisi'ii., Lcip/.. liil. xviii. No. (i,
lSitL>. Tat', ii. FiK. S.)
passing to Deiters' nucleus of the opposite side, still von KoUi-
ker's studies by the method of Golgi show clearly that a part
of these fibres represent axones passing in the opposite direc-
tion, having their ,)rigin in the cells of Deiters' nucleus.
"'h
(JHoriMNM} AND ( ll.\l\IN(J T()(iKTIIi:U ul' NKllfoNKS. r.37
Tlu' nmjority of the iixitiics from Hcitcrs' mirlcus do not,
howt'ViT, piiHrt into till' ('('rchi'lliiin, hut, to;;i'tlu'r witli tlu'
axnn(>8 from the nucleus iiervi vestiltuli superior, juiss niedial-
wiinl, ill order to reach certiiiii htn^itudimil l)un(Ues of llliref; to
he iinniediatcly (h-scriheil. The tihres pussiiij^ nieduilwanl inuy
he divided into two t^'roups: (l)tliose more ihtrsal'.y situated,
and (») tiiose passinj; more ventralward. 'I'iie former ^^roup of
tihres, us Uamnii y C'ajal descrihes them in the mouse, pass
from Deiters' nucU'Us medialward, avoi(liii<f tiie knee of the
facial nerve; they j^o sometimes iK-hintl, sometimes throu<,di the
nucleus ncrvi ahducentis, cross the raphe, and enti-r the fascic-
ulus lonfjitudinalis medialis, where they hifurcateinto an aseend-
injj and descendin<( liml), the former often heini^ the stouter
(KifJ- -^l^)- This "• mc(lial (»r crossed central vcstihular i)ath,"
Kamnii y Cajal tiiinks, is the principal c(»nstitucnt of the fascic-
ulus lonf^itutlinalis meclialis. The second jjroup of fll)res pass-
inj:; to a more ventral and lateral position has heen seen and
studied hy several neurolof^ists. Thus Hruce * saw and pictured
it as early as 1SS!>, and the hundle is indicated in Fij;. 1")(), paf,'c
;{S-^, of Ohersteiner's text-hook puhlishcd in ISiC^'. The hundle
was carefully described by Held f in IHDl and in 1H(I;2, and I
have for illustration reproduced one of the pictures accom})any-
inj,' his articles (Fifj. 4 IS). The axones fjoinj; into this hundle
have heen studied hy (iol<ji's method, especially hy von \n\-
liker and hy Ramon y Cajal. It nuiy correspond to Ramon y
Cajal's "lateral or direct central vestibular path " (Fig. 4Ut)-
Having reached the bundle (which, as the figures show, is situ-
ated laterally as regards the root fibres of the nervus abducens,
and dorso-medially as regards the superior olive), the fibres turn
in it to assume a longitudinal direction. Some, probably the
majority, turn down toward the spinal cord ; others turn up to
run toward the midbrain, while still others bifurcate, one branch
turjiing upward, the other dov/nward into the fasciculi ])ro)>rii
of the spinal cord (Held), and in all ]»robability come into ana-
tomical relations with the cell bodies and dendrites of the lower
* Bruce. A. On the roiim'ctions of the bifcridr Olivary Body. Proc.
Roy. Soc. Edinl). (1889-'!»0). IHitl. vol. xvii. pp. 2;i-27.
t Ilekl, H. Die cent ralen Bahnen des Nervus aousticns bei der Katze.
Arch. f. Anat. u. Physiol., Anat. Ahth., Leipz. (1801). S. 271-'J!)1.— Die
Bt'/.iohuiigeu des Vorderscitensf ranges zu Bahnen im Mittelhirn, Abhandl.
d. k, Siichs. Gesellsch. d. Wissensoh., Lcii)z., Bd. xviii (1892).
ininn
rt|
^!
Hm
i f
:t
G3S
TllK NKIIVOUS SYSTKM.
motor lunironos situiitod in tlie vcntnil horns. 'I'lio Ijuiidhi
niiirked Tr.fr.iin.lK in the iic('oni})iinyin<f illustration ro})r(v
senta tho system under description (Fig. 4;i()).* This vestibular
Kl(i. nil. — Triiiisvcrsc stM'tioii tlirotifin Dfiti'i's' iiticlciis dI'ii iiioiiscii few diiys did.
i.M'lcrS. Kuiiic'iii y Ca.iiil. liciti'MH /.imi Stiiilimn dcr Mcdiillii ()l)l(iiif;;ita, t'tc,
IJrcslcr. Lcipz.. ISlKi. S. r.!», !•"!«. l!l. ) .1, miclius N. vt'.stiluili lateralis
( Dcitcr.s' 1 ; //, iiiiclius N. vcstilmli iiicilialis ; (\ tracliis spinalis N. IriKcmiiii ;
/'. corpus ri'slifonni' ; E. radix iicrvi facialis, pars scciiiida ; ^i'. slnituin
Krisciiin ccnlnilc ; /•', N. vcslilmli : ((, cells id' siilistaiitia Kelaliiiusa cif N. trineni-
iiius ; h, lateral central vest ihn lav path ; il. central vestii)ulaf path reach inu the
niplie ; c, Kcnu inlcniuni i Had. N. I'acialis' ; f. a.\i>nes Iroin N. vestihuli which
appear tn «(> towai'd the raphe ; i;, <'()llaterals from central vestihular axoues ;
//, liifnr'Mti in of an axone coniinK from Deiters' nucleus; the letter c indi-
cates axone
spintil bundle will be described more fidly iu (Muipters IjVTI to
IjLX. The iiscendiiig fibres of both medial and latend centnil
vestibular paths nuiy be of importance in furthering the tniiis-
* Dcitors' miolpiis thus in fill iirobiibility iTprosonts an important wuv-
station belweon the cerehelliini and the spinal cord. The fact tlialnuiiiy
axones from Doitors' luicjens pass ilown into the venlro-hiteral ffi-ound
binidle thiubtlcss explains the intercstitif; ohservalion (d' Holler, win) found
that tho cells of Deiters' nucleus alropliieci after section of the upper cer-
vical cord.
(iKorriNC AND CUAININCJ TOCJHTIIKK OF NKl'liUXKS. 039
Ku.cs.CU
Dec.Bech.1
t.i 1. - ■■* ■ />T' /-'f.( ■ . ■■■' ■ , -^ i'-'^
Jutil
lb)
A'uc.s.(l)
!J\'.uc.s(.m)
i''-'V'i4^^
^ / ^^ 'Mit? ■ ■■it if^
.- llu.r.t.
Nuc,
Nu
Tr.fr.
N.Yll
N.Yesl,
NunH
■N.Yl.
N.XI
V
I.c.to.F.r.
Fki. t~(l. Iliirixiiiital section tliroiiKli tlii' iiiiiliilla. pons, and niidliniin of a new-
tiorii IkiIic. WciKfit-l'al sliiiliiiij;. Level nl' (leeus.sali() liniehii eoiijuiielivi
ami 111' llllclills reliclllaiis tryiilellli. (Series iii. seetiiin Nil. Ids.) C.y).,
eoimnissiira |icislericir eeieliri : Ihr. Il.r.. ilei-iissatin liiaeliii eipiijiinetivi :
l>cc. Hiclil.. eiiliilllisslire lielweeli I'.eelilerew's lUlelei : D.t.. lilires tii (ieellssalio
te-iiiieiiti ; F.ii.i. Cini. '.. liliiie ai'eiiMla' iiiterie.e lidin llie imcleii.-^ t'imieiili
euiieali: /•'.(•., I'aseieullis eiiiU'alils : I'.r. In I'.r.. Imnille IVniii faseiciiliis
euiiealus tci ritniiadd relii-iilai'is : /•'.(/.. t'iiseieiilus unieilis; r.l.tii.. taseieiiliis
loiiuiliiiliiiMJis iiiiilialis ; I. .in., leimiiseiis iiiedialis : /,./,, lemiiiseus iateralis;
.Mnl.r.. niilix luiplDriiis \. ti'ifieiniiii : .V. 17/., radix N. facialis, pars seeimda;
.V.ic.v/., radix N. vestiluili : .V.I7., radix N. alidiiceiilis ; .V.A7/.. radix N.
Iiypdjildssi ; .V..\7.. radix \. accessurii : .V». ».///.( n ), inicleiis N. ciculdiiuptiirii.
pars lateralis: .Vd. ii. ///.7/ 1. iiiicleiis N. nciilumntorii. pars iiiipar ; Xii.r.x.il •,
tiilcdi'iis centralis superior, pars lateralis: \ii.r..i.' ni). nucliiis centralis
siiperiiir, pars ineilialis : .\ii.l.l.. iiin lens lenmisci lateralis: .\ii.ii. 17/.. nncleu.-*
N. I'aeialis; .V»..V,r.r.. nucleus N. cochlea' venlralis: .V//. (•.(., nucleus cen-
tralis interior : .S'n.r.l.. nuilens ret icularis lej;nunti : .\ii.l.-i.. nucleus lateralis
superior; Sl.iir.c, stratum K'iseum ccnirale: .Sh.I'.. sensory root of N.
trigeminus: >'.<;., sulistantia Kclalinosa Ivolandi ; 'I'r.fr.iiii.D.. tract from
l);iti'rs' nucleus to tile spinal cord: T.s.n.l'., tr.U'tus spinalis N. triKcniini.
Preparation hy Dr. .lolin llewetson.i
V
mmm
'
\
040
THE NERVOUS SYSTEM.
port of impulses toward the cerebral cortex ; if so, they are prop-
erly regarded as axones of sensory neurones of the second order
in the general path from the periphery of the body to the sonues-
thetic area of the cortex. The exact course of the ascending
i^lires is not wholly clear; those of tlie medial path accompany
the fibres of the fasciculus longitudinalis medialis ; * iiuleed, if
Kamon y Cajal be right, they make up a large part of this
bundle ; those of the lateral bunille either join the lemniscus
medialis or run u}) as a separate bundle in the formatio reticu.
laris, some of them ultimately, in all probability, passing through
the tegmentum of the cerebral peduncle into the diencephalon.
* The affert'iit vestibular inipulses in the faseicuhis loiigitiulinalis me-
dialis prubaljly exercise a coiitrollinjj; etl'ect upon tiie eye muscle nuclei. In
vestibular disease a peculiar form of nystagmus is nut infrequently met
with.
V
I I
hit
CHAPTER XLV.
CENTKAL CEXTRIl'KTAL TKKi E.MIXA L XKLKOXHS.
The substantia jiolatiiiosa and nuclei tractus spinalis iiervi trip'Uiini — Inter-
stitial cells — Marj^inal cells — Deep or medial cells — The giant cells —
Axones and collaterals of central trigeminal neurones.
Thk coll bodies and dendrites of the sensory neurones of the
second order pertaining to the sensory part of tlie nekvis
THKiKMixus are situated in the substantia gelatinosa and adja-
cent gray matter. The substantia gelatinosa adjacent to the
tractu? spinalis nervi trigemini may, therefore, be called the
iiurh'i tractus spinalis nerri tri(/c/tiiiii. The large mass of
substantia gelatinosa situated oi)posite to and somewhat above
the entrance of the nerve, often referred to as the main sensory
nucleus terminalis of the trigeminus, is really only an expatuled
upper extremity of the substantia gelatinosa, which accom-
panies the tractus spinalis, inasmuch as serial sections show
that these masses are directly continuous with one another. A
portion of this large main mass of the anterior extremity of the
nucleus is intercalated between the motor and sensory bundles,
and is possibly destined to receive the ascending limbs of bifur-
cation of the entering sensory axones.
These terminal nuclei of the sensory trigeminus have been
studied especially by von Kolliker* and by Ramon y Cajal.f
According to von Kolliker, the cells may be divided into two
kinds: (1) large cells and (2) small cells. Their axones, he
believes, pass medialward as fibrsv arcuativ interuie, decussate in
the raphe, and turn to run longitudinally, probably in the
medial lemniscus.
Ramon y Cajal's studies concerned chiefly the nuclei in the
* von Kolliker. O/i. cit.. S. 281 fT.
t Hamon y Caj'd, S. HeitraK zum Studium der Medulla Oblongata.
Deutsch von Hresler, I.eipz. (18!»0), S. G IT.
641
W h
Vf
Mil' '
^4.
!
•1 ■
C42
'I'llH NKIiVorS SYSTKM.
moiuii'. Ill' (liviik's tin- cells of the sensory micleus into tlireo
zones: (1) tlie interstitial cells, {'i) the nuirffinal cells (littiitl-
zellen), and (;{) tin deej) or medial cells. The interstitial cells
are trian<,Mdar or stellate, sometimes spindle-shaped. Tliey are
located between the bundles of the deep layer (/'/VA' .s-/////v^ p.
ry'i'l) of the traetns spinalis or between this and the supi-rlicial
layer. Their dendrites pass ventrally, dorsally, or medially in
amon<; the l)un<lles mentioned. Their axones assume usually
a !onf::itudinal direction either in the adjoiniiiLr bundles of the
traclus spinalis or in the sui)stantia fj^elatinosa itself. The cells
are nearly of medium size, althoujjjh many of them reach con-
siderable dimensions ( Fi^. 4'21, ^0-
The marj^inal cells form a thin layer just medial to the bun-
dles of the deep layer of the tractus spinalis. Many of them
are spindle-shaped, others are pear-slia])e<l, the demlrites assum-
ing variable directions. The axones run in ])art ventralward,
giving off collaterals to the substantia gelatinosa and being con-
tintu'd as longitudinal fibres of i\w phaniDi Jilirilldrc iinifim-
didii, in part medialward, in order to help in the formation of
the central sensory path.
The deep or medial cells, those of the substantia gclatinosa
proper, are very numerous. In shape they are usually triangu-
lar or stellate, and caji be divided into giant cells and small
cells. The latter are the more numi'rous and are arranged
chiefly in the form of sjuall, sometimes indistinctly limited,
islands. These ishmds, which appi'ar never to be absent from
the dorsal region of the substantia gclatinosa, consist of three
elements: (1) N'ery finely branched varicose dendrites, arising
from the spiiulle-shaped or triangular cells and lying in the in-
terspaces between the islands; ('^*) extremely complicated den-
drites, which have their origin in the small cell bodies lying
within the cell islands; (;{) a numb(>r of very dense plexuses
nuule up of the end ramifications of collaterals or terminals
from the axones of tlu' tractus spinalis nervi trigemini. The
very delicate axis cylinders of the small cells of the islands give
off branched collaterals in the substantia gclatinosa and follow
an irregular course, so that Kanion y Cajal could rarely follow
them Ijcyond the substantia gclatinosa itself. Occasionally,
however, he saw one reach the formatio reticularis grisea, and
he assumes that such axones perhaps enter the central sensory
path. __ , .
u
3?r
CJUoriMNC AND CHAINING 'HXJ 1-71" 1 1 Kit OF XKCUONKS. (;4;{
'JMio jifiiuit cells nrv .scattered irref^ulurly tlirouj^li the whole
sub.staiitiii <,'('liitiiiosa ; the axoiies from these cells could 1)e
easily and certainly followed. Arising ordinarily from a den-
Fid. 421. — Tr;msv('rs(> si'ctiim lliniii!.'li the tractiis spinalis N. trifri'inini iiiid
ailjiici'iit siilistimtia j,"'latiii(isa ula luwiiorii raliliit. i Al'lif S. Haiiiun yCa.jal,
Hi'itrafi /.iiiii Sliidiniii dir Medulla ( (lildiiuata, etc., lirrslrr, Lcipz.. ISiMi. S. M,
Fij;. 2.) .1. Ventral part nl' tra<'tiis spinalis ; n. interstitial cells: c. niar^rinal
ct'lls ; i\, vi'W islands in siilistantia tiejatinnsa : c, small eells of tliise islands ;
/.stellate tiiant eells not arranjied in islands; (/, interinsular cells; h.w.
marginal cell, the axiine ef wliicli appeal's to Ko into the white snhstance or
into till' traetus siiinalis N. tri(;eniini.
m-
\
s
il«.
li'
.;■!'
:f!
ft'^
J"
l'*'5»5'WK.(
644
TFIK NKRVOUS SYSTHM.
tlriti' ni'iir tlic cell Ixidy, sucli an axuiic turns dorsally and me-
dially in the form ol' a curve, f^ivin;; olT two or more eollatei-als
to the substantia f,'elatinosa and to the formatio retieularis
fjrisea ; it is continued linally after Iiavin<f crossed tlie dorsal
2)art of the rajdie at a level which varies for dilTerent axones, as
a h)n<fitudinal ascendin<,' fi])ro of the medial lemniscus of tlio
oi)i)osito side. The fibre often ])ifureates into an iiscending and
a descending' liiiih.
'i'lu! axones of otiier ^nant cells do not cross the middle line,
but, havin<,' arrived at the dorsal border of the formatio ri'ticu-
laris grisea, l)en(l arouml in the neighborhood of the knee of
the nervuH facialis to run in a longitudinal bundle. This ])un-
dle, representing one central path of the trigeminus, receives
axones not only from the substantia gelatinosa of the same side,
but also from that of theo})})osite side. According to Kamon y
Cajal, it finds a special location in the formatio reticularis alba,
close to the central longitudinal path, made up of the axones
of sensory neurones of the second order associated with the
nervus vagus and nervus glossopharyngeus.
Other axones from the substantia gelatinosa may follow a
still different course, but for the details the reader is referred
to the original contribution of Ramon y Cajal. All important,
however, is tlu' observation that the axones of the central neu-
rones now under description, in their transverse as well as in
their longitudinal course, give ofi' collaterals into tlie formatio
reticularis grisea and alba, some of which certainly reach the
motor nuclei, in which are situated the cell bodies and dendrites
of the lower motor neuroiu's, the axones of which go to make
up the nervus facialis and the motor part of the nervus vagus
and nervns glossopharyngeus. In Fig. -122 are shown some of
the fibres of the trigeminal path entering the bundle continu-
ous with the ventro-lateral funiculi of the cord.
While many of the axones of the central neurones just de-
scribed are coiu-erned in more or less complex refiex acttivities,
certaiidy some of them, either directly, or iiulirectly by means
of neurones of a higher order, take ])art in the formation of the
longitudijial bundles which go through the tegmentum of the
cerebral i)e(luncle into the henusphere.
The two human cases reported by Iloesel * make it seem
* Op. fit.. Chapter xlvii. _
id
Hi
CillOUl'lNO AND CIIAINIXCJ T()(JKT11KR OF NKUHON'KS. r.45
• 'ji m
\\
li
.'V!
(;4(;
TlIK NFKVors SYSTK.M.
likely timt tlie ci'iitnil trif,'oiuiiiul (•(Hiduction path is a crossed
path tcniiiiialiiijf in the central jryri of the pallium. The indi-
cations are that it is interrupted in the ventro-lateral f^roiip of
nuclei of the thalanius. If this he the case, then in the tri<^ern-
inal conduction paths at least three neurone systems are super-
imposed, the crossinf( takin;; place in the domain of the system
of the secoiul order. This view has heen c()ntirine<l by the ex-
periments of \\ allenberg.* After injury to the substantia fjela-
tinosa in the upper cervical cord on one side, he found dcf^enera-
tion of a bundle of fibres which crossed the raphe ventral to the
iiuclcJis N. hyp(i<i[lossi, and then asceiuleil in the formatio re-
ticularis, beinjf at first situated medio-dorsally and higher up
latero-dorsally. Having reached the level of the hilus thalami
the fibres entered the lamina uu'dullaris medialis, and a large
part of them ended in tlui ventral group of nuclei of the thala-
mus. Another group of degenerated fibres could be followed
by Walleidjerg across the ra})lu', thence by way of the inter-
olivary layer and medial lemniscus to the ventral part of the
thalamus.
* VViillonberg, A. Zur seoundiTren Bahn des sensibk'ns Trigeminus.
Aimt. All/.., .Jena, IM. xii (IbUO), S. !)r)-110.
•i)i 1
u u
3. Central Neurones, the Perikaryons and Dendrites of which are situated in the
Cerebellum, the Axones running Cerebralward, and possibly representing
Indirect Central Centripetal Conduction Paths.
("IIAl'TEU XLVI.
TIIK SOM.I^STHKTIC I'ATII TO TlIK (I'.KKHUr.M IIV WAV OK TlIK
CKKKUKLLl'M.
I'eri'bell )-ccr(>hriil paths — 'i'lic bracliiuiii (•(njiiiictiviim or sii|)('rior eercbclliir
|i('(luiivle — KxpcriiiK'iital (li'^'i'iicnitioiis — Dcfieiicnilions in liuiiiaii cases
— Mycliniziitioii of the Ijniciiitim coiijiiiicliviiiii — Studies by (iolgi's
nictlioil — TliL' fasciciiliis ecri'lwiiuris lateralis (loscendeiis.
Takino ii backward fi^lance for a moment, it will be seen that
from all tlie groups of sensory neurones of the second order,
pertaining to the spinal and cerebral nerves which bring im-
pulses concerning the body itself iiito the central nervous sys-
tem, there are axones (aside from those of slujrt paths mediat-
ing rertexes) passing in two nuiin directions: (a) toward the
cerebral hemisphere by way of the tegmentum of the cerebral
peduncle ; (h) into the cerebellum. Of the former, the groups
of axones going to make up the medial lemniscus, the fascicu-
lus longitudinalis medialis, and certain longitudinal bundles in
the formatio reticularis will be recalled ; of the latter will be
remembered the fasciculus spino-cerebellaris dorso-lateralis or
direct cerebellar tract of Flechsig, the cerebellopetal systems
in the fasciculus ventro-lateralis (Cowersi), the fibnv arcuata'
exterme ventrales et dorsales pertaining to the spinal paths, as
well as certain less defitiitely worked out cerebellar connections
of the nuclei of termination of the nerves of the rhomben-
cephalon. Further must be mentioned the fact that from
many of the axones from the nuclei of the dorsal funiculi, as
they pass through the stratum interolivari lemnisci, there are
given off collaterals to the nucleus olivaris inferior. Thence
the cerebellum may be influenced by the fibrai olivocerebellares.
647
ilH¥
f
'I
-■ ■ \
,:
!■
-=^
<)48
TlIK NKUVOl'S SVSTKM.
Tho qui'stion mitiinilly arises, Ciin those nerve fll)r('s, which
run in to terniinnte in tlie ^^riiy mutter of the cerehelhnn, help
to carry impulses towanl the cerebral cortex i)y means of neu-
rones of a hif^'her order? That they can do so seems fairly
Fi(i. 423. — Horizontal section of tlic cfrchclliini jiassinf; tliroiifjli tlif iiiiirHinal
tlii(ki'nini;s of tlic liiitiula. (AftiT H. Stilling. Xciif I'litcrsui'li. ii. (1. Han
(I. klciiicn (ii'liirns d. Mciiscli., Casscl, ISTs, Taf xv, Fin. !is, taiitii fnaii
.1. llcnh', Ilandliucli dcr .Vcrvciilclirc dcs Mcnsclicii. II. .\iill.. Hniiinsdi.,
lH7!t. S. ^;,')!». V\ii. ITS.) ('c<i, liracliiiini cDiijiMictiviini ; dl. niifitus dtiitatiis ;
.1', luiclfiis ciiilioliforniis ; //,//, i)arts of tlu' nucleus n'ol'osus ; i, nucliiis
fastijjii.
certain, partly from clinical evidence that need not now he
discussed, and partly from anatomical findings to be imme-
diately mentioned. We have seen that the axones entering the
cei'ebellum from the nnclei of termination of the sensory nerves
do so chiefly by Avay of the corpus restifornie (inferior cerel)ellar
peduncle) ; a few of them enter by way of the brachium con-
OUori'IXd ANI) CHAIXINd TtKJKTllKll Ol' NHrUONKS. <;4'J
juiu'tiviim (superior ccrclx'lliir pcdiiiiclc) ami vchmi nicduUarc
aiitt'rius (for exam pic, a part of (iowcrs' tract), and a few possilily
tlirou^'li the bnicliiiim poiitis (middle cerebellar pedmicle).
Theses uxoiies terminate cliiclly in the cortex of the vermis;
some terminals as well as many collaterals j^o directly to the
nuckuus deiitatus, otiiers to tiie nuclei fastij^ii and adjacent
masses of ;^'ray nnitter. ('I'lie ^n-oss relations of these nuclei to
one another are shown in Fig. 4'i'.l) There is evidtMu-e, further,
tiiat the nuclei dentati and nuclei of the roof ire manifoldly
fat y
filTTT
Fl(f. 4^4. PiO't of a triMisvcrsf scctiini tliriiiijjii tlic cfrfticllinn anil inciliilla
olilontiala of a limiiaii tniUryii 14 cm. Ihiik; staining tiy WciKcrt'.s iihIIkmI.
lAt'tiT W. villi liiclitcrcw. Die LiiliiiiKslialiiuii iiii (iiliirii iiiiil IJiirkfiimark.
Dcutstli von H. W.inli.iK. II. .\iill.. I,.i|.z., IS'lit, S. :5!»5, I'if,'. 372. i rit,
niiclt'iis (Icntatiis ; fin. niiclfii.-i cinliolironnis ; nil, nncli'iis k1ii1io>iis ; iit. iiiiclt'ii.s
t'astiKii ; ' ■ I'mti'x of vcnni.s; fil. ilorsal, fm. niiddli', fi\ ventral Imndlc of"
lii-acliiiiin (•onjiini'tivniii ; iiVIII. niiclcns N. v('stil)nli sn|icnor ; fiil'Ill,
lilircs (•xltiiiliiiK tirtwi'iii till' iiinlius N. vrstitiuli sniinior anil tlif niulins
X. vi'stilmli latinilis on tlir one lianil anil tlic nnclii of tlir riiflicllniii
(l■^|n•^•iall.v till' niirli'Us jiloliosiis anil tlir nnrliiis cnilmliforinis ' on tlir otlior ;
ffij. tiln-i'sof till' corims ri'stifornir fioin the niirlins fnniriili ^'larilis liy way
oi" till' tilira- aicuatii' rxlrrna' Vfiitrales; /ni. non-incilnilatiil lilinc rciilu'ljo-
olivari's ; /<c, lilircs in ior|iiis rcslifornif nirnspoiiilinf; to > 1 i the laMiriiliis
siiinorcrclH'llaris ilorso-latcraiis, '2' the litirrs from the niirli'iis fiinirnli
cuiicati, anil iIJ) tlio liln'rs from the ninlii fiinieiili lateralis ;/<«, li;iiiil of
(ihres froiii the iinelei fastijtii to the iiiiileiis olivaris siiperior ami to the
niieleiis N. vestiliiili lati i-alis (of Deiter.s ' : fiil. tihie.s (•iinneetiiiK the nneleiis
fastiKii anil the cortex of the vermis; fnii. liln-es coiinectiiiK the miclens
filiilmsiis ami the imcleiis emiioliformis with the cortex of the worm.
• !|
connected by means of tissociative neurones with the gray mat-
ter of the cortex of the vermis (Kigs. 4:?+ and 4"^o).
43
r'r
650
TIIK NKHVOUS HYSTKM.
(iivcii (lit'Hc (Mmdilioiis, it is not dillii'iilt to find an iinntonii-
ciil path wliitli could serve for the further conduction of sen-
XII Ail\
Nuoj Nuoam
l''l(i. ■J'jr).--Triiiisv('isc sfctiiiii III" int'diilla iil)l()HKiilii mikI im rclH'llimi of iicwlmrn
child. IScrifs ii, sci'linii Nn. lid. i r.c, i (nims rcslirciniic ( (lie pint iiiiilul-
lalcd ciirrcsiidiKls in tlic iiiMiii to the dircrl tcnlicllnr Iniit): /•'./., hiindli-
ciintiniHPiis with the fimicliliis lali riilis nf liiccord; l-'.l.ni.. rascicilllls IihikI-
tlidiiiiilis iiii'diiili.s; .V. /.V. A'., N. KliissiipliiiiyiiKcijs el vajilis : .V..\7/.. N. Ii.v|iii-
Kidssiis; Sii.il.. iiiiilfiis diiiliilils ; .\ii.ii.i\<l.. iiilclcils N. niclilcii' dorsiilis
show M iiiiprc l.viiieiill.v on (ip|i(isilc si<li' (pC limine ; Sii.ii.r.in.. nucliiis N. vrs-
liliiili nicdiiilis : \ii.ii.ii.<l.. nnclciis oliviiiis iirccssurins dmsalis: Sii.d.ii.iii.,
imrlcns iilivaiis acccssurins nicdialis; .\ii.i).i., niiclciis nliviiris inferior;
Sii.l.s., nurlcus tnutns solilaiii : /'../'., pt'dnnculiis lloccnli; /'//., pyniniis:
li.il.ii.iisl.. iiidix disccndcns N. visliliuli: .""7.(./., slialuni intcrolivarc Icni-
nisci ; Hii, plane of lon};ilndinal section No. l!(>. [Nnii;. — This linure has
licen dispi'opoi'tionalely rednceil in (he reproduction.]
sory inijiulsea cereltrahvard The axones of this ])ath * consti-
tute tiie main ])()rtioii of the brachiuni conjunctivuni f (Kifjjs.
4S>() and 4t>7).
The study of defionorations in patlioloj^ncal eases in luunan
beinjjs (Turner, v. Monakow, Turner and Charcot), and after
experijnentiil section of tlie brachiuni conjunctivuni in aui-
* Van (toliU''htoii's I'otV cfri'hdlo-cervbrale.
\ The bnu'iiiiiin conjunct iviiin wiis first picttirod liy Tjpvoillc. It was
carefully described by Stillinj; us the procvssus ciri'/wl/i ad cerebrum. Slil-
ling's picture is rc[iroducod in b'ig. 428. In Hnglish books it is usiudly re-
ferred to as the superior cerebellar peduncle.
fi
A U j*_
(il^(»l•|M^■(} AND CIlAININd TocjKTlir.lt OF NHIIJONKS. r..M
nulls,* Imvi' UmI to ri'sultH wludi liiivc liccii iiitcrprctcil in dilTcr-
j'tit ways. Thcrr is aldiiKlinitc of cvitlciicc to show the iiitcr-
licpciiilcMcc of one ccrfhriil liciuisplicrc iiitd tlw oppositf ('crc-
liclliir lit'iiiisplicrc (I) l>y wiiy ol' tlic hriicliiurn oiijiiii(ti\ iiin, and
["i) by way of tlio bracliium pontis. Tliut Ihc conncctioii is
Fi«. 42(t. Tnuisvi'rso section tlirouf;!! istliimis riMiinlH'iiccpliitIi dI" iH'wlioni
l)iiln'. I \VciK<'i't-l'iil, scrirs ii, section No. Ms.) Ilr.rinij., linichiimi coii-
jiincliviini ; ''./., collicnhis iiiltrior ; y. 'I'iclcus dcscrilicd liy Wtstplial as
prolciMy coni'crncd in the ori;,'in of the N. troclilcaris ; F.I. in., liisciciiliis
lonKitiiilinalis mrclialis; /•'./'//., I'asciculi loiiKitudinalcs [pyraniidalcs] ; /,./.,
lemniscus lateralis: /,./»., leninisens niedialis ; .V. / 1'., decnssilio nervornin
tro( lilearinni ; .V. I'., N. trifjeniitms ; Xii.l.l.. uuclens leninisci lateralis;
A'».(•.^, inicleus reti<'nlaris tcKirienti pontis; H.il.W. radix desceiidens [niesen-
I'l'pliiilica] nervi tri^'cniini. (Preparation l>y Dr. .lolm Ilewetson. i
* Korel. A. Tagebl. der Veriminll. dcr Nutiirf. in Salzbiirg, 1881. Sekt.
xviii.Sitz., Sept. 19. — von Monakow. ('. Sti'iie acustica' iind iinteiv Sclileife.
Areii. f. I'.sychiat. ii. Nerveiikr.. IJeri.. I5cl. xxii (18!Mt). S. 1-2(J.— CruiiHT, A.
Kinseitige Kleiiiliiriiatfopliie iiiit leiciiter atro|)liie der gekretizteii (irf)s.s-
hini-llemisphiirp, nebst einein Heitrag ztir Aiiatomie der Kleitiliinistiele.
Heitr. z. patli. Antit. u. z. allg. I*atii.,.]eiia. I?d. xi (1H!I1). S. :!!»-r)8.— Maliaiin, A.
Kechert'lies .siir la structure aiiatdiiiiiiiu' dii tioyaii rouge et .ses ('oiiiiexions
avec lo |)e<l()!u;ule cerebelleiix siiperieiir. Brux. (18!t4), V. llayez. 44 pp.,
5 pi., 8v(). .Mso in Mem. coiiron. .\ead. de roy. ini'd. de Helg.. Mrnx. (1H'J4).
f. xiii.
■f:
w
S
It
05
r.«>
TIIK NKUVors SVSTKM.
liUoLTlNCi AM> CIIAININU TUUETIIKll oF NKUUONES. r,','.]
lint direct, however, is sliown l)V the fuel thnt. after cdreliriil
h'sidii tlie eliiiii;,'es in the cerehelliir petliiiieh'S (siiperidr iiiid
mi<Mle) iire tliose ul" siiiiph' iitr(i|>iiy riither than (if aetiiai
.seeoiidary tle^M'iieratidii. It I'lirlher ajtpears tliul after exiieri-
l'"lii. l^!S.— Stilliiin's liiiKc 1111(1 siiiali " scissors " ipftlic Imiiii. ' T'lnin A. UuiiIht,
l.ilirliii.li ilci Aiiiituinic dcs Miiiscliin. V. Anil.. !,< i|./„, isns. liil. ii. S. t:)s,
l'"i«. :<s7. ) /. Ilialiiiiiiis : .'. iiiirli'iis nilicr; .;. iiiicliiis ilciitiiliis ciiilMlli ; ;,
liriii'liiiiiii rdiijiiiicliviiiii : '>. Iiiiiiillt' ri'oiii tlic niK'li'iis I'lilirr to tlic |IimImiiiii> ;
>i, iiiiliatiiiii I'i'oiii till' nuioii ul' thi' iiiirliiis niliir In tln' cMpsiihi iiitiiiiii.
iiieiitiil section of, for e\iiiii|ih', the rij^lit lirai'liinin conjimc-
tiviiin, all or nearly all the lilires deffcncrato throuj^h the de-
ciissiition* to the red nndens, and there results not only
alteration in the cells of the nucleus dentatiis and cerehellar
hemisphere on the side of section ( Mahaini), hut also atrophy
t»f the posterior part of the red nucleus of the opposit*' side,
the cells of till' anterior part of the red nucleus and a few
sciittcri'd ci'lls in the posterior part retiuiining intact (Korel,
•i
* Tlie (Iccussftlidii (Iii)rs(>s|it)(> fdiiuiiissiirc ul' Wcriu'kiiick) is siliiali'ii just
vt'iilrnl to till' inriTJor cnlliculus ol' tlic ccirjiiirii (|iiii(lrifjriiiiiiji (l''itt^. 42!) ami
4:10).
14 (
ii;
654
THE NERVOUS SYSTEM.
(Jiuldon, Miiluiim). While sonio authorities believe that the
fibres of the brachium coujuiictivuiii have their origin in
the cerebellum, others think that they originate in those cells
of the red nucleus which atrophy on section of the bi'achiuni
St. gr. c.
St.alb.p.
N.F.
Dpc.Br.Coni
5.n. ^
Fig. 429. — Tniiisvi'rs<' section tlin)ii};li iii('si'nc('i)liiil(Hi of lu'wlioni balii'. Level
of cnlliciili siipcriorcs ol' t'orpoiii (iiiii(lrif,'<'miiia. ( Wcincit-l'iil, scries ii, sec-
tion No. :$;}S.) .!(/. ccc, ii(|iic(iuctii.-. onliii ; /><'(•./(/■. f '«)(,;., dccussiitio bnicliii
coiijiinclivi ; /^^. decnssiitio tctlinciiti ventialis imitnth' lldiihiiiLri'ii^itiifi at
Foril) ; F.I. III., fasciculus lonf,'ilii(linalis nietiialis; F.l'n.. fas<iculi pyraniidales
in the pars l)asilaris pontis; L.iii., Iciruiiscus niedialis: .V./l'., N. Irochlearis ;
yii.t.-i., nucli'us lateralis superior of Klechsij; ; A". »./!'., inulcns .\. trocli-
learis; Sl.alh.i)., stratum all)Uin profunduiu ; >7.(/c.('., stratum Kriseuui cen-
trale ; S.u., subsUmtia nijjra. i I'repanition liy Dr. .loiin llcwetsoii. i
conjunctivum, and that they do not begin in the cerebellum
but end there. The experiments in which one half the
cerebellum has been extirpated * have, on the whole, afforded
* Veja.s, P. E-xpi^rimentelle Meitriige ziir Keiintniss der Verhiddungs-
bahnen dcs Klcinhiriis mid des Verlaufs der Funiculi gruciles uiid cuiieuti.
Arch. f. Psychiiit., etc., Rerl., Hd. xvi (1885). .S. 200-214.— .Mtirohi. V. Des
degenerations consecutives a iVxtirpation totale et partielle du oervelel.
Arcii. ital. de biol.. Turin, t. vii (1886), pp. ;ir)7-:?63.— Mingazzini, G. Sulle
degonera/ioni consecutive alle cstirpazioni eniicerehellari. Uicerche n.
lab. di anal. norm. d. r. Univ. di Hotna, vol. iv(18!)4), pp. 7;i-124. — Ramon y
Cajal, S. Algimas contribiiciones al eonociiniento de los ganglios del encefalo.
"r^"~"*b !
{iIU)UPIN(} AND CIIAIN'IXC} T()(}I*:TIlKli OK NKUItONES. 055
no more exact conclusions, though Miirchi asserts tliat tlio
lihres of the bra(^hium conjiinctivuin do not underj^o complete
decussation, since he can follow a small l)Uiulle, past the region
of crossing, directly to the thalamus of the same side. This
uncrossed bundle of Marchi appears to be reinforced to a slight
extent by the medullated axones of cells situated in the part of
the nucleus ruber designat(^d by Mahaini as the " nucleus mini-
mus " (von liechterew). Ferrier and 'J'urner describe compk^te
degeneration of the brachium conjunctivum after extirpation
of the lateral lobe of the cerebellum.
Von Kijlliker * interprets the findings in the cases of sec-
ondary degeneration above refen-ed to differently than do some
of those who have carried out the experiments. lie believes
that the majority of tlie fibres of the brachium conjunctivum
arise in the cerebellum, run cerebellofugally, and nearly all
undergo decussation ; part of them end in the red nucleus of
the opposite side, especially in its posterior part (that region
which atrophies after section of the brachium conjunctivum);
part, on the other hand, go through the red nucleus, with-
out ending in it, to join the bundle of fibres lateral from it
and to enter the area in the hypothalamic region, known as
Ford's " Feld II," to be referred to later. Held f believes
that the majority of the fibres of the brachium conjuncti-
vum arise in the nucleus dentatus, a view quite in accord
with the observations of Menzel, Arndt, and Dejerine,
which prove that, in lesions of the cerebellum involving only
the cortex and subjacent white matter, no marked altera-
tions in the brachium conjunctivum or in the red nucleus
result.
ii. rtiinf,'lios corohplosns vi. roiicxioiics distantes do los cchilas de Purkiiije.
Analrsdc la Sociedad espaiiola de liistoria natural, Madrid, 1H94. — Ku.ssel,
J. S. U. Depencrations Consequent on Kxiieriniental Lesions of the Cere-
bi'liiim. Pn.c. Hoy. Soo.. Lon.l., vol. Ivi (1Hi)4), j))). mUJO.").— Ferrier. I).,
and \V. A. Turner. A Record of Experiments Illustrative of the Synij)-
toniatology and Degenerations following Lesions of the Cerebellum and its
Peduneles and related Structures in Monkeys. Phil. Tr. Lond. Soc., vol.
clxxxv (1H!)4), P., pp. 71 !)-77H.— Thomas. A. Le cervelet : etude anatomicjue,
clinique et physiologi([ue. 8vo. Paris, 1H!I7.
* Oji. rit., S. 4r)0.
f Meld, A. Hoitriigc zur feineren Anatomic dcs Kleinhirns und des
Ilirnstammes. Arch. f. Anat. u. Physiol., Anat. Abth., Leip/.. (1893), S.
435-446.
1 J'
\
t\
■"-WSBBWRHI
(mO
TIIK NKIIVOUS SYSTEM.
f.,i ■■;!,/
;, 1
Hi
■ I, J
Mu.nl
IIU.C s.aw-*4
■MvK
■Dec.D.c.
A'u.c.s.(l)
, Hot.Y
TrfrnuP.
K.ra
N.Yesl
Nuni
■H.YI.
•. F.a.iXCu4
'^^'^Pm 1:$:
V
Fl<i. 430. lt(iriziiiit;il sci'tiiin tliripiij;!! tlic iiiciliilla. inms, iiml luidliniin ofii ncw-
liipiii liiilif. \Vci>;<Tt-l'iil staining. Lt'Vcl nf (Icciissiilio linicliii cipiijuiutivi
ami lit' niuliiis ifticiilaris tifimi'iiti. ( Si rio iii, Mrtimi NO. los.) f'./).,
tiiiiiiiiissiii'ii |i(isti'riiir <i rcliri ; Ihr.li.r.. dcciissatici Imicliii liPiijuiictivi ;
Ihr.Ilciht.. (■oiiiiiiissurc liflwicii licchtcrcw's iiiiilfi : /)./.. liliiis tn ili'cussatio
tcKiiii'iiti ; F.ii.i.' Ciiii. '.. I'lhoi' arciiata' iiitcnur rrmii the niiclciis ruiiiciili
luiicati : F.C.. tasciciiliis cmii'aliis; I-'.t\ to /•".)•.. liuiidlf tVcpiii rasciciiliis
ciiiicatiis to riiriiiatii( reticularis: /■".(/., fasciciiliis urarilis; /•'./. m.. I'asci<'iiliis
loiiKiliidiiialis irifdialis : /,.»(., Iciimisciis iiicdialis : /,./.. Icinniscus lateralis;
Mot. v., radix iiiiitnriiis N. trijieiniiii : .V. 17/.. radix N. t'aeialis, pars .se<iiiida ;
X.irst., radix N. vesliliiili ; .V. 17.. rsidix N. alidiieeiitis ; S.XII.. radix N.
liypcifjliissi ; .V. A7., r.idix N. accessorii : Sit.ii. II lAu). inieleiis N. (leiildiimtiirii,
liars lateralis; .V».». ///.7/ ). nucleus N. (iculonmtorii. liars inipar ; yii.c.s.it \
nueli'Us ceuli-iilis superior, pars latenilis; yii.c.sj m). nucleus centralis
superior, pai-s niedialis; Xii.l.l., nucleus leumisci lateralis; Sii.ii.l'II.. nucleus
X. facialis; Xii.X.cr., nucleus N. cochlea' veutralis; .Vk. (•.('., nucleus cen-
tralis inferior ; yii.r.t.. lundeus reticularis tcKuicnii ; Xk.I.h.. nucli-us latenilis
superior; Stjir.r., stratum f,'riseiini centrale; Srii.W. sensory root of N.
triKeniiuus ; >'.;;., substaulia jrelatinosa Kolaiidi ; Tr.t'r.iin.l)., Iiiict from
Ueiters' nucleus to the spinal cord; T.s.n.V., tractus spinalis N. tri^eniini.
( Pri'panition liy Dr. John llewetson.;
<i|{()Ul'IN(} AND CllAININd TOOKTIIHI! ()K NKlIioNKS. (\-yJ
In ii case rt'|)()rtc'(l hy von Moiiakow,* in wliicli (hero was a
(U'f(!ct in tlio rif^lit ccrcljral licniisplu'rc, and also a lart^i' dcfoct
in the left cerebellar hemisphere, no marked secondary de<j;en-
eration occurred in the hrachiiini conjunctivum, hut oidy
secondary atrophy (diminution in calibre of tlu' individual
fibres). It is of <^reat iin]>ortaiice to note that in this case von
Monakow explicitly tells us that the corpus dentatum was not
injureil. lli' further belii'ves that the tibres of the brachium
conjunctivum which exteiul beyoiul the red nucleus probably
arise in tlu^ opposite cerebellar hemisphere, and end free in
the gray matter
)f the tei,nnentum. Von Moiuikow is of
the opinion, therefore, that the brachium conjunctivum con-
tains both centrifugal aiul centriitetal libres, and that it is
preferably the latter which uiulergo atrophy of the secoiul
order after defects in the pallium, so that any direct connec-
tion of the brachium conjuiu'tivum with the cortex can be
safely denied.
Thomas t followed by Marclii's method degenerated fibres
not only to the nucleus rulier, but also beyond it to the ventral
part of the thalamus. No tibres could, however, be traced
l)eyoiul the thalamus to the nucleus leutiformis or to the pal-
lium. MirtoJ makes the libres of the brachium conjuiu'tivum
end chieily in the contra-lateral nucleus ruber, but partly also
in the ventro-hiteral region of the thalamus. According to
Flechsig, some of the fibres go to the nucleus leutiformis by
way of the dorsal white matter of the nucleus hypothalamicus
(corpus Luysii), otherwise km)wn as FcJif., of A. Forel. He is
of the opinion further that a certain number of the fibres pass
out to the cerebral cortex, terminating there in the region of
the gyri cejitrales. The upper portion of the soniiesthetic path
to the cerebrum by way of the cerebellum will l)e described
more fully in Chapter L.
A study of the stages of myelinization of the brachium con-
junctivum makes it seem extremely prol)al)le that fibres of
different systems are contained in this bundle. Thus, von
* voii ]\Ionakow, C. Ai'chiv. f. Psycliiat. u. Nerveiikr., Herl., I?(l. xxvii
(1890).
t Op. rii.
X Jlirto. SiiUc (Icffoiicrnzioiii siMMiudiiri ('erel)cllo-ci'rol)nili. Arch, per
le sc. mod., Torino, vol. xx (IH'JG), p. lU.
II -v,"
: -'i
iH
(558
TIIK NKUVOUS SYSTEM.
IU'cIiUm'cw * (listiiif^iiislicd ciisily four (iistiiHit l)un(Il(^rt wliicli,
in tlic niitldU^ of the pons, as hooii in rronn section, present u
typieiil to|)o;jfriiplii('al Jirriinffernent (Ki}jf. 4:51 ). Of these, the
first to l)econie niedullated (t'ditus 2H cm. lonjj;) is tliat which in
Fio. lUl. — Sclu'iiiiilif cross scctiitn tliruiiKli tin' pars dorsiilis poiitis at its.jiiiictiitn
willi Die istliiiius rlioinbciiccpliiili. i Al'li r \V. viiii |{('clit<'rcw, Die LcituiiKs-
lialiiicii iiii (ifliini iiiiil liiirkcmiiark, Driitsrli von Iv. NVciiilMTf;, II. Aiill.,
Lci|>/.. I lsi)!»i, S. 'SMi, \'\'^. DIM. ) (((/, aciucdiictiis cfrcliri ; lip, I'lisciciiliis limni-
tiiiliiialis iiicdialis; /(■, t'asciciiliis ccntriilis tcKiiiciiti icciilralr lldiihriihnliii) ;
fi/ii, (iliii's IVdiii the region (if the colliciilns iiifcricir to the iiuclciis reticularis
(cjimcnti ; I\'. N. Iniclilcai-is : liii,, tilircs of tlic Icimiiscus iiu'dialis from the
coiitra-latcral iiiiclciis fiiiiiciili ctiiicati ; hiin. lilircsof tlic Icinniscus iiicdialis
from the contra-lateral iiiiclciis fiiiiiciili fjiiK'ili^: '"'/'. vim Mcclitcrew's
medial accessory Icmiiiseiis ; hiisti. von Hcclilerew's scattered lilindlcs of the
lemnisciis ; hiil. leiiinisciis lateralis; iics. nucleus ccntiiilis superior, jiars
Iiicdialis; ticsl, nucleus cent nilis superior, iiars lateralis ; «/, iiiieleus Icmiiisci
lateiiilis ; iirl, nucleus reticularis tcjiiiienti poiitis; yic, dorsil, pi;,, midillc,
pcuK iiieclial. pi;^ ventral liiindle of the lirachiiiin colijiinctivuiii ; /iCu repre-
sents the <oiiimissure lietween the iinclei siipcriores nervorum vestilillloriiin ;
sfr. siilistiintia ferrugineii , I', nidi.x lie.sccnilens (inescnceplialica) iicrvi
tri;;eiiiiiii.
a seotioJi tliroufjfh ii plane corres})ondin}i; to the middle of the
pons lies in the most vejitral part of the hra(diium eonjnnc-
tivum ( Fij;. 4;{l,/^r„, and Fiif. V.Vi, 4(i). This linndle has nothing
to do with the coreiiellum, l)ut is tiie hnndle above mentioned
wliich fin'ms ii commissure between the nuclei nervorum ves-
tibulorum supcriores of the two sides. Of the three other
* von RiH'literpw, W. Dio Leitiuigsbahnen iin Gehirn und llllekeimiurk,
Lcipz. (18!)4), S. i;J5.
^iil
Itu
OUOUI>IN() AND CIIAININO T()(JHTIIKH OF NKUUONKS. (159
bundles, tlio most dorsal ono ( Kij,'s. I'M, pc,, iind 4;{!i, 45) is me-
dulliited ill fd'tusos about 'A'.i cm. loii<,'. Tliis bundlo appears to
])(• ('((iiiu'cted with tlu! tnudcus fasti<,ni and with th(! (lortcx of
the vermis (von Hi'chtcrow). Its lilucs pass to the decussation,
{;ross to the opposite side, and arc interrupted in the red nu-
(deus, since no fibres are niedullated beyond at this sta^o.
The third bundle (Kifj. 4:{1, //r„), medullatcd in tVetuses :{5 to
I5S cm. loiif,'), lies between the dorsal and ventral bundles (Fiff.
4;{'^, W). In the cerebellum it is rdatc^d especially to the nucleus
f,dob()sus and the nucdeus emboliforrnis. Some of its fibres ap-
pear to be related directly with the cortex of the v(irmis supe-
rior. The fibres of this bundle decussate with the; other fil)res
of th(( bra(diium conjunctivum, becoujc partly miiiffhid with the
fil)res of the dorsal bundle, and comc' in relation anteriorly to
the cells of the red nucleus.
The fourth bundle (Fig. 431, /;r,„) (l)ej,'inninj( to medullate
in the new-born bal)e) consists rnaiidy of very fine fibn^s whi<di
lie partly in among the fibres of tlu; other bundhis, i)artly me-
dialward from them. In the cerebellum the fibres of this bun-
dle appear to stand in relation to the cortex of the cerebellar
hemispheres, and in part to the nucleus dentatus. The fibres
of the bundle decussat*^ with the other fibres of the brachium
conjunctivum, and in front are related to the red nucleus.
We fortunately possess a certain amount of positive informa-
tion concerning the origin from cells, of the axones of the
fibn^s of the brachinm conjunctivum. This has been gained by
the application of (iolgi's method, especially by Ramon y Cajal *
and Martin. f
Kamon y Cajal finds that certain of the fibres of the brachium
conjunctivum in the mouse arise from the nucleus dentatus.
He emphasizes the fact that ])y no means all the ascending
fibres come from the nucleus dentatus, some having another
origin, perhaps the cerebellar cortex. This view has been sup-
ported by studies made with Marchi's method, and Ramon y
Cajal has shown that axones of Purkinjc; cells go directly into
the superior cerebellar peduncle. All the thick fibres, however,
* Hdtnuii y C'ajal, S. licitrag zuin Studiimi dor ^lediilla Oblongata, etc.,
1j(M))z. (1H!)(5), S. 17; also Ganglions eon'bcllcux. Hibliogr. anat., Par., t. iii
(iHyr)), pp. ;};5-42.
•f Martin. I'. In Franck's Ilandhucli der Anatouiie dor Ilausticre, Drilte
Aullagi', 15d. ii, Stuttgart (lHi)4), S. 37«.
i
V ^,
tw;o
m
.
TIIK XERVOrS SYSTEM.
A
fS
mi
I
(JKorPIXC} AM) CIIAININMi TodiyniKir of NKIIIONKS. cni
which f,'() into tlio hrachium cojijiiiu'tivuin arise, lie states,
from the micU'us (h'Utatiis of the same sich'.*
The colls of the nucleus dcntatus arc lar<fe, triaii^Milar, or
stellate, and exhibit uneven di'ndrites. 'Die tiiick axones arise
either from the cell body or from one of the dendrites, give off
one or two collaterals inside the nucleus dentatus, and pass over
into the brachium coiijiinctivuiii of the same side (Fig. 4:5:}).
In some cases it has been possiljlc to folhtw the axone even
outside the cerebellum, not only in longitudinal sections, but
also in transverse sections.
nucleus funiculi jinuilis ; ,',', fibres from the resioii of llie colliculiis inferinr
to the nucleus reticularis tcKUienti anil to the pons. I'lnlrl — ,;.:, lihres of
fasciciihis centralis teunienli {iriilinlr lliiiilinihnliii ) ; ,',(, litres passinj; hy
tlie rai)lie from tlii' nuclei pontis to the foiinatio reticularis fjrisea ; .:.■<, lilm's
of the spinal liundle ( Voii itecliterew l ol'tlie hrachiiini pontis; .(.), .;:/, ,{..'. dif-
ferent hundles in the hracliiuin conjuiK'tivniii. Illm — ;, fasciculi ionni-
tndinales ( pyrainidales 1 ; ji:, lilires of medial accessory liundle in lemniscus
medialis (to motor iiiulei of cerehral nerves) ; .(';, tihres of cereliral hnudleof
hrachium pontis; ,'iii, frontal cerehrocorticopontal path ; ■;/, temporo-occipital
cerehroeorticopoutal path, (iri'i'ii — .'/, fa>ciculus lon>,'itudiualis medialis; .v.
lihres \vhi(di represeut the poutal continuation cit' the I'aMiculus lateralis pro-
jirius of the spinal i-ord : ;'/, commissural hundle lyinji ventralward from the
lu~,)chiuiu con.junctivum.
li, transverse section throunh the hrain stem; level of iiednnculi cere-
bri. TIk' rifht half illustl-.Ues the level of the colliculiis inferior, the
left half that of the cidliculus supi'ricu'. (After \V. von Mechlerew. Isjit,
somewhat modified.) .Ii/.c, a(|ueduclus cerehri ; ''.((.»/., cnrpus Kcnicula-
tum mediale ; Cni., corpus mammilhire ; C.s., colliculiis superior ; .V./l",
radix N. trochlearis ; Sii.r.i.. nucleus colliciili inferioris; Sii.f.l.in., nii-
chns fasciculi loiiKitndinalis medialis or nucleus commissnne posterioris
(iihiTiT Oi-iihimiiiiiriiiskfrn of Darksclie witsch ' ; Mn.l.l., von jtecliterew's Ciir-
jDi.i iiiiriihiiii'iiiiiiiiiii : yiij."., niK'lelis lateralis superior of Fltchsi^ ' iiiiflriin
iiiiiiiiiiiiKiliis of voii l!echtei'e\v ) ; Xii.ii.III. nncleiis nervi ociiloniotorii ;
Nit.r., niich'Us riiher ; >'.».. snlistantia uiKia ; >7. ;(;•.(•.. stratum ^iriseiim
centrale. Itid I'-', lihres of lemniscus lateralis which enter colliiiilus in-
ferior; J'J. tihres of hrachiuni <|UadriKemiuum iiiferins from the colliculiis
inferior of the same and of the oiijiosite side ; /.;. tihres of the lemni.scns
medialis ori}.'iuatiuj; in the nucleus funiculi ciineati ; /.;', tihres of the lem-
niscus medialis f-'oiii;; to the corjiora (iiiadrijjeiiiina ; l(i' . scattered hiiiidles of
the lemniscus which t;o over into the hasis pediiiiciili ; IT, renion of the .scat-
t<'red lihn's I late to developMif tlu' formatio reticularis. ]'elliiir — /'^ tihres
of lemniscus medialis from the iiiicleiis funiculi }.'iacilis; .^S. tihres from the
nucleus colli<'uli inferioris to the thalamus laccordiii}; to voii IJechtercwi;
rill, fibres from tire colliculiis superior to the cerebral cortex. \'iiili-l — .;;/, ,(..',
.{.I. fibres of the brachium conjuncti viim belore their entrance into the red
nucleus; .}?, .),v. fibres from the red iiiicleiis to the nucleus lentiformis, the
t ha la 111 IIS, ami the cerehral cortex i these a re the radiations of the red nucleus i ;
.l-'i, fibres of the fasciculus eeiitnilis tejjmenti ■ I'fiitrnlc lldiihiiihiiliii '. (li-rcii —
.'', fasciculus louj,'itudiiialis medialis: .,7. fibres of the dorsal jiart of the coiii-
niissiira i)osterior ; .<'/'. fibres of the veinral ]mrt of the commissiira posterior ;
S7, fasciculus retrotlexiis Meyiierii : ..'.'. fasciculus thalamomammillaris i \'i((i
d'.Vzyrii; ..'.)'. fasciculus peduiiculomammillaris pars basilaris ( peduiiciiliis
corjioris mamniillaris i ; ."i.^', fibres from the substantia fjrisea of the colliciiliis
sili)erior to the ri'niou of the nucleus ruber of the opposite side. Itliii — .J,
fasciculi lonfritudiiiales < pyrainidales i ; .■;(*, fibres of frontal cerebiocorti-
co])ontal i)atli (medial bundle in basis pe<lunculi ' ; 'il, fibres of occijiito-
temporal cerebrocorticoiioinal path lateral bundle in basis pediiuciili i ; A',
fibres of the accessory bundle of the lemiii.s<us ; .■''/, fibres coiiiiectinji the
substantia nigi-.i with the cerehi-iil hemispheres.
7:t|
\
Op. cit,, S. 20.
MV2
THK NKI{V(H'S SYSTKM.
A vcrv iin|i(irtiiiit obscM'Viitioii, wlii(!h we owo to Ramon y
Cajiil, Ims hccii iiiii(k' in HUfjittal and latoral wections. At tlio
point where the flljres of tho brachiuin conjunetivum ieuvo the
Kl(i. 4^3. Fniiitil section tlirc)iii;Ii tlic I'crcliclluiii and pons of a Hi'tal mouse.
(After S. Uanioii y Ci.jal, Ui'itra^c ziini Stinliimi <ler Medulla ( Hiloujiala. etc.,
IJresler, Leiit/... lsit(i, S. lit, l^'i^. .'). > .1, sensory root oC N. trif;eniiuus ; />',
motor root of N. trigeminus; (', nnilens motorius prineeps N. tri;;eniini ; I),
aseeiidiiiK limlis of liifurcation of sensory axones of N. Irij;einii"is ; /■.'. de-
seeiuliu;; tmndle from liraeliinm eonjiinetivum ; /•', liraeliium eonJEinctivum ;
a. imeleus dentalils; a. liifurealinj; sensory axones of N. trigeminus; h,
t<*riuiuals of aseeudiu}; limlis of hifureatiou ; (•.(•(•lis in amoiif; tihres of de-
secndiuK l>nudle from liraeliinm eonjunetivuui ; c, cell liodies of lower motor
neurones in the nucleus motorius prineeps N. triKemini ; it, axones of the
latend sensory central Irijieminal and ghissopliaryuKeal path wliieh give olT
collaterals to this nucleus.
fef'i
i
(■IfOl'l'lN'd ANIt CII.MNINO T(>(iKTIIHR (»!•' NI'U'KONKS. JUJ.'i
cerebolliun and ^o over into tlic dorsal uiid lateral 8urfa(re of
tlu? pons, tnuiiy of tlic fibres f^ive olT at rij^lit anj^lcs a stout
(iollatcral, wliicli passes in a (lescendin^' dire(ttion. At tinieH
the division resenililes more a bil'iireation of the axone (I'i^.
4.'{4). Tiiis i)undle of (M)llaterals arising,' from tiio Hhres of
the braohiuin eojijunctivum leaves the braehitim and des(!onds,
forniiiif^ a fasciculus (U'rebellaris lateralis descendens (Ramon y
Cajal's litlci'dlcs (ihsh'iijnulrs KlfiiiliirnliUiKlrl).
Fig. 434.— I^itfi-iil siiKittal scctidii tliroii^li the pons and (•crclxUiiin of a fci'tal
niotisr, showitit; I he si nsory ixirticin nf tlic N. (rififniiniis. ( After S. Kiinion y
Ca.jiil. Hcitni}; zuiii Sliulimii dir Medulla (Hiloii^'ata, etc., Leip/... isiHi. S. t,
Fifj. 1.) .1, iKirtiii niajcir or .seiisoi-y root ot' N. tri^'eiiiiiius ; the iiidividiiiil
axones dividing inln an aseeiidint; ((/ ) aixl a deseendiuK limit [h) : c, lerniiiial
branelies (if ascending lindi; it, mot lilires wliiili sink into tin' depth ; c, dor-
sal part of descend itiK portion of sensory root ; li. hifiircation of axones of N.
vcstiln'li, the ascending lindisl;;) ^oinj; to the eereliellnni, the deseendiliK
lindis (f) Koinn downward to the medulla olilon^ata ; (\ hiiiehinm con-
jlinetivnni ; />, fa.seiculus (M'reliellaris descendens; /.'.corpus restiforme; /''.
lemniscus lateralis ; //, coriais trapezoideum ; (), nucleus deulalus.
ll
L
This descending cerebellar bundle consists of several small
bundles arranged more or less in the form of a plexus, and sep-
arated from one another by cells, lie has been able to follow
these small bundles in latenil ssigittiil sections along the
tractus spinalis nervi trigemini, in reltition to which it is medi-
! i
fit 14
Till-; NKUVOUS SVSTKM.
ally pliK'(M|. Ill its (M)iirH(' (•((llntcriilH iirc j,'ivcn olT to adjiicciit
rc^'ioiis (»r tlio foniiiitio rcticiiliiris. In Inmsvcrsn HCtctioin tluf
dosceiKJin^ (•crcliclliir bimdlf ol' Ciijiil in hccii to run at tirst for-
wiinl and vciitralward, (intsidci the priiicipal motor nucleus of
tilt' tri;;('tninus, medial from tlu* upper part of the sultstantia
^elatinosa. Soon aftt'r it lias passed medial to the latter it
turns to run lon^iitudinally, and forms a larj,'e hundio of lon^'i-
tudinal lihres in tlii^ forimitio n^tieularis f^risea just medial to
the substantia {felatinosa of the traetus spinalis nervi ti'i^femini.
In its transverse course, while it passes lateral from the princi-
jial motor inudeus of the trij^eminus, it gives oil' some collaterals
\vhi(di hrantdi in iimouf,' tho colls of this nucleus, aiul, further
on, following the longitudinal course of the medulla, it givea
olT collaterals to the mudeus nervi facialis, the ccdls in the for-
nuitio reticularis grisea, and perhaps also to the nu(deus iim-
higuus and to the nucleus nervi abducentis. Kanion y Cajal
was unable to follow tho course of this bundle lielow the
olive, as his set of serial sections unfortuiuitely stopped at
this point, although the })ath was distiiu-tly impregnated
and evidently went farther. lie concludes that this bundle
has nothing to do Avith tlu^ descending cerebellar path de-
scribed by Mar(dn. He Indieves that at least a part of its
fibres liave been descril)e(l by von Bechterew as the cei'cbellar
root of the trigeminus, ])y Kdingor as the direct sensory cere-
bellar path of the trigeminus, and by Cramer as a central sen-
sory path of tho trigeminus.
Martin has observed, by (Jolgi's method, axones ])assing
from cells in the red nucleus througli the decussation to tho
hratdiium conjnnctivum of the o])posite side. These axones
give off collaterals before and after decuissation to the fornuitio
reticularis. These possibly etn'respond to the fibres of Edingor's
traetus tegmento-cerebellaris ajid to the cerebellopetal degcTier-
ation observed by Mendel * and by von Bechterew. f For the
structure of the nucleus dontatus in the new-born babe and in
* Mcndol, V. (cited by v. Hochtcivw). NVurol. C'l'titrall.!.. I>cipz. (IBsr)).
•f V. Bi'ditercw, W. I'eljer sypliilitisclie disstMiiinirtc, (■('iTt)i'(i-s|>ii)nlc
sklerose nebst lipincrkungen ucber die sociindtire Dej^ciipration dcr fascrri
des VdrdrreiilvloiiddriischcDkt'ls dcs fciitralcn IlMidH'!d)iindt'ls uiid dtT
Seldeifensehieht. Arch. f. Psyelnal., etc., IJerl., 15d. xxviii (IHiiG), S. 742-
772. ' ■
:l
(lUoriMNCJ AND CIIAININd TodKTIIKIf <)l' NKrUOM-lS. r»»ir»
udult hiimmi hciiigM, tlic render is rerfrn-d to tlio roHuurcli uf
liiij^iiro.*
It is olivious tliat while hy fur the majority are eerehelio-
lmI, ill tlie hriiehiiiin (■oiijiiiietiviiiu there are axoncH |iassiii<r
fill
ill both tlireetioiis. 'i'lie t<i|Mi<^M'a()iii('iil tlist rihiit ion of these
uxoiies retiiuins yet to i»e workeil out. it is very iiiiporluiit
that tiiiri hv (leteriiiined for euch of tht; four IxiiidleH which ciiii
so easily l)e isolated Ity the study of riiyeliiiizatioii.
ill passiii;^' it should lie iiiciit ioiied that a Kussian invest i;ra-
tor, Kliiiioil',f has demonstrated, l>y Marehi's method, lihres
(•oiiiieetin<; tli(^ eerehellum of one side hy way of the hraehiuiii
eonjunetivum with the contra-lateral iinclens nervi oculo-
inolorii.
'I'here are eer( l)ellofu;,'al paths also in the hrachiiiin poiitis
(middle (rerehellar peduiule) hut the (fvideiice thus far is
uf^ainst the view that these aic cerelinipetal in nature. (Cf.
Chapters liMII and L.\I\'.)
* Lupiro. K. Sulla slnillmii del imcle" deiitalo del ei'rvelltilo iii'll'
uiiiiii). Miiiiilun'. /.uol. ilal., l''ircii/,(!, vol. vi (IHIir)), pp. .l-l^.
f KliiiicilT, I. A. On Ui(! ('niiiii'ctidii dT tiii- CiTflu'lliim willi tlic Nucleus
<jf llic N. ociiloiiiotoriiis. N'racli, .St. lVici-.lj., vol. xvii (1N!J(J;, p. |(il:i.
I
44
-mmi^i,
i
4. Central Sensory Axones passing into or through the Cerebral Peduncle, and
the Terminations of such Axones.
CHAPTER XLVll.
ON THK STRrCTrRE OV THE HYPOTHALAMIC RKCUON AXD THE
COURSE OF THE LEMNISCUS MEDIALIS.
Centripetal fibres which forward bodily iiiipulses through the cerebral
peduncle toward the sonuesthctic area of the cortex — Forel's studies
(1887) — Ffilil //^— The zona incerta — Tiui nucleus hypothalainicus or
liUys' body — The nuclei of the thalanuis — von Kiilliker's studies-
Researches of Nissl — Investigations of von Monakow — Tscherinak's
studies.
The lemniscus or fillet— .Subdivisions — Leuiniscus niediaiis — licniniscus
superior — Various neurone systems in the lemniscus. The '• cortical
lemnisiuis," direct and indirect — View of Flechsig and lloesel — View
of von Monakow and Maiiaim — Other studies of lemniscus — Demon-
stration of direct cortical lemniscus in cats by IMarchi's method
(Tschernnik).
All the ci'iitripetal paths curryinsj; impulses toward the cere-
briiin iinist pass throiij^h tlie cenihral })e(liiii('le. We liave seen
that the bundles of fibres coneerned in carryiuff impulses from
the bodily sense organs (iis opposed to those of s})e(^iul sense)
may include the followiiifj; : (I) The lemniscus medialis; (2) the
fascieidus lon<j;itu(linalis medialis; (:5) certain longitudinal
bundles of the formatio reticularis ; and (4) the brachium con-
junctivum and some of the axones arriving from the nucleus
ruber which pass cerebrtdwiird. These various fibres (axones
of central neurones) pass through the pedunculus cerebri
(mainly or entirely through the tegmentum, not through the
pes, or basis) to reach the diencephalon, where most of them in
all probability terminate in the hypothalamus, in tlie thalamen-
cephalon, or in the nucleus lentiformis ; a few of the ax(mes
may pass through the diencephalon, without terminating in it,
()G0
GROUIMNCJ AND CHAIN'INC. T()(JETlIKli OF NEURONES. r,(;7
so as to rcadi tlie cerebral cortex directly by way of tbe
internal capsule and the corona radiata {dircrte ItindenHrhli'ife
iind a part of the Ildiihcnsfrdlilnng of the (iermans). The
fibres wliicii torniinate in the hypothalamus (mainly in the
niu'leus hypothalamicus) and in the thalamus (mainly in its
ventro-lateral portion) apparently do so in conduction rehition
with the cell bodies and dendrites of neurones of the tliird (aiul
often doubtless of a higher) order, the axones of which run out
through tlie retro-lenticular portion of tlio occipital limb of the
internal capsule and through the corona radiata to reach the
cerebral cortex. The region of the cortex in which the axones
of the general sensory conduction path here considered termi-
nate, I have designated as the sonu«stlietic area of the cortex.*
It includes, in all probability, the central gyri, the posterior
portions of the three frontal gyri, the lobulus paraccntralis and
perhaps in part the gyrus cinguli (Flechsig)and portions of the
parietal lobe Ix'hind the posterior central gyrus (von Monakow).
In addition, doubtless, fibres of this sensory path terminate in
the corpus striatum.
The study of the upward continuations of the sensory con-
duction paths of the tegmentum is fraught with extreme diffi-
culties, especially in man, in whom the brachium conjunctivum
and red nucleus are colossally developed in comparison with
tlu' other tegmental structui'es. It has been attempted by
purely anatomical methods ; by the method of secondary degen-
erations, and by the embryological nu>thod. Thus far Init little
help lias been gained in this connection by the use of Colgi's
mi'thod, but a lieginning has been miide. The application of
tlie method of Nissl, though full of promise, has as yet been
limited.
The purely anatomical studies, extending the earlier re-
searches of Reil, Bur(hich.+ Arnold, (Iratiolet, | and Luys,* have
been carried out chiefly with the aid of serial sections by Mey-
::;":'l
II
* T wish 1o tlnink Prof. Gilderslocve. of llic.lolins Hopkins University, for
siij^fjcstinfj lliis term as a suitable Eiifriisli e(|uivalent for Munk's h'iU-fier-
fi'ihl.iphan'.
\ Hiirdach, K. P. Vein Bane iind Tjoben dcs (Jeliirns. Tjoipzifj, 1(^19-'2(i.
X fifiuret et (Jratiolet. Anatomie comparee du syslenic ncrvcux. I'aris,
lH;S9-r»7.
* IjUVS. J. Reclierclies siir k> systenie nervcux t^erebrospiiial. I'aris,
1H65 ; Iconof^raphie photograpliique dcs centres nerveiix. Paris, 1873.
068
TIIK NERVOUS SYSTEM.
iiort, * Forol, t (^ianser, J Dojerine, * von KoUiker, || Mills, -^
iiml von Monukow.^
Forel, in his oxhaustive description of the tegmental region,
attenn)ts to follow from the pons and midbrain the main longi-
tudinal paths upward into the tegmentum and hypothalamic
region. His conclusions regarding the various bundles which we
have seen may be concerned in the (sarrying of impulses from
the bodily sense organs — namely, the fasciculus longitudimdis
medialis, certain longitudinal bundles of the fornuitio reticularis,
the nu'dial lemniscus aiul the brachium conjuiu'tivum, and the
hbres coming out of the red nucleus may here be referred to.
As regards the fibres of the fasciculus longitudinalis medi-
alis, Forel I found that the majority of the coarse fibres and
some of the fine fibres reaching the level of the posterior com-
nnssure of the brain enter into it. The majority of the fiiu'r
fibres, however, went farther, passing through the fasciculus
retroflexus Meyuerti to become lost in the gray matter of the
tegmentum, mingling with fibres from the formatio reticularis,
and perhajis reaching the area in the hypothalamic region
designated by Forel as Ft'ld IL [ride infra).
The longitudinal bundles of the fornuitio reticularis are
much confused in the midbrain by the decussatio brachii con-
* Meyncrt, Th. Vdiii Gehiriio der Siiiifrt'tliiere. Article in Strieker's
riandbiR'h der Lphre von den (iewebon, etc., lieipz. (1871-'T!J) ; also I'sychiu-
try, translated into Enj^flish by B. Saclis. New York, 1885.
t Eorel, A. l?eitriii;e zur Kenntniss des Thaianius opticus nnd der ihn
unigel)enden Gebilde l)ei den Silnjjethieren. Silzungsl). d. k. Akad. d.
Wissen-sch., Bd. Ixvi, VVien (1872). S. 25-58.— UntersuclninKcn ueber die
llaubenregion nnd ilire ol)eren Verknnpfniigcn iin (ieliirne des Menschen
nnd einigcr Siiufiethiere, niit Ueitrilsen zii den Meliioden der Ueliirnnnter-
snclmn;^. Arch. f. Psyehiat. ii. Nervenkr., Berlin, Bd. vii (1877), S. ^93.
X fianser, S. Verfjleichend-anatoniisehe Studien ueber das Guhirii des
Manlwurfs. Morphol. Jahrb., Leipz., Bd. vii (1882), S. 501-725
* Dejerine, .1. Anatoniie des centres nervenx. Paris, 1805.
II von Kolliker. A. Op. n't.. S. 42H.
^ Mills, ('. K. Sections of the Cerebral (lunglia. wilh Heinarks on their
Anatomy and Ticsions. Tr. Path. Soc. Phila. (1H7»-'81), vol. x (1882), i)p.
170-182.'
^ von Monakow, (". Experiinentelle u. patholoffisch-anatomisehe I'nter-
suchniifjen ueber die Ilaubenrefrion, den Sehhiifjcd utid dii' I^ejjio siibtliala-
niica, nebst Heil riijj;en /ur Kenntniss friih erworbener (iross- und Kleiiihirn-
defeete. Arch. f. F'sychiat. u. Nervenkr., Merl., 15d. xxvii (1805), S. 1, ;58(J.
I Op. cil., S. 417.
(iUOUPlNG AND CHAINING TOGKTIIKR OF NFATROXKS. «w;9
«;7o
TIIH XHUVOUS SYSTEM.
I t
'!:;•*
„ fi
jiinctivi. They become displiicod dorsally iiiid latorally, uiid
jibove the red nucleus pass apparently into the diffusely limited
oval Frid If. A special mass of fihri's of the forniatio i-etic-
idaris, desiffiiated as /[(fu/u't/ft/sri/rr/ii or fasciculi to^menti by
Meyncrt, and especially well seen in the dog (Fig. 4:55), pass up-
ward and apparently go directly to the most ventral i)arts of the
tlialamus.
The fibres from the brachium conjunctivum and from the
red Jiudeus were especially studied by Forel. He descril)(>s
})articularly the white matter of the dorsal surface of the red
nucleus and that of the lateral surface of the red nucleus. He
Tcenid seinicircHlartn. -»>.
A'ii(7ci(s liitfriilis fhaldini.
-j^i illr
Ventriciilus tertius.--'\ ;.// , /MJfl
Lamina ini'ilullaris iiteUialis. '^^,
Nucleui medialis thalami.
na mrilullaiin lutentliD
Nucleus ruber. >.. " ,ji?'i!tJt Cs'
A', oculomotorius.l
^Xucleus h !ij)oth)ila m ir>is
tcorpun Liiy.ii).
BATh of Forel.
Substantia nigra.
Fi(J. 43ti. — Froiitiil sci'tidii through tlio liiiniaii brain stem, i After. \. Forel,
Areli. f. F's.veliiiit., Herl., Hd. yii, 1H77, Taf. vii, Fif?. 10. i ll.iTIi, lar^e
l)Uii(lle of (il)res wliicli, coining from the iiuclcii.s rillier and its caiisule, runs
upward, lat<'ralward, and dor.salwanl to the ventral part ol' the tlialamus to
tile reticular layer, to the lamina medullaris lateralis, etc., where the lilires
become so interwoven with others that the.v can not he followed farther;
Furers Fold II, dorsal white matter of re^io suhthalamica.
believes that the dorsal white nuttter consists of fibres from
the bratdiium conjunctivum, from the fasciculus longitudinalis
medialis, and from the forniatio reticularis inextriciibly mixed.*
On the lateral surftice of the red nucleus he describ(>s a mass of
fibres wliicii passes oblitjuely latendward and dorstdward toward
the cerebrum, converging to form a bundle which he calls BATh
(Fig. 4:5()), and which he thinks, in the nniin, enters into the
ventrtil part of the thidtimus, there again to break up into sec-
ondary bundles which ;i])])ear to help to form not otdy the
liimiua medullaris latenilis, but also other himintc medullares
and radial bundles of the tbahimus.t Lateralward this bundle
* Tf one studios seriiil sei'tioiis throuji^li the brain of tlie new-born biibe,
all of these bundles ean be di.slinLlly recognized,
t Op. fit., S. 425.
» i
(ilioriMNd AND ClIAIXIXO TOOETIIHTI OF NKURONKS. <;T1
touches tlio zoiiii incortii, while (U>rsiihvar<l, somewhat uhove the
red uucknis, it fuses witii Frid II.
Forel ei Fi'hl II wouhl therefore bo miide up miiiiily of fibres
from the capside of the red mick'us, partly of fibres passiii<;r
tlirouf^li tlie red nucleus from below, partly from fibres which
represent meduUated axones from the cells of the red nucleus
itself. There are contained in this Feld II, then, according to
Forel, fibres from the brachium conjunctivum, from the forniii-
tio reticularis, from the fasciculus longitudinalis nuMlialis, and
from the red mudeus.
As regards the main portion of the lemiuscus, Forel de-
scribes it as bending dorsalward and lateralward at a level cor-
responding to the lower end of the red nucleus. It passes
close to and parallel with tiie bundle which he calls BATh
and runs in a direction toward the pulviiuir, interweaving
with the IlanhcnfaKrikdn^ and becomes lost in the gray
matter of the tegmentum, so that its fibres can not be further
followed.
Very convenient for purposes of description will be found
the division of the hypothalamus (regio subthalamica)* adopted
by Forel. He retiognizes three layers: (1) A dorsal layer of
white matter; {'i) a middle layer, the so-called zona incerta,
which laterally is continuous with the reticular zone of the
thalamus ; and (o) a ventral layer, somewhat more laterally
placed, the so-called Luys' body, now known as the nucleus
hypothalamicus (corpus Luysi) (Fig. 4:57).
The dorsal layer of white matter just cerebralward from the
red nuckuis consists of an area of very fine meduUated fibres
which Forel designates as Fchl II. This field nuiy receive fibres,
Forel 'links, from {a) the fasciculus longitudinalis medialis;
* 'I'lic limits of the liypolliiilfuniis (rofjio suI)Uialami('u), or Wcriiicko's
St nit inn intcriiu'diuni, as defined by Forel, are as follows: Dorsally it is
covered l)y the tiialainns. l)eiiij,' se])anited J'roni it l)y the lamina medullaris
lateralis; medially it is limited l)y the stratum s'"'^''"'" ceiitrale of the
third ventricle and by t he fasciculus thalamoniammillaris (Vieq d'Azyri) and
the anterior root of the fornix; ventrally by the lamina perforata posterior
or by the corpus iiiammillare. as well as by the substantia nifj:ra with the basis
peduiiculi: laterally by the internal eapsuli' iiud by the relicidar zone (^'*7-
tcrKr/iiclil) of the thalamus. Melow it is limited iiy the nucleus ruber and
the fascieuhis retroflexus (Meynerti); above it is continuous with the sub-
stantia iiiiiominata of Iteii.
mn
ii
(M'J
THK NKI{ vol's SYSTKM.
(//) loii^itudiiiiil hiindU's of the I'oriiiatio rcticiiliiris ; iind (r)
possibly jiIho lilircs from llic Itnicliiiiin (■oiiiiiiictiviiiii iiiid tlx'
rcti iiU(d(>U8, inasiiiiicli us he Itclicvcs it iiiiiy Ix^ lool<(>d iipori us
a (MHilimiut ion cfrcbridward of a process of Mic capsule of white
tuatler siirroiiiKliii/^^ the red iiiicleiis. It is eoidiiiiioiis laterally
i''l<i. 'i;<7. I''riiiit:il si'clidii t liruii^li llir liiiiiiiui lirniii sicni slmwlii^ siiliiliv isiciiis
of li.v|M(lli:il;iiiiic n'Kiiiii. (Al'lci- A. I'unl. Arch. I'. I'svcliiMl.. Itrrl,, Itil. vii,
IS77, 'l";ir. vii. I'l^. II.) i/. ililiculc iinniiiisMMC .jii.st ventral In llic vciiliic-
\\\\i> tt rliu.s.
with tlu^ lamina iiiednllaris lateralis. Ili<,diei' up, in sections
passinjj^ throuj^li the posterior part of the corpus iiianuiiillare,*
Korel descrilu's the /''cA/ // as splittinj^ into two portions, one
dorsal { Fr/i/ //,), remaining' in directcontiniiity with the hiinina
niediilhiris lateralis of the thalamus; the other ventral { /''r/if
//o), sinks into the zona incerta, heectmes more compact, and
st'uds ii process (of white mutter) latoralward which passes as a
Hat lamellii over the cerehral extremity of the dorsal whito
capsule of liiiys' hody. 'i'his lateral w ite process from tin*
/'}•/</ //« j^rows thicker farther up, is closely attached to iiUys*
hody, and bends around its hitenil mar<fin into the inlermd (iap-
sule at its junction with the bjisis ])edun(!uli. in doin^ so, it
is joined by lateral-ventral bundles from Luys' body, and, liko
these, divides the capsula interna into rcctanj^ular fields (Kijjj.
4;KS).
The zona incerta, a mixture of ji;ray nnitter and wliite matter,
lies between the dorsal layer of white natter and Luys' body.
* Forol's sections are <'ut at rif^lit aii^jlcs lo an axis fjoiii;,' from tlic fron-
tal [loli' to tlie occipital [lole of tile (.•uri'linmi, not al ri{;lit uii);lus to thi' a.xis
of Meviiort.
"lif
i« U
(i|{(H'l'IN(J ANK CIIAININd TOCi KTII Kl{ <»!•' NKl'KoNKS. (;7;{
Forcl could s!iy luttliinfi <l('liiiilc refill re I iii;^' {\w luiturc or rdii-
tioiis of the filtn^H iiiid (-(^IIh sitimtcd in it.
Tlio iiiKilcMiK liypolhalariiiciiH (rorpiiH IjiiyHi), the iiioHt ven-
tral of Forel's three layers, is a. hieoiivex, traiisverseiy oval,
leiis-sliaped mass, somewhat sinaller than the red nucleus and
very dilTcrent in shape. It can hc^sein to liej^in in sections cor-
respondinjr to the plane ol" the i'aseiculus n'trolh^xiis .M(!ynerti,
in which it lies dorsal to the hasis pediineuli and th(( untorior
pari of the suhstaiitia ni<rri
M
ore anteriorly it iiu-reases
rapidly in si/e, assumes an e.\(|uisite spindle-shajx! in cross sec-
lion, with somewhat metre convex dorsal surface, and tinally
limits sharply dorsally an<l somewhat nu-dially th(( whole hasis
pediiiuiuli. It is larj^'est in cross see^tion at a hivel just poH-
tcrior to the corpus (uammillare. .Anterior to this y)oint it he-
conu's stmiller, hut remains spindle-shaped in cross section and
tinally disappears in plaiu-s corres[)on(linf; to the anterior part
of the corpus nuimmillar(\ The dorsal surface of Luys' hody
is turn(^d toward tint zona iucerta, while the; ventral, some-
what less convex surface, is turned toward the hasis peduncidi
and tlu^ internal capsule. The nucleus is inclosed somewhat
imperfectly hy u dorsal and veutial white capsule, tint two eom-
\\\}f in eontiKit with oiu- another at the circular edfre of the
iiiuleus, espoeially at its anterior and posterior extrciuitics.
XutiruH hi/fHillitiliiniiftiH. hmtkiim fnriliilhifis liiti-niliH.
lAirvt's l'\ltl n '* /turn rt'lit'itloris tttillt'fHrht'rht}.
\'<}itri<nhis tirtiiiK
,\t(i.i!<(i iiitiiniiiliii. , ,. ,..,..
Fiisiiiiilils tliiildiiioiiiiiiininlltin'H ■; "j^j^t v"''i'<f>'^'v'
ii-in, <r.i;//,/i. j.; r-' ..;- ^^^. v,:*"/
\'iiiliirnlii.i trrtiiilt.--'' ' V
Fiisrii\il\is lliiiltniiiiiniiiiiniilliinn.--'
^', , ",. -'V."*\'i./ ('<l]IH\llll llllrlllll.
"TriirtiiH iiiitirim.
fui/nis iiKiiiiiiiilliirr. lUlsis jiiiliniriili.
I'Ui. V.iH. — ('"ritiilal sccdidi lliriiiifjli the tiritiii sliiii. lAI'Icr A. Fnicl. Arili. 1'.
I'sycJiiiil., |{(il., IM. vii, IsTT, Tar. vii. Vin. Ui. i
As rejjards the nuclei of the thalamus, l-'orel follows closely
the(le.scri[)tionsof Hunhudi, whodividetl the thalamus (aside from
the pulvinar) into three f^ray nuclei, which correspond to what
we now desijjnato as (I) the nucleus medialis thalami,* {'4) tlu;
nucleus lateralis thalami, f ami (){) the nucleus anterior thal-
* nunliiclrs innrrer Kern, liiiys' ventre mni/en.
f liunlacli'-* (ifitssrri r Kirn.
. i
!t
i
<!T4
TIIK NHUVors SVSTKM.
^ 1
»l 1 I
■^ l|
iimi.* In lulditiou lu' roco^^iiizcs the existen(^e of Luys' mi/rr
nie(U((u., a nucleus hidden by nmny niedullated fibres lyinf;f deep
in tlie substance of the tiialiiinus between the nucleus ruber,
tlio nucleus niedialis thalanii, and the nucleus lateralis thalanii.
Von Tschisch,f in IcSlStJ, described an adtlitional nucleus in the
thalamus situated just dorsal to the red nucleus and lateral
from the fasciculus retrotlexus Meynerti. This mass of j^ray
matter, which in r((ality belongs to the nucleus lateralis
thalanii (according to von Monakow to the ventral grou]) of
nuclei), is concave above, and in the concavity rests the vcntrv
median of Luys. \'on Tschisch calls it the srhnlenf"t)rnii(jrr
f\(ir/if'r; Dejerine writes of it as the iioi/ttK st'tnilinidin' ifc
Flrr/isif/ ; and von Kolliker calls it the nucleus arcuatus of i\w,
thalamus.
Dejerine, in a beautifully illustrated publication, describes
and pictures a large number of sections — coronal, horizontal, and
sagittal — through the cerebral hemispheres, from which the stu-
dent, in working through the region of the thalamus and hyjx)-
thalamus, will find much help. An extremely careful and de-
tailed description of the thalamus and hypothalamus has been
given to us by von Kolliker in the last edition of his text-
hook ; it is of especial value in that it is accompanied by a large
number of exquisite illustrations.
Von Kolliker J accepts Forel's nomenclature as regards fields
II, II„ and Hj. He calls Fchl 11 the "tegmental bundle of
the red nucleus."* This splits into two parts: a dorsal })art,
Forel's Fvhl //,, which he desigiuites as the "• tegmental bundle
of the thalamus," {| and which he finds vanishes in the lamina
medullaris lateralis and in the nucleus lateralis thalami ; and a
ventral part, Forel's Fchl IL,^ which he calls the " tegmentid
bundle of the lentiform nucleus ;"*" this goes tlu'ough Luys'
body and the cerebral ])eduncle to become lost in the nucleus
lentiformis. He separates the upward continuation of the
* Hurdacirs oberer Kern, Ijiiys' centre (in/i'n'i nr.
\ VDii 'rscliiscli. W. F. I'litcrsiicluingi'ii ziir Aiiatoiiiie tier (ifliiriiuaii-
glieii (lus ^h'lisclicii. r.iT. (1. iimlli.-pliys. CI. d. k. siiclis. Gesellscli. d. Wi.-^s-
ensch., 188().
t O/,. r//.. S. 4.']4.
* /fitiihi'nhi'inile/ ilex rof/ien h'erne.f.
II fhtuJienhi'indel de-t TlirihiniK.i.
^ irnnhitilii'indel dix Lln-^iiilceriw.^,
M. '
(ii{<)riMX(i AM) (H.MNixc 'nxii-yniEu <>f xkuronks.
075
miMliiil U'lniiiscus from Fvld 77, and stutoa that it is situate*!
liitcrally from it.
'riic ui)\vard coiitiiuiiitioii of tlio fasciculus lonj^Mtudiiuilis
mcdiaiis is discussed at leiij^th hy von Kolliker.* In liis opin-
ion, instead of breaking uj) in tlie iiudeus of the posterior
commissure, the medi ' portion of the fascdculus juisses ventral-
ward into tlie hypothalamus, and tlien passes dorsal from tlie
cor])ora mammillaria to enter a commissure formed by the
])undles of the two sides. A second ])ortion, includitif^ the
majority of the fibres, mixed with the arcuate fibres whi<'h sur-
round the red nucleus on its medial and ventral as])eets, be-
comes lost beneath the same, so that it can not be followed
further. Althou<fh he fornun-ly believed that it represented u
crossed central sensory path, he now, as a result of the studies
of van tJehuchten, Jleld, and others, is inclined to think that
the majority of the fibres are descending, having their origin
either in the thalamus or in the central gray matter of the third
ventricle.
With regard to the bundles passing cerebralward from the
region of the red nucleus, von Kolliker thinks it is difficult to
state how many of them come from the brachium conjunctivum,
and how many of them correspond to longitudinal bundles of
the formatio retiiuilaris.f lie agrees with Forel in thinking
that the bundle designated by the latter BA Th goes over into
Feld H and splits. His descriptions of the fibres from Feld
//, ami from Fchl //. agree in the main with that of Forel.
The bundles from the red nucleus itself tend, von Kiilliker
states, to surround the rottrc nu'diaii on its ventral side, and
are continued in the form of an arched platelet, which, cutting
through a radiation of the thalamus parallel to the lamina
medullaris lateralis, turns doi'salward and l)ecomes lost before
reaching the dorsal surface of the thalamus. This arched
plate of fibres is seen in frontal sections farthe; forward at
the beginning of the lamina medullaris jnedialis. Parallel
with this plate there go strojiger fibre bundles from the ri'd
nucleus through the mednllated radiations of the lateral nucleus
of the thalamus, representing for some distance a special inter-
nu'diary lamina medullaris (Fig. 4o!)). Between these two ra-
diations from the red nu(deus is to be found a stnall field of
I I- (
Op. cif., S. 4:!S.
t Op. cH., S. 4")4.
l!
'! -^.
L ii
. I
r
i'
{\H>
TIIK NKIfVors SYSTKM.
^M-ay substuiKP, the nucleuH arcuutus, or svhtih'nfi'irmiger K'6rj)vr
of voji Tschisch.
Von Kollikcr in liia toxt-book {jivos further iin chibonitc^ do-
scription of tlic «lilT('n'iit miclci of the tliiihuiuis, in which lio
conipures his finding's in Weigert preparutions of the brain of
l''i<i. Jliii. — Kroiitiil scctiiiii tlii'ipii'_'li the liniiii stem of man. 'After A. viin Ki'il-
likcr. lliiiKlliiicli (liT (iiwcliclcliic, Lfipz., ltd. ii, Isits, S. W.\1, Fi<;. <i(>0. ) n,
ii(|Ui'<lucti's ccrcln-i ; C'l, ("ipsula iutcniii ; Ct. nucleus iiyi)(itliiiliiuiicus icoriius
Luysi); Ty;, ('Kniniissuni iinstcrior ccrctiri ; /•'.)/, fasciculus rctnitlcxus Mcy-
iicrti ; Hhji, ^lolius piilliilus of uuclcus Iculiforuiis : I. mm. lauiiiia nictlullaris
liH-dialis; l.ml. lamina mcdullaris lateralis; A7. nucleus lateralis tlialami;
A'«i. criitrr mrilimi tif IiUys(vou Killliker's uiK'leus inedius tlialami): .\iiil,
iiuclcs's meilialis tlialami; Sure, nucleus arciiatiis i.>((7i(»/('»/Viy)H«;(';' Ki'irin'r nf
HeciisiK and von Tscliiscli ) ; A'r, nucleus nilier ; /', initameii ; /'y;, liasis
pediiiiciiU ; (^i(, colliculus superior; >». siilistantia nifjra ; Tli, thalamus;
Tr.o., trai tiis opticus.
man tind iinimals with those of Xissl in the thalamus of rabbits.
As is well known, Xissl * has made a very thorough study of
the nuclei of the thalamu.s in the rabbit, and has isolated, ac-
cording to the form and grouping of the cells, some twenty
different nuclei. In brief, his description is as follows : In the
* Xissl, F. Tagebl. d. 63 Vorsaininl. deiitseli. Xattirf. u. Acrzto, Ileidelb,
(188»-'90), S. 509.
■i^
u
%i
({Ii()in'lN(J AND CIIAININCJ 'nxJKTlIKU OF NKUltONKS. (577
Hart of (lio tlialarniirt projecting i!io.st anteriorly is situated an
anterior nucleus which must he (livi(hMl into a smaller anterior
dorsal and a larger anterior ventral nucleus. The latter shows
a further (lit!erentiation, so that one oun di8tinf,'uish distinctly
in it a dorso-medial part from a ventro-lateral part in which the
cells are yiuch (;los(>r tof^'ether. Medial from the anterior
nucleus is seen tin; rather simill anterior medial nucleus which
lies like a cap around the middle medial nucleus, 'i'he latter
is u larjfe nucleus situated close to the iniddh^ line, aiul visihlu
for as much as half of the lon<,'itu(limd extent of the thalamus.
N'entral from the anterior niu-leus lies the nucleus of the retic-
ular zone {(lillcrxrliirlil). The first to ajjpear in a frontal
series of sections is the ventral nucleus of the reticular zone,
which terminates ntedially at the transverse section of the
columns of tlu^ fornix; laterally it adjoins the lateral nucleus
of the reticular zone, an insij^nilicant nucleus. Metween the
ventral nucleus of the reticular zone and the ventral anterior
nucleus lies the dorsal nucleus of the reticular zone. Close to the
middle line appears a narrow cell plate of spiiulle-shaped cells,
which Nissl calls the "nucleus of tlie middle line," without
(juestionins whether it belongs to the thalamus or to the stratunj
griseum centrale. This nucleus of the middle liiu* is invadeci
by the middle medial niudeus, which cjuickly approaches the
middle line, so that one part of it comes to lie dorsal, another
ventral from the middle medial nucleus. 'J'hese two parts
quickly spread out lateralward, the dorsal more than the
ventral.
In a slight lateral projection of the thalamus is situated the
anterior extremity of the lateral nucleus. First of all comes
the anterior lateral nucleus, whicdi occupies almost two thirds
of the longitudinal extent of the thalamus and which increases
in size as the anterior nucleus diminishes. It has the form of
a sector of a circle, the curved line of which forms the lateral
curve of the thalamus, the medial radius of which adjoins the
anterior nucleus, the ventral radius adjoining the dorsal nucleus
of the reticular zone. Around the angle formed by the ajn'X of
the sector there is deposited a )uirro\v row of cells also in the
form of an angular mass. One series of these cell groups lii's,
therefore, between the anterior lateral nucleus and the ventral
anterior nucleus; the other between the anterior lateral nucleus
and the dorsal nucleus of the reticular zone. Since this nu-
\i
I
♦;7h
TlIK NKIIVOIIS SYSTKM.
'
clous contains the largest cells which occur in the thulanuiH,
Nissl calls it "the large-celled nucleus" of the thalamus.
As the anterior uucUmis vanishes, its place comes to l)e occu-
pied hy the posterior medial nucleus, a larj^e nucleus which
laterally abuts against the anterior lateral nucleus. Besides,
betw' on the ventral and the dorsal nuclei of the reticular zone,
which are both displaced nuirkedly lateralward, a new nucleus
develops, whieli had hitherto never been mentioned. Nissl
calls it the ventral nuch'us. It is very large, and o(!cupies
about the posterior half of the longitudinal extent of the thahi-
mus. This nucleus is very difficult to describe, because tran-
sitions into almost all the other nuclei occur. However, it is
not difficult to determine in it three cell groups of definite
arrangement. The lateral ventral nucleus possesses spiiulle
cells, the medial ventral nucleus large cells, the dorsal ventral
nucleus, on the contrary, small cells. The ventral nuc^leus in
its totality represents a triangle, the base of which rests upon
the lamina medullaris lateralis.
Soon after the ajjpearanee of the lateral geniculate body the
posterior lateral nucleus develops, which contains much smaller
cells than the anterior lateral nucleus. The posterior lateral
nucleus is situated between the lateral geniculate bodies and
the anterior lateral nucleus. In these frontal planes there are
to be made out in addition only some remains of the ventral
nucleus of the reticular zone, the ventral nucleus, the posterior
medial nucleus, and the nucleus of the middle line, the sepa-
rated parts of which have again coalesced through the disap-
pearance of the middle medial nucleus. Besides, in these
planes, one finds also the ganglion habenula3, in which a more
distinct lateral nucleus can be made out, containing scattered
larger cells, and a medial nucleus with cells pressed close to-
gether. While the lateral geniculate body becomes mucdi larger,
the other nuclei diminish in size, and there appears between
the two lateral geniculate nuclei and the ganglion haben'ihe the
posterior lateral and the posterior medial nucleus. The latter
shows scattered cells, which go over quickly into the stratum
griseum centrale, while the former is a larger nucleus contain-
ing cells closely massed together, which stain feebly. With
the appearance of the posterior commissure and of the medial
geniculate body the posterior lateral nucleus alone still remains
large, while only remains of the lateral geniculate body, of the
UUori'INCi AM» CIIAINIXO ToOKTIIKIl OK NKl'IfONKS. (;7:»
postorior nicdial »ui('I«'tis, iiiid of the vciitnil imclt'UH arc visihlt'.
Nissl bclit'vcs tliiit (iaiiscr is iiicctricct wliidi he states that tho
posterior miclcus goes over into tlu' medial geiiienlate l)ody,
and iiolds that von Monakow is tilsu wrong in thinkin<; that
this nucleus iilso j^oes over into the lateral geniculate body,
lie states that the posterior nucleus is always sharply separable
from the two geniculate ixnlies. The lateral geniculate body
consists of a dorsal nucleus and a ventral nucleus. In the dor-
sal nucleus, again, one otin make out a hiterul-dorsal nucleus,
which, in contrast to the dorsal nucleus propi-r, possesses far
larger cells. This lateral-<lorsal nucleus is identical with von
(Judden's centre for the pupillary fibres. The ventral nucleus
of the laterul geniculate body can be distinctly ditterentiatod
into a ventro-medial nucleus and a ventro-lateral nucleus con-
taining cells of a ditferent sort.
According to von Kolliker, Nissl has. since the publication
referred to, given u]) his posterior medial nucleus; accordingly
he designates as the " posterior " ni'.cleus the mass of gray matter
which he formerly called the "posterior lateral" nucleus. lie
adds still another undescribed nucleus, which he states is situ-
ated close to the tivnia thalami, and contains numerous spindle-
shaped elements.
For the sake of convenient referencfe, I have arranged these
nuclei described by Xissl ii: tabular form.
XUCLKI OF Till-; TlIALAMlS OT TlIK UaBHIT (ACCOHDIXli TO
Xissl).
I. Autcriar Xiirkiis.
(a) Dorsal nucleus.
(b) Ventral nucleus.
a Dorso-medial part.
/3 Ventro-lateral part.
II. Medial Nnclcn>t.
(a) Anterior nucleus.
(b) Middle nucleus.
(c) Posterior nucleus (since given up).
III. Xnr/ci of the /icfirnhtr Zone {(r it fersrhir/i kerne).
(a) Ventral nucleus.
(b) Lateral nucleus.
(c) Dorsal nucleus.
n.
%
<?80
TIII<; NKRVOl'S SYSTEM.
IV. Nuclenn of Middle Line.
(a) Dorsiil part,
(h) \'(Mitral part.
\'. Ij((tc>'(il Xiirlrns.
(a) Aiiti'rior miclous.
(b) Posterior nucleus.
\'I. Vent ml Xitclvus.
(a) Lateral nucleus.
(b) Medial nucleus.
(c) Dorsal nucleus.
\'Ii. /'(i.sfrrii)r Aiirlriis (now desigiuited tbe posterior lateral
nucleus).
\'III. I'liiKdiu'il \i(r/('iis (close to ta'uia tlialanii).
\'on Monakow* bas carefully studied tbe nuclei of tbo
tbalainus in buinan beinj^s and in bi<i;lier luaininals, and bas
compared bis results witb tbose obtuiiu'd by N'issl in tbe rabbit.
He widens tbe cla.ssifieation wbicb dates from Hurdacb's de-
scri])ti()n {i'i(fr siijira). It would take up too niucb space to
introduce bere a detailed account of bis findings, but tbo fol-
lowing^ table will fjive a fair idea of bis classification of tbe
nuclei as observable in a series of sections in luiman bein<fs, It
is to be especially noted tbat von Monakow adds a distinct ven-
tral <iroup of nuclei to tbe older descriptions. Tbus, tbe lateral
nucleus of tbe tbalamus (of Hurdacb) is divided by an arbitrary
plane into two balves — one dorsal (lateral nucleus of von .Moiui-
kow) and one ventral (belonging to von Moiuikow's ventral
group of nuclei).
NucLKi ov Thalamis in Human liiciNds (accoudino to
VON Monakow) (Figs. 440-44f).
1. .inferior XiirlcHS.
(a) .Vnt. a — tbe main nniss (Fig. 444).
(b) Ant. c — an accessory anterior nucleus (Fig. 444).
II. MrdidI Xiiflt'iis.
(a) Med. a— tbe main portion consisting of tbe anterior
and medial portions (Fig. 44'i).
(b) Med. b — tbe irn/rt' ini't/itni of Luys (Fig. 44;i).
0/1. rit. Arch. f. I'syiliiiit. u. Ncrvcnki-.. BitI., lid. xxvii.
OllOUlMNd AM) CllAlNlNii 'nxiKTIlKU OK NKriJONKS. «;si
III. f.<ifrnt/ XiirJriis {V'l'^. [l\) — tlH> dorsal liiilf of Hurchiuirs
liiLcnil lUK'.k'Us of till' tluiliumis.
l\'. Vent ml (I roup of Xitrln'.
(a) Vent. ant. (Fig. 444) — tlu' anterior ventral nucleus.
(I)) N'eiit. a (Kij^. 44'^*) — the middle ventral nueleus.
(c) Vent. 1) (Fi<f. 44:.') — the nu'dial ventral nucleus {sc/u/I-
ciifonnif/rr /\i'ir/>»'i' oi' Klechsij^and von 'i'schisch.
(d) \'ent. c (Fig. 441) — the lateral ventral nucleus.
V. Xv dpi of the licfiruhtr Zone {Hittersrhichthvrne^ Fig. 44:5).
\'I. I'ostcrior Xi/rlr/is (Fig. 441).
\I1. /'////•///r//-(Fig. 440).
■ '"^
' '
'^*''
In the cat von Monakow describes, in adtlition to the nuc
above nu'iitioned, (1) a nucleus tdif. /», ('-i) a nucleus inrii.
and (;{) a nucleus met/. <• (nucleus niagnocellularis of the nu'd
nucleus), lie divides his lateral nucleus into two parts, /(//.
I'nlrniiir.
J Cerium (iininilatiini iiinliiili'.
', ' liidchiiiiii iiii(iilii<ii)iiiniiiii iiiftriiis.
lei
(I.
ial
Aijiifdiirtiis cerebri.
> Deciissiitii) hnichii
coiijiiiiclivi.
Corpus geniciiUi tit III latenile. |
Niicli'itu iinntfriiir Ihiiliiiiii
FlQ. 440. — Frontal section tliroUKli a normal liiinian hrain a( tlii' Irvrl i i dec
satio liracliii conjunctivi. lAI'tcrC. voii Monakow. Arch I'. I'.syclii.il, 15c
15(1. xxvii. IS!!,"). Tat', ii, Kii;. 10, i s,, lemniscus superior [iihrrr SrI Ivifi'i ;
main porlion ol' lemniscus meilialis i lldiiplllicil ihr Srlilfifr}isrhic}{l ) , .r, \
while niattir ol' iatenil jjeniculate liody.
it(
tis-
rl.,
•S.
■ml
aiul /(il. /j. The uiH'lei of the reticular zone (^'///r^,^77//^///) he
divides into an anterior and a posterior group.
Tscheriuak * speaks of a medial ventral nucleus in the
thalamus which is identical with the sc/ifi/riifi')niii(/rr /x'or/nr of
I'Mcchsig and with von Monakow's rciif. h. The middle or cen-
tral nucleus {rent, a) and the lateral ventral nucleus or reii/. r
* 'I'sclienuak, A. I'eher den cetilrah'n N'erlaiit' lier iinrsleifjenilen ilin-
t iiiiilmliiu'ii nnd deren Hcziclinnu'i'ii /ii di-ii l>atineii ini N'order^ejieii-
.straiig. Arch. f. Aunt. ii. Physiul., Aiiat. Ablli., Leipz. (1S!»S), S. ;;!»l-(()0.
45
V
682
THE NERVOUS SYSTEM.
of von Mojiiikow are grouped together by Tscherniuk and called
the " ventral nncleus in the narrower sense." * He describes the
srhah'iifuriniycr K'urper as spreading out laterahvard and going
over without sharp limit into the nucleus lateralis thalanii. It
Xuch'Ua posterior fluilaini. ,
,i\ucleHareiitrnlia lateralis thalanii.
I'ulviiiiir.
('iillirnlu.i sii/terior.
'*^ ji.,"' ' ' N, / i'oiiiminsnra posterior cereliri
iSJl '*«-' J, •"•■- ) / < Aiiueiiuetiiscereliri.
:^^J f^^/^rh'' y ^''ji: . • '.•■*iii^:^'' Fasrirvliis hmqi
CorpuK geniciilatum laterate. '
Corpus genienlatiim mediate.
Lemniscus.
< V 'Si(l>sttnitia Jii'gra.
I /
' l,emnisrii,s iiiedialis.
fiasis peilunciili.
-. "Jira chill III coiijiiiictivuiiif
et nucleus ruber.
Fl(!. 4'tl. — Frontal sci'tion tlinMiRli a normal luiiiiaii br.iiii at level of iii)i)er
extremity ol' corpus K''"i<'iiliitiiin iiiediale. (After t'. von Monakow, Areli. f.
rsyehiat., Herl., M. xxvii, IHitf). Taf. ii, Fif;. 13.) .c, lateral white matter
of lateral geniculate body ; ;/, lateral white matter of pulvinur.
is divided by bands of medullated fibres into a number of small
groups of ganglion cells. Under the term Thdlamnsmnnmo
Tschermtik destjribes the more or less egg-shaped total mass of
the thalamus which, latero-ventrally and hiterally, as far as the
floor of the latertd ventricle, is surrounded by a lamella of gray
substance, the (Htferxrhirht or zoiui reticularis. This ThttUt-
nmsschale^ as Tschermak prefers to ctill it, is continuous with
the anterior extremity of the substantia nigra and with the
corpus geniciilatum mediale. Ventral from the ThdhimiixsrhaJe
lies the nucleus hypothalamicus (corjjus Luysi) covered by its
dorstd white matter, the so-called Fvhl IL of P'orel. In man
the nucleus hypothalamicus lies upon the dorsal surface of the
basis pedunculi, but in the cat it passes through the latter as a
coarse-meshed fnimework of gray mtitter. On the lateral side
of the ThahimnxKclKtlv tire situated the fibres of the capsula in-
terna (tlie direct continuations of the white fibres of the basis
pedunculi). Itiasmuch as the ThdlnmussrhaJc leaves the Thal-
nnnt.'onas.siv uncovered only on its medio-ventral surface, a
groove is formed through which fibres pass, on the one hand, be-
tween the Thuhtinnsscludv and the T/iahimn.stnu.s.nr, and, on
Ventrnlkern im enyeren Sinne.
(JHOUIMNd AND CHAINING TOGETIIKK OF NEURONES. (',83
the other hand, into the gray matter of the Thalamusschale and
of the Thalamn.wiUKsiv themselves. Accordingly, Tschermak
designates this the Ili'lns tJutlami. The fibres which enter the
thalamus run in company with other fibres which leave the
thalamus, in places forming very definite bundles which, run-
ning through the gray matter, divide the thalamus up into a
number of nuclei or groups of nuclei.
Tschermak's description is so clear and agrees so well with
what one actually sees in sections through this region that some
of its main features may with propriety be introduced here.
Numerous bundles can be seen passing out of the hypothalamic
region and radiating through the hilus thalami into the thal-
amus itself. These include the remains of the lateral lemniscus,
the medial lemniscus, and the radiations of the red nucleus.
Some fibres, however, approaching the hilus scarcely enter it,
but turn aside again to break through the TlialumiiHschule and
Lamiiiii iiiciiiilldris )iie<li(i.
Luminii ine(lull(tris mfdinlis.
Aucleun tiifilidlis thtiluiiii ib)
I I (centif Jiiidiiiti)-
Capxula interna.
Nucleus Ifuiiformia.
ynclvHS medialia thalmni (a).
.T(e.nia thalami.
11'/ <» .... KKnia inaiami.
! * / T
1 iV'fL t iMiiiiiia )iif(liillaris tlialaiiti.
V"-"-
j" \ ^^ Xucleiis ni
/ ; /
\'eiilrirnln.'ilateralis{cor)iu inferiun). j ;
Nucleu.i rei)tr(ili.i flalaiiii (ii). ■'
A'i((7('«s ri-iitralin thalami ih).
■ ^"^ -?v, ■:--.V ; t^^:,i,i^-^'''^ ,- Xitcleun ruber.
V™^. -^ •'•\i.:-Fa.irirul us relriifle.ius
(.l/<'i//i(/7i).
n f J/'^x ^~iS' l^''lllmTli'''-''Y ^^raseioihta ])eihiucuh>iiiai
fl v/^) 7^\ ^^ H'^ ft ■•'i/i tuillariK, imr.s leijiueutal
Xuch'us hyiiiitlialaiiiicu.^
{vorjnts Luysi).
/iVi.s'/.s' luihtufuli.
Fk;. 442. — Fnintiil soctioii tlir(iui,'li a iiorniiil Imuian liraiii at the li'Vcl ul' tlic
lower v\h\ ol'tlic nucleus liyimtlialaniicus. (After ('. von Mouakow, Arcli. f.
I'syeliiat., Herl.. Hd. xxvii, ISitf). Taf. iii, V\fi. '^0.' a, dor.sal wliite matter
oC nucleus rul)er : fi. vt'Utral \vliil4- matter of nucleus rulier; y. lateral wliite
matter of nucleus rulier.
bend around past the nucleus hypothalamicus to arrive in the
basis pedunculi. In man the fibres of the niiiin mass of white
matter in the hypothahmiic region, at least those most ventrally
situiited, do not pass through the liilus into the thiilamiis.
These ventral fibres, on the contrttry, rtiii iilong the ventral sur-
face of the Thdhimnxsrhale — that is, between this jind th(*
■ I _.
!' ;
^Ir
^ i
I
684
Till': NEin'ors svsthm.
nucleus liypotlialaniicus, formiuj? tlu' " dorsal wliito matter " of
the hitter {Felt/ JL of Forol). They pass lateralward into the
basis pi'dunculi, and so, accord injjf to Tsclicnnak, represent
genuine diret^t liypothalaniic fibres from tlie liypotliulamic
yuclettH lutirdli.i thiihniii.
; ,yiaU-nn iiiili'iidf tliiilitiiii.
Cnitniild ititi'iiKi. '.'■'■
A*- V"1'X' ' ^^- ■"">, .■Lnininit iiicilKlhiris mcdialis.
> "'•'"■IF '*' >'
Xoiw rctiriilinis {(ritter- — ,;.J
achicht). i \S
/ '^"■^
^ ,-"' \^ — Tainia thalaiai.
Nucleus le)it if ttrmia. '■ ^^^^tX-' ^ \
I ' "JvTM^Sfe^. ' " ■ "-■ . ,\ FasciciilKs lliiiltiiitii iiiamiiiil
Xiirlcus reiitrali.'i thiiliimi •-'"
(ant.).
Anna letifirnlan'n, purs ~'\'
(Idisitlis.
■^^i%c^
>is-r.-. ^'' .' laris {I'll (I il' Azyri).
\ >v
, Ford's Felil llj.
-S>y'"^' 7 - 'i . /t^.'.Columnafornuis.
Commissiirn anterior cerebri.' } \
Auxn lentirularis (ijiirs veiitnilis). •
I'eilniiruliiK cerebri.
Kk;. 443. — Frontnl section tlirmi'ili :i iiDniial iKiinim brain at tlu' level of the
ansa ientieiilaris anterior to llu! nucleus iiypotlialatnicusi. i After ( '. vou
Mouakow. Arch. f. Psyehiat., Herl., IM. xxvii, lH!t5, Taf. iii, Kij;. 28.)
region to the basis pedunculi. Speaking purely topograpliically,
these direct fibres represent a continuation of tlie bundle which
in lower regions, especially at tiie level of the eolliculus su-
perior, can be seen passing over from the area occupied by the
lemniscus medialis ventro-lateralward into tlie basis ])edunculi.
These are the fibres which Flechsig designated the Fusssrlilrifc
or PediDiriilus/trfih'if)', and they are, Schlesinger believes, prol)-
ably identical with the fibres of the lateral ])ontine bundles of
the lemniscus described by the latter author.*
* Die /(ifi'irile pontine lii'tiidcbi iler Srhleife. With repird to the Fiisfi-
schleife, Fkn-iisig is now of tiie opinion that its fibres are not anioiiti' the
contripctal fibres of tiie ienuiiseu.s ineilialis, but, on liie contrary, represent
(lescemliiiij; (centrifugal) fil)res wliicii pass downward with tiie filires of the
pyramidal tract and, entering in all jirobability into relation with the most
medial bundles of tiie lemniscus, pass with the leinniscns medialis liy way of
the tegmentum to terminate in the iinelei of origin of the motor cerebral
nerves. On the contrary von l')c<'literew i)eliev(>s that Flechsig's Fi(.-<.-i.ir/ileife
is identical with his (von Hecliterew'.s) zerstrenle ficct',isori.s(lie JJiiiiilel. pari
of which he considers to he centri]ie*al, jiart centrifugal (lieituiigsiiahnen. 11.
Aun.(lSS!)). S. -J:!! ;)14. :!!!»). Schlesinger's buiiilles arc considered on page
2;{7 of von Bechlerew's book to correspond rather to tiie inediale Sc/ihife
than to the zemtreufe accensorisvhe Schleife.
OUOrriXO and CHAIXIXCi TO(iKTIIKR OP NEURONKS. (585
III iiiuii Forel's Fchl ll.> is in contiict at its iiiitt'i'ior ex-
tremity with the cornpact ansa leiiticularis {Linsenhi'nisrIiliiKje
of Flcc'lisijjf), wliicli, ajtpari'ntly bojjfiiinin^f (or I'lulin^f) in tlio
nucdi'us U'litiforniis, circlt's aroiind the niodio-ventral hordor of
the basis pt'dunculi and, in connection witli the so-called medial
])eduncle of the thalamus, radiates into the most anterior
ventral region of the thalamus. Von Monakow distinguishes
in tlie ansa lentioularis three principal bundles: (1) A dorsal
l)undle which goes from the globus palliilus transversely
through the peduncle to go between the (littersrhicht and the
nucleus hypothalamicus. This bundle corresponds to the above-
nu'ntit)ned hypothalamic fibres (Forel's Frhl //o, dorsal white
matter of the nucleus hypothalamicus). In man the fibres are
much more numerous and arranged in the form of a much
more compact bundle than in the cat (Tschermak). {'I) A mid-
dle portion running medio-ventralward from the fibres of (1).
This middle portion of the ansa lenticularis forms the lateral
and especially the ventral white nuitter of the nucleus hypo-
thalamicus connecting this body with the nucleus lentiformis.
(;>) The ventral part of the ansa lenticularis runs between the
■,Vi?N 'V. / XwUiis l<it('i(ilis thiiUtiiii.
Capsnla interna.
' $*\v^~T'i^ V>i' / yiicli-iin (iitlirior tliiiliimi (<i).
iV':i\»*'.^'>~^jf-~T ' ~v y Cdiisiild ifiiti'iitis iiucl. aut.
:iv*->'>' '^v ' ■ • •» • - /Tiiiiin thttlaii\i.
'■ ' ' Stnttitiii (/I7.sci(m centriilc.
Xtuh ».< ieiitr(tlis.--'\
thdliniu l(^l^).
Piildiiien.''
(;l(ihii!< jKiltidiis. pars'
Idtvriilis.
(ilohtis pallidiis. piirn nieilialin.
Ciimminsiint (interior crr<liri
'~i \. ■'■'■Ji. '^ • ■ j >f''"f'(m (/I7.SC
(iliiini midialis.
Cuhiiitnti furnicis.
' .liisd h'liticiildri.i. jMirx ventnilii^.
Via. 141. — Fnintal section tlintUKli ii iKiriiiiil Iniiiiiiii lir;iiii at level of aiiteriiir
part lit' tlialaiims. ' Al'ler ( '. von Moiiakoiv. Anli. f. I'sycliial., Herl., lid.
xxvii. lHtl.1. Taf. iv. Imk. :W. •
pedunculus cerebri and the tractus opticus medialwiird and
sends some fibres into the commissura hypothalamicii media of
Meynert, but the main mass of its fibres form the so-called ansa
peduncularis * which exteiuls to the most anterior ventral part
of the thalamus of the same side.
Ill
:i^
, -(I
m
* ITirHHchenkelsMiniie of rieelitsip.
■
If
Hill
*■ I
686
TIIK NKIiVOlIS SYSTKM.
It is von Moiiiikow's opinion tli;it i\w libros of tlif dorsul piirt
(Kort'l's Fcid II.,) unitt' with tho niiiin iiiiiss of tiie vontnil part
of till! iiiisii liMitifuliiris, and that iU!conlin<^ly the ausii h'utic-
uhu'is is in tiio main a connoctinj^ hundh; ))ot\vo('n the nuch^iis
h'ntirorniis and the anterior ventral parts of the thahiinus (and
also the tnher cinereuiii), some of the libres hein^' interrupted
in the nuelous liy{)othalamieus. FUudisif^ has come to the eon-
elusion that there is a relatively important connection, partly
direct and ])artly indirect, by means of the nucleus liypotha-
lamiciis, between the luudcus lentiformis and the thalamus.
This is broujjfht about, however, he believes, oidy by way of the
middle and the ventral part of the ansa lentieularis. The
dorsal part of the ansa lentieularis {Fdd I/., of Korel) repn;-
scnts, on the other hand, acconlinj^ to Klechsi«r, the eontiniui-
tioii of a larjfe part of the cerebellar tc<^mcntal (or conjunctival)
radiation. Tlu! fibres go into the nucdeus lentiformis and thus,
according to Flechsig, represent a radiation from the brachium
(ionjunctivum into the nucleus lentiformis.* Another part of
this radiation, however, goes by way of the red luudeus through
the hihis thalami into the ventro-lateral group of nuclei of the
thalamus.
We may now consider scriathn those bundles of centripetal
fibres wliicdi, ])assing into or through the cerebral peduiude,
may be concerned in the forwarding of soma>sth(!tic im|)ulscs.
These are [a) the lemniscus or fillet, {h) the fasciculus longi-
tu<nnalis medialis, {r) the forniatio reti(!ularis alba, and {d) (!er-
tain fibres of the brachium conjunctivum and radiations of the
nucleus ruber.
((II The Lemniscus or Fillet.
The term lemniscus laqueus, or fillet, (Cierman Schlrife,
French ruhan de licU), was first ai)plied to that triangular area
on the lateral surface of the isthmus rhomhencephali, which
s(>paratcs the braidiium cotijunctivum from the surface (Fig.
445). This area, now called the trigonum lemniscii, corresponds
to what is now known as the lateral lenniiscus.
With the progress of anatomi<!al knowledge the complexity
of the nerve paths comprehended in the term lemniscus has
rapidly grown until at present the beginner often has difiicudty
* liinih'iirni-Linxi'iiki'ruKtrttliliniif.
(}ll()UPIN(} AND CIIAINING T()(5KTIIRIl OF NKUItONKS. (JK7
ill iiiHiiTstaTuliiifr the moiiniii^ of the various iiaines a[){)li(Ml to
tho (iitrcrcnt portions, espcMnally siiu;e, unfortunately, the sunie
term lias hccii used by different authors for ilesignaLing entirely
Cgi Pul
l-'io. 445. — Istlmiiis rliinnlii'uccpliiili scrii in profile, i .M'tcrJ. Dc.jcriiic, Anatoniie
<lcs«'ciitr<s niTvciix. t. i, Paris. Isil5, p. ;5-^S, Vi-x. V.)2.) HI I. tnutiis (>i>ticiis ;
}ir()it. liracliiimi <iiia(lrif;«'iiiiiuiiii siipcriiis ; ll>'(/i>, bracliimii (|ua<lri-
Kciiiiniim iiifcriiis; Cijc, corpus k«''I'<'"'iiIi"ii latcnilc ; (';/('. corpus «'"'''■
ulatiiin iiudiah' ; CliII, cliiasiiia opticiim ; Crsl, corpus rcstirornic ; Flu.
funiculus lateralis of nietlulla oliloufiata ; fan. lilu-n- arcuata- externa';
/•'()/(, tilu'a' superticiales pontis; ()), corpus pineale ; .\ll, N. oi)ticus;
Of, oliva: /', peduiu'ulus cerebri; I'ciii, liracliiuni pontis; I'c.s. l>racliiuMi
cou.junetivuin ; /'«, pons \'arolii ; /'»/. pulvinar ; /'//. p.vrauiis ; ?^((, colliculu^
supericu-; (Jji. eolliculns inferior; /,'/, trifjonuni leninisei ; lliii, lemniscus
nicilialis; v/, sulcus lateralis ; 77;, thalamus ; 7';"), tiiMiiu ])(>litis ; 7'/)^ tract us
lieduiK'ularis trans vei-sus.
dilTereut ptiths. The two priiu'i]ial portions of the h'nmiseus
are (1) the lemniscus lateralis or lateral fillet (infi'rior fillet,
Hiilrrr Sclilfiff ndidii di' Ucil in/i'n'riir), and {'i) the lemniscus
medialis * (including the nuiin portion of the lemniscus, f the
^'fiiii
1
m
'i
m
'!!
-
\^
IFauptschleife.
\ HaupttJu'il (h'v Schh'.ifenschirht.
(188
THE NKuvors svstp:m.
superior fillet,* ccrtiiiii sciittci-fd biiiidics of the iiu'diul Iciiiiiis-
cus, f unci, linally, the iiiediiil accessory leimiiscus J) (Fig. 440).
^1 ■■ij ■
i
Fui. \U\. — Sclicniatic rciircscntiition of the ctmrsc of tlu> filiros met witli in tlie
ii-jiini (if tlic siiiicridr colliciiliis of tlic coriioni (|iiii(lriKt'iiiiiiii. ( After W. von
l'>c<'litfiiw. Die licitmiKslialmcn ini (icliiin inid Iviickcniniiik ; Dcutscli
von K. WcinluTK. II. And., l.iip/.., ISllit, S. 'JliT. KIk. ;>:5I. ' c/r, dccnssalio
Icfjnicnii vcntnilis (iMirclii; cif. dccnssiitio 1f>;nii'nti dorsiilis i Mcyncrti ' ;
((>'. a(|U<iln(tns ccrcUri ; _/'(•;(, coniniissiira poslcrior <cr(liii ; c/j. (di|ins pari-
biKcniiinnu I von iicclitcrcw ' ; ./'c. Jattral liundic of liasis ix'dnni iili : ft', medial
linndli' of liasis peduncnli ; fi\ fascicnlus retniflexns Me.vneiii ; ./'c, fascicu-
lus t<';;Mienti cenlralis < ci-iitinli- llnnhnihiilni ) ; J)), fascicnlus lonKitudinalis
niedialis; fcfis. stratum allium profundum (medullat<'d axones to dorsal de-
cussation ol' Meyiieit ' : /. lenniiscus medialis; /.v, liliie liundle iVoiii the
col lien I us iufi'rior to the I ha Iannis ; l/i. ceutrifnual Miiotoi' (ihres >{i'in>J fi'om
basis peduncnli to i'eKi<in of lemniscus, imihahly terminating farther spinal-
ward in the nuclei of origin of the nu)tor cerebral nerves (Spitzka's bundle,
iiti'itititi' (icfi's.sorisclif Sclilfiff of you Hecditerew ; Hiiiiili'l mm /''(i.v.s- -iir SclilciJ'i' of
tlu' (ierinansi; Isp. scattered bundles of the leinnis<'US i::iTslrfiiti' Svlilrlfcii-
hiiiiilrl of Von Hechterew ; riisxsriilcifi' nf Fle(disiK': »((, tractus opticus ; iii,
tnicleus lateralis superior of Klechsi;; (iiiirlfKx liiiinmiiKtfiisiA' von liechlerew) ;
ml III. dorsal part of ninleiis lurvi oculouiotorii : iiiii III. meclial part of
nucleus nervi oenloniotorii ; /», fasciculi pyrainidales ; ytcc. fasciculus iiednu-
culomannnillaris pars basilaris ipedunciilus corporis mammillaris i ; iir, nu-
cleus ruber; sii. substantia ninra ; ///. nervns oculoniotorius.
* 0/iere Srhlcife or riihnn de lieif supvrietir.
t Xi'i'-streute acce.sxori.'iclii' liiindcln dcr .Schleifentfchicht, von Ueehteruw ;
FnsHKrhlcife of Fleehsia;.
X Me<li(ilp.sa<r('Sf>iiri/<cli('.'< Bundel tier Schleife, voii Bechlerew, or coiillmi-
atioii of the Jiundd vum Fuss ziir Schleife.
GKOUIMNG AXI) ('IIAIX1N(} TOOKTIIKIi OF N'KUUON'HS. Cs;)
Of tliese variouH buiidk's wo may exclude from the gciK r;;!
oentripi'tiil path now hciiig considered (1) the hitenil lemniscus
wiiich is, in tiie main at li'ast, a (central acoustics (a'ntrii)ctal
]tath ; {'i) prol»al)ly apart, at least, of the scattered humllcs ;
and also (:{) the medial accessory li'iiiniscus which becomes
medullated at a later period than the rest of the lemniscus and
which, after solution of continuity, deffi-nerates downward, not
upward, and is thercl'ore to he rc^^Mrded as a centriru<,'al, proh-
ublya tnotor patli,and not as a centripetal or sensory path {ride
Chapter Fi-Xll). The old view of Meynert that the lemniscus
passed through the lateral part of the basis pedunculi was dis-
proved by Kleehsig, who showed that this area in tiie pes rep-
resented a ccrebro-cortico-frontal path which has nothing to do
with the lemniscus.
The medial lemniscus is made up largely, as we havi' seen
above, of the axones of neurones, the cell bodies of which are
situated in the nucleus funicidi gracilis and the nucleus funic-
uli cuneati (the nu-dial part of the latter, according to von
Monakow) of the o[)posite side of the nu'dulla ol)loiigata.
These nu'dullated axones we have traced as intenuil arcuate
Fl(i. IIT. 'rriiiisvcrsc si'dimi tliiiPiiKli mcdiilla <il)liiii;.';ita nf iii\v))(irii iliild at
level ((!' (li'ciissitio Iciiiiiiscoriiiii. Scries ii. seelioii No. 50. ) T.c. ratialis
ceiitr.ilis ; Dt'iJ., deeiissatici leiiiiiisciiniiii ; i'.ii.i.. filira' ai'cnatie inteniie ;
F.ii.c, (iliiie ai'cuata' externa'; F.<\. rascieiiliw cimealus liindaelii ; /•'.c. to
/•'.r., liiiiidles IViiiii raseiciilus ciiiieatiis tii runiialio reticularis : /•'. (•/.v., fascic-
ulus ccfehellospiuaiis oi' direct ccreliellar tract ; /•'.<;., fasciculus u'racilis
(lolli : F.r.j)., fasciculus ventralis iiriipriiis : Xii.ciini.. nucleus cniuiiiissuralis ;
Xn.f.c. luiclciis funiculi cuiieat i : Xn.f.ii.. nucleus funiculi jiracilis : /'//.. |>.vr;i-
luis: T.s.ii.W, tractns spinalis N. triijeinini; s.<i.. sulistaiilia fjelaliuesa [Uo-
landi]. I \Veij;ert-l'al pn paialion liy l>r. .Iiilin ilcwetson. )
fibres, which undergo decussation in tlie raphe (deoussatio lem-
niscorum, Fig. 447), then to turn forward to run through the
stratum interolivare lemnisci into the broad liat band situated.
li
\\
* r
1
I
I ill
OJto
'I'lIE NKUVl^rs SYSTK>r.
ill llic vontrul piirt of tlic pars dorsulis jjontis (l"'i<j. Hs). In tin*
upper part of the pons tho medial loiimiscus cuiiu's to occupy a
I'"i(i. tlH. Tr.iiisvciNc section tlirnuKli isthimis rhcinihi'iK-opliali of ncwlxirii
li:il)c. I Wci^icrt-I'al. scries ii. scctimi No. '^tiS. ) Hf.coiij., liiiicliimii con-
jiliictiviiiii ; C.i.. colliciillis iiil'evior; y. nucleus dcscrilieil liy Westpliiil as
lU'ol)al)l.v couceriied in tlie oii^'in of tlu' N. Iroclilearis ; F.I. in., fasciculus
lon^'itmlinalis niediaiis; /•'./'//., fasci-'uli louKitudinalcs [pyraniidalcs] ; /../.,
lemniscus lateralis; /,./«.. lemniscus medialis ; .V. /I'., dccussitio nervorum
tro( lileariiini ; .V. I'., X. trigeminus; Sii.l.L. nucleus lemnisci lateralis;
.\ii.r.l., nucleus ri'ticularis te^'inenti pontis ; /'.(/. I'., riiilix descendens [niescn-
ccpiialica] uervi trij,'eniiui. i Preparation liy Dr. .lolin llewclson. i
more lateral position (Fig. 449), and in the midbrain changes the
direction of its long diameter in cross section ; whereas in the
pons tlie long diameter of tlie lenmiscus is tninsverse, or latero-
mediiil in direction, in tlie niidl)riiin it is idmost vertical or dorso-
ventnd. The tninsition /rom the one form to the other takes
place by means of a graduid curve, very well shown by a recon-
struction made by Miss Florence Sabin. It is to be especitdly
ctn])liiisized tluit the terms meditil lemniscus and hitertd lem-
niscus hold for only a part of the course of these two bundles,
for while in the pons it is true that the lateral lemniscus is
situated nearer the surface of the metencephalon tlitin is the
medial lemniscus, still in the isthmus the lateral lemniscus
liil^
(illoriMNCJ AM) CFIAIXINO 'nHJKTHKIl OF NKURONES. 091
|i
T.l.p
Fa.i.
TXI.
Fio. 441».
Imumi
-Ho
l)iil)C.
izontiil si'ctiDii tlmuiKli tlie iiu'duUii. pons, and miiDniiin of ii new-
WtiKcrt-l'iil staiiiiiij;. Level of dorsiil part of corpus trapezoi-
delim and dorsiil portion of uueleus olivaris interior. iSeries iii, section No.
122. ) CI., corpus tniiie/.oideuni ; l>ic. ISi-.Cinij., decussatio luacliii conjunctivi ;
Dic.ltirlil., coininissure l»'t\veen He<litere\v's iniclei ; D.c.ii.r.. dorsal cii]isnk'
of nucleus rulier; F.a.i.. tilira' arcuata' interna' : I'asr. rctnif., fasciculus retro-
llexiis .Meynerti ; F.l.iii.. fasciculus lonnitudinalis niedialis; I'.l.j)., bundle
continuous with the fasciculus lateralis proprius of the cord ; F././i. <l<. dorsil
jiortion of bundle continuous with fasciculus l.itcralis proprius of the cord ;
f,.l.. lemniscus lateralis; I. .in., Icuiniscus nudialis; .V.///., radix N. oculo-
inotorii ; .\..Mi)t.\'., motor root of N. tri^jiniinus ; XT., sensory root of N.
trigeminus; .V. 17., radix N. aliduceiitis ; .V. 17/., radix N. facialis, pars .se-
cunda ; .V. ifst,, radix N. vestihuli ; .V. .\7.. radix N. accessiuii ; .V. .\7/., radix
\. hypoKlossi ; Sit.F.l.m., nuileus fasciculi lousiitudinalis medialis, or uu-
(deus commissura' posterioris 'iihin-r (hiiliiiiiiil<iriii.'<l.cni itl' Darkschewitscli ' ;
Xii.H.I I l.ni.. pars impar of nucleus N. oculonmtorii ; Xii.ii.III.L. pars lateralis
of nucleus N. oculomotoiii ; .V/i. ()..<,, ntudeus olivaris superior; A".».c. I'.,
nucleus N. cotdilea' venlralis; .V».(;./., nuideus olivaris inferior; Xu.o.n.m.,
luudeus olivaris access(uius medialis ; I'r.fr.iin.lK, tnu't from Deiters' nucleus
to tlie s])inal cord. Preparation hy Dr. .lolm llewetsou. I
\
^mm
■iy
'-
0l»2
TIIK NKUVOUS SVSTKM.
|)iisrti's iiicdiiilwiinl iiiid dtd'Siilwiinl, in order (o iiicrj^'c into tlio
iiit'ci'ior collicidiis of the- coi'iioiii (luadri^^ciiuiiii. At tiic siunc
liiiK- ti large portion of tlu' nii'dial k'nini.si'ns i>asse.s laterahvard
L.m
»l
7(i).
.1./.,
IV
in PS
Ml
Itlirs
al
IMirticiii iif
la
IMK
ni
• y
s ;
;. >
IK
•Irlis
) :
■'. 1
III
'lens
I'll
ties
III
the
]'ui. 150. — SuKittal scctiiiii of Italic's liiiiiii siiiirtly af'ttr liirtli (scrtii
iiii.Mi Iciiliciilai'is : C.i., caiisiila interna; /•'./*(/., liisciciili cc
|iyi'aniiiialt'S' : l..iit.. Iciiinisciis nictlialis tcrniiiiatiii;; in vcntr
tiialaniiis : Th.. Ilialaniiis; '/'.«., Iractiis ii|iti('iis; /, siilistaiit
ninlciis li.v|iiitlialaiiiiciis icorpiis Liiysi ) ; ■!. I'ciiirr miiliiui id' l,iiy;
arciiatiis lyrlnilciifiii'iniiicr Ki'iijicr of KIcclisit; anil viui Tscliiscli
Iciitiriii'iiiis : '.', rinpiis Kiiiiciilaliini niiilialf anil liiniatli it tlic
liiai'liiiini i|iiaili'i;.'('iiiiiiiini iiil'i riiis.
and dorsal ward toward the superior collieulns of the corijora
((iiadri^'eniiiiii, and aocordin<^lycomes to oocnpy a position as far
lateral as the lateral lemnisons. This portion of the medial lem-
niscus rininin<; toward the superior coUicnliis, and partly end inijf
ill its jrniy matter, is known as the superior lemniscus or fillet *
(o/irrr Sr/i/ri/r of Forel, rKhan tic Ufil si/prn'riir). The main
])orti()n of the lemniscus runs forward tmd somewhat lateral-
ward, heinji; hounded ventro-laterally hy the substantia ni<ira
and dorso-medially hy the red nucleus and the white fibres
which pass from its lateral surface into the hypothalamic
rcirion. The ventral })ortion of the superior fillet remains,
however, for a considerable distiince in direct contact with the
dorsal border of the main portion of the medial lemniscus.
* Willie tills is tlio description usually given of the superior loiimiseus. it
iniist lie pointed out that von Heehterew in his Leitunpsliuhnen (IHi)4). p. 113,
states that the (ili/^ir Sc/i/cifc of ]''or('l (iriKi'n from the nucleus collii'uli
iiiferioris. imd passes lieiieath the colliculus superior to becuine lost in the
[posterior part of the thalamus.
u
(IKOriMNO AND CIIAIN'INd T(K1KTIIK1{ OF NKlltoNKS. cii:',
Almvc tlic (IcciisMtitioii uf tilt' hnu'liiuiii (•otijuiictiviiiii, liowcvcr,
ill (lit' liypotliiilaiiiic rc^'iini u ('crtiiiii iiiiimiMt of ^m'iiv iiiiittir is
iiittTCiiliitcd Ix'twct'ii tlif upward (oiitiiiiiat ion of the superior Icin-
iiisciis and tiic upward coiitiiiiiatioii of tlir iiiaiii portion of the
Iciiiniscus, so lliat in coronal sections tiiroii.i:;li tiie liv[iotlialaiiiie
rejfion one sees two separate and distinct liundles, that nioreilor-
suUyund laterally plaecul forr((spondin<? to the superior leniiiiseiis,
wliile the lar^fer one more vent rally and medially placed cor-
responds to the main portion of the lemniscus. 'IMiis separa-
tion into two distinct Imndles in the lower hypothalaiiiie re-
V'ioii, however, is not to he made out in frontal planes a little
further forward. In these planes the tilires of the superior
lemniscus become inextrieahly mixed with those of the main
portion of the lemniscus, and for some little <listance farther
forward any attempt to separate the fibres belongiiifi to tlie two
bundles by jiurely anatomical means is entirely impossible.
The mixed Imndles turn somewhat lateralward and dor.salward,
and, breakin<f u{> into small fasciculi, become lost in the j^'ray
matter of the ventro-lateral portions of the tlialamus (accordinjj
to von Monakow, in the caudal portions of his ventral ^roup of
l'"i(i. l.")l. — S;i^'il!:il section tlirmiKJi iiiiitiini ol' (■cri'tiiiitii nf iliild slmrlly iil'irr
liirth (sctlidii Kisi. .1,/.. ;msii Iciiticiiliiris : C.i.. ciipsuln iiitcniii ; /■'./'//.,
I'iisciciili iiyniiniiliilcs in liiisis iiciliunMili ; I, .in.. Icnmiscns iiuMliiilis tcniii
iiiitini; in viiitnil nuclei ol' lliiiliuiin> : 7'//.. liiMliinnis ; T.n.. (nictns (i|iticns-.
/, Milisl;iiiti;i nifjra : ,'. nucleus liyinptiiiiliuuicns (ci)ri)Us Jjuysii; .^ nucleus
ientif'iii'iMis.
nnclei in the thalamus). In Fius. 4.')(), 4.")1 is shown a sai^ittal
section of the brain of a babe shortly after birth, illustrating
the relations h(>re under discussion.
Tf .
; !!:
05)4
TIIK NKIIVOUS SYSTEM.
Therp can be but little doubt tliat tlie lonniiscus considorcd
iu its wliolo leuj^tb from tlu' nuclei of the dorsal fuuieuli in tlu^
niedulhi obloiij^ata to the ventro-lateral region of tlie tlialauuis
iiu'ludes the axones of neurones, which are of very ditlerent
()ri<;in, and probably of ^jhysioloj^ical si<fniticance. Thus, there
is much evidence to show that not all of the axones going from
the niu'leus funiculi gracilis and nucleus funiculi cuneati into
the leiiniiseus pass as far forward as tlie thaliimiis. One large
series of fibres leaves the medial lemniscus just above the corpus
trapezoideum in order to terminate in the nucleus reticularis
tegmenti pontis of von Bcchterew. Many of them end in the
gray matter of the medulla itself, others in the gray ma ter of
the pons, still others in the gi'ay n<atter of the isthmus and of
the midbrain, and ilnally many of them terminate in the gray
matter of the hypothalamic ri'gion, short of the thalamus,
'rschernuik, by Marchi's method, has traced degenerated fibres
of the lemniscus to the vcnlro mviHitn, and Luys' body of the
same side, and to the globus pallidas of the opposite side. We
are thus justiticd in sj)eakiiig of bulbo-])ontal neurones, bul-
bo-mesencephalic neurones, bulbo-hypothalamic neurones, and
t he like. It seems to be true, however, that the nuijority of axones
passing from the nuclei of the dorsal funiculi in the medulla into
the lemniscuis reach the ventro-hiteral group of nuclei in the
thalamus before terminating. In transverse and horizontal sec-
tions through the brain-stem of the newborn babe, stiuned by
the Weigert-1'al method, I liave been struck by the very evident
masses of fibi'cs of tlu* lemniscus which enter into relation with
the substantia nigra. The method does not j)ermit one to say
whether these iibres ascend in the lemniscus to terminate in
the substantia nigra, or arise in the substantia nigra, and de-
scend in the lemniscus, though, (t jin'ori, the former of these
two possibilities seems the nnu'c ])robable. The bundles are so
definite (Figs, irri and 4-5:5) that .Miss Sabin has been able to
introduce them easily into her reconstruction of this region.
In addition to axones of different lengths arising froju the
cell l)odies situated in the nuclei of the dorsal funiculi of the
medulla, thei'c are contained in the lemniscus axones of lu'u-
rones liie cell bodies of which are situated in various gray
masses all the way from the medulla oblongata to the thalamus.
Thus, by Golgi's method and by the nu^thod of secondary dc-
generatio!! it has been shown that numy of the axoiu's of the
(iWori'INd ANIl CIIAIN'INd TOCKTIIHU (»F NKllfOXKS. ,J()5
Fk;. tr}'^. Traiisvf'vsc section tlmmjili nicscnccpliiildn of ncwlidrii hiitic I.cvil
(if folliciili Mi|icrii>i('s iif cDipdni (lUMdii^ciuiiin. (Wcim'it-I'al, scries ii, sec-
tion No. HIiS. ) .l(/.(7'C., a(|lleilllctiis cei-cliri ; /'cc. /.r.ro/i;., ileciissiitid liliicliii
edujiinetivi ; /)./., <l4'ciiss;itid le;,'nieiili venlnilis [rciilriitc lliiithniknir.Kini u\'
Fore!) ; I'.l.iii., rasciculus Idti^iliiiliiialis iiieilialis ; F.l'ji.. t'asciciili |iyranii(laies
ill tile pars liasilaris pout is: /,./»., leiMiiisciis media I is : .V. / I'., N. troclilearis ;
.Vh./.s'., inicleiis lateralis superior ol' l''leclisit; ; .Vh.ii./I'.. liiK'leiis N. trocli-
learis; Sl.iilli.j)., stratum allium ])rorun<lum ; SLiji-.r., stratum Kriseum ceii-
tnile; S.ti., sulistaulia iiit;ra. i I'rcparatioii liy Dr. .loliii llewelsoii. )
it seoms probiiblc that iixoiics pass tlirougli tlu> loiiiniscus t(»
the region of the tliahinms. Tlie niodiiil leiimiscus is, there-
fore, a very cojn])lex tract, consisting of fibres of diifereiit
length, of (lilTerent origiti, and of dilTcrent termintitioti. It i ^
thus not dissiniihir in (••-Mstitution from iiiiiny other traets
whicli have been Wtll st ' — for exanii)le, certain fasciculi of
the cord, tlie fiisciciilus .igitudintilis modiiilis of the rhondi-
<'nce])halon, iind tlie like.
'I'here has been for ;i long time much disjuile ;is to the rcla-
w
i!f
:r\i-
■ V
w
'U^
i'-V
'
W^
It'iv^.i
i:
i. :
('.'.)(!
THE NKllVOL'S SVSTEiM.
Ku. ruber.
L m.
-N.vm ^"'^
Fi(t. ■(.");!. — Il(iri/iiiit:il section tliroiifili tlic mcdiillii, |imis. ;mtl iiiidljiMin ol" iicw-
liorii bal
I,<vi'l iil'strMtmn iiitcnilivarc- Iciimisii. cipi-piis Iraiiczoidcmii mihI
nucleus rulier. \\'ei^ert-l';il st;iininu.
Ni-ies MI. set
tic.n No. i;i(i.
c.t.
pus tn
(lelllM ; /'('(■. Ill\( 'i
'"./■
ilecussMtio In'Mcliii conjunctivi : I). I., decii:
.;itio lejjnienli Vent nil is ( ventral I e"nienl;il (leciissiil ion of I'"oi'er; /•'.
Un:t. ),
tiUni' avcu:il:e iiit( riiie (ilecnssalio lenmiscoi inn )
/■'./.. nines conliniKni- with
tlie I'Miiiciiliis lateralis of the spinal •■(n'll : FJ.iii.. fasciciilils lonj;ilU(lini
Ills
ineillalls
X.lll.. radix N'.
I'.f.M., fasciculus relrollexiis Meynerli ; /..
leiniiisciis ini'diali
inloiniitorii : .V. Mnl. I'
niotiu' root o
I' N. triireiiiinn*
A'.Sk. r., sensory root of N. Ii
linns: .V. 17//. (coc/i. '. radi.x \.
.V. 17//.
at. I, radix N. vestiliiili ; .V. 17., radix N. alidncentis ; .V. 17/., radi>
N. facialis, jiars seciimla ; X.X'IL. radix N. li.vpojilossi ; .\ii.t'.l.ni., iiiieleiis
fasciculi loimiludiualis niedialis. or iiuc'-ns coininissiiiie jiosterioris ( i/'x ci /■
OcnliiiiKitd
(iriKihifii o
f DarUscliiwit
sell)
.///.. tiiKleiis N. oculoinolinii
Xii.o.ii.m., nucleus olivaris a<cessoriiis niedialis:
ferior; .V».()..v.. nucleus olivaris superior: .\ii.
.\
II. O.I., nucleus olivaris in-
riilii'
Ills rnlier: si.i.l.
stratum iuterolivare
.lolm llewetson. '
siilistantia niura. > 1 'reparation liy Dr
GUOUIMXO AND CIlAINIXd TOCKTIIEll OF NKUIIOXES. (;<)'
tioiis of the iiuhIuiI lemniscus to the cerelmil eortex. Two
luaiii views may be said to have been doniinaut. According to
the one, formerly championed in the main by Flech.sig and
Iloesel, a hirge majority of the axones making up the leninis-
cus in its course through the rhombeiu-ephalon pass without
interruption through the internal capsule aiul out through the
eoi\)na radiata to the cerebral cortex. According to the other
view, supported by Mahaim, von Monakow, and others, very
few, if any, of the fibres of the lenniiscus pass directly without
interruption to the cerebral cortex. According to the latter
o))servers, the majority, if not all, of the fibres of the lemniscus
termiiuite in the interbrain, chietly in the optic thalamus, the
connection with tlie cerebral cortex being made by means
of neunnu'S of a higlier order. Inasmuch as an accurate
knowledge of the exa(it relations existing here is of fnmlamen-
tal importance, it seems desiral)le to consider briefly the history
of these two views (Fig. 454) and the evidence thus far brought
forward in favor of each.
Before entering into this discussion, however, it will be well
to clear the way by (h'fining the term " cortical lemniscus "
{Uindcnschli'ife of the Germans, ritb<ni de Ji'fil corfiral of the
Belgians and French). This term was introduced by von
Monakow in ISS-f us the result of ex])eriments made by von
(ludden and himself. \'on (iudden * showed that remo\..l of
the cerebral hemisphere in the rabbit by his method was fol-
lowed by atrophy of the h-mniscus f as far down as the corpus
trapezoideum. ^'on Monakow J fouiul that removal of a por-
tion of the parietal lobe in the cat, corresponding to the "zone
F " of Munk, led to marked atrophy of the lemniscus, which
extended not only as far as the corpus trapezoideum, but also
through the interolivary layer and internal arcuate fibres of the
op])osite side to the nuclei of the dorsal funiculi in the medulla
oblongata. lie could make out, after a long time, not only
atrophy of the fibres of the lemniscus, but also degeneration of
* voii GiKldeii, B. Beitra}^ zur kenntniss des Corpus nianiniilliin* uiul
(liT sDjiciiiiniilcii Schenkcl dps Fornix. Arch. f. Psychiat. u. Ncrvcnkr.,
B.M'L. M. xi{\HHl). S. 42S-4r)2.
t Koichcrt's Srhleifp.
\ von MiHiakow, (". Fxpi'rimiMitcllc HcitWiire zur Konntniss der Pyra-
niidon- nnd Schloit'enbulin. Cor.-Ml. f. sehwuii;. Aerzlc, Busol, Mil. xiv(1884),
.S. 1:2<.I; l,-,7.
46
w
m
1U5
-!i
|»p|
1 t
:M ij
Hill
098
THE NERVOUS SYSTEM.
the ganglion cells of the nucleus funiculi gracilis and of the
medial i)art of the nucli'us funicudi cuneati of the opposite side.
Ina8mn(!h as the welfare of a large portion of the lemniscus is
obviously dependent, as these experiments showed, upon the
iiitegrity of the cerebral cortex, von Monakow introduced as a
designation for that part of the lemniscus which degenerated
FlO. 454.— Two schemes illustritiiiR the two main views eoiieerniiif; tht> <'ourse
iiiui iiit»M-ni|)ti((ii of the jteiieiiil sensory l>atii ' lemiiiseus medialisi. i After A.
van (lehiieliten. Anatomic du systeme ncrvciix (!<• I'iionimc, Louv., lS!t7, \>.
7H'J. l''i)is. 544, 5t5. i A, sdienie illust rating the view tiiat tiie lemniscus runs
out directly to tiie cortex without int<'rru|)tion in the thaiannis. H, scheme
illustriitinn the view tlial the h'niniscus is connecl<'(l witli the cortex indi-
rectly, being iuterrupted in the thalaunis.
on removal of the cortex the term " cortical lemniscus " ( liiudeti-
schh'ifc). The term Rindcnxchleifc has l»een used in ti very
different sense by other investigators, but it seems better to
limit its use to the signilicance attached to it by von Montikow.
%->.
GltOUl'INC} AND ClIAININC} TCXJETIIEH OP NEUHONKS, (59<)
A little eiirlior Spitzkii * had described a case in which,
following haemorrhage in the region of the lemniscus inside the
pons, there had resulted degeneration of the fibne arcuati« in-
terna} and of the nuclei of the dorsal funiculi on the opposite
side of the medulla oblongata.
The view of Kleclisig f and lloesel and those who adhere to
the same opinion dates from Flechsig's study of myelinization
in 1881, but is based mainly upon the study of a case by lloesel
in Flechsig's laboratory, | In this case, following an old defect
(porencephaly) of the left cerebral hemisphere involving prin-
cipally the posterior central gyrus, there had resulted secondary
disease of the main portion of the medial lemniscus, which ex-
tended all the way to the niudei of the dorsal funiculi in the
medulla, lloesel concluded that nine tenths of this portion
of the lemniscus was " cortical lemniscus," and that not only
was this true, but that the fibres passed directly all the way
from the medulla, through the pons, midbrain, and tegmen-
tum, to enter the internal capsule and to pass through it
and the corona radiata without interruption anywhere to the
cortex of the posterior central gyrus. If this view were correct,
two neurones woidd suffice for the conduction of sensory im-
pulses from the surface of the body to the cerebral cortex, one
corresponding to the spinal ganglion cell, the other bulbo-
cortical (that is, myelencephalo-pallial).
Forcible objections to the doctrine of Flechsig and lloesel
was offered in 18!)6 by Mahaim.* This investigator, working in
* Cf. Spitzka, E. C. A Contribution to the Morbid Anatomy iitid Syinp-
tdiniitology of Pons Lesions. Am. J. Neurol, and Fsychiut., X. Y., vu\. ii
(1H88), pp. 017-661.
■f Fleehsiji^. P. Zur Anatomic und Entwiekelungsgescihiohte di-r I.ci-
tungsbahnon im (Jrosshirn des Menschen. Arch. f. Anat. u. Physiol., Anat.
Abth.. Leipz. (1881), S. 12-75.
X Flechsig, P., iind (). lloesel. Die Centralwindungen, ein Centralorgan
d(T Hinterstrilnge. Neurol. Ceiitralbl., Leipz., Hd. ix (18i)()), S. 417-41!».—
lloesel. 0. Die Centralwindungen ein Centralorgan der llinterslninge und
des Trigeminus. Arch. f. Psychiat., Herl., lid. xxiv (18i»2), S. 4r)2-4!)().—
Kin weiterer Beitrag zur Lehre vom Verlauf der Kindensehleife und cen-
traler Trigcmiinisfasern beim Menschen. Arch. f. Psyjhiat., Herl., Bd. xxv
(!S!«),S. 1-17.
* Mahaim, A. Ein Fall von seeundiirer Krkrankung des Thalamus o[iti-
eus inid der Uegio subtiuilaniica. Arch. f. Psychint. u. Nerveiikr., l>erl.,
Bd. xxv (189a), S. 34y.
11
9>,' :
s 'I
I
III;;
i
L
}\
\
u
I
700
THE NKUVors SYSTEM.
von Motiakow's lalxtriitorv, studied most oarcfidly a caso of pri-
niury dofcct of tho ctM't'hral lu'tiiispluTc wliii-li involvi'd tlio
white matter of both (-entral ^yri. Tlie lemniscus was second-
urily diseased. 'I'he ehaufz^o in the lemniscus, however, was not
that of typical secondary def^eneration, but rather of simple
atroj)hy (dimiiiution of the calibre of the individual tibres).
'I'he whole intei'ual ca]»sule was, however, transformed into com-
pletely degenerated tissue. Mahaim, then, having found that
the fibres of the lemniscus ended free in the degenerated tissue,
argued that it was improl)able that the same set of medullated
tibres should in one })art of their course (in the lemniscus) show
simple atrophy and in another ])art (internal capsule) tyjjical
secondary degeneration. He came, therefore, to the coticlusion
that the tibres of the lemniscus do not pass directly out to the
cortex, but that they are interrupted in t le region of the thala-
mus, thus contirming a view previously arrived at by von J\lona-
kow. .Mahaim does not deny absolutely the existence of any
direct fibres from the lemniscus to the cerebral cortex, but as-
serts that if siu'h tibres exist they can be but few in number.*
A very important contribution to our knowledge of this
whole subject has l)een made by von Monakow f in an article in
which he sums up all of his wide experience with secon(hiry de-
generations in human beings, and compares the results of these
with those of the ex|)eriments which he has nuule upon ani-
mals. These are so important that they must be brielly re-
viewed here. Von .Monakow finds that when the whole cere-
bral hemisphere of the cat or dog is extirpated without injury
to the thalamus, the lemniscus uiulergoes a reduction in volunu'
of as much as one third, a reduction which is due not to actual
degeneration of its constituent tibres, but to simple atrophy.J
* 'I'lic (liictriiio iulviiiK'Oil liy I'^lpclisij; and von nccliturow. of n inirticiim-
tion of liln-L's of tlie liMiiiiiscus in tlic fonnatioii uf tlie ansa Icnticiilaris, thus
connecting with Lays' body and tlic hMiticnhn- nucleus of the sanio si(h'. is
stroni^ly opjiosi'd t)y voii ^lonakow imd Mahaim ni, the pvouml that the evi-
dence from tlie study of sccoinhiry degenerations negatives it.
f von ]Monako\v, C. l''x])erimentelh' nnd ])ath()h)gisch-anatoiMisclie Un-
tersuehuiigen ueher die Haul)enregi()n den Sehiiiigel nnd die Regio sul)-
tlialainica. nelist Beilriigeii /ur I\ennlniss friili er\vorl)eiier dross- und Klein-
liirndefecte. Arch. f. I'sychial. u. N'ervenkr.. Herl.. Rd. xxvii (18!)5), S. 1.
\ von Momikow iloes not atisolntidy cxcIikK' the total al)S(ir|)tion of single
filires, but maintains that if actual secundary degeneration occurs at all it
is minimal in amount.
(iKC»L'J'lN(J AND CHAINING TCKiETIIHIl OF NKUliONES. 7(»1
' this
L-lo ill
H'SO
;ini-
re-
•rre-
jury
unu'
CtUill
Un-
p sub-
iKicin-
1.
sii
all il
Tlu' aiiioiint <»f cliiiiifrc in tiio Iciimisiiis after removal of tlie
lieinisplu'i'o decreases, jiari yw.v.s», as one examines frontal sec-
tions successively from the upper to the lower parts of tlio
lemniscus. Kveii in cases in which after cortical disease tliere
is comi)lete secondary def^encration of the internal capsule, the
area occupied hy the lemniscus in the hypothalamic rej^non just
ventral ami lateral to tiie lateral portion of the white matter
forming the capsule of the red nucli-us shows no dej^eiieriitiou,
hut simple atro])liy.
If the lemniscus he cut t]irou>,di in tlie rejjrion of the ])ons
the d(
th
lie cat at hii'th, very inti'use secondary deji'en-
eration in an ascending direction results, hut the degeiu-rated
tlhres do not extend as far upward as tlu' internal capsule, nor
do any of them enter the white matter of the hemisphere (von
Monakow). The degenerated tlhres can he followed, however,
to the thalamus, and a distini't loss of tine tlhres in the ground
suhstance in the ventral nucU'i of tlie tludamus can he nuule
out. Von Momikow states that a degeneration of the lemniscus
in an ascending direction lias thus far not been ccrtaiidy followed
beyond the region of the ventral group of nuclei in the thala-
mus.* Mott's experiments in this connection arc especially con-
vincing. In five cases of excision of the nuclei funiculi gracilis
et cuneati in monkeys he could follow the degeneration as far
upward as the hypothalamic region, but no fartlier.
I must agree, therefore, with Mahaim and von Monakow,
that, ///. f/ir tiKfin path at aiiij rati\ between the nuclei of the
dorsal funiculi of the medulla oldongata and the cerel)ral cortex
at least two neurones are superim])ose(l, the th"st with a cell
body situati'd in the nucleus funiculi gracilis or in tlu' nucleus
funiculi cuneati, its axone extending cerebrahvard as far as
the ventral portion of the thalamus {Siistcnia tciHin'sratr iiij/r-
l('iirri)/ial<HfifiHr/i/ialicaiii),nui] the second with a cell body situ-
ated in the ventral region of the thalamus, its axone passing
through the internal capsule and corona radiata to the cortex
{Si/st('iti(i ncannitcain dicnfcplKdo-jiallialani). The meduUated
axones from the cell bodies in the thalamus in the region in
which the U'mniscus terminates, at least those which run out to
the region of the central gyri, ooctipy that jxtrtiou of the in-
* Sincp tliis statomi'iit was made tlu' ri'isuarch (if Tsi'licriuak has bi'i'ii
piiltlislioil, (•/(/(' infra.
*
r'
,1
l! I
4v;-
l.
ro2
TIIK NKUVOUS SYSTEM.
tonial oapanlo wliieli corrcspoiuls in froiitiil sections to the
first ciiudiil pliiiu's of Luys' body (von Monukow).
TscluTMiiik * ims recently restudied the original brain do-
scribed by Klechsif^ and Iloesel. The defect, wiiicli had lasted
for fifty years, involved tlie gyrus centralis posterior down as
far as the island j.iid that part of the lobulus })aracentruli8
which lies between the paracentral sulcus and the fissura col-
lateralis. it extended also into the gyrus centralis anterior
and the lobulus parietalis superior, but involved the white
matter of these gyri oidy slightly in their upper portions.f
Following upon the destruction of the cortex there was disa{)-
pearance of the corresponding portions of the corona radiata,
and farther down disappearance also of some of the fibre
bundles whicdi partly run over the dorsal coriu-r of the puta-
nieii, partly cut through the '"ridge regioTi " of this mass of
gray matter, tlividing it up into wedge-shaped areas. 2s'o alterur
tion could be found in the substantia grisea of the nucleus
lentiformis, or of the nucleus caudatus. At the level of tiie
ridge of the putamen (in its caudal part) the degenerated area
divides into two jjortions, which assume the form of bands.
One of these passes through the capsula interna iji a transverse
direction, breaks through the zona reticularis ( Tli<tlavmss(hale
or <iitti'rsrhlclit)y and extends into the vetitral half of the nu-
cleus lateralis thalatni. The other band of degeneration sinks
ventral from the former to ])ass along the dorsal surface of the
nucleus lentiformis ; byway of the capsula interjui the latter
band passes into the basis pedunculi (Fig. 455). While in the
u])per ])art tlu'se diverging bands of the degenerated area both
])ass through the pars occipitalis capsular interna', they do not,
however, extend between the same frontal planes, but the band
descending into the basis pedunculi conu>s to lie frontalward
from that passing transversely into the thalamus. In the basis
pedunculi the former band is no longer recognizable as a dis-
tinctly separate area, but the loss of fibres is mainfest in a dif-
fuse reduction of the total nuiss of the basis pedunculi. In
connection with this the fasciculi longitudijuiles [pyramidales]
* Tschermak, A. Ueber den cpntriilon Verluiif der luifstoigeiidon Ilin-
tcrstrnngbalincn nnd dercn TJozioliim^^cii zu don Riihiion iiii Vordorseiteu-
slriuis. Arch. f. Aimt. ii. Physiol.. Anal. Al)th., Loip/. (18!)S), S. 291-400.
\ von Monakow, in his oriticisni, had assnniod that a inncli larger amount
of the white matter of the lobus parietalis had been involved.
OROUIMNG AND CHAINING TOUKTHEK OF NKLUUNKS.
ro3
of the sanio side are rerluced in size as far down as the deeus-
satio pyraniidum. Tscherinak states that from the h-vel of the
(U'(Uissatioii downward into the spinal cord tlie fasciculus cere-
hro-spinalis ventralis is ahsent on the side of tlie lesion, while
the contra-lateral fas(;ieulus eerehro-spinalis lateralis is only one
fourth its normal size.
The atrophic process in the thalamus, as studied hy Tsclier-
nuik, is of especial interest in connection with the dis(Mission
above referred to. Iloesel in his first communication had ex-
Fl(i. IM. — Sclicnic of the hiiiids of (IcKt'iicratiDii in the case of IIocscl and Flcch-
sifi. coiistriictcd on tlic basis of a section inclined from al)ove and forward in
a direction downward and backward throii^ili a normal liuman brain. (After
A. Tsciiermak, Arch. f. Auat. ti. I'liy.siol.. Anat. Abtb., I.eipz.. ls!)S, S. 312,
Kif,'. 1.)
Hin-
loiteii-
kiiiunt
pressed the opinion that the atrophied fihres simply passed
throutjh the thalamus into the re<jion of the tc<imental radia-
tions of the red mudeus, and fartiier on into the curved area of
the lemniscus medialis as well as into the contra-hiteral hriichiuni
conjunctivum. lie noticed that the nuclei in the thalamus
were diminished in size, hut believed that this was due essen-
tially to loss of medullated fihres, the cells remaining u!ialtered.
In a later report (1S!I:5) he admitted a moderate loss of nerve
cells in the thalamus. Still later, Flechsig* described total loss
* FlcK-lisij;, P. Dio Tjocalization der gcistigen Vorpingo, etc. Ijcipz.
<18fl6).
(I
I I
H
\ ;.
1(4
THE NERVOUS SYSTEM.
n
t i
;
;
i
I
i 7 f '■
IIP
i ■
I
f
1
of tlic nerve cells in the jiucIcih iircuiitua tlmlami (srlnih'ii-
fi">riiii;irr A'Ur/wr) iind in the ventrul part of the nueleus luter-
iilis tliulanii, tliat rej^ion of the thalatmis whence are derivetl
the medulhited axonen of Fleehsij^'s fcetal sensory system No. I
{I'ide Chapter LI) which pass to the central f^yri. Tseherniak
confirms Klechsijj^'s tin(lin<{s, and states, in o])positi()M to
lloesel's reports, tiiat along with loss of the fibres hi'tweeii
the centre iiiedian and the fn/m/oifonnif/er Kor/nr, as well
as the fibres between the .srhaleiifoftiiiyer Korjirr and the
"ventral nuelens in the narrower sense," there has actually
been a great loss of ganglion cells in the sr/i(i/nifoniiif/cr
Korprr on the side of the lesion. Further, the ventral ])art
of the nucleus lateralis thalami is nuirkedly atroj)hic, and
great numbers of nerve cells have been destroyed in this
region, especially in the ventral half of the occipital third
of the nucleus lateralis thalami. In addition there was loss
of cells in the lateral part of the retilre niediau. No altera-
tion could be found, however, in the dorsal part of the ansa
lenticularis {Fcid 11., of Forel, which Flechsig thinks repre-
sents a connection of the cerebellum, especially of the nucleus
dentatus witii the nucleus lentiformis) nor in the nucleus
hypothalamicns.
As Tschernuik emphasizes, the demonstration of the disap-
pearance of such a large number of cells in the ventro-lateral
group of nu(!lei of the thalamus lends to lloesel's case a new
significance ami a new interest.
lloesers case proved the existence of a connection between
the nucleus funiculi gracilis and the pars medialis of the nu-
cleus funiculi cuneati of one side with the ventro-lateral group
of nuclei of the thalamus and the central gyri (especially the
posterior central gyrus) of the opposite side. Though lloesel
did not recognize the interruption of this connection in the
thalamus, the bringing of the proof of the termination of this
sensory nunhirtion jhiHi in the central gyri — that is, more or less
in the region which correspoiuls to the place of origin of
the medulhited axones of the centrifugal fasciculi cerebro-
spinales — was an advance, the importance of which it is diffi-
cult to overestimate. That the rondurfion path hetween the
medulla and the cortex consists in the main of at least two
sets of superimposed neurone tii/fitentu is clear from the later
investigations.
I a
(JltOUl'INU AND fllAlNLNO TOOKTIIKIi OK NKl UoNKS. 705
liiolsoliowsky * 1ms studied the brains of two of (lolt
/ s
dof,'s, oiu' almost two and a half years after removal of ono
cerebral hemisphere the otiier about niiu' mouths after removal
of one hemisphere and two mouths after removal of the oppo-
site hemisphere. In the first dog the corpus striatum on one
side was also renu)ved ; in the seeoiul do;^ both corpora striata
were extirpated, while the optic thalamus remained uninjured
in both animals. Hielschowsky found secondary atrophy in the
optic thalamus but 110 degeneration in the lemniscus, and there-
fore eoncdudes that the fibres of the lenmiscuia do not extend
beyond the thalamus, and that they can influence the cortex-
only through the intervention of neuroiu'S of a higher order.
Very important confirmatory work in this connection has
lieen done by Jakob f and by the Dejerines.J The latter inves-
tigators have made sections of niiu'teen hemispheres, in which
there were cortical lesions without involvement of the basal
ganglia. The cortical lesion was more or less extensive, but in
all these nineteen instances it involved the Kolandie region
and the parietal lobe. In no onc^ of the cases was the medial
lemniscus degenerated. In three very old eases there was a
slight diminution in the volume of the lemniscus, but this was
due to simple atrophy aiul a diminution in calibri^ of the indi-
vidual fibres, not to a decrease in the number of the fibres. In
all nineteen eases there was intense secondary atrophy of the
optic thalamus. They insist, therefore, that the path from
the nuclei of (ioU and liurdach in the medulla to the cerebral
cortex consists of at least two neurones — (1) an inferior or
bulbo-thalaniic neurone correspojuling to the medial lemniscus,
and {'i) a superior or cerebral neurone connecting the tluila-
nius with the cerebral cortex. Von Hecditerew's elaborate scheme
of the central paths is reproduced in Fig. 4r)(i.
The view advanced by Flechsig and liecditerew, according
to which the lemniscus forms connections with the nucleus
hypothalaniicus of Luys and the globus pallidus by means of
* Bielschowsky, M. Obcre Schloifc mid Iliriin'ndc. Xinii'ol. Cfiitrallil.,
Leii)Z., vol. xiv (180.")), S. 2()r)-2()7.
f Jakob, C. Kill Roitnig zur Lohre voii Sclileil'cnvorlauf (obei'c, liiiulon-
Thiilaimisschloifc). NVurol. ('oiitriillil.. Lcipz.. vol. xiv (IS!),")), S. ;{(iS-:!in.
\ I)(!Jeriiio, .T., ct Mmc. .1. Dojcrino. Sin- les I'oniu'xions (hi rulian do
Roil iivw la cDrticalite t-i'ri'brale. ('ompt. rciid. Soc di> liiul.. Par., 10. s„ t.
ii (18!»r>), pp. -^HS-a'Jl.
IMAGE EVALUATION
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706
THE NERVOUS SYSTEM.
Fio. 45fi.
I|
FlO. 456. — fontral pat lis as at present uiKlerstood with reference to tlie five ein-
brydiiie sllliilivisiniis nt" the hraiii. (Scheme coiislnictid 1>,V K. von Weinberg ;
taken from tlie chapter written liy \V. von Hechterew, in A. Kaiil)er's text-
hook. ) /''('.'j/v.s — /, fascicniMs fjracilis (ioili ; J. fascicniiis cnneatns Hiirdaelii ;
2'". lili.es from tlie nn( leusfuiiieiili eiineati totlieeerehellum; ..',fasci<Miinscere-
helhi-spinalis or direct cerehellar tract of FU'chsis; ; ,(. fasciculi cerel)rospinales
(pynimidales) ; .'/ , f.iseiciilas eerel>ro-spiiialis ventralis ; '>, fasciculus lateralis
nu'dialis; 'i, fasciculus ventro-lateralis (iow<'rsi; 7, lihres from fasciculus
lateralis which ascend on tlie later.il surface of the medulla ohloUKala ; N,
fasciculus lateralis et ventralis proprius iiassiiiK into the formatio reticularis ;
S' . tnu't from the nucleus N. vestihuli lateralis ( Deifers) to the fasciculus
later.ilis i)roi)rius ; ,'/, fascicuhis ventralis jiroprius ;.''', .''", fihres from the
fasciculus ventralis proprius to the nucleus reticularis te^imcnti and tins
nucleus centralis superior ; .''"', fihres of the fasciculus loiiKitudinalis medialis
contiinnius with the fasciculus ventralis i)roprius ; UK fihres of the lemniscus
niediali^ arisinj; from the nucleus funiculi gracilis; /'/.scattered bundles
of the main portion of the lemniscus (I'mm the nuclei terminales of tho
cerebral sensory nerves?); Ul" . librcs from the lenniiscus medialis to the
nucleus reticularis t<'};uienti ; //, lihres from the nucleus funiculi gracilis to
the cerebellum ; l.i. lihres of the main ]iorlion of the medial lemniscus
arisiiif; from the nucleus funiculi cuneati ; /.>', /.;". films of the lemniscus
nieilialis to the collicnius superior and to the nucleus hyiiothalamicus i corpus
Luysi ) ; IJf. tibres from the nucleus funiculi cuneati to the nucleus ceutnilis
inferior (throiifih the i)osterior decussation); I-',, fibres contu'ctinj.; the
nucleus hypothalaniicns with the kIoIius pallidus ; /6'. fihres from the tilobus
l)allidus to the cerebral cortex ; IS. lihres of the corpus tra))ezoideuni which
go from the nucleus N. cochlciP vcritnilis to the nucleus olivaris sn|ierior and
to the lemniscus lateralis; lU. fibres of the lemniscus lateralis; _'". lihres
from the nucleus olivaris superior to the nucleus \. ahducentis; :il, fihres
connecting; the inicleus fast ij;ii with the nucleus olivaris superior; ,^.', fibres
connecting the ccllicnlus inferior with the nucleus reticularis te};nu'nti ; ..'.?,
fihres from the region of the thalanms to the formatio reticularis; .'J. fibres
from the pons through the raphe to the formatio reticularis and to the
nucleus reticularis tcKuienti ; .'■;, fasciculus ]iedunci!lo-maminillaris jiars
tcKUicntalis [lliniheiihiinilcl. von (tudden); J'l' . fasciculus pedunculo-mani-
millaris pars hasilaris (pedunculus corjioris mamniillaris' ; JH. accessory
bundles of the lemniscus; .W', liluvs connectinj; the substantia ni);ra with
the cerebral cortex; ,.'T, fasciculus retroflexns (Meynerti); ;,'N, fibres from
the nucleus colliculi inferi<pris to the thalanms iso-calleil OlicifsvUlvifr,
according to von Hechterew); .'.'', br;ichinm (piadrifiemiinim inferius; ..•'.'/,
fihres from the corpus ijeniculalum mediate to the cortex of the temporal
lobe ; .il>, fihres couuectinj; the colliculus superior with the corpus t;enic-
ulatum laterale ; .;/ , tibres of the commi.ssura posterior cerehri (dorsiiland
ventral portion i ; ..''", tihresfVom the corpus piiu'ale to the nucleus haheuulie ;
S2, fasci< ulus thalamo-mammillaris ' N'icq d'.\/,yri ) ; .;.', lihrts counectinf; the.
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llialaiiHis with tlic uiiilciis Iciitit'oriiiis ; S.',. filircs from tlic iinclii Ijitcnilcsto
the (•crclii'llmii : ..'■;. I'ascicilliis centralis IcKiiiciiti (ciidi-ulf Ilniihi'iiliitliti) \ Sd,
iibrcs (•((iiiu'clinn (lie niiclciis iilivaris iiifciidr with llic (■crihcUiiiii ; .;,", Iil)rcs
ctiiiiicctiiifj the iMulclis <l(iitatiis with tiic coitcx of th^ ccn liclhmi : *s',
,s|iiiial Uiiiiiih' III' the lii'ai'hiiiMi ]>iiiitis; .;.''. ]iart of linii'liiuin ('(iiijiiiictiviiiii ;
.'l<). cfi'chi-ai hiiiidh' of hrachiLiiii pcnitis; .(/. tihics fmiii tlic liiichils N. vcstih-
tili su|pcriiii' (villi I'cchtcicw I anil fioiii the hiicKmis N. vcstihiili hitcralis
( Dcitcrsi to tlic ccichcliiiiii ; J.', jiart of the l)rachiiiiii coiijiiiictiviiiii : )•>'..(.{,
lilifcs coliuectiiit; the central nuclei of the ccrehcllmii with the cei-cbclhir
cortex: -I'l. part of the lirachiiiiii conjiinctivniii ; J'/'. IiuimIIc foriiiiiij; a coni-
liiissiire hctweeii Ucchterew's nuclei of the two sides anil lyiiij; Just ventnil
to the hrachiuni conjiiiiclivmn ; ,(,', .(N. lihics from the nucleus nilier to the
luicleus leiitiformis, the thalamus, anil the ceiehral cortex ; ,(.'/, lihrrs con-
necting the cor|ius striatum with the filohus palliilus: 'i(l.',ii\ lilin- of tlie
iiU'dial i>ortion of the basis iieduncnli coniiectiii;; the lobus frontalis and the
forpiis striatum with the nuclei ]ioiitis: ')J. fibres from the thalamus to the
cerebral cortex ; v;, Iibrcs from the colliciiliis siiiierior and the corims '(cnic-
lllatum latcrale to the lobiis occipitalis: .7,", fibres of the fornix; .'iS, radix
lateralis liactus optici : .■;.'/. radix niedialis tnictns opfici ; <lii, fibres from radix
lateralis Iractns optici to the thalamus : til, fibres fro' sinie root to colliculus
superior: <i.J. fibres from same root to the corpus f;(iiiculatnm ; ti.i, ;ibres
from the tractiis oiiticns to the uray matter aiioiit the venlriculns tertiiis;
»;',J, direct liemis]diiiic bniidle of the oi)tic tract i von (iuddeii); ti'i, fibres
from the medial rm t of the optic tnict to the li iclens leiitiformis ; CC, fibres
from the medial not of the optic tract to the colliriilus inferior: 6',\ fibres
folincctiii}; the col pus sf rial:iiii with the cerebral covtex. (inii/ Mdsnrx — /,
nucleus funiculi ■rmcilis : -■'.nucleus fnnicnli cuncati;..'. niicleus lateralis
veutralis: ///, iincli us X. ocnlomotorii : ,J, iincleiis lateralis ilorsalis; /I',
nucleus N. trixdilcaris ; f), nucleus fnnicnli veutralis: ')', niiclcus olivaris
inferior; 17. uiKdeiis N'. abdnceiitis; 7. niicleiis centralis inferior: 7. nucleus
N. facialis; S, nucleus olivaris siijierior ; ,s . nucleus N. veslibuli lateralis
Deitersi; S", nucleus X. cochlcie veutralis; ,v'". other acoustic nuclei : /,V,
nucleus fermiiialis X. ftlossopharynjrci ; .''. iinclei pontis; /'/. nucleus reticu-
laris tej,'iiienti ; //. nucleus lemnisci lateralis: /.■', nucleus colliculi iiiferioris ;
IJ', colliculus superior • /■>. naiifilioii inter]ieiliiiiculare ; /.(. nucleus centralis
suiierior ; /.7, Hecliterew's coriais |iarabi<;emiiium : /'.', substantia iii^jra ; 17,
nucleus ruber; IS, nucleus lateralis sniierior i I'leclisif; i or nucleus iiinoin-
inatus < von liechterew) : /.''. cori)Us pineale ; ^'(i. nuclei corporis maminillaris ;
21, nucleus hyipothalainicus corpus Liiysi i ; ;//, nucleus corporis Kcniciilati
niedialis; Jj' , nucleus corporis f;eniculati lateralis; J-!, nucleus h ntil'orniis ;
i',{, {;i"i.v maff;'r about the venlriculns fertius; J-'i. nucleus liabciiiihe ; i'.s',
tliahunns; ,'.''. corpus striatum; ./'/. nncleiis fastigii ; ill, niicU us globosus;
3^, uucleiis eiiiboliforinis; .>'.;, nucleus deiilatus.
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GI10UPIN(J AND rilAIXIXG TOGETFIEIl OF NEURONKS. 707
tho iirisa leiiticularis, is opposed by von Monakow and by tbc-
Dejeriues. Von Monakow, from studying degenerations, thinks
that the lenticuhir nucleus and the ansa lenti(;uhiris take no
part in the formation of the lemniscus, or at the most an en-
tirely minimal part. The Dejerines have examined three cases
of very old lesions involving the island, the operculum, the pu-
tamen, the caudate nucleus, and tlie globus pallidus without in-
jury of the internal capsule or the oj)tic thalamus. In these cases
there was a more or less pronounced degeneration of the ansa
lenticularis and of the lenticulo-caudate fibres going to Luys'
body. These degenerated libres passed through the internal
capsule and could be followed into Luys' body and into tlie
thalamus, but there was absolutely no change in the medial
lemniscus.
Flechsig, in his latest publications, does not distinguish
sharply in the hyj)othalamic region the fibres which represent
the upward continuation of the lemnis<'us from the other cen-
tripetal fibres of this area (fibres of the capsule of the red
nucleus, fasciculus longitudinalis medialis, and longitudinal
fibres of the formatio reticularis). He grants, however, that in
all probability a large proportion of the fibres of the lemniscus
are interrupted in the thalamus. Iloesel, again, in one of his
later arti(!les,* has modified his earlier views so as to bring them
more into accord with the doctrine of ^lahaim and von Mona-
kow. There is some danger in reading the articles of these
various writers of misunderstanding just what each means by
the term " cortical lemniscus " (/t'/y/rAv/.sy7//p//'i"). The term in-
dicates the portion of the lemniscus wluL-h is connected either
directly or indirectly with the cortex. According to von Mona-
kow, Mahaim, and others, all, or nearly all, of the " cortical
lemniscus" is indirect — i. e., it is interrupted in the thalamus
— while according to the view advanced b\ ioesel in his first
article the most of the " cortical lemniscus " is direct.
The utmost that can be said at present is that the weight of
evidence is in favor of the view that the majority of the fibres
of the medial lemniscus are interrupted in the tlialamus, though
some axones, helping to form the lemniscus, doubtless extend
all the way from the nuclei of the medulla to the opposite cere-
H
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* Hoesel. Heitnijfe ziir Atiatoinie der Sclileifen.
Leip.^., Bd. xiii (1894), S. 546-5.5!).
Neurol. Centralbl.,
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TIIK NKRVOUS SY.STP:M.
bral cortex, since Tschermuk * Ims been able, after destruction
of these nuclei in the cat, to foHow (le<jenerate(l fibres throu{,'h
the thalamus directly out to the cortex.
A full rc])ort (if Tscherniak's investigations in this connec-
tion has been subsc<j""ntly publislied.t In his experiments he
destroyed the nuclei of the funiculi in three cats. The symp-
toms whicli resulted corresponded to those previously found
by von liecliterew J in dogs, aiul by Ferrier and Turner ** in
numkeys.
Von lieehterew in dogs injured the nucleus funiculi gracilis.
The animals tumbled about when they attempted to walk, and
swayed on standing. There Wiis lu) disturbaiu-e of cutaneous
sensibility to be made oixt. Similar symptoms could be pro-
duced by cutting the funiculus gracilis in the upper part of
the pars cervicalis of the spinal cord.
In monkeys, Ferrier and Turiun- found as syniptoms result-
ing from injury to the dorsal funiculi restlessness on the part
of the animals aiul a sprawling character to the body on exer-
tion, and the animals exhibited a tendency to fall backward.
As far as they could make oxxt, the sensations of touch and pain
were unimpaired, and the capacity for localization did not ap-
j)ear to be disturbed. The interference with the equilibrium of
the animals vanished in a few days.
Tschermak's cats showed m.»rked symptoms at first of dis-
turbance of equilibrium, but these soon disappeared. On the
first or second day after the lesion the cats, on attempting to
walk, deviated constantly toward the side of the lesion, and often
fell when they attempted to use the paw of the injured side.
While the contra-lateral fore paw could be used almost normally,
the homo-lateral leg sprawled about on attempts io move it.
One animal kept the hind leg on the alfected sid( lifted when
it walked. Even on sitting, all three animals showed lateral
* Tsclicrinak, A. Notiz bctroffs des Rindciifcldes dor Ilintcrstranj;-
bahnen. Neurol. Ccntralbl., Leipi;., V.d. xvii (t8!tS), S. 1?)9-162.
t Op. ciL. Arcli. f. Aiiat. u. Physiol., Aiiat. Ablli., Loipz. (1898), S. 291-
400.
I von Heehterew, \V. Arch. f. Aiiat. u. Phy.siol., Aiiat. Abth., Leipz.
(1890), S. 489.
* Ferrier, D., and Turner, W. A. A Record of Experiments illustrative
of the Syinptt)niiitolojjy and Dejjenerations following Ijcsiinis of the Ccrc-
belluin, etc. Phil. Tr., Lond., vol. clxxxv, H, pi. '2, p. 75.').
UKUUPING AND CHAINING TO(}ETIlKIt OK NKUUONKS. 709
swaying to the side of lesion. Cutaneous sensibility appeared
to be normal, .\fter from two to five days the disturbances of
eciuilibrium had prac^tically disappeared, though in one ease
marked symptoms continued until the death of the animal at
the end of sixteen days.
The consensus of opinion at present is, therefore, that de-
struction of the nu(dei of the dorsal funiculi does not interfere
with the sense of touch, the sense of pain, or the capacity for
localization, as far as the skin is concerned. The long fibres of
the dorsal funiculi, accordingly, can scarcely be concerned in
the mediation of the centripetal impulses concerned in these
sensations. Their function appears to be rather that of con-
duction of the impressions of muscular sense, a view which is
supported by observations iu tabes and other pathological con-
ditions in human beings.
In Fig. 457 I have reproduced some of the illustrations ac-
companying Tschermak's article, which show degenerations as
revealed by Marchi's method after destruction of the nuclei of
the dorsal funiculus, and some of the parts just ventral to this.
The fibne arcuatne interna? are seen to be markedly degenerated.
The finer blackened fibres going to the nucleus Js. hypoglossus
and to the lateral and ventral portions of the formatio reticu-
laris grisea probably correspond to degenerated collaterals.
Large numbers of degenerated fibres can be seen passing into
the nucleus olivaris inferior. A moderate number of degener-
ated fibres extend from the degenerated contra-lateral stratum
interolivare leminsci along the periphery of the medulla into
the ventral part of the corpus restiforme. On their way to the
cerebellum some degenerated fibres go into the vestibular nu-
clei. The degeneration in the formatio reticularis alba, includ-
ing the fasciculus longitudinalis medialis, is well shown, but is
due not to the injury of the nuclei of the dorsal funiculi, but
rather to the destruction of the parts ventral to tl.'s at the time
of operation.
The degenerated interolivary layer can be followed in the
pons into the lemniscus medialis. Fine degenerated fibres can
be seen passing from the lemniscus dorsalward into the foi-matio
reticularis grisea, and also ventralward into the nuclei pontis.
Higher up distinct bundles of degenerated fibres can be followed
into the nucleus colliculi inferioris. Higher there are fine de-
generated fibres passing medialward to the formatio reticularis.
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TIIK NKItVUUS SVSTKM.
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(llfol'IMNd AND CIIAIXINi} ToCiKTIlKU (»F NKl'UOXKS.
iiiul vciitriihvaril into the siil)stiiiitiii iii<;rii. In the liypotlialii-
mic vcj^ioii tlic (lef^t'iicnitiMl fihri's of tlic lotimisciis lie scuttcrcd
over 11 nitluT large urea situated medial to the corpus geuieu-
latuni mediiile. Farther frontalward tliey pass into the liihis
thalanii. The area of degeneration in the tegmentum is ap-
proximately trianguhir in shape in eross section. From the
dorsal apex of this triangular area single hlackened fihres ean
he followed through the pars dorsulis of the commissura pos-
terior cerebri to the nucleus lateralis supi'fior of the opposite
side. Of the fibres which pass into the hilus thalami a great
juunbor seem to disappi'ar in the ventral nuclei of the thala-
mus, but many run into tlie lamina medullaris media, and into
the lamina medullaris lateralis as well as into the lateral half
of the zona reticularis {77/ti/(ntnissr/iii/f).
The rest .)f Tschcrmak's description is of the deepest intiT-
cst. He follows a considerable number of single fine collaterals
(never in bundles) radiating out to the ventral and ventro-lat-
eral parts of the reticular zone to pass transversely into the
basis pedunculi and into the ca))sula interna. (>f the fibres
which pass farthest ventralward, some go medio-ventrally into
the nucleus hypothalamicus (corpus Luysi) ; farther on single
fibres can be followed into the commissura su])erior Meynerti
(or so-called cojnmissura hy])otlialamica), which passes down
between the basis pedunculi aiul the tractus o})ticus. They ex-
tend to the nucleus lentiformis of the opposite side.
But in addition to these Tschermak is able to follow a much
greater nund)er of isolated degenerated fibres through the cap-
sula interna into the nucleus lentiformis; these lil)res appear as
fine Ijlackened droplets, especially in the glo1)us pallidus. A
nundier of somewdiat coarser fibres pass through the himiuie
medullarcs (and also probably through the capsula interna) to
enter the corona radiata. Most of the fibres, however, which
enter the coroiui radiata arrive there directly by way of the
capsula interna. These degenerated fibres of the corona radiata
pass out, according to Tschermak, chiefly to the cortex of the
gyrus coronalis, and to the adjacent marginal parts of the gyrus
ectosylvius (pars anterior), and to the gyrus suprasplenius (])ars
anterior), without, however, going to the gyrus fornicatus sen
cinguli. The cortical distrilnition of these fibres is well illus-
trated in Fig. 458.
As a result of his studies, Tschermak concludes that four
47
1
712
TIIK N'EUVOITS SYSTEM.
principal cciitral-uxonc nctiroiic systems orij^inatc in tlio nucU'i
of the dorsal funiculi. The first two of these systems whicOi
pass to the ccrchellum have already been di'scri'ied in Chapter
XX.XIX. 'I'lie other two systems whieii pass to the cerebrum
demand furtlu'r discussion here.*
Gyr. supra.fp1cnin/} s. mar(/ina7is
Ci/r si</r)wu7rs
Gyr. (ii/r
cntc. cnic.
\^'
Gyr. supvdsijlviuf,
1 wmslonwlischi' Kat/ev-
I /' wincbw/j
Meynert 's
Zob olfact. j
Guv. coronaJis
Gyr sylviaciis
> Gyr. cktosylvfuf:
Annsfomosis
Fi(i. JoS. — Cortical area of tcrmiiiatioii of Icniiiisi'iis tilircs in liic <'at. lAftcr A.
Tsclicnimk, Arch. f. Aiiat. ii. Physiol., Aiiat. Al)tli., Lcipz., IHltS, S. :55:?.
Kifi. -.1. 1
The medullated axones of tliese two neurone systems are
those which we have already seen passinji; as internal arcuate
fibres through the decussatio lemniscorum into the stratum in-
terolivare lemnisci and into the lemniscus medialis (Figs. 308,
liOit, ;522, and '.Vl'ii, vide supra). While the majority of investi-
gators who have worked with Marehi's metliod have never been
able to follow degenerated fibres of the lemniscus above the
thalamus, Tschermak has succeeded, as we have seen, in fol-
lowing in his three cats a certain number of fibres still farther,
even to the cerebral cortex. He concludes, therefore, that a
* Die heiden kremenden Ilinterstrangkern-GroHshirnsysttme (Ifinli'i-
strangkern-IIauptsclileifensystemc) of Tscliermiik.
u
tiliol IMN(i AND CIIAINMNCS TOClKTIIKlt OF NKrUONKS.
V.\
■V A.
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5 tiro
■uate
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508,
been
e the
fol-
fther,
lliiit a
ifhifi'l-'
not iiu'(»iisi(l('iMl)l(' iiiiinl»i'r ol' lihrus I'roiii tlic iiiicU'i of tlii' dor-
Kiil funiculi of tiie oppositi; side, instead of dclinitcly tcrniiiuitinfj
in the tluilinnus, pass tlironj^li it in tiic form of sc^attorcd ili>n's.
'Plicsi' longer fihrcs, wliicli do not stop in the t lialanuis, follow
dilTcrcnt paths. All those most vi'iit rally situated in the radi-
ating fan of the lemniscus nu'dialis (//^//7//,sv7//r//"(") very soon
break tiirou^xh the narrow ventral mar^^inal zone of the zona
retieulai.s {Tlinhiiiiiisschtilc) and pass in a curved direction
latero-ventralward to enter the basis peduneiili. Farther on a
nund)er of other lihres more laterally situated follow the same
course. It is just at this level tliat the white fibres of the basis
pedunouli are continuous latero-dorsalward with the capsula in-
terna which lies between the zona reticularis and the nucleus
lentiformis. The most ventro-medial portion of the lihre-inass
surrounds the nucleus hypothalamicus.* The de^feiierated lihres
referred to are found in the cat to jjive ofT, on i)as!»inff throu<,di
the basis peduiundi, collaterals to the nucleus liypothalamicus
which lies medially from tlicm. A relatively smaller part of
the degenerated fibres here turn nu'dialward and run alouii the
veutral nnirjiin of the basis peduneidi ; they lie immediately
upon the tractus opticus aiul run toward the region of the tuber
cinereum. These fibres form oiu' constituent of the conimis-
sura superior Meynerti (commissura hypothalamica nu'dia of
Meynert),and after crossing the middle line arrive, by a similar
path between the peduncle and the optic tract, in the globus
pallidus -f the nucleus lentiformis of the other side. .Vccord-
ing to Tschermak, therefore, this commissure is part of a high
decussation of axones of the lu'uroiu) system which extends from
the nuclei of the dorsal funiculi to the cerebral cortex.
The greater part, however, of tliose fibres whicli go ventrally
and ventrolaterally out of the thalamus and j)ass through the
l)asis pedunculi arrive in the nucleus lentiformis of the same
side, partly by running lengthwise (at lirst along its base ami
then beiuling up into the nucleus), partly by crossing over
directly into the globus })allidus. It would seem likely, at first
thought, from the large number of degeuerat(>d fibres met with
here, that tlu' globus ])allidus receives no itu'onsiderable number
of such fibres, but Tschermak stati's that in reality not very
* 111 the cat this strucliirn is by iiu luefins so definite and eoinpact a iciis-
shaix'd mass as in niiin.
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rilK MllfVors SYSTKM.
nmny Htern fil)roa tcniiiiiutu here, the majority "f terminals in
this rcjiioii hciiij; (■((lliiti'rairt. On tlio otlicr hand, he is of tlw
opiiiinii tliat the majority of the fibres (cliiclly hy way of llic
iamiiia mcdullaris mi'tliaiis and tiic lamina nicdnllaris lateralis,
but in part, also, by way of the layer of whiter matter between
tile putameii and the eortcx of the island of Reil) leave the
nncleus lentiformis a<jain in order to i)ass tlirouj,'h the corona
radiata, and finally arrive in the cortex of the pallinm. 'Plie
axones then from the nuclei of the dorsal funiculi which ^^o
directly to tho pallium make a curious loop-shaped excursion
through tho nucleus lentiformis. A ctu'tain number of the so
calle(l (lirrrf libr(\s pass straij^ht throuj,'h the zona reticularis
on their way from the thalamus to the capsula interna, and
ascend int(» tho corona r-idiata, especially along tho obli(jue
dorsal surfaco of tho nucleus lentiformis.
!f other investigations contirm tin* results of Tschermak, I
would suggest that the system sending axones from the nuclei
of the .iorsal funi(;uli, without interruption to the cerebral cor-
tex be called tho si/.s/ciim {nfuroninini) iiiifi'lt'>/n>/)/i(fl(i-/)(!//iii/r.'*
On tho other hand, the system sending uxoiu's from the nuclei
of the dorsal funiculi to termimite in the ventral region of the
thalamus of tho o])posito side could be designated tho si/s/oiki
{i/ciiroiiicKiti) iiii/i'/i')in'p/i(i/(i-//n(/iiiiiicinii. j Whother or not a
xfixffiiut {leinniticdlt') ini/rlciircj>fi(i/(i-pf(/h'(il(' actually exists ii: hu-
man beings remains to bo proved. The jjroof of tho existence
of such a system in the cat, however, taken together with the
researches of IFoesel and of Flechsig on human beings, make it
unsafe to deny its possibility.
Tschornuik discusses in his article tho portion of the cortex
in which the direct cortical lemniscus terminates in tho cat
and attempts to a'"rivo at certainty with regard to the corre-
sponding region in man. Whereas many observers have con-
sidered tho crucial sulcus of the dog's brain as tho equivaloiit
of the sulcus centralis Holandi of human beings, Moynert J
was tho first to recognize that the flssura coronalis, not tho fis-
sura cru(uata, of the cat is the homologuo of tho sulcus centralis
* Ddx /iTi'iizcndr f!iiiti'i:ifr<tii(/h'rn-(tr(inn/i Irtirlndenayi^ti'm of Tscliormiik.
f This kri-Kzi'Hde I/iiiti'rxtr(t)!i;/{prn-7yiii/(iiniin!<i/>i/i'w of Tschcnniik.
\ Meyiii'rt.Tli. Dio \Viii(lim,i,'(Mi (lert'onvexcn Ohcrtliiclio (l(>s^'ol•ll('rl^irIls
boi Monscheii. Affeii und liaubthieren. Arch. f. Psyehial., Herl. (IHTO), l?il.
vii, S. 257.
(iUorpTXf; AM) ciiAiMNr; 'nujKTiiKii of xkuuones. 7ir,
of num. All tho cvidoncH! pocH to prove tlmt thin view is cor-
rwt, luid 'I'Hclu'rnmk ufjfrccs with MeyiiiTt. lie ushuiiu's, thcro-
fori', that his tlircc^t corticiil system of tho lciiiiiisc;us in the cat
fiids ill tiu' n'j,Mon of the cortex homologous with the f,'yrus
centralis posterior (»f luuii.
The host review of the history of the development of our
knowled^'c concerninff the lemniscus I know of is that }(iven l>y
Tscherinak.* Siiufo this has appeared so recently ( IS'.IS), und,
moreover, has heen pul)lished in a journal gcju'rally accessihle,
it iuis not seemed necc^ssary to nuike any attempt ;it an ex-
haustive review of the literature here. It hus seemed to me
wiser to lay emphasis upon the main features of the suhjcct,
citiuf,'' only the more imp(»rtaMt researches rather than to deal
very fully with all pui)licati()ns bearinj,' on the topic, for in the
doimiin of the lemniscus, perhaps more than ;:nywhere else in
the central nervous system, the Itc^nnner, on aj)proachinf( the
hihlioj^raphic forest, runs in danj,'er of "■ losinji^ sight of the wood
on account of the trci's."
For those who wish to delve deeper into the l)ibliogra[)hy,
however, the articles of FleclKsig,f K(linger,J von Hechterew,**
* Oik clt.
f Flcclisig, P. Die Tieitiiiif^sbalmpti iiii ricliini uiul KKckcimiark, etc.
Leipzig, Hvo. (lH7(t). — I'elier liit; Vcrliindiiiij^eii der lliiiterstriliige mil lieiii
Creliirn. Neurol. Cetitralbl., Lcip/.., Ud. iii (1HH5). S. 07-100.— Ziir Lehre
VOID ceiitnilcii N'eriimf der Siiiiicsiu'rveii. IhiiL, Hd. v (1HH6), S. .jt.">-.").")l. —
Ziir Ariatoinic mid Kiitwicki'luiigsgest'iiiclitcf der liciliiiigshahiieii iiii (Jross-
hirn des Mcnschen. Arch. f. Anat. u. Physiol., Aiiut. Abtli.. Leipz. (1P81),
S. 13-7-'). — Plan (h's inenschlicheii (Jeliiriis. Aiif (rniiid cigeiier I'lilersuch-
luigeii entworfeii., Hvo, Ijeipz. (1HH3). — Die Ijocalisatioii der geistigen Vor-
gilngi init besonderer neriicksiciitigung iler .Siniieseinptuidungeii des Men-
scheii. Leipz. (1806).
X Kdiiiger, \: Zur Kenntiiiss des Verlaufes der lliiiterstrangfasern in
der Medulla oblongata und ini hintcren Kleinhirnsehenkel. Neurol. Central-
l.l., Leipz., Hd. iii (ISH.'i), S. 73-70.
** von IJeeliterew, VV. Untersuchungen ueberdio .Schl"ifenschieht. Her.
d. math. phys. CI. d. k. siichs. Gesellsch. d. Wissenseii., Leipz. (1885), 4 Mai.
— Ueber eine bisher unb(>kaunte Verbindung der grosseii Oiiven init dein
(Irnsshirn. Neurol, f'entralbl., Leipz., H.l. iv (1885), .S. 104-100.— I'eber die
Schleifensehieht auf Grunde der Hesultate von nach der entwickelungsge-
.•(ehicht lichen Methode ausgefiihrlen I'ntersuchungen. Arch. f. Anat. u.
Physiol., Anat. Abtii., Leipz. (IWI.')), S. ;{70-;]0r).— Die Leitungsbahnen ini
Gehirn und lliickenniark. Deulsch von 1\. W'einberg, IL Aufl., Leipzig
(1899).
8f <
m
"^ t
m
If' 'I
716
TFll-: NKUVOUS SYSTKM.
Darkscliewitscli iiiid Fri'iul, * jiiid ('niiiior f on niycUni-
Ziitioii. thosi' of Meyer, X Seliultzo, ^ Spitzka, || Selinider, '"^
voii Monakow, ^ Maliaiiii,| Vejas, | Loewciitlial, | (i('I)lianl,**
voii licchtorc\v,ff Wordiiig,^ liossolimo,'*** Dejoiiiio,|||| Schaf-
* D.irksclicwitscli, Tj., iiiid S. I'Voiid. Tcbcr dii' Hiv.ii'huiij; dcs Strit'k-
korpor.s ziiin IlinttTst rani,' mid IIiiit('i'stnuii,'.ski'rii, iiobsl IJeiiiori „iigi'n ucIkt
zwei Kcldcr dcr Obloiijjiitii. Neurol. Ceiitralhl., Loipz., Hd. v (1886), S.
13l-l'2n.
f ('raiiicr, A. Ik'itriijfc zur fciiicreii J., dloaiiu der Medullii oljloiiijata,
dcr Mriu-kc, etc. Jena (1894).
\ Meyer, P. Uel)er eiiicn l-'all von PonsliiiniDrrha.i^ie niit secundiireii
Dejjeneralionen iler Sehleit'e. .\re!i. 1'. I'sycliial., Merl., 15d. xiii (1882), S.
6;i-iis.
* ScliultZ(\ 1"\ Hi'itriij^e ziir Patliolnf^ie and jjatliologiselien Anatomie
di's centralen Xervensyslenis. Arcli. palli. Anat. ete., Herl., Hd. Ixxxvii
(188'2), S. olO-iUO.
i Op. cil.
"^ Scliradei', A. Imh (Irossliirnsehenkellierd mil sccuadilren Degenera-
tiiUKMi dcr I'yraniide and llaube. 8vu, Ilalle, 1884.
^ von Monakow, (". l''xi>i'riinentelU' and (>allio]()!;iscli - anatdiaisclie
riilersuchangiMi aeber die Me/ielnaigen der sogenaauteii Seiispliiire zu tlea
itifraeortieaieii Optieusceiitren iind zani N. optieus. Arch. f. I'syeliiat.,
Herl., Md. xvi (ISS.")), S. 151 ; :!1T. — Kxpi'riaieatelle and palhologisch-anato-
niisclie UntersiK'lumjren ueber dit; llaabearegion, den Sehhiigel and die
Hegio sabtlialaini(!n, nobst Heilriigen zar Kennttnss friili crworbeacr Uross-
and Kleinhira defeete. Arch. f. Psyehiat., Merl., Hd. xxviii (18!tr)), S. 1 ; :{S6.
X Mahaiai, A. Op. fit.
X Vejas, P. Experinicntcllo lieilriige zur Kenntniss dei' Verbindangs-
bahnen iles Kleinliirns and des Verlaal's der Fanicali graciles und cuneali.
Areh. f. Psyehiat., Her!., Hd. xvi (1883), S. 200-214.
I lioowenthal, X. Xote relative li I'lvtrophie anilateral^ de la colonne dft
Clai'ke obsevvee ehez an jeane cliat, open' ii la jiartio inferieure da bulbe
raeliidienne dans la premiere (|uiazaint> apres la naissanec. iiev. aied. de la
Saisse roin., Geneve, t. vi (IMSfi). pp. 20-27.
** (iebhard, F. Seeundiire Degenerationen nach tabcrkaloser Zorsto-
raag des Poas. 8vo, Ilalle (188?).
tf Ton Hci'literew, \V. Zar Frage iiber die sccundiiren negenerationea
des llirnsehenkels. Arch. f. Psyehiat., Herl.. Pd. xix (1887). S. 1-17.
XX Werdnig, G. Coacrenient in der rechtea Substantia nigra Suninier-
ingii mit aaf- and absteigcnder Degeneration der Sehleife aial thcihveiser
Degeneratioa de.s 11 irnsehenkelf asses. Med. .lahrb., 1888, Wien, a. F.,
Bd. iii( 1889). S. 447-477.
** Hossoliino, (i. Zar Physiologic der Sehleife (Kia Fall von (ilioinatose
ciaes Ilinterhorns des RUokenmarks). Arch. f. Psyehiat., Herl., Hd. xxi
(1S89-90). S. 897-909.
Ill Dcjerine, .1. Sar an eas d'hemiana'sthesie de la .son.sibilite generale,
observe chez an heinipl6gi(|ae et rrlevant d'ane atrophic da faisceau rubane
iVip*™ »f
., <\". 1 N
GROUIMXG AM) (MIAIXING TOUETIIKU OF XKrUOXKS, 717
for,* Ilonsclu'ii, f Singer uiid Miiiizci-, J; Miuguzzini,* lloi-scl, ||
JJruci','^ lloirniauii, ^ Mott, J FerriiT and 'rurncr,! (Irciwc,!
Hk'lscliowsky, ** MiiUer and Meder,ff S('hlcsinj,'t'r,|;t Saxor,"'*
.Mayer nil on degenerations (in liiiman beings and in experi-
mental animals), may be recommended.
(Ic Ikfil. Arch. (Ic jiliysiol. iioriii. rt path., I'ur., 5. s., t. ii (IHDO). pp. r).">S-
flTO. — Dojerine, J., ct Dejeriiic, Mnu-. .1. Sur Ics connexions du niluiii do
Ucil avpc hi corticiilitfi (•er6ljnilc. Conipl. rciul. S<ic. do biol., Piir., 10. s., t.
ii (1895). pp. 2«r)-:J!tl.
* Scliaffcr, K. IJeitraf; ziir Lelirc der soeundiln'n mid iiiultipU'n Dogon-
cnitinn. Arch. f. ihiiIi. Anal, cle., Ik'rl., \\d. cxxii (1H!»0), S. 1 ','">- l-l").
f Ilciisciit'n. S. K. Klinisclic und analiiinis<!hc l{citriijj;c ziir I'athoh)gic
di's (ichirns. Th. 1, I'jisahi (1N!»()|. S. 48; 65.
J SingiT, J., ot K. Miin/.cr. Hoitriigc ziir .Xnatoniic dcs ("cntrahicrvcii-
systcnis, insbcsondcriMh's l{iickcnniari<cs. I)('id\schr. d. Akad. d. Wisscnscli.,
Wien. Math.-nal urw. CI., Hd. Ivii (1890). S. Tifii).
* .Minga/zini, (f. Intnrno al dccorso (U'Uc filirc apiiarlciu'iiti al |i('d\iii-
ciUiis nicdius cprclx'lli cd al corpus rcstifornic. .Vrch. per Ic .sc. ined., 'Porino
e I'alerinii, vol. xiv (IMOO), pp. 245-202. — I'atholoirisch-anatoinisehe Unter-
siichungen iiher di'ii \'"rlatif einiger Xervenbahnon des (Vntraliiervensys-
teiiis des Menschen. IJeitr. z. jialh. Anat. u. z. allg. Path., Jena, I?d. xx
(bSltO), S. 413-476.
II Op. cit.
■^ Uruci!, A. On a Case of Descending negencration of llie Lemniscus,
Coiise(|Ueid on a Lesion of the Cerehrmn. Brain, Lond., V(d. xvi (189;!), pp.
465-474.
() IIolTniann, J. Zur Lehre von der Syringoniyelie. I>eiitsclic Ztsehr. f.
Xerveidi., Leip.'.., lid. iii (1892-'9;{), S. l-i;?6.
I Op. cit.
I Op. cit.
J (froiwe, .1. Kin solitilrer Tidierkel ini rcchten Grosshirnscheidiel hezie-
hungsweise in dcr Hanbo, mit Degeneration der Schleit'e. Xetirol. Centralbl.,
Leipz.. Hd. xiii (1894), S. i;?(); 184.
** Op. rit.
ff Miiller, F., und E. Meder. Fin Heitrag zur Kenntniss der Syringo-
niyelie. Ztsehr. f. klin, Med.. Berl,, Hd. xxviii (l.s95), S. 117-i:i8.
\X Sfddesinger, H. Henierkungen iiber den .\ufbau der Si;hleifc. Xeurol.
Centralbl., Leipz.. Hd. xv (1896). S. 146.— See also. Arb. a. d. Inst. d. Cenlral-
nervcnsyst. a. d. Wien Univ. (1896), II. 4.
** Saxer. F. Ainitoinische Heitriige ziir Kv-niitniss der sogenannten
Syringoinyelie. Beitr. z. |)atli., ,\nat. n. z. allg. Bath., .lena, B<1. xx (1896),
s. ;{;{2-;i98,
III Mayer. C. Znr Kei\ntni.ss des Faserverlaufes in der llaube des Mittel-
imd Zwischenhirns auf Grniid eines l<'alles von secundiirer aufsteigender
Degeneration. Jahrb. f. Psyc^hiat., Leipz. u. Wien, Bd. xvi (1897), S.
221-233.
li;
\u
(.!«-'
W''^ \.
[1,1
f
!,) t
ClIAJ'TKK XLVIII.
r'KXTTUPKTAL I'lFtKKS IX TIIK FASCK TLIS LOXCilTrDIX.V I,IS
MKDIALIS.
Cases (if sefoiidary (lei^piiorat lull — Studies by (uilgi's iiietlidd — The nucleus
of Darkscliewitseli — Adjacent bundles of white fibres in the develop-
ing brain.
(?>) The Fasciculus Longitudinalis Medialis.
TiiK course and roliitions of the axones in this bundle have
boon tlie suhject of much dispute, and althoufih an inniionse
amount of work has been done to determine the origin and
termination of its constituent fibres, we are still unable to make
entirely positive statements in this connection. The connec-
tions of the l)undle below with the upwanl continuation of the
fasciculi proprii of the ventral and lateral funiculi of the cord
are certain. The connection between tlie two is formed by
means of a well-marked curve (Fig. 4.')'.)). Tlie intimate rela-
tion of the bundles to the eye muscle nuclei in the midbrain
is also very definite, but just how far downward fibres extend
and just how far upward its fibres reach we do not yet know.
Nor are we certainly informed as to the exact number of ascend-
ing fibres and the exact number of descending fibres in the
fas(ncidu8. While many observers assume that the majority of
fibres descend — tiiat is, are centrifugal in conduction direction,
having maiidy to do witli reflex activities — others liold that the
majority of the fibres ascend and are centripetal in conduction
direction, representing the sensory lind) of reflex arcs ami pos-
sibly a central conduction path for the passage of sensory im-
pulses toward the cerel)ral cortex.
The study of cases of secondary degeneration thus far has
thrown but little liglit upon the subject, though in the case
studied by Jakovenko * the degeneration of the bundle stopped
■ * .Takovenko, V. K. vopr. o stroenii zadnjapo prodol. puehka (fasciculus
longitudinalis modialis). Vestnik kliti. i sudebnoi psichiat. i novropatol., St..
Petersl)., vol. vi. pt. i (IHHH), pp. W»-!»H. _
718 ^ "^ ' '"' ' '
M,
OROUPING AXD CIIAINlNd TOCKTIIKIi OF NKIKONKS.
■11>
suddenly autiM'iorly on rciiidiiiig tlio level of the mieleus of
l)iirks(die\vits(di.
(iolgi's method htis proved definitely the existence of nu-
merous axones passin<( into the fasciculus lonf^itudintilis nu'di-
alis, axones which have had their oriifin in the cell bodies or
Dfntuxntin FaKcictihis
iii'rriiniiii iDiiiiituilhialis
Xiiclvusnrni trochletiiinm. meiiUtlis. Radi.i- N. facialis \,i<hn^mrri
rniinnismra /..V.;.;.". 1 /l\ Ujeiiu internum}. A///«'!//i'ss/.
poslerior
Cor,nix c,rel„i.
pinviilf.
Hvclcux
A. iiriiln-
motorii.
/
/ylussiijilitiii/nyii.
Xiir'i'iiii fniiicnii
yiacilis.
Kdnrirulit.t
(ir<icili.t.
('(irpus
mtiiiimillarr.
DecHssatio Fihrrr
briichii ti'ans-
coiijunctivi. vcrmv
(prof an-
dm) pontis.
(supf rfif id Ics ) III i-flialis.
pontis.
Ftisrictili
longitiidi-
iKilfs ( pyra-
miV/ri/cs).
t?
Fl<i. 45!). — A siKittal scctiiiii of tlic iiudiilla olilviiKiitii, iiinis. aiul iiicsciicciilialim
pantllt'l and ('lose to the liiiildlc line: child a^cd tlircc liiiilitlis: ini'tlind of
Wfisicrt. I Alter A. Hriicc, Illustrations of the Nerve Tiiiets in the Mi<i- and
Hind Hrain and the Cr.inial Nerves arising therefVoni. Hdinh. and
liiind., ISifJ, ](l. xxvii. Via. 1.) The I'ascienliis loii;;itudinalis niedialis and
its relation to the tascicuhis ventnilis iiroprius of the spinal cord are partien-
hirly well shown.
dendrites of neurones situated in tlie nuclei of terminiition of
the sensory cerebral nerves. Axones of the cerebral conduction
path connected with the vestibulttr and other sensory nuclei
entering the fasciculus longitudiiuilis mediiilis luive been re-
ferred to above. On the other hand, (iolgi prepiinitions of the
midl)rain have shown large nmnbers of tixones passing from
cells in the superior coUiculus of the corpora (|uadrigemina
and in the nucleus of Diirkschewitsoh, which pass ventnd to
the nucleus nervi ooulo-motorii to decussate with correspond-
Wl
i
I
ill.
i
1
t r
i.
!
Si
h
'
1 i
'.■f
'1 ,
if f
U
I [
il:
!1'
1 20
TIIK NKltVOUS SVSTKM.
iiifj fibres in tlic middlo line aiiil to ciilt'r llic ventral portion *
of the fiisciculus l()ii<,Mtu(liiialis nii'dialis to flcsceiid in it. Siiiii-
FlO. 4fl0. — i^agittal section throtif;!! livaiii of I'o'tal iiioiiso in i)laii(' of 1 lie fasciculus
lonnituiliualis uicilialis. (AftcrS. Kainon y ( ajal, IJcitran /.nm Stuiliuin ilcr
Medulla Olilon^ala, etc.. Lei])/... ISOli, ])..") J, V\k. 1 1. i .1, fasciculus lou^itu-
(liiialis luedialisat level of (ions; It, collalerals finni it (o nucleus N. t.rocli-
li"aris; (', I'ollaterals to i.ucleus N. oculo luotoiii ; /'. end nunilicatious in
nucleus fasciculi lonijiiudiualis uiedialis; /■'. tilires ^oin;; past the fasciculus
retrotlexus to enter tlie tlialaunis; I'.. I'ascicnlus retrollcxus Meyucrli ; ^r,
nucleus ruber; //, fjanKliou iutevpednncnlare ; /. ai|Ueductus C4'relivi ; /.,
space lietwcen corpus uiauiinillare an<l pons ; n, cell in fjaufilion interpedun-
culan' ; h, lihres oi' de4'U.ss;itio te-juienti dorsalis Meynerti i </. lower motor
neuron<'s in nindeus N. oculo-iuotorii ; ,), cidls of stratum K''ist'uni central'-
witli ascending axoues.
* The so-called praedormlen LongHhrmdel of the (^eriiian.s.
!• m. ! «ii ,1 Ji mv !. I .i,si!iHH|u^)|,j^_
(HIOI'I'INO AND CIIAININO TOGETIIKIt OP NEUltONKS,
1 21
liir iix(iii(\4 iirising t'rniii the superior liiltTiil nucUiUS of l''locliHi{^
pass into llu; I'uscuculus lon*^'it iitliiialis iiicdiiilis of tii(! suiik; Nidc,
or lifter (le(!USHiitioii into tliut of tiie opposite .-.ide, from \vlii(;li
point they (les(U!n<l. It roriiiiins for futiinf work to detoriniiK!
tlie reliitiv(^ Tuiinhcr of ascending' and doscM-ndinff fil)res. It is
Itelieved hy van ( Jeliueliten tiiat in the trout and sahiinaud<!r
the majority of tho fihrort of the l)iindh! (h'seend (motor and
rellex (ihnvs). fiarge numh(!rs of eolhitcruls are {^iven olT from
tlie lihros, prohal)ly from hotii ascendin<^ and (h(S(!endin<f lll)r(fs
of the faseicidiis h)n<fitudinalis medialis to the various f^ray
masses with wliich it comes into (U)ntaet relation in its course
(nuch'us nervi tnxddearis, nuch'us nervi ocuh)-niotorii, foriruitio
retic^uhiris f^risea). {Kif,'- -K>")
'IMie relations of the fasi-iculiis lonj,nt udinalis medialis at its
anterior (extremity an; peculiarly puzzlin<^f, and one has only to
read tint (lescri|>tions in the various text-hooks and in tlu^ ori<^-
imil arti(des dc^alinj^ with this topie to a])])r('(!iate the confusion
which exists with re<,Mrd to it. Kspecially conllictiii^f an; tho
views whi(di hav(! heen held concerniiij^ the relations to the
nuchuis of Darkscihewitscli, ami to tlu^ K''''y 'natter of the hypo-
thalamic! re<(ion. It would hv. unfruitful to discuss at leiif^th,
in the present state of our knowhidf^c, the various theories
which have Ix'cn advanced. I shall restri(;t mys(Of, therefore,
in the main, to a men^ statement of the results of my own
studies, and of those of Miss Sahiu and Miss Stein, who have
especially studied this region.
As tho fas(Mculus longitudiTuilis medialis is followed frontal-
ward it is found in the rcffion of tlu^ nucUnis nervi trochlcaris
as a compact htindle which at this level hegins to hond ventral-
ward as it (continues its course toward the cerehrum. The fihres
of the fasciculus longitudinalis medialis cauuv, into very inti-
mate relation with the nuclei of the N. trochloaris and of tho
\. oculo-motorius (Kig. 4<il), and in this region tin; nu'dial
tihres of th(! fascMouli of the two sides curve ventralward and
medialward, and come into (contact with one another in the
middle line, so that the eye muscle nuclei lie in a long trough
extending throughout their whole le!igtli.
The nucleus of Darksohewitsch,* situated somewhat anterior-
* C(. Diirksehowitsch, L. Kiiiif^e Honicrkdiif^en iieber don Faservprliuif
ill (lor hintoreii Coiniuissur ilos Gohirns. Neurol. Ccntralbl., Leipz., Bd. v
<1886), S. 99-103.
11
Itil
m
|.
li
fC!!'
i : i,
I
If:'
:
■■ ■ ;
III
722
TIIK NHIfVOUS SYSTEM.
Tr.fr. nu.D,
Fl<i. 4()1. — Ildriznntiil section tlM'iiii;;li llic iimiIuII:). )miiis, and niidlirain of a ncw-
liorn liiilic. Wciffi rt-l'al stalniiifr. Level of dnrsil part of coiims trai)e/,oi-
deiini and dorsiil portiim ol nucleus olivaris inferior. iSeries iii, section No.
122. ) C.t.. coriius trape/.oideuni ; Dir. lli-.Ciiiij.. dtcussiitio l)racliii conjiinctivi ;
Dec. Hi'rlil., coinniissure lu'tween Becliterew's nuclei; I).c.ii.i\. dorsal capsule
of nucleus rulter: F.n.i.. liUrie arcnalu' iuteniie : Fuse, riirnf., fasciculus retro-
flexiis Mi'ynerti : F.l.ni.. fasciculus lonfjitudinalis niedialis; F.l.j).. bundle
(•()Utinu<ins with the fasciculus lateralis proprius of the cord ; F.l.p.uh. dorsiil
portion of hunille continuous with fasc'-culus lateralis jiroprius of th.- cord;
7,.^. lemniscus lateralis; /,./».. lenmiicns luedialis; .V. ///.. radix .\". oculo-
uiotiu'ii ; X.Mot.W, motor root of N. Irifjeminns; .V. I'., .sensory root of X.
triijemintis ; .V. 17.. radix N. ahduceutis; .V. 17/., radix N. facialis, lull's .se-
eunda ; .V. irst.. radix N. vestihuli ; .V..\7.. radix \. accessorii ; .V..\7/., radix
N. hypof;lossi ; Xii.F.l.iii., nucleus fasciculi lon;jitudinalis mi'dialis, or nu-
cleus comniissune posterioris mhcrfr Ociihiniiitiiriiiskcni of Darksehewit.seh i ;
Nil. II. III. III., pars inipar of nucleus N. oculoniotorii ; Sii.ii.l ll.l., pars latenilis
of nucleus N. oculomotorii ; .\ii.ii.s.. nucleus olivaris superior; A'».».c. I'.,
nucleus N. cochlea' vent rails; Xii.n.i.. inudeus olivaris inferior; Xii.o.ii.m.,
inicleus olivaris aceessorius medialis : Tr.fr. iiii. />., tnict from IX'iteiV nucleus-
to the s|iinal cord. (Preparation liy Dr. ,Iohn Ilewet.son. )
OROUIMNU AND C'llALN'iXCJ T()(JHTIIKll OF NKUKONKS.
1 2:5
Fl(i. K)2. — Iliiri/.DlitJil scctiuii tlircpiiKli the iiicdullii.
iuid iiiidliraiii nf new
horn iialx
Level iirstralmii iiili roliviiri' leinnisci, ccirinis Iia|)e/.iii(leiiiii ami
iilcleiis nilicr. \Veij,'eil-l'al stainiii
Series iii, seelimi No. lUti.
C.t., cor-
])lis tra|(ez(pi(leiiiii : llci'.UrJ'diij.. ileciissalin liracliii cDiijiiiic
tivi : D.t.. <1(
Siitiii te^tiiieiiti veiitialis ( ventral temiieiilal ileriissalinii of i'drei
Ih'r.l.
lihra' an-iiata' iiUiriue (ileeiissatiii leiiiiiiscdriiiii I ; /•'./., (ilii'es (•niiliiiiioiis with
the rillli<'llllis lalenilis iil' the spin
inediahs ;
/••.)•..!/.,
/■'././»., Cascieiiliis Idiijritndinalis
asclei,.ns reti'idh
MIS .Meynerti ; /,.
.v.///., radix N. ocnhiinutorii ; S.Mtil.
Icniniseiis niedialis
nil it I ir rod
t lit' X. trij.
A'.NcK. r., sensorv rout III' N. trif;t minus ; .V. 17//. (coc/i. >. radix N.
coelUeii'
iV. 17//. I rest. I, radix N. vestihnli ; .V. I'/., radix N. ahdiieenti
.V.I//., radix
N. facialis, pars seeiinda ; .V..\7/., radix N. li.vpoKlossi ; Sn.f.l.ni., niKdell.s
fasciculi loiifjitudinalis niedialis. or nmleiis commissuiic posterioris I 'i/ic/cr
Oritldiiiiild
Nii.o.ii.m.. nucleus olivaris acci
sk'cni of Darkschewitscli) : Xii.ii.lll.. nucleus N. oculoniotorii
ssorius meilialis
nmleus olivaris in
ferii
Xit.'
nucleii
s olivaris superior
\ii.iiihfr^ nucleus
-^l.i.l.
striitiini interolivare leinnisci ; S.»/., substantia iiigr.l. (I'repar.iticm hy Dr.
John llewi tson. )
In' >
I'l i
ill' 1
'm
'J--
fi f
' f
i:ri
'■•i
li
If
i^'^
724
TIIK NKIIVOUS i^YSTKM.
ly uiul laterally (Fi^. 4(i2)as rff^ards the imck'us ncrvi oculo-
motorii, and in frontal st'crtions appcarinj; to be dorsally phuiod
as rcpirds the latter (Fi^. 4(!;5), stands in very intimate connec-
tion with the white fibres of no less than three areas. In the
first place it is direotly associiated with the white fibres of the
fasciculus lonfjitudinalis inedialis ; in the second place it is in
the direct course of the fibres (distal or ventral part of posterior
Aq.cer,
St. gr. c
m.r.
^iSilip'--
Nm
^
a
Fio. 4(53. — Tninsvcrsc section through iiu'spiiccpliiiloii, colliculi siiiM'riorcs of cor-
pora (lUiKinKciiiina and c('r('l)nil pi'diinch- of iicwlxirn hahc. i Wcificrt-l'al,
scries ii, section No. ;?St.) .I7.ee/-., a<iuc(lnetus cerebri; ('all. sup., colliculus
superior ; D.t.. (iecussjitio tennienti dorsiilis 1 fdiilnhieiiriUji' IliiKheiikii'irjiiiiinA'
Meyncrt); F.Liii.. lascieiilus loiiKitudiiialis niedialis; /•'./'//.. fasciculi pyra-
niidales in the l>asis pedunculi ; F.r.iM). fasciculus rctroMexiis Meynerti :
I, .III., h'liiniseus nieiliaiis: \ii. !•'.!. in., nucleus fasciculi loiifjitudiiialis inedi-
alisornucleus coinniissura' i>osteri()ris mhvfvr Oniliiiiiiifiirhixkmi of Dark-sclie-
witseh 1 : .\ii.ii.lll. nucleus X. oculoinot(prii ; Sii.r.. nucleus ruber; .V. ///,
N. ociilouiotiu'ius; SI. all). I)., stratum album i)rofundum ; Sl.iir.r.. stratum
uriseiim ceutrale; .*>'.».. substantia uif>ra ; o, re<;ion of Flechsifj's rii.s.s.sclilcifc ;
P. tcmporo-occipital tnu't to pons; y. fruntiil tract from |)allium to pons.
(I'repanition by Dr. .John Ilewetson. )
commissure) which extend from the superior colliculus of the
corpora qutidrigemina of one side across the roof of the aque-
duct of Sylvius to the region of the ftisciculus longitndinalis
niedialis of the opposite side. In the third pltice, ventnil to the
nucleus of Darkschewitsch is a nuiss of white fibres which ex-
tends from the region of the nutdeus ventral ward and frontal-
ward and somewhat lateralwiird, so as to pass between the middle
line and the fasciculus i 'trotle.xiis (Meynerti). The nucleus of
mi(HTlMN(} AND ('nAININ(} T0(}I<;TI1 Kl{ Ol'^ NKIUONKS.
725
Darksclicwitsch is iiitcrciiliited, us it were, as a nodal iioint at
till' jiiiii'tion of tlicsi' three inasses of tiltiTs. Tlic micli'us of
Darksflu'witsch has a very detinite outliiic just anterior to the
nuclei of the third nerve, hut farther anterior, just medial to
the j)lace where Meyncrt's bundle tnerjjes into the red nucleus,
the nueleus of Darksehewitsch comes into relation with the
gray matter of the anterior capsule of the red nucleus, and a
small Imndle of fibres, apparently belonging to the fasciculus
longitudinalis medialis, can be followed beyond the lUK'leiis of
Darksclufwitsch to the ventral jiortion of the capsule (K. Sabin).
It is very difficult to say from the study of W Cigert preparations
how many of the fibres ventral to the nucleus of DarkschewitsciJ
represent continuations of the fasciculis longitudinalis medialis,
and how many re])resent continuations of the bundle of fibres
of the commissure. Nor is it possible to say, from Weigert
preparations alone, how many fibres from the opposite superior
collieulus go past the nucleus of Darksehewitsch without end-
ing in it to enter the fasciculus longitudinalis medialis. The
best (lolgi studies of this region are those of Held and van (!e-
huchten.* The comparative anatomy is dealt with by Hdinger.
A full description, which, however, is not altogether satisfac-
tory, is given by von Kolliker.
Miss Gertrude Stein, wlio is now studying a series of sagittal
sections through this region from the brain of a babe a few weeks
old, describes the nucleus of Darksehewitsch as follows : "Tlie nu-
cleus is more or less conical in shape. It lies dorso-niedial from
tlie red nucleus, being about as thick in a dorso-ventral direction as
is the dorsal capsule of the red nucleus in which it lies. At this
period of medullation the coinniissura posterior cerebri, considered
simply topographically (that is, as a nieduUated fibre-mass without
particular reference to the cour.se of the fibres), appears as a dorso-
ventral bundle, solid in the middle, subdivided dorsally into an
anterior (proximal) portion and a posterior (distal) portion, while
ventrally it expands in the form of a hollow pyramid, which rests
directly upon the nucleus of Darksehewitsch." As to the bundle of
fibres described above as beinpr situated ventral to the nucleus, and
l)assing forward and ventrahvard. Miss Stein in the brain she is
studying can follow the fibres only as far as the fa.sciculus retro-
* van (iohiicliton. A. bo f^atiglion basal. la coTiimissuro post-halx'nulairc,
Ic faisceau loiifjitudiiial postLTimir et les cellulfs iiHHliillairos dor.sak's chi
nevraxe de la Salainandre. Verliaiull. d. anat. Gesellsili.. .b'lia, l$d. xi (1898).
lai
im
■h\
JF'i..
V ^i
'I ^
T'2<3
TllK NKIIVOIJS SYSTKM.
flexus. The lihrcs most vi'iitrally situatod are very complex in
MiTimyciiiciit. f'oi'iiiiiiyji wliii'l in lln' .sul)sliiiicc of llic imclciis i-uIht.
liidt'fd, the nucleus rulx-r is divisible into Iavd parts l>y this wliirl
of lihres — one part anterior and smaller, tiie other part posterior and
much lai'^i'er. In the anterior portion there are only delicate me-
dullated lii)res, and these ai'c directed almost straifjht antero-pos-
teriorly. In the posterior i)art the meihillated fibres are nnjch
coarser in calibre, are arraiiffed in small bundles, are directed diaj,'-
oiially, and ap])ear to correspond to the continuation inside the red
lujcleus of the libres of the bra<"hium conjunctivum and of the
fornuitio reticuhiris. The anterior line libn-s and the po.-,lorior
coai'se libres are separated fi'om one another in the medial part of
the nucleus ruber by the fasciculus retrollexns. In the lateral i)arl
of the nucleus the two areas ajjproach one another, and the peculiar
ditlVrences between the two masses of libres gradually disappear.
Some of the coarse fibres of the posterior i>art of the red nucleus
curve dorsalward to come into relation with the nucleus of Dark-
schowitsch at the point where the ventral bundle above mentioned
orifjinates.
The upward continuations of the fasciculus longitudinalis
nu'dialis, which could ho h)oked upon as heiiig concerned in
the coiuluctioii of sensory impulses toward the soniiBsthetic
area of the cortex, are not at all well understood. ISo far as we
can find in serial sections tln-ough the baby's brain cut in all
three dimensions of space, it is not possible to follow any direct
upward continuations far into the hy])othalaniic region, and if
the fasciculus longitudinalis niedialis is to be rt'garded as one
of the paths mediating sensory impulses on their way to the
cerebral cortex, this path is almost certainly interrupted in the
hypothalamus or thalamus.
[in
il
CIIAPTKU XLIX.
CKXTUIPKTAI- AXONKS IN Til K I'OKMATK) KKTK'l'LA lUa.
Ford's fltiu/ii'iifftKn'/cflii — II()ii('gj,'C'r's hinlen- LrtiiDshi'inilcl-fnrmdtln
Cciitnil paths of viigiil, t,'l()ss()((lmryii)^ciil. iiiul lri>,'eiiiiiiul iu;rvos —
Fiisciuiili IcyiiuMiti coiitralus.
(CI The Formntio Reticularis Alba.
As to the upwiirtl contimiiitioiis of loii<,'itii(liiiiil bundles of
fibres ill tbe foriiiiitio reticuhiris we bjive iilso little iiifortiuition
that is definite. It iuis been shown by von .Moiiakow that, after
extensive defeet in the hemisphere of the dog, degeneration of
Forel's llaubenfusrilccin, and of many other fibres in the for-
niatio reticularis, results. The eliange is that of simple atrophy
rather than of actual degeneration.
It has been observed in human cases as Avell as in experi-
mental animals, «o that there can be but little doubt that many
of these longitudinal bands of the formatio reticularis are con-
nected by means of neurones of a higher order with the cerebral
cortex. Just where the medullated axones of the formatio retic-
ularis end is not certain. But it seems probable that the jilace
may be the hypothalamic region, or the ventral group of nuclei
of the thalamus, and that a new neurone thence sends an axone
out through the internal capsule to the cerebral cortex. It seems
probable that llonegger's hintcri' Ldn(ishii)i(lfJfitrvi(itintt is to
be here included. The bundles described by Ilonegger do not
coincide with the fasciciUus longitudinalis medialis, but include
the longitudinal bands of the formatio reticularis, which go be-
tween the two brachia conjunctiva dorsal to the decussation, and
beyond the red nucleus into the hypothalamic region. They
become mingled with the frontal and medial bundles of the
capsule of white matter which surrounds the red nucleus.
48 727
\v.
1 r •
I
i
i- ■
1 I
I -
If
7S8
TIIK NKltVOl'S SYSTKM.
Not to 1)0 forjjottcii in tliin i'oiiin'cti()!i are tho upcciiil bundlcH
in tho foriniitio roticMiluriH nmdc ii)) of the inodiillatod uxoiioh of
centnil iioiironoH, tho porikuryoiiH of wliich ant Hituatod in th(!
Fl(i. Ilil. Triiiisvcfsc scctiiin tlirinifili IIk' uifdiillii (il(l(iiij;iit;i of !i nirmsc iil
tlic level iiC Ilie nucleus (•(iniuiissiiriilis. i After S. I^iiinon yCajiil, lieitniK
zuui Sludiuiu iler Midullii < )l>l<pnf;iil:i, ete.. liresler. Leipz.. IHitti', S. 47, I'if;.
lii. I .1. UU( lens eoiuuiissuralis ; II. iiuelelis N. Iiypiisjliissi ; (', deeussiiliu
leinuiseiiruin ; I), tiiinsverse seetinn nf 1 ractus siilil;iriu> ; A', eeiilriil piitli fipi'
N. N. I.\: II. cell of iiiicleus eiiinniissuralis ; h. r. terminal tilires of N. vajins
et N. Klussopliarynneus I (/, conmiissure foiMneil liy eollaterals of hypoglossal
nuclei ; ;/. ./. collaterals of scnsiu'y axoiu's of the second order f<iv the nucleus
N. hypo;;lossi.
nwclei torminales of tho X. vagus, the N. glossopharyngeus, the
N. vostibuli, and possibly also the X. trigeminus. It is desirable
that as soon iis possible tliese bundles, which have been localized
by (Jolgi's method (Figs. 4()4 and 4(15), should bo satisfactorily
topogriiphically located in Weigert-I'id prepanitions of the
modullated formatio reticularis.
The fasciculus togmenti centralis {ceutrah' fftnilwubalni) of
the (Germans) may conttiin some centripetal fibres, but the coii-
• vii
U-
(llU)lMMN(i AND CIIAININO TOOKTIIKU Ol' NKl'UoNKS. 72}>
HoiiHiiH of opinion is tliiit its fihrcs arc in tli** nniin iloHcoiidin^.
It JH (Icscribi'il in I'Imptcr li\ III.
,LI
Kid. 4iVS. — .Scctiiiii thriiiiKli the rliiiiiiliciiccpliiilnii liclow tlic ncim iiitiriiiiin
niilicis N. fiiciulis
.M'Icr S. Kmiih'iii y ('a.jiil. HcitniK /.inn Stiidiimi ilcr
.Vlctliillu <))(lniij;Mtii, clc, linslcr. I.cip/... l.siiti, S. 71, Fit;. •,'(». i .1. I'mtiiiitid
reticularis^ t;risra in wliirli the ialiial iiiilral patli la.xoni's nl' ci'iilript'tal
ncurdncs III' llir mcoimI unlcr cciniicrtiil willi tlic N. vcstilmli ' lies; /i, iatiTal
porliiiii III' till' iiiirli'iis N. vi'^tiliiili Npiiialis ; r, iniijial pni'tinii nl' tlii' siiiic ;
7', Inutiis spinalis N. liiKi'niini ; /', cnrpiis icsliriniuf ; «,/(, cells the a.Mincs
of wliicli run to the lateral central vestiliiilar )iatli : «/, cells the axiiiies of
which Kii lateralward ; c. /, a.MHies which I'un tn (he raphe. The letter c
indicates the a.xnnes.
m.
II
I
5. The Upward Continuation of the Fibres of the Brachium Conjanctivom and
the Radiations of the Beu 'acleas*
CHAPTER L.
0\ THK XEriiONES SUPKRIMPOSKI) ri'OX TIIK BRACIIHM COX-
JUNCTIVUM, AXI) TIIK RADIATIONS OF TIIK RKD XUCLEL'S.
Terminal ii)i! nf fibres of brachium conjunctivum — The capsule of the red
nucleus — Study of secondary degenerations — Cerebello-cerebrai paths —
Somu'sthetic area of the cortex.
Wk have seen that the majority of the fihres in the bra-
chiiim eonjuiK'tivum do not extend fartlier cerehralward than
the red nucleus. The majority of the constituent fdjres of each
brachium conjunctivum partly arise but mainly end in the red
nucleus. There is some evidence that a few of them extend
beyond the red nucleus, joininjj the other white fibres situated
on the lateral surface of this body (Fij?. '.Vli).
The study of serial sections throuf^h the brain of the new-
born baby stained by Weigert's method shows medullated fibres
forming a very distinct capsule to the red nucleus. These
fibres are most abundant anterior to the red nucleus and on its
lateral side, although large numbers are also present upon the
dorsal surface of the nucleus. Relatively few medullated fibres
exist ventral to the nucleus at birth, though in the adult more
exist here. Tt is customary to divide the capsule of the red
nucleus, therefore, itito a lateral portion, a frontal portion, a
dorsal portion, and a ventral portion (Fig. '^'^'.i aiKi Fig. :]-U).
The lateral porti(m of the capsule of the red nucleus corre-
sponds to the bundle which Forel designated as BATh, and
re])resents a part at least of Flechsig's IhiuhrustmhhuKj. It is
the bundle d('sciil)ed by von Monakow as lm]U\. As has been
pointed out above, it lies close to the medial surface of the up-
* ffanhpiisfrnlilinuf, Aiisstrn/i/iinr/pn des rothen Kenicn (jf tiie (icnnaiis;
Capnule (III nojiau r(ni(j<\ nKlintionii tie In calotte of the French.
7;J0
(}KOUPI\G AND CnAININ(; TOOKTIIER OF NEriiONES. 73I
wurd continuation of the main portion of the lomniscus, but it
is easily distinguishabk' from this bundle. There are certainly
many cells among these fibres. Anterior to the red nucleus the
fibres of the different portions of its capsule enter into a com-
mon area— the "field II " of Forel. The further continuation
cerebralward is still a mutter of dispute.
Von Monakow's experiments have shown that if a whole
hemisphere be removed two sorts of changes take place in the
fibres now being considered — (1) actual secondary degeneration
and (2) simple atrophy. Tlie total reduction in volume of the
field amounts to about one half after total defect of one hemi-
sphere. Apparently, the part of the cerebral cortex chiefly
concerned, directly or indirectly, with the radiations of the
red nucleus, is the region of the central gyri and the opercu-
lum. It is possible that some of the fibres are connected with
the island and with the anterior portion of the parietal lobe.*
We are not sure how many fibres in Forel's " field II " ascend
(from cell bodies situated in the red nucleus or gray masses
still more inferiorly situated) nor how many descend (from cell
bodies in the basal ganglia or in the cerebral cortex), nor how
many are directly connected with the ( ortex, nor how many are
indirectly connected with it by means of neurones of other
orders. It is probable that fibres pass in both directions be-
tween the region of the red nucleus and the cortex, and it
seems certain that a part of the fibres extend through the
whole distance without interruption. These, in all probability,
are the ones which undergo total absorption after a defect in
the cortex which has existed a long time. They appear to cor-
respond to a part of the dorsal and anterior portions of the
capsule of the red nucleus. On the other hand, a great many
of the ascending fibres, in all probability, end free in the hypo-
thalamic region and in the thalamus (Mingazzini, Dejerine),
and are connected with the cortex, if at all, only by means of
neurones of a higher order. It seems probable that the fibres
forming the lateral and ventral })<)rtions of the capsule of the
red nucleus are here to be considered. Von Monakow sug
gests that the fibres forming the dorsal capsule of the red nu-
ilfp \i
* At least four cases of atrophy of tlic rod niu'lcus after cortical lesions
have been descrilu'd, one by Fledisig and lioesel, one by Mahaini, one by
von Monakow, an<l one by the Dejerines.
\i
}
f
\
732
TflE NPmVOUS SYSTEM.
cleus iiro identical with 1 1 otiejf jeer's kintcn; LangMlnddfor-
vmtion.
An observation by the Dojorines is so important in this
conneetion that it deserves more than passing notice.* 'I'iiey
had the good fortune to obtain fo'- study the nervous system
from a man fifty-three years ohl, who had for eleven years suf-
fered from a right-sided hemiplegia with total aphasia. At
autopsy there was found a very extensive lesion of the (ierebral
cortex involving the whole external face of the left liemisphere
and the orbital surface of the frontal lobe without injury to the
central ganglia. There were multiple secondary degenerations.
There was not only a degeneration of all the projection fibres
of cortical origin, but also a total degeneration of the fibres of
the internal capsule, of the foot of the cerebral peduncle, of
the substantia nigra, and of a portion of the red nucleus.
They were able to follow in this case very exactly tiu' course of
the bundles of fibres wliicli they believed to pass uninterruptedly
between the red nucleus and the cerebral cortex {Jihres cortiro-
ruhriquex dirertes). They could identify them below the de-
generated fibres of the internal capsule in the upper part of the
hypothalamic region, whence the degenerated area extended
inward, passed between the geniculate bodies on tlie one side
and the bundle of Ti'irck on the other, and occupied an irregu-
lar zone outside the central gray substance of the third ventri-
cle — a position which corresponds evidently to the upper part
of the capsule of the red Tiucleus and which is situated between
the fasciculus r(^trofiexus of Meynert and the bundle BATh of
Forel. The degeneration of these fibres, which form a portion
of the radiations of the red nucleus, could be followed into the
whole of the dorsal and anterior portion of the red nucleus.
The ventral and posterior part of the nucleus was normal, as
was also the brachium conjunctivum. Xot all of the dorsal
])art of the red nucleus was deprived of fibres. On its dorsal,
anterior, and lateral surface the thalamic contingent of the
radiations showed undegenerated fibres, and one could in this
case easily decide, therefore, which of the radiati.ms belonged
to the thalamus and which belonged to the cerebral cortex.
i|
* DejcriiitN J., ct Mmc. .1. Dcjoriiie. Siir les connexions dii noyiiii roiiRe
avec la corticiilitt' ctiiebrale. ('ompt. rend. See. dc biol.. Tar., 10. s., t. ii,
(1895), pp. 236-2:50.
•^
'''^1 \ 'i
i-ll PIUHI»-— — -
GROUPING AXI) CHAIXTN'G TOGKTHER OF NKUIIONKS. 7:33
Between the cortex of one cerebellar hemisphere und tluit
of the opposite cerel)riil hemisphere two paths, therefore, in all
probability exist, one consisting of three superimposed neu-
rones, tlie other of four. The neurones of the more direct
path would include (1) a neurone the axone of which extends
from the cerebellar cortex to the nucleus dentatus ; ("-i) a neu-
rone the axone of which extends from the nucleus dentatus
tlirough the brachium conjunctivum and its decussation to the
red nucleus of the opposite side ; (:{) a neurone; with the
axone extending from the red nucleus to the cerebral cortex.
In the less direct path four neurones would be involved: (1) a
neurone with axone extending from the cerebellar cortex to
tlie nucleus dentatus; ("-i) a neurone connecting the nucleus
dentatus with the opposite lucleus by way of the brachium
conjunctivum ; {'.)) a neuro. ojinecting the red nucleus Avith
the hypotludamus or thalamus; (4) a neurone connecting the
hypothalamic region, or the thalamus, with the cerebral cortex.
I would suggest that the term " soniiesthetic area " * be re-
tained for all those regions of the cortex which receive centrip-
etal impressions from these central sensory conduction paths,
be it by way of the lemniscus, by way of the formatio reticu-
laris, by way of the fasciculus longitudinalis medialis, or by
way of the upward continuation of the brachium conjunctivum
and the radiations from the red nucleus, and whether the con-
duction be directly from these bundles, or indirectly by means
of neurones of a higher order interposed.
* h'orperfufilnp/idre of Munk and Flechsig.
tiiHWi?
M,^
^"U
I
i:
i!
r ;
! i
'^
Hi
'I
.'
6. Central Centripetal Axones passing through the Internal Capsule (Corticopetal
Projection Neurones of the General Someesthetic Conduction Path).
CHAPTKR TJ.
Einbryolofjical nioinbormont — Flcchsig's system Xo. T — System Xo. II —
System Xo. Ill — ^('.s«/«c' of soina'sthotic coiidiKdion jtullis.
Fkom wliat has been said in the forejioing chapters, it will
be plain that Ave are in nrgent need of more exact knowledge
concerning the sensory paths from the tegmental portion of
the cerebral peduncle to the cereljral cortex. It is certain that
a large majority of the fibres are interrupted (nearly all of the
lemniscus, prol)ably all of the fibres of tlie fasciculus longitudi-
nalis medialis, many of the fibres of the brachium conjuuctivum,
and radiations of the red nucleus). It seems likely that a part
of the fibres pass directly out to the cortex (possibly a portion
of the lemniscus, many of the fibres from the radiation of the
red nucleus). The stations intercalated in the path are of rather
wide area (ventro-lateral group of nuclei for the thalamus, for
the lemniscus, gray matter of hypothalamic region, of ventro-
lateral portions of the thalamus, and possibly of Luys' body,
and the ccntrr median of Luys for the fibres of the other bun-
dles). Secondary degenerations show a different path through
the internal capsule for different portions of these centripetal
fibres from these various intermediate stations. Thus, while
they all pass through the posterior portion of the pars occipitalis
of the internal capsule, still in this region it is possible to sep-
arate, to a certain extent at least, the area corresponding to the
axones couiing from the intermediate stations connected with
the lemniscus from the areas which correspond to the inter-
mediate stations belonging to the radiations of the red nucleus.
The embryological studies of Flechsig dealing with the
sensory fibres going to the cerebral cortex may be mentioned in
this connection. Flechsig unfortunately does not distinguish
clearly in his work the upward continuations of the lemniscus,
734
aUOUPTXG AND CHAINING TOGETHER OF NEURONES.
185
direct or indirect, from those belonging to tlie radiations of the
red nnclens, etc. lie gronps tlie large mass of centripetal fibres
together, and states that })assing through the internal capsule
the indirect continuations of the sensory fibres of the dorsal
roots of the spinal and cerebral nerves can be divided into three
definite systems, which become medullated at different periods.
He has designated these three systems of fibres, according to
Pica
Fig. 4r>fi. — Siifjittal section tlmmuli tlic Inuiiini lir.iin ; sclicniutic. i After P.
Kleclisif;. Die Ldcalisiitioii der ncistifi' ii Vt)rf;iiii};e, etc., I.,ei))j!., ISilK, S. 14,
Fifj. 1.) 'r/(, };lol)iis i>allitliis iif tlie lenticular mu'lciis ; /', laitanieii : .Vc,
iiiicleiis caiitlatiis ; /.A', lateral nucleus i>f the tlialatniis: .vA', c\i|(-sliaiie<l lindy
of thalamus i srliiih'iifonniurr A'ric/dc) ; cm. cfiilrr iiiiiliini of l,uysof thalaniiis ;
nil, medial nucleus and iiulviiiar; r, anterior nucleus of thalannis; /.A',
SIC. cm. tojjether reiu'cseiit l''lechsi};'s veiilro-lateral fjronp of nuclei of the
thalamus; IIK. r. represent his dorso-medial firouii of nuclei; (•(', internal
capsule; /,. nucleus hyixdlialaniicus i corpus Liiysi); /•'./. superior frontal
fjyriis; /•'.///, inferior iVontal fryiiis; <1II, Kyrus hiiipocanipi ; IT, anterior
central K.vrus ; U<\ jiosterior central n.vrus ; Sli. sulcus centnilis liolandi ;
N.o;), sulcus parieto-occiiiitalis : /•'/.(•((, lissura calcarina j /, /, /, /"', sensory
system No. 1; J /./'...'". sensory system No. '.i ; .),.■;..'{", sensory system
No. H ; diU'erent kiiuls of dottt'il lines are used to represent these three sy.s-
tems in all the (inures. The corticoiictal paths of the optic thalamus are
representeil in the linure ; the corticofuf;al coinluction paths of tlw dorso-
nu'dial firoup of nuclei of the thalamus, the tuoior paths of the cerehral
cortex, etc., are iu(t shown. Tin' ariiinsreiueiil of the points in the ventro-
latenil domain of the thalamus is scheiuatic.
the order of their medullation, as systems I, II, and III (Figs.
4(5G— iOS). For system No. I the myelin appears at about the
I
i
I
t ^
r^
( s
if
■ I
I
rat)
TflB] NKRVOUS SYSTEM.
bo^imiiiijf of tlio niiitli fcptal niontli. It occupios tlio poatorior
part of tlu> intcriiiil capsule, iiiul in its upper half tlio area ini-
niediately beliiiul tlic fibres of the pyraiuidal tract. The iibres
of tliis system ii ' r> main pass up from the basal portions
of the lateral ir of the thalamus, the cup-shaped body
(sr/iitlcn/onnif/cr Ku, ^ r of Flechsig and von Tschisch), and in
part, Flechsij; believes, directly out of the medial lemniscus.
They are distributed exclusively to the cortex of the two cen-
tral gyri, which are thus, the first of all, the regions of the cortex
to become connected by means of medullated fibres with the
GsiTU
Fig. 467. — Frontul st'ctiim tlinmuli the liiiiiiaii brain ; schoinatic. (After P.
Fli'chsiK, Kit" liiicalisationsdcrfji'istiKiMi ViirfiaiiKf. <'tc., Lcipz.. IHitti, .S.ao, Fijj.
2.) /, 11, III. first, sccinid, and third jiortion of tiii' nnclcns Ifiitiforniis ;
l.K. lateral nnclciis of thalannis; i/v. iK! medial nneleiis of thalainns: \c,
nneleus eandatus ; /,, nnelens liypotlialaniiens (eorpns Lnysi ) ; uK. hracliiiun
eiinjunctivnni ; «, tnntns optiens ; . I m, nnelens an\.v};dalii' ; Fs, Fcissi Sylvii ;
lll\ posterior eentnil ^yrus ; (lam, fiyrus snpniiuar>;inalis ; 77. Til. Till,
sni)erior, middle, anil inferior tem|>onil nyri ; V. anterior tninsverse temporal
gyms; oT. fj.vrns oceipito-teniporalis ; /,;<. lobnlns paraeentralis ; liii, eorpus
callosum ; n, anditory eondnetion path.
sensory apparatus of the body. The fibres of this system are
marked 1', 1' in the diagrams.
A few of the fibres of this system, corresponding to the pos-
terior angle of the lenticular nucleus, run in the external cap-
(lUOUPING AND (MIAININO T()(}KT[IKU OF XKUHONKS
•in
suU', and in the most posterior part of the luniiim nieduUuris
lateralis of the lenticular nucleus. A small bundle appears to
Fifi. 468. — Horizontal section throU};li the liuniiin In-.iin ; s<-licinati('. (Al'tfi- I*.
Fici'iisif;, Die liocalisiitioii dcr jicistiK*'" Voi'KiinKt', t'tc, r.fipz., ISSMi, S. 23,
Fifj. li. ) /, //. Ill, first, second, ami third portion of tlic nucleus Icnti-
f(U'iuis; .Vc, nucleus ciiudatus : /.A', latenil nucleus of tlialannis ; il\, nu-clial
nucU'Us of tiialainus; cm, vvutri' iiii'iliini ; I', pulvinar; M, fasciculus retro-
llexus Meynerti in cross section : liC, posteriiu' coniuiissure : Z, pineal body;
/', pyniuiidal tract ; .(, Arnold's bundle of internal capsule ; 7', sensory
rofiioii of internal capsule; ii, auditory conduction iiatli : S(;, (li-itiolet's
radiation ("<)])tic radiation in the wider sense " i ; o, corticofujjal paths of
(tnitiolet's radiation; p. corticoi)etal paths of tJratiolet's ra<liation, projec-
tion tihrcs of the latenil geniculate hody ; ^^, anterior transverse teuiponil
gyrus KoiuK over into the superior temporal gyrus; (r'x, gyrus suhangularis ;
i"'/, superior frontal gyrus; /•'///. inferior frontal gyrus ; (If, gyrus foruicatus;
SC, suhiculuni cornu Ammouis; //. posterior horn of lateral ventricle; Op,
operculum; I'm (dotted), cross section of large association system between
sonursthetic urea (central gyri) and posterior large a.ssitciation centre; ,/,
cortex of island of Keil.
i'
< ■
'in
'Si
'-i
J
I
riJTT
'.[
f '■
ii
II
738
THE NERVOUS SYSTEM.
po into the lower piirt of tlip optic riuliation (1 + ), tlio exact
(listrihutioii of \vlii(!li is not yet ciTtiiin.
The sensory system No. II bejjins to reeeive its myelin about
a month later than does No. 1. The fibres of this system also
pass out of the lateral nucleus of tlie thalamus, but more dor-
sally. A few of them issue from the rctifrr inediait of Luys.
Passiufi; upward, they are distril)ute(l in part to the central j^yri,
the lobuliis paracentralis, and to the foot of the superior frontal
gyrus. Another portion of them, after bending around at an
acute angle and passing inward, becomes distributed to the
gyrus fornicatus along its whole length. Tlu' most posterior
bundles ("-i'. Fig. 4(t()) enter into the <'ingulum and run toward
the Amnion's horn. Still later another bundle belonging to
this system runs from the lateral nucleus of the thalamus basal-
ward and enters into the uncus, and arrives from in front and
below at the subiculum cornu Aninionis. Tlu' whole of tlie
lind)ic lobe thus comes to be connected with the lateral nucleus
of the thalamus.
The sensory system Xo. Ill, the last to become medullated,
is also connected with the lateral nucleus of the thalamus,
emerging from the anterior portion of it. It enters the internal
capsule in about its middle portion, and runs in part directly
to the foot of the third frontal convolution, another part curving
markedly, as shown in the diagram (Fig. 4()(i, ;?, :J"), before reach-
ing the cortex. Buiullcs of the latter run from the region of
the pyramidal tract forward into the fasciculus subcallosus, and
descend at the anterior nuirgin of the corpus striatum to the
third frontal convolution {'X). The fibres of a second group
pass through the pars frontalis of the internal capsule into the
frontal lobe almost as far as the pole, and then bend round at
an acute angle, part of the fibres reaching the middle portion
of the gyrus foniicatus (:i), another part the anterior half of
the superior frontal gyrus, while single fibres go to the foot of
the mi(ldl(> frontal gyrus.
It is of the highest importance, in order that the results of
these researches of Flechsig and those of the study of secondary
degenerations may be satisfactorily interpreted, that studies by
(lolgi's method be undertaken. It is to be hoped that in this
way a more exact analysis of the paths under consideration may
be made, so that ultimately we shall be able to state positively
the exact position of the cell bodies and axones of the neurones
OROriMN(J AND CHAINING T()(}KTI1KH OP NKI'IIONKS.
'31)
hf'loiif^ing to the dilTercnt portions of the cojiiplcx series of
neurone systems which mediate the eentripetal eomhictioii
from the sensory surfuces of the body toward tiie somiesthetic
area of the cerebral cortex.
Let us jiow sumniiirize brieHy the contejits of tlu' dmptera
immediately preceding, l)earinii on the soma'sthetic conduction
path. We have seen that it consists of peripheral centripetal
neurones (centripetal neurones of the first order of the spinal
and cerebral nerves) and central centrij)etal lU'urones (c;eTi-
tripetal neurones of the second order, and of higher orders).
The cell l)odies and periplieral processes of the periplieral
centripetal neurones are situated outside the central nervous
system, while the axones plunge into the nerve centres and ter-
minate in the nuclei terminales of the sensory nerves. In these
nuclei terminales are situated tlie ])erikaryons and dendrites of
the lowermost central centripetal neurones, and their axones
carry the impulses on to higher centres. Posnibly a few axones
of these lowest central centrij)etal neurones go as far as the
somiesthetic area of the cortex, but as a rule, however, they ter-
minate in some gray mass on the way (mainly the thalamus),
there coming into conduction relation with central neurones of
a still higher order, whose axones carry the impulses out to the
somtesthetic area of the cortex. The simplest somoisthetic con-
duction path then would consist of at least two superimposed
neurone systems — one peripheral centripetal neurone and one
central centripetal neurone. In all probability the main som-
jesthetic conduction path, however, consists of three sets of
su])erimposed neurone systems— one peripheral centripetal neu-
rone, one lower central centripetal neurone, and a third higher
central centripetal neurone. In addition, in tlie possible som-
{esthetic conduction paths there are much more complex super-
impositions in the domain of the central neurones, so that from
the periphery to the cortex four, five, six, ten, or perha])s a
great number of neurone systems may be superimposed. This
is especially true of the roundabout sonuesthetic conduction
paths by way of the cerebellum.
The peripheral centripetal neurones have been divided into
(1) those pertaining to the spinal cord and (3) those pertaining
to the rhombencephalon. The central axones of tlie spinal
peripheral centripetal neurones end in their nuclei terminales
in the spinal cord, medulla ()l)longata, and cerebellum. The
1 , ;
I
ill''
74(1
11 IK NHIIVOUS SYSTKM.
Hxonos of llio central cciitrijM'tiil neurones wliosp ])(>rikary<)ns
and (lerulritea correspoiitl t(» (lie nuclei terniiuales of tlu' jK'ri|)li-
t'ful Hpinal eentripetal lu-uronos do not all follow tlio siiTuo
course; on llie contrary, they assunu' in the central iutvouh
system very tlilTerent ascendiiij^ paths, aiul have at times entirely
dilTi'rent terminations; in otlier words, at tlie junction of the
j)erij)lieral spinal centripetal neurones with the neurone systems
of the Hoeond order there occurs a marked t/itrn/i'iirc m iho
Homiwsthetic conduction paths, licavinj? out of account the
terminals of axoiu's and collaterals whi<'h rea<'h the ventral
horns of the spinal cord, we have seen that many axones of
spinal centripetal lu'urones terminate in the nucleus dorsalis,
in the dorsal horn and iniddle part of the {jray matter of the
spijial cord, in the nucli'us funiculi fjracilis, and the nucleus
funiculi cuneati of the nu'<lulla, and some even in the cere-
helium. The axones from the cells in the nucleus dorsalis
asceiul in the i'asciculus spino-cerehellaris dorso-lateralis to enter
the cerebellum by way of the corpus restiforme, and to termi-
nate in the cortex of the worm, ^ivin^ otT collaterals to the
nucleus dentatus as the tihri's ])ass l»y it. The axones of the
central centripetal lu'urones and ])erikaryons, which are situated
in the dorsal horn and in the middle part of the gray matter
of the cord, ascend partly in the wiiite matter of the same
side and partly in the wliite matter of the opposite side in
the fasciculus ventro-lateralis superficialis (lowersi and in the
fasciculus ventralis et lateralis ])roprius. These axoiu's have
various terminations: some, as we have seen, run in (lowers'
tract to the upper part of the pons aiul tlien turn back along-
side of the brachium coiijunctivum into the cere])elluni to end
in the worm, others turn into the cerebellum through the corpus
restiforme, still others terminate in the colliculi of the corpora
(|uadrigemina, others in the substantia nigra, others in the
thalamus, and, finally, some in the nucleus lentiformis. The
fibres of the fasciculus lateralis pro])rius termiiuite in part in
the nuclei laterales of the medulla, in j)art in the formatio
reticularis grisea. Some of these axones are quite long, others
are very short. The axones of the fasciculus ventralis ])roprius
in large part enter the fasciculus longitudinalis medialis, and
come into relation with the motor and sensory nuclei and great
reflex centres of the medulla oblongata.
The axones from the nucleus funiculi gracilis and from
(iHoriMNd AM) CilAININC; TO(iKTI!10Il OF NKUUON'KS.
r4i
the luiclciis funiculi cuiicati, hh wc have seen, corrcspoiKl to at
IcuHt four iicni'diic systems of tiic second order, two of tliciii
{^oiiifl to tiio cerehellum {\, Ki/.s/niifi nii/i/riirfji/ifi/o-ntThf/hnr
cntrinftn/i ; 'i, si/sh'i)i(f i)ii/f/i'/in'/t/i((l()-(i'n'/)r//in'r iioit-criifiiil inii),
two of tlieiu jioin^ directly to the ccrehrinii. Of tiie lalter,oiie
set of axoiu's — the tiiain set — end in the ventro-hitenil ^roiip
of nuclei (»f the ihuhiuwiA (\, si/.slcniii /nun israir mi/rh'/irrh/m/o-
tlitilitniiii(ni). The axones of the other set j.'o all the way out
t(» tlie cortex of the pallium, to terminate. accordiMjf to Tscher-
mak, in the ;;niy matter of the sonnesthetic area {'i, siislniid
letnnisrah' nii/i'/ciiir/i/iii/o-jxi/h'd/inii). (hi their way these axones
to the cerebrum {five olf collaterals to tiie nucleus olivaris in-
ferior, and to the motor and retlex nuclei of the medulla ol>-
lonj^ata, pons, and midbrain. A part of the axones undcr^fo a
lii<fh crossiiif? in the commissura superior of Meynert, in order
to enter the nucleus lentiformis of the opposite side.
Of the axones which pass into the cerebellum, we liave to
consider (1) those which <j:o <lirectly from the spinal cord to the
cerebellum, and {'i) those which go from the nuclei of the me-
diiUa into the cerel)ellum. Among the latter may be classed
certain axones from the nuclei of the dorsal funiculi, the nuclei
funiculi lateralis, and the nucleus olivaris inferior. The axones
on eiiti-ring the cerebellum terminate in the cortex (»f that organ,
and also come into manifold relation by means of c()llaterals
with the nucleus dentatus and adjacent gray masses, proba])ly
of both sides. The fibres from the nucleus olivaris inferior
to the cereltcUum forin the so-called fibra^ olivo-cerel)el lares.
From the regions of the cerel)ellum, in turn, in which the fibres
mentioned terminate, there proceed axones of neurone systems
of a higher order which extend cerebralward — namely, those of
the brachium conjunctivum, most of which terminate in the
nucleus ruber of the op])ositc side, some beyond this nucleus,
some, however, going to the thalamus of the same side. From
the nucleus ruber of each side there go out axones of neurone
systems which extend in the main to the nucleus lentiformis
and to the soma'sthetic area of the (H)rtex. These make up in
large part the "radiations of the nucleus ruber."
F^'rom the ventro-lateral region of the thalamus, in which so
many axones of the central neurones of the soma?sthetic con-
duction path terminate, there extend neurone S3'stems to the
somaesthetic area of the cortex — systems which can be subdi-
ii'iiillPi
•1
•' h
i
ff
1^ i ir
III
mM
1 1
«
742
TIIK NKIIVOI'S SYSTKM.
vi<li!(l into tlii'i'c jfrcut ^rniipK, ucconliiif; to their pcriotl of riiyo-
liriiziilion. (System NO. i, System No. II, mid System No, III.)
The jieriplienil neiirom'H |iei'taiiiiiiji; to tlie rliomljemeplm-
(itcd .oblong
MuscU
Fio. 409. — .Scheiue of gt'ucral souia'stlictic putlis ; lottoriiij; tlio ; inn.' as on pi. i,
FiK. 1.
w
OKOUI'INd AND ClIAININMi To(}KTIIKU OF NKIUONKS. 74^
loM coticTiKMl ill the r(»ii(lm'tii>ii of Ixidily iriii»ulsfs ciiil in tin-
niuU'i tcniiiniilfs of the sensory ccrt'ltnil nerves. 'I'lie uxoncrt,
aH wo have seen, correspond to those of the N. vu^nis, N. <;h»sso-
pharyn^ens, N. vestihnii, and N. tri^'einiiii. The axones of tlie
central nenrones, whiih l)eh)nj,' here, enter partly the leinniseiiH
medialis anti partly the faseienlns lon<^it udiiialis niediidis that
is to say, they run in eotnpany with the prineipal lumdles of
the (UMitripetai axones of the spinal sonnesthetie eonduetion
|iath. For certain of the cerehral sensory nerves, however,
there are especial central hiindles in the forinatio reticidaris
that have been pointed out in their appntjiriate connection.
(Cf. (ieiitral paths for the N. vaj^'us, N. ^dossopharyn^reus, N.
intermedins, X. vestihuli, and X. tri^'eininus.) It is not impos-
sible that some of the cereliral nerves also make roundiibout
conduction ])aths hy way of the cerehellum and hrachium con-
junctivum. From the cerebral peduncle on, it has not been
possible thus far to distinfjuish the central paths of the (cerebral
nerves from those whi(di correspond to the spinal nerves.
These manil'ohl distributions of central axones aiul collater-
als ill the spinal cord and rhondx'iicephalon render possible the
enormous nund)er of con<luctioii relations necessary for tlie
construction of the reflex and instinctive mechanisms wliich
are associated with bodily centrii)Otal impulses. 'IMie axones
whicli reach the so-called soma'sthetic area of the palu.im an;
in turn able to atfecjt associiation neurones which cond)ine the
activities of the sonuBstlieti(; area with those of the other sen-
sory areas of the cortex. In the soma'sthetic area are situated
also tile perikaryons, deiulrites of the motor neurones, the ax-
ones of which extend from the pallium to the {j^roups of jhtI-
karyons bi'lonffin*]; to the lower nujtor lu'urones (motor nuidei
of the midbrain, pons, medulla oblonjijata, aiul spinal cord).
It is thus obvious that the motor conduction paths can be
affected in different parts of their course by way of the various
sets of superimposed neurone systems of the soiuiwsthetic con-
duction path. The lower motor neurones are, by means of col-
laterals at least, in direct conduction relation with the perij)h-
eral centripetal neurones ; the sensory neurones of the second
order come, by means chiefly of collaterals, into conduction
relation with the large lu-rve cells of the formatio reticularis,
the axones of which in turn can affect the lower motor neurones,
while the higher central centripetal somaisthetic neurones can
49
mi
■liilii!^
■f:
I
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I. '
f ! 1 '1!''
sir
ill .il^
I 'y I .•ii
Hi
iii'l
744
THK NKUVOUS SYSTKM.
Fi<i 470 — S<.Kiiic of general .soiiurslhctic paths ; lettering tliesame us lor pi. n.
Kit,'. 1.
U1U)UPIN(J AM) CHAINING TOGETHER OF NEURONES. 745
Gcp
1) CluJi
■ ' 'nuci,c«iiii
Hippoc
Kl(i. -JTl.— Sfhenu- of neurones supcrimiioscii in ncncnil sorniestlictir patlis; Ict-
tiTJUK tlif .sinii' as on pi. i, Fins. 4 and 5.
'v1
riT 1^
f • '
('-
; I
t I ' 1
4(>
i-±i)
THE NERVOUS SYSTEM.
directly, in all probiil)ility, atTect throu<;;li tlio coiuhiction rela-
tions which are estal)li.she(i in the sonuesthetic area the neurones
whose axones form the pyramidal tract. Filially, it seems likely
tiiat from the a.ssociation centres of the cerebral cortex which
are on the one hand thrown under the influence of the .somass-
thetic area as well as under the intluen(!e of the other sense
areas of the cortex, paths may ji;o out to reach the motor areas
of the cortex again, and thence by way of the pyi-amidal tract
affect the "jroups of lower motor neurones. When one regards
the possibilities of communication between sensory neurones
on the one hand and motor neurones on the other hand, actually
thus far established, and thinks of the infinite nuni])er of com-
munications which may yet be demonstrated, the intimate rela-
tions of these sets of neurones with one another becomes truly
astounding.
Particular attention is directed to two great subdivisions of
the somsesthetic conduction paths — J, the paths from the pe-
riphery to the cortex but not passing through the cerebellum,
and Z>, the less direct paths by way oi the cerebellum and brach-
ium conjunctivum. Here anatomical knowledge is vastly in
advance of physiological research and of clinical application,
but we may hope that the ju-ar future has much to reveal con-
cerning the res])ective functions of these different paths.
A scheme illustrating some of the better known neurone
systems of the general seiisory path from the periphery to the
cortex is given in F'lgA. 4(i!», 470, and 471.
w^
(B) Central M'eurones of Sensory Conduction Paths Corresponding
to the Organs of Special Sense.
\Vk have now to pass on to the neurones of the second order
and of higher orders which conduct centripetally in connection
with the paths which .ve to do witii the organs of special
sense — namely, the sense of taste, the sense of smell, tlie sense
of sight, and the sense of hearing. Altliough on superficial
examination these paths are very different from those conduct-
ing to the som.Tstlu'tic region of the cortex, we shall find on
closer examination many analogies.
CHAPTER LII.
CENTRAL NEURONES OK TIIK (iLSTATORY AND OLFACTORY
CONDICTIOX PATHS.
Central gustatory neurones — Central olfactory neurones — Structure of rhin-
enci'[ilialon — Studies of Sir William Turner — Studies of W. His —
Studies of [{et/.ius — liulbus olfactorius — Tractus olfactorius — Stria^
olfactoriiP — Conirnissuni anterior cerebri — Olfactory terminals in the
frontal and temporal lobes — Olfactory association ami reflex paths.
1. Central Neuivnes of the Gustatory Conduction Path.
OiK knowledge of these paths is incomplete and extremely
unsatisfactory. Turner,* in reviewing the subject, finds dis-
agreement among investigators as to the peripheral gustatory
TU'iu'ones and almost complete ign(trance as regards the central
gustatory neurones. For the pathology of taste sensations the
excellent epitome of Frankl-Hochwart f is recommended. The
diagrams on page 528 may also be referred to.
* Turner, W. A. Note on the Course of the Fibres of Taste. Edinb. M. J.,
vol. 1. n. s (1S07). p. 74.
f Article in Xothnaiiers S|)c/,. Path. u. Therap., .Milh. iv, Thcil ii, Md. xi,
Wien, 1897.
747
if
••■1:
''^■'l *■■.
I I
': i
I ■
!(
I;
iiiHii
748 THE NKItV^OUS SYSTKM.
2. Central Neurones of the Olfactory Conduction Path,
Inasmncli us the olfactory cojuhictioii path is the first patli
in the forcbvaiii connected with tiie special sense organs to
become meiluUated in the developing hunuin fu;tus, it may
appropriately be first considered. We have already seen how
theaxonesof the peripheral olfactory neurones terniinate within
the olfactory glomeruli of the olfactory bull). It is now neces-
sary to examine the neurones and their various processes by
means of which these impulses, arriving in the olfactory bulb,
are curried to higher j)arts of the central nervous system.
Before proceeding to this descriptioji, however, it may be help-
ful to refer briefly to the general structure of the olfactory
portion of the bruin.
The more interesting of the earlier studies upon the central
olfactory stations were made by Hrocu,* Schwulbe,f uiul Zuck-
erkandl.J An important advunce wus made when Sir William
Turner ** grovped the regions especially connected with the
sense of smell under the term rhinencephulon, thus distinguish-
ing them shurply from the rest of the forebrain (the pallium),
a distincticm which has been proved by His || to be embryologi-
cully well founded, and by Kdinger to agree with phylogenetic
development.
The size of the rhinencephulon varies enormously in different
* Hroca, P. Ijociilisati iiiscen'briilt's: rt'chcrclios sur Ics centres olfat-tifs.
Kev. (rantlirup., Par., 2. s.. t. ii (187!)), pp. ;5Hr)-4r)r).
t Seliwalbe, G. Lelirbueh der Neurologie, Hvo. Krlaiigen (1881).
t ZiickerkaiKil, K. Das periplioro Gcniclisori,'aii tier Siiiigetliipre, 8vo,
Stuttgart (1887). — Das Uict'libiiiidel des Aiiimunslioriu's. Anat. Aiiz., Jena,
Bd. iii (1888), S. 425-4:54.
* ("f. Turner, Sir \V. The Ton volutions of tlie Iluman Corebruni Topo-
grapiiieally Considered. Kdinb. M. .!., vol. xi (18(ir)-'(KI). pp. 1100-1122, and
especially, The Convolutions of the Brain; A Study in Comparative Anat-
omy. J. Anat. and Physiol.. TiOnd., vol. xxv ( 1 Hl)0-'i) 1 ), pp. lOri-l");?.
II His, W. Die Formentwickelung des nienschlielien Vorderhirns vom
Ende des ersten bis /.urn Beginn (h's dritten Monats. Abhandl. d. math.-
phys. CI. d. k. Siichs. (ieseliseli. d. Wisseiiscli.. Leipz., Md. xv (188!)), S. 67!]-
7.'J6. — Zur allgenieinen Morpliologie des (ieliirns. Areli. f. .\nat. und
Physiol., Anat. Abth., I.eipz. (1892), S. ;M()-38;i.— Ucber die Entwickeliing
des Uiechlappens. Verluindl. d. .\iiat. Ges. (I.SiCi). In this eonnet'tion see
also Minot, C. S. Tlie Olfaelory Lobes, {{ejiort of the Sixty-sixth Meeting
of the British Association for the Advancement of Science at Liverpool in
1896, p. 83(J.
7 "Tfw^.'-'^saic"^
GROUPING AND CHAINING TOGETHER OF NEURONES. 74J)
auimuls, corresponding to the nuirked differences which tliey
exhibit as regards the olfactory sense. Animals were divided
by Hroca into an anosmatic and an osniatic class. The latter
group was further subdivided by Sir Williiini Turner into
iiii( rosniatic and niacrosniatic animals. The rliinencephalon in
niicrosmatic animals is relatively feebly developed, and to tiiis
group human beings belong. The general relations of the
rliinencephalon are accordingly much more easily studied in
lower aninuils than in man, and, as a matter of fact, for a long
time the nature of certain portions of the human brain now
recognized as remnants of the olfactory brain was not at all
understood. In order to gain a clear conception of the relatioTis
of tlie various parts of tlie rliinencephalon to one another and
to the pallium in man it is probably best to study the develop-
ment.
Ills, of Leipzig, has shown that the developing olfactory
brain becomes separated at the beginning of the second month
from the anterior end of the hcniispliere and appears as a pro-
je(!tioii near the lamina terminalis. Between the pallium and
therhinencephalum there is a distinct furrow which Sir William
Turner has designated the Jissnra rhiuira. At a very early
period the rhinein-ejilialon thus marked off is subdivided by an
indentation (the tissura ])riiiia, which is especially marked on
its medial surface) into an anterior half (directed more dorsal-
ward) and a posterior half. The anterior half or anterior
olfactory lobe is in contact with the I'egion which is to be-
come later the frontal lobe ; the posterior half or posterior
olfactory lobe is in contact with what is to be later the tem-
poral lobe (Fig. 47"-i). Al)ove the posterior olfactory lobe the
fossa Sylvii develops. As development ])roceeds, the anterior
olfactory lobe becomes gradually depressed toward the base of
the brain by the growing frontal lobes and it comes finally to
occupy a plane deeper than that in which the posterior olfactory
lobe is situated. Each of the two olfactory lobes consists of a
portion directed toward the base and of a portion directed
medial ward. From the basilar portion of the aiiterior olfactory
lobe are developed the bulbusolfactorius, the tractus olfactorius,
and the trigonum olfactorium, all of which, taken together,
make up what is known as the " lobus olfactorius" of the
anatomists. The basilar ])ortion of the posterior olfac^tory lobe
correspoiuls to the substantia perforata lateralis whitdi is
[I^W
\ Si
y
•I
■■•■
_
750
THK NKHVOl'S SVSTKM.
(It'fiiiitcly (liuriictcrizcd by its j)(»siti()n at tlii' cntmnco to tlio
foHKii Sylvii iind by it.s connect ion witb lh(* ^yriis hi])])()0!iinj»i <»f
the temporal lobe. It becomes in biter (U'vebt|)inent overarched
■■, /
l''l(j. 17^ — Scliciiic slmwiiif; llic iilalidiis iil' tlic Miilciidf :iii<l pcislcriur (ilfiictnry
l<il)('s til itiic aiKilliiT and to the lnlics cif the ccicltral liciiiis|(li(r<' in (lillfrciit
stajics of (lcv<lc«|iin<'nt. AllcrW. His. Die analnniisclii' Ncinicnilalur, dr.,
I.cip/,.. lH!l,"i, S. 177. l''iK. ^'7.1 r. A'. Icilms idtaclniins anliTinr : li.H. lolins
tiHactin'ins pipstcrior ; /•'. legion of liil>iis I'mnlaiis : /', region iif iiilais pari-
ctalis: (). rctiion of lolins (iccipitalis ; '/'. region <it' Inlius ti inporalis ; St,
(■(ii'pns sti'ialnni.
sec(m(larily by the })oU' of tlie temporal h>be. Medialwanl the
substantia perforata hiteralis is (continuous with the gyrus siib-
callosus (medial ])ortion of the posterior olfa(!tory lobe), which
ill the adult human brain is a somewhat indefinite structure,
although ill the iiiiinan fietiis it is a very well-marked morjiho-
logical entity. The gyrus subcallosus (pedunculus coriioris
callosi) is in front separated from the medial portion of the
anterior olfactory lobe (area parolfactoria lirocie) by a dee]) in-
dentation, the so-called sulcus ])arolfactorius posterior (the
fissura ])rima of the eniliryo). The furrow which sejiarates
Hroca's fiel from the beginning of the gyrus cinguli and which
accordingly is situated in front of the trigomim olfactoriuni
and of the area of Hroca has been called by His the sulcus par-
olfactorius anterior. In the adult the junction of the substantia
perforata lati'ralis with the island of Reil is not very definitely
limited, but in the human f(etus at about the fourth month this
junction is sharjily marked off by an arched ridge,* which con-
* Hi'oea's le bunt falcifurme du lobe limbiqiie, Sfliwalbc's IntsehchweUe..
im
OUOLIMNG AM) ClIAlMNCi TOUKTIIEIt OF NKl'ltONKS. 751
nocts the untcrior olfiu^tory lobe with the temporal lobe. The
rcj^'ion, therefore, known us the /iiiii'ii 'nisnhr in the adult is to he
considered as a part of the rhinencepiialon. 'i'he foil o\vin<f table
shows at a fjlaiuie the various ])arts of the rhineneephalou us
de8(!ril)e(l by llis :
RlllNKSi KI'IIAI.ON AcroRDlNCi To Ills.
i I>iill)us olfactorius.
. '*"••« I'asilaris . . 'Pnictiis nlfiicldrius.
. 'i'rif^oiiiim olfiiclnriiim.
■ I'ars im-dialis . j Stria iiiodialis.
/ Area paripiracldi'iad^rocM').
(i I'ars liasilnris = Siilislaiiliaiicrl'ofataaiilL'rior,
( I'ars iiicilialis — (ivnis sulM^ttllosiis.
Lobus olfactorius anterior
Ijoliiis olfactorius posterior
The anterior olfactory lobe is connected with tlie posterior
Ity means of the stria olfactoria lateralis and the lime!i insula'.
The best recent microscopic study of the structures bclonj:-
to the rhineiuH'phalon is that of lietzius, of Stockholm.'' He
calls the area parolfactoria of Hroca the gyrus olfactorius niedi-
I
Fk(. 473. — TIh' hasal surface of a liiiniiui I'o'tus '.i;]..') ciu. loufr (Ix'fjiuniuK nC lifili
inonllii to illiistrati' ilcvclnpiiiK rliiiicncriilialdn. (After (i. I{elzius, I)ms
Meiiselienliirii, Stipeklioliii. Is'HI, 'I'af, wxii, V\<i. 'i. • The traclus nlfaelorii
are (leveidpiiij; : tlie K.vri ulliieliprii iiiedialis are distiuetly visilile ; lliejjyri
oll'acliirii laterales run laleralwanl, lurii at an aiiirle. and kk over inln the
K.vri seinilunares and the tjyri anihientes. Tlie lissnra iliiuiea se|iaratinjr the
rlliueuee))halciu from tlie hihus leniiporajis is distinctly developed ; besides,
otie can see the triangular area lerniinalis and the eniinentia saeenlaris
;id out with its lateral winjis in front of the corpora uianitnillaria, the lat-
x'iuK as yet hut little ileveloped.
siu'ei
ter 1
alls, while he designates as gyrus olfactorius lateralis the region
corres])0!iding to the course of the lateral oHactory stria and
* Retzius, 0. Das Menseliciiliirii. Stockholm, 1896.
m .m
75-2
TIIK NKIlVors SYSTKM.
the linion insula' ( Fif?s. 47:5, 474, and 475). The latorul olfactory
gyrus, (liro(;tc'(l at lirst laterally aiul posteriorly, makes u sharp
turn backwiinl at the tni;/ii/iis lalmilis and goes over into the
anterior extremity of the f^yrus hippocampi, where it fornih two
minute convolutions wiiich Ketzius calUi i\w gyrus semilunaris
%
Vll
VUi. 171. — Part of tlif l)iisil surt'iicc of tlic liraiii of the left li('inisi)lifr(>i of ii
mail forly-tlircc years old. seen froiii Iwlow and to the ri^lit. ' After U.
lielziiis. Das Meiiselieiihirn. Stoekliolin. IsiMi, 'I'af. x.\.\ii, I'Mj;. 5. ) On looking
at the triKotiiiiii olfaetoriiini one sees the two liinhs running; out into the
<,'yriis olfaetorius ini'dialisand the fiynis olfaetorins hiteralisand lieliin<l them
tlie somewliat linlfjinf; sn)>stanlia perfonita aiiteri<ir, on the posterior liorder
of \vhi(di the diajronal hand of Hroea passing: liaekward and hiterahvard from
tlie fiyriis snhcailosiis is distiiietly visihh'. In the jj.vrus l)ehiii(l tlie siih-
staiitia perforata anterior — /. c. in tlie Kyriis olfattoriiis lat<'ralis which is
here separated from the j;yrns tiiiiisversus iiisiihe — can he .seen the white
stria (dfactoria lateralis running; hiterahvard and haekward as far as tlie
iH'^inninf; of tli<' K.vrus hippcpcaiiipi. wlu-re it disappears: the stria olfactoria
meilialis iiliiiifies deep into the snhslantia perforata anterior. On tli<'>;yrus
hippoeaiiipi can he reeo<;iii/,ed iiiedialward an oval, half-inoon-shaped hiil;;-
iiiK, the Kyrns semilunaris, wliiih is separated h.v the sukus seinianniilaris
from the j;.vriis amhiens, more laterall.v placed.
rhineneopliiili iiiid tin yrus ambiens rhineneephidi, the two
being separated from one another by a shallow furrow — the so-
called sulcus semiluiiiiris. The gyrus ambiens in turn is sepa-
rated from the rest of the "yrus hippociimpi by what Retzius
calls the sulcus rhinence|...ali inferior (Figs. 47<i aiul 477).
That these two gyri exist in the region of the uncus, and are
Ciisily separable from it, I can eouHrm from the examination
(;K(>riMN(i ANI> CHAINING T()(}KTI1KU OF NKUllONKS. 7r,;{
of ii imiiibcr of licmisjilHTos in this laboratory, luul it would
seom very probable that the temporal olfactory area, described
I''l(i. 475. — lUustriitiiiu of i)iirt nf the rliint'iicciilialciii it( a iiiiiii forty-tlircc yciirs
old. (After (i. Ivct/.iiis. Das Mtiisclicuhini, Slncklioliii, l«iM), 'I'af. xxxii,
Fij;. H. ) The tniclus cilfaitDi'ii, willi lluir suiroiiiidinKs, and the uyi'i nlfac-
tnrii nii'dialfs el latciali'S Knin^ l>a<k\vanl finiu tluiii, arr well seen. The
nyri olfactdi'ii lalcralfs arc (iistiiictly scparaldc mi cacli side fnnii the ny"'**
traiisvcrsiis insula'. lOacli lateral iilfaetory Kynis eiditaiiis a well-marked
stria iilfaeturia lateralis. In this instance a well-marked stria intermedia is
visil)l<' iiliinsinK into the mnch-hulncd sulistantia perforata anterior. The two
olfactory tracts dill'er in length and anteriorly si)read out into the l)ulhi
ulfactorii.
I
I'"i<i. I7(i. — The hiwer part of the ?.'ynis hipjiocampi. with surroundinn structuro.s
from tlu' rifiht cerehral hemisphere of a fietu^ :is cm. Ioiik. The end of tin^
(lyrus hippocampi hends around the anterior extremity of the lissiira hippo-
campi into the uncus, and the Kvrns intralimhicus sits like a cap upon tlin
end of the uiuils; the border oi' the latter corresponds to the limhiis (iia-
comini ; ahove and anteriorly the ji.vrus intralimhiius is coulinuous with the
hillocklike c.vrus semilunaris • si : on the left the velum lerniinale jjoes
over into the elnu-ioidal layer; lieneath this the fornix and the fa.scia den-
tilta. ( After (i. Het/.ius, Das Menscheiihirn, Stockholm, IMiltJ, p|. I, Fix. :{.)
by Flechsig tind other tmatoini.'^ts as existing in the uncus, has
in reality much less to do with the uncus itself than has been
%
t-
**-•»
"lltf'l
li
754
TIIK NKIIVOUS SYSTEM.
thou|;ht, and really concerns these two small jjyri wliicli, curi-
ously enough, before Ketzius's description apj)ear to have hccn
entirely overlooked.
F'm. 477. — Tlic iiitVriipr iintcrior cNtrcinity iil' tlic };yrus lii|i|iii<'Miii|ii rrniii (Im
hraiii of ii liriy-iiiiic-yciir-old wnniiiii, sicn fidiii iiliovc. lAI'lcr (i. Kt'txiiis,
Das M<>iiscli(iiliini. SidcklKpliii, IHiMi, Tal'. 1, Via. ~:i. ) One rccdniii/.cs tlic
triaiiKtilar cri'scciitic nynis Miiiiliiiiaris ish. whiili is sfparatiMl liy a ciifvcd
I'lirniw : the sulcus scniiauuulaiis (in the fniicaN ily of wliicli a uiiilule is
visilili" tViiiu till' };yi'us auil)irns ' ir ) l>i'u<liu^' arnuiid llic uiirus. Miliiuil (lie
micus. sliarply inarkcd ntV. is the liuiluis (iiacotnini. wliicli t;<i''S(ivcr nirdially
anil lii'liiuil intii tlii' iiiislcridr liudi iit' tlic ;;yi'us sciiiiliiuaris and is separated
piistcriorly liy a siiallnw fiirniw IViim the jiyriis iiilraliiiiliicus. Medial fniiu
ill is ^yrus is attaelied a pdi'timi of the fiiiiliria. and medial from this a^aiii is
situated the lamella of the plexus chorioideiis perforated hy vesstds aloiiK
with the velum, liy means of these structures the cavity of the coriiii infcriiLs
is clo.sed.
Tlic various psirts of the rhincnceplialon described by Ret-
zius arc here presented in tabular form :
CLASSIFK ATION AlCOKDINCi TO HeTZIUS.
1. BulhiiK olfncforiufi.
2. Tructus olf actor ius.
r Stria (ilfaetoria lateralis to gyms
3. TriyaitioH nlftictdriutn (gyrus tuberis | olfaetorius liitcralis.
oifactorii) I Stria olfactoria mcdialis to gyrus
'^ olfactoriiis modialis.
4. Gyrus olfnrforiu.s meiUaUs ^\,.,.,^ parolfactoria Mroca-.
Pars autorior = ]''.bcr.stull(>r's gyrus
transversiis insula' and the liinen
insula'.
Pars jiostorior. Kxlenils from an-
gulus lateralis to anterior ex-
troinity of gyrus hipjiocairipi
and lorniinates in tho gyrus
setniluiiaris rhinencephali and
the gyrus ambieus.
5. Oyrus ol factor his lateralis.
(illOlIMNO AND (•nAIN'lN(J TOOHTIIKU Ol' XKIUONKS. 755
(i. (hirun iin-ftintlux (xen iii/erimdiiiK) \ AiiliTior, iiuicli pcrfonitcil, part
rfiuifnff/ifitili ' of .siibsliinliu pcrfonitii iiiitcrior.
I'o.slcrior, It'ss |i('i'fiirul('(l, [niri of
siilistuiiliii |i('i'rorutii luilci'ior.
Corri-Hpoiulfl to tli(^ iliui^otial
Imml of Mrocii, which oxtcruis
from thi> Ky''"* siihcallosus to
Hiitrrior end of gyrus hippo-
fiiiii[>i.
fji/nis (lidi/iiiiiilis rhiiii'itrcii/ui/i
8. Other /jor/ioiis tif r/iiiii'inip/iiilon,
(ii) (hjruH hippocampi,
(ti) VncHs.
((') (iijruH denlaltiH.
(il) (hjruH intrnUmhicHit.
(i-) (iyntf< /(iseiolarin.
(f) <ii/ri Aiidri'd' lii'/^ii.
ig) Jiulusinm grinvum {incliidiiif,' tlii" ,i////r hmgitudinnlis ntedialiH et
Utii'ralls).
(h) (liiri ,sii/ic<illoni.
Tlic biilhus olfiU'torius (aiitorior oxtrcniity of tli(> lohua
olfiictorius iiiiterior of His) Ls rolativoly imicli smaller in man
than it is in animals like tlu' dog or tlu> rabbit. In the embryo
there is a central cavity in the olfactory bulb continuous
throu<fii the olfactory l()])e with the anterior horn of the lateral
ventricle, but in the adult human l)ein<f this cavity is obliter-
ated, though its site is evid 'ut in coronal sections, being marked
by the presen(!e of a central gelatinous substan(;e.
Since the rabbit's olfa(^tory bulb has been very carefully
studied, this will be described first, and the human bulb com-
pared with it.
7V/f' Min'n Ilitlh in the Ra/ihi/.* — X'on Kollikerf describes the
rabbit's olfactory bulb as being made up of the following layers :
(1) Layer of olfactory nerve fibres.
(2) Stratum glomer ilorum, containing the glomeruli olfac-
torii.
(3) Stratum griseuni.
(a) Stratum moleculare sen gclatinosum, containing
small and large nerve cells.
(b) Layer of mitral cells.
* The rabbit, mouse, and cat possess, in addition to a main olfactory ijulb,
an accessory bulb which lies on the dorso-medial surface of the posterior end
of the main bulb (von Guddeii, von KiJlliker).
t von Kulliker. Op. ciL, S. 693.
I
I
I • I
m
1M
TIIK NKRVOIS SYSTKM.
(4) U'hito Hiihstanco, or prainilc layer, rnntaiiiiiif.' mcdul-
lati'd lUTve fibres and larj,'e iiuriiberH of ininutu luirve
<Hdlw, the Ho-call "olfactory f^ramileH."
These layers are well illustrated in Fig. 47H, taken from von
Kiilliker's book.
""Skm y''-'^^^>.
'/'^-<L ^
/
'*^,
J
>-A/2
Ttom
^*, j<:^--
Fo
Fig. 478.— Fnmtal section o'
sUiin. < After A. vmi K'"'
ii, Leip/... IHiMi, S. (H
^r7((. ;;l()iiienili oil"
Sir iir. stnitimi ji\
s (iH'aetiiriiis uf a yoiiiiK ralil)it ; Weifiert.
.idlmcli (ler()<'we))elelire(les Menselieii, Hd.
Co, eoiimiissiir.il tibri's ; /•'«, (ila olfaetiiria
., iiiitral cells; A7>, accessory lailliiis <ilt'act(H'iiis
; Sfr.ui. str.ituin moleculare ; Tr.o.l, ti-.ictiis oltac
toriiis lateralis; . (''actiis olt'actoriiis niedialis; I7<. veiitriculus liiilhi
ollactorii ; (jr.S, siihsniilia jjrisea.
Inside the layer of granules mixed with white fibres are
accumulated the main bundles of medullated axones, those cor-
responding to the stria olfactoria lateralis (Tr. o. 1., Fig. 478)
and the stria olfactoria medialis (Tr. o. m., Fig. 478) being more
superficially situated than the fibres which form the bundle
OROl'IMNl} AND ClIAlNINC} T(KiKTIlKU <IK NKl'ltoNKS. 757
(ni, Fi^. 4TS) wliich ^och to tlir iititcrior (Miniiiiissurc. Tlic iij)-
j)ounuic«'s of tilt' huiiiim olfiictory liiilb are wt'll shown in fron-
tal section in Fij?. 47!» and in horizontal section in Fij». 4N().
The natnre of the different parts are suflicicntly well indicated
in the le^^ends accompanying the figures, and further deacTip-
tion here is unnecessary.
The olfactory glomeruli receive, besides the terminals of the
axones of the olfactory nerves, extremely numerous, much
branched dendrites from the mitral cells and from the brush
<7/
Tro
M/.
: I
/
>rtb
!
wFb
^
'\',
/
' ■'■■'.■f'-rSf'iiTr''''
' '1 ^ ■
ynr 5
Kr.
Fid. -ITlt. — Triiiisvcrsf scttiim of tlic limnaii t)iill)iis nlfiictorius : WciKirt stiiin.
i.M'tcr A. villi KclUikcr, IliiiKllnicli dcr ( iiwilicltlirc, Mil. ii. Lcip/., IHSW. S.
ii!)H, Fif;. "i)!. ) /•'". tilii iiltUctDiiii ; '.V, nlomcnili (iH'iictnrii ; A';, jiraiiulr layor ;
.V, nioli'i'iilar layer; M'/.. mitral cells; (^(■S, dursal white layer cut trans-
versely; I/O', inner }ii"iiy iiiK'leiis ; riiS, ventral wliit<' layer cut tr.msversi'ly ;
II' /•'/), liuiidle of white (ilires.
;
T
cells of the olfactory ])ulb. It is these dendrites of the niitnd
cells (Fig. 481) and of the brush cells (Fig. 4S-^) which take up
the impulses from the peripherid olfactory neurones and carry
them farther. The peri})heral sensory neurones do not come
into contact directly with the cell bodies of the mitnil cells, but
can affect these and their axones only through the interniediiition
of the dendrites. The axones of the >»'n. olfactorii are easily dis-
tinguishiible from the dendrites of the mitral cells in sections
which demonstrate the neurosomes, since the latter are much
more numerous in the axones than in the dendrites ( Fig. 4H;}).
The axones of the mitral cells and of the brush cells tire medul-
lated and run backward in the trtictus olfactorius toward the
main mass of the brain. On assuming a longitudinal direction
they give off a number of collaterals to the stratum molecuhire.
?1
y
I:
758
TIIK NKKV'OUS SYSTHM.
Tlicso fibres ('an he divided into two sets in tlic olfactory tract
of human beings — a siiiterlicial set consisting ol' tlio libroa wliicli
Fio. 4S(). — llori/ontal section tlinniirli tlic l>iillms and tractns oiractniins of man ;
Wcifit'i't's stain, i After A. von Kollil;er, llandlineli <ier (iewelieleliie, lid. ii,
Liip/... IS'lti, S, (i!l!l. Ki^. 7.");.'. I Itii. Iinilms oll'aetorius ; S. slineture reseni-
blint; siei)tnni; VV.o, tractns olfactorins ; ijrS, islaiuls of {{fay substance;
vHii'S, anterior liiimlle of wliili' siilistance.
lator form the hitertil and tnedial olfactory stripj, and a deep
set consisting of fibres which run into the anterior part of the
anterior commissure of the cerebrum (Kig. 4S4). The relatiotis
of the mitnil cells and l)rush cells to the individiuil olfactory
glomi'ruli vary in ditl'erent animals. Thus, in the cat iind rab-
bit eacli glomerulus receives only one dendrite from a single
U
fwi
I man :
;<\. ii.
the
Lions
ttory
iib-
(JlfOlIMNd AN'D CIIAININO 'IcMSKTllKU OV NKl'HONKS.
rr.i)
initral cell, while in tlic ddi; one j^lomci'ulus may receive dcii-
(Irites rroiii as many as live or six mitral cells. 'I'lie nature of
till' olfactory ;^M'aniiles ( l-'ij,'. 4Srt) is as yet imt well iiiulerstood.
'I'lie lil)res destined for the commissure as they pass Imck-
ward occupy the dorsal part of the tract and ;iradually collect
into a hundle which is rountl in cross section and which enters
directly into the anterior commissure formini: il^ pars ante-
rior. 'I'he lihres of the stria olfactoria lateralis, which includes
tlic niiiin mass of olfactory lihres (Kij^. 4S(t), pass hack ward
I'li;. ISI. — Mitral cflls t'nmi a nioiisc twciit.v-Coiir days did. McIIkhI ul'ddlf-i.
lAI'IcrA. VKii KcillilviT, llaiidlnicli dir ( icwclMliJirc, ltd. ii, Lcip/., IsiMi. S.
"01. t'iji. 7.'>l>. ) />. di'iidiilcs 111' mitral crlU wliicli I'unii a Imi'i/.diilal la.viT ;
.1/, dc(|) milral cilU; .1/-. MiiHilicial milial cilU ; ii. axinics; ///(, dllinlipry
ln'Usli.
and outward lirst on the lateral side of the substantia jicr-
forata anterior, and then backward and inedialward (cor-
respondin<f to the posterior part of the jfyrus olfactorius lat-
eralis), to termimite api)areiitly exclusively in the molecular
layer, maiidy in the <'ortex of the uncus (l-'lcchsitr's /nii/iDriile
liicrlixphiirv). Aceordinjj; to !'leehsi<;, the portion of the uncus
in whicli the olfactory fibres termiiuite has a ])eeuliar structure
in that just beiu'ath the uppermost layer (p(M»r in cells) there
exist.s a layer of ^ <,n'aiiules " (Kiirner) which ajijrees entirely in
50
'I-;'.
n '
ii
11^
liifiiii
760
TIIK NKKVOUS SYSTEM.
structure with tlic nuclear layer of Auirnon's horn, and indeed
is continiidus witli it. As above mentioned, we iruiy have to
Km. 48!i.— Jiulliu.s <iltiicti)rius of ii nioiise twi'iity-fVmr ilay.s ol<l. .Method of Golgi.
(AfUT.V. von Kollikcr, Hiiiidhiicli dcr (Jcwclu'lclirc, l?d. ii. Lcipz., 18im. S.
7(17, Kin. 7r)S. ) (\ collatcriils : (II, nloiiitTiili ; .V, initiiil cflls; M', .siiiterlicial
large bniisli ('('ll ; .U'. siiiiill linisli (('Ii ; /i'/>, olfiu'tory hnisli ; ii. axoiie.
deal here with the gyrus semilunaris and the gyrus ambiens
rather than with the uncus proper. On tlieir way to the uncus
the olfactory fibres give off large numbers of collaterals to the
double pyramidal cells which are situated in the adjacent gray
matter of the rhinencephalon, each fibre thus entering into
relations with a cerebral zone of considerable extent.
Of the fibres which run toward the stria medialis many ter-
Wi.
iJHIm m'li'
GU(iriMN<i AN'l) ('1IAIMN(J TOtlKTllKll OF NEUKOXKS. 7«;i
niinate in tlio gniy niattor of tho trigomiin olfactorium (Cal-
]('ja).* In the gray matter of tliis region the oerebral struc-
ture is nun li modified ; here are situated the curious " olfaetory
ishmds " which wei'e seen by (Janser hut were first carefully
descril)ed by Calleja (i.sloff.s o/fii/iros) (Fig. 4S7). Each island,
consisting of a mass of ])yramidal cells (closely crowded to-
Fi«. Ih:}. — A ^jloiiKTulus (ilfactorius fnmi a ydiiii}; cat ; nictlioil (if (lolfji. ( Aftor
A. vein Ki'illikcr, lla)ull)ii<'li dcr (icwclH^lilirc ilts Mciisclicii. lid. ii. I.ciji/,.,
IMlMi. S. 7(11, V\n. "I'lii. /•>), tila iilliKloria IjrcakiiiK uji into tciiiiiiial luanclics
'!isi(1«' tlic (rlimici'ulus : re, capillary lilodd-vcsscls.
gether and distorted in .shaju'), receives a hirge number of fibres
which break up into an extremely rich end-plexus among the
ill
* Calleja, ('. La I{cj;i(.ii ..Jlatoria del ci'ivbro. Mndrid. IMICV
•\
III
7(>2
Till-: NKKVOUS SYSTlOr.
<H>lls ( Kig. 4N.S). Sonic lihres from tlic nicdiiil olfactory stria
reach the J?yrii8 subcallosus ami the ])arial l)c>jfiimiiijjf piece of
the {?yrus foriiic^atus whicli possesses a special structure cliarac-
terized l)y the presence of only one ^iinj.',lioii cell layer (mostly
spindle cells). Others positively reach the septum pcllucidum
and go by way of the fornix to Ammon's horn. TIk* majority
w^'J^'- j^ysiftLv '^i>r^
SaS
Vu{. ISl. — IJulliiis ct liibiis oHactdfius (if a nilibit in liorizontal sccticm ; Wi'iKcrt's
slain. (After A. von ICiiUikir, Ilandhiicli dcr OcwcImIiIiic, !?(!. ii, IsiHi, S.
()!•", I'Mj?. 7'>0. 1 /{(I, l)ullnis (lifacliiriiis ; f Vi, cDinniissiira aiitcriiir ii rcliri ; /■'»,
fiia oifaftiii'ia ; '.Vo, nldincnili olfactnrii ; /.o, lolms nlfactoriiis ; .U, ni((l('<'ulMr
layiT; .1//, iiiitral rclis ; AV, nucleus canilalns: So', substantia allia sepli ;
>■;), septum iiellueidiiin : Sir i\t\ stratum Kiannlnsum ; 7V. », traetns olfne-
liu-ins lateralis; 17), ventrieulus l)ullii ; Vli, lonni aiiterius of the lateral
ventricle.
I
u
of the fibres of the stria mcilialis tire connected with the tireii
jKirolfactoria of liroca. Thence, by means of jieurones of a
(}ROUlMN(i AND ClIAININO TOCJKTIIKII OF NHUliONES. 7»;3
Fid. 48"). — Tlini' (plf;irtcir.v unuiiilis rnmi a <;tt ; inctlind nf (iiil-ji. The ciintours
of two t'liiiufi'iili anil cil' several lar^e initial cells are iiidicaled. i.M'ter A.
voii Kfilliker. llandlmeli der (iewelielelire, Md. ii. l.,ei|)z., iHitIi, S. 7I;{ Fie.
7(ia. )
n
m
1:
'«
i!fi;l
m
W\
7«5+
TIIK NKIfVol'S SVSTKM.
Iii<,'li('r onltT, coiincctidiis witli I lie iiKlusciiiii ;;ris('iiiii, striat
liillicisi, etc., iirt' |tr(ilt;il»ly t'oriiKMl.
'riic lilfrcs 111" 111*' iiMtcrior I'ltiiiiiiissiin', ?iiiirli less (lcv('l<>|>('il
ill iiinii tliiiii ill iiiMiiy iiiiiiiiiiis, niter llic liciid oi'llic miclciis
(•jiii<l;il us, Itrc'ikiiitr up iiilu I wo groups, ;iii iiiitcridi' set of (ihrcs
niiiiiiii^ (<> lilt' olt'iiclnry Imll) of I lie oppusilc side, I In- pd.sto-
riur, iiiorc iimiicrous, niiiiiiiin' to tcniiiiiiilf in llicuvnis liippn-
(';iiii|)i ( iMJiiincr).
It is cviili'iit, tlicrcforc, tliiit- llic iixoiics of tlic iiiitnil cells
;ili(l ol'tlie iinisli cells (olfjietdry sensory liciiroiies ol'tlie see-
oiiil order), ;is rcpirds tlieir tciiiiiiiiils, jire widely ilistrilmlcd.
They end in dill'erciil piirts ol' the rliiiieiicepliiiloii of the sjiiiu!
side, :iiid l>y ineiins ol" t Ik^ jinlcrior coiniiiissiire in the rhiiieii-
cepliiilon of the o|»posile side. I'"iirlher, the Viirioiis [cirts of llie
rhiiiencephalon iire eomiected iiiiinifoldly with one another,
Fl(i. lS(i.--V('iilnil pari di" a frontal scctinii nf a nil)lii('s liraiii. (Alter A. viiii
Kolliivcr. Ilaiiilliiuli ilcr (irwilMlilirc, lid. ii, Lcip/., |S<»i. S. ~-i:l. Fifj. 7li7J
/>;;, liasil sMiiKliiiii ; Cu, ciiiniiiissuia antcricir: ('i\ capsiila externa; '7".
coininna tornieis; (V, eapsnia interna; AV. nnclens eaiidatiis; A7, iineleiis
lenlilnrnii^ ; /'.v, ennnnissiira liiiiixirainpi ; >/). lilires tViiin seplnni pellui'iduni ;
Stil, stria terniinalis : Strt\ port inn of stria wliieli ^oes to />'(;; >7//'J. portion
of stria to anterior eoinniissnre ; VVo/. tractns oifaetoriiis lateralis; 17, veii-
triciihis lateialis.
and with otiier parts of the brain. When tho neurones in the
gray masses in tiic tnietus olfaetorius, tho trigoiuun olfu(!toriuni,
tjr. ';
^
(iKoriMNd ANI> rilAININd T(»<M';TIII-;K ok NKritoNKS.
,»;.,
tlic iiiTu paroll'iicloriji ( Hroni'), (lie siil)stiiiit iii iMTl'dnitii iintt!-
rinr, the <'vnis oirucloriiiH latcriilis, cti'., arc coiisidcrcMl in all
Fui. \X7. — Isliiiiilsiil' pyiMiniiliil (ills i?i llir (iilii ri'iiluiri iiHiicliitimii nl' liii' iiililiil ;
liii'lliiiil III' (iiil^i. ( AI'ttT ( '. ('MllrJM, \.;\ rr;{iiiii iillUtol'iii ilil ii riliiii. .M:iilriil,
|.H<i:{, p. I!), I''ii;. (i. I .1, cxIi'I'iimI ninlrriihir hiycr ; //, isluiiils nl' |i.vi'Miiiiihil
ci'lls; />, iicrvi^ lilii'cs niiiiiini.' in In iiiil in tlnsi' islMnils ; d, I'liNii'onii rrll
Willi jiscciiilinK iiN'oii'' ; '<. riisiruriii nil willi ilisiriiilinK iixniif ; c, iixoucn of
vai'iinis (ills ; c, rnsifuirn nils uf iiinli riihir liiycr.
parts of wliicli axoiics of iiciiroiics of the Kcfoiid order apprar
to t('nninat(\ the cnorinoiis luiiiihcr of olfat-tory neurones of
the third im<i of liij^lier orders may b(! vaffticly apprecuatc^d.
Some interest iiij,' conniu'tioiis of tliese ])ortioTis of the rhi-
noii('e])halon with other parts of the l)rain have already been
niiidi^ out, thouffli we are far from the possession of any ad(!-
((luite or (exhaustive knowled^fe of all the relations which exist.
Thus there are manifold connections })etw(!en tiie uncus (or
perhaps the jryrus semiannularis and j,'yrus and)iens, rif/r siiprti)
aiul the hippocampus (ruriiK iinnnoitis) {it/f'ni, l'"i<r. AHU). The
lUKileus ainyfjfdala' (louhtl(^ss receives similar fibres. While there
is no doubt about the intimate union of the hi|)pocainpus with the
olfuctory paths, thten; is still dispute as to whether the former
fl
\ i
i
:
» 1 1>
llllli
r
760
TllK NKISVors SYSTHM.
bcloDf^s to tlic rliiiu'iic('i)liiil(»n in the strict sctihc, or wlictlior,
as many tliiiik, it r('])r('st'nts a portion ol' llic [(allium. Tiio
Fi(!. 488.— One of ( 'allcja's islands in tlic olfactory tiilMMvlo of tlic niltliit. ' AfWr
('. Ciillija. La ickIo" oUiiloria dil ctrchro. >[a(lii(l. IHii:!. p. 1."). FIl;. :?. i .1,
niolcciilar layer : /;. layer ol' nyraniidal cells: r. layer of |piilyinor|)li(ius cells ;
((.ceil with MscendinK axis cylinder: h. lai'Kc seniilnnar cell; c. various
axones: il. cell with descending axis cylinder: c. axoile wliicli first ascends
and later descends: ./'. fusil'ortn cell of the deep layer; (/. larni' stellate c(dl
with ilcsccndin;; axone.
general reliitions are well shown in the aeeompanyincr diagram
tiiken from Eilinger's text-book (Fig. 4.S!)). The hippocampus
of one side is connected with that of the other by means of the
commissur;i hippociiinpi.*
The hij)pocainpns niiikes important connections by wtiy of
the fornix with (^?) the corporti mammilhiriii ; {f>) the nucleus
habenuliK ; and (r) the septum pellucidum and lobus olfiictoriiis.
{(((/ a) The iixones going to the corporti niammillaria pass
through the whole length of the fornix (cor])us fornicis) after
arriving in it from the pynunidiil cells of the iiippociimpus by
way of the fimbria hippocampi, f the subicnluni cornu iimmonis,
and the alveus. In the columna fornicis the fibres are arranged
* Often spoken of as the psaltcrium or lyra.
t The fimbria hippocampi is sometimes sjjoken of as the Urabus cornu
ammonis. Von Kolliker calls it the fornix inferior.
ii
in sevt'ral IjiukUcs wliicli ciiii be t'asily followcMl to tlic corpus
niiuimiilliirc. Here a part of the axoiu'rt end hy raiiiilyiiiif in
ainoiifx tlic dendrites and cell bodies sitnate<l in tlie nucleus
nu'dialis corporis iMarnmiliaris. A lar^'c part oi' tiie lil)ri'S, liow-
cvcr, forin a knee in the cor])Us maiurnillare, and then, apj)ar-
ently, cross over to the opposite side, on tho dorsal and post* 'tr
aspecits of the cor])ora niainniiilaria ((Janzer). The further late
of the crossed iihres is still not satisfactorily settled. Accordiiiff
to (ianser they appear to go further eaudaluard, in the teg-
Fi(i. 480.— Section throtisli tlio base of tlic l)niiii iuiil tho liipiiocaiiiiiiis lyiiiK )>e-
lU'atliit. (.M'ti'i-L. lOdiiincr. Ncrviisc ('<ntnilnr<;aiic. V. .\u(l., \^^i\t■/... ISlHi, S.
22rt, Vi'^. 154.1 Plexus cliorioidcus made siinpitT tluiii tlif actual.
(iI{()l'IM\(i AM) CII.MNINO T()(iI';Tlli;i{ (>F NKritoN'KS.
(O,
ry
mentum of the pedunculis cerebri. Other observers, among
them von (iudden and von Kolliker, follow them running
ra
%
■tr
'*"$
TTT??-. I
Is;^
Till-: NKHVOUS SYSTKM.
(lorsuhvani iH'tweeii tlic fiisciculi rctrolh'xi to becoiiii; lost in
tliis rc^^iou. 'IMic luHt-iiicntioiicd investigiitor * iiicliiu's to the
hi'Iiuf that they end in the iiiichMiK iicrvi ocidoniotorii, or in
the iiiK'h'Us ruber, or in both. It is not inipossibh' that tlicy
tt'rniinatc in tlio stratum fjfriscuni cciitrulc, sinec von Monuivow f
found this <i:r!iy matter atrophir on the left sith' caudal from
the corpus inammiliare in a case of atrophy of the fornix on
the ri<,dil side.
RunKin y ( ajai, however, does not find any tiecussation of
tlic coluinna' fornicis sue!) as (ianser and others dj'scribe.
Hy means of the neurones, tiie cell bodies of whicii are situ-
ated in tlie corpora mammillaria, othei- important centres may
l)e broufjjht under t\iv iniluenci' of the central conduction paths
of the olfactory apparatus. Kach corpus manunillare consists
of lit least two nuclei — (1) a larj^e medial nucleus, representin^jf
the main mass; and (■^) a smaller lateral nucleus, which occu-
pies an area correspondin«: to the anterior half of the medial
nucleus. It has for a lon<f time been kiu)wn that the corpus
manunillare is connected with the nucleus anterior thalami by
the fasciculus thalamomammillaris (or bundle of Vicq d'Azyr),
aiul with both the teijfmental and ])asilar portions of the cere-
l)ral peduiu'le by means of the fasciculi pedunculomammillares.
>>euroloi(ists workinjf with Weif^ert's method early noticed that
the bundle of Vicq d'Azyr always fused with the tegmental
bundle before entering the corpus mammillare. All believed,
however, that the two fasciculi had a separate origin in the
corpus mammillare. In this region again the method of (iolgi,
as ap])lied by Ramon y Cajal, has been of service, since it has
made it possible to demonstrate beyond controversy that the
pars tegmentalis of the fasciculi pedunculomammillares and
the fasciculus thalamomammillaris (N'ieq d'Azyri) represent
medullated axones which belong to the same set of neurones —
indeed, are ])ut the representatives of the two limbs of a fork-
like bifurcation which the stem axones of the cells of the nu-
cleus medialis corporis mammillaris undergo. The cells of the
* von K.illikur, A. Op. cit., S. 530.
f von Monakow, ('. Expcriincntcllc und patholo^'isch anatomische Uii-
torsuclunigeii uelier dii' H('zii')iuii<;eii tier sogeiianiiten Sclisphiire zu den infra
eorticalen Ojiticusccntren und zuin N. opticus. Arcli. f. Psycliiat. u. Nerven-
kr., Her!., Hd. xvi (1885), S. 181.
mv
(MtoriMNfJ ANI» CIIAINIXO TOOKTIIKU OK VKirilONKS.
ro'.>
medial iiuclous tire, iic(!(»riling to Kuiik'hi y Ciijal,* snmll, spiiidlc-
slmpcd, stellate, i»r Iriaiif^ular eells, which are provided with
miich-l)nmchiiij,' dcndritt's, mid };ive otT delicate axoiies dinicult
to follow on aeeomit of their tortuous eourse. The eell liodies
Fio. 490. — (troiip of cells from the pnrs nuMlialis of the mieleus corporis iiiiini-
niillaris of ii child. », axones. ( .\fter .\, voti Kiilliker, II:iii<lhuch dcrde-
wehclchrc, Hd. ii, Leip/., IHlKi, S. .")•„'!>, Imj;. tmii. i
and dendrites have ])een successfully inipreffiiated iji human
tissue (Fig. 4!)()). Their axones pass dorsahvard and somewhat
lateralward. In a reji^ion outside the corpus mammillare, each
hifurcates (Fig. 4!»1) into an anterior process running to the
nucleus anterior thalami, and a posterior, usually more delicate
* Ramon y Cajal, 8. Hoitriijf zuiii Studium tier Medulla ol)loiigata, etc.
Dentsch von Brosler, Leipz. (1896), S. HI.
•r
I
1. 1
mmmm
y
I
! (
;:
lU,
1 1
t
I
770
TIIK N'MItVol'S SYSTKM.
process, lookin^r iiliiinst like ii <iill!il('nil liriinrli which piisscH
ciitiihilwtii'tl, III Ciller Ihc tc^'iiiciitiil hiiiKUc of the fasciculi
[iciiiiiiciihiiiiiitniiiilhircs.'''
Fi(i. Iltl.— Siyillii) scclioii tliniiiKli tile iiu'diiil i>;ti't (if tlic ccii'iiiis niiniiniilliiro
(if a lu'wiiiini iiuiiisc. (Allcr S. Iviinioii y Ciijiil. liciliMn /inn Sduliiiiii iKt
.Mfiitilla OlilniiKalii, dr.. Hicslrr. I,(i|i/..' ISlMi, S. Ill, Kiy. :J(i. ) .1, incilial
|i(irliiiii (if niicli'iis <'<ir|iiiris iiiaiiiiiiillaris : />'. axuiiisiif llic cells liifiinatiiiK !(•
ionii twd (lilfi'i'int IiiiikIIis : ( '. fasiiciiliis pciliiiii-iild-niaiiiiiiillaris. pars Ic^-
mcnlalls i Uniihiiihiiiiiltl df vmi ( iiiddcii I ; IK axdiics (if white capsule; A,',
(•(iiiiiiiissiiia iiilcniiaiiiniillaiis ; /•'. aiiteridr ref^idii (if nucleus cdrpiuis uiaui-
inillaiis. pais inedialis; V. fasciculus llialaiiKi-niainniillaris \'ic(| dW/vii ; a,
cdllalenil friiiii axune df capsule; li. superficial splndle-sliapcd cell; c, cell,
tiie axdiie df which ;{des intd the hiindle /I'and liifiircates, seiidiuK luie liinh
iiitd r. the (illier inid ( '.
♦ von Kiillikcr has confiriiu'd the work of Ramon y ('aj"h "i"'! w have
at the luboriitory in HaUiriioiv been alilo to seo prpcisciy similar pietiircs in
.saj^ittal soctions of llie t'liiliryo jiif;. Tlu* deseriptioii fiivcii in the text holds
for the inoiiso. In the rabliit the branch of bifurcation goinj; tii the teg-
nientul bundle is stouter than that entering the faseieulus thalainoniaininil-
laris. \'on Kiilliker suggests that the bundle of stem axones be called the
(iU(»ri'IN(i AND (IIAINFNd TodKI'lIKU <>K N KI'lfONKS.
( i
I
Tlu' iMi'tliilliilrd iixoiics of tin- fasciculus tliiiliiiiHiiiiiiinriiil-
luris (N'ii'i irAzyr) puss dorsulwnnl ami sonicwlmt rntiiliilwiird
Fi<!. tre. — l''nnitiil scctinii tliniii}:li the mirlciis imiIh r, llic riisciriiliisliiiiKitiiiliniilis
iiic(li;ilis ami till' iMiclius \. iii'iild iiKitmii oC m ImImI imdiim'. I ACttr S. Kmiiichi
y<:i.i;il. Itcilni^' /.iiiii Sliidimii dii' Miiliillii • »l)liiiiyiil;i, etc., Ifrcslcr, Lcipz,,
ISiMi, S. II). I'i;;. :.'7. ) .1, fMsciciiliis liiii^'ilii(liii;ilis iiicilinlis ; /;. riisciriiiiis
|i('iluiirlllii-lilMllllilill;il'i>. |i;il's lri:ill('lil;ilis lliiiihnihiiiiilil i>i' vnii (illililiir: <',
foiiliii Di'd I tific lliniliriil.ii'iciiiiii 111' Mcyiii'i'l. (ir ili'cussiil in ti';.'iiii'iili ilmsilis ;
/>, licscciiiliiit; liiiiicllc ill Iniiiiiilici ntiiiiliiiis ; I', nucleus N. ociiln-niiptdrii
ri'cciviii;; ciillnli'r.-ils Irmn the iMscii'ulus liiu^iludiniiliN iiicdiiilis : /■', Idiik!-
tudiuMl lilircs in the Ic^juii'iiluin ; '.', dciiissMlin tcunicnli vrntiMlis < ("(irid's
lliiiihfiihrrii-.iiiiii) : II, nuddli' dccussiition or dccussitinn ol' vein (iuddcn's
liundli' : >'. i|iil helium nf iniucductuN ccrcliri ; /(, ciilliilcnils IVnm llir dc-
HCfHilini; liiindic in rcirniiitio rcticuliiris to thr nmlcus rnlicf ; h, hiruicatioii
of the 111 IPCS 111' the I'dinn T ; c, lilurs of liir^c ciililiri' wliicli cnlir llic l'ii>ci(ulus
lonKiludinalis nicdialis ; /), iixi mis of cells of nmiciis lu lie r wliich pass dorsiil-
Wiii'd. I,at(ial from llic iniclcus N. oculo-motorii one sees cells llie axones of
which, I'i'N'f yivinji oil' collalcials l<i the stratum Kiisciini ceiitrale. turn to
run lonKitiKliiially in the formatio leticnlaiis.
/(tsricnliis mammillariK j)rinr,epH, and that the bundlos correspoiidiiip to the
two limbs of bifureiitlou Ik; calli'd the fasciciihi.i tluilamomummillaris and
the fanciculuH tcgmi'iitoinmnmilhtris rcspoctivuly.
i> t
LI
•I <i 1
■(■■
> I
;
77i> TIIK NKIfVors SVSTKM.
toward the nucleus aiilcrior tluilaiiii, wlicrc tlu" (iltrcs divcr^'o
to coiiic into condicl with all port ions of (lir imicUmis. TIm!
individual axoncs inside the micleus l»fe;ik up into nunuTous
terminal Itrandies wliicli raniily freely in amoii}; the i-ell hodies
aiui dendrites situated there.
The luedullatetl axones of the pars te^nieutalis of lli" fas-
ciculi petlnnculoinauunillares {lldiilwnhiiiKlcl of von (iud<ien)
pass caudalwanl into the tt'jiuientnin of the cerehral peduncle.
Their ultimate destiny is still ohseure. Von (iudden * believed
the Itundle to he connected with the ^'anfflion profundum te^'-
ineiiti, which he descrihed in the rabhit, but this nucleus is
not well marked in human bcin^rs. 'I'he axones have been fol-
lowed by liaiuon y ("ajal in the mouse as extremely tine iibrea
throufj;h the red nucleus down into the pons in the region of
the corpus trape/,«»ideuin, where this te<,'mental bundle can still
be nuide out as a few line fibres lyinjr veidral to the fascicidus
lonjritudinalis medialis. ( ollaterals an- ffiven olT to the medial
8i«le t»f the red nucleus in passing,', lie linds, further, a decus-
sation of many of thcaxojiesof the bundle near the plane in
which is situated the decussatio brachii conjunctivi. This
dt'cussation may b(> desi<^nate(l the middle decussation of tho
t.t'<riuentuni, inasmuch as it lies between the dorsal decussation
(Meynert's /(i)i/ni)H'(ir/ii/c //iin/ir/d-rrininif/) ami the ventral
decussation (Forel's rrn/rtt/r IhtKlwnhrcuziinu) (KifJ. VJ'i).
Ileld's studies of the rejiion of the decnssationes tegmenti
lire ainonii the most interestinir that have been published.
Three of the liijures accoiupanyin*^ his article are here repro-
dnced (Fijis. 4!):5, 4!»4, and 4!t")).
The axones of the nucleus lateralis corporis imimmillaris
helj) to nnike up the ixirx htisi'hiris of the fasciculi pedunculo-
inammillares. This bundle of ineduUati'd axoju's, often spoken
of as the peduncnlus corporis mainniillaris, runs caudalwanl
into the cerebral ])e(lunc,le. The inferior termination of this is
as yet nneortain. A part ])robahly runs to end in the piiifilion
tejxmentuni dorsale of von (Judden. Flechsiji states that it
terminates ii\ the stratum firiseum centrale, and that thus olfac-
tory stimuli can be transferred to this gray matter and thence
to the nu'duUa oblongata with its nerve nnclei and autonuitic;
centres.
* von (iiulili'ii. (u'siiiniiiclti' AliluiiKiiiiiip'ii, No. xxvii.
I .IJ'.'f
I I 1 \^ l''<liiriiiihiii Iniiiiihiilniii/i.
^mSnrli-UH .V. itriihinintin li.
/•'ihlr si/hIi III I'niiii llir rnlli-
I'lilim miiiii ill! Ill Ihf I'liitro-
hitriiil /iiiiliiili.
' - l/i 1,1 • ; , , /B!9aSplL0 , .:.V / ' , ;Jz U. \ /V-kmh//.. /.■</lH^,l^■l^,r-
\%>':k'!i ■ ^■- tern ■
II I ill ill III inn jiinclivniii
I h'iliri' hi/hI f'Di friiin nnrleu»
mini- III /iiiiii'iliiK liilvnilii.
I''l(i. VX\. (>l)li(|ii(' scctimi lliroilKli Hie Imiiii stem of a cal f'ciiir days old. ■ \ft<»r
II. Ilrld. .\liliaiidl. d. iiialli. pli.vs. Kl. d. k. siiilis. ( icscllsrli. d. Wissciiscli.,
licip/,., M. .wiii, No. tl, lM!t»', Tui'. ii, Kin. 7.)
( 'iillirHliin HU}it'riiir.
, '^Z^?~\ I /' ''"*'' Hifsh'in fmui the
t^'.:;'^ T I ntllifitf US sii/iftiftr to
iV- — 4 ' "" '"'''■"' f' iiiniHCHH.
\\ 1 liiiili.r ilfHrfnitriis ninsrju-e-
► -H-V \-. f iHtliftn iitfi'f trtf/fttii nL
h'tfnr si/nti'iii fntui rnHintlnx
.. ^ ^ \ sufifiinr to i'viitfotittrntl
yf I .^ \ fuiiiruli.
----"^---» — \"-^ urh-ns ftrrri tn'uloinnftirii.
i A. l''ost'irtilus lumjit mtimttis
im-ilitilin.
.^x^^--
— ,-i*-
t - .' ' f t ■: r.i
Xlirli'iis I'lilivr.
Filiif sijHtiiii friim ni(-
rlfiis riihi'i' III fun to
hIiih lllllllllin.
■ 1,1 III nine un iiiftliulia.
liiiii.iniitiii Ifiiiiiiiili iliiimilis
{.y.l/nffti).
llirilKsilliii Iriiiiiiiili
ixnliiilin (Foitli).
X'liihiil lull I (•/</(■<•». 1 lirdchii iiiiijiiiiitiii
I ii'nliliHliir riiiiiminiiurr).
FlO. 404. — Oliliqiio, fwction throii);li tli<> tnaiii stem of a cat four days old. (.Micr
II. Held, .Miliiiiii' d. math. -pli.vs. Kl. d. k. slirlis. ( i<'s(llsili. d. Wisscnsidi.,
Lcip/.., IM. xviii. No. ti, IKSCJ, Taf. ii, V'ln- •>• 'I'ln' di'ciissatioiii.s tt'Kiuunti
an' well illiisl rated.
m
1 1
;
itf
i ,
,i :
77+
THK NERVOUS SYSTEM.
{ad h) TIk' liippociinipus is coniicctod with tlic iiucIouk
hiibenulii' l)y way <if tlic fornix and tlii' .stria niedtiUaris tiialaini.
Cfntinu'ssin'ii potitri'inr
■nhri.
.AucleiiH iierri <iciilii-
iiKilorii.
Niivleim litffiiilin niipr-
rior ( Flfchaiiji).
lAlHI'il'tflllS llHIflillttli-
ndtin iiiidiiiiis.
Xiifh'HK riilirr.
lifnr)iiniu I'oiijinirtiriint.
f.i'iinusrus lui'ilitilts.
Vlirr si/sli'iii fniiii iiiirliiin n
her to fiiiiii'iiliin Uilvriitin,
Ihciis.Kiitiii ti'ijtiiviiti rcn-
Inilis i/''<);(7/>.
riiliitl imii of (Irninsdfii)
liriiiiiii roiijinirtiri = coin
... : i...'t
Fid, UK"). — (»l)li(|iif sccliiiii tliriiiit,'li llu' luiiiii strm (if ii cat i
Iralinj; llic uriniii nl' iiiaiiy lihns of tlic lasciculus In
tViiiii the iiiiclrus latrralis superior • l''lcclisi<;i ). i AClcr
k. siiclis. (irsillscli. (1. Wissciiscli., I,('i|iy.., IM. xviii,
Fifl. 10. I
linirliii roiijiiurtin — com
niiKfiinr lirtirrcH .s-M/irr/'or
nuctii 1)/' //)(• rrslihiihir
iicriv.s of tin' tiid si(ti;s.
Icvcn (lays old, illii.s
lii.s liiii^'iliidiiiali.s iiicdialis
.\rici- II. II. 'Id. .Mdiaiidl.d.
.wiii. No. ti, |S!t;i, ■I'mC. iii,
Tlie term stria nicdullaris is ai)])lied to tlie band of white matter
adjacent to the taenia thalami. The hitter term is limited to
the line represeiitiiij; the jiinetion of the white matter with the
sini])le epithelial layer whicii forms, over a certain area, the
wall of the ventricle. The ta'iiia thalami hej^ins in front of the
corpus ])ineale and follows the free l)order of the stria medul-
hiris, l)eing continuous with the narrow epithelial lamina winch
covers the ]ile.\ns chorioideiis medius on its under surface (Kig.
40(i). At the foramen of .Monro the tuMiia tlialami hendsaround
backward into the ta-nia chorioida'a (His). A study of sagittal
sections of the brain of man ami aiumals shows that a number
of the fibres running forward frojn the hippocam])us in tlu;
fonu.x, near the region of the antei'ior commissure, turn back,
following an acute curve to enter the stria meduUaris thalami.
This bundle from the forui.\, which, by the way, ap])ear8 to give
■'■i-,r - ■■
OROUPINa AND CHAINING TOOKTIIKIl OF NKUUONKS.
3U8
ini.
•yriilii-
■iilits sii;h-
isiiji).
iiiililii.ili
(((I'.S.
ijiniitlviiiii.
tiiilis.
Ill IIKC/CI'S lit-
is Idtcraliii-
'i iTii-
■txittio
:= fDIII-
i/icr/or
tor
ics.
iUns-
•diiilis
IikII.i).
;il'. iii,
111 tier
1 to
the
tlu".
Ir tlie
lul-
lliicl)
|)\in(l
ittal
liber
the
iick,
iinii.
775
rise to the more ventral portion of the stria nuuhillaris, is joined
by u bundle of fibres from the f,Mnf,'lion basale. These relations
are f^rajihicjally illustrated in the accoiupiuiyinif scheme of a
sagittal section of tlu; rabbit's brain taken from von Kiilliker
(Kig. 4!)7). A similar scheme is to be found in K(lin<,'er's text-
l)ook. it se(!ms likely that in the stria medullaris axones run
in liotli directions, thoii<,di those we are now considerinjj; run
toward the nucleus habenuhe to end inside it amon<f the cells
and tiieir proc;esses situated there.
The nu(;leus habenuhe, a part of the epithalamus, is situated
in the trigonum habenuhe lateral from the corpus pineale. It
contains larger and smaller cells, the former predominating in
the lateral portion of the nucleus, the hitter in the medial por-
tion. It has long been known that the niuleiis habenuhe is
connected with the interpeduncular region by a strong band of
medullated fibres — the fasciculus retroflexus (Meynerti). Studies
by (iolgi's method undertaken liy van (iehuchten,* Ramnii, f
and von Kolliker J have shown that axones of Meynert's l)un-
dle arise from the cell bodies or dendrites of the nucleus ha-
Fui. 49ti. — TriuisviTsc section tliiouKli tlic tela clinrididt'ii voiitriculi trrtii and
its iifiKlil'Di'li'idd. I After \V. Mis, I lie Anatdiuiselie Nnineiielalui', ete.. I.eipz.,
ISll.'i, S. U)(>, I'M}?. 'Jl.) //. veiiliieiiliis lateralis; ///, vt'Utrieiiliis Ierliii>; Ci;
eiirpus calliisuni ; /•', t'oniix ; Tli. tlialaiinis; SI. in. stria iiie(liillari> ; SI, I,
strije teriLiinales ; 1'./, vena tiMiiiinalis ; /., lamina atlixa ; /. taenia tlialaini ;
•J, tienia ehiirididea ; .;, ta'nia I'cirnicis. The TiKure shows the transition of
tlie tii'iiiii' into liie epitlii'liai layer of the plexus eliorioiilei.
bonuhv, ami that the coarser fibres arise in the lateral, the finer
fibres in the medial portion of the nu'-leus.
* van Gelniehteti. A. Conlrihutions a ITMide (hi systeine iicrveiix des
Teleosteens. Collulf, Lii'rro et iiouviiin (IH'.ir)), {. \.
f Uiiniou, I). S. Aiialos lie lu Socicdad ospanola de historia natural., t.
iii, 2 Si>r. (1H04). p. 185.
t Op. rit., S. 4815.
51
m
Hi
11
; i
I
I
■i« V
If
776
TIIK NERVOUS SYSTEM.
a s <-S -r. -^ ^
j=' X .,'S 6t JS I- S
GROUPING AND Cn/'NTNQ TOGETHER OF NEURONES. 777
The modullatt'd axoiics of Meynert'sJ hutullc run (>l)li(|uely
ventral ward and somewhat caudalward to the interpeduncidar
/
Fi(i. 4i(K. — (iolfii prcpanUion from tlic pcdiiiK'iilar rcKiim ofu inoiisc live days old.
i.MKt a. von KiillikiT. Ilaiidhiuli <lcr (icwclii'Iclirc. Hd. ii, Lciit/,.. I'siMt, K.
4H7. Kif;. •>-". ' ''"'. <'iiri)iis inaiiniiilhirc : FM, fasciculi is rctrollcxus .Mcyiicrti ;
I>FM. decussation of its terminal axone.s.
region, where (in animals tit letist) they terminate in the gan-
glion interjx'diincularc of von (iudden. In the niousf, accord-
ing to von Kolliker, there is a terminal decussation (Fig. 4118).
-F.R.M.i.
Fk). 4!t!). — DiaKniin illustnitinK the relation of >reynert's tmndle to the red
iniclens. ( From a ^'construction hy Miss Florence Sal)in, Maltimore, lSi)8.)
/''./i'.3/.i. fasciculus retroflexus Meynerti enleriufi the anterior extremity of
the nucleus rulier: /•'. A'. .I/.7. fasciculus retrotlexus Meynerti leavinj.' the in-
ferior extremity of inu'Uus ruher ; A'. A'., nucleus ruher.
The course of these fihrescan be followed with the greatest ease
in the brain of the newborn babe.* Florence Sabin ha.s recon-
structed the bundle in this labortitory. She describes it as
* Curiously etiouKl', tlie more peripiicral fibres of Meyiierfs burulle be-
come iiipdtillated first, so that in horizontal soelioiis stained with the Wei-
gort-Pal method the section of the buntlle is colorless in the centre but
ileefily-stained blne-blaek at the periphery.
;i-r
I
f
i \
\
ih
w
778
THE NERVOUS SYSTEM.
follows: " The buiulle enters tho miclous nilxT, on its incdiul
aspect, near the anterior extremity of the nuc^leus. The i)lii('0
of entry is a smiill area which, nieasnred on the (h)rso-ventral
(liiiinctcr, is about one third the distance from the dorsal sur-
face. The fibres pass oi)li(|ucly throu;j;h tiie nucleus, so that
the place of exit is opposite the middle of the same diameter.
After emer^'ing froin the nuchnis ruber tlie fibres spread out
into a bundle, the dorso-vcntral diameter of which is nearly
three tinu'S as j^rcat as that of the cnterin<j bundle. This mass
of fibres lies just ventral to the nucleus ruber of either side,
'- '\'
Cdiii m i^.iit ra Imlieiiu-
Inris.
Tr. ()//. hiihi'ti. tivnim
I\'iirlrus lii'iiiiv /j,
Kiiistri(it}tm (•'
Oritjo tu'iiiic -
Conniiissin-it (Ulterior
Crii'hri.
'I'raif. hitlhi^i'iiistriiit.
Arfu (il/actorid-
CDf/iHs stritttum ■
,!(/. Ii)h. inf.
Tractu.t bulbo-corti-
ciilis.
Fdailii-
Fic. .")(!(). — Sflicinc (if ii liori/.ontal scctitm tliroURli tlic l)rniii of Cypriiiiis i'iiri)ii).
(After Ij. iMliiiKcraiid Alici' ILiiniltoii, from Kdiiiijcr's NcrvoscCcntrnlorKiiiic,
V. Aiitl., Lcip/.., 1S!H), S. 115. V\ii. its. I The fi^iurc show.s tlic iiiilividiiiil .siili-
(livisioiis of till' rliim'ni't'|ili;iloi) mid the ('oiir.sc of tlic olfactory tihrcs. .VII
parts pro.)cctcd into one ]ilaiic.
very near the surface of the fossii interpeduncuhiris. Some of
the root fibres of the nervus oculomotorius pass throu<^i; this
area. With a higli ])owcr ii few nerve cells can be seen between
these fibres, the group probiibly corresponding to the ganglion
VTv ff 'rifll BBB?
(iHoriMN'C! AN'I) <'1IAINI\(! T()(iKTIIKI{ OF NKl'liONES.
r79
intcrpcdiinculiirc " (Kij^. 4!»II). N'oii Kullikcr dcnios tlio exist-
ence of 11 gaiij^lion intt'rpcduncului'o in mun, and states that the
T
, cariiio.
nil siili-
■s. All
nine
of
i; this
■tween
liiLjlion
Fi(i. oOl. — Sclicmatic rcitrcsoiitatioii of sninc t^i tlic |)i'iiH'i|ta1 lU'iiroiie systems of
(111' olfiu'tiiry CDiKliiction path. I'nijcttcil intip sayitta) ]ilaiic. liiilh. tilf., 1ml-
Ims iiit'ai'tipriiis ; CdI. fnni.. coliiimia t'uniiiis ; Ti//. .soy*., ccilliciilus sii|m rim' ;
Coiiiiii. init., ('iiiniiiissura aiitci'lcir ccri'liri ; (hrii. ninm., ('(U'lHis niaiiiiiiillaic ;
('iiri>. /)(».. (•i)i|)us piiicalf ; (i. <;. h., unw^Wiiu opticuiii liasalc ; (11. ulf.. ^jldimriili
iiUactiirii ; (li/r. mnli. rhiii., Kyrns ainliiciis iliiiiciici'pliali ; 'ri/c. nlf. hit., tjynis
oUat'tdvius latiTalis ; di/r. ti. ni.. K.vi'iisdlfactdiiiis iiicdialis ; (>iir. .sniiidim. rhiii.,
cynis sciiiiluiiaris rliiiiciiccpliali ; 'r'.v'- •''"'"■"".. Kynis siilicalldsus ; l.inii. rrih.,
lamina crihrdsa ; A', n. tli.. iiuclciis anterior tiiaianii ; Xii. nlf.. iicrvi olt'ac-
torii ; Sucl. huh., iiiiclciis halximla' ; I'nl. rnrhri, pcilunciiliis rcrflni : >7/-,
limij. nird., stiia loiinitiicliiialis iiicilialis ; Sir. mcihdl., stria int<lullaiis ;
Tnict. tilf., tractus olfactoiiiis ; 7V(((7. o///., tnii'tiis opticus ; /, axonts of mitral
nils Ki'i'ifi t" i'^tria oll'actoria lateralis; / , axoiie of mitral eell ti'niiiiiatiii«
in tir.iy matter of tri^onum oll'aetoriuin ; //, axone of mitral eell terminating
in jjray matter, wlience axone ^oes to eommissnra anterior <'erel)ri ; //',
ax ones to anterior eommi.ssure ; // , (•entrifn;,'al llhre terininatintr in l>nll)iis
olfactorins; ///. ,.xone of mitral cell terininatinf; in j;yrns olfactoriiis
medialis; /I', axones of neurones 4'onneetiii'; the olfactory portion of the
linens (tiyrus amliiens and ti.vrus scmilmiarisi with the liippoeani]nis (<iiriiii
ammoiiis) ; !'. axones from hippocampus to fornix ; I' . axone to eommissnra
hippocampi: I", axones from fornix to septum iiclliicidum ; I'"', axones
from I'ornix to eorims niammillare ; I'"", axone from fornix to nucleus liii-
heiiuhe hy way of the stria mediillaris; 17. fasciculus mammillaris piinceps;
17 . fasciculus thalamo-Mammillaris Vicq d'.\/,yri : 17", fasciculus pedunculo-
mammillaris. i)ars tejimcnlalis ( llniibciihiiiiilcl of von Oudden ) : 17/. fasciculus
pediinculo-mammillaris. pars liasilaris ' ]iediincnliis <'orporis mammillaris i ;
17//, fasciculus retrotlexiis Meynerti exteiidiiif; from the nneleiis halxnuhi-
to the naiiKlion intcriieduiiclllare.
fihres of tlie ftiscicuhi.s retrottexus heeome lost in the himina
perforatii posterior.
;i
780
THE NKUVOUS SYSTKM.
1;';;,:
Is 4 U "1 ■ ;
Fni. oOa. — Schciiiiitic rcj)r('siiit;itii)ii (if soiiif (it'tlic iiuportiint iicunine systems of
tlic olfiictdry ciiiKliii'tiiiii paths; piojcciiini in luiri/mital plane, iliilli. olf.,
Imllms olfactnriii-. : Col. J'oni., culiiiniia I'lpriiicis: ('iiiiiin. (int., ccininiissiini
iiiitct'ior fcri'liri ; ('i>miii. hijiit., (•(iiiiniissma liippiicaiiipi ; Curp. cull., ciirpus
Ciilldsiiin: Ciirp. inion., cdrpiis nianiinillarc ; <iiiiiii. int.. nanKlicni iiitcr-
pi'diinciilarc ; (H. iilf.. >;lipiniTiili olfarturii : 't. ii. h., fiaiiKli"" o|iti('mn
basalc ; '>'///'. (imh. Win/., fj.vnis aniliiciis rliincncepliali ; (li/r. iliiuj. liiiii.,
Kynis (liaKonalis rliiiicnccpliali : tli/r. o. in., fjynis olfat'tidius nicdialis ;
(iiir. iilf. Int., Kyi'iis (ilfactnriiis latiTalis : (Ijir. .si'ininnn. rliin., fi.vi'Us semi-
lunaris iliinencepliali ; <iiii\ milirnll., jryi'ns sul)call(isus ; .Y. ii. III.. nucleus
anteriiir tlialami : .\n. nlf., nervi olfaetdrii : .\nrl. huh., iniele'is lialieiiuhe ;
Peil. irii'hii, peduneulus eeivln-i : .<//■. Iiinij. /<(/., stria IdnKilmlinalis lateralis;
Str. Iiinij. invil., stria InnKiludinalis niedialis; Str. nii'ilnll., stria' medul-
la res ; f, axones of mitial cell to l(il>us i)yrif()rmis ; / , axiuie iif cell
in firay matter iif tractus nlfactorius ; /". a.vine to basil optic fxanjilion ;
J[. II . axones to eonnnissura ant<'ri(U' cerebri : // , centrifuKiil axone
terniinatiufi in hullins olfaetorius ; ///. axone to fjyrus sulieallosns; 11', neu-
rones the axon<'s of \vhi<'h connect the temporal olfactory .sense area with
the hippocami)us ; I', axinu's from hippocampus to fornix; I'', corpus
fornicis; I' , axones from fornix to corpus iiiammillare ; I , axones from
fornix to stria me<lullaris; 17. neurones in c(U'pora mammillaria Kivinj; otf
axones which liifnrcate to form the fas<'iculus thalamo-mammillaris and
the fasciculus peduiuulo-mammillaris, pars te^nu'ntalis ; 17 . axones of
fa.sciculns thalanm-mammillaris Vic(| d'.\zyri t<'rmiuatinf; in the nucleus
anterior tlialami ; 17 , fasciculus peduiiculo-mammillaris. jiars tcKUientalis ;
VII. fasciculus pedune\ilo-mammillaris. pars basilaris ; 17//. fasciculus retro-
(k'Xiis Meynerti ; /A", axone from basil optic fian^lioii through stria niedul-
laris to nucleus habcniihe ; .V, axone from basal optic ;;anglion tlirouj;h the
fornix to the lii|ipocamiiiis.
GI10UPIN(J AND CHAINING TOGK/PIIKK OF NHlliONKS. -J^l
{(III r) Kxtc)i(liii<f from t lio fornix into tlie sctjjiini pclluciduin
are niuny iniMlulluti'd tilires, sonic of wliicii (loii')tles.s ri'jiri'sont
uxones of ci'lls in the hipiiocanipiis. Some of these may he
continneil fartlier into tiie hasal ganj^lion or even into the
olfactory h)he. In all prohahility these are aecomi»anie(l hy
fihres rnnning in the opposite direction, hut thus far detinite
statements concerning the exact origin and termination of the
white fihres of the septum pelluciilum are not justiliahle.
The study of the comparative anatomy of the olfactory ap-
paratus has heen prosecuted, among others, hy llerrick, A.
Meyer, Kdinger, and Alice Hamilton. The last-mentioned in-
vestigators have recently pictured the relations in the olfactory
api)aratus of the carp. Their scheme of the tracts in this lisli
is reproduced in Kig. 500. It will he seen that in the carp
the nu'dial part of the secondary olfactory path ends in what
Kdinger calls the epistriatum ; the lateral ]»art termiiuites in
more ventral portions of the brain stem in the posterior part
of the rhinencephalon. In Figs. 501 and 50:i I have represented
schematically the priiu.'ii)al groups of olfactory neurones thus
far made out. It is not to be forgotten, however, that these are
only schemes which must be recast as our knowledge of the
complex relations advances.
*fi 1
I
»ij,
i
1 1' ■
■„^^,
, j
11'
ii'l '|i
*
i * ■
jiil
iii
1
CHAPTER LI 1 1.
OF'TK NEURONES OK THE SKCOXl) OKDEIt AND OF IIKillEU
OUDKFtS,
The morpholof;;ic'al [lositloii of the N. opticus — (iiinf^liou rclls of the retina
— Their axoiies — Chiasma optieiiin — Fiiscicuhis eriieiatus — Kaseieiihis
noii-eriiciatus — Tnietus opticus — Its lateral ami medial roots — Termina-
tion ill ineseiieephaioii and dieiiceiilialon— l''il)r('s to (•ollifiiliis siijierior,
corpus jjenieiilatum laterale.and piilviiiar — I'oniniissura inferior (iiiddcni
— ("oiiiiiiissiira superior Mevnerti — Ileniis|plierie Imndle nf von (Jiiddeii —
('ominissiira ansata of Hannover — ('onimissiira liypotlialaniiea anterior
Traetiis peduneularis transversus.
Optic neurones of Order III — The structure of the colliciiliis superior and
the distribution of the axones arising there — The corpus geiiiculatuin
laterale and its connections — Uadiatio occipito-thalaniica ((iratioleti) —
" Optic radiatidu in the narrower sense" — Su()erficial and deep optic
paths of UaiiKui y Cajal — The cortical visual sense area — Ileinianopsia
and certain other pathological conditions — Pupillary paths — Schematic
representation of [)rincipal neurone systems in visual induction path.
3. Central Neurones of the Visual Conduction Paths.
It has beon pointed out on un earlier ptige that the so-called
N. opticus is in reality not a peripheral nerve at all, since it is
not comparable with true peripheral nerves which contain only
processes of peripheral neurones (sensory or motor). For the
visual sensory system actual analogies of the p'-riphertd sensory
neurones of other systems were seen to be the bipolar cells of
the retina, the cell bodies of which correspond to the " inner
nuclear layer," with dendrites distributed to the " outer molec-
idar layer," and with axones terminating in the " inner molecular
layer " among the dendrites of the ganglion cells. The true
nuclei terminales of the optic neurones of the first order, there-
fore, are situated within the retitia itself. The medullated ax-
ones of the ganglion cells of the retina, which go to form the
so-called X. opticus, are in reality nerve fibres inside the central
782 : - • -: " -^ -■
GROUPING AND CllAININHi TOGKTIIRlt OF NKURONKS.
rs3
hmm^
nervous system,* sind are iiniilof^ous to the inednllated iixoiies
of sensory neurones of the second onh'r of other sensory con-
duction piiths (e. ^., interiud urcuates and lil)res of the medial
lemniscus from the nuelous funiculi jjracilis und the nucleus
funiculi cuneati, nntdullated iixones of the mitral cells in the
bulbns and tractus olfactorius). The fihres of tlie optic nerve
and tract, l)esides in decussatin<;, resetnhle the medial lemnis-
cus, in that they terminate in the inidhrain and intt'rbrain.f
To call the band of fibres runninjif from the eye toward the
brain the " optic nerve " is therefore* to lie fiuilty of an incon-
sistency in nonu'nclature, thouf^h the term has been so lon<^
and so universally in use, before the actual relations were dis-
covered, that its elimination would be ditticnlt if not impossible,
even if the attemjit were thoujjht to be advisable. It seems
worth while, however, in order to avoid confusion of ideas,
especially for tiie bej^'inner, to enphtisize the fact that the
designation is ii misnomer.
The appearance of the ganglion cells in the retina is fa-
miliar to all. The irregularly oval cells are multipolar, the den-
drites running to the adjacent inner molecular layer, where they
branch nnmifoldly, and come into relation with the axones of
the bipolar cells. We have seen, in considering the peripheral
optic neurones, tbat certain of these are related only to rods,
others only to cones. The majority of the ganglion cells, on
the other hand, appear to stand in relation to both sorts of
bipolar cells, though it is not impossible that some of them,
especially the monostratified forms, are connected with only
one sort. The dendrites of some ganglion cells (Fig. 50;j)
spread out in one horizontal plane of the molecular layer
(monostratified cell), of others in several planes (polystratified
cells), of still others throughout the whole thickness of the
molecular layer (diffuse cells). The dendrites occasionally
* In the so-calli'il N. opticus are many pliu cells, siiniltir to thosf of the
substantia alba of other parts of the central nervous system.
f buys, and with him Aleynert (S. Strieker, A Manual of Ilistolopy. Am.
transl., ed. by A. 11. buck, Hvo, New York, 1872, [>. ()S8), compared the retina
to the bulbus olfactorius, and suggested that the optic nerve was not an ordi-
nary peripheral nerve, but in reality a central tract. Von Kolliker (En-
twickelungsgeschichte des Menschen und der huheren Saiigcthiere. ii
Auflage) stated also that the nervus opticus is really a part of the brain. lie
compared it with the tractus olfactorius and cunsictered the optic tracts
• analogous to the striic (^Ifactoria-.
784
TIIK NKIlVOirs SYSTKM.
■■'!■*' Hi'
>i 6lU
I il
pciictnitu ill unjonjj the vvW hodicH of the optic; ru'uroncs of the
first order (inner mielear layer). Ilt're and there at toleriihiy
rej,'ular intervals <;iant {,'an<,'lion cells can l)e made out. ThcHC!
UH a rule correspund to very hir^jc bipolar cells in the intusr
nucdeiir layer, and it has Ik'cii su<,'f,'eHted that those ant sij^ns
that the retina is di visible into more or less (hdinite j)roviii(!(i8,
which possibly may be of importance from a physiolo^Mctal stand-
point ( Krause).
The axones of the f,'an<,dion cells ))as8 into tluit layer of the
retina known as tlie " layer of optic; nerve fibres." Tliey all
run toward the "blind spot," or papilla nervi optici,and plunj^e
tliroii<,di the tunica' optici to enter the so-called nervus opticus.
In the retina itself the axones are, except in rare instances, iU>-
void of myelin sheaths. From the ])ai»illa on, however, they
are medullated, though, like other white fibres within the cien-
tral nervous system, they are distinf,Miishable from those of
peripheral nerves in that they possess no nucleated sheath of
Schwann (or neurilemnui). That the fibres of the optic; ncM've
really have their ori<,'in in the <faii^dion cells of the retina has
been proved over and over aj^ain by end)ryolc)<^ical study (.Mall,
His), l)y the study of .secondary de<;enerations (von Monakow,
(ianser, .Manx, and others), and directly by means of (iol;^i'.s
method (Tartuferi, Kaincni y Cajal).
Since von (iudden undertook the investiijation of the optic
paths * we have known that fibres of dilTerent ealibre oc;cur in
♦The contributions of Horiilmnl von (iiiddcn l)onrin}? upon tlic visiitil
oonibiction jiatlis arc the followinj;: (1) I'l^licr das N'crliiiltniss dcr CiMitral-
jrefassL' di's Aiij^cs ziini (Jcsiclitsfcldo. .Vrcli. f. Anal., I'liysiol u. wisstMiscli.
Med., Ikrl., 184it, S. .'>22-.'):52. — (3) Expc'rinientaluntersuc'lninp-n ueber das
pcriphcrisclio nnd ccntralt' Ncrvcnsystcin. Arch. f. I'sycliiat. n. Norv»;nlir.,
Ik'rl., \M. ii (IHTO). S. 09;{-7'2;i.— (iJ. 4, 5 and 0) loixT die KriMi/.nng der Nor-
v(>nfast'rn iin (!fiiasma nervorum opticoruin. Arch. f. Opiith.. Mori., Md.
XX (1HT4). 2. Al)th.. S. 24i»-268; I?d. xxi. Ii. Al)th. (IHT.")). S. l!»!)-204: Ud.
XXV. 1. At)tli. (isTi)). S. Urtii- 15il. xxv,4. Alith. (IHTi)). S. 2;i7-24«.— (7) Dem-
onstration von I'niparnteu ueber das .sog. (iunglion opticum basale, Kreu
7.\m^ (h>r SchiicrvfastTii im Chiasma. vorderc and liiiitcre Commissur des
Chiasma. Allj;. Ztselir. f. r.-yuliiat., IJorl.. I5(i. xxix (1H7:{); iJd. xxx (1874).
— (8) Exporimente, durohdiemandie versehitulenen HestandliciledesTractus
opticus zu isolircn im Staiide ist. 'i'asjc^bl.d. .">4 N'lTsamnd. dcutsch. Naturfilr-
.'iflKT in Salztjur;; (1881), S. 187. — (!)) Ueber die vcrschiedenen Xervenfaser-
systenie in der lietina und im Nervus opticus. Tascbl. d. .').') Versamml.
di'Utsch. Naturl'nrsciicr in Eisenach (1882), S. ;i()7.—( 10) Toberdie Schnerven,
die Sehtraetus, das \'erhiiltniss ihrcr gekreuzten und ungekreuzten Biindel,
*iA-
y
OKOUl'IN(J AND (MlAININd TOdKTIIKK <>K NKUIIONKS. 7H5
tlio ()])tit' nerve — (n) coiirHe fihrcH luid (fi) iiw lll)n'H. Salzcr's *
<!«»uiits iimdc ciicli optic nerve ('ontaiii 4;{S,()()() til»res; KniUHO
Hul)se(|tiently showed that, inelii(liii<r tJi(> liner tilires, eueli optic;
nerve contains l,0(K),0()() libres. There ure ul)oiit I, ()()(),()()(» eelU
in the fjiin^'iion <'ell layer of the n^tina. 'IMie rnajorif v' of re-
searches (von (inihh'n, von Monakow) point to the view that
thi' liner lihrc^s are connected witli tiie superior eolliculus of the
(!orponi (|nadri<,'einina, but von Leonowu states tiuit nniny ^n
also to the lateral jrenieulate body.
Having reaehecl the chiasnia optieiini, a lar<je proportion of
the libres (fasciculus cruciatu.s) of one iiervus optiinis cross over
"»'.,
Fni. rilKl. —Nerve cells friiiii llie |-etiii!i ol' (lie eliiri<, lATler S. |{miiii'iii v ('iijill,
Die IJetillil del- Wirliell liieie, (Jieed', Wiesli.. |H!H, Till'. V, I'i},'. 1. .1, (riili-
ffiioii eell wliicli spreails mil in llie lirst siililayer: />'. KMiiulion eel! I'm' tilt;
secciiiil sillihiyer ; T, sliiiill uaii^'licm I'ell t'cir Hie riiiiilli siililayer : /), iiiillli-
IMiliir reii fur tile seeciliil sillilayer ; /.', a eell wliiell I'lii'iiis twii liuli/dlilal
plexuses, llie lii'st beliiwllie rimi'lli sillilayer, llie seeiiiMl in the tliiril silli-
layer; /•', small eell willi Iwn line plexiiMs, llie lirst in the seemicl sillilayer,
the seediid in the rciiiilh. '/, ^iaiil eell which I'liniis three plexuses >iliiale(l
ill the seeiiiid, Ihii'il. anil r<iiiiili >iililayers; ./, cell with exlreiiiely lino
jilexiis in the lliiril sillilayer; A', eell which lininilies in the I'uuiih silhla.ver,
its liraiii'hes liicdiiiinu iiivulveil with an aiiiacriiie cell K<>in;; In the same
layer ; a. ecu I ri filial lilirc ; '), a mil her ceiilril'iiyal lilne the teiininal nf whii'li
goes ill a hori/iiiital (lireclinii heyunil the internal ple.xil'iirin la.ver.
to enter tlie traotus o])tlcus of the o])posito side; a certain
number of libres (fasciculus non-criiciatus), however, do not
cross but enter the traetus oj ticus of the siiine side. The fas-
ciculus (Tuciatus is ordinarily much liir<jer than the ftiscieulus
non-orueiatns ; the former apjjcars to correspond to the libres
iirisiiiff from the c^anj^dion cells of rather more than one half of
the retina on its medial or misal side, the latter to the libres
arisinff from the {.^iinj^lion cells of rtither less than one hiilf of
ihre Soli- mid Piipillarfasern iiiid die Centrcii der letzlercii. 'i"a;relil. d. oH
Versaininl. deiitscii. NatiM rt'irsciier in Striisstiiirg (1885), S. lUfi.
All those Imve boon reprinted. tofjctluT with his rescandies on other sub-
jects, in Hernhard von (indden's (iesainini'lle und hinterlassene .M)hand-
lunf^en. Ilrsp:. von Dr. II.(ii'ashey. Wiesbaden (188!)).
* Sal/er, F. ITeberdio An/ahl der Sehnerveiifasern und lier Kelina/.apfon
iin Aufje des Mensehen. Sitzun,i;sb. d. k. Akad. d. Wissonscli., Matii.-naturw.
CI.. Wicn. lid. Lvxxi (18K0), ;{. Ablii., S. 7-2:5. .
I.
I;
t'
ill i
:;l
If III!
!
!
mm^^'
YSC)
Till-: NEHYOUS SYSTEM.
the rc'tiiiii on its lateral or temporal side. The fibres of the
two fasciculi in the chiasm of luinuin beings ure not, however,
present in the form of definite bundles; those of one fasciculus
interweave witii those of the other of the same side and those
of both of the opposite side in so complex a manner that to
follow individual fibres, even in faultless serial sections, is prob-
ably an impossibility.
The secondary dcjjfejicralions obsi'rved in patholo<rical cases
in higher mammals aiul in human beings ((lowers,* Ki'llermanji,t
von Oudden,! I'urtscher,* Baumgarten,|| Singer and Munzer,'*'
Burdach,^ Marchand,| Schmidt-Himpler,^ .lacobsohn |) prove
beyond reasonaI)le (juestion that there is a semi-dccussation,
not a total crossing, in the optic chiasm.** In many of the
somewhat lower forms, for example in the guinea-{)ig, the de-
cussation is total. In the rabbit the decussation is tilmost
total, but von (iudden and others have stoutly maintaiiu'd
* Gowers, W. K. Patluilogischer Bewcis einer uiivollstiimligen Kreuzniip
dor Si'hiu'rvcn liciiii .Monsflien. (.'ontrnlbl. f. d. inoil. Wissensch., Hcrl. (18TH),
Bd. xvi, S. 5(52.
f Ki'lk'rmiuiii, M. Anatoniischc rntcrsnelnuifron atrophisclier Selmer-
von iiiit I'iiH'in Hcitrag zur Fragc der Sohiierveiikreu/ung iin Cliiasma. Stuttg.
(18T!»). pp. 44, Hvo.
t Op. cit.
** Part seller. O. Traiti' sur le croispinont ct ratroiiliic, des norfs ct des
tractus visuols. ('i)iig. pi'riod. iiiti'i'iiat. d'ophlli. (."oiiipt.-rciid. 1880, Milan
(1881). t. vi, pp. ;]20-;?'37.
I !?ainngai'toii. I'. Zur sog. ScinidcciissatiDii der Opticiisfascrii. C'oii-
tralbl. f. mod. WissiMisuh., Herl., Hd. xvi (1878). S. 501. — Zur SiMuidocussation
der Optipusfasern. Arch. f. Ophtli., IUtI., I5d. xxvii (\><H\), 1. Abth., S.
342-;M4.
^ Singer. .1., u. K. Munzcr. Deidvschr. d. nuitli. naturw. Ki. d. ^Yienor
Akad.. n<l. iv (1888).
() Hurdacli, I''. Zur Fasorkrcuzuiig iin ("liiasriui uiul in di-n Tractus ner-
vorum opticorum. Arch. f. Ophth., IJerl., Hd. xxix (188;5), 3. Abth., S.
135-14','.
X Marchand, F. Mcitrag zur Kentnniss der lionKinymcn bilatcralen
llemianopsie unil dor Faserkrcnzuiig im I'hiasma opticum. .Vrcii. f. Ophth.,
Berl.. I5d. xxviii (1882). S. 6IM)(5.
I Schmidt-Himider, H. Semidecussationsfrngeder Sehnerven. Deutsche
med. Wchnschr.. Hcrl., IJd. xxii (IHlHi), Yeroinsbeilagv . S. 15S.
J .lacobsohn. b. Zur Frage der Sehnerv.nkrcuzung. Neurol. Ccntralbl.,
Loipz.. i?d. XV (lSi)6), S. 8.*]8-84(t.
** t'f. also Drcschfeld, .1. Pnllioiogical Contributions on the ("oursu of
the Optic Nerve Fibres in Man. Brain. lioud., vol. iv (1881 -'82), p. 543;
vol. V (1882-83), p. 118.
GKoriMN'O AND CIIAIN'IXO TOCJKTIIKK OF NKUIJONKS. 7s7
tliiit eviMi ill this iiiiinuil tlierc is a small fasciculus non-oruci-
atus. Von (luddcn * expressed \\\v opinion that in all animals
in which the visual lields fall tofj^cther (l)inocnlar vision) there
is scmi-de(!Ussation in the ciiiasm, and that in all animals
in which the visual fields of the two eyes are entirely
separate the decussation is total. Tlius, in fish, amphihia, and
birds, the decussation is complete, while in mauimals and
nuin von (iudden aj?reed with the llannover-lleide view that
the decussation is partial.! The illustrations which accom-
pany von (iuddcn's articles are very convincing,'. In Fi-,'. 504
are sh( ivn (.1) the base of the brain in a normal rabbit; (/^)
tr.npt.d>~
r. opt d -i
tr.optdr
n.opt d. — J(^
n.oc d-
Via. .Wl. Hr.iius illiistratiin; :iti'()i)li,v lolliiwiiis; ('xiM'riinciital n-inoval ot'tlic cyo
ill ii ncwliiini raliliil. (AI'Iit H. von (iudden, ( it'siiiiin(dli' nnd llintirlassi'iio
Al)liaiidluiij;rii, WicsU., !SS!I, 'I'al'. xv. l''it;s. 1, ^. and :{. ) A. ISasc (if an
ililiiU laMiit's liraiii willi nornial ii|itic nerves. \\. liase of a ratil>it's Imiiu
ill wliieli the li.udit N. ciptiiiis is atiopliied. ('. liase nt' a raliliit's lir.iiu witli
l)ilateral at lopliy ef the Nu. oplici. iLiij)!.'!.. S. ii|iticiis de\lei'; ii.dc.il.. N.
ociilo-iiiotiiiius dexler: Ir.niit.il.. tr.ictus opticus dexter; Ir.p.lr.il., tnu'tus
peiliiiicularis trausversiis dexter.
the base of the bn, w of a rabbit the rijjht eye of which had
been extirpated at birth; and {(') the base of the brain of a
rid)bit both eyes of which had been removed at birth. In .1
the Nn. optici, chiasma opticum, and Tr. o])tici are Jiormal ; in
li the rifjht X. opticus and the left tractus opticus are atro])liic ;
in (' both Nn. optici are atrophic, and the correspond injj por-
tions of the optic chiasm and optic tracts have dcfj^enerated ;
the porticms of the optic chiasm and of the two tracts which
persist correspond to the c(M)' lissura inferior ((Juddeni), which
has no connection, it is believed, with either retina (rii/r iiifni).
The fasciculus non-cruciatus in the rabbit is illustrated in Fii,'.
* von Giuldon, H. Demonstration von Priipiiruten uelier ilus sojj. Gc
plion opticMnn Imsale, Kroiizinig dcr Si'liiierveiifiist'rn iin ("liiasma; vonl :
mid liintere (\)ininissur dos Chiasina. Alljf. Ztschr. f. I'sycliiiit., Rcrl.. .
xxix and x.xx (187:i-'74).
f .lohaiini's Mnllor tielioved that the idontity of tho reliiia in iiuin and in
animals is orfianieally condilioiicd. lle'i Imltz, on the otiier hand, thought
that it niiglit be u matter of edufal i. ((inerzoyene).
II
«M
.C2 —
ill I
IH
4!^'
7S8
TIIK NKRVOUS SYSTEM.
If opt d.
N opt s
fiOo. The aumi! bundle in niiin, niiicli more voluminous, is well
shown in the remarkiihle ease studied by (ianser,* in which this
hundle ran as a separate tract, practi-
cally completely isolated, from the
retinii into the optic tract of the same
side. The example is unique, and is
of such importance that I have had
fJanser's drawing reproduced in Fig.
5()(i. Although Keich,t of St. Teters-
burg, confirmed the results of von
(Judden, MandelstanimJ and ■Michel*
hiive supported the view of von
Hiesiadecki,! who, as early as 18(11,
asserted tli tt even in man the decus-
sation is total. Von Michel based
his conclusions u])on (1) serial sec-
tions of the whole normal chiasm
stained by the method of Weigert ;
{'I) sections of the optic nerves, optic
chiasm, and oi)tic tracts in cases of
degeneration in both man and ani-
mals ; and (;{) certain physiological
considerations.
Flo. 505.— HciiKiViil of tlic Iffl
hall' cif the rliiitsiiia (ipticiim
iiloii^ will) the ('i)iiiniissiini
inferior (iiiddciil in the rali-
liit. ( .M'lt T K. vciii (liuldcii.
(ii'Siliimit'lIc liiKJ IliiilcrlMs-
scilc Alilinii<lliiiiK<'ii. (iiii-
siicy, Wicsh., iss'l, Tat', xvi.
Fif:. !1. ) .V.oyi/.i/., atr(i|(liic
optic iicivc on rifjlit side, the
uncrossed liundle (/'. /(. i re-
tained; X.Djit.s.. N. opticus
sinister, atrophic; Tii.c. tii-
her ciucreuui : /. /., lol)Us
temporalis
L
ii
* (laiisor, S. Ui'licr (lie pcriplierc und ct'iitrale Aiiordiuing tier Schner-
venfiiscri) uiid uober das Corpus liij^eiiiimim anterius. Arcli. f. I'sychiat. u.
Nervenkr. Her!.. Hd. xiii (1S82), S. ;{41-;W1.
t Ili'ich, M. (Ml I lie Coiiiplote and Ineoiiiplete (/rossiiigof Nervous Fila-
ments (in cliiasriia iierv. <i[)ti('(iriim). Protok. /.asaid. Obsli. riissk. vraeh. v.
St. I'efersl)., vol. xli (1H74), pp. ;ir)l-;{«l. Alisir. in Ceiitralbl. f.d. iiied. VViss-
cnsoh., Herl.. !5d. xiii (1875). No. 2!>.
X Maiiilelstainm, )•-. I'eher Seliiiervcnkreuziing urid Hemiopie. Areli.
f. Oplitii.. Rerl., IJd. xix (IHTIi). 2. Ablli., S. :?9-r»8.
* Michel, . I. Uebcr den Haii des Ciiiasina nervorum opticorum. Arch.
f.Oplilli.. nerl.. I?d. xix (187:1). '-2. Al)th..S. nih .'«. Abth.. S. ;57r).— Ziir Frago der
Seiiiierven-Kreu/.iing im Chiasma. Ihiil.. iUl. xxiii (1877). 2. Abth., S. 227-
254. — reberSelinerven-Degeiieratioii iiiid Sehnerveii-Krcuzung. Fest-Sehrift
der ined. Fak. d. I'niv. Wiir/biirg z. Feier des jxx Oebiirtslages d. Dr. A. v.
Kfilliker. Wiesbaden (I887l.— Lehrbueli der Augenheilkunde, 2. Aiill. (18U0),
S. 4i)4.
I von IJiesiadecki. A. Ueber das Chiasma nervorum opt i('<trum des Men-
schen undderTliieri'. Sitziingsb. d. k. Akad. d. Wissensch., iiialh.-naturwiss.
CI.. Wien. Rd. xiii (18(11). S. 8B: und in ITntersueh. z. Natural, d. Meiisch.
u. d. Thiere. C.iesseii. Hd. viii (1802). S. l.W-l?.'}.
mm
'SMi:
iii
01U)UPIN(J AND CHAINING TOGKTHER OF NEURONES, 7^9
In serial sections of the normal chiasm ho found that tlie
fibres of one optic; nerve meet tliose of tlie optic tract of the
same side almost at a right angle, and he contended that the
view that an uncrossed bundle passing from the optic nerve to
the optic tract was due to the presence of loojjlike excursions
of certain of the fibres of the nerve for some distance into the
tract of the same side, before actually crossing through the
chiasm into the tract of tlie o})posite side. Von Michel can
not confirm the investigaticms of others concerning degenera-
tions either in man or in animals, and asserts that there is no
evidence from this source in his specimens in favor of a fas-
ciculus non-cruciatus. Finally, von Michel does not consider
semi-decussation a necessary physiological postulate. He argues
that if liomonymous bilateral hemianoj)sia * is to be explained
Fio. li'M). — Kcniim 111' tlif cliiiistiiM ii|itii'iiin and Iractus uplicus t'ounil in liuinan
bniiii iit iiiitopsy by S. (iimsrr. (Anli. f. I'sycliiiit., Hcrl., Mil. xiii, lss-,>, Tuf.
vi, Fif;. 11.) Tlu' fiisrifulus niiii-cniiiiilus iUxUt is seen us an isolated
bundle.
by the decussation in the optic chiasm the proi)ortion of crossed
to uncrossed fibres should be as 1:1, and contrasts with this
the admission of evcji those who adhere to the doctrine of
partial decussation, that the relation is as :{ ; 1, or as 4:1, at
most as 5 : :{. As further evidence against the generally ac-
cepted view lie cites the well-known fact that in by far the
majority of cases of hemianopsia central vision is sharp on
botn sides, ami urges that, in spite of the hypotheses which
m
♦ The condition in which there is loss of the liiterul visual field on one
side, and of the ined'al visual Held on the other.
I I
790
TIIH XKIiVOl'S SYSTEM.
havo bc'oii advanced to cxpliiiii this, there are no anatomical
grounds for the assumption that each macuhi lutea is doubly
represented.
\'on (iudden, up to the time when his brilliant career was
so tragically cut short, combated vigorously the do(!trine of
complete decussation, backing up his views with a large nund)er
of elaborate and most ingenious experi^aents, ^hich have been
sutticient to convince at least the majority. In his articles
from 1879 to 1885 ho dealt with all the objections which had
been raised, and in the miiuls of many definitely settled the
question in favor of a partial decussation in man and the higher
animals. He took carefidly into account the commissura
superior (Meynerti), the commissura inferior ((iuddeni), and
the hemis2)heric bundle which bears his name, and demonstrated
methods by which each of these, as well as the fasciculus cruci-
atus and the fasciculus non-cruciatus, can be individually iso-
lated. Von (iudden cited the experiments of Nicati,* who,
through the mouths of cats, cut the optic chiasm in the middle
line. The cats could still see, which would be difficult to
explain were the decussation total. Kven had they been totally
blind after the operation, the decussation need not be total,
for, as (iruetzner points out, we do not know how near the
uncrossed libres go to the median line before passing into the
optic tract of the same side. At von (Judden's instigation,
Bumm examined the retina in cases of degeneration as to the
origin there of the uncrossed and crossed fasciculi. liumm
came to the conclusion that the uncrossed bundle is related to
the lateral part of the retina, the crossed bundle mainly to the
medial part of the retina.
In von (Judden's time the embryological studies which had
been made threw but little, if any, light upon the topic ujider
discussion. Whereas von Mihalkovics and von KoUiker had
assumed total decussation from the mode of development, von
Baer, on the contrary, thought that the mode of origin of the
* Nicati, W. Do la distrihiitidn des fil)res ncrvouscs dans Ic; cliiasina des
ncrfs optifjiios. Airli. di' j)liysi(il. uoriu. ct patli., I'ar., 2. s., t. v (IHTH), iifi.
(158-678. — Preuve cxiKTiiuoiitaliMiu croiscnnciit iiuioinplet dcs fibres ncrvcusos
dans li! cliiasina dos ncrfs (i))ti(|ncs: section lonfjitiidinalc ct incdianc dii
<'iiiasnia non suivic dc cccitc. Conipt. rend. Acad. d. Sc. Par., f. Ixx.wi
(1878), pp. 1473-1474; also, Centralbl. t. d. mod. Wissensch., Bcrl., Hd. wi
(1878), S. 449.
■%-.
Ih liixl
under
>r liiul
lit, von
lot' the
l^ma (los
{78). I'l'-
[rvoust's
liiiui' Uii
Ixxxvi
lU.l. xvi
GROUPING AND rilATXING TO(}KTnEK OF NE['RONES, 701
chiusm wiis oonsonant with senii-decussiition. 1 liavo rocoiitly
(180S), througli the courtesy of Prof. MaW, exuniini'd tlie optic
paths of several human einhryos cut in various planes (sa<iittal,
coronal, horizontal), hut have found the relations so complex,
even in faultless serial sections, that I can not decide from the
appearances, at least in these carmine preparations, whether or
not the decussation is partial or total. A lateral hnndle can be
seen passing from the optic iierve throuffh the chiasm well
toward the tractus opticus of the same side, hut one is not jus-
tified in asserting from these sections that it actually enters it
to he distributed to the optic centres on the same side. What
strikes one most in the study of embryonic tissues is the inti-
mate rehition of the optic chiasm and of the oi)ti(! tracts to the
Ijasal plate of the diencephalon. I should not l)e sur])rised if it
should turn out that a considerable number of fibres, possibly
of no mean signiri(!ance, run into the base of the brain from
the chiasm and optic, tracts, to end there without passing
through the whole length of the latter to the regions usually
designated us the optic centres (lateral geniculate body, pul-
vinar, superior colliculus of corpora quadrigemiiui). Thus far,
studies with (Jolgi's method have not succeeded in demonstrat-
ing the partial decussation, tiiough much is to be hoped from
its application to the study of embryonic tissues, especially if
Horn's method of reconstruction be used in connection with it.
Since the death of von CJudden, von Michel has reiterated
his former statements, ami has received substantial support
from the Xestor of (Jerman histologists, von KiJlliker, of Wiirz-
burg.
At the meeting of the Anatomical Congress in Berlin in
18!)0 von KoUiker, on the ground of his own studies and of a
careful control of von Michel's preparations, stated that he had
come to the conclusion that the optic nerves undergo contplete
decussation in the chiasm in num and in the dog, cat, fox, and
rabbit. Curiously enough, this statement met with scarcely a
dissenting voice. Von Kolliker, later, in his text-book de-
scribed fully his findings, and rcviewcil at considerable length
the bibliograpiiy of the subject.* On the whole, he continns
the statements of von Michel and urges the necessity of una-
» von Kullikor, A. HiindlMich (Ut (Jewcbelehri', Md. ii. Iliilfto ii. S.
fifiO IT.
53
♦
i/M'
I
mm
m
■i\>
|rlt
tiki
792
TIIH N'KUVOl'S SYSTEM.
tomicsil demonstration of tlio uncrossed bundle. lie denies
the allef^n'd results of the study of secondary degenerations,
and emphasizes that decussation is not a necessary postulate
for the explanation of jjhysiological findings, and that even
were it apparently impossible to explain all l<nown physio-
logical facts without the assumption of a partial decussation
anatomists would not be justified in admitting decussation in
tlie chiasm until it iuid been actually demonstrated by ami-
tomical nu'tliods,
(Jruetzner,* in the summer semester of 18!t(;, undertook to
restudy the whole subject by the methods of the investigators
who had preceded him and by special methods deviseil by him-
self. From his own worli and from a consideration of tliat of
otliers he concludes that only a part of the fibres of the optic
nerves cross. lie made models of the chiasm iu which he made
half the fibres cross, while the other half passed through un-
crossed into the optic tract of the same side, lie then dehy-
drated these models and imbedded them in paraflin and cut
them into horizontal sections. In the sections: he could make
out only fibres which crossed, although he knew perfectly well
that oidy half of the fibres actually crossed. He concludes,
therefore, that tlie microsc-opical study of horizontal sections is
altsolutely of no value for the decision of the fjuestion whether
or not all of the fibres actually cross in the chiasm.
In the human case studied by Siemerling,t in which one
optic tract w'as completely destroyed, there was diminished
sharpness of vision in tlie op])osite eye, but the patient could
still see with the temporal side of his retina. This could not
have been possible had there been complete decussation of his
optic nerves. Xor are the experiments of Munk J or the clin-
ical pathological observations of Baumgartcn, Marchaiul, and
otliers {rifle .siipnt) compatible with tlie assumption of total
decussation.
11
* (inu'tziicr, I*. Kritisc'lic MemiTkunfjct) ucbcr die Anutomie dcs Chinsnia
opticiim. Di'utsche mud. Wolnisclir., IJcrl.. Hd. xxiii (lb!*T). S. 2.
f Siemciiiiijj, K. Eiii Fall {;;uiiun().sor Krkrankiing der Ilirnhaisis iiiit
Rctlu'iligiing lies Chiasma lUTVormn opticiiriim. VAn licit rag ziir Lclire
voiii Fasprverlauf iiii optischen Leitiiiigsa|)|iarat. Areli. f. I'sychiat. und
Xcrvciikr.. Rorl.. Hd. xix (1888), S. 4()l-4:{7.
\ Miink, H. Ziir I'hysiologie dcr (irosshirnriiuU'. Airh. f. Aiuit. u.
Physiol, riiysiul. Abtli., Leipz. (1H7H), S. I(i2-178.
^"SfmBL 1
(ilU)l'I'IN(i AND CHAINING TOOKTIIKK oK XHritONKS. 7(>3
Tlu' injjt'iiious cxpcritiu'iits of I'ick,* so far as tlu-v fro, tcTid
to conlinn the results of voii KiWliker. This iiivestij^ator, work-
ing with the rabbit, destroyed circumscribed areas of the retina
by means of a galvano-caustic needle, and subsequently studied
the optic nerve, the oi)tic chiasm, and the optic tract with the
aim of establishin<r tlii' topoj^raphical relations which exist be-
tween the retina and the optic nerve on the one hand and the
cliiasm and the optic tract on the other. His results led him
to conclude that the relations are very simple, the relative }»o-
sition of the fibres in the cross si'ction of one optic jutvc cor-
res})ondin<^ in toln to that of the transverse section of the o[)ti(;
tract of the opposite side. The dorsal and ventral fibres of the
optic nerve are the dorsal and ventral fibres of the opjjosite
tract, and in the same way the lateral and medial fibres of the
nerve occupy the same relative ])ositions in the optic tract of
the opposite side. His studies were carried out by the inethod
of Marchi. It is hij,ddy desirable that his results be controlled,
and that studies by the same method be carried out on animals
liiubcr than the rabbit in which there is evidence of a larjrer
fasciculus non-cruciatus. In the rabbit the uncrossed bundle,
if it exists, is very small, anil von (Judden missed it in his earlier
studies. The monkey would be a particularly suitable animal
for tbe prosecution of such a research.
^Fost intcrcstinir in this connection arc the painstakin<i and
extensive studies of the SAvedish investifjator Hcnschen.t He
has been able to accumulate a larj^c amount of bunnin luiitcrial,
whicb be has studied clinically and worked up patbolojjically
with care. On analyzing his results be bas compared his findings
thorougbly with the cases recorded in the bibliography, and
conies to important conclusions regarding the localization of the
bundles in tbe optic nerve, in the chiasm, and in tbe tract, and
the relations of these to the higher centres. His publications
* Pick, A. I'litiTsiiclmiiircii nolier die topoirniphisclii'ii Ri-zicluiii^en
zwisehen itotiim. Opticus mid i^ckrou/U'ii Trncliis Opticus hoim Kaiiinclien.
Nova actader Kaiscrl. fjcop-Carol., Deutschen Acadcmie dcr Xaturforschcr,
Bil. Ixvi. Al.sinict ill Xounpl<ij;isrlu's ('ciitraUil., IM. xx (l^tlC)). S. 091. Cf.
also I'ick u. Uerrenliciscr. I'ntcrsucliuiifccn uchcr die lnpof^rapliisclun Bc/ic-
hiuigc-n zwischen fietiua, ujjticus uud gekrcuztcn Tractus o[)ti( us liciiii Ka-
ninchcu. Ilallc. ISOo.
\ Hcusclicn. S. K. Klinisclie uud ariatoinisciii' Meitriige zur Pathologic des
Gchirns. Zwcitcr 'I'IumI. Ui)sala (1892), S. -JIT tT.
»SH-I
"if
mi\^'
llli
Iff' 11 J,-^' ■!'*"?
I
Nerviis oplicia_
dvxtcr
B
c (=h'iii.bi foKiciihu crufialusdonaliii
dMu
fattUiilus rrutiatm
venlrali-i ~
fuiciciiiuj njn-crueiatm vntra/u
e (=Fig.F)
Traclus oplicu* dixler
Fn-r:riiluA non-cruriatiis diir.iuL.\
Fa^nculus niiirii/iy-i ^
/ not-rriuiatu.' ,/o/ \„/i<
_ Fiitciculiu miifulun i
\ fiiir;ii/u.\ riijrii/iins
(ruc'aluj vcntruli.-,
Fanrieii, a tnitriiltuia
non- crtuiiiliis tfnlra/i.)
F(d
Fm cd
Fcv
,Fn-c.d
^Fm.n-c.d
D
Mtdiul
Fm.c.d.
Fm.fy. \
t n-c.v
Lateral
Fm n-
Fm.cy
Fn-c
Fin.ii-i: V
Fc.
F.m.
Cjni'ru.<s:."-it inf.-rn'rCfUdd^n: fn<.d Fmn-cU.
Fiisaculti.t
\ nJii
/• ' " fm.c.it.
Fig. 507. — Local izatton of optic fibres iHcaschcn).
^
fialiis dorMiU.\
(iUOUPINU AND ClIAININd TOGRTllEK OF NKlllONKS.
'1)5
represent h mine of ricli inateriiil, and must be consulted by
every student who wishes to <;() beneatli the surface in this
field. In V\^. 507 is reproduced the ))late in which his conclu-
sions refjarding localization are epitomized. The fasciculus
non-crueiatus of the optic nerve (see ueeompanyiuf; tifi^ures)
arises in the main from the temporal side of the retina. It fol-
lows a tolerably isolated coui'se as far as the chiasm, occiipv-
ing the latero-ventral portion of the transverse section of the
optic nerve. The fasciicidus cruciatus, on the other baiul, is
situated nu)re medially and dorsally. The bundle from the
macula lutea (fasciculus macularis) on each side runs in the
central part of the ojjtic lu-rve, and nuiintains its central jiosi-
tion in the optic chiasm and in tlu' o})tic tract. The relations
of the crossed and uncrossed bundles to
the inferior aiul superior commissure in
the optic tract will be sutticiently clear
from the diagrams if the legends be
consulted.
The researches by Marchi's method,
carried out by Singer and Miinzer * ami
Ramon y Cajal,t support the doctrine
of partial decussation. Kvcn in the rat
and mouse, in which it has been gener-
ally supposed that decussation in the
optic chiasm is total, Hamuli y Cajal
finds an uncrossed bundle, and states
that it goes only to the lateral geniculate body of one side,
while the crossed bundle goes to the lateral geniculate body
and also to the superior colliculus and the thalamus.
We must ('(mclude, tlu'refore, from the evidence before us,
that as a rule the decussation in the optic chiasm in man and
of higher animals is ])artial, not total. That in individual cases
there may be considerable variation seems certain. Even in
the anatomy of Vesalius we find a luunan case reported in
which the optic chiasm was entirely absent (Fig. .oOS), the right
optic nerve going bodily over into the right optic tract, and
Fi(i. 5ns.— Aliseiici' <)t'(ii)tic
cliiiisni. ( Al'tir Aiidnas
Vcsiliiis ; tiikiii iViuii A.
l{;iuli( r"stcxl-l)iii)k, I'ni'-
sciUi tiKura ii-rv(irmii
(|iiiis liir tlcsciiliiiiins duc-
tus cxpriinitur. uv, cci't'-
liri piii'tiiiiiciihiiu iiiilicat.
m
R
'V
* Siiifrcr and Miinzer. Heitriige ziir Kcnntniss dcr Sehnervcriki-fuziiiig.
Wion. 18HS.
+ Hiimoii y Cajal. S. Aim. ile la Socied. Kspaiiolu di hist., iiat., 2. Ser.,
t. iii (lMy4). J). -I'i,^.
'W
TliM NHlJVors SVSTKM.
licnlo * has collected a iniriil)i'r of siicli ciises from the l)il»li-
o^^nipliy. It is not iiiipn.ssil)li' tlmt occiisionally tinTc is actually
coiiiplote decussation in the chiasm, in which event we siiould
expect total amhlyoi>ia in the opposite eye (instead of hemian-
opsia invoivinj^ the two eyes) to t'oHow upon lesion of one optic
tract. The rarity of such ohservations is, however, very strik-
in<,', especially since the exact studies concerning,' hemiano})sia
have been inaujjfurateil. between tiu-se two possible extremes
of no decussation and total decussation there nuiy he all sorts
of degrees of decussation, the most fre({uent projiortion of un-
crossed to crossed fibres in man i»robably being ai)out as 1 : 5i or
as ;{ : o.
The optic tract on each side behind the chiasm runs around
the cerebral peduncle of the same side and arrives at the
junction of the mesencephalon Avith the diencephalon, where it
divi<les into two distiiu't roots, (1) a lateral root and {'i) a me-
dial root (Fig. .50!)).
The optic tract on the right side, for example, includes the
fasciculus cruciatus from tiie left optic nerve, the fasciculus
non-eruciatus from the right optic nerve, fibres of the commis-
sura su))erior .Mcynerti, fibres of the commissura inferior (iud-
deni, libres of tlu' direct hemispheric bundle of von (Judden, a
certain number of centrifugal libres running from the higher
centres of the retina, and possibly libres of still other cate-
gories.
The fibres of the lateral root of the optic tract include the
centrii)etal and centrifugid fibres connected with the retina, and
terminate (or in case of the centrifugal fibres have their origin)
in the lateral geniculate body, in the pulvinar of the thalamus,
and in the superior colliculus of the cori)ora (luadrigcmina.
In these centres the terminals of the optic neurones of the sec-
ond order come into conduction relation with the cell bodies and
dendrites of the optic neurones of the third order. Of the
optic neurones of the third order, those in the lateral genicu-
late body and the pulvinar send their axones, in large part at
least, to the visual area in the occipital cortex, while those in the
superior colliculus of the corpora quadrigemina send their ax-
ones in large part to enter into conduction relation with nt'U-
mm^
* IIoiiIp. .T. FlandtMifh dcr systeinatisclieii Anatomic des jMenschen.
NorvcMil.'liro (IMTO). S. '.mi.
T cate-
(.'
the
I, and
ri.uin)
IlllUS,
iniiui.
(' soc-
'S iuul
)f the
('ni<'n-
lart at
in the
cir ax-
h mni-
OUOUIMXG AN'I) CilAINlXd 'nuiKTllKIl OF NKrUONKS. 797
rones which throw the eyi'-miiscU' luich'i uikUt their inntienoo
{I'iile infra).
St
Ccb
Fiu. 5fl!t. — A pdi'tioii of tlic ri^lil ci rclmil liciiiispln re resting on tlic puliis
froiitalis. to ilhislnitc the l);i>is cciclui. i.Mlir.l. IIciilc. HiiiiiUnicli dcr
Ncivciililirc (lis Mcnstliiii. II. Anil.. I'.ramiscli., ISTit. S. 155. Fi^. so.) /;,((,
hnicliiimi (|iiiuliiKoiiiiiimii Mipcriii.s ; />'(■/(. luacliiiiiii (|iiii(liij;iiiiiiiiiiii iiil'criiis ;
('ill. pcdmiciiliis ri'i-i'liri : djl. corpus ;;ciiic-iiliitmii latci-iilc ; Ciiiii. corpus
^'ciii( iilaluiu uii'dialc : rc(/, lirailiiiini conjuuclivniu ; Tn, cliiasuia opiicuui;
Ti/', colll< iilus iiifciior ; fV^^. colliciilus supi rioi- : /,. Icuiiiiscus : /'r, puh inar
of llialauius ; Sjut, sulislautia pciloiata aiiI<iioi' ; SI. siria tcniiinalis ; //'.
ti'aclus opticus. The radix uicdialis and tiu' radix lati ralis arc well illus-
trated ; t. cut surface of tip of temporal lolx- which has lieeii removed.
The hiter'l jjeiiicuhite hody and the superior colliculns of
the corpora quiidrifiemiiia htive aecordin^ly Iteen (U'siifiiated,
especially by the (ierniiin writers, iis "primary optic centres" in
the brain. This desiixnation is, however, not wholly suitable,
for we hiive seen that the j)eriphi'rid ()])tic neurones correspond
to the bipolar cells of the retina, and the ganglion cells of the
retina retilly represent a part of the l)riiin. It would be much
more logical, therefore, to desiguiite the ganglion cell hiyer of
the retinti as the priintiry optic centres of the l)riiin, and to
iiiime the latend geniculate body, the pulvintir, and the superior
colliculus of the corpora (piadrigemina the "secondary optic
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798
THE NERVOUS SYSTEM.
centres " of the brain ; for it is obvious thiit the ganglion cell
layer of the retina corresponds to the nucleus funiculi gracilis,
and the nucleus funiculi cuneati of the general sensory path and
the termination of the optic tract in the superior coUiculus and
the lateral geniculate body corresponds to the terminations of
the medial lemniscus in the mesencephalon and in the dien-
cephalon respectively. The neurones eAtending between the
lateral geniculate body and the cortex would, for the visual path,
therefore, i)e the analogues of the sensory neurones of the thii'd
order of the general sensory path extending between the ven-
tro-lateral group of nuclei of the thalamus and the cerebral
cortex.
The exact areas occupied in the optic centres of the mesen-
cephalon and diencephalon by the terniiiuds of the fibres of the
lateral root of the optic tract have been demonstrated by the
degeneration experiments of von Monakow. After enucleation
of both eyes in the new-born puppy, this observer found, on
killing the animal at the end of six months, that the gelat-
inous substance of a large part of the lateral geniculate body
— that portion of it which he designates a — undergoes degener-
ation. This substantia gelatinosa consists, in the main, of tlie
terminal branches of the fibres of the optic tract.
In the dog von Monakow divides the lateral geniculate body
into several nuclei — a, a^, />, /vi, and v, the ventral nucleus.*
While a few of the optic fibres apparently terminate in a, b, h^
and in the ventral nucleus, by far the majority of them end in a^,
the dorso-caudal part of the lateral geniculate body (Fig. 510).
The fibres going to the pulvinar from the lateral root of the
optic tract in the dog are distributed to the superficial part of
the dorsal zone.
The fibres of the lateral root of the optic tract which go to the
superior coUieulus correspond, so many have thought, to the su-
perficial white matter of that body (von CJudden, Forel, ({anzer,t
* Monakow divides the corpus peiiiculatiun laterale in the dog into two
main parts — (1) den Sehsplidrenautheil (a, h, h,, and r). and (3) den h'elina-
nnlheil («i).
f Ganser, S. Ueber die Anatoniie des vordoren IlUgels voni Corpus tpiad-
rifjominum. Ardi. f. Psychiat. und Ncrvonkr.. Herl.. Hd. xi (1H80). S. 278-281.
— UfbiT ilio |)i'ripiu'rf und {'cntralc Anoi'chiung diT Seiniervcnfascrn und
ueber das Corpus bigoniinuin antcrius. Arcii. f. I'sydiiat. und Norvonkr.,
Bcrl., Hd. xiii (1882), S. 341-381.
GROUPING AND CHAINING TOGETHER OF NEURONES. 7»j«)
Pulvinar.
Lamina mrdiiUaris
lateralis.
A/'f^.;
/
Corpus geniviiliitum
litterale ui,).
,'Trartus ojiticua.
■^ Ijn/er of
irliite
iiKitter,
V
J
^■i ■'■■■'■: '■ "~:- .v
v>l- . ■ .' i ' U''"' ilintiuUi-
> \.-. . ■ -J.-f . ■! ...
.■■if'
Sfec-*'*-
,4-
','.'v"
id;**'"
a^-
•jii^^
rd/e (bi).
!■>•.' /."T C(irj)iis
: . .■ A y f/ciucii/fi-
WV' •/ (urn ?(i/e-
mm
,;<?^.^
Basis pedunculi
^■-/.K
'' Tractus opticus.
'Zona retimlari^.
Hemisplieric hnniile
(V. (iudden).
PiihiiKir.
Corjjus yeuiculatum luterale
' <Ul).
B
i
\iM
• ..■.>'■.. . ;■ ■.' "i;..;- .■; Corptis ;ieniciiliit\tm
V' "..'•'••■ ■■•■•''.'''j''''i »"'' luterale ihi).
'^''. ■■■:''■''.:. -^'\ ,. l'''f>''<'S to hemisphere,
'■v.:'- '.-■Jam C. yen. lat. dv.
. . • '?'.>i ^ "'/f^:^'. Zima reticularis.
:^ .#^" -A-^ji'
' ■.Ki!.'^' --Jfgfli*-?-''.*'
m
m
\ .'ff-'ii 'I '-'Jl^' '' - Uemisphfrir bundle of
V'-r' J^ '■• ttudden.
,*'*
\ Basis pedunculi.
Lamina medidlaris lateralis.
Flo. 510. — Frontal sci'tions tlir<iiit.'li llic cnrpiis Kciiinilatiini latcnilc ipfiKioc. A.
Scctidii tlircpiiKli caudiil plitiic of a lualtliy ilnj;: 'i. imclciis rnmtalis dorsalis
ol' tlK' ('(irpus Kciiiciilatmii lalcialc: at. imclrus caiiilalis ('oi-silis ; h,. caiidal
vcntial nucleus lit' tlir rni'iius (ii'iiiriilalinn latiralc : c, must ventral iiiieleus
tit' eiirpiis },'<"i«'"'alMiii latenile. li. Frmital Mcliuii tlirmiyli tlie eorplis
fjeiiieiilatiMii lalerale iit' a (Infj t'riilii which huth eyes liaii liecn ciincleated.
(.\t'ter ('. vim Miiliakow, Arch. I'. I'sychiat., lid. .\.\, l8Wt, Tat'. .\iii, Fins.
i.i
li
„■ '■'■t'S
'il.r
ir
'I
i
'PI ".
W
II
800
TIIK NKllVdUS SYSTEM.
von Monakow,*) althouffli, as Tartufcri lias poititod out, tlio
most iiUMlial part of the supi'rticial white matter belongs to
another system of iibres, and reeently it has seemed more likely
that the optic fibres are those which assume an antero-posterior
direction, just beneath the nippe riiicrec.
The /(i/rn// i/r/iicKldte bo(/t/ in imin, (isitoahiWy in horizontal
sections, is heart-shai)ed, the apex bein*^ directed forward. The
appearance is very characteristic. The mass consists of alter-
natin<jf, somewhat irregular layers of giay ami white substance,
(Fig. oil) the white nuitter consisting of optic tract fibres in
the main and |)artly of the meduUated axones which jiass from
tlu^ lateral geniculate body into the ojitic radiations to pass to
the cerebral cortex. The gray matter of the nucleus contains
cell bodies and dendrites of the optic neurones of the third order.
In man, probably SO per cent, of the fibres of the optic tract end
in the lateral geniculate body (von Monakow). The eiulings of
the fibres of the optic tract in the lateral geniculate body have
been studied by (iolgi's method, by 1*. Ramon, f von 'v«"illiker,J
and Ramon y ("ajal.** The terminations of the oi)tic fibres in
the lateral geniculate body of the newborn cat are well shown
in the accompanying figure taken from Ramon y ("ajal's article
* The prineipal i'niitril)iilioiis (if vmi MDiiakow as roganls tlic uplic iicrvo
find o])ti(' cent ITS are tlie I'ullowiny; : I''x|iei'iiiientclle iiiid patlioldfjiseli-ana-
toiiiiseho I'ntersiicliungeii uoberdio I?e/ieliuii>,'oii der sogenaniiteii SelispliJiro
zu <lcn itifnu'orticaleii ( )[)tieiiseentren und zuin N. opticus. Arcli. f. Psycliial.
u. Xervenkr.. Merl., IM. xiv, S. fi!)!». and lid. xvi, S. l.")!. :517.— Kini,4-es ueher
die I'rspninirscentreii dcs \. opticus und ueher <ii(^ \'ei'l)indunicpn dersellten
init derSehspliaro. Arch. f. Anat. u. Physiol., Physiol. Ahth.. lieipz. (ISH.")).
S. "J'-J!*. — I']\i)erinientelle nnd pal li.-anatoniisciie rtit('rsu<'hMni;en ueoer die
oplischeni'entn'ii und iSahnen (Xeue i'"olge). Arcli.f. Psycliiat.n. Xervenkr..
IJerl., IM. XX, S. 714.— I'lxperimentelle nnd path.-anatoini.>;clie I'ntersncii-
unp'ii ueher die opt isclieii Cent ren nnd Halinen in'hst klinisclieii Meiiriiuvn
zur corlicalen ilenuano|)sie nnd Alexie (Xeue {''olirc). Arch. f. Psycliijil. u.
Nervenkr.. I?erl.. 15(1. xxiii. S. GIMI; \\,\. xxiv, S. 2'^!).
t Karnon, P. (l)(}aceta sanitaria de I'.arcelona, iii (IHOO). Xn. 1. p. 10; (2)
Iiivesli>^. sol)rc los cciitros opticos de los vertehrados, Tesis del doclorado
(1890); (3) Hlencefalo de los re|)tilc.s, Ikrcelona (181)1 ). pp. 11-22; (4) Invest,
on el encefalo de los hat racios y reptiles, cnerpos genienlados y tnliercnlos
ouadrijreiiiinos de los nianiferos. Zaraj^oza (18!)4).
:f von l<i)lliker. A. Verhandl. il. anat. ("Jesellsch., .Fena (18!).")). S. Hi; also
liandhucli der (iewelielehre des Menscheti. Leipz. (IS'.MI), Ud. ii. S. ."iSo (T.
* Kanioii yCajal. S. neitragzuin Stndinin der .M"dulhi Ohlonf;ata. des
Kleinhirns nnd dos Ursnrungs der Gehininerven. I»entscli von Hrosler.
I..M|)Z. (18!)r)), S. 101 IT.
ill!
(JHOUIMNTr AND ("IIAINTNG T()(}KTIir.i; (>F XErUONHS. SOI
(liK'lorailo
(Fi^. T)!"^). Tlio tcniiiniitions of tlic optic fibros in tlic ))iil-
viniir of the tlialanius iirc well illustnitt'd in von Ki'dliivcr's cut
(Fig. 5i;J). From the manifold divisions of the terminals of
CA
Fl(i. 511. — Iloii/diitnl i)lili((ll('si'(liiiii tliripiit;li tlic citcIiimI indmirlcaiid liyjiiitliill-
aiiiiis ; I'.il stiiiiiinj;. ' At'trr.l. l»rji riiif, Aiiatninic ili ^ ci litres ik rviux. I'iiris,
isil"). |). (mI. Fi^r. ;!~"). ' .1 .1/, ilaiistiiiiii : .((/.aiimiliictiiMi nlni : lli(Jii. hrarliiiiiii
((tiailriuciiiiiiuiii smitriiis: l!i<Ji). I>railiiiiiii <|iiailriuciiiiiiuiii iiiriiiiis ; CA,
lii|)li(i(aiiiiiiis : <y. capsula cxti'iiia : fV;. I'asi'ia dciilala liipiiiicaiiipi ; ('<u'.
(•iii'pii> uciiiciilatuiii latcralc; ('(ji. rorpiis uciiiiiilatiiiii iiicdialc ; Ciji. capsula
iiilcriia pai's ipccipitalis ; Cirl. rctrolcinil'ipriii pcirtioii nl' pars mcipilalis capsiilii'
interna': CM. (•(Hiiiiiissiiia supfiidi- Mcyiiciti : /-./ly), substantia piilmata
posttiidf ; Fiiiji. fasiiciilus nl' tlic (■oiuinissura postciior circhri ; /V, liiiiluia
liipp<i(anipi : I'li. lasfinilus loiiizitiidiualis int'frinr ; /V/i. rasciciilus UuiKi-
ludinalis nicd' 'is; l-'l. liuudlc iif 'riirck ; /•'». t'asciciiius liiiciiialils : Ir.
lauiina rcu'iK'a : l.ms. laiiiiua nu'ilullaris siipci'liciaiis : /./«. sulislantia iii^M'a ;
.V.I, nucleus aiii.vjjdala' : AT', cauda iiiiclii caiidati : .\7.. piilanicn ; .\7,',
nucleus riiliei': /'. hasis |)cd:uiculi ; I'hii. plexus elKirioideus : I'Tiiil. rasciculus
]H'dunculi>nianiinillaris. pars liasilaris. <u' peduinle cil' the inaniniilhii'v limly ;
/'«/. pnlviuai- ; '(<(/, cnlliciilus siiiieri(U- ; /. siiperliiial layer: .'. luiddli' layi'i- ;
.;. deep layer: li'iii, leiuiiis<'iis uic(liali>: /.'/'.'(. radialin uci-ipiliillialainica
(iratiiileti : /I'VVi'. cortical prnjectinn filires iVdiu the ulolnw pallidiis; HTlit,
lu'iijectioii lilires I'nini tlie anieriiii' part nl' the teuipnral lulie j;niii;j to the
pulvinar (?) : .S/.I7. stratum t;riseuui ceiitrale : ^1!. t'oiinatio reiicularis; Sli,
sillislantia iiinoininata of I^■icllert : sir:, stratum zoiiale: 'I'iii>. cius I'oinicis ;
Til. Ilialamus: Tal. trijinniiin olt'ai'toriiini : I', uncus: Ix/j/i, coruu inl'eiius
of ventriculiis lateralis: II'. Held of Wernicke; XM. findniiifurlifii' llniiluii-
Arcir-KHi) of Meynert ; /c. zona reticularis: //. tract us opticus ; /////. nucleus
N. oculo-inotorii : ///, lila radicularia N. ocnlo-niotorii : .\7/. chia^iiia
opticiim.
the oi)tie fibres it is obvious thtit :i siiijfle tibre must eonie into
contact relation with the cell bodies and dendrites of many
"if I
I
.«
S()2
THE NHKVors SVSTK.M.
iKMironoH of ii liifjlicr onltT. For :i niiniito doscription of the
ttTiiiinals of these fibres the oriirinal iirtieles of these investi-
•Mtors must be consulted.
Fio. aVi. — Lower ])(ii'tioii (if ('(irpiis gciiiciiliitimi latcrulc of a iicwlmrii rat.
(After S. Haiin'iii y Ca.jal, licitra},' /imi Stiiiliimi (h r Meiliilla < )liloiiKata, etc.,
Hresler. Leip/.. ISlMi,' S. KM. Kif;. :it /;. ) .1. olitie (ilires forming' somewhat
llatteued end arliorizatioiis; //, ojitic (ilires teriTiiiiatiiit; in nii(l<lle level; ('
iiiid /'. optic (Hires with ver.v elcisely interwoven end arhori/atioes situated
in the depth; A'. linndU> of eentral optic patli; /•'. lihres continuous with tlie
tractus opticus ; the letter K corresponds to the lower portion of the corxms
Keniciilatuni lalerale.
Von Mouakow believes tliat between tlie terminals of the
fibres of the optic tnict in the lateral genicuhite body and the
cell bodies an<l dendrites of the neurones, the axones of which g^o
u.
GKOUl'ING AND CIIAININT} TOCJETllKU OF XKrUONKS. SO.'}
n of the
investi-
D
liovn cat.
iiifiiitii, etc.,
siiiiicwhiit
lie level : ''
•s situated
IS witli tilt'
tlie ciirpiis
lis of the
y and the
which go
into tlie optic nidiations, (ioljji cells of Type II arc iiitcrcahitcd.
lie thinks that otiuTwisc it is ditticuU to explain the lindings
in cases of liemianopsia.
A certain nunil)er of optic lihres have long hocn known to
stand in intimate reltition to the whiti' nititter of the coUictilus
superior of the corpora (|iiadrigeniina. Thiiiiks to the researches
of Ramon y Cajal * and van Cieluu'htcn,f the proof was hrought
Fio. 513. — G(>\fi\ pre])ariu''>ii fi'diii tlie iiiilviniir of a iiinnse five days did. One
lai'Kt' imiltiiKilar eell, with its axoiie. is visililc. (.M'ter .\. vmi Kolliker.
Haiidlmcli iler ( iewehelelire. I!d. ii, Leipz. lS!Mi. S. oS"), Fif,'. fiitti. > Tlic
tenniiials of the ti'acliis optieiis are visilile.
that the axones which terminate here in tlie superficiid gray
layers are those of optic lihres which have their origin in the
* Ramon y ("iijal, S. Snr la fine striicliii'c dii lobe (i|iti(iiie des nisraii.x
et sur I'cjrijjiiie reelle des iicrfs optiques. [Transl. from Rev. trim, do histol..
1889.] Inteniat. Moiiustolir. f. Aiiat. u. Physiol., Leipz., IJd. viii (1891). S.
337-;i76.
t van Gcluu'litpn, .\. La slriictiirc ilo.s lolies optiqucs cliez romhryoii de
poulet. Cellule, Lierre and Louvain, t. viii (189''), pp. 1-43.
42«
I
Mir
i.ii'f
•i i :
^'l
!'!
804-
TIIH NHIIVOUS SYSTKM.
giin<,'lioii coll layer of the retina. Siiuu! tlioir studies our
kiio\vle(l<,'e of this re^noii has heeii extended by the researehes
of Tartiiferi and Held. Tlie eiidiii<i;.s of the optic fibres sur-
round ^an<,di()ii cells whose axones partly shorter break up in
the su[)erficial j;ray matter immediately on entrance, partly
lonjfer run radially into t!ie dee])er layers of the superior col-
liculiis so as toreaeii the same rcfjjions of the superior colliculus
in wliich terminate many of the libres of the lateral lemniscus.
The difference in si<,niitieance of the superior colliculus for
the optic paths in different aiiinuds has been emphasized espe-
cially by von (iudden * I'ud Hdinger.f In lower forms the optic
lobes — that is, the re<,non of the corpora (|uadri<^emina — are the
main visual organs. In liigiier forms the corpora ((uadrigemina
appear to be tictivo maiidy in reflex functions, while the lateral
geniculate body represents the way station in the visual ])ath to
tiie occipital cortex. In higher mamnuds it seems ])robabl((
that the t)ccipital cortex alone takes part in visual percej)tiou,
for the superior loUiculus can be destroyed without any dis-
turbance of light or color vision. Phylogenetically the superior
colliculus is older than the lateral geniculate body, aiul the
latter in turn than the occipital cortex. In the fish, practically
the whole of the optic nerve ends iii the roof of the midbrain;
in birds, according to Kdinger, one gets a differentiation of a
mesencephalic nucleus (superior colliculus) from a diencephalic
nucleus (lateral geniculate body), and in them for the first lime
one meets with a genuine occipital cortex.
The medial root of the o])tic tract runs into tlie medial
geniculate body where most of its fibres appear to terminate,
although some, according to Obersteiner, may pass through the
brachium (|uadrigeminum inferius into the colliculus inferior.
This medial root of the optic tract has no connection, as von
(iudden prove(l, with either rt'tina, nor with the optic centres
of the mesencephalon aiu' diencephalon. It consists in the
main of the commissura inferior ((iuddeni), which extends be-
tween the two medial geniculate bodies. It therefore prob-
ably represents a commissure in connection with the auditory
system, for, as will be seen later, the medial geniculatt^ body
*0p. cif.
f K(liiif,'('r, L. Vnrlpsuiifron uchor den Bau der nervOsen Centralorpano.
V. Auttagc, Li'ipz. (181)5), S. 2(18 II.
;:>J
(lUolIMNli AND CHAINING TOOKTIIKll (»F NEllioNKS. yo;,
iin<l llu' inferior folliculiis of tlio coriioru (|iia(lrij,M'iiiina arc iin-
portuiit way stations in tlie auditory conduction path.
This medial root of the optic tract, and the inferior coin-
jiiissure of von (Ju(hh'n, are well isolated by extirpation in the
new-horn of hoth eyes, as lias heen seen ahovo (Fij;. aid).
The view of 1 )arkschewitscli and I'ribytkow,* tluit von
(iudden's coiiiinissure n-presents ii crossed connection of the
medial <i;eniculate body witli the nucleus lentiformis, is suj)-
ported by von Ijcchterow,! but is opposed by other investigators.
In addition to tiie eoiuniissura inferior (luddeni. certain other
bundles of •ibres. some of whicli may be connected with the optic
tract, others not. have to Ije eonsidered Ix-fore we leave tliis poi'tion
of the optic conduction path. These are the coiumissurii su])erior
Meynei'li. the hemisplcric bundle of von (luddeii. the comnussm-a
an.sata of Hannover, the commissura hypothalamica anterior, and
the tractus peduncuhiris ti-ansversus.
The colli III issnra superior Mci/iicrfi has been described i)y Mey-
nert.+ Fca'cl,** and von (iuddeii. || In the middle line in the rabbit
it lies almost doi-sal from the optic chiasm. It then descentls ven-
trally and becomes visible lateral fi-om the optic tract, first looking
nai'row. and then becominji: bi'oader. It <'an be followed lalei-al-
ward as far as the junction (jf the medial and lateral part of the
ba.se of the cerebral pedun<de, where it vanishes from vi«'\v (von
Cindden). In human beiiiffs it is never visible except in sections,
l»ut in general the relations are the same (Ki<rs. .')1 1 and .'il.')).
Sclinopfhayen helped to confuse investij^atoi's in that he desiffuated
Meynerts connnissun' as the inferior conunissure. The term com-
missuiM superior shoidd be api)lie<l t() Meynert's comnnssure, and
the term commissura inferioi- should be reserved for the commissure
of von (fudden. The ultimate terndnation of the fibres of Meynert's
commissure is as yet not known. According; to Darkschewitsch and
I'ribytkow the conmiissura superior Meynerti repi'csents a tract
connectin<r the nutdeus lentifornds of one side with the nucleus
* Dnrksclicwitseh. Ij., und G. Pribytkow. Uebor die Pasersystenie tun
IJodcn (ii's (Irittcii llirnvcntrikcls. Neurol. Ceutrullil., Lrijiz., Hd. x (1H!)1),
S. 417-4',>!».
•f von Hcclitt'ivw, W. Die bciliuif^sliiilmen iiii (icliirii uiid Uiiekciunark.
Lcipz. (18!»4). S. 1():{.
X Mcynert. T. Strieker's IhoiiUiueii, iv I.ief., S. 7:!'2.
* Forel, A. UntersiiehuiiKeii iilier die Ii!iul)etire};ion uiid ihre ohureu
Verkiiiipfuiifjen im Geliirne des Meiischeii uikI einiger Siiutrcthiere, iiiit Bei-
tviigeii 7.11 den ^letlioden der (ieliiriuuitersuchung. .Vrcli. f. I'sycliiiit. und
Nervenkr., Herl., Md. vii (1S7T). S. 4H1.
8 Op. eit.
•1 ,
'.i
'If
iir
I.'
1.1 :(
II
1 .■.:
1 L
' mn
il 1
1
jVfj'
«
it
. ;'/
:i
n
80(;
THE NKUVUL'S SYSTEM.
liypollialaniicus (corpus Luysi) of tlu' opposite si(l(>, wliik' Flochsif,'
assuiiM's tliat it i'( presents a deciissatioii between tlie medial lem
niseiis of tlie twosidos. Tiiese theories of its nature are contradicted
by the results of Muhaitn's investiffations of secondary dejfenerii-
tions in huniun beings.*
! f
f
Fl(}. 514.— Tiiuisvcrsc section of ii iioriii.il Imiiiini o|itic cliiiisni alutut the iiiiddlo.
(.\l'lcrl5. VdiHiiiddcii, ( icsiumncltc iiiid llitilciliissciic AMiiindliiii^'. (iraslicv,
Wicsl)., l.S.S!l. TmI'. xix, \'\)i. :>(). I /;. '/'.(•.. Iiiiiidir to Ihc IiiImt cim riMiiii ; ('h.
i-liiasiuii optii'iuii ; i'.M., coiuiiiis.surii siiiHrim- .Mcyiifrti.
acal
Flfi. .^I.'i, — Section from tlie >)rain of a child tlire(> months ohl. Wei^'eit
|)re|ia ration. lAfler W. von Hechterew, Die I.eitniifjsltaiinen ini (ieliirn
Kiickenniark. Deiitscli von !{. \Veinher«. II. Aiill.. Leip/., ISilit, .S. ;>o:5.
174. > v.cal, corpns callosuni ; eh, cliiasnia o|)ticiun: ci. eapsiila interna;
coniniissiira sniHTior .Aleynerti ; cxI, niK lens liyiiotlialaniicus (corpns laiy
((/), },'toliiis pallidns: y')M', filires from the iniclens rulier and the contiinia
of the hrnehiiun coiijiinetiviiiu to the ^'loliiis ]ialli<lus and to the thalan
tl, ta'tiia tiialanii ; //•», tractus optii'iis ; I'li,, ventrieuliis tertiiis.
-Pal
inid
Fij;.
c.V,
si) :
tion
nis ;
* Mahaim, Albert. Ein Fall von sceiuidiiren Erkrnnkuiig dcs Thalamus
opti(!us und dor Rogio subthalainicu. Arch. f. Psyeliiat. und Nervenkr.. Bd.
XXV (1893), S. 34;i-383.
GK()U1MN(J ANM) ('MAlNlNd TOdl'VI'IIKIi (>K NKIIIONKS. S()7
rH-B
Till" lirniisiiht'ric Iinmllc of rnn (]ii(hh')i * 1h> (loscribcs as a
hiiiidlc of lilnTs ill tlic optic tract wliidi ^'ocs uwv to llic most liit-
(Tiil part of tli« base of tlic pcdiinclc. that portion of i\w jx's wliicli
lies nearest to tli«' traetiis opticus, and tlieiicc enters tlie (M-reliral
heinispliere. Tliis bniidle. von (iuddeii staled, does not atropliy on
extirpation of the eyes, liut disa|)pears after I'xtirpation of the cere-
bral hemisphere. H<MMtes espc^cially
tlie experiment of (raiiser, who in the
new-born ral)bit destroyed tiie cliiasm
and tlie commissiira inferior (}nddeni,
thns leadin;^ to complete atropliy of
the correspomliiiff jiarts of the optic
tract and leavinjyf the hemispheric
l>undi<' uninjured and completely iso-
lated (l""ij,''. rilCi). Since tliese stndi(>s
of von (iiiddeii and (ians<"r, however,
but littlelias beiMi added tooiir knowl-
edge of this bundle.
Under tin; name of tiie i-onniiis-
mtrd (tn>i<tfa ui Hannover von Kcilli-
]<er descrilu'S those line libres seen in
iiori/.ontal sections tlii'oii<,''li the chiasm
cut transversely and oblitpiely on its
anterior border. In .saj;fittal sections
one can make out that these (ibrcs
descend from the lamina cinerea ter-
minalis and from the gyrus subcul-
losus. Some authors have thoui^ht
that they are continued into tlie optic
nerve.
The cnmiuissin-d hifpoflKtlnniicn
anterior (the imndle d(!sij>'iialt'd by
von Guddeii as B. T. c.) was lirst
named hy Ganser the decussatio subthalamica anterior. Acconhiij,^
to von Kolliker it runs dorsalward lateral from the columns of
the fornix and then becomes lost in the<itlier lilire bundles running
in the same direction (ansa lenticuiaris, inferior peduncle of the
thalamus and portions of the stria medullaris) (Fig. 517).
The frdctn-s pcdntinilnriH fnnisrrrmis. according to von Tiud-
<\('n, is a bundle beginning in front of the superior colliculus and
running oblicjuely over the base of the cerebral peduncle, turning
around its nu'dial border to sink into the bast^ of the brain in front
of the region of exit of the nervus oculo-motorius. Von (iudden
.stated that it atrojihied entirely in the rabbit after removal of
.")!(). — IJrniii "f r;\l)l(it upcr-
ulcd il|Hin li.v (iMns( T. One eye
WMs ifiiKivt'd iind tlic tractiis
ii|ili('iis near llic iiiiildlc liiii'
t(irii acniss. In this wa.v vnii
(■ilildi'n's lu'iiiisplici'ir hniidli'
of the ip|>tic liact was i.siilattcl
asa liaiiil (if while niatlcr wiiii'ii
passes fioill tile sllll'aee iif till'
nirpils ;.'<'! lien hit mil lati nile into
the hasis pedniiellli. ( After I!.
von (iiidilen, ( iesaninielte nnd
llinlei'lassene .VhhaiiiHnntien.
(hashiy. W'iesl.., is.sit, Taf.
xxix. Via. ~- ' II. II., lieinis-
])lierie hiindlc of the tractiis
ol)tieiis.
* von Giulden, B. Op. cil.
5:$
IW:
!(■; I !'
Ki^ '
m
8(18
TIIK NKIfVors SYSTEM.
Imlli (>y<'s. Its si<;iiilicaiic<' is, however, as yet l>iit iiii|M'i'fe<'tly
tiinlersti)M(l. Tlic l)est recent (leseriptioii is lliat n( voii Kiilli-
Uer,* who (iiids tiiree tra<'tiis peduiieiilares trajisv«'rsi on eacli
sitle ill the raliliit a main liiiiidle and two accessory handles.
This aiithoi' states that tiie main hiindh' arises from a small round
Fl<i. 517. — Frontiil scctmii tliniu^'li llic Iiiihimii liyiHilliiilMiiiiis. Wcincrt staining.
(AI'liT A villi KiilliUir, ILimlliiirli ilcr ( iiwiliililirc, I'.il. ii, l.ciiiz., Isuii, S.
"I'li, i'i^'. tisii. I .1/. iiiisi liiitiiMilMiis : Cn. (■iiiMiiii>siii:i iiiilcriiir cficliri ; Cf,
I'liliiiiiiia I'liniicis : r/iii, I'liiiiiiiissii M liy|iiitliMl.'iiiii('u Miitcrinr; fV. riiiisiiia in-
trfim : ''ill, rdiiiniis^iiiii siiiniinr Mcym rli ; ^^ i.'iiiif;liiiii (i|i|iriiiii liasali' ; Sap,
niirliiis aiisii' pciliiiiriilaris : /'/i. Imsis pidmiriili : si'i, stilus inCriiur llmliiiiii ;
'/'/(, tliMhiiiiiis ; Tr.ii, tr:ii tils updciis ; /, //, IJl. .iiiilciis Itiitil'iiriuis.
nucleus whicii lies lateral ward from the nucleus ruber at the
ventral end of the nucleus l;iteralis posterior thalanii of Nissl.
He liclieves tiiat the liundle terminates in the superioi- collicu'MS of
the cor|iora (luadrifremina. jirohahly in its deeper layers. Von iech-
terew + dei'ives the hiindlo from a small ohlonjr conical ma.ss of
ffray matter which lies lietweiMi the nucleus ruber and the sub-
stantia nigra which he calls the nucleus tractus peduncularis
transversi.
Wo may next properly consider the coll bodies and den-
drites of the nouroiics (optic neurones of tlio III Order) iji the
centres in which the retinal fibres tonninute and trace the
distribution of their axones.
The ri)llici(his sK/wrior of the corpora quadrifjomina, so
larjijely developed in lower animals, is hut rudimojitary in man.
On section one can make out in it a distinct stratum zoniik' on
* <>it. cif., s. cm IT.
+ Op. cif., S. ").
M-rfcctly
11 Kiilli-
ui\ nich
Idintllfs.
ill rnllllll
crt staininR.
ip/., IsiHi. S.
citcliii ; (/,
;. liii'sulii in-
hasiilc: .V";'.
•ii.r lliiilaiui ;
•r ut the
li of Nissl.
.llicuVisof
3ec-li-
oll
ll IIIJISS t)f
h till" siib-
Icluuculuris
and don-
.>r) in tlio
truce
the
h'lninii, so
k- in man.
zoiuilo on
(}U()U1'IN(} AN'I) CIIAININd ToolVrilKIf (iK NKIUONKS. S(li>
tho surface l)eneath wliich is tlie stratiitn ;friseiiiii coUiciili supe-
rioris, wliich in turn is separated from tiie stratmii jrrisi-imi ci'ii-
tralo (the so-caUed ifiilrnlf //i'l/i/rtii/nin of the (ieriiiaiis) hy the
stratum alhiim profundiiiii. 'Die •reiierul dis|iosition of white
and {^ray matter in tiie superior collieuliis will he deirest if we
refer to sections tlirouj^li this hody in the rahltit.
'The stratum zoiude consists of a thin peripheral layer of
white til)res (voii Kidliker's (iriissn-r trriftsc Likji).
The stratum j^riseum coUiculi superioris can he subdivided
into several layers, amoni,' which is to he seen the so-called mid-
dle white matter (von Kollikcr's milllvn' /rn'ssr Ldijc) of the
superior colliculus, which nuiy with propriety he designated
the stratum album nu'dium. These white llbres assume an
antero-i)osterior direction, and are in lar^'e part termiiuds of
ojttic til»res which have entered the colliculus superior by way
of the brachium <piadri;^feniinum supcrius. The su[»crlicial layer
of <,'ray suhstimce, which I shall call the stratum j^riseum super-
liciide, is imrrow, contains relatively few jfanj^dion (H'Hs, and is
of rather small size. This is the so-called cappa cinerea of the
su[)erior colliculus (veil Kidliker's tn'iiKsrrr f/rain' Xniir).
The stratum «friseuin profundum contains a relatively larj^e
number of nerve cells, many of which arc of very larj^e size.
Tho medidlaled axones of these help to form tho stratum album
profundum.
\'on Kiillikcr describes the ufray matter between the stratum
album medium and the stratum album profundum as tho
"■middle <;ray zone," reservinj,' the term "deep <rray zone"
for the fjray imitter in anionjf the supt-rlicial and dei'p fibres
of the stratum album profuuduju (Fi^'. i>\S). In the nomen-
clature of Tartuferi, the stratum album medium plus the
middle gray zone of von KoUiker becomi' the slrahi hinnri)-
rinereo Kiiprrfiridli', while the stratum album profundum with
its fjray matter is desij^nated by him the s/rn/o hidiifn-riiirrni
pi'dj II 11(1(1.
According to Ramon y Cajul, tho most important optic
fibres ending in the superior colliculus come from the zoiu' of
antero-posterior medullated nerve fibres, desigmited above as
the stratum album medium (Tartuferi's stnilo hidiicd-iiiirreo
.sit/wrtirifi/r), whi(d» lies beneath the peripheral gray cortex.
.Vpparently the fibres of the stratum zonale are not direct con-
tinuations of optic tihres, since after extirpation of the eye no
3;!. vVi.
m^
i^.. -. ._^.^|Hj.^ -,
31!' • >
SIO
THK NKllVors SVSTKM,
(It'^oiienitioii of tlioso iibrcs can be (UMnoiistViitod l)y Miirchi's
motliod. KaiiKin y Ciijal suj^ujcsts that tlicy roprcsciit eud
, Pern /
fin DB
l''l(i. 5|S. — Kridital section tliroUKli the colliciiliis siipcriorof tlic ralOiit. StuiiiiiiK
hy \V(i,i;crt's inctliod. (At'tcrA. von Kcillikcr. Ihuidlmcli dcr (icwctx'lt'lirc,
Itil. ii. Lcip/.., ISIH). S. Ul. \'\\i.. T)?!. Tio-. si niCiiii i;risiMiiii cciiIimIc willi
iiniiiitc lilurs .Mill I'iiilial (ilircs: (/, Mi|Urcliiilils (•cicliii ; />/>', (Iccussiilio liiMcliii
I'liiijiiiii'tivi : /'Y. rasciciiliis iii'iliuKiilo-iiiMiiiiiiilliiris. pais t('<;iii('iilalis, in
li-aiisvctsc scclinn ; Wn>. jjanKlioii iiilcipidiinculan' : /, i/i. Iiimiisciis incdialis ;
A'/-, iiindciis nilicr; I'vm. rasciciiliis pcdunciilo-niaiiMiiillaiis. pars liasilaiis
I pc(liMi('iiliis ciirpdiis nianiniillaris) ; /.'/). l>asis pidiiiiciili ; Qi\. (iilliciiiiis
superior ; N((, siilistantia iiittra ; ///. iiiirlcus N. cHiilo-niotorii, with its rout
liliii's; ;//•, ;/(•', i/i''', gray layers 4>l' tin- eollit'liltls superior; »', /(•■■', \r^, wliile
zones.
arl)orizati()iis of axonos which arise from cells in the cortex of
tlie c()lli(Uilus itself. -
In the rappa chiPt'iut of Tartuferi, l)esidea the small ctmical
stellate or spindle-shaped cells described there by Tartuferi and
HiJiKi' u'
(iUori'INd AND CHAININM; T(>(tKTlll-R «il>' NKllJONKS. j,) 1
I'. Tlainou y C'iijal,* S. IJaiiinn y Cajal describes certain other
cell types: {(/) iiiar<j:iiial cells, (//) horizontal spiiiille-sha}>e(l
eells, (r) small cells with demlrites tlireeted outward.
Kio. 519. — Tniiisvi'rso sccliiin tlir(iii<:li tlic rollicMilus siipcriDr (if a r;il>l>it cifitit
(lays (lid. (.Vt'tcr S. IvaiiK'ni y Cajal, licitrau zmii Stu(iim;i dcr Medulla
OliIdUKata. clc. iti'cslcr, LcipV... ISiMi, S. :iO, I'Mji. 7. ) .1. siii-racc at middle
line: />'. hiniiiia tri'isea suiierlicialis Crartuleri's citpiia ciiierea ' ; ('. layer ol'
(ip(ie tilires ; I), layer (if (Hires nniiiiiiK Iraiisversely i 'PartliCeri's stralo-
liiaucdciiiereo proCuiido : <(. iiiar;jiiial cells; /), liorizdiilal spindle cells; r,
sanit" kind of cell with well-marked axoiie; <l. small cell willi cdiiiplieated
(l"tidriles; c, vertical sjiindle cells; /, ij. h, dill'erent t.vpes of cells of the uray
l.iyer ; J.li, spindle-shaped types of cells of the optic layi'r ; .1/. /„ cells of the
layer of transverse tihres; in. collateral descending toward tile .stratum
t,'ri,<eiiiii eentrale ;, «, end arhorization of an optic tihre.
The axoties of the small marijiiial cells (Fij;. 510, a) are
delictite; thev run downward, liut their tcrniination is imccr-
Icoiticai
* Hmiuui y Ciijiil, P. Iiivcstigacioiies ilt; hist(il(i,i;ia coinpiii'iKla on los
(viitros (le III vision <ln dislintos vertnlinidos, 1800; liiveslipieioiii's mioro-
f^raficiis en el ciicefalo de los liafnicios y reptiles, ciieriios i;piiieulailos y
(nl)orcnlos ciiiulrif^iMniiios <ie los inatiiiferos. Zaraj;oza, \H[)i.
i>
\\m
^'
•i
812
THE NERVOUS SYSTEM.
tiiin. Till' spiiidlc-sliiipi'd cells pliiccd panilU'l to the siirfjiec
of the colliculus show [)olar di'iKlrites, two or three in niiinher,
Avliich run horizontally, divide once or twice dichotoiuously, and
end with free, somewhat jii<;<,'ed terminals (Fi^'. 51'.), /j). Their
axones usually arise from the dendrites and also run horizon-
tally, soon breakin<f up into a number of small branches which
lire distributed in the first layer. They ap])ear to be (lolj^n
cells of type II. The small cells with dendrites directed out-
ward are triangular, ovoid, or stellate in sha])e. They ])ossess
from one to tliree or more di'iidrites, which, ])ranchin<f mani-
foldly, form an irrejjfular conii)lex l)undle of delicate tortuous
terminals. The dendrites are so delicate that they mifjht be
taken for axones. The a.\ones, however, descend ; they are
short, but little branclied, anti reach as far as the zone of optic
or antero-posterior fibres (Fig. 51!), (I).
The ending of the optic fibres has already been described.
The axones of the large nerve cells of the stratum griseum pro-
fundum and in the stratum album profundum itself pass ven-
tralward in the stratum album profundum, beiuling around tlie
gray nuitter which surrounds tiie central canal, and giving otf
in their course collaterals to the adjacent gray matter. As
they curve they often underjro T-shaped division, one branch
passing dorsalward, the other ventralward, the dorsal branches
terminating, as a rule, soon after their origin, a few of them
passing, however, to the superior colliculus of the op])osite side.
The ventral branches, along with the undivided axones, imite
to form the curved system of fibres which run along the margin
of the central gray matter (Ileltl). The.se arched fibres pass
ventral to the fasinculus longitudinalis medialis and nucleus 2s.
oculo-motorii as far as the mid<llc line, where tliey decus.sate, as
Held has shown, with similar fibres from the opposite side in
what Forel has called the '•\fotit<ti Heart igv Ildiif/c/i/.-reitztnii/ of
.Meynert." The fibres then pass downward toward the medulla,
and in human beings soon enter into the fasciculus longitudi-
nalis medialis. In cats and rats Held found it forming a sepa-
rate bundle from the fasciculus longitudinalis medialis for
some distance. As these axones pass downward they give off,
from (litTerent regions, collaterals and termimds to the various
motor nuclei which innervate the eye muscles, a fact which
accounts for the eye muscle reflexes which result from retinal
stimulation. The superior coUiculi of the corpora quadri-
GUOUPIN(i AXI) CIIAIXING T(X}HTIIK1{ OF NKl'IJoNKS. si;]
gemiiiii iippoiir to represent the central organ concerned in ihe
control of the eye-iiiusclc movements.
C
The forjiKs ///■i/iiii/(f/tiiii ht/rrn/r is a part of the metathala-
mu.5 of till' tlialamt'iicephaloii. It, together with tlie pulvinar
Ki(i. .Wi). — Sclicm;ili<' Crciiilil scrtinii tlii(iiij,'li the iii'ciiiiuil liilii-. ( Al'lrr If.
Siiclis. Das Ili'iir ■.pli.iri'iiiiiiiik <li's .Mcnschliclicii ( ii(ps>liinis, I. |)i r Iliiilir-
lmii|)llaii|"ii. licip/.., 1S!):>, S. (i. Fie 3. ) r. ciiniii posti riiis vciitiiriili latiTMli-;
/.(•., lissui.i cMlcariiiii : s, uiipci' clivi>ii)ii ; ('. Iciwcr divisiini; (((//.sulcus icil-
latcralis: s.a.l. sulcus nccipilalis supcriiu- (issura iutcipaiictalis ; s.n.lf.
sulcus occipitalis uicilius ; s.n. Ill, sulcus iiccipilalis iiil'crior ; <\ii.. calcar avis ;
<;./., fiyrus liufjualis ; ()../'., fiyrus I'usit'iuuiis : ii.n.s.. uyriis occipitalis supcrinr:
(1.0. m.. fjyrus occipitalis lucdius; ii.a.i., ;ryius occipitalis iul'ciior: c. cuucus;
/ /", forceps: ll-I'i. stratum saj;iltalc intcruuiu ; I'l. stialuui sairittalc cx-
tcniuiii : I'i. stratuui calcariiiuiu : /,', stratuui < unci tiausvcisuui : Z.^'. stratiiui
proiuiuiii cuiici ; /.''. snatuui propiiuui s.n.l: .'ii, stratuui pinpiiuui s.u.ll: .'I.
stratum proprium .•.•.((./// : .'.'. >tratuui prciprium .v.co//. ; .'.;, stratum pinluuilum
<'ouvt'xitatis.
,b
^ii
>i i i << I
HI!'
M4
TlIK NKKVOl'S SVSTIOM.
of tlio thiiliuniis, rcprosonts the main tonniiiiitioii of optic
lihrc's in tlic (liciiccplialoii. 'IMic ^'ciicral clianictcrs of the
later; ! ^cnitniliito body liavc alrcudy bei'ii dcscrilx'vi {rit/c su/ira).
The gray nuitter inside tlie lateral "cjiiculate body in buman
beings is known as tbe nueleus corporis genieulati lateralis.
The majority of the ce'ls situated here ])ossess axones which
run out tiirough the radiatio occipito-thalamica ((Jratiolcti) to
Lobulus puriitnliH suin'rior.
Sulcus cinijuli,
(iyrus ciiKjuU.
SftU'iiiiim coi lion's (
fiilliisi. )
Piilvinitr.
Corpus genicuUttutii
meiUnlr.
Finsura hiiipocampi. ■
Trill t us iiiiticHS. ■
.Sulcus iaIciiiiiiUtulis.
TcrniiiKttion of opt
Corpus gctiiculat
(I
' Lohuln.i piirietolis infirinr.
Fissiira ccrihri lateiiilis
[Sylrii].
(li/riis sujinimoriii-
itiilis.
Sulcus linijiordlis
supi'ti'ir.
(,'!/nis limporolis
mi'iliiis.
Sulcus temporalis ntedius.
yrus
ippornmpi. ;
Gyrus liiuiiKtlis. .'
II yrus fusiformis.
(tyrus teiiiponitis inferior.
Riiiliiitio corporis (/c/iic. hit.
A r.-'..? Ami supplicil hy iirteria ccrrliri iiicilia
B MB Area supiilieil by arteria cerebri po.iterior.
C (Unstippled) Area supplied liy arteria cerebri anterior.
Fm. 5!il. — Froiitiil section of liimmii bruin, illustnitint; the visual ('(nKliictidii patli.
(Al't^'rC. voii Monaivdw, (iciiinipatliolonic, Wicn. 1S!I7. S. )>',i. Fifi- I<>. )
terminate in the cortex of the occipital lobe of the hemisphere.
The medulhited axones extending between the lateral genicu-
late body and the cortex pass at first lateral from the lateral
geniculate body and form an area known as Wernicke's field.*
The fibres are joined by others from the pulvinar and from the
colliculufi superior of the (Corpora (piadrigemina. They then
turn around the nucleus caudatus and the lamina semicircularis
and enter the optic radiation, (iratiolefs radiation forms u
* von Moimkow calls this " dit.s laterale Mark" of the liitoral gciiicnlato
body.
pi""
OUoriMNO AND ClIAININd T<»(iKTIIHU dF XKrUoNHS. j^l5
large sujjittal bundle {sinihnii siKjithilc inftrttinn of Sachs,*
Kig, A'^O), which runs all the way hack, dorsal and hiteral, from
tlie cornii posteritis of the lateral ventricle to the cuneiis.
'JMie white matter of this region includes the tapetum, the
genuine optic radiations, and the so-called fasciculus longitu-
diiuilis inferior. The "elations of these bundles to one another
are well shown in the accompanying diagrams (Figs. 5"^1, 5*^2,
and r)'^:5), selected from von Monakow. The medulhited axones
from the lateral geniculate body are situated in tlie occipito-
thalamic radiaticms, ventral from those arising in the pulvinar.
As the fibres extend toward the occipital pole, those arising in
the lateral geniculate body tend to become distributed to the
IaiIiuIiis jutiietitlis 8Uiiriu<ir. i
SuUvn riiKjiili
Si)l(itiiim iiii'iiDfin \" ,' ""^'J^
lalloHi. I — :' .rr'-'
Tapetum. -
Fissn rti h ippitrn mpi
Gyrus hippocampi. , --
(Ij/ius fiisifdniii.i
I iiitrriiiiiivtalis.
Liihitlnn pariitalis iiifcriur.
Fiasvrn cvrrhri lale-
rtilin \,si/lrii\.
. FiiKcicultta loiKiihidi-
tiiilin inferior.
- (,'yru.i siipiuininiiiiinli.i.
-■ liiidiittid <>ci'ipiU>llitila-
iiiiiii [(,'iiiti<iliti\.
-■ '^•iliitu tempiiniUs supe-
rior.
I — 'Jyriis ttitiporali.'i umiiiis.
Gyrus timinirdlis inferior.
A TV'X'i Are)i supplied liy artrria cerebri media.
B MH Area supplied by arleria cerebri pnshrior.
C (l!iistil>pied) Area supplied by arteria ciribri autcriar.
Vui. !>22. — Froiiliil section of iiornial limiian liniiii. illtislmliiit; occipilo-tluiliiniic
mdiatioii, etc. ( Al'tt'r ('. von Monakow, (icliirn])atlioloi;ic, Wicii. lSi(7. S.
2!.', V\ii. li.)
medial surface of the hemisphere, especially to the cuneus in
the region of the calcarine lissure (Fig. 5^4).
* Sa(!hs. 11. Das llcmispluirciunark dos inonscliliclieti (Jrosshirns. 1.
Der Ilinterhauptlappcii. Arb. a. d. psycliial. Kliiiik in Hrcslaii. Lfi[izif;
(1802).
810
TUK NHUVOUS SVSTKM.
A HupcM'l) (lenioiistration of the exact ])()sitioii of tho axonos
from tlie cells in the latenil ^'eiuciilate body is atTordcd liy liori-
zoiital sections tliroii<;li the l)raiii of a newborn balu'. At this
age, as Flechsig has shown, tluse fibres are niedullate*!, while all
the other fibres of (Jratiolet's radiatioji are as yet non-niedul-
late<l, and one can follow then as a very definite bnndle passing
out fan-shai)ed from the posterior sui)erior lateral surface back-
ward as far as the wall of the ventricb', and upward almost to
the ui)per border of the thalamus. This bundle has been called
by Flechsig * the "optic radiation in the narrower .'\'nse" to
distinguish it from (Iratiolet's radiation, or the "optic radiation
in the wider sense." I''lechsig feels suri that the axones from
tlie lateral geniculate body (" optic radiation in the narrower
sense") end exclusively in the wall of the fissura calcarina
ni^
Lobiiliis iKtriitutin siiiivrior
Prdiuiieiis.
Fi-imirn jiririeto -■
ovciiiittilin.
TdjM'titm. -
Fi-isiini citlntriiiii.
Cdlciir (ii'is. --
dj/nis Ihiijitolin. ''
(ri/rns mrijiitii-tiuiiioniliK. ■''
Siili'us ill fvrixifiitiilis
.. (j'l/nis iiiiijiiliiiis
— Riiiliiitii) orri/)iti)-tliiiliiiuirn
[(lllltin\vti].
— ynmiriihis liiiiiiilinliiKilis
iiijrrinr.
(Ii/i'i iicciliitiiU'S.
A fi:!:i Areii siqipUeil hi/ nrte'-iit reri'hri imiliii.
B am. Inn siiiiiilicil hy iirtfi-iii cvrihri iioatcri'ir.
C H'listiiiiilfd) Ann sujiiiliiil hij (irtt'iiri vrrehri fiiitcriiir.
Ki(i. iW;}.— Frontal section of normal human l>raiii, illustratiiifr occiiiito-tlialaniii'
radiation, etc. lAI'tcrC. von .M<inako\v. (icliirnpatlioloL'ii', Wicn, 18!I7 S
20, Fi},'. 10. )
(Fig. b-iiS). lie assumes, further, that tliese fibres represent
the indirect continutitious of the fil)res from the macuhi lutea.
If he be correct, the clinical significance of tlie fact is obvious.
Hy the study of secondary degenerations the relation exist-
ing between the hiteral geniculate l)ody and the cortex lias
* Flechsig, P. Gcliirn und Socle, ii. Aufl., Leipz. (1896), Anm. 29, S. 72.
V
GROL'PIXd AM) CHAINING TOGirniEU OF NKL'IIONKS. SI 7
been witU illustnitod. N'oii Muiiakow lias shown thai in K'sions
of tlio ofcipital cortex in man involving tlio region in wliitli
the occipito-thalaniic regions terniinato, there results degenera-
tion, with aljsorption, of the radiation of tlio hiteral genieuhite
_cq cr
r\ .
Ccl
'•' Co»
Ta,, Cgl c, ccb
Firi. .Wl. — Posterior i);irt of left ccrchrnl liciiiisidicrc ; iiit(li;il siiiImcc. Tlic
scptiiiii luciiliiin liMs lii'cii i-('iiiovi(l aii<l the |m(Iiiii(u1ii> rirchri ciil lliroiiyli
close to llif lli;il;iiiiiis. Al'ltr ,1. lli'iilc, llimillmcli ili'r Ni ivciilriirf (irs
Mi'ns<'li('ii, II. Aiill.. Itnimiscli., Is7!(, S. isii. V'\<i. 1((."). ) r. ciiinus; Crn, cor-
l)iis iii;uiiiiiill;n'i' : fW), cross scrtioii of iMiliiiiculiis cenUri ; re/, coridis ciil-
losuiii ; T;;/. corims Kiiii(iil;itmii liilcnili' : Ox;, coimnissurii aiitcrior cercliri ;
Ti/, (•<illiciiliis suiicrior; r.s, corims striatiiiii ihhIcus ciiiidiitiis ; I'll. fascia
(Iciilata ; I'i. (iiiil)ria ; /•'()//. (issiira cal<ariiia ; /•'«/). tissina iiariclo-oici|iilalis;
'.'(', Ky'i^- lintjiili ; i<li. K.vriis liiiipocainiii ; '.7/, uncus: I'ir. praMinicus ; Sn.
suhslaiitia ui^ra ; '/'"/), iipcluin ; 7'//, llialanius; VV, tulHi'culiini autcrius
tlialaiui ; /, tractus olfaclorius ; //, ucrs us opticus.
L
tlialaiiiic
IS'tr. S,
)resent
lutea.
ivious.
11 exist-
'X llilS
body, and the ganglion cells of the lateral geniculate body
atrophy, !Uid finally disappear (Fig. 5t>(;). Von Monakow has
further shown, liy repetited exiieriinents on animals, that extir-
pation of the visual sense area of the cortex leads to degenera-
tion and disappearance of the majority of the ganglion cells of
the lateral geniculate body. The changes in the lateral genicu-
late body under these conditions are in nnirked contrast with
those which occur when the optic tract is diseased or experi-
mentally cut. Whereas, in the former case, it is the gandion
cells of the lateral geniculate body and the white mat . r of
; :\
1
I I' ■;
( . ■
xi'
if.
■■;v„»'f
\v:\.
.J
S18
TIIK NKUVOlS SVSTKM.
WiTiiickc's licld wliicli (U'«(('ii('nit(', in \.\w latter instanco tlio
;^iin<,'li()ii cells and the white iiiatler of \\'eriiieke'.s field iiro
AKsttriiitio)! rciitr*' of
Jroutiil lulif.
siiiniiiir.
Assitriittion
triiijxinil ^^
liihv. \
Unriiiiijihtili/
ili-vt'loped.)
h'ddiiilio ocii'iiilo th
Sfluilfn/i'irtiiiiifr Ki'ir/ii r of
.^ Fit'iliKKj (iiiil r. Tsiliini'li.
J .Vi/c/i'Ks Idtmili.i Ihiiliitni.
.> (lutff iiii'iliiiu of I.iiy.i.
Collimhis HUjirriiir corp.
(/Had.
Thol(inm.i.
I'isiiitl .sense arm.
Kl(;..Wr>. — Hori/.iiiital section frorii the Itr.iiii (ifa cliild in the spcond week of life.
( Aft*'!- I'. Fli'ciisiK, (ifiiirn und Scfic, Lcip/.., 1890, Taf. iii, Fig. 4. ; (', nucleus
ciiwdatus ; /', putuiniMi ; (lyp, globus pallidum.
practically uninjured, but the fibres of the optic tract and their
terniiiiiils (substantia f^elatinosa of the lateral geniculate body)
vanish.
The region of the jiulvintir in which the opticvtract fibres
terniiuiite resembles very closely in its histological appearances
the lateral geniculate body. The cell bodies situated here give
off axones which enter the radiatio occi]»ito-thalaniica f (Jratio-
leti] in a plane dorsal from that occupied by the medullatcd
axones from the lateral geniculate body.
I
(!l{<»ri'l\(i AM) CIIAIXIXn TOOKTriKK OK N'KI'IJONKS. slf»
ik of lift",
iniclius
As t<» the I'xistiMicc in mini <>l" iiciiroiifs witli cell bodies
sitimtcd in tiic colliciiliis superior and axoiics extending to the
visual sense area in tiie occipital cortex, there is, iis yt't, some
doniit, althou;;h the tindinjfs in the superior e(»llicuius, after
disease of the visual sense area, would lead one to helieve that
at least a certain niind)er of sueh lu'urones exist. It is proitahle
that the cell bodies of these neurones are situated in the stratum
(friseum collicidi superioris, and that the axoiics p;iss i)y wav of
the brachium (|nadrijremiiium sui)erius and t he radiatio oecipito-
thahunica to the cortex. Just what impulses are carrii'd i)y
W:^.-«i<;
,.S
'll'iU'^.r'l t '1
V
,4P V..-
'H..-.
1)1. r
m^me-
h\. V.
ml
Tntctus
oiiticim.
bl.v.
Xtriijthic trix'tux i>i>tifii.i
Vut. .W(i. — Niiinml mikI (1c<;('iii'riit('il coi-ims K<'"'"'i'l''tiitii latcriilc. 1 After ('. von
Moiiiil<(i\v. (i(liinip;itliolo>.'ic, Wicii, Isst7, S. :i(>(), i'ij.'s. ss mikI so. i A. Nor-
iiimI corpus iiciiiViiliiliiiii iiitcralc 15. Corpus jiciiiriilaliiiii lalcralc, (Ickcii-
crated afti'r fxlcnsivi' lesion in llie Johns leni|ioralis and lohns orcipitalis of
llie left side. ((, masses of small uanj;linn eells arran^id in la.S'ers, shown
atrophic (ml) in I': i», lamina nie<liillares. shown atrophic »i(/) in !>: /), ven-
tral Tnass of larjie elements ; In. 1 laclns opticus : m'. doisal white capsule. In
Via. 15. — (((/, loss of tiaiiKlion cells in the dorsal la.vers ; hil, total deKeneralioii
of the larse eells in the centnil region. The optic tract is atrophic in I'..
these fibres does not yet seem clear, for in inan the stipi-rior
colliculus can be entirely destroyed without any reco<?nizable
disturbance of light or color vision.
I
S'2( »
Till-: N'KlfVors SYS'I'H.M.
(iU(HI'lN(i AND ('!l.\ININ(i TOdK'niKI} oF NKllJoNHS. S'JI
\
lus of !l
IliMlulla
1 /)', Cfll-
||i tilnt'S
lie ; '.',
Iniiniil-
lllliltlllU
riil)l)it.* Riinioii y <'iijal (lirftiiifiuislics n siipiTiicial iind a dt'cp
()|)ti(! piith cxti'iuliii^ from these lowi-r ccMtrcs t(» tlit- uccipilal
cortex.
Tlie siipci'lleial path arises t'ntiii tlie superficial zones (»f tlio
lateral f^oiiicuhito btxly, and periiaps from tlie re^jfioii of tlio
stnituin /onali' of the thalamus. This path accompanies in
part the continuation of the optic tract itself, and liavin;;
arrivetl at the pcduncidus cerein-i, turns medialward in order to
enter into the upper portion of the latter, where a lurj^e tri-
an<,'nlar hundle exists, sometimes separatetl distinctly from tho
other fil)res of the peduncle, a hundle \vhi(di IJamoii y Cajal
calls the "central optic patli " ( Fi^'. .")•.*;).
The dtu^p optic path is niucii more imi)ortant. it collects
tho axis cylindors of the cells lyin;,' deep in the lateral genicu-
late body as well as those of tho stratum zonale, forms a curvo
slij^htly concave laterahvard, and enters tlie "central optic
path " on its medial border.
Some of the axonea entering the " central optic path " un-
dergo bifurcation, one branch ascending with the main bundle
of this path into the corpus striatum, the other descending
toward the tegmentum. Kainon y Cajal suggests that the
(lesi'cnding branches may represent a reflex path between the
visual centres and tho motor nuclei of the eyOvS, of the head,
and of the neck.
It is of tho highest interest and importance that Kamon y
Cajal has been able to follow the ax(»ncs of the "central o]itic
path" in the new-born mouse throughout their entire course,
from their entrance into the corpus striatum as far a.s their
termination in the occipital lobe. Ho describes the bundle as
occupying the most medial part of the ]ieduncular radiation in
its passage through tlii' cor]>us striatum, and states that the
fibres having arrived in the white substanci' beneath the cortex,
go upward into tho gray substa..v;e of those cortical regions in
whi(di tho white stripe of (iennari or Vic(| d'Azyr \ is especially
* Haninii y rajiil, S. Sfrnctiir dcs tluilainus cipficiis. ncitnii,' ziuii Sturii-
11111 (lor Mfiliilla < >l>l(iii,i;alfi di's Ivli'iiiliirns und di-s l'rs|iniiij,'s (Kt Gi'liini-
norvt'ii. Leipz. (IHIMI). S. 101.
t This stripe is also soiiiftiincs railed liiiillMri^er's layer. In the enrtox
of the calcariiic fissure it is split into two hands of white fihres whieli run
parallel to one another, the so-ealled internal and external stripes of
Baillarcer.
'>■;
I Ml
! \
H22 TllK N Kit vol's SYSTKM.
woll (hn'clopcd, u lindi!);,' wliicli iifjroos
entirely with tiuM'tiilirynlo^ficiil ohscrvu-
tioiiH of Flt'cli.si;^r. rnrortiiiiiitcly, tlio
ultiniutc tcnuiimls in the <,'riiy miiticr <»f
the coi'tcx were not iiiiprcjjfinitcd in Uii-
nion y Ciijars prcitiiriiliiuis, possihiy lu'-
ciiusc the tcrtninalrt in the new - born
nions(> had not yet dcvcdopcd. \on
Kiillikcr, in discnssin}; these lindinjis,
linds it striking,' that Uanion y (ajal
has referred all ol" the axones of the cells
whi(di lie in the distrihiition of the
opticus to the centripetal optic path,
especially as it was Uanu'ni y Cajal him-
self who dis(;overed ceiitrifuf^al optic
fibres in mammals, and believed that
he had found such in birds.
Tho structure of the prinuiry visual
sense area in the cerebral cortex — that
is, of the rcfjion in which the fibres of
the (X'cipito- thalamic radiations termi-
nate — has been studied by a nundier of
investijjators. ()n( of the l)eat descrip-
tions is that of S. RauH)!! y Cajal.* Wo
can not do better ])erhaps, in order to
illustrate the extreme coin;)lexity of tlu;
cortex in this rej^ion, than co introduce
here the fi^un? emlxxlyint? ttu> results of
the exact studies of the Swedinli inves-
tigator Ilamnnirberg t (I'^'g- •*)"vH)-
As to the ten:! "nation of the fibres of
the occipito-thalamic radiation in the
cerebral cortex, von ^fonakow believes,
from tlie study of secondary degenera-
II w'
|W-
iV.^
/?
!♦
Lth
* Hiiinon y f'ajai. S. Uobor (1(mi Hiui diT
Itiiulo des unteriMi HinU'rliaiiplliip|)(Mis dor
I-'ir,. 528.— Section tliroii<;li ]<l,.i,„>n Siiiii,M'tlii.-re. Ztsclir. f. wissenscli. Zool.,
the cortex nl tile fj.vnis ■, i ■ • ,,on.), ■■ e^ i
oeci|,iti.lissui,crior. (Aft- "'!• I^' 0^!>.5). Heft 4.
el- ('. llMiiiiMiU'lier},', stii- f !'uiiiiniirl)prjj, C. Stiidier ("ifver I(Hotieiis
.lioiofve.l.liotu.|isKliii- ,.,j i „_,,, ,.,,,„,,( j;;,,,,^, iT,„lersokninpir af
ik ocli I'atoli,;'!. etc., I p ^ ^
siilii, 1S!i:j, Tut", ii, Fi>;. 4.) Iljiirnbarkens Nurinala Anatomi. Uiisiila, 1893.
(lUullMNii AM) ( ll.\l.\IN(i T(><iKTIIi;it (>K NKlUoNKS. ,s:>;;
t.ii»ii!<, tliiit lilt' iiltitiiiitf t'lnl-iirltoriziilioiis cnrrt'spDiHl riiorc pur-
tiiiiliirl)' l(» tlic lihrc plexus of ilic lift,, liiycr, iiiiil in piirt also
to tlu' third anil fourth lay«'rrt. I lent he wctuld place (iol^^i
cells of Tyi"' II, which, l)y ineaiis of their much - hraiiched
axones, transfer the irM|)iilses to the rv\U of the sauu' und other
cortical layers. This view is supported hy the lindinf,'s (»f von
Leoiiowa * ill cases of coji^^'iiilal aM«»phthulniia. On account
of the lar<,'(i nuinl»er of v.dnahlo contrihiitioiis whi(di von Mona-
kow hiis made hy his iiivestij,'ations of the optic paths in man
•ind aninnils, the scheme which lu^ has constructed for the ex-
;>lanalioii (d" the route followed hy the impidses is worthy of
special consideration. It is reproduced in l''i<i[. ^riU.
The area in the* cerehral cortex, in whi(di tho uxones from
the optic centri's iu the mesencephalon and diencephalon ter-
minate, is desi<fnated, as has I)een mentioned aliov., as the vis-
ual sense area {Sr/isji/iiirr of the (lermans). Its (fxact (txtent in
the cortex is us yet the suhject of much dispute. Whereas
Fleehsig, for example, maintains that the lihres of (Iratiolet's
radiation are <listrihuted oidy to the medial surface of the
occipital lohe and to a small area close to the lissnra lon;,ntudi-
nalis cerehri on tlu' lateral surface of the hemisphere, (dhcr
investipitors (imdudinfif H. Sa(dis and (". von iMonakow) helievt'
that fd)reH of tho oecipito-thalamit^ radiations are distrihuted to
tlie whole of the cortex of the occipital lohe, and possildy also to
the posterior ])art of the ]»arietal lolic. It seems certain tliat the
majority of the fibres from the lateral geniculate hody end in the
rci^ion of the calcarine fissure. I'atholof^ical cases in human
bein{i;s thu.s far studied have not been unifornj on()u<,di in tlu ir
results to ])ermit of decisive statements rej,Mrdin<f the matter.
In tho majority of tho cases in which hejniant)psia has resulted
from cortical disease, tho rejjion about tho cahiarino fissure has
been involved, in some instances the posterior part of the fis-
sure to a fjfroa tor extent, in other instances tho anterior part.
Tlu view of Forrier, that the jryrus antfularis represents the
visual (iontro, is opposed by both Flechsi^' and von Monakow.
Certain it is that lesions in the rof?ion of tho anj^ular f^yrus ari",
as a rule, accom))anied by defo(!ts in the visual field, but it
* v()aIjcon()wa,<1. Beit riigozin-Ktimilniss dor socuiKliircii VcriiiiiU'ruiigt'ii
tier primiiren optisclicn ('entn-ii und Haliiu'ii im Kiilleii voii coni^enitiiltM'
Aiio[)litliidnnf und Hn11)usiitri>iiliii' lici iiiMiLrchcirciicu Kitidern. Ardi. I'.
Psychial. u. Nervenkr., H.'il.. lid. xxviii (tSiXi). S. ."iii-KG.
54
Mr
Wn
grgSJoTn^J^-^l Stiiituiii intjiiniili irtinil'.
/.'l)l/» <lll(l ClIIK'd.
MUtler'i fibrrg.
Ml iiiliiiiuii liiiiilitiin i.rttriiu,
h'.i liiiiiil mull III liil/ir.
h'jrtiiiiiil iiiiilifiiliir liiyii:
' hilt rittil iiuclfiir Inyvr.
X. iifjtifu.i
<\il jills ;;( HICK
tlllltlll /lift lu/(
('/'''<' IllllillliilllS
Ihniliiijoiic.y
Thiiii roiiiiiil Ini/i r {iiiiiiit
l>yiii initial iillm.
Flo. ,■)','!•. Siluiiu' 111' ihc visual cipiuluclion patlis. (Al'ttvC von MnnakdW.
( iiliiiii|i;itli<ili(Kii', Wicii. IM17, S. 1 K(, KIr. I'^O, ) n. rcids iinil (((lies ; /(. mils ; c,
iMuIci (if rods ; d. Iiipdlur cclis I'lii- tlic ciiiu's ; c, liipolar ((lis I'di- the nids : /,
lai'Hc inulli|i(ilai' nanjrliDii cells <;iviiif-' •''>*'''" tlic iixoncs ol' the N. (ipliciis ;
;;, (('ntril'ilKiil axoiic of :i iiciircuic, the cell Ixidy of wlii(di is situated in the
(■(illiciilus su]ieriiii', its lilddeiidridii lieiii^ situated in the retina; /i. (icd«i
(•(11 (it'Type 1 1, or dendraxdiie in the ('(U'piis K<'ni(Ulatuin laterale ; i. neurone
cdnnectinf; the corpus Kcniculatuni laterale with the hihus occipitalis, its
axone running; in the radiatio occipito-tliulaiuica (iratioleti '. The visual iiu-
jiulses arc indicated hy the arrow.
ilHto
«il{()l l'IN(i AMI CIIAIMNd 'l'(i(iF/niKli oF NKllCoNKS. Si>:>
sociiis proliiililc lliat in ("Vcry siicli instance tlic li'sioii lias not
l)('('n limited to the <'ortex in the rej^'ion of the an^Milar ;,arns,
hilt has (>\ten(le(l into the white matter henealh and has in-
volved I he tihres ol' t he
radiutio oecipito- thala-
miea((irat ioleti) on their
way to the occipital lolie.
Attempts have heeii
made hy Munk and
others to (•oiineet. certain
areas of the occipital
cortex timet ionally with
definite ri-j^ions of the
rotiim. 'I'hus Munk
would make the lateral
part of the retina corre-
spond to the lateral part
of the visual sense area
in the occipital cortex,
the medial hordcr of the
retina to tlx; medial ])or-
tion of tho cortical area,
and similarly for the up-
per and inferior ])ortions
of the retina. lie he-
lieves that the rej^ion of
the niaciihi lutea is re)>-
resented only in the oj)-
posite visual sense area.
I'ut this view is not
wholly in accord with tlu'
tindinjis in cases of hemi-
anoi)sia. It is rare in in-
stances of homonymous
liemiiinopsia to find de-
fec^t of the visual field
correspond illff to the fix- I'm;. 5:U).— Sclicnic nC a liypnllictiial (l(MMis*«i-
, , , liiiii (if tlu' itxoins iiii>siii« (Viiiii tlir rurpiis
ation point (macula In- ^i.iiiciiiiiiiiui iMinaic lotlir l(ii.ii-...<-.ipiiaiis.
ua). \ at ions in(oti(,>, ,,.,,,|,, >,-,,,.,.,,„^ ,,,, n,,,,,,,!,.. r • .'.i.. i.m.v.,
have heen offered as at- isit?, p. till, I"i«. UT. * /.-).. Idlnisnciipitali^;
.... (•,</, c. corpus ;;cnic'iilatiiiii latcnilc ; c.o.,
tl'inptstoexplain tllispe- llialanms; I., I., lolliciiliisMiprrior.
IN'*"
<■■■■•
li
w
H-2{\
TIIH NHRVors SYSTKAI.
culiiirity of the majority of cases of lieniiajiopsia. Thus vuti
(ieluichten sugf^ests a partial (U'cuissatiou of the opti(! tihres,
extciuliug between the centres in the (iien('e])haIon and the;
occipital cortex (Kig. •')•{()), l)ut this view as yet hutks anatom-
ical support. The explanation of von Monakow is ingenious
if not eniirely satisfactory. This author* assumes that the
inacuila lutea hhres arc very widely distrihuted in the lateral
geniculate body, the fibres from the macula of each side being
distributed in each lateral geniculate body so as to come into
conduction relation with cells in all ])arts of this nucleus (Kig.
o.'Jl). With siu;h an anatomical relation in the lateral genic-
ulate body there could always be a ])ath from the macula to
the cortex unless all the cortical connections with the lateral
geniculate body were destroyed. \'on Monakow, therefore, be-
lieves that the macula lutea is rej)resented in the occipital
lobe, neither solely in the middle nor in the peri])heral ])arts
of the visual sense area, but that jjrobably no part of the cor-
tex of the occipital lobe, and perhaps also of the posterior part
of the angular gyrus, is unconnected with macular representa-
tion. The cortical field lor the macula lutea woidd thus ex-
(^eed by far that ordinarily assume<l for the visual sense area.
The view of Wilbrand f in somi'what similar to, although by no
means identical with, that of von Monakow.
Henschen's J idea that the field for the macula corresponds
to the region of the anterior ))art oidy of the calcarine fissure
is negatived by cases in the bibliography, while the view of
Fdrster ami Sachs,* which assumes that the region correspond-
ing to the posterior i)art of the calcarine fissure is that in which
the macular representation exists, is negatived by the instances
cited by llenschen.
On reviewing the whole subject of hemianojisia it would
seem possible to do without such an elaborate scheme as that
* von .Monakow, (". Hxpcriinciitollo mid iiiitliolo^^iscli-iiiiiitoniischt'
I'litfrsiichungiMi iichcr ilii; optiscliun ('ciitrnn unil IJaliiicn nnl)st klinisclieii
heitriifjiMi zur cortipalcn Ilomiiuiopsie inul Alexin (Xoiu; Folge). Aroli. f.
I'syi'hiat. u. Norvcnkr.. I5.t1., ltd. xxiii (lHni-'03), S, OnO ; \\d. xxiv (18i)2),S.
2',>i").
t WilliriiiHl. II. Die Doppi'lvciso^iinf; diT Macida liilca. Festschrift,
fiir Professor Forstcr, WicsliadtMi. iHit.').
\. O/i. rit.
** Saclis, S. Das (icliirn dcs Forstor'scdioii Rindciiblitidcn. Arb. aiis
d. psychiut. Klinik in Broslau, 18!)."), S. .'>:5-104.
(HiOl'lMNC AND CllAININd TOdl^miKIf OF NKl'KONKS.
s:i7
suggested by voii Moiiukow or tliat suggested hy Wilbraiid.
While it is not iiupossihle tliiit tlie iiiiicular representation in
tlie lateral geniculate body is widespread,* as von Monakow
\nsual seiuii! area
I.esKjn
l.oliuA puritluli*
Cfirliral
cortex
Rndiulio occipilo-
Ihatuiniiu CniluUti
Corpus qeiiiriiliiluin
litterule
Retina ,^inislnT
F"l(i Ti'.W. — Silicinc of tlic I'fiitnil (iiitir |>;itlis, illiislnitiiii; Von MoiiMkuw's view dl"
tile n'ld'cscntutiiiii of (lill'crciit |m ill inns (if tlw i-ctiiiii in tlii'<'(irims;,'ctii('nliilniii
liUcnilc and his cxitliination nftlic I'iiil tli;il niiicnlar vision is unilislnrlii'd in
conical iicniiiinoitsiii. Al'lcrC. von MonaUow, ( icliirM|iiilliolof;i«'. Wicn. IS!I7,
S. loS, Fiji. 1151. 1 (I /) c, ^ani;lioii cells ol' rcliiia on riKliI side sending axoncs
to X.opt. ; (/i, hi, ('i. jianulioii cells in the lionionynions part of the left retina ;
I'. III. }i-r., macnlar neumnesof the rijiht side ; /•'. m. c. niacnlar neurones of the
left side : Ni, St. .V3. ^^, neuroiK's the axones of wliicli run tliroii^di tlw radialio
occipito-tlialaniiea (Iralioleti to the lolms occipitalis; a. fi. y. neurones with
interrupted axones at r. While most of the retina has limited re])resentation
in the cor|)Us f;<'"'«"latum lalerale, von Monakow helieves that the macula
lihres are distrihuted over the whole nucleus. Willi every crossed optic lilire
there terminates also an uiicr<issed optic lihre, a<e(U'iliiif; to his view.
suggests, yet it seems to me unnecessary to iissunie that the
fibres from the lateral genieuhite body hiive so wide a cortical
distribution as he would give them. Indeed, there is very
much anatomical evidence tigainst such a wide distri])utioii.
It seems to me much more likely that the matailiir field corre-
* lloiischen. in a recent article (Ueber Localisation iiuiorlmlh des aeiis-
seren Kiiiegaiiglioiis. Neurol. Cenlralbl.. beipz.. IJd. xvii (IHDH). S. 1!I4),
speaks for a restricted localization in the lateral f^enieiiiate body, and cites
a case in which the flndinfi;>< demonstrate that the dorsal portion of the
lateral geniculate body corri'spoiids lo the dorsal qiiailrant of the retina.
\
-I ,f
1 >
n
ii
"ir'
\m
828
TIIK NEI{ vol's SYSTHM.
spoiids to the wliolc length of tlic cortical area corrcspondiug
to the cali^ariiu' iissure, and that involvenicnt of the whole of
this area is necessary to cause (U feet of the visual Held corre-
sponding to the fixation point. This wouhl he in accoi'd not
only with the findings of Kenschen l)ut also with those of
Forster and Sachs, and, as far as 1 am aware, there are no ana-
tomical data thus far which contradict it.*
In the periphery of this visual sense area in the inirrower
sense there is (hmhtless a considerahle area of cortex which
receives fibres from the occipito-thalamic radiation. From the
visual sense area in the wider seiiso — that is, tlie region corre-
sponding to the distril)Ution of all of the fibres of the occijjito-
thalaniic radiation — there j)ass out (h)uhtless nniny axones to
neighboring gyri in the ])arietal and temporal lol)e, axones of
neurones associative in function whi(;h bring the a(!tivities of
the visual sense area into relation with the activities of other
centres in the cerebral cortex. Some reference to these associ-
ation neurones, which nuiy, in a sense, be looked upon as the
neurones of higher visual centres, will be made further on.
* III ii vory iiiipoHant cast! desorilicil by F('>rstfir (.\r('h. f. Oplith., HitI.,
Hd. xxxvi) 1111(1 s!.ii(licti aiialiJiuically by Sachs (.Vrbcitoii mis d. )isyfliiiit.
Kiiiiik iin Hrcslau (18!)5), 11. 2) the patient had had, in 1HH4, an attacii wiih
sudden loss of the right half of botii visual fields with the exception of
from one degree to two degrees near the fixation point. Five years later
heniianoiisia involving the left halves of the visual field set in. With this
double iieinianopsia, however, central vision was retained. Hearing and
writing were not at all disturlx'd, although it is true that the sharpness of
vision had diminished by one lialf, the power of distinguishing colors was
lost, and there was inability to recoi^nize the reciiu'ocal position of things in
space. Ill IH'Xi the individual <lied, ami at autopsy a doubled-sidcd h^simi,
involving the medial surface of both occipital lobes, was found. Tiie luain
was divided into serial sections, and it was discovered that ])riictically tiie
whole of the medial surface of both occipital lobes and the adjacent white
matter were destroyed, with the exception of a small portion of the peduncle
of tin? cuiieus lying anteriorly and the most jiostcrior part of the region of
the calcarine fissure which had escaped uninjured. This case, more than any
other in the bibliography, suggests that macular representation extends lie-
yond the medial surface of the occi]>ital lol)e. But it is not impossible that
the small area at the posterior extremity of the cidcarine Iissure sulliced fur
the central vision. At any rate, until a case has been studied in wliicii
there has been complete loss of the visual sense area in the region of both
calcarine tissures. with retention of central vision, we may hold on to the
view tiiat the macular ntpresentation corresponds to the region of the cal-
carine fissure in its whole length.
j,h«|
CJKOLl'lN(i AND CllAINlNli TUdKTllKlJ OF NKUitOXKS. s^y
HfmianopU visual fitlJ after ttnion ut y.
^ Fixation point
ftvtina tlextni
pursnasii/i'
N opticus tUrxlgr,
fasciculus crucialus
Keliiui sinistra, .
pttrs tempont/is
N.oplicus sinister, fasciculus non-crucialut '
fiisciculus macitittrts
^•(^_ k^tuiu itexrra,
purs temporalis
KiiiliuJio
occipitolAaJumi
Oratiolttl
Oyn occipitales
y. opticus ilc.\tcr, ftisciculus no/i-cnicialus
N. opticus dextir, fasciculus maeularis
l.obus tamporalus
til.-, tu/uctjlutu/n
Piilvinar
\uiiulw
. :p:t,^fll,ll.tnt!nt
Kisciciilus hnffitudiiialis
~ suptriar
•'lituUinotis
uifcrur
I Cyrus Ungualis
Tupetum
occipitalis
Fissuru cutcurina
TapctuiH
Cyrus hippocampi
Vnntrtcuius lateralis
(comu posttrws)
■
l'"l(i. 5IW. — Scheme iit" the cdurse iif the ni)tie jinths reiU'eseiiteU in ;i linri/niital
pliiiie. Willi illilstniliiin ulllie uceuriiiue of ciirticiil iiiiil >iil(icirtiiiil heiniiiii
iipsia. I After ('. Vnli MdllllkdW. (ieliillllKltlinln^jie. Wiell. IS'IT. S, till, i'ili.
I'^l.) Oil the iel't siih' the nptie (Kilhs !iic led : iiii the rii;lil >iih' l)l;i(k.
.1. hypothetical h'simi in tnictiis (iplicii> ; //. hypcithetical Usimi in white mat-
ter nl' (iccipital lolie. With hsidii at // there wiiiiiil he interrupt iciii not eiily
(pf tlie tihres III' tlie (i|)lic railiatioii. hut alsn ul' the axuiies cif thi' l'asiiculu>
hiiij;itmliiialis inlerinr. so thai aloiin wilii ri;;ht-siihMl liemiaiiopsia lliere
wonhl lie also alexia. //, iiodiile ill the while mailer near the lissura cai-
carina which coiihl cause liemi,iuii;i-i i without alexia.
m»t.
ijijiwi
I!
S3()
TIIH NKUVors SYSTHM.
In the diiigjrani (Kig. no;*), also tuki'ii From von Moniikow^
the principal h'sions which occur in liiiiiiiin hoinj^s in the do-
main of the optic paths arc well ilhistratc(h
With r.'<,Mrd to the centripetal tlbres carryinjjt the impulses
to the nucleus ncrvi oculo-niotorii and leading to reflex contrac-
tion of the pupil the following jjositive statements (?an he nuide :
In the first place, they arise from ail portions of the retina,
inasmuch as a ray of light thrown u])()n any given minute area
on the surface of the retina will lead to reflex contraction, pro-
vided the nerve tracts are in a normal condition.*
In the second place, these fibres run through the optic
nerve, the chiasm, and the tract, and undergo partial decussa-
tion in the (ihiasm. This is proved by tiic so-called " hemian-
opic {)upillary inaction " of Wernicke. Wernicke showed that
in hemianopsia due to a lesion of the optic tract illumiiuition
of the homonymous halves of the retina affected will not cause
contraction of the pnpil, while, on the other hand, illumination
of the op{)osite halves of the retina leads to pu])illary contrac-
tion, and the pupil contracts normally on convergence.
It is further known that the puj)illary path passes through
the hrachium (juadrigeniinum su])erius to reach the colliculus
superior of the corpora (|uadrigeniina and thence goes to the
nucleus nervi oculoniotorii in the floor of the af^ueductus
cerebri.
More than this, perhaps, can not be said with certainty, and
the most divergent views are held regarding certain details of
the path. Thus, for example, the total number of neurones
concerned in the passage from the retina to the nucleus nervi
oculomotorii is disputed. Whereas a certain number of inves-
tigators hold that the retinal axones pass directly to the region
of the oculomotor nucleus, others maintain the existence of
intermediary pupillary centres. Bogroff and Flechsigf have
described a root of the optic tract which passes directly into
the stratum griseum centrale of the third ventricle. The evi-
* III this connection the following urticles should he, consulted : (1) Pe-
retti. Kin I"'!!!! von Atrophia Nervi optici (h'scciidens nach Scliiiih'l VcrU't-
zung. Deutsche med. Weluisohr., Leipz. u. Berl.. Md. xix (IW);!). S. ;J01.
(2) Sachs, Z. Kinschniirunf:: lUn- Seimerven durch jresaiTunte (n-fiisse der
Ilirnbasis. Arch. f. Aii'.'enh.. W'iesli.. Hil. xxvi (lS!)L>-"!t;5). S. 2;i7-274.
+ BofjrofT and Flechsig. Neurol. Oentraibl., jjeipz., M. v (1886), S. 551.
Cited by von Hechterew.
j:!
(JUoriMNMi AND ClIAININd TOdKTIIKH OF NKrKOXKS. s'M
(lotiou at present is in favor of an internietliary nueleus in tlio
pupillary path, i)iit just wiieri' that nueleus is situateil is still a
matter of douht.
Darkschewitseh * believes tliat the pupillary fibres leave the
traetus opticus in the rejjfion of the corpus jfeniculatuni laterale,
and {)ass through the thalamus to the corpus pineale and the
ganglion habenulie. Heiu;e the reflexes are mediated i)y means
of fibres which pass through the posterior commissure to .his
ohcrc Ornliinioforiuxki'rn. His conclusions were arrived ut
after study of degenerations following physiological experi-
ments, and they iiave received sujjport from Hellonci f ou the
ground of his studies in comparative anatomy.
The views of Darkschewitseh have received a partial con-
firmation from the studies of Mendel, who supports the doctrine
that the ganglion habenuhe is a jjupillary nucleus. Mendel
extirpated the iris in new-born animals, and asserts that he
found atrophy of the ganglion habenuhe of the same side, and
of certain fibres of the posterior commissure. According to
Ids view, therefore, the reflex path for the iris would be through
the optic nerve, chiasm, and o])tic tract to the ganglion habeu-
uhe of the same side, thence by way of the commissura posterior
to von Gndden's nucleus, and to the nucleus nervi ocudomotorii.
A somewhat different idea is advocated by von liechterew.
He follows the pupillary fibres through the optic nerve of the
chiasnui opticum, but states that they do not cuter the traetus
opticus nor the geniculate bodies, but close behind the (diiasm
and without decussation enter the stratum griseum centrale of
the third ventricle, whence they pass uncrossed to the nucleus
nervi oculomotorii.J He bases his view \\\w\\ tiie following
findings: (1) Section of the optic tract in the dog caused
hemianopsia but no alteration in the pupil ; {'I) destruction of
the superior colliculus, or of the corpora geniculata, did not
abolish the reaction of the pupil to light.
* Darkschewitseh, Tj. Uobor 'lie soponanntcn priiniiroii Opticiiseciitren
unil Hire Hczicliuiig /.ur Orosshinu'inde. Airli. I'. Anal. ii. I'hysidl., Aiiut.
Abtli.. beipz. (1880). S. 24!)-270.
t Holloiiei. (}. Ztsclir. f. wisscnsdi. /,(mi1., IM. Ixxiv. II. 1. S. 25.
X von Heclitorew. \V. I'cber den Vcrlauf dor die I'lipiile verengenden
Xervenfaserii ini (tohiru urid uebor die Localisation eiiies ('entrimis fiir die
Iris iind Contraction dcs Augeiiinnskeln. Arch. f. d. ges. Physiol., Bonn,
I?d. xxxi (18H;{). S. CO-HT.
I P''
8)52
TIIK XKIIVOUS SYSTKM.
te-:r
U '.;
I ■
IIiMischcii * ciiipliiMizoa tlie fact that Wornickc's obnorvation
of liemiuiiopic piipilhirv inaction in lesions of the optie tract is
(hx-isivc in fnvor of tiie view that the pupillary fihres run in
the tractus opticus. They jro at least as far as the border of
the peduneulus cerebri. The case reported by Leyden f is
esjiecially valuable in this connection, as is also a case reported
by DercuTii, of Philadelphia, llenschen states that a series of
cases sui)ports the view that the jjupillary libres do not enter
the lateral ".geniculate body, and holds that Knies is probably
wrong in thinking that lesion of the lateral geniculate body
can give rise to Wernicke's hemiaiu)pic pupillary sign.
Although the evidence is not yet conclusive, it seems to
me most probable that the pupillary fibres run through the
brachiuni (piadrigeniinum superius into the superior coUiculus,
there to come into contact with the cell bodies and dendrites
of neurones in the nucleus colliculi supcrioris, and thence the
impulses pass by way of the axones of tlie latter to the nucleus
uervi oculonu)torii of the sanu; and of the opposite side. At
any rate, the histological investigations of Ilekl make such a
view plausible.
The statement is frccpiently made that the coarse fibres of
the optic lu'rve are those which are concerned in pupillary
reflexes. J3ut even this is not definitely proved. J
The conducti(m paths in connection with the eyes should
not be dismissed without reference to the centrifugal fibres of
the optic lu'rve discovered by Ramon y Cajal. The existeiuse
of these fibres has been confirmed by van (iehuchten, voji Kolli-
ker. Held, and others. The cells of origin of these centrifugal
axones are situated in the centres in the mesencephaloJi and
diencephalon. They have not only been demonstrated by
(iolgi's method, but their existence and disposition has been
ju'oved also by the methods of secondary degeneration. Ac-
* Ilensehen. S. E. Ueber hcinianopiseho I'lipillonronktion. Klinische
uiid anatDinisL'he Beitrilgc zur Pathologic ilcs (loliirns. Driller Theil. I
lliiifte, ri)sala (1H!)4). S. lOi).
t lit'yiU'ii, K. Hcilriigc zur topisclieii Diagnostik der Gehiriikrankhoiton.
Internat. Beitr. z. wissensch. Med., Festselir. K. Virchow . . ., Burl., lid. iii
<1891). s. 2H;i-;5or).
t The visual and pu|tillary paths have recently been reviewed by K. Baas.
Die Seh.- uiid Pupillcn-Bahiuii. Breslau (18!)8). The article has not thus
far been aeeessible to nie.
I fit
<iH()ri'lN'(i AMI ClIAININd TiKi KI'llKli <»1' NHlUoNKS. s;{;{
conlinf? to the fuuliiif^s of voii Moiiiikow, following,' scctiuii of
tilt' optic ti'Jict tlit'i'c is (U';j;('ii('riitioii of cells not only in tlw
sii|K'rior colliculiis of the corpora (|Ma(lrij;»'iniiiii, l)ut also in the
lateral geniculate body (dorsal (;au(lal part, wliicli lie designates
us ii) and the j)ulvinar. The termination of these tihres in the
retina appears to he in the internal inoleciiiar layer, foi' the
G.c*
3c.R
N.trocKliari*.
Tempo'jl part.an
Fid. i^IW. — Sclicinc of visual cniKliictioti patli. Lcttcriiif; siinic as t'ln- Plati' 11,
I'iK. 1.
terminals probably eomo into contact with the amacriiie cells,
which Ramon y C'ajal has described in tliis layer. I'ossilily
they act also iijx)!! the liipolar cells (peripheral optic sensory
neurones) themselves. .Just what the nature of these centrifu-
gal impulses can be is hard to imagine. Several theories have
been suggested, but none of them is satisfactory, and they need
not be discussed here. It nuiy be that the retina is brought
KU
Till-; NKltVors SVSTKM.
under the inllnciicc of the ccn-ltnil cortex tlirou^li these eeii-
lririi»j:iil neurones, since tin' liirjie pvriiinidiil cells in the tliiril
cortical liiyer, the so-called solitiirv cells of the visual sense
ari'a, send their axones down Ihrou^di the optic radiation and
throiijjh the posterior limit (tf the inlenuil capsule to the optic
eeiitren in the diencephalon and nu'sciicephalon. '{'hese cells
de^enerati- after lesion of tlii' internal capsule or (d" the occipito-
t'lti. .list. Scliciiic III' visual ('((lulucliip!! jiiitlis; the iitU'i'inK is tiir simc as Inr
I'lali' I.
tliulaniic radiation. It seems prohahle that the majority of
these axones run to come into conduction relation with the
mesencephalic orpin coMtrollinjjj the eye muscle nuclei, but it
is not impossible that some of them terminate about the cell
bodies and dendrites of the neurones, the axones of which form
the centrifujjal fibres of the optic tract and optic nerve.
In connection with the visual conduction paths it would
have been interestinj; to discuss the various theories of vision
whi(di have been put forward, especially those proi)ounded by
(■ lis I'lir
ity of
h the
l)ut it
U' vvW
1 form
woiiUl
virion
UH
I by
(iU(>UIMN(i AND rilAININ(J T()(iKTIIi:it ol' NKl'IfONKS. Sll")
■llliiiiil '
CvMy'k
{LhuuU.
P..
IlchiilioUz,* Ilcrint,', t (Ji'MtT, ]; Doiidcrs,'* von Krii's, || mid Mi-m.
Kraiikliii,' l)iit they caii only lie mciitioiit'tl luTi!, iicidiiipiiMii'd
by the biblio<^ni])hic rid'crt'iiccs.
In I s. r);{;J iiiid ma the inorc important and best known
ccntripcl.ii nt'Ui'oncs of tbo visual conduction path arc schcmal-
ically rc|)ri*senttHl.
♦ Ib'lmlinliz, II. TcImt (lie 'I'licorir (Icr ziisiuiiiiicnp'si't/teii l''iirl>fii.
Svo, IScrliii, l^^t'2. — lliindliiicli (itr jiliysiologiscilieii Optik., II. Aiill., Iji'lp/.
(1^<SH).
t llcriii-;. K. I.clin! voiii Liclilxiiin. II. Anil., Wioii (IHTH).
I (liillci-, A. Die Aiuilysc diT biclit wcllcii iliii'di das Aiij^c. I'liii Mcitnif;
zur Krklilrun;,' licr KnrlM'iicmpliinluiif,'. Arcli. I'. Aimt. u. I'hjsiol., iMijsinl.
Abth. (1WW8). S. i;«)-Hi2.
* Duiiilt'is, I''. ('. Nocli cimmil die Fiirbt'iisysU'inc .\\vh. f. f)plilhiiliM.,
M. XXX. Al.th. 1 (IHHl).
J vdii Krics, .1. I'lntfjcjjmmi,' an llctrii V.. Ilcriiij;. Arch. f. d. ges.
I'liysiul., MiPiiii, i?d. xli (IHHT). S. :!S!l-:!!»T.— 1'c1>.t die FarbciildiiKllicil dcr
>ifl/.liuut|p('ri|p|uTif. /tsclir. f. I'syclidl. u. I'liysiul. d. Siiiiiesorg., llHiid). ii.
Loipz.. lid. XV (18!)T). S. 'J47-2H!).
^ Franklin, Ciiristiiii' baild. Fine nciic Tln-oric dci- biililiMiipfindini^'i'ii.
Ztschr. f. Fsychol. u. Physiol, d. Si^n(■sllr^^. Ilanil). u. bcip/.. I5d. iv (IS'.rj).
— On 'riii'iirics of Liglit Sensation. Mind. bond, and IvlinI).. n. s.. vol. ii
(lH!i;{), J))). 47n-4H!). — .V New Thi'ory of bi^lit Sensation, .lolms Mop-
kins I'niv. ('in:., Unit., vol. xii (Ih0;i). |ip. KtS- 1 lo.— I'rorcssor Fl>l>inj;liaMs'
Tlu'ory of C'(dor Vision. Mind, bond, and Kdinl)., n. s., vol. iii (1H!M), p.
1(>:{.— Professor MiUlcr's Theory of the biijhl Sense. Psychol. I!ev., N. V.
and bond., vol. vi (1H!)!(), pp. Td-f^o. — Mrs. l''raidilin's oltservations upon
"normal faint-liglit foveiil blindness" are rtM'orded in i'sychol. Kev.. N. Y.
and iiond., vol. ii (IS!).")), pp. 1:17-148.
(
mm. .
ii
^i.
mi].
I
•
H- 1
iiii
("HAITKU LIV.
AllMTOKY NKIUONKH OK TIIK SKCOM) AM) Ol" IlKHIKll
OKI) Kits.
Nuclei tcriniimli's of N. coclilfa' — (ii'iiiTiil view of (■ciitral autlilory piiUis —
Striii' nicdiilliiri's — Corpus trapc/oidfiiiii — Superior olivary <'oiii[)lt'x —
I-fiiiiiisciis lateralis — Nucleus leiuuisci lateralis — Colliculus inferior —
<'i>rpus p'liieulMtuni nieiliale.
Nucleus iiervi cochlea' ventnilis — Nucleus uervi coclilea' ilorsalis — Nuch'us
olivaris suiierior — Nucleus corporis Irape/.oidei — Nucleus pra'ojivaris —
Nucleus semilunaris — Corpus trape/.oideuin — lieiiiniscus lateralis — Nu-
clei U'innisci lateralis — liolatioiis of tlie lemniscus lateralis t(» the nucleus
colliculi inferioris, the corpus p'liiculatuui mcdiale. and the pallium —
Acoustic rellex |iatl)s — Aiulitory sense urea in the cerehral cortex —
Schemes of auditory [lath.
4. Central Neurones of the Auditory Conduction Paths.
Tin: pc'rij)lu'riil iuiditory nourones couiu'ctiiifj tlio ori^Mii of
Corti with the rhombeiiccphaU)!! have hccii (li!scril)e<l in an
carlitT chapter. Wt; havo seen that the cell bodies of the ])e-
ri})lieral auditory neurones are situated in the ^an<;lion s])irale,
tliat their deiulrites are distributed to tiie ()r<riinon spirah'
(Cortii), and tlmt their axones pass throufrh the radix coehlearis
of the nervus ucustieus to terminate eliieHy in the nuideus
nervi eoehh'aris ventralis and tlu' ntich'us tu'rvi eochleiiris dor-
salis (tubereuluin aeusticuni), a portion of the libri's, liowever
(aocordini^ to llehi), f^oing farther, to terminate first in the
nuck'us olivaris superior of the same or of the opposite side, or
in musses of gray matter situated even higher up in Jie centnil
tu'rvous system.
Witii regard to tlie central auditory paths, the results of
dilTerent investigators in earlier yi-ars were markedly discord-
ant. Thus, while Forel, Onufrowicz, and von Monakow denied
that the fibres of the tra])ez(tid body had anything to do with
the central auditory path, i-Mechsig, von Hcchterew, Miiginsky,
Bumni,and others maintained the opposite view. Neurologists
836
If
I
(JUOll'INd AND CIlAININd ToOHTIlKK <>1" NKl' UoNKS. «;{;
an- to 1m' i(>iiirni(iilatc(l that tlirnii;,'li tlif rcscarclics nf tin- past
few years, hy iiicaiis of a variety of iiietlKMis, we have tiually ar-
rived to imi(;Ii more Melinite aiitl satisfactory iileas repinliii;;
this portion of the nervous system. 'I'lie views to lie oiitlincil
here, whieli may l)e eotisiijeretl to represent tlie presen' status
of our knowled/^e regarding' the auditory conduction iiisith> the
central nervous system, are hased upon ri'searches of Kh-elisi^j,*
von Monakow, f Held,! von Koiliker,* Ramon y ('ajal,|| aiul
Fh»reiu'e Sahin."
In i^'cneral, it may he said tiuit from the nuch-i termitudes
of the cochlear iM-rvc, axoncs of neurones (d" tlie second order
]mHS by way of botli tiie striiv medulhireH and the corpus trape-
/oideiim to tho ref(ion of tlio superior olivary complex of both
sides, principally of the oj)posite side. Many of the til»res ter-
minate in the nucleus oli\aris superior ami in the j;ray nuclei
of the c(»rpus trajjezoideum. Others of them ^'o on (accompa-
nie(i by axones arisinj; in tiie luudei in winch their fi'Uows stop)
to pass through the lemiuscus lateralis to the coUiculus inferior
of tlu' corj)ora «|uadrif^emina (FifJ. MI't). On their way a num-
* I-'lcclisif,'. I'. Zur I.clirc vum cciitrult'ii N't'rliiiif dtT Siiiiicsm'rvrii.
Nciircl. (Vntrall.l., I-cipz., lid. v (|HS(i). S. ilT-100; also Wcitcrc Mitthcilun-
P'li iicliiT (lie ISc/icliuiificii (Ics iiiitcrcii V'ifrliligcls ziiin lli'irncrvfii. Ncurtil.
(Viitrallil., Lt'ip/.., Hd. ix (1H!)(),, !)^i-i()0.— Die Leculisaiion der gcistijfcn
Vorpingc, iiisl)('sotitlt'rc dcr SiniicserapfuidutiK<>M dcs Meiisclu'ii. Leipzig,
ISiH).
f voii ,>[()iiakow, ('. Ueber eiiiigc dunli Kxstirpation circumscriptcr
Hirnriiideiin'gioiicii bcditigtc Kntwickcliiiigsliciniiiiiiip'n dcs Kaiiiiiclicii-
gchinis. Arcli. f. i'sycliiat. ii. N'crvcnkr.. Hcrl.. Hd. xii (1NH2). S. 141 ; .W.l.
— Nt'uc oxpt'riiiiontollc ncitriijic zur .Viiatoniic dt-r Schlrifc. N'ciinil.
(Vntrall)l.. Leipz., Hd. iv (IHsr)). S. '.'0r)-2()K.— <'<.r. Kl. f. Schwciz. Acrzt..
1887, Ni). 5. — Striao Acuslicac imd uiilcrc Sclili-iff. Arch. f. I'svcliiat. ii.
NiTvenkr., Merl.. Hd. xxii (185)0). S. l-2(i.
t Held, II. Die ('('iilnilni Haliiii'ii ilcs Ncrviis aciisticiis tici dcr Katze.
Art'h.f. Aiiat.u. Physiol.. .\nat. A lit h. . Lcipz. (18<»1), S. -'71 -•,'!»!. — Die cciii rale
(Jehorleittnig. Arch. f. Aiiat. ii. I'hysiol.. Aiiat. Atith., Leipz. (lH!i3). S.
2(11 -IMS.
« voii Kr.lliker. Op. rit.. S. 258 IT.
II Kanion y Cajal, S. (»ri<;iiies del aciistier) en lets aves. Alj;iirin> eoii-
trihiieionos a! Cdiiocimieiitd de los ganglids del eiieefaln. Madrid, l>>i!t4. —
Nervio cochlear y ganglios acuslicus. Apiintes para el esiiidindel liulbo
rnqiiitico. ccrehelo y origen de los iiervios encefalicos. Madrid, 1^95.
■'' Sabiii. Florence. On the .Anatomical Uelations of lln' N'lielei of Re-
ce[ition of the Cochlear and \'estil)nlar Nerves, .lolins Hopkins llosp.
Hull.. Malt., vol. viii (1807), pj). 2r);{-259.
;*^ffl»^i:
if^
S38
TIIK NKltVors SYSTEM.
fn
!
\\r i ,
Ife
1
her of tlicni tcriiiiiuitc in iill |n'()l)iil)ilit y in tiic nucleus Iciiiuisci
liitt'i'iilis.
'IMu' colliculus i?it'eri()i' must he looked upon us one of the
most iniportiiiit way-stations in llie central auditory ]»ath. In
the nucleus collieuli int'erioris terminate, i)erliai)s, the luajority
of the fibres of the lemniscus lateralis; a (iertain numher, how-
ever, go farther forward. These fibres pass on maiidy through
f
Ciilliciihi.i inlVriitr.
Rail i. I- ilt'M'i'iiilriis )llisvtirriili<lli<<l
•V. triijciiiiiii.
h'dsciriilKs loiiiiiliiilhiiilis iiiidiiilis
l.i'iiiinsrii.s lull' nil i.t.
Triicl fnnii tlif riilliriilim ti)iii>riiir
III til)' vi'iitriihitirdl finiiiiili
(;V« t ':/ ~ 'Z, - — -. ' KL-lk/ \ format to retivnltnis.
i ( J - N/ » ' ■ .^ . / ' '\'l:ltlil \
^1 I I ■y/ ^^ * , -'{/ \^WW"~^ \ l^"'i'ff'' f>'<"ii iiiK'li'1'1 rtiliir It
'&.'<"/' \<'i'i'n.i tn'i/'iiiiiiii.i.
;rJ.
('iiijiii.i tid/D'ZDiili'inii,
Vh,. .");{.'). — ()l)li(|iit' si'ctiiiii tliniuf;li the Imiiu siciii «[' a iicwIiDni rut, illustraliiit;
ill III!' si'|i:trati(>ii. in tlic su|ii rior |>iii't nt' the jioiis. nt' the iMsciculiis loii^^i-
liidiiuilis iiicilialis rnmi llu' lilirc system (Icsci'iidiiiK fniiii Ilic culliciiliis
siiix'riiir to tlic vciih'ii-latcnil runiciili ; iiiiil (;.') the relalioii <it' the laleiMl
leiimiselis to the colliiiihis iiit'erinf. After II. Ilehl, Ahhaiidl, il, iiiMtli.
[ihvs. CI. (I. k. siiehs. (iesellseh. il. Wisseiiseh., Leip/.., 15(1. xviii, Nci. ti, Is'lri,
TiiV. ii, FiK. !1.)
the hrachium inuidrigominuni inferius to reach the corpus
geiiieulatiim niediale, where apparently a large number of them
terminate in the nucleus corporis genituilati mcdialis. In the
latter nucleus are situated t\w cell bodies of lunirones, tln^
a.xones of whicdi pass forward through the retrolentiforui ])or-
tion of the (uipsuhi interna to reach, by way of the corona I'adiata,
Wp^'f
(}|{(>IMMN(I AN!) CllAIMNti 'l'(MiKTIIKI{ ()K NKriJONKS. s.".',*
the iiiidilorv sciisi- ari'ii in the ccri'l)!-;!! cortex (jiiiu'tion of
thinl and fourth lifths of jjyrus t('in])orali.s siiju'rior, toi^ctlicr
witli the jiyri tcniporah's traiisvcrsi). It is ])o.ssihU' tiiat some
librcs from tiic hitcral lejiuiiscus ij;o ])ast the <f('iH('iihiti' Ixxly
without stopping to tcniiinati! first iu tiio auditory sense area
in the (-(^reljral cortex (so called direct acoustic (!ortical path
of Held).
The smallest number of neuroiu'S superimposed to form the
auditory conduction path from the internal ear to the cerebral
cortex is therefore, in all probability, three — one extend in<,'
from the orjjjan of Corti to the nuclei termiiudes of the cochlear
lu'rve (peripheral auditory neuroiu' or auditory neurone of the
first order) ; a second })assing from the nuclei terminales of the
auJitory n''rve to the cor])ns geniculatum mediale (rhomben-
cephalo-dieneephulio auditory neurone or auditory neurone of
the second order) ; a third extending from the medial geuiculatt!
body to the temporal lobe of the cerebral cortex (diencephalo-
teleiicephalic auditory neurone or auditory neurone of the third
order). While sutdi a superinn»osition of neurones is to be
regarded as the simplest and most direct arrangement i)ossibIe
in the auditory conduction path, it seems likely that there are
other nu>re complicated aiul ])erhaps far less direct (lombina-
tions of neurones which make up the i4)])aratus of the conduc-
tion of auditory impulses.
Thus it may even be that the simplest auditory (M)nductioii
path ctmsists of at least four superimposed neurones, r)ne extend-
ing from the organ of Corti to the nuclei termiiudes of the coch-
lear nerve (peripheral auditory neurone or auditory neuroiu' of
the first order) ; a .secoiul passing from the nuclei terminales of
the auditory nerve to the coUiculus inferior of the corpora (|ua-
drigemimi (rhomben<'e])halo-meseiu'ephalic auditory neurone or
auditory neurone of the second order) ; a third extending from
the colliculus inferior to the corpus geniculatum mediale
(mesencephalo-diencephalic auditory neurone, or auditory neu-
rone of the third order) ; a fourth extending from the medial
geniculate body to tlu' auditory seii.se area in the cortex (dieii-
cephalo-telencephalic auditory neurone, or auditory neurone of
the fourth order). P'urther, a whole series of nuclei interca-
lated in this conduction path have to be considered : the nuclei
terminales of the cochlear nerve, the nucleus olivaris superior,
the nucleus corporis trapezoidei, the nucleus pra'olivaris, the
1
840
TIIK NKKVOlS SYSTKM,
S
iiinleus semilniiivriti, tlie micleus Icmnisoi latoralis, the nucleus
colliculi inferioris, ;inil in iulditiou the mu'lcus corporis genic-
uliiti me(!!iilis, iiiid po.ssibly other uuisscs of jiTuy matter in
tlie liypotliMliinms not yet clearly defined.
It is not impossible tliat, Ix'sides neurones extending l)e-
tween ihcsc ditTi'ri'nt j^ray inasses and connectiuf; them witli
one aiiotlier, (ioliri cells of Type II, or dendnixones situated in-
side tile individual .irray masses, may phiy a part in tlie conduc-
tion of auditory inii)iilses.
No attem[>t will he Jiiade to •/\\c Ik re an exluuistive de-
scription of all the nenroiu's which are jirohahly concerned
directly or indirectly in the auditory conduction path. In tlie
first place, our knowledjje of these neurones is by far too frag-
mentary to pt-rmit of an exhaustive descri])tion, and in the
second place, for practical jmrposes, it would seem to be much
more important that tlie stndent possess a clearly defined idea
of one or two of the princi})al 2):itlis than that he have his con-
ception confused by a mass of bewildering details which can not
us yet be adecjuately valued.
Since their discovery by Piccolomini the sfn'<p mcdtilhtrvK^
those Avhite bands which run across the floor of the fourtli
ventricle and which vary so enormonsly in dilferent individuals,
have attracted the attention of nmny neurologists (cf. Fig. 37^,
])p. 55T). Sometimes they may he entirely absent on one or
both sides; in other instances they are very markedly developed,
forming a very striking anatomical feature. The bands do not
run, as a rule, exactly transversely, nor are they all parallel to
one another, for one band may even cross some of the others.
One stripe, often seen running oblicjuely forward and to the
side, is known as the condnctor sonorns {Khuifisftih of Berg-
mann).* Later studies make it seem likely that liergmanirs
stripe really has nothing to do with the conduction of auditory
impulses. Embryological studies of von Bechterew show that
the striie medul lares become medullated at a relatively late
period. lie thinks that they have nothing to do with the
acoustic path, but represent cerebellar connections.
The study of secondary degenerations has thrown consider-
able light upon the peri})hcral and central relations of the stria?
* Bi'rijmiinii.fi. H. Xoiio I'atersuchungeii uober dicitiiiciv OriijanisiitioTi
tics (iehirns, llauuover (1^31), Hvo.
striie
lisation
(ilJoriMXli AM) (lIAIXINd TodKTlIKU OF NKlKoXKS. s+l
meduUtiros. Section of the cochk'ar norvi' causes hut little de-
feneration in the striie [Forel,* and Onufrowicz fj- Tiiat cer-
tain of the fit)res of the cochlear nerve enter directly into thestriic
nieduUares was sliown to l)e prol)al)le hy tlie studies of l>aginsl<y
and of Held, and has recently been prove*! definitely by Marchi's
method l)y Thomas. J The experiments of von Monakow proved
dire(!tly that the lateral lemniscus is in jtart u continuation of
the striic medullares,** and the later studies of the same investi-
irator II iiave nnide tlie relations of the striiv still clearer. Thus
section of tlit; lateral lemniscus in a newborn cat leads to
atrophy of the stria' acustica-, and of the nucleus nei'vi coch-
i' aris dorsalis of tlie opposite side. It is especially tlic cells of
the middle layer of tlie nucleus nervi cochlearis dorsalis which
atrophy on section of the lemniscus lateralis. The libres can
be followed from the dorsal cochlear nucleus around the corpus
resti forme on to the Hoor of the ventricle, whence they plunge
down ventrally to pass between the stratum griseuin centrale
and the nucleus nervi vestibuli lateralis of Deiters to reach
the raphe, where they decussate with similar fibres of the ojjpo-
site side, and pass to the dorsal wliite matter of the nucleus
olivaris superior on that side. Thence they turn upward into
the lateral lemniscus. It seems not unlikely that in the stria'
nieduUares are contained fibres which run in both directions;
namely, (1) fibres which represent axones of cells situated in
the nucleus nervi cochlearis dorsalis, and which pass upward
to the lateral lemniscus of the opposite side; and (2) fibres
which represent axones arising in the gray matter of the collicu-
lus inferior, and run downward to end in the dorsal cochlear
nucleus. Von Kolliker, who has carefully studied the striiB
meduUares, reserves the term stria^ acusticse for the fibres
which represent central connections of the cochlear nerve, and
* Fori'l, A. Vorliiufigc Mitlhoilunjjf ueber don Urs|iriiiig dos Nitvus
iicusticus. Neurol. Coiitralhl.. Lcijiz., TM. iii (1885), S. 101-10;j.
f Onuf'owic/, 1$. Kxporiiiiontcller Hoitrag /iir Ki'iuitniss ilcs Frspriuigs
(les Nervus aciistieus dos Kanineiiens. Arcli. f. Psychiat., Ik'i'l.. IM. xvi
(1885), S. 711-742.
\ Tlioinas, A. IjCs termlnaisons ceiitrak's dc la raciiif laliyriiitliiciuo.
Compt. rend Soc. do biol., Par., 10. s., t. v. (1898), p. 18:5.
* von Monakow, ('. Schwciz. natiirf. \'crsaintnl. in Genf (1880). and
Arch. d. se. phys. ot nat., (ionovo. 188(i.
II von Monakow, C Stria' Aoustica" iind luitoio Schlcifo. Arch. l".
Psvfliiat., Tiorl.. Hd. xxii (18flO). S. l-',Hi.
ii^.i
S42
TlIM NHRVor.S SYSTHM.
tlie term striiv modulhuTs for tlic fibres not eonoerncd in the
jiuditory path. He pictures a hir<;^e hnndle rumiiiij^ iurross the
floor of the ventriele in the middle line, then running ventral-
ward in the raphe to become external arcuate libres which go
toward the cerebellum (Fig. H'M')). It is by no means (X'rtain,
m
arc r
l"l(i. .");5t(. — Triiiisvcrse section of tlic limiiaii iiU'diilla oliloiiKata, NVcificrt staiii-
iiiK. (After A. von Kiilliker, llandbncli der (iewebelelire, \'I. Aiill., Hd. ii,
I-eipz., |M!((). S. :5H4, Fis. .').■)(). I ^'r, nucleus \. coclilearis vi'Utralis; .NV, N.
coclilea' : A7, nucleus funiculi teretis; A', continuation of stria' niedullares
dextra' et sinistra' tlirouKli tlie raphe and ilecnssation of the siine at the
hottoni of the ventral sulcus; the (ihres then ko over into lihne arcuatu' ven-
tniles ( Finrr) lateral from the pyramid and olives as far as the corpus resti-
forme (/'d.
however, that the latter fibres have anything to do with the
auditory conduction paths. It seems tolerably certain that the
stria? niedullares in man are quite different from those of many
animals, for in man there seem to be many more fibres which
hiive to do with the cerel)ellum than in the cat iind rabbit, in
which the stria> niedullares seem to be almost extdusively
auditory fibres.
The striie acustic* have been carefully studied by (iolgi's
method by Held and by Ramon y Cajal, and the results at
which these observers Inive arrived will be mentioned as soon
(IHoriMNd AND CIIAIXIXd T()(}KTIIKlt OF XIOrHONKS. s4;',
iis pjissiiiff notice has been fjiven to some of tlie otlier buiullcs of
ttbri's iiiul ffray iiiiisscs in connection with the iiuditory con-
duction path.
'I'hc hroad bundle of transvei-so fibres lyin.uf in the ventral
portion of the te<,Mnental part of the pons lu-ar its junction with
the niedulhi and dorsal to the fasciculi pyrainiihdes is known as
the rorpns fntprzoidvinii (Fi<is. 5:57 and (VJM). In tlu' interspaces
between the transverse fil)res are seen in transverse section
nuiny lu'rve fibres runninjf lon<,ntudiiutlly ; these re])resent in
tlie main the continuation upward of the stratum interoUvare
lemnisci to form the lemniscus medialis of the general sensory
path.
.lust dorsal to the corpus trapezoideum, sojnewhat laterally
placed, is situated the nitiiriis olinin's siipfn'or on each side.
In the trapezoid body itself is to be found the Hurlens rorjmris
frapczoidoi. Near by are situated tlu* midi'iis prfPoliran's and
the iiKclcus xciiii/iniiirix. The mixture of white and fjray matter
in the re<iion of the nucleus olivaris superior is often referred
to as the " suprrior o/inn-i/ roinp/c.c.''''
As to the nature of the corpus trapezoideum there has been
j)erhaps as much dispute us in the case of the striiv? medul lares.
Nevertheless, there can no longer be any doubt that the fibres
of the corpus trapezoideum in the main represent nu'duUated
axones of auditory neurones of the secoiul order, the cell I)odies
of the iKuirones being situated chiefiy in the ventral cochlear
nuclei of the two sides. The proof was first brought by Flech-
sig and von Hechterew, whoadduced the results of embryological
investigation (study of niyelinization), and their jmsition has
been confirmed by nu'ans of (iolgi's method by Held, von IviUliker,
and Ramon y ("ajal (rii/c ////Vv/), and by means of reconstruction
nu'thods (F. Sabin).
dust above the superior olivary complex begins the A'/»///.svv/.s'
hi/cndis* This bundle passes ui)ward toward the mesenceph-
alon, dorsal and at first somewhat lateral from the lemniscus
medialis. The majority of its fibres having reached the col-
liculus inferior of the cor])ora (|uadrigemina, terminate tlu're,
although many go on still farther through thebrachiuni (jiiadri-
geminum inferius to reach the region of the corpus geriiculatum
luediale. In sections of the brain of the newborn babe, taken
* I'liti'i-f Sfhicifo of the (iprmiuis, rulntn dc Ri'il iiifi'rii'iirof the French.
% 1 1
IP
I ■
S-t4
Till-: NMU VOL'S SYSTEM.
t >. "= := J. .i .' • - i r •,
^ "t ^ ;.^ ^- : 1 -^ = - .2 E
i. I.I? ti r i~ r""!
GROl'IMXa AND CIIAININC. TOOKTIIKIJ OF NHriJuNKS. s4r>
Fjsc.reNf.
Kid
i 1i
II
I !
:
■
III* i' y
m ■ ' ;
S4»5
Tlll<; NKIfVors SYSTKM.
tniiisvcrscly tliroiiifli the culliciiliis iiil'ci-ior, tlic fibres of tlic
liUcTiil loiiinis(ii.s ciiii 1)0 seen surroiiiMliiig the ventral surl'uce.
Nu.
Il.inf.
Fk;. 5:i!(. — 'rraiisv<Tst' section tlinm;;li ln-jiin of ncwlioni liiilic. Lcvi'l of rolliculi
infcriorcs of cniiponi (|ii;ulrif;<'iiiiiiii. i Wci^crt-I'iil. scries ii, section No. i!it(). i
Aq.irr.. miiicductus cerebri ; a, tilires rnnninj; from liiteriii leninisens towiiid
(iorsui Itovder of Imicliinni conjiiiiclivmn : II r. Cuiij., Ih'mcIi in ni conjunct ivnni ;
C.c.i.. eomniissure between tlic collicnli infcriorcs; /^cc./icc/*., vcntriil [(orlion
of l>raeliiuin con.jnnctivnni, wliicli in reality fonns a eomniissure between tlu'
suiH'rior inulei of the vcslilmlar nervesof llu' t wosides ; F.I. in., fasciculus lon-
{.'itndinalis medialis ; F.I'//., fasciculi loiiKitudinales pontis i iiyrauiidalesi : /,./.,
lemniscus lateralis in lar^e part lerminaliuK in Die nucleus of the collieiilus
inferior; /,.(».. lemniseus medialis; ,V./ I'.. N. trochlearis ; .V».r(///.(»/'.. nucleus
colliculi inferioris; ,V".r..s.i/ 1. nucleus centralis superior, pars lateralis;
.\>i.<\.t.' Ill ). nucleus centralis superior, pars medialis ; H.il.ii. I'., radix desceiidens
[mesenccphalica] N. trif;cmini ; Sl.fir c. stratum jti'i!^<'i'u centralc. i I'repara-
.ion b.v Dr. .F(din Ilewetson. i
of the mu'leiis coilieiili iiil'i'rioris very rmicli like a ciily.x (Fiji.
"^''e niirlciis lemin'sn lateralis is anatomiciilly continuous
with che nucleus olivaris suju'rior. altl)ou<.,'h tlic character of
the cells situiited in the foruuT is very (lifTcrcnt from thtit of
the cells in the latter. The nucleus leni nisei hitertilis, in recon-
struction, forms a long columnar mass, which lies in a trough.
(i|{(H'l'IN(l AND (lIAIN'lNli T()(JKTII Ki; ()F NKlKoNKS. ,s4'
incMlial from it, iiiadi! by tlio fibres of tlic latcnil Iciiiiiiscus.
Kainoii y Cajul divides tliis nucleus into an iMl'erior and a
superior part {ridi' infra).
'I'he nil/ifii/iis iiifcriiii- of the eorijora (|uadri;j;eniiiia, much
better devcdoped in man ami hij^iier mammals than in lower
forms, [)resents inside a very nuicii more distinct luudeus than
does the eoUiculus superior. This is km)\vn as the nucleus
eolliculi inferioris. On the lateral surt'a(U' of the mcsence[)lialon
the lateral lemniscus is visible as the so-called tri^ouum lemnisci.
'V\w colliculus iuf(!rior is connected witii the corpus fjenieulatum
mediale of the diencephalon throuj^h the braehiuin (|uadrij,'emi-
nuin inferius.
The cor/n/s f/rtiicii/fi/iiin inct/idic forms a small ovoid mass
situated nu'dialward from the lateral {geniculate body at the
junction of the mesencephalon with tlu; dieiu'cphalon. On its
surface is situated a superficial layer of white substances which
staJuls in relation to the medial root of the tract us opticus
(comniissura inferior (iuddeni), and also with the brachiuni
I'ltlvhiiir.
/ i Corpus (iPiiirnUitinn iiKiliiil)'.
i^. I / 2ir(icliiHmii}i(iilriii<'miiniiui)if(r,'ui!.
%K. ^'<- -
Colliritlua siiiivrioi:
/ AijKcduct im ifrcliri.
fir:
.0
Corpus genicula turn htternle. [
A'i»7<iis iioati'niir Ihdlatin
\Decuss(ilio hrachii
conjunct ivi.
i\ucl<us iiiisKiiiir iiKiiann. j
Fid. 540. — Frontal scctiini tlir(iii«li m iKiriiiiil liuinan lii-ain at llic level nf deciis-
siitio l>racliii (■(Hijimelivi. i.M'terC. vim Mctiiaknw, Arcli. I'. I'syeliial.. lierl.,
I?(l. xxvii, ISlCi, 'i'af. ii, FIk. 1(1. i N,, leiiinisciis superior {ohcre Srlilrifi''i ; >'...,
main portioti of leinnisciis iiiedialis i llitiijilllieil dir SchleifenscliicM ) ; x. lateral
white matter of lateral yeni<'ulate Ixxly.
quadri^eminuni inferius from tbe colliculus inferior (Fiu- ^M)).
Inside the capsule of white matter is situated a ^vny mass
known as tbe nucleus cor])oris geniculati medialis.
The topograpbi(!al relations of the nuclei terminales of the
cochlear nerve have been described in Chapter XX. Will,
where the peripheral auditory neurt»nes were considered. The
diflferonce in tdiaracter between tbe nucleus nervi cochlearis
1
.4/ i
In
ii
tU
i^ i
II. i
848
TIIK NKUVOIS SYSTKM.
V('iitralii< luul tlic iiuclous iiorvi rodiloaris tlorsulis woro rc-
ferrt'd to in tlu' siune cliiiiJltT.
The iiiftii'iin iU'rri ntrlih'O' ri'/ifnihs can he sulKlividod into
two parts: tlio anterior jiart or licatl, and the postfrior i)art or
Vui. 541. — XufU'Us N. coclilcii' Vfiitnilis of a lU'wlxirii ciit. (At'tiT S. Kanioii y
Ca.jal. Ht'itray; zuni Stiiilium dcr Mi'diilla OlilmiKala. clc, Hi-fslcr, Lcip/,.,
ISiKi, S. SI, Kii{. -ilA.) .1. aiitcriiir liiiitioii dI' liliclciis : />'. axolii's of X. cixli-
Ica' ; r, axcdit's (if N. vcNlilxili ; />. tractiis spinalis N. tiiKfiiiini : /■-', I'lupus
trapfziiidcmu ; d. axoiic I'miii cfll luxly in ninlciis fioinj; to curpiis Iraiic-
ziii(U'mii and fjivinj; (ill" a rnllatcial which runs dmsilward ; /(. axmu' with
CDlhitcnil niuninf; tn tiic anterior purlion of tlu' ventral nU(dens ; c. nn-
liranched axcine K<iinK directly into the corpus traiiezoideiiin ; (/.another
axone with collateral passing dorsalward ; c, end Imlh of axone of N.
tochU'iu.
(iU(>riMN(i AND CIIAIXINli ToiiKTII KU (>K NKCKoNKS. S4!)
"i^
tiiil <»f tlif imclt'iis. 'Pile cells in tiic tail iiii' souicwlmt less
rc<;iilar and ratlu-r lar;,'('r tlian tliose in tlu' lioad. In liotli if-
<;i(ms they jxissi'ss luiiiu'roiis dcudritt's, which l)raiich niaiiifoldly
in the j,M'ay matter. The niedullated axones of the cells .situated
in the anterior or head portion of tlic nucleus (Fij;. A+l) pass
forward and niediulward in a rather narrow huiidle to enter the
trapezoid body, wlu-ri' they s})read out to form the transverse
fibres of tliis structure. The axones arise usually from the cell
body, but occasionally come olf from the dendrites at a consid-
erable distance from the cell, a fact to which 1'. Martin
attributes Sala's mistakin<f certain of the cells of this nucleus
for spinal gan<rlion cells. As Held has shown, not all of the
axones from the ventral cochlear nucleus j»ass ventral to the
corpus restiforme into the trapezoid body ; a certain number of
them, those in the tail portion of the nucleus (Fig. 54'^), fjo
dorsal to the corpus restiforme to plunge down again medial-
ward and forward to enter the corpus trapezoideum, passing
either medial to or lateral from the lil)res of tiie tractus spinalis
nervi trigemini. Some of these fibres give off, in passing, col-
laterals to the nndeus nervi vestibuli lateralis of Deiters.
The axones from the nucleus nervi cochlearis ventralis, having
arrived in the corpus trapezoideum either by a j)ath ventral to
the corpus restiforme or by one dorsal to that body, proceed, as
a rnle, through this structure to the region of the superior
olivary complex of the opposite side, where they turn to run
forward in the opposite lemniscus lateralis.* \ot all the
axones, however, from the ventral cochlear nucleus jro into the
lateral lemniscus of the opposite side. ^lany of them a])pear to
terminate in the nuclei of the superior olivary complex of the
same side and more of them in the nuclei of the superior
olivary complex of the opposite side. Further, a few in all
probability run to terminate in the nucleus nervi coclilearis
ventralis of the opposite side, for, ])esides the terminal fibres of
the cochlear nerve, there are to l)e made out within each
ventral cochlear nucleus terminal axones arriving from tlie
trapezoid body.
*Tliis is difficult to briiif; into accord with von Mouakow's statement
ttiat after spctioii of tho lateral lemniscus in younjj animals there is no
atrophy <ir dejieneration of the trapezoid l)ody. The conllictinjr results of
the various invcstifrntors are earefidly c'om|)ared and subjected to a searching
criticism in the article of Held, 1H!)1.
■f
!■'. 1
s:.(t
Till-: NKUVolS SYSTKM.
Fi<i. 543.— Vurlfi t<'nnin;i1('s of tlic \. (•(iclilciv of :i four-day-olil nibliit. 'After
S. I{;iiiic')ii y (':i.i''l. H''itr;i<; /imi Stiidimii dcr Mcdiillii (>lil(iii>;iit;i. lircNlcr.
Lcip'.. IXiKi. S. S4. Fji;. 'J2.) .1. nurlciis N. coclilca- vciitnilis; /f, ciiiKliil por-
tiiiii of vfiilral imclcus ; ('. imclciis N. coclilcn' dorsiilis (tiiln'rciilimi atusti-
(•uiii>; K. t'orpus n'stiforiiic ; l<\ tr.ictiis spinalis N. trii,'i'iiiiiii.
(lIloiriMM! ,\NI> ('IIAINrN(i TOOKTIIKlt <H" VIM 'HONKS. HOI
'I'lic iiiit/riis mrri nii/i/rir r/«/".y«//.N, ol'tfii s|nikfii (if asllic
tiilK'n-iiliiiii ii('iiriti(;iitii, is ulctillikf riiuHH of^riiy iiiuMi'r \vni|i|ifil
;il»(iiil the (Iniso-liilcnil siiffiicf of tlio coriniH n'stironiic. In
tniiisvn'sc sci-tidii throii^rli tlit* rlioiiilM'iicfpliiildii this niiilfii.i
ii|i|i<-iii-s to III- (liviilcil into llin-c /oiifs, of wliirli the inidtllc ono
in almost, ciilircly l'rc(! fnmi iiicilulhitt'd lildos. '\'\n\ iiif<liillut(;(l
iixotics of \\\i> vvWh Hitiiiilcd licrc all pass dorsal to tliC! (corpus
rt'sliforriK!, I»iit IIh- liltrt'H can l»c divided into two ;,'roiips : (^^)
those wliieli enter tli(! stria> niediillares to pass to the middle
line, then* to deeiissiite with similai tihres from tli(> opposite side
and to dip d<twn and heconu! involv(Ml in llie superior olivai'y
eompl(!X, the impidses nltimately finding' their further eoiirse
forward in all prohaltilit y throii;,'li the tihres of the lemniscus
lateralis, and (//) tlntse which, instead of (tnlerinj^ tl)o stria; me-
didlares, plunf^cs directly downward to arrive in the superior oli-
viiry ('oiiipl(«x, the trapezoid Ixtdy, or the liitiTul lemniscus. The
former j^roup represents the dorsal path of Hold, and the latter
jfroiip the ventral path (»f Held from the dorsal cochlear nncleiiH.
It is thus seen that from hoth the ventral coehleur luicleus
and the dorsal co(dd((ar nucleus we hnvv to (hial with a dorsul
and a v(!ntrai path. The exact termimitions of the axones has
not heen clearly iriade out for any ouv of these paths. How
many terminat(! in the j^'ray matter of i\u'. supcM'ior olivary com-
plex of the .same side or of the opposite si(l<! i.s not yctt ci«'ar ;
and how many fi})r(!S, if any, are dinurtly continued on into the
lemniscus lateralis of tlm opposite side; or of the same side we
do not yet know. It seems certain that the majority of the im-
pulses coming out from the nuclei ti-rmiiuiles of theco(;hlear
lUM-ve on one side ultimately travel forward directly or indirectly
throufjh the lemniscuH lateralis of the opposite side. That a
certain proportion of tln^ impulses pass up on the same side
.seems, however, to he ^renerally acrcepted.*
The best {general description of the ninh-ns oh'vnris superior
.since the articles of .1. Lockhart Clarke, Sehriider van der
Kolk, Dean, and Si)itzka, is that of von KoUiker.f The nucleus
* For a report on im iiitiMvstiiif? case of jiatliolof^inal iinplicjutioii of tlm
iiiiflci of the coclilcar iicrvt; the reader is referred to the artieie hy Adolf
Meyer. Anatomical Findings in a Case of Facial Paralysis of Ti'ii Days
DiM-atioii in a (■eneral I'aralylic. with H. ■marks on the Termination of the
" Anditory " Nerves. J. P^xper. Med., N. Y.. vol. ii (1897), pp. 607-011.
t von K<>l!iker. op. rll.. S. •,'():; If.
I
m
r;
lit
852
TIIK NKinOlS SVSTKM.
is iiiiich smaller in Iniiiiaii liciiins tliiiii in iiiiitnals. l-'lcclisifx,
ill liis li'i'turi's (luring the siinuiicr scnicstcr of IS'.ir), suj;<,'('st(Mi
that tilt' nucleus olivaris siipcrioi' nii;j.lit be oonccnu'd with the
itiiu'rvation of I he niusclfs of t he car, inasimich as it is iniicli
larircr in animals that havi' larirc, very movable ears. It is
described Ity von Ki'dlikcr as consisting; of three portions: a
lariicr nic(Iial portion, and two lateral cylindrical masses, its
situation in the pons is vcntro-medial as rej^ards the nucleus
iici'vi facialis. It is surrounded by and partly imbedded in the
iilires of the corpus Irapczoidcum. The structure is most easily
••'iidicd in the nuMlulla of the cat or rabbit ; ac(!ording' to Spitzka,
.. is hiirhly developed in cetaceans.
In the nucleus olivaris superior are situatctl a very larj^e
number of nerve cells which send their axoni's in various direc-
tions, while the nucleus ri'ccives terminals and collaterals in
enormous numbers. 'I'lie attempt has been made to establish
the relations of the nucleus to other portions of the nervous
system by studies with the embryolofjical method of Flechsi^',
with secondary degenerations, and with the method of (Jolj,n.
The researches of Fhudisii^ and von Metditerew show a corre-
spondence in myelinization of a portion of the white mutter of
the superior olive to that of tin; irapezoid body and the lateral
lemniscus. \'on Hechterew has further postulated (from
studies of myelinization) a connection of the nucleus olivaris
superior with the nucleus fastifrii throuf,di a bundle which
passes throufih the medial part of the corpus restiforme. lie
has also described a connection between the nucleus olivaris
superior and the nucleus nervi abducentis by means of a bundle
of fibres, which passes out of the dorsal portion of the superior
olivary nucleus, runs |)arallel to the root fibres of the nerviis
facialis, and goes to terminate in the nucleus nervi abducentis
This bundle is known as the peduncle of the nucleus olivaris
sujierior, and is shown in its first portion at least in the accom-
panying figure (Fig. r>r.\) taken from von Kolliker's text-book.
According to Baginsky, if the cochlea be destroyed in a
newborn animal there results atrophy and disa])pearance of the
cells and white iiuuter of the nucleus olivaris superior of the
same side. Von Monakow found that, on cutting the lateral
lemniscus on the right side in the cat or dog, the dorsal white
matter of the right iipi)er olive atrophied and disapjicared.
Not all of the white matter, however, of the upjier olive stands
I h
(Mv'ori'lNd AM) CIIAIXIXO 'nKM'yniKK (»F NKl'WoXKS. So3
ill rcliitidii to tilt' Ijitcfiil Iciiiniscus, iiml, wliiit is iiKirc, section
(ti'tlic lateral leimiiseiis leads t(» atropliy and deiieiierat ion (d'
only ii portion of the cells in the nntdeus olivaris siijicrior.
N'oii Moiiakow, therefore, holds that the nucleus olivaris su-
perior stands only in ])art in relation to the leiunisens lateralis
(d' the opposite side, the fibres conci'nicil passini;- through the
doi-sal white matter of the olive and oei'iipyini,' the dorsal field
in cross sectiotis of the lateral lemniscus.*
r-^^
Fit;. 511). — Cross scctinii tliroinrll tllf ilmsiil pio't nf tlii' imiis ilt llir level (if tlic
iiiicleiis N. (■(iclileie velilnilis. (At'ler A. viiii Kiillikir, lliindliiieli der
(iewelielehre. VI. Allll.. ltd. ii, I.eip/.., Isdti. S. -M^. Via. ls;5. ) l>, iMleleu> N.
veslilinli liUiTiilis (l)eiters ; /•'/, Inseieiiliis l<mf,'itililiii!ilis iiie'li;ili>; Fill.
ventrieiiliis <|1Imi'1iis: mi, iiiieleiis iilivMiis sii|ieriipr ; Stu, |)e<limele ol' iiiieleiis
oliviiris sii|ieiii)r ; 7V, i'i>r|iiis tniiiezniiletiin ; I', tiiictiis spiiiiilis N. tii>;eiiiiiii ;
Xr. N. vestilmli : 17, nidix N. iiliiliii cnlis ; 17', iiiicleiis N. ididiiceiilis ; 17/,
Iiiieleiis N. r;ieiiilis; 17/', nidix N. IU<iiilis, piirs |iriiii:i ; 17/'^, I'iidix N.
fiieiiilis K'liii ilileiiiinii ; 17/'. nidix \. ('iiei;ilis, |i:irs seeiiiidii ; 17//, lilifleiis
N. eoelileie veiiliiilis; 17// , nidix desceiideiis N. veslilmli.
The studies uiidi'rtakeu hy the (ioliri mi'thod have led to
somewhat more satisfactory results in this rei,noii. These have
heen carried out hy Held, von Kidliker, aiul Kamon y Cajal.
Without going into a detailed doserijitiou, the following gejieral
statements may be made : The cell bodies in the niu'leus oli-
varis superior resemble a good deal in type those of the luude-
* vmi Moiiakow. (', Stria' .\<'iislii'ir iiml uiitcre Sclilcife. Anli, f, I'sy-
c'liiat.. lierl.. lid. xxii (\s>M)). S. l-2»).
■>
m
854
TIIK NEIt vol's SYSTEM.
US olivaris inferior hiuI tliose of tlic nucleus dentatus of the
cerebellum, 'i'hey possess numerous much-brjinched dendrites,
wiiich are turned toward the interior of the nucleus, the axones
being directed in the main toward the periphery of the nucleus.
The axones of the cells, according to Kamon y Cajal, pass in
three directions : (1) The majority of them, after giving off col-
laterals in the nucleus itself, pass to the dorsal surface of the
nucleus, and then turn to run vertically (either by bending or
by bifurcation) in a longitudinal bundle, which is continuous
witli the lemniscus lateralis of the same side. (2) A certain
number of axones much curved inside the nucleus leave the
latter at its lateral border to enter the trapezoid body, where
they can be followed nearly as far as the nucleus nervi coch-
learis ventralis. Held describes similar axones as actually ter-
minating ijiside the ventral cochlear nucleus. (;}) Other axones
arising in tlie nucleus olivaris superior pass out at the medial
side of the nucleus to enter the plexus of the nucleus prsvoli-
varis, there to mingle with the fibres of the trapezoid body,
h'urther, according to Held, axones can be followed from the
cells of the nucleus olivaris superior directly into the nucleus
nervi abducentis, these axones doubtless corresponding to the
bundle which has long been described in Weigert ])reparation8
as the peduncle of the nucleus olivaris superior.* It is not un-
likely that such a path is of importance in connection with the
acoustic eye muscle reflexes.
Terminating in the nucleus olivaris superior can be made
out many fibres from the corpus trapezoideum. Many of these
are doubtless terminal fibres, but the main mass of them con-
sists of an enormous number of collaterals given off almost at
a right angle from the transverse fibres of the corpus trape-
zoideum. These terminals and collaterals, together with the ter-
minals and collaterals which enter tlie nucleus from the for-
matio reticularis, and the collaterals from the axones arising
from the cells in the nucleus itself, form a dense plexus of
fibres as complicated, perhaps, as any met within the central
TUM-vous system. The accompanying figure illustrates well some
of these relations (Fig. 5+4).
The nnchuK corporis frnpezoit/ci is also better developed in
other mammals than in man, but can nearly always be distinctly
atiel dcr klchii'n Olive of tlie Germans.
ip
GUOUPING ANO CHAIXINO TOCrETIlER OF NEUIIOXES. 8.55
■ the
ritos,
cones
ileus.
88 in
ITcol-
)f the
ng or
nuous
ertain
ve the
where
. coch-
ly ter-
iixones
metlial
pritoU-
1 body.
om the
lueleus
to the
rations
not un-
'ith the
\o made
)f these
>in con-
most at
trape-
Ithe tor-
;he for-
arising
3XU8 of
I central
In some
loped in
Istinctly
made out. It is situated ])etween tlie nucleus olivaris superior
and the root fil)res of the nervus ahducens, the cells which com-
pose it lying in among the fibres of the corpus trapezoideum.
In this nucleus terminate many collaterals from the transverse
fibres of the corpus trapezoideum, and a certain number of ter-
miiuil fibres which come from the region of the raphe. In ad-
O.m
Fio. 544. — Tniiisvcrsc soctiiin tlimiiKli tlic vcntnil part of the nucleus olivaris
superior wit li the adjacent tibres of tlie corpus trappzoiileuni of a newl)oru
cat. Method of (iolj,'i- i After A. vmi Kidliker, Haudbuc li der ( Jewelielelire,
VI. Aull., Hd. ii. Leipz., ISitli, .S. •_>ti7, I'i';. ISO. i 17/, radi.v N. facialis, pars
seeunda ; Ol, lat<'ral lolx' of nucleus olivaris inferior; O.oi, medial lohe ; /»•,
axones in eor])us trapezoi<leuui : ti\ bundles of eollatenils from trapezoi(i
axones passing into luuleus olivaris inferior; tr::, cells of nucleus corporis
tnipezoidei ; tr::\ a."ioues to the same.
dition there terminate in this nucleus a certain number of
rather large thick axones which, on coming into contact with
the cell bodies situated in the nucleus, expand into tliose pecul-
iar end-plaques or acoustic calyces which were discovered by
Held, and which have been so carefully studied by him and by
Ramon y Cajal. The latter fibres come from the region of the
raphe, possibly from the nucleus nervi cochlea' ventralis (Ra-
mon y Cajal), or possibly from the nucleus corporis trapezoidei
of the opposite side (Held); they enter the nucleus of the
trtipezoid body , where the axone widens and spreads out to
form the yellowish, almost homogeneous, cup-shaped expansion,
which fuses with a spherictd cell body inside the nucleus.
Ramon y Cajal has compared this plaque to the Tasfmvuixken
(of Merkel), and to the ivy-shaped endings which Ranvier has
66
I :
.'^1
856
THE NERVOUS SYSTEM.
A
«SS:^
B
"■■<«.^.„
sr
■■fi
>
M:
GROUPINO AND CIIAININC} TOGOTIIRR OP NEURONKS. 857
Ihinhit,
(ilhi riiiiiii.
Terminal uj-diio
described in the skiti. Tlu'se axones termiiiiiting in acoustic
calyces on the cells of the trapezoid nucleus are much larger
than the axones arisiiig from
the cells of tlie nucleus. It
is possible to stain them with
haematoxylin and carmine in
ordimiry sections (Kamon y
("ajal), and recently they have
been stained in the newborn
guinea-pig, rat, and rabbit with
methylene-blue (Semi Meyer)*
(Fig. 545). Held has recently
undertaken again the study of
these structures by the most
careful methods, and has util-
ized his results to support his
doctrine of concrescence as one
mode of interneuroiial relationf
( Figs. 54(5 and 547).
Under the designation tiuclens pneolimrLsy Ramon y Cajal
includes the mass of cells lying ventral from the nucleus oli-
varis superior and lateral from the nucleus corporis trapezoidei.
This nucleus is included by most writers in the nucleus of the
trapezoid body, but its cells are much larger and are of ditt'er-
ent shape. Tlie dendrites are large and manifoldly branched.
The axones pass into the lateral lemniscus in its medial part
(Fig. 54S). A few axones pass lateralwanl, perhaps, to form an
association path between the nucleus pi'ieolivaris and the nuclei
terminales of the co'Idear nerve. The curious calyxlike end-
ings characteristic ui the nucleus corporis trapezoldei are not
found in the nucleus prsvolivaris.
Still another nucleus in this region is defined by Kamon y
Cajal. He describes as the iiifch'iis .yciin'In/ian'K a mass of nerve
cells situated just ventral to the convexity of the nucleus oli-
1
Auoiif of (I'll
Fid. 51(1. — (ill liniii nucleus corpDiis
triipczoidci of ncwlidni cat. i .Vt'lcr
II. Hclil, .Krch. r. Aniit. u. I'livsinl.,
.\iiat. .\l)t!.., 1SU7, Taf. .\ii. Via. 2.)
l''i.\aticiii witli van (icliuclitcn'.s
mixture; staiuiuK witli iniu lucnia-
td.xyliii. Tlic lai'trc axcmc is sccu
tcrniiiiatiiiK U|)i>u the cell and ex-
liihitiuK what Held calls cdiicres-
cence relation. The small axone
with itsaxone hillock isaiisiiiK from
the cell liody shown in the liKure.
* ^foyer, S. Ucbpr cine Verliiiiduiitrsweise der Neurniieii ; nehst Jlitt-
hi'iluiifjeii uebor die Teeliiiik iind die I-'.rfolj^e dcr Methode der sul)uiitaiien
Metliyleiildiuiiiijeetion. Airh. f. uiikr. Aiisit., Moim, I?d. xlvii (1800), S.
734-748.
f Held, IF. 15oiti-iij;o ziir Stnicliir der Xerveiizclleii iind ilirer Fortsiit/p.
Zwcite .\hliiiiidliiiifr. Arch. f. Anal. ii. Physiol., Anat. Abth., Leipz. (1897),
II. iii and iv, S. 257 II.
i'i''' '■%
Wl,
I
%
u
E i-i.
S'^
«>
'! '
I)
i
'l •
858
TlIK NKIiVOUS SYSTEM.
varis superior, pmbraclnf? its vontral surface {Fig. 549). The
cells in this cresccntic mass are stellate, triangular, or spiTulle-
sluiped ; they are separated from one another by interspaces in
r"zf
W'l
, ,f ■/■■■ ,>•-•"■•> -
Fl«. !H7. — Cell of the iiiiclciis cdrporis tnipcZDidci of an adult rahhit. Fixation
witli van (■(■huflitcn's mixture ; paratlin scctiou 1.5 niirroiis tlii<'k ; cvytlirosiii
inctliyiciic-liluc staiuiiiK. (Alter H. Held, Arcii. 1'. Anat. u. I'iiysiol., Aiiat.
Ahtli., Leipz., lSi)7, Tat", x, Via- .'5. ' Tlic axis cylinders In) wliieli K'> 1>.v tliii
coll are stained liDinDfieneously ; the fibres (6) terininatiiif; in the cell t'on-
tain larK(^ innnhers of isolated neurosomes; the hiwer liorder of the cell
inclosed hy the terminal axone shows very distinctly a most intimate
union between the axis-cylinder i)rotoplasm and the Ki'i)und snhstance of the
cell body, since here the sime plasma layer isc<immou to both. On the ripht-
liand side the c.vtosponKium is wide uieshed owinp to coarse vacuolization on
account of which the axis-cylinder terminal looks to he more indei)endent
from the rest of the cell mass.
which an enormous number of collaterals are distrilv 'ed. The
axones of the cells situated here are extremely difficult to follow,
but appeiir to run latertilward to become associated with other
fibres of the corpus trapezoidtuim. The nucleus is characterized
definitely by the entrance into it of two or more bundles of
collaterals of such extraordinary delicacy that Ramon y Cajal
considers them to be Avithout doubt the finest in the whole ner-
vous system {n iji the figure). There are usually two such
bundles, the lateral ])eing somewhat more voluminous than the
medial bundle. They have their origin in the more superficial
and delicate axones of the corpus trapezoideum, from which
they come off almost at a right angle. The terminal branches
of these collaterals inside the nucleus semilunaris are so ex-
tremely delicate and so closely interwoven that they can be
fiiHif
The
j follow,
\\ other
kerized
Idles of
ly Cajul
->le ner-
|o such
lum the
lierficial
which
ranches
so ex-
lean he
GROUI'INCJ AND CHAINING T()(JKTIIKR OF NKUHONES. 859
made out only hy means of the hi<,']iest powers of the micro-
scope. In ^iolfjfi preparations they are so tine that they do not
stain of a black c()U)r, hut look yellowish, and resembk' minute
pi'arly tlireads. Tlicsc handles of collaterals extending between
the trapezoid body and the nucleus semilunaris are easily visible
in Weigert-Pal preparations. 'J'hey are often mistaken for col-
laterals which go to the nucleus olivaris sui)erior, but Kamon y
Cajal insists that the latter arc (|uite dill'crcnt from tliose under
discussion, inasmuch as they are much coarser, and have their
origin in deeper trapezoid fibres (C in the figure).
luliircatt's ; c, coUiitciiil Inmi mikiIIk r tiliiT ut tlic sunt' suit lor tlic iiiiclciis
jiniMilivaris ; (?, cell nf the imclciis pninliviiris tlif aximc of wliich iippcars
to K" latcraUvard ; t\ cells the axoiics of wliicli ;;o to the while sulistaiice to
form an ascending path u/, <i, <i < : f, m, j, cells of the nucleus olivaris sujierior ;
n, lailix N. facialis, par secunda.
From what has gone before, it will he seen that the corpus
trdprzoiili'um is a very complex structure containing mediillated
axones of very diifereiit origin, and probably of very ditfercnt
termination. Von Krdliker thinks it probable that the nuijor-
ity of the transverse fibres represent medullated axones arising
from cells situated in the ventral cochlear nuclei of the two
860
THE NERVOUS SYSTEM.
H
J ,1
h:''\
Bides. Rut, in addition, there are undoubtedly fd^res from tlio
nucleus nervi (HXiideiiris dorsidis of eiicli side, from the nucleus
corporis tnipezoidei, from the nucleus oliviiris su])erior, from
Fig. 549. — Xiicloiis s(Mniliiiiaris of ii iicwliorn cat; method of Golsi. lAftorS.
Itiinioii y (!ajiil, HcitniK zmn Studiuin der Medulla OhloiiKata, etc., IJri'sler,
hei])z., ISilti, S. !(0, Fi<;. ^;5((. ) .1, main porlioii of niieleiis semilmiaris; /?,
nucleus olivaris superior ; (', coarse collaterals ending in the nucleus olivaris
superior; <t, huudle of very fme collaterals \vhi<'li fj" to the nucleus semi-
lunaris ; It, delicate superlii'ial tihres of the corpus tr.ipezoideum ; c, terminals
of axones in the nucleus olivaris sui)erior ; (/, s))indle cells of the nucleus
olivaris superior, the axones of which }{o into the liilus.
the nucleus pntjolivaris, and possibly from the nucleus semi-
lunaris.
The finer structure of the lateral leitiniscus must next be
(After S.
., Hn'sliT,
hitiaris; /?,
i'\is oliviiris
•lens souii-
!•, toniiiuiils
ho nucleus
HIS seim-
noxt be
OHorPIXU AND C'lIAIN'INTi TOGETHER OF NEUIIONES. sfil
roiisidorcd. Tlio nuMluUiitt'd fil)r('s of whicli it cnnsista aro sop-
tirati'd from one aiiutluT hy ishiiids of j; ray iiiattcr. The j^ruy
masses form two main nuclei : the nucleus lemiiisci lateralis in-
ferior, whicli is directly or almost directly continuous with the
nucleus olivaris inferior, and which extends for a considerable
distance upward, and the so-called nucleus lemnisci lateralis
sujHM'ior, composed of a number of f,'ray masses more or less
separated from one another, althou} with high powers minute
columns of cells can be seen connecting this nucleus with the
lower one.
Umiix (U'svi'mlfun .V. triijinnini. yorimitiii ii'tirulml^.
' I Fiinriiiiliixliiiiiiitiiiliiiitlis iiiidiiili^.
\ i ! Ktifli.r ih'sfiiiih'iin meseiirejihitliva
,' . A. triijrmiiii.
Uritchium rniijinutiriiiii.
Hnirhiiiiii (■(iiijiiiirtiru)ii. ,
Jjfiiui. hit. w). /
•'• ■ .V,. ^ . ^ \ f. p , J , iiriitniunt rDiijiniiiiruni.
Nuch'us leDiiii.ici littciitlin.'y-^'^ ^-i^jfi.^ '.. /' '. \ ./-.-^
u,nn. .„t. uo. v^, g.^ - Y^Jyr % :)
1.,-mn.lat.ih)...^, V-'-^<Vv ' ' ■• ' ' M *'■''' - ■' wM-
Liniiii.icHs Uiliralin.' \ "^ ■*•
lirdihiinii jumfis.' ^ ■<»^^;ii^i4^v^.-jjif*Ei-'
l''iisririili j>ynimi(l(ilf«.,'
Li'iii nisiiis Id li-riilii
I jiiiitly iitropUir).
I f^ftmihruK iiifidiiitis,
Fui. TmO. — Cut's Imiin lifter section lit" Ifumiscus lateralis mi ri^lit side; fnintal
seetidii tliniutili the iiciiis .just iiifei-iiir t<i tile edilieiilus suiieiiiir. (After ('.
viiu Mdiiaiiciw, Areli. f. I'syeliiat., lieri., i'.d. xxii, 1S!)(), Taf. i, \"\si.l.)
The most careful studies of secondary degeneration follow-
ing lesions of the lateral lemniscus are those of von Monakow.*
lie concludes from his experiments that the fibres of the lateral
lemniscus can be divided into live portions :
(1) A portion connet^ted with the stria' acustictt (Fig. ')f)0,r).
(2) A portion connected with the nucleus olivaris superior
{Fig. ooO, r).
{'.]) A portion connected with the ventral decussation of the
tegmentum (Fig. SoO, d).
(4) A portion connected with the nucleus lemnisci lateralis
(Fig. 550, rt).
(5) A portion consisting of very short fibres (Fig. o.lO, h).
* voii Moiiakow, C. Oji. n't.
iin
6 :
' .* i\
■
sr.2
TIIK NEKVors SYSTEM.
The first portion, that (•(niiiooted with tho strinp aousticit, he
thinks, serves to connect the nuch'i terininales of the cochlear
nerve with the eerehrnin. The rej^'ion <»f tiie hiteral h'niniscus
occupied hy tiiese liiires is shown in the (lia^^'nun (Ki{,'. .')'>()).
Von Monakow's statements rej^ardinj,' the jiortion of the
hiteral U'liiniscus connected witii the ventral decussation of the
tcfjinentuin are not very satisfactory. He helieves, however,
tiiat it is the medial portion of tlie lateral lemniscus which is
concenu'd. liater studies have, however, shown the correctness
of this view of von Momikow, and in Chai)ter8 LVII and LVIII
it will he pointed out that the fihres here mentioned are tho
axones of i-ells situated in the nucleus ruher. Tliey descend to
tlie spinal cord.
The fihres in the lateral lemniscus, which are connected
Avith tho nucleus olivaris superior, occupy the dorsal portion
of the lateral lemniscus, heing mixed with the portion of
the lateral lemniscus which is connected with tin* striai
acustica;. The hundle in the lateral lemniscus connected
with the nucleus lemnisci lateralis is situated in its central
portion. The fifth portion of the lateral lemniscus descrihed
by von Monakow as consisting of short lihres is probably con-
cerned in connecting neighboring masses of gray nuitter with
one another.
The lateral lemniscus has been studied by (Jolgi's method
by Held, von Kdlliker, and Kamon y Cajal. Held believes that
the medullated axones of the lateral lemniscus are deriv-d from
the nucleus nervi cochlcie ventralis of the same side and of
the opposite side, from the nucleus olivaris superior of both
sides, from the nucleus corporis trapezoidei of both sides, and
from the nucleus nervi cochletu dorsal is of botli sides by way
of the stria» acustica>. THs views concerning the relations hero
are well shown in his diagram (Fig. 5.")!). \'on KoUiker con-
firms these results in part, and states that he finds fibres from
the nucleus nervi cochlciB ventralis going to the lateral lem-
niscus of the opposite side to form its ventral part ; further,
fibres from the nucleus olivaris superior and nucleus lemnisci
lateralis of the same side. He also onfirms von Monakow's
findings of the relations of fibres in the ventral decussation of
the tegmentum to the lateral lemniscus. The strii^ ucustica?,
he believes, undoubtedly help to form the lateral lemniscus in
mammals.
!'.
a
niirrH from iin- Tor/.u* ^ni/,t'- .\. /iiikiIih
ilfiia ruhrr Id ziikO-uih. , ". .V. (rif/cminii
— 6!
" H 1
^- =H
=-- 3
- T s
r K
i.fs
r 4'
^: -i
^ tr
X .. *
Z ~>
■~ n
zi — ?■
;•
?^ «r
* — "5
3 .*-^
3
> ■?
■?
U- — '
:3, r.
-t
-I -*
-.<n
^
t
iif
Corpus trapezotdeum
■i^:
m
K<{4
TIIK NKIIVOI'S SVSTK.M.
How miiiiy lil)n'.s of tlic liilcrul IfriiiiisciiH iirc uHcoiKliiif,'
iixoncs jirirtinj^ in nuclei lo\<a!r down, iind how injiiiy represent
(loscondin^ iixones, in not yet fully dcM-ided. (Jertiiinly tint
majority of lilirea ascend and reprctsent an auditory conduc-
tion path. That some lihres (h'scend seeruH (rertain, from the
studies of llehl, hut further investij^ation is m-cessary to
determine their exmit numhor, their origin, and their terminal
relations.
The studies of Itamuii y (!ajal with re{,'ard to tlie tinr/i'i of
flic hilrral Inniiisnis are helpful. II(! holds that while the
lower nucleus of the lateral lemniscus is anatomically continu-
ous with the nu(!leuH olivuris superior, it is nevertheless to he
sharply separated from the latter nucleus, for its (lonstituent
(U'lls are very dilTerent in shape, and the axones are entirely
dilferiint in their distrihution. The cells in the lower nucleus
of the lateral lemnis(!us are lar<^e, stellate, or spindle-shaped,
and possess lon^, smooth dendrites, whi(!h are much hranehed.
The axones of tlu^se cells, in contradiction to Meld, Ramon y
Cajal asserts, do iu)t asctend ; at any rate, in the majority of his
})reparations he found that they })as.sed medialward, appearing
to run in tlu* dinn^tion of the raphe, although he was not ahle
to follow the fihi-cs to their termination. The cells of the lat-
eral lemni ''nis come into conduction relation with an enormous
number of collaterals, \vhi(di comt^ oil" f ')m X\w fibres of the
lateral lemniscus as they pass by, a fact which has been con-
firmed both by Held and Ramon y Cajal.
The cells of the upper nucleus of the lateral lemniscus are
more s<!attered. Ramon y Cajal states that in general they are
spindle-shaped with polar dendrites, which extend transversely.
Here again the axones almost all go medialward, and, he be-
lieves, decussate in the middle line in order to help to form the
ventral decussation of the tegmentum.
There has been much dispute as to the nature of the trans-
verse bundles of rather fine fibres, which are easily visible in
Weigert preparations from the newborn })abe (Fig. 552), ex-
tend ijig between the lateral lemniscus and the region of the
brachium conjunctivum. Held assumed that these fibres rep-
resent(id medullated axones which ]«iss from the lateral lemnis-
cus to enter the brachium conjunctivum, and to follow a course
farther cerebralward, similar to that of the fibres of the latter
bundle. This view has been opposed by von Hechterew, von
r.U()UF»I\(l ANT) ('!IAININ(J ToOKTIIKIt oK NKl'UoNhX s<5r>
Kollikcr, iiiid Riiniuii y Ciijiil. A(!conliii;r to vnii HcclitiTow,*
tht'80 librcs piiHs to tlic lutcral Hurfucc of tlic stnitiirn j,'riHcutn
Cci.
Nu,
oll.in|.
Fkj. ."»ij. — Triinsvcrsc section (linpiiKli l)n»in :.!' ticwlidrii IkiIic. 1,cv(1 of cMlliciili
iiifcriorcs ofcoiiKpru i|iiii(lii«iiiiiii;i. ' Wriycit-I'nl, siiiis ii. sictiiin Ntp. )>SH). ^
.(</.(■<■(•., iic(UiMlurtiis (•( Tcliri ; a, (ihris riiiiiiiiiK fripiii lalcnil Icinniscii.s toward
dorsal lini'dcr ol' lirarhiiini loiijiiiiitiviini ; lli\ Coiij,, lirailiiiiin roiijiiiKtix iiiii ;
r.c.i. , coiniiiissiirf ItctwiTti tin rulliciili iiilVriorcs ; /Vc./.Vc/i.. vi'iilral pnition
of liracliiuin (01131111111x11111. wliirli in reality tonus a eoimiiissiiie liel ween the
superior liilelei of t lie vest it Hilar nerves of the two sides ; /•'./.hi., faseieiilii> lon-
gitudinal is media lis ; /•'./'//.. I'aseiciili lon;;iliidiiiales imiitis ' iiyraiiiidahsi ; /,./.,
leiniiisciis lateralis in lartti' part terniiiiatiiiH in the iiiicleiis of the collieiilus
inferior; /,.)«.. leiiinisciis niedialis; .V. /I'.. N. troelilearis ; .Vii. To//. I'/iy". nneleiis
colliriili inferioris; Xii.r.s.' h. niii'leiis centralis superior, pars lateralis;
.V1/.C..V.1 III I, nncleiis centralis superior, pars niedialis ; U.iLu. ('., radix desceiidens
[iiiesencephalica] N. tri{.'eiiiiiii ; Sl.ijrc, stnituiu Ki'iseiini centrale, il'repara-
tion li.v Dr. John llewetson,)
contviilc, and tlioiico run tiloiiij it towtird tlio raphe, wliore they
vanish from s'ww. N'on K()llil<c'r (h-nit'S any direct relation of
these fihres to the hrachiiim conjiinctivuni, and, on the contrary,
assumes tliat they represent arcuate fil)res. He describes them
as ptissing beyond the brachium conjuiK^tivuni, smd then bend-
♦ von Heclitorew.
(1894), s. iia.
Die Lcituiigsbalinuii iiii (ieliirn uiul Rik'keiiinark
t
iii
I
11
80(5
THE NERVOUS SYSTEM.
ing down oitlier latcM'al or inodial from the mesencephalic root
of the nerviis trigeniimis, in onU'r to form definite fibra*
aroniitiv intennt' (Fig. Sol}). Kiimon y ^'iijiil conld not find
these fibres described by KeUi, nor could he find any cells in
the nuclei of tlu' lateral lemniscus, which sent axones down-
ward, such as Held describes. We have frecjuently, in Prof,
flail's laboratory in Baltimore, observed fibres extending from
the region of the lateral lemniscus to the region of the brachium
conjunctivum, but have not been able, thus far, to come to
any positive conclusion regarding their ultinuite distribution.
LI-
FlO. .'>.^3. — Part of a transverse seetinii ipf tlie sjiiiial extremity of tlio eollieuliis
inferior ol' 1 lie cat. (Al'ler A. vnn Killliker, llandlmcli de (lewebeleiire, etc.,
VI. .\iill.. lid. ii, Leipz., 1S!»), S. T)!),"), Kif;. .Itit. ) i\, aciuednetus cere))ri ; iJa,
iiracliiuni C(in.jiine1iv\ini ; T;;, slraluni nriseuni eentrale; A', ventral limit of
nucleus colliciili inl'erioris : A'/,/, nucleus lenniisci lateralis; /,/, lemniscus
lateralis; (/, litres ninninK I'rom region (»!' lemniscus lateralis to become in-
ternal arcuate libres ; / I', N. troclilearis.
Tlie lemniscus lateralis, having arrived at tluMiiferior border
of the mesence})]ialon, passes in large part dorsalward, as has
been stated, to plunge into the colliculus inferior of the cor-
pora (|uadrigemina (Fig. 554). At this level the reciprocal re-
lations of the lemniscus lateralis, the lemniscus medialis, aiul
the bracliium conjunctivum, beconu> miudi altered, in the
pons the lemniscus lateralis is sitiuited close to the lemniscus
medialis, the fibres of the ojie l)undle going over into the
other without sharp limit. But from this point on the two
bundles are easily distinguishable from one another, inasmuch
as the lemniscus medialis continues its course without marked
change of direction, while the lemniscus lateralis turns sharply
dorsalward and enters, at least in large part, the nucleus col-
UUOUl»IN(i AND (ilAINING TOGKTHEH OF NKUIIONES. S07
Colluiihi.s sii/>t'n^'r
A. llircct system. (I'l'i-iplioral ;iii(lili/ry
sensory neiiniiies, or iiiiditory iii'uroiies
of the I order. )
; CAIicnliis infM-ior
' ,\«i7iVAs Icmnisci
'' tiit/riilis
N. cochlear
Intpncidci Corpus Irapnoidi'nm
Nucleus ntni cochleae ycnlrala
i'cllU-iiljis sii/hTi\'r
iWficiif path
I I'clliciiliis infcrU<r
Ji. Indirect systems. I .\iiditory iieii-
roues of II order and of liiKlit
ordeiii. )
Lemniscus laterulis
Xiidcunneni \\ Hr,icMntn
cochletw ilorsdlis
Nucleus iicnii coMcue \eiilmlis
S. cocMeat
i.Vucleus lemnis^i
I Ititeralis
Lemniscus Inlirttlis
Sncku9 oUvuris
siiperu'f
.Vitcli-u.1 tv/jfiT/jj inipi'ioijei
FlU. 554. — Seheines i'lo^tratinK termination of axones of N. eoelileie in the een-
trjil nervons s,\ , tonelher with some of the central andilorv neurones.
(.\fter H. Held, Arch. f. Anat. u. I'hysiol., Anat. Ahlh., Leipz., imi, S. L>40.
Fig. 15.)
* >ffi
i'
Mirf
808
THE NERVOUS SYSTEM.
liciili inferioris. The brachium conjimctivum at the same
level befjins to turn veiitralward, and a little higher up enters
into the decussatio brachii conjuiictivi.
The relations of the lemniscus lateralis to the nucleus col-
liculi inferioris are very characteristic, and lend an especial
stamp to tliis portion of the brain, so that Weigert preparations
of transverse sections through the inferior colliculus are recog-
nizable at first glance, when one is once familiar with the ap-
pearances. Tlie nucleus of the inferior colliculus sits like a
berry on a stem, the latter being formed by the diverging fibres
of the lateral lemniscus. A portion of the fiV)rcs pass over the
dorsal surface of tiie nucleus colliculi inferioris to decussate in
the velum medullare anterius with similar fibres from the oppo-
site side (so-called JIii-nk-l((})pensrhleife of Meynert). Von K<il-
liker believes that many of the fibres enter the frenulum veli
meduUaris anterioris.
Still anotlier portion of the lateral lemniscus passes by the
colliculus inferior to enter the colliculus superior, there to ter-
minate in the middle portion of tlie stratum griseum colliculi
superioris. This bundle, being one of the earliest to become
meilullated in the colliculus superior, is extremely easy to follow.
Doubtless these fibres are of no inconsiderable significance in
connection with reflex movements of the eyes depending upon
acoustic stimuli, inasmuch as we have seen that the superior
colliculus of the corpora (|nadrigemina represents the most
important subcortical central organ for the control of the eye-
muscle movements (Figs. 55.5-558).
And, finally, a portion of the fibres of the lateral lemniscus
probably pass forward tlirough the brachium ([uadrigeminum
inferius to terminate in the corpus geniculatum mediale or its
immediate neighboriiood.
Held describes fibres of the lateral lemniscus which pass oti
directly through the tegmentum, the hypotlialamic region, and
the internal capsule to the cerebral cortex (lleld's lUrcrtc arnx-
fisr/ic liiitdruhdlni). That such fibres may exist is not impos-
sil)le, tliougli that there are many such seems unlikely, since, as
von Kolliker points out, the experiments of von Monakow prove
that after removal of the temporal lobe in the rabbit and in the
cat no alterations result in the lemniscus lateralis even after
the lai)se of a long time.
The nucleus colliculi inferioris has, unfortunately, not yet
OKoriMN'O AND ('HAIN'IN(} TOCJETHKR OF NErROXKS. SOI)
['lit
.-i'e^
Collkiiliis iwperipr
A. RECURRENT SYSTEMS AMONO
AUDITOfiY NUCLEI. (HELD)
S'ttdtiis ncrti cxliUae donsalis
\m
Striae iiciisticae
!
.^Nucleus olhiiri.i superior 'K '^"P"'-'
Cortex
Colliciilns
\ inferior
Lemniscus
lateralis
Nucleus oUvaris
superior
»' I ' ■ . I.I . .. .,...,. ./:,. / " jyucteiis corporis iKpezoidiL
nucleus Item cociii^ne vciiiriiiift > ' r
Ccrpiis trapezoiileiim
B. REFLEX PATHS
(I) Optiir-iicoiuitii: reflex path
to eye-iiiiiscU's
(2) Acoustic rctlcx put/i to
CKciiil iiiii.''clcs
Colliculus superior
Sucl.N. m
(3) Ophc-<u\vi.':tic rcllex piillt to
rotator ttumcles ol'llie head.
Reyion ofdccussntio
leijinenti dorsalis M<.ynerli
NiuiAir-
A't/clcii.f tierii
ccs.'ilciio iter." til is
A/ucleus rtcni ;
•mitml from
trottus opticus
Auditory fihr*
^-' I
..-• Xiulciis oiiMirix .•superior'
Ccrpus trupczoidcum
S. cer\ icnii.-, I
\ Colliculus
\ inferior
Xiielcus
'Jcmtiisci lateralis
•tnniscus lateralis
■C^, Xiicleua oLintris Rupenar
X ruicunlus loiigitiidiiuilis tntdiulis
Flo. 555. — \. NcnroiKs with (Irsci iidiiiK mmiius. tlii' |icrikarycnis :iiiil <liii(Irit<'8
lit' wliicli iivoilUiUctl ill iiiiilii 111' till' < riitr;il iicuiislir iiatlis. 15. (»iiti(-:u'iiustic
rcll.x pullis. ( After II. lltlil, .\icli. t'. Auat. uiiil I'liy.-iiil., Aliat. Aiilh., 1893,
S. :.>ll. Kif;. Hi.)
870
THE NERVOUS SYSTEM.
( if''
a
been sufficiently studied to permit of more than fragmentary
statements regarding the neurones situated in it, and the dis-
Aljlh'il Ileitis -
cfivbr '
Strnliim firisiiim
cenlnilt
Xiicfeii.s
Xoiiilomolmii
Rmlik lU'.tcoiiilena
tm sau\phulica
ncni triygmini
Nilcltiis lemnixi
luturu/ts
I!:
1!'
' fiisciculus
' Uvwitutlinatis
meiliulis
Lemniscus lateralis
FiCi. 5r)f). — Scnii-sclu'iniitic dnnviiij,' illiisti-atiiij,' tlic rt'lations of the U'limiscus
latt'i-.ilis to till' corpoi-ii (luadriKt'iiiina. < After II. Held, Arch. f. Anat. u.
Physiol., Aiiiit. Abth., Leipz., IHUS, S. a% Fifj. 10.)
tribution of their axones. It would appear that there are con-
tained in it both inaxones (Golgi cells of Type I) and dondrax-
GIIOUPING AND niAININO TOGETIIRIl OF XKrilOXKS. 871
sntary
le dis-
commissura posterior
t acciutie
•kill fu'fi (ff'''<'>
- u'llu-uliis
inferior
lintnixl
■rut IS
U'liiniscus
Anat. u.
arc COIl-
lendrax-
Corpoiv fffnicttlata
V»(7i7/.« lalvnilis
nifurwr f/cc/ifit/i
■L'olliculllS flllKTWr
Collie III IIS
interior
tWmiilic niiciifaris
hniirU'iis hitfriilis iiu-rtius)
■W /.■'&"rNiicli-iii> neni vi'sliiii/i
\^:,;0; / luf.mlis (Dah-ns)
'■■iM''.-'
Kn-nuilii^ reliciilaris
I nucleus Uiteniln inlirior)
CiMiliniiiilioii in meiliillii oblongata.
frfmiiiiis oftiisciculi iii\'prii,
vi'ninil's- cl liiliTtilis , I'f llif
spinal cord.
fiiscitiiliis cerebivspinafis wntralia
Fiii^dculi proprii, ventral <si.'l lulcnil,'
■FiifcLiiliif^ ii-rt.'lvllo.'t/iitiiil's tli'iviili.t
flisdcii/iis Ci'ivbiv.yiniili -■ ^^^Z^^K^S^^^^ (direct ceivbeliar tnieft
Intenilis
Fuiiicnlus ihr.sti/i'i
Fl(i. 557. Sclicinc of the ('(Pinsc nl' tlic ciptic ami aroiisdc rctlcx paths in tlie.
I'liniiatio iiliculaiis. > Al'li r II. Ilclil. .Vich. I'. .Viiiit. ii. I'liy^inl.. .\ii;il. .Mitli.,
Lfip/,.. IMicl. S. :.'•,>!•. V"\)i. \\. ' Siifl. Ill, inulcus iicivi (iiiilii-niiitdiii ; Sii.f.l.m..
imclciis lasciciili lciii;;ilii(liiiali!t iiiedialis sen imi'loiis comiiiis.suni' [lostiTioris ;
Sn.r., iiucli'iis niliiT,
m
m
i:\
tl^^ l:
' i.
h
)')■■
\t''
i
i
872
TlIK NERVOUS SYSTEM.
ones ((i()lf;i colls of Typo H). 'Vhv loiifj axoiics apparoiitly take
two (iiroctioiis ; tlu' majority of tlicm ascoiid, passiiiff mainly
tliroiijTjh tlio brachiuiii (luadrigoiniiiiiin iiifcrius to j^'o, along
with the coTitinuatioii of the lateral lemniscus, to the corpus
geniculatum mediale. A few of the fibres which pass into the
brachium (|ua(lrigcminum inferius leave it again, according to
von Hechterew,* to decussate in the roof of the a<|ueductus
cerebri, and probably to terminate in the nucleus of the oppo-
site inferior colliculus.
. i* .
^^
/
Nudeiu olivarix
superior
IS triipezoidcum
NucleuA corporis trapezcidei
Fl<!. 558.— f'lii-ims tnii»'Zi>i(ltiiiti. witli iuljiiicnt masses of (.'ray matter on the ritilit
side of the liraiii ol'tlie laUtiit : metliod of(iol<;i. <'oml>iiietl iiieture. lAl'ter
II. Held, Arch. f. Aiiat. ii. Physiol., Auat. Ahth.. Leip/,., ISiCS, Tat', xiii, Imk.
(>. ) <(, etdl in luieleiis olivaris superior; /*, cell in nucleus olivaris siiixrior
acce.ssorius medialis. itsaxoiie noins,' through the peduncle of the upperolivi'
to the nucleus N. ahduceulis : c, axones of corpus lrai>ezoideum termiiiatiiifi
in nucleus corporis trape/.oidei : c «', axoms running; to terminate in sui)erior
olivary complex.
Held found tluit another portion of the long axones arising
from cell bodies in the nucleus of the inferior colliculus desceiul,
and piiss by way of the hiteral lemniscus to the various nuclei of
the auditory path situated below this level. That there must
be other connections of the inferior colliculus seems very likely.
voii Bechterew. Op. cil., S. 114.
II
OliOl'IMNG AM) CHAINING 'nxJKTIIEIl OF NKUKONES. 873
take
uinly
lion}?
Dr\)us
o tlu'
Ilfr to
lU'tUS
oppo-
cleuf ofiraiis
supirior
f-
nalio nticutaris
tnipezoUleum
the v\il\\\
.Alter
xiii. I'i^'
sniM'iiiii'
ji|ici'<ilivi'
itiiiiiatiiit;
II suin'ritir
iirisinsr
ucloi of
ro must
likelw
and tlie impression is j^n-adually j^Mininj,^ ^m-oiukI that this quad-
rigeminal hody is of tiie liighest sit^niifit-ance for the settinj,' free
of reflexes in connection with auditory stimuli. It appears to
stand in the same rehition to the auditory conduction ]tath as
does the superior coUiculus to tlu' visual fonduction path.
It will he of the {.(reatcst importance in the future to deter-
mine exactly the relation of the inferior coUiculus to the most
direct acoustic path which extends from the ear to the cortex.
Do the auditory tiltres carrying impulses concerned in sharp,
clean-cut visual sensation undergo interruption in the interior
coUiculus? It would seem to me probable, in analogy with the
general sensory conduction path and with the conduction path
for visual impulses, that the coUiculus inferior is not a way
statioji in the shortcut auditory conduction path to the cortex.
It would -uem much more likely that, for the auditory coiuluc-
tion path, the corpus geniculatum mediak- supplies the inter-
ruption, thus corresponding to the ventro-lateral group of nuclei
of the thalamus for the general sensory conduction path, and
to the corpus geniculatum laterale for the visual conduction
{)atii.
The best description of the l)ra(Oiium ([uadrigeminum in-
ferius, since the articles of Meynert and Forel, is that of von
Monakow.* The origin and termination were not at all clear
to the older writers. Kven Forel was satisfied with saying that
it went, along with the lemniscus, into the region of the teg-
mentum, while Meynert put forward the hypothesis that from
t he tegmental region there pass projection fibres to the cerebral
cortex. Von Monakow finds only the indirect form of atrophy in
the brachium (|uadrigeminum inferius after experimental lesion
of the cerebral hemisi)lii're in the dog and after defect in the
region of the operculum and of the temporal lobe in man (his
cases "\Vidmer"and "Seeger"). lie believes, therefore, that
the fibres of the arm of the inferior coUiculus do not extend
directly to the cerebral cortex, but are interrupte(l in the dien-
cephalon (Fig. 55!l). In all probability this interruption occurs
in the corpus geniculatum mediale.
♦ von IMonakow, C. Experinientclli' mid piithiilourispli-iiiiatomisclie Un-
torsncliungcn iiher die Hduhciirprrioii, dpii Seldiiigel uiid die Hi>iri(i sul)th!i-
liiniica iiel)st Ui'itnijjcii ziir K'eiiiitniss friili crwoi'licntT Gross- uml Kloin-
hirndefecte. Arch. f. Psychiat., Herl.. Hd. xxvii (IHiC)). S. 454.
m
vi r-
hr
m)*"
3
llf 4i ' i^T S
874
THE XEItVOUS SYSTEM.
s
'illi
l«) -: t C • ,
y. = - Z.
r' 2 '^ — 3
1-^ ^ -^ IX. 3
i^in'^
V-Ii-^I
i" .^2 5
^ B. - "^ "^
q^' i „' 3 5
s^jH
Ciirpun ijeniculatum
— ^ '"" "^
lutefdle.
N -
c z
= r-n
F2 i
l.iiiitiisfii
Dviiineriit:
jiart of
Substantiii
Jiriichiniii
junrtU'ii
Miiliitl (ire
()/ Ixtnin pv
(hiiivnli.
Fn.i.'isriilfife
ijenerated)
y?-i
1
Fus.'<KrhU' i/e
>'■'.. ^
[iiiiniiiil).
c = - J^
c*- s.Ei
l^Hhstiint
»■ ; r
iiiijra.
lA'inniKCXi
c' ."^
medial i.i
ou
III
liii.si.<i iicduii
^ — z"
li'l III ill till !■
>S. = 2.
ijf'iiirulii'
ulis.
1 ■"* _ ■? Triictii
rZ — ^ — "!
^ = * _^ Xiicliii.i I'cii
c S. ^:^ lull is ijfii '
P S' ;? ^ 11 alts.
g :=. -^ i.
c - = -
Corinm iii-iiiriilii-
tniii iiii'diiilr i(/c-
iji lie I It till).
liiiicliiuiii iiiiiiilri-
ijr III ill Hill ill /I'l'lUs.
Hiuliittiii i-fii'/ioi'i.'<
llfllicillllli llllllill-
liaiiliijeiiiiiiltil).
\ Leiinii.icii,i miinrinr.
yufinntidieticuliii in
lV>4 — Fnsciiiiliis loiijiitmli
'^ I iiiilin iiiiiliuliK.
'T Aqiieili rtus ciiehri.
~ Siicli'ii) nerri ocuhi-
iiiiitiiiii.
('iilliriihis niiiii-riiir.
Rilili.r iirrri diiiIo-
iiiiitiirii.
Iiiiliii llllllill iiiiiiii'
III ,SI(;IC|-(I(,S.
riirliiiiin iiiiiiilii
I'liiiiiiiiii iiifvriiis.
Ciirpiis iji'iiiriiln
tiiin iiiediaU-.
I'tdriiuir.
Ill
iijii
l/llS SUjIffll'l'-
(JROrPING AND CHAIXINCi T()(iKTIIKll OF XKUHOXKS. s75
The topogra{)l)iciil rt'lutioius of the corpus j,M"iiiculiitiiiii iiic-
diiiU' iind its geiuTiil liistologicul cliiiriictoristu's have iilroady been
(It'scribed {vide nupra). Wlion the hiteral k'lnniscus has boi'ii
cut, degenerated tiltres can be traced all tlie way to the medial
geniculate body, but the cells of the nu'dial geniculate bodv do
not atrophy or disapi)ear. On removal of the temi)oral lobe of
the cerebral cortex, however, or on section of the white fibres
passing from the region of the medial geniculate body to the
internal capsule, the corpus geniculatum mediale degenerates ///
/(ifo (von Monakow).* Nissl subdivides the corpus geniculatum
nicdiale in the rabbit into an anterior nucleus, a ])osterior
nucleus containing large cells, a ventral nucleus closely crowded
with cells, a dorsal nucleus, a medial nucleus, and a posterior
nucleus. Unfortunately, thus far these nuclei have not been
thoroughly studied by (iolgi's method. It seems almost cer-
tain, however, from the researches of von Monakow, that a large
])ortion, at any rate, of the axones arising in the medial genicu-
late body run thr(»ugh the retro-lentiform portion of the internal
capsule to terminate in the cortex of the gyrus temporalis supe-
rior, to end, he believes, by free terminal ramifications in the
deep layer of the cortex. Von Monakow holds that (iolgi cells
of Type II (dendraxones) are interposed in the medial geniculate
body between the terminals of the auditory conduction fibres
coming from below and the neurones which send their axones
out to the cerebral cortex. The bundle of white fibres issuing
from the medial geniculate body (Sfiel dcs mediali'ii Knic-
hikkern of the (iermans) to enter the internal capsule occupies
in tlie retro-lentiform portion of the capsule the region just
anterior to and a little lateral from the fibres of the occi})ito-
thalamic radiation. It and the brachiixm quadrigeminum infe-
rius are easily demonstrable in sagittal sections of the develop-
ing brain, now being studied by Miss Gertrude Stein (Fig. 500).
The path followed l\y the auditory conduction fibres is beau-
tifully demonstrable in the cerebral hemisphere by the method
of Flechsig in the brain of the babe shortly after birth, although
the following of the conduction path out to the auditory sense
area in the cortex is rendered somewhat difticult by the fact
that the fibres of tliis path do not run in one plane in the
corona radiata, but make nuiny curves owing to their relation
* von Monakow. Op. cil.
lit
If • '
1 '
^
■i»'i!
S7f
(«»
TlIK NKRV'ors SYSTKM.
to the foasu Sylvii. 'IMic iixoncH of the cells of the incdiiil
{,'eiu('ulate hodv l)ec'ome meduihited Inter tlmii those from the
Fig. 5111)
. 5lil).— SiiKittal scclion nf Imlic's l>riiiii sliorlly iil'tcr liirlli (si'ctiiiii 7(>). .1./.,
iinsa Iciiticiilaris; t'.i., cuiiMila iiittiiia ; /■'./*»/■. rasciciili crrilncpsiiiiiak's
I Ityraiiiidalcsi ; /,.»i.. Ii'imiisciis nicdialis tciniiiiatiiij,' in viiilral iMirtioii of
tlialaiinis: 77/., tlialaiiiiis : T.n.. iiactu.-* i.idicii.-^ : /, .sulistaulia luar.i \ .',
nnclciis liypiillialaiiiiciis ciprpiis Liiy.si » : .;. c-iihr ninlinii ol' l.iiy.s ; ;, mu'lciis
aiciialiis (xfhuleufoimiiji'i- Ki'ivjnr oC Klcclisi;,' and vim 'rscliiscii) : .■;. iiurlcii.s
Iciitiriirinis; '-', corpus K<'iiiiiilaluiii iiicdialc and hcncatli it the tilin's cd' (Ik-
l)i-!i(.-liiuii) (|iui(lriK('ininiiiii iiil'criiis.
lateral genicmlate body, but earlier, aecordiiig to Klechsig, than
any of the other fibres of the region in \\\\n-\\ they are situated.
Flechsig* has been able to follow the ])ath satisfaotorily by
means of horizontal and sagittal serial sections. He says : " The
fil)re bundles of the brachium (juadrigeniinuni inferius, in whieh
are represented without doubt the continuations of the cochlear
nerves, partly become lost in the medial geniculate body where
the fibres l)reak up, ])artly go past this, but close by it. With
the latter are associated the fibres which arise in the medial
geniculate body, and the two sets of fibres go together behind
and beneath the thalamus to the internal capsule, pass trans-
versely through the same, and then go in two separate bundles
to the transverse gyri of the temporal lobe. The one bundle
ascends near the external capsule and arrives from behind and
above into the auditory sense area. The second runs for some
distance along with the occipito-thalamic radiations and ascends,
* Flechsig, P. Gehirn und Seele, ii. Ausgabe, Leipzig (1896), Aiun. 20,
S. 74.
m
Hulcuii centraU* lioUindi.
(il/niH crntnllia iiusltrttir. .^_ ^ ■' '
if^, tlliUl
situiited.
orily by
s : " Thf
in wliich
coclilciir
\y where
With
medial
r l)ehiii(l
ss trans-
Imiulles
l)ini(lle
lind aiul
Ifor some
ascends,
Aum. 2!l,
Hi/rii'i <i ntidliH iinliriiii. ,,^ *
<;i/r<i'i finntiilis infi'i'iiir. /
{•'imntt ri'ivhri liitiviitis iSiilrii)
•^
<j^
(turun occini'
talis 11.
"*% ^yf'in tfiiiiioriilix trnnn-
N rriHiiii (interior.
VUi. .')(!!. —S;ii,'it till scctinii tlimil^'ll tile liniiii of ;i liillic lit tile end of tlic second
inniitli !>!' lite. The lUidilnry sense nasi of the lortex extends ii> I'iir us x.
(After I'. KlechsiK, (ieliiin niid -^. eh', II. And., Leipz., isilti. Till', iii. Fig. 5.)
Fl(i. M\>. — Froiitiil seetiiin thmimh tlie eenliriil heniisidieres of ii ( hild four
niontlis iind ii liiilf ohl. \Vei;;eit prepiiriilion liy \V. Ueiniers. i.\ftei\V. von
Heehterew, Die Leitnn;;sliiiiinen ini (iehirii nnd Kiiekeiiniiirk. Dentseli von
K. WeinlxT};, II. .\ntl.. Leipz.. isil!), S. .lill, Fit;. 5(i:{. ) c.Ihi, hippo<iiinpiis
(eornu iiinnionis) ; re, nnch'iis cnndiitiis; ci, eiipsniii inteniii : erf. eins for-
nii'is; cc, eiipsiihi exteniii; fu. f<irnix; J'li. pednnenhis thiUiinii inferior; ft.
ili'olistic Jiiitli to tile cortex enterin;; into tlie K.vi''"' teniponilis sniierior ; ftii,
C'oroiiii riidiiitii tliiiliiini ' purs (Kirietiilisi ; /;//;. fasciciilns fiyri forni<iiti ; /■«•,
fiiscicnlnssiihciiilosiis : ;;/). kIi'1>"'' piillidiis ; i. insiihi ; iidiit. nuch'nsiiniy};diila> ;
ot. l)iindl<' of til)res from liippociiinpns to tliiiliinnis ; /). tiiscicnli cereliro-spiiiiiles
(pyr.iniidiile.s' ; pt, puUiinen ; th. lliiihiinus ; tru. tructns opticns.
\
i
\'
..>'! Ij li
Si
lw
tf*'
878
b'
u
_ ^
FiCJ. 563.— Nerve cells
in tlic cortex ol' the
jjyriis teniiHinilis su-
perior. (.\fter ('.
Hiiiiiiiiiirherfj, Stii-
(lier lifver Idiotens
kliiiik ocli I'atoloj;!.
- etc.. Fpsiila, 1893,
Tuf. ii, Fig. 2. )
TIIK NKUVOUS SYSTKM.
piiH.sinfj uround tho foHWi Sylvii from boliind
and liolow into the toiiiponil lohc it.><clf,
flosc l)y the second iind tliird teniponil ;ryri,
to roach tlu- transverse temporal gyri " (Figs.
5«il and 5(i5i).
The exact extent of tln^ region in tlio
cerebral <'orte.\ in which the auditory fihrcs
terminate is not precisely setth'd, l)iit, accord-
ing to Fleehsig, corresponds to the two
transverse gyri of the temporal lohe (particu-
larly the anterior), and that portion of the
gyrus temporalis superior immediately ad-
jacent, namely, the third and fourth liftli
reckoned from its anterior extremity.
The cortex of the auditory sense area has
a special structure in tlial the nund)er of
layers is here larger than in any other part
of the cortex except in the visual sense area
(Flechsig).* Six layers are to be made out,
among them some so rich in meduUated hori-
zontal fibres that, at least in many brains,
the auditory sense area can be said to pos-
sess a V'icq d'Azyr stripe similar to that of
the visual sense area. Certain peculiar cell
forms with cylindrically shaped bodies and
numerous large ])yraniidal cells have ])een
described, (iiant pyramidal cells seem to be
absent. I know of no illustration exactly
corresponding to the auditory sense area,
but the accompanying picture, taken from
llammarberg, shows the structure of the cor-
tex in the gyrus temporalis superior, very
close to the auditory sense area (Fig. 6(il5).
In this region, according to Flechsig, be-
gins the temporal cerebro-corticopontal path
(cf. Chapter LXTV). In addition to the
centripetal and centrifugal projection neu-
rones associated with the auditory sense area
there are present in it a number of associa-
* Flechsig, P. Gehirn uiid Scele, Leipzig (1H9C),
S. 75.
UKOUriNG AND C'lIAININd TOUHTIIKIl OF N'KrUONKS. .s7l>
Cyrus frontulu ,.
inftrwr \
Armrti/ien
ilrtt /irr- WrituutM'nmt^
Optreuliun
I'apsula intima
(pan OvnIaUA
tmijUiidiiuitia /«/.
iioJio McipilcthuUutuca
Ura/iit/i-ti
Fisaura colUiitmUa
Purt Alv.
^ftcmura ca/rarifui
Fig. 5B4.— Hori/.Diitjil soctinn tlinniKli l>riiiii sliowiiin tlic rcliitioiis of tlif audi-
tory sL'iisr area to tlio other spui'ch cuutres. ( Vou MoiiakowJ
It- /;
■ ■ 'la
r
! S t
!^^
t i
I*
'1
\m
sso
TIIK XEItVors SYSTKM.
tion ntMiroiics, some with sliort axoiios, <;<>in<; to rcfjioiis of the
cortex iiiiMit'diatcly adjacoiit, otlicrs with h)iijr ax«!ie.s coiiiU'Ct-
O.c.a
Fl<i. 5(15. — Scliciiic of iii'iiniii s siiiM'riiiii><>s('tl to furin tlif iiiiililipiy ciindiirtiiiii
pMtli. Li'it' "ii „■ the siiiiif as ill Platf 11. Fij,'. 1, :il iiid ni' \(p|mii<'.
iiig the acoustic sense Jireu with more distant rej^ioiis of the same
lu'iiiisphere and (throuijh the I'orpus caUosiini) witli the oppo-
site hemisplicre. Of these h)n;; association libres, one bundle.
pe^
aUOUPIX(J AND CIIAINING TOOETIIHH OF XKrUONHS. SSI
(.f the
um'Ct-
N.<lo»o
^
iiiiiluc'tiiiii
lie.
ho same
lltumUo,
the so-fiilk'il rasciculus h)iigitii»liii;ilis inferior, is stated to cdi
neet the uiulitory sense urea with the occipital lobe of the same
side, wliile a portion of the fasciculus arcuatus (fasciculus lonjifi-
tudinalis superior) connects it with the island and with the
gyrus frontalis inferior. In these huiuUes of association lil)res
are axones runnin<^ in l)oth directions. In the auditory sense
area in all prol)al)ility terminate the axones from niunerous
association neurones, the cell bodies of which arc situated in
various portions of the ccrel)ral cortex, but a vast deal of re-
search will be re(piired before very delinite statements concern-
iijs' these can be nuide.
G.cp
Cauda
nucl.caud
•"'"■P" Fisi.calc.
Fid. r>«().
Cuneus
-ScIk'iiu' of iicuvdiics iirauilitciry coiicliictiim \yM\\. l.vUrriwa the siiiuo
as ill Plate 1, I'jl'. 15.
The IV 'itory sense area on the left side has been proved to
be of especial imjtortance in connei'tion witli the fuiu'tions of
speech. It is, in fact, identical with the "centre for the
sounds of words " which are so necessary for the develoi)nu'nt
of the so-called " internal speech." Lesi if this rej^ion on
the left side leads to " word dciifness." '^i .entre is related
to the other speech ci'utres by means oi association liitres.
Present ideas concerning these relations are schematically repre-
sented in t^'e diagram taken from von Monakow (Fig. A»'>4).
«
I ,
p
I '
882
THE NERVOUS SYSTEM.
A lesion of the auditory sense area, on one side only, does not
destroy hearing in the opposite ear, but probably interferes to
a certain extent with the hearing of both sides. Bilateral lesion,
involving the auditory sense area on the two sides, causes total
deafness. It is not surprising that unilateral lesion does not
cause complete deafness, since, as we have seen, there are mani-
fold decussations of the auditory fibres in the lower portions of
the central nervous system. Thus there is partial decussation
in the corpus trapezoideum, and again in the mesencejjhalon,
especially between the two inferior colliculi of the corpora
quadrigemina. A further commissure in the auditory path to
which little attention has been paid is to be found in the com-
missura inferior (auldeni. All the evidence goes to show that
this commissure connects the medial geniculate bodies of the two
sides, and, as we have seen, the medial geniculate body on each
side represents a most important way station in the conduction
path from the internal ear to the cerebral cortex. I should not
be surprised, therefore, if the commissura inferior (iuddeni were
of the iiighest significance as an auditory commissure.
In the diagrams, Figs. 5(i5 and oC)*), the principal groups
of neurones in the auditory conduction path are schenuiiically
represented.
li
III!
SUBSECTION III.
Neurones Connecting the Central Nervous System
with the Voluntary Muscles of the Body. (Lower
Motor Neurones, or Peripheral Centrifugal Neu-
rones.)
CIIAPTKR LV.
THE LOWKU MOTOR XKUKOXES.
Generiil di'seription — Tlioso pertaiiiiiij^ to the spinal cord — Perikaryons of
the ventral horn — 'Vlw " middle cells " — The ventral roots of the sjjinal
nerves — Motor nerve-endinj^s in muscle — I'hysioloj^ical studies — [jocali-
zation of motor function in the segments of the spinal cord — Starr's
talile — Researches of Sano, Hernheimer, and Schwabc — Columna me-
dialis — Columna intei'medio-lateralis — Columna extrcmitiitis superioris
— Columna extremitatis inferioris.
TnK neurones next to be considered are those which bring the
vohintiiry muscles of the body under the iulUieiice of tlie nerve
centres. Between the nerve centres and the vohmtary nuiscles
one set of neurones — the lower motor neurones — exist, just as we
have seen that for the connection between peripheral sensory sur-
faces and the nerve centres one set of neurones suflfice.
The cell bodies and dendrites of the lower motor neurones
are all situated within the central nervous system, so that the dis-
tance between the central nervous system and the voluntary mus-
cles is traversed by the medullated axones of these neurones.
Those axones make their r-xit from the nerve centres always (with
the exception of those of the iiervus trochlearis, ride infra)
from the ventral or lateral surface of the cerebro-spinal axis. The
bundles of medullated axones make up the ventral roots of the
spinal nerves and the motor portions of the cerebral nerves.
Th', lower motor neurones are situated in the parts of the
cerebro-spinal axis below the diencephalou — that is, in the meseu-
i! !
«S4
THE NKRVOUS SYSTEM.
Id:
i, I
cepliiilou, rhoniboncephiiloii, and nuHlulla spinalis. The cell
bodies and dendrites of these neurones occupy a very definite
position in the cerebro-spinal axis, being situated always ventral
to the central canal, occupying in the medulla spinalis certain
portions of the ventral and lateral horns of the gray matter, and
in the rhombencephalon and mesencephalon regions which cor-
respond to those mentioned for the cord.
It will be convenient to describe first the lower motor neu-
rones incident to the medulla spinalis and afterward those be-
longing to the rhombencephalon and mesencephalon.
(A) Those Pertaining to the Spinal Cord.
In the spinal cord the cell bodies, it has generally been
taught, are arranged in the ventral and lateral columns of gray
matter more or less segmentally * — that is to say, longitudiiud sec-
tions through the cord show that the cells are not evenly distrib-
uted, but arranged more or less definitely into groups (Schiefler-
decker,f Schwalbe, J and others). The literature of the subject
has been collected and analyzed by Li'ideritz. ** The total num-
ber of motor cells varies much in different portions of the cord.
Tlu'y are most numerous in the cervical and lumbar enlarge-
ments, corresponding to the innervation of the muscles of the
extremities, least numerous in the thoracic cord whence the com-
paratively small bulk of trunk muscles receives its nerve supply.
In addition to the longitudinal grouping, in cross section also the
cells show an arrangement in di'finite grou})s, as (Jerlach first
pointed out {vide infra). Waldeyer,|| in his elaborate study of
the spinal cord of the gorilla, divided the ventral horn cells into
a medial ventral and a lateral dorsal group, a classification agreed
to by Kaiser ^ in his very thorough study of the cervical cord.
* It is to ho noted that inic truo ('i!ihryoloj;i(.'jil iiciiroiiicrc |)n>liiil)Iy cor-
respoiids to several of the seffiiii'iUs or segmental groups of nerve cells whieh
the histohigists liave deseriljed.
+ Sc'liieffenU'ckor. I*, neitiiige zur Kcnntniss des Faserverlaufs in Klick-
fiiinark. Arch. f. inikr. Annt.. Hoiin. lid. x (1874). S. 4Tl-4i)4.
X Seliwalbe. (i. Lclirl)iieli der Xeuroloj^ie, Hvo. Erlangen (IHSl). S. ;584.
* liiidoritz, V. Teher das Hiickenniaiksegnieiit. .Vrcli. f. Anut. ii.
Physiol.. Anat. Ahth.. Leijiz. (IHHl).
I Waldeyer. W. Das Gorilla-Uiickonniark. At.haiidl. d. kgl. Akad. d.
Wissensch. zn Merlin, aus dem .Tahre ISSH. Herl. (1SH9). S. 91.
■^ Kaiser. O. Die l-'unktionen dcr (lan,i,'li('nzellen des Ilalsniarkes. Ge-
kronte Preisschrift, Haa^', Mart. Nijholl (1891), p. 71.
m
1^!
(JHOl'lMNU AND CHAINING TOUKTHEH OF NKL'KONES, ,ssr>
Tlio arnmgotiicnt of tho motor cell jrrnups in Ininiivn beings
liiis been fare fully studied by von Lenliossek in the cord of a
healthy young man.* Inasmuch as the application of (Jolgi's
method has convinced von lienhossek that the cells situated most
nifidially and ventrally in the ventral horns send all their
axones not into the ventral roots of the spinal nerves, but
through the ventral commissure to the other side of the cord,
this investigator excludes these from the motor cell grou})s, desig-
nating them the commissural group (Fig. o(iT). \ In the ventral
horn, as far as the third cervical nerve, von Lenhossek makes
out only a single small longitudinal, rather narrow group of
ventral horn cells, separated from the group of commissural cells
by a narrow space free from nerve cells. From the fourth cer-
vical uerve to the beginning of the cervical eidargement this in-
terspace becomes much broader, and, in addition, the motor-cell
group becomes divided into two well-separated cell nests — a
vencral group more medially placed, and a liorsal group more
laterally placed. The interspace between these groups is charac-
terized not only by the aijsence of motor cells, but also by the
presence of large numbers of (ine nerve fibres which run in be-
tween the groui)s.
In the region of the cervical enlargement (from the level of
the fourth to that of the seventh cervical nerve) von Lenhossek
finds a progressive though gradual increase in the number of nerve
cells in both motor groups, so that the motor area here is rela-
tively large. The increase takes place, however, mainly in the
dorso-lateral group, which now exceeds very markedly in size the
ventro-medial group. In places the dorso-lateral group shows a
division into two compartments. At this level the medial grou))
is se]iarated from the group of commissural cells by a broad tieUI,
which corresponds to a ilistinct indentation in the ventral mar-
gin of the ventral horn. A similar indentation of this margin
* von Lenhossi'k. Op. cil.. S. ;V*1.
+ This is the trnnip uf cells which in the tiil)liofrr!ipliy i^ fre(|iictitl.v ro-
ferri'il to as the " tnc<tial anterior frroiip of anterior honi cells." They have
been so deserihed liy Kaiser as an uninterrupted colunni n^ulin^' almost the
whole ieiislh of the cord, siipplyiiit;, he lielieved. the Iumj; muscles of the
hack. Aeeonlinp to von Lenhossek. their axones are in pari short, tenni-
iiatiuf,' in the fjray mailer of the opposite ventral horn, in part lonu'T. run-
ning,' out into the white mailer of the opposite side of the curd— hele-
romerie neurones in the sense of van Clehuchten.
880
THE NKRVOrs SYSTEM.
rii'
V :
III!
exists between tlie dorso-lateral and ventro-niodial grouj) of
motor cells. The size of the ventral horns rapidly diminishes
between the level of the eighth cervical and that of the first tho-
racic nerve, and the relations in the lower part of this region cor-
6.1.
\
A I^Wi = Hi>(l.
c aamum = Violet.
D iiiiiiiiiiiiiigig — Hill'".
E .. = Hrown.
"^ J = (irecn.
Fig. 306. -Sclu'iiieof the strufturc of tlicspiiuil cord; nerve cells shown in tlio
left half of the cord : colliitenils shown in the rijiht half of the cord, i After
.M. von Leiihossck. l)er feiiiere Ban des Nervciisystenis. etc., 2. Anfl., Herl.,
IHil."), Taf. vi. I LeII half of the cord, hhick cells are motor; side lilnils are
seen arisinj; from their axo\ies: red cells are t;iulomeiic neurones, theaxones
fjoin;; to the ventral and lateral fiinicnli. Amonj; these arc the cells in the
nuclens dorsalis and s<pme <<lls in the snhstantia ^elatiiiosa of Rolando;
collaterals are cominf; oil' from I he ax<iiics. N'iolet cellsare commissliial cells
or heteromeric neurones; one is seen sendiiif; its axoiie into the ;;ray slih-
Stance of the other side ; the othi'rs send their axoncs into the white matter
of the o]i|)osite side. The frreen cells send their axoncs to the dorsal funiculi.
In liluc is .seen represented a (iol^i cell of 'I'.vpe II, or dendraxone. In tl"
rinht half ol' the ccu'd the hlack <-ells reprcseul Ihc cell hodics of peripheral
sensory neurones situated in the }.'anf,dion spiiiale; their centr.il prolontxa-
tionsare shown enlcrini; the s]iinal coiil as (hu'sal-root lllires, which hifurcate
and send collaterals |o terminate in various parts of the suhstautia Krisca.
Thus the rclh \ collaterals are seen troiny to the ventral hoiii ; other col-
laterals enter the nucleus ihirsalis; some liass thr<pu^'h the dorsal couiuiissure
to the dorsal horn of the opposite side. The red collalerals come from the
white llhres in the ventral and lateral fnni<idi ; the lilac collaterals hcloun
to the axoncs of heteromeric miirones; the hrowii collaterals and terminals
rejircsent lihres from the fasciculi cerehrospinales oi- pyramidal tract. /,
fasciculus cerehrospinalis \entralis; .'. fasciculus ventialis proprins;,;, fascic-
ulus ventrolateralis (iowersi ; .(. fascieulus cerehellospinalis ; .'), fasciculus
<'erehrospinulis lateralis;'.'. fasci<nlns lateralis proprius; ,\ funiculus dors;iIis ;
li.v., radix veiititilis ; R.d., radix dorsalis; U.S., ganglion spinale.
li
(JUoriMNO AND ClIAIN'IXCi T()(!HTIIEI{ OF NKUKoNKS.
SH7
v-
)\vi\ in tlio
. lAfllT
nil.. H«m1.,
lihrils inv
(■ iixoiit'S
Is iM tlic
IvoImiiiIc) ;
lUral tells
yi-iiy siih-
iii;itt( r
fimiciili.
In tl"
iiriiilnial
pniloiitjii-
hil'iiniiti'
i:i Kriscii.
itllfV «'"1-
iiiinissmi'
rum till'
s licloiiK
tcnninals
tract. /.
; ,i, lasric-
I'asciculiis
s (l()i>>alis :
rosjinnd to thoscMlcsoribcd by voii Loiili()sst''k in the upper part of
tlio cervical reiiiou — tiiat is, tlio motor cells are represented by a
small siiiji^le longitiuliiial mass, separated from the commissural
cells by a narrow stripe free from nerve cells. In the upjujr two
thirds of the thoracic cord the group of motor cells is no longer
separated from that of the commissural colls ; both sets of cells
are reduced in lunnbers, and the two together make up the nar-
row longitudimd column of nerve cells in the small thoracic ven-
tral horn, the medial cells being commissural, the more lateral
ones motor root cells.
From the level of the ninth thoracic nerve on, von Lenhossek
describes again a progressive change in the appearances. 'I"he
motor cells become gradually sej)arated from the commissural
cells, so that beginning from the level of the first lumbar nerve
there is seen a very broad interspace between the two groups of
cells, broader indeed than in any other region of the spinal cord.
The motor cells increase here enormously in nu miters, until the
level of the first sacral segment has been reached, where tlie
motor cells are so numerous as to cause the ventral horn to pro-
ject as a broad, ]dump hemisphere. Very soon within the motor
group two subdivisions, as in the cervical cord, can be made out
— a ventro-medial and a dorso-lateral group. In addition, from
the level of the fourth lumbar segment on, a third, or central
cell group, corresponding about to the nuddle ])oint of the ventral
horn, is distinguishable. This group is most distiiu't at the level
of the first and second sacral segments. Jjower down the charac-
teristic grouping gradually vanishes, the first to disappear being
the central group. Soon a division into ilorso-lateral and ventro-
medial ceases to be visible, and again the motor cells become
united into a single cell column which gradually diminishes in
extent. The reduction, however, does not express itself, von
r.enhossek states, as in the thoracic cord, by thinning and sharp-
ening of the whole ventral horn, but the ventral horn remains
jdump as far as its lower extremity, the cells gradually becoming
less numerous.*
* (iolgi 1ms (ihviiys eoinhutcil tin- view nf a (Icriiiitc localization of tho
motor cells in firoups in flic ur.'iy matter. I ijuotc from liis Snlli' fina anii-
tomia tlct,'li or^rani ccntrali del syslenia nervoso, F.ililorc l'. IIoc|ili, Mil.iiio,
1885. p. 'MIJ: ''As re^janis the disirilmtion of the motoi' cells in the jrray
substance of the spinal conl. I must here reniarU that it is a mistake to try
to establish the seat of these as the chief ttiaracleristic lor a judgment re-
68
iv/-',??*-. "]
888
Tin-: N Minors system.
Im
M§
if
Arjjiitiiisky * liiis rccciitlv taken iijt the siil»j('<'t in Waldcycr's
laboriitory. He cuiu'IikIcs tliat in tlio colunins of motor cells and
in the nucleus dorsalis there is no distinct nieinberment of any
sort. l*"or the " middle cells" {MiUflzvIb'usiuihn) and tiie cells
of tiio hiteral horns he iinds an extraordinarily sharp separation
into fjroiips (I''ii(. r)(!S), l)iit emphasizes the fact that thus far no
one has jiroved the existence of a true sejiiueiital arranjfcmeut of
the cells in any of tlie gray columns of the cord.
The cell bodies of the largest motor cells form the most prom-
inent elements in the spinal cord. There are among the motor
cells, however, smaller forms the axones of which undoubtedly
enter into the formation of the ventral roots of the spinal nerves.
The differences in calibre of the ventral root iibres have long
been recognized, 'i'he coarser fibres are medullated earlier than
are the finer (von Hechterew). According to (Jaskell ami Mott,
the coarse Iibres are destined for the voluntary muscles, the li!ie
fibres for involuntary muscles, by way of the sympathetic system.
The structure of the axone hillock is shown in I"'ig. 7ui).
The internal structure of the motor ventral horn cells has
been already described (Section III). It will be recalled that
they are typical multipolar stichochronie cells in the sense of
Nissl (Fig. r)(Iii). The dendrites arising from all parts of the
panling their fiuictioii. The ('cIls situated in tlii' ventral colunins are. it is
true, iiredoniinantly nicitor in nature, beciiuse the {greatest nuinlier of these
send their funclional |irncess into the ventral rents. However, just as one
can not say. without reservation, that all the cells of the ventral columns
enter into relation with the correspond inj; nerve roots, so it is also not true
that it is not exclusively the cells which lielong more or less strictly to the
ventral horns which hecoine connected with the ventral roots.
'• I am certain that the cells which send their axis-cylinder ]irocosses out
into the (motor) ventral roots can l)e met with in every pari of the gray sul)-
stance: (l)in the ventral horns where they are certainly predomiiuiiit ; ('i>
in the /one of gr;;y sulislance which 1 have named the •intermediate zone,'
and which, lying in the region limited tiy the lateral columns of white nuit-
ter and the centr.-il canal, forms a zone intermediate tu't ween the ventral
columnsand the dorsiil columns of the cord; (It) in the dorsal horns with
the exception of the ih.rsal border— that is. the border which forms the so-
called gelatinous substance of Holanilo. In this latter, up to the present
time, only cells have been found the axones of which branch in an extremely
comi)licated way."
* Argutinsky. I*. Uebcr cine rcgelmilssige Gliederung in der grauen Suh-
stanz des RuckeiMiiMrks bcim Xeugcliorenen und fiber die Mittelzelien.
Arch. f. niikr. Anat., Honn, Ud. xlviii (IHUT). S. 4!»C-5:2:J.
fJKOriMNCJ AM) CIlAlXIXCi TOGETIIKR OF NKURONKS. SS9
cell spread out into various regions of the cord, so that the possi-
bilities of contact relation are very great, h'urnnii y Cajal divides
;A5'f .*- ^•- ^'. • -v
•//< ^.
-'^■«-Wj
7/.r7>.
.(/.f-7..
h-fc-i "■.■-*> !■»**
//C6. ; v^-^
j.>'..-..,.'r.'?-.j4f......
.' . * • • •
o ^
• 1*^
//.r7).-
ro; .
H.c.b. j5t.-,....J..;.p „ .
:.t:«
<<7 •
ts»
■f/.c7A
■//.c./;.
• :<W- ^'•
FlO. 508. — (Jniups <il' middle cells in ii fmiital li)iiKitudinal si'ctioii tlirmifili the
tiionieie spinal curd of iiewlMini liabe. i After I'. Arjjutinsky. Arcli. I', nnkr.
Anat., Honn, Hd. \lviii, ls<i7, 'Paf. xxii. Fig. 'i. xx. I'linieiilns lateralis ; H.c.b. t
horizontal eereliellar hniidles ol' I'lechsin.
800
TIIK NERVOUS SYSTKM.
the deiulritos into three sets: (1) a niediul group which ])a.sses
toward the ventral cuiniiiissure in some animals deciissaliii;Lf with
those of till' ojjposite side, so as to give rise to a di-liniti' " proto-
j)lasmic commissure" (Fig. •"ill) ; ('v) a ilorsal set running toward
the dorsal horn ; (3) a lateral set running out toward and into
the lateral funiculus, in some animals reaching the surface of
llil>!fii||
'ti
k ■T
Fi(i. 5t)9.— Motor nerve cell from veutrul liorii of Kiay matter of spinal eonl of
riil>l>it. (After Nissl. ) Of tiie three lower in'oeesses, tlie middle one repre-
sents tlie axone. All the other pi-oeesses are dendrites. Tlie marKilis of tin'
cells and of the masses of stainalile snhstanee appear too sliarji in the repro
(hictioli. At the ansleof the di vision of the hirjie dendrite at the left snperior
imKle of the (•■11 is shown one of the "wedges of division" ( ]'rr-irfi(iiiiiiis
lr<irhi>. The s])indle-shapid Nissl bodies are widl shown, esi)ecially in the
dendrites. This cell is classed hy Nissl as il stichochronu' nerve ctdl in the
apyknoinorphons condition.
the cord in large numbers so as to make a sub-i)ial plexus of
dendrites. The large axone arising at the axone hillock plunges
^m
'IlL
oiutri'iNt; AM) ciiAiNiNc T(m;i:thki{ of nki'honpx s\n
usimlly l)y tlio sljortost route, soniotinics, however, liy ii devious
course, into tlie nearest ventral root of a spinal nerve, leavin<»
the spinal cord at the ventro-lateral sulcus, '{'he invelin siicath
Fl(i. "iTO. — Vcntnil lioni rill (Vipin tlw IiiimI):ii' rem! cif ilic iw, >li(p\\ ini; jivcitio
liillnik. Allir llilil, Aich. f. Ariiit. ii. I'liysiipl.. Anal. Alitli.. IMtT, I":!!', ix.
l''iu.lo. ) 'rrcatiiiciit with aiiiiiiciiiiiiiii liiilinniiMli', I to inoi). I'aniHiii Mclimi
l.r> iiiiridiis thiiU. St:iiiiiii« with (r,vllirii>in ami imtli.vlciic liliir. 'i'lic
jjniuiKl sulistaiicc is markedly va»iii>ii/.i(I. Tlic iiciiniMiiiics art- tlctolori/cil.
Fid. T)?!.— Transverse section iif the sjiinal enrd iif Larerta AkIMs. ' After. ■^.
K'anioii y Ca.jal, Lis nniivelles iilees. eir.. A/.Mulay, I'aris. Is!tl. p. -'", i'i;.'. 7. i
. I. eells (if ventral horns, the ilenilrit<'s iif which help to make n|i a vi niral
piotoplasniie I'onniiissiire ; />'. heteromeric neurones; r. tanlomerie and hi<a-
tero'ueric niiiroiies; />, dorsil protopla>mie eominissure; /•.', dendrites of
ventral horn eells extenilin;; far out into white matter and foiniiny a peri-
medullary plexus ( /•' I situated heneatli the pia mater, espeiially over llie
funiculus lateralis, wlii're tluse dendrites come into contact nlatiou with the
collaterals ami possilily of terminals of theaxones of the white matter: (i,
nidix dorsalis ; I!, collateral from dorsal root tilire ; li, a.xones.
w^'w
'/
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TEST TARGET (MT-3)
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w<
892
THE NERVOUS SYSTEM.
IIJ<
does not begin until tlie iixone has passed for a short distance
from the cell. From the non-medullated j)ortion of the axone
there arise constantly in human beings, inconstantly in many
animals, from one to four delicate branches, the "side fibrils "
of (iolgi. These are always non-medullated and run back toward
the cell bodies which give rise to the corresponding axones.
Several have thought that tiiey come into contact with the cell
body just as do the side tibrils from the sjiinal gi:iiglion ce'ls,
which iiuber has described.* Others, however, believe that in
running back they come in contact rather with the terminals of
sensory collaterals of the dorsal root fibres. This view has already
been mentioned in the discussion regarding the possible cellu-
lipetal conduction by the side fibrils (Section V).
The ventral roots of the spinal nerves contain the motor
fibres of the peripheral nerves. They are, in actuality, nothing
more than the medullated axones of the motor cells of the ven-
tral horns. A number of fibres from each ventral root pass by
means of the rami communicantes into the sympathetic trunk. f
In the spinal cord on each side there a;e thirty-one of these ven-
tral motor roots — eight cervical, twelve thoracic, five lumbar, five
sacral, and one coccygeal (Fig. 572). The nerve roots do not
everywhere correspond to the vertebra?. The exact relations of
the various roots to the spinous processes of tlie vertebra? are
clear in the table })repared by Keid.J It would be a mistake to
assume tliat each ventral root corresponds to a definite peripheral
nerve, for this is not the case. It has been proved {vide infra}
IH
* Held (1807) has suggested that these recurrent " autocelhilar " collat-
erals of the lower motor neurones may represent an important mechanism in
connection with the so-called muscle sense.
f The axones of ve'itral horn cells which pass through the rami com-
municantes in order to terminate by free end-arborizations about the cells
of the various sympathetic ganglia are believed to be n<otor and secretory
in their function. The secreting glands and the smooth muscle of the
blood-vessels, and of the viscera generally, are innervated by means of
sympathetic axones. The exact relations here have yet to be determi\ied.
Certain it is that the complicated local mechanisms of which the symjia-
thetic system is the seat are, to some extent at least, brought under the influ-
ence of the neurones of the ccrebrospimd system. The motor nerve-endings
in smooth muscle have l)een carefidly studied l)y Berkley. 'I'he neurones of
the cardiac ganglia of the sympathetic are sut)ordimited to centrifugal im-
pulses from the medidla oblongata.
X .1. Anat. and I'hysiol., vol. xxiii (188!)).
"^;.
GUOUPINO AND CHAINING TOGpyniKR OF NKUUONES. 893
y LI
that each peripheral motor lau've, especial-
ly those going to the extremities, receives
fibrt'S from a whole series of different ven-
tral roots, tiie oi)portiinity for such dis-
tribution being afforded by the different
nerve plexuses (cervical, lumbar, sacral),
and also by the large nerve trunks them-
selves, which, it seems, are to be looked
upon as a kind of nerve plexus. It would
seem unnecessary to repeat here what has
already been discussed at some length in
Chapters XVII and XV III. The remarks
made there with regard to the neurotome
and its relation to the myotome, and the
distribution of the fibres in the mixed
nerve stem formed by the union of the
ventral and dorsal roots, are just as ap-
plicable here as there, and can be referred
to.
The motor axones of the ])eripheral
neurones may divide several times on their
way to the voluntary muscles, so that one
neurone is capable of innervating a con-
jsiderable number of striped muscle fibres.
Arrived at the muscle in which they ter-
minate, the bundle of nerve fibres breaks
up in the perimysium, forming in it a
plexus (Fig. '")T3). The individual nerve
Fl(i. 57:3. — S])iiial imd in (•niincctioii iiIpdvc witli
tlic iiifdiilhi oliloiiKiit;! and |«ins. (After A. liaulicr,
Lchrliucli (lev Anatmnic dcs .Mcnsclicn, V. Au!l..
Li'ip/., isiis, lid. ii. S. odl, I-'ifr. Js.'). ) I', ntivus
trifjcniinus ; A'//, niTviis Ii.vihih:1(issus ; (\. lirst cer-
vical nerve; C'-^, secnnd to lifjlitli cervical nerve:
T l-IJ. first t<i twelftli tliKraeic nerve; /. I-!.',, first
ti) tiftli lunihar nerve: N /-.), lirsi to liftli siicral
nerve: ti, iiervus c(>ccy;;ens ; .r. x. (iliiin terniinale of
tile spinal cord. frmn t!ie rcmt marked /.| tii .r,
caiula e(|uina ; li'r. pU'.xus liracliialis ; Cr. nerviis
feinoi-alis ; .S', nervns iscliiadicus ; O, nerviis ulitnra-
torius; the enlarKenient oppositi' /.. .;. (. and .■; repre-
sent the spinal Kantjlia on ihiMlnrsal nmls. On the
left side iit'tlie liyur ■ the syiiipnthetic trnnk is shown.
a to .s.s' are KanKJia: <i, «ant;lion ccrvicale supciins;
/> anil c, fiaiiKlion cervicale inedimn it inl'eriiis; i!,
first thoracic KiinKlion ; (/', last thoracic jiMnylion ; I.
lirst hunluir ganglion ; .•<■■«, linst .sacral ganglion.
W'
O-l
%
A2
\Cr
Fio. 573.
I
H'.
m
S04
Till-: \i:i! vol's svsTini.
fibres can divide from one tu tliree times, each time giving rise
to from two to five subdivisions. In tliis wav the nuinbor of
Kl(i. .173. Nerve plexuses and teniiiiisils from vlie imisele (if ii li/ard, after Ireat-
liielit Willi (lihite acelie acid. After 1'. Scliietl'erdeeker, ( iewelielelire,
Bramiscliw., 1S!)1. S. 117. Fijr. !Mi. ) The plexus on the left tjives olf liraiieh-
inn lilires, which i;ii|cithe iiKilor nerve I'ndin^is, indicated liy I lie uucleus-
like aii|i<arances. 'Chi' nuclei (if the muscle lilires anil lliiise nf Schwann's
sliealh have imt lieen drawn, and the cnniieetive tissue :.•, omitted.
nerve fibres is considerably increased, until finally there are a
sutlieient number to supply every muscle fibre with one or sev-
orid nerve-endings (Schielferdecker). The number of nerve-end-
ings for the individual fibres Viiries; thus the fibres of tlie gas-
trocnemius and of the triceps of the frog always receive, according
to Sandmann, one nerve-ending at about the middle of the fibre.*
The libres of the sartorius, on the contrary, each receive troni
two to six nerve-endings. In the rectus abdominis muscle a fibre
(if each muscle segment is said to receive its own sjiecial nerve-
cndiuLr. Willi ' this appears to be true for frogs, in mammals, in
* Sandiniuin. UeliiM' die Vertlieilimsjderinotorisclieu Ncrvenoiulappnrato
ill ilcii i|iieri,'estreifien Muskejn der W'irliellliiere. .\reli. f. .\iiat. u. I'liysidl,,
I'liysiol. Alitli., I.eip/. (ISS.-u. S. '.' |(l-'J."i'^.
(iH()L'I'IN(; AND ('n.\IXI\(i TOCKTIIKH (»F NKllMNKS. >■»;,
B
4,4 .
Jiv
% V
are a
or sev-
rvo-f'iul-
spito of their great length, the iiidividiiul Tiiustli! lil)rc appears
to need only one nerve-ending.
The views concei'iiing the exact mode of nerve-ending varv;
it is generally slated that the nieduUated libre, having arrived at
the muscle in which it is to terminate, sends its axis cylinder
only into the iibre itself, the neurilemma aijpearing to fuse witii
the sarcolemma, the myelin sheath disappeaiing. The continua-
tion of the axone then bratiches manifoldly so as to form telo-
dendrions of various appearance. In rejttiles one sees tyi)ieal
motor end plates so well known since the studies of Kuehne.*
In Fig. oT-t the appearances to be met with in Laccrta are shown.
The appearances are (piite dilTerent in ditfercnt animals. In Fig.
TjIo the relations of the frog are illustrated ; in Mg. ."iin, those in
-"-T-*,!
Fifi. .'■)7J. — Mo'iir tcloclciidiidii : cxaniiiicd iVoli in pliysinldtjiciil suit sdliition
t'nmi LiU'crtii A^'ilis. (Al'tcv \V. Kiiluic Zlsclir. f. liinl.. I!il. xxiii ; taken
frniii Scliicll'cnlccki r's (icwcliilclirc. I Tlic iiLcdnllatcd axmic has lictii torn
(i(V slioit ; tilt' iHltlci iif the >()///('i(x»/).s7(/H~ ari' Will sluiwii. ( hir liiiclciis of
till' iiL'tirilciiiiiia and two nmlci of Hciilc's slicatli aio sliowii on the lurvi'
filire. Tlu' nuclei of the ninsi le tihic are lasily visilile.
the rabbit. In every ease the a.xone breaks up into a nundjcr of
subdivisions, many of which iippetir to sfn'oid out into disklike
platelets. Von Kolliker, Krause, and others do not believe that
the axis cylinder and telodendrions tire situated between the sareo-
^ I
* Kiichiie. W. Xcne I'literstu'huiifjcii iiIkt iiiuiofisciii' Xprvi-neiidi^^'iiug.
Zcitschr. f. IJiologie, IM. xxiii, [ip. 1-14!).
Il i
f J (, 111
►■ '!
I
SJt(]
TIIK NKKVOUS SYSTKM.
l(Mnm!i 1111(1 tlu' iiiiis('l(>, but assert tliiit it lies tijum tlio sanio-
leiiima itscll'; tliat tliis in'iirilciiiiiia accdiiipaiiii'S the subdivi-
^"^CL:.
GA.^.
'-iixS?- -^
^^
=^.--^v.-r-^
l''l(i. 57i
Kii
IS't
nut
.slio
line
I. S.
lull;
Wll.
Motor iitTvc riidinn on tlu" M. {liislrociicmius of llic I'lo^;. < \
, MS iiKiililicil l>.v IV Schicll'i'i-dcckcr in liis (icwclnli'liic, Hniui
. I."C', \'\!i. 100.) 'I'lif iiU(liilliil»Ml iicrvr lililc N. ilividi's iiitii
iti'il tcniiiiiMl UniiK'li
(Uv \\.
iiscliw.,
scviiai
till' crossi'ii striatioii of IIk' iinisrlc is not
(r'.l, iioii-iiirdiillatcil tcnidiiiil lilirils with iidjucciit niit'lci.
sioiis to tlieir toriniiiations, aiul that it is Ileiile's sheath \vlii(!h
unites with the sarcolemma. The majority of investigators,
liowever, ineliuliiifj Kiiehne and SchictTerdeciver, take tlie oj)j)o-
site view. Sihler, of C'levehmd, believes that the nerve fibrils
are situated outside the sareoleninia, and I must say that the
beautiful speeimens j)repared by his method, which throiij^h his
kindness I have had the opportunity of studying, speak strongly
in favor of his view — at any rate, so far as the endings in the
Fig. 571). — N'crvc oiidiii): on an intercostal nillsclc of the raliliit. (iold iircpani-
lion. (.M'icr W. Kiilini-, Ztsclir. f. Hiol., Hd. xxiii ; takt-n .Voin Schiidlcr-
di'C'kiT's (u'Wi'liidchri'. i
frog !ire concerned. Apathy, however, by moans of his gold-
chloride method, demonstrates the e.xistence of a very compli-
cated arrangement of his neuroJibvilUn, inside the individual
^■""■"llff 1» )
(iI{(»LlMN(; AND (;ilAININ(i TOdKTII Kit (»F Ni;i|{( »Ni:s. s".)7
iniisclu cells. His ol)st'rviiti<»iis have hern iilrcady nsfcrriMl to in
Cliaptcr \'I, ami l"'ijf. 'Z] in that diaptiT may a^'aiii lie n't'crnMl
to.
Siiic(! tlin introduction of the vital Htaiiiiii;^ with tncthylctic-
bliic a number of ^^scarcht'8 boariii;^ upon the endings of motor
axoncs in striated voluntary muscle have been forlhcominj;. We
lU't'd otdy mention thost; of I'lhrlich,* hoj^iel,t and especially
Ketzius.J 'l"he investigations of lleizius are of parti(!iilar vahu;,
uince they ineliule objective descriptions of the motor endings in
a long series of vertet)rate (dusses. Tlu! n^cent literatun? has
been collected and briefly epitomizetl by Kalliiis.'* 'i'he whole
lower motor neurone from the nerve centre to the muscle is
echenuitically illustrated in tlu; diagram (l''ig. oTi).
The localization of function in connection with the lower
motor neurones of the spinal cord is a topic which in late years
has interested a progressively increasing numi)erof investigators.
After the pnjofs brought by Sir C>harles li(dl in regard to the
motor natun; of the ventral roots aiul of the sensory nature of
the dorsal roots had been generally recognized, there arose con-
lli(;ting opinions in the earlier part of this century concerning
the functions of the iiulividual spinal nerve roots.
l'anizza,|| as a residt of iiis experiments, de(;ided that section
of one nerve root caused oidy temporary weakness of the limb as
a whole, the weakiu'ss increasing in proportion to the number of
roots divided. Complete paralysis resulted otdy when the last
root had been cut. According to I'anizza, therefore, the various
roots acted as a whole, each one of them being capable of main-
taining the functions in their integrity. .Johannes .Midler and
van Deen decided, from their own experiments and from those of
Kronenberg, that the purpose of the lu'rve plexus, so far as the
* Ehrlitli. P. i'ti)i'r diu Mrthylfint)l(iiireakti()ii dcr lebonden Nerven-
sulistmi/,. Di'iitsclie iiii'd. W'clmsclir., IJcrl., IM. xii (188fi). .S. 40-.")2.
t Dogiol, \. S. M('thyli!nl)luut,iiiktioii dcr motorischt>n Xorvpnotidi-
gufigL'ii in deu Miiskelii der Am|iliihicii uiid H(>[itilit'ii. Arch. f. inikr.
Aiiut., Bonn, Bd. xxxv ilHKO). S. '.H)r,-:V2{).
I lletzius, ('. Zur Komitiiiss dcr molDrischcn Norvenciidifjimgen. Bidl.
UiittTsueh., Sloekhohii. n. F.. Bd. iii (18!)2). S. 41-52.
** Kallius, K. Eniligiiiigcn inotoriscjluT N'tTViiii in dt^r Muskiilatiir der
Wirbehliiere. ."Merkcl-BDii net's Krgi'lm. dcr Anat. n. F^ntwick., Bd. vi for
18!»6, Wiesbaden (18U7), .S. 'Jfi-4:i.
II I'ani//a, B. Iticenjlu'sperinientali sopra i nervi. 8vo, I'avia (1884). Also
Abstr. in Edinb. M. and S. .1.. vok xlv. (1836). i)|). 70-98.
♦ I
(
Pi'
'n.
't
U; f.
ii:
H^'=
li
itiliH
898
TIIK NERVOUS SYSTKM.
Fl(i. 577. — Sclicnic of Iciwcr motor iicuroiif. Tlif motor cell liody, tofrctlii
all its itrotoiilasmic iiniccssfs, its axis-cylinder pi-occss. siilo tilirils, c
latci-als, and end ramilications. rciircscnt jiarts of a siMv;lf ctdl or iiv
ii.lt.. axon(-liill(M-k devoid of XissI iHidies, and sliowinn lihrillation ; ii.i
lylinder or a\one. This i)rocess, near the ceil liody, heconies surronni
inyelin, w., and a cellnlar sheath, tlie iieurilenima'. Ihi' latter not hei
iiite^'ral part of the lu'iirone ; c. cytoplasm showinj; NissI hodies and
},'r(innd sniistance; (/.. iirotoplasniic processes ulendritesi coiitainin
hodies; ».. nnelens; it'., nueleidns: »./.'.. node of IJanvier : .v./'.. side
».((/».. nucleus of iienrileinnia sheath : M.. motor end plate or telodem
m'., striped muscle lil)re ; .i.I.., segmentation of Lantermann.
r witli
)r <'(d-
itroite.
.. axis
led l.y
IK an
ifjhter
Nissl
lihril ;
Iriuu ;
"■^tii'i
GUOUPINU AND CIIAIXINCJ TOCI'miKK OK XKriiOXKS.
S<>J)
motor nerves are concerned, is to convey fibres to eacli muscle
from difTerent pjirts of tlie bruin and spinal cord.
The careful dissections and electrical cxperinionts of iVver*
proved that the group of muscles supplied by each spinal" root
was a complex one, and also that each muscle is supplied as a
rule by more than one root, findings which were confirmed in
large part aiul extended by the researches of Kruuse.t
The electrical experiments of Krb on the brachial plexus of
man made it seem jjrobable that the researches which had been
conducted ujjon lower animals also api)lied to the functional
relations of the roots in human beings.
Krom the clinical side, too, Remak J suggested that function-
ally related or synergic mus(;les are represented together in the ven-
tral horns of the spinal cord. He arrived at this conclusion from
his observations in cases of atrophic spinal paralysis, since he
observed that the muscles simultaneously affected corresjwiuled
to those concernetl in definite movements. He even went so far
as to indicate the probable position of the centres of certain
brachial and crural muscular groups in the cervical and lumbar
portions of the spinal cord respectively.
.Some help was gained with regard to motor localization at
this period from the study of the spinal cord after amputations
and from experiments on animals undertaken by von (iudden's
method. But the next significant advance in knowledge dates
from 18Sl,when the experiments with localized faradic excitation
were undertaken by Ferrier and Veo.* These investigators, by
stimulation of the individual ventral roots in the monkey, jiroved
not only that various muscles contract, but that a definite group
* Pcycr, .T. Ueber die pcriplierisplicn Erulif^ungeii cler iiiotorisuliLMi and
sensiblen Fasorii der in den IMoxus bracliialis dus Iviiiiiiielions eiiitretonden
Nervenwur/tdn. Ztsclir. f. rat. MwL. floidelb., 2 II.. 15(1. iv (1S.")4), S. ."ia-TT.
■f Krauso. W. Hi'itriige zm- Xoiirologie der oberen Extreiiiitat, 4l(i, I.eipz.
u. Fli'idolb. (1865).
X Remak, E. Ziir Pathogenesc der Rleiliihmungen. Arcli. f. I'syeliiat. u.
Xerveiikr., I?erl. (1876). — Zur Patliologie der Liihinuiigen des I'lexiis braclii-
alis. Berl. kliii. Wchnselir.. lid. xiv (18TT). S. 116-118.— Teber die Localisa-
tion atrophischer Spinalliiluuiuigeu luid s[)inaler Atropliieii : kliiiisclie 15oi-
triige zur Patholoijie uiid Physiologie des Uiic ken marks. Arch. 1'. Psycliiat.
u. Xerveiikr.. Berl., Hd. ix (1878-'T!»), S. r)10-(i;r).
* Ferrier, I)., and (1. F. Yeo. Tlie Functional Relations of tlie Motor
Roots of tlie Brachial and Lumbo-sacral Plexuses. Proc. Roy. Soc. Lond.,
vol. xxxii (1881). jip. 12-'iO.
1
i
^'
(
'1
it
WO
TIIK NKKVOUS SYSTKM.
of muscles in synergic couihiiiiition is set into activity, the effect
being to prodi; ■(• ji liiglily co-dnlinated movement such as K'emak
had suggested must l)e the case. They found, for exam(»k>, tliat
stimuhition of the Jirsf tliontcir root causes achiucition of the
tliumb and llexion of the lingers at the metacarpo-pluihiiigeal
joints; stimulation of tiic eiijlilh cvrrirnl root leads to a comp'ex
reaction, com|trising tirm closure of tlu' list (intrinsic; muscles
and long llexors of lingers and thumb), j)romition and llexion of
the wrist (to the ulnar side), and extension of the forearm with
retraction of tlie up{)er arm (long head of the tricej)s, especially
in action). Stimulation of the serentli ccrrictil root cau.sed
addu(.'tion of the upper arm witii rotation inward and retraction;
the forearm becajne extended s^) as to bring tlie dorsum of the
hand against the rump, the wrist and lingers being flexed (at
their second phalanges), the so-called scalptor (ini movement,
involving the co-operation of numerous muscles. In the same
wav they determined the complex movements which result on
stimulation of the ventral roots of (' vi, (' v, (' iv, S i, L vii, L vi,
L V, L iv, and L iii.
Since the muscles thrctwn into action by each ventral root are
innervated in most cases by several nerve trunks, Ferrier and
Yeo concluded that the ])lexiform junctions of the various roots
are for the purpose of distributing the requisite motor fibres in
dilferent trunks to the various muscles engaged in each functional
eombiuation. Such a view would explain why section of a motor
root, while causing paralysis of the (corresponding combiiuition,
need not necessarily paralyze the individual muscles involved,
and the remarkal)le lindings of Panizza were thus made less
unintelligible. These experiments were in large part confirmed
by Hert ami Marcacci,* and were confirmed and extended by
Forgue,t the latter investigator stating that each root passing to
the upper cr lower extremity supplies the two opposite surfaces
of the limb; that, in the cervical region, as the thoracic roots
are api)roached, tlic resulting muscular contractions involve the
* Bert, P., eil A. Marcacci. Cominunicazione preventiva sulla distribu-
zioiie delle radici inotrici nei inuscoli degli arti. Sporiinoiitale, Fireiize,
vol. xlviii (1881). pp. .'556-3.58.— Com pt. roiid. Soc. de Biol. (1881); also Gaz.
iiu'tl. de Pari.^ (1881). p. 513.
f Forguc. E. Distribution des racines motrices dans les muscles des
nieinbres. Gaz. lit'bd. d. sc. ini'd. de Montpel.. t. v (1883), p. 253; 27J); 321);
388.— Also These Muntjiellier (1883).
1
(iKoriMNCi AM) CllAININd T(>(iI<rniKI{ (*V NKriJOXKS. J»(ll
iiifi'ri(tr st'ginonts of the liinl), iiiul that, further. |i:issiiijx iti this
direction the contnictioiis projirossivcly involve the imiseiihir
massos proceed iiiif from the mdial to the uliuir side of the liiiih.
'i'he whoh' suhjeet was a<,'ain tiikeii up in IS'.f^ hy Ilisieii I{iis-
sell,* of London. Uiissell l)e<^aii his researcli by eiittiiiy iiidividiiul
roots and o.\citin<; tlio peripheral ends in onlur to observe the total
coMii)ound tuovenieiit produced. Subseipieiitly lie attempted to
make a minute analysis of this combined movement, dividing; it
into its component factors by usin^ minimal currents of excitation
applied to the separate bundles of nerve fibres in each nerve root.
1 le makes the remarkable statement that stimulation of each of the
various bundles visible on the surface of the transverse section of
a root leads to a dilTerent nntvement. lie attempted also, by ex-
citing successively the various roots and their parts, to find <nit
whence individiud muscles received their innervation. Again,
when a given muscle was found to be innervated from .several
ventral roots the attempt was nnide to determine to what dogroo
any given root supplies it.
It is imj)ossible here to give more than a single exam})le of the
results reached by this investigator, but for this the effect of
stimulation of the eighth cervical root and its constituent })arts
will serve very well. Wussell found that on excitation of the
whole root of the ciijlith rerviml nerre the whole uj)j)er limb be-
comes extended straight down by the side of the trunk i)arallel to
its long axis and in a straight line, with the digits very slightly
separated. Further, on excitation of the individual bundles of
the same nerve root he was able to ditt'erentiale no less than
twelve constituent movements : (1) Arm drawn to the side of
the trunk with tilting of the elbow outward ; {'2) arm drawn
down from the shoulder and fixed to the side; (:5) arm drawn
across the thorax to the opposite side ; (4) arm drawn to the same
side of the thorax; (5) retraction of the elt^ow ; ((i) extension of
the elbow ; (7) flexion of the wrist ; (8) extension of the wrist;
(9) supination of the forearm; (10) pronation of the forearm;
(11) flexion of the digits; (Vi) extension of the digits, liussell
determined that the fibres representing a certain movement, as a
rule, preserve the same position in a given nerve root. Thu.s, for
example, extension of the wrist is represented by a bundle of fibres
♦Russell. J. S. II. An Kx|)eritiuiil!il Investigation of the Nerve Roots
which enter into the F'ornmtion of the Bniehial Plexus of tlie Dog. Phil.
Tr. Roy. Soc. Loinl., vol. clxxxiv (H.). Loud. (18!M). i>\>. IJiMW.
I
,!
I
'S
}:
I
i:
{MI'J
TIIK NKIIV(H:S SYSTKM.
in tho ii])|i('r piirt of tlu! ciiciimffroiict!, \vliili> floxion is rcpro-
sciitud l)y ii l)iiii(lK' of til)r('rt in the lower part of the Huine root.
Kiifh bundle of nerve lihres re])resenting a sinj^lc! simple iiiove-
iiient in a nervo root remains, Ilussell states, distinct in its eourso
to the muscle or muscles producini; such a movement without
inoscidatinjj with other motor nerve liltres.
It is interesting to note that all the rectMit investigations indi-
cate that the group of muscles snpj)lied by any given root to u
litnl) occupies not only the anterior but also the posterior surfacie
of the limb; in other words, that muscles, the unimpeded action
of which would produce a certain movement, are rej)resented in
the same root as others, the action of which would jiroduce a
movement diametrically op))osito (antagoiustic muscles). In such
combinations, however, one set of muscles is always more exten-
sively represented than others, so that with sutllciently energetic
stimulation of all the fibres of a given nerve root certain muscular
contractions — for example, those of llexionof the joint — })redomi-
nate in their action over others. That the individual bundles of
fibres in the nerve roots do not go to single muscles is proved by
the fact that it is impossible by stimulation of siudi a single bundle
to produce contraction of a single muscle alone. As might have
been expected from what we know of the relation of the myotome
to the neurotome, when tlie same muscle is represented in two
nerve roots, the fibres of a muscle which are innervated by one
nerve root are not innervated by the other.
In general, these results have been confirmed by a whole series
of researches in embryology, comparative aiuitomy, clinical medi-
cine, jKithological aiuitomy, and experinu'iital physio'>gy. In
1888 M. .Vllen Starr* did great service by combining in the form
of a table the data which up to that date had been accumulated.
We produce here the table, slightly modified, including some of
the changes suggested by Edinger.
♦Starr. M. Allen. Syringomyelia; its Pathology and Clinical Features,
with a Study i>f a Case and Iteinarks upon it.s Diagnosis. Am. J. Med. Sc,
IMiihi.. n. s,."v<.l. xcv (188!^), p\K 45(]-4«i8.
^U-^^
m^^^M
,L
()ROUFM>f(> ANM) CHAININCl T()(}KTIIKI{ OF NKrUONKS. •>(»;{
LoaiJizaliini of Finir/ion in Ihr />ijf'frrtif Srcfiiirnt.^ of Hir Sjti ihiI
Corit. (.)/. Alhn Sl(tri\ slijilillji nioitijiid />// A'i/int/ir.)
m
Seftnu'iitH.
MimclfH.
Kftlt'Xis
C'lllillll-IIIIM llll-IIH
Illlii'l'Valril.
(.". ii-iii .M. ^liTiin-clciilo-iiiastui-
(irlis.
M. tni|M';(iiis.
Mm. sculciii L't colli,
I>iii|iliraL;iiiii.
C. iv I)iii|)liiiii,'iim.
M. sii|>i-iis|iiiiiiliis,
M. iiit'ms|iiiiiilii-<.
M. (It'li()i(ii'ii<^.
M. ')icc|)s hrui'liii.
M. CLnicD-ln'ticliiiilis.
M. sii|iiiiatiir Idii^us,
M. i'li(iiiilii>i(lt'i,
C.V M. (Irltdiilclis.
M. l>ic('|is linichii.
M. CDrae'd-tirfii'hialis,
M. siii)iiialiir !on;fiis.
M. su|iiiiat<ir l)n'vis.
M. i)i'cti>i'alis major
([lao claviciilai'is).
.M. serratii'. anterior.
Mm. rlmnlioiilt'i.
M. bnicliialis aiiliciis.
M. teres minor.
C. vi M. Ijiceps lirariiii.
I M. I>raeliiiilis amicus.
I M. i)eclnralis miijor
(pars ciavicularis).
M. scrratiis aTiterior.
.M. triceps Itnichii.
I Mm. extensorcs inamis ct
(ii^rjloriim.
I Mm. proiialores.
C. vil I M. triceps iiracliii (caput
; ioii<,nim).
Mm. extensorcs manus ct
tliiritorum.
Mm. Ilexorcs manus.
Jim. promitorcs mamis.
M. pc( toralis major
(pars sterno-coslalis).
M. suliscapularis.
M. latissii.ms dorsi,
1\I. teres major.
C. viii Mm. flexores manus et
(iijiilorum.
Mm. minores maims,
T. i Mm. extensorcs poliicis.
Mm. minores manus.
Mm. eminent, tlicnar. et
hypotlienar.
59
liispinitory rellcx Neck anil hack of
on ijuick pri'ssurc head.
Iicneutli rilis.
Dilatation of tlio NVck.
pupil on irrita- Tpjier jiart of
tjon of the neck shoulder.
(('. iv-vii). Outer side of arm.
Scapular reflex Mack of shoulder
(('. v-'i", i), and arm.
'rcndon reflexes of Outer side of up-
thc corrcsjiond- per arm and of
inij muscles. the forearm.
Tendon i-clloxes of Outer side of fore-
tlie .Mm. exicn- arm.
soi'es laci'rti ct l?ack of hand anil
i)racliii. radial rei^ion.
Tendol, reflexes of
tile inu.scles of
the wrist.
Rlow upon the
])alm of the hand K'adial rc^^inu of
causes closure of hand.
the finircrs.
I'almar reflex |
(C. vii-T. i).
Pupillary reflex.
Distrihution if
N. medianus.
J- Ulnar rej^ion.
1 I
i
am
i»(ii
rilK NKKVolS SVSI'KM.
1,111 iili .iiliiiH III' Fiuic/iii/i in llir Ih'tTirnif Sri/iinnfs i'/ /Ac Siiiim! ConL
( 'mifiiiKi'il.)
St'^inr?ils j
MuM-ll'M.
lil'lllXI'S,
Ciiliiiii'iius iiii'iis
iiiiii'i-viili'cl.
11 XII Aliii. ilul
Mm. jilMliiiiiiiiis.
.Mm. creel cirt"< spii
L. i M. ilii>|i-iiiiis.
M. siirturiiis.
Mm. iiliilomiii
II M. ilii)|is(i)is.
ijirlmiiis.
M.
^!m. llevures tjeinis
( ICemiiU '.)
.M. i|iiiiilriee|is femuris
L. iii M. qimclrieeps remnri
Mil
I. re il 11 1 ores leiiiun^
(iinviii-iii.
Mm. iiiliiiletiires feiiiori-
Ij. iv Mm. aliiliielni'es femiiri>
Mm. inldiielni'es femiiri>
M. lilliilli■^ iiMlerinr.
Mm. Ilexnres ijeiiiis
( Ferrier {)
1,. V Mm. roliitores t'emoris
U>iil wiinh.
Mm. ileXKl'es i;etiiis
(Ferrier ?;
Mm. Ilexnres peilis.
M
M
I"
m. exleii>cin
m. |ieri)iiii
ligilo-
S. iii Mm. HeXDres jietlis el IMiiiiljir rellex.
iliirili
Mil
M
11. lieldllM'l.
1
III. milii>re>- |ieili-;.
liieU (if lliiiili :
Kilter siile of lei,'
mill fool.
.^. 111 V
Mm.
lieriiia'i.
Veliiliesleilil
II
ex.
(Hire- Miili (i\('r sjieriiiii.
periiiM'iim. u'eiii
^ esiciil 1
eelll re:
111(1 reeitil taliii, and alioiit
'I'lii' .>;larlini,f [•oiiil for tlu> rcociit stiulu'.-^ of tlu* ejronpinjr of
tilt' lUTVo I'l'Us iii.";itlo tlu' s|iiiial cord is tlu' i'xli;ui.stivi> n'sciirnh
of WaUlt'ViT* u|)oii till' spinal conl of tlii> jjorilhi to wiiicli \vt>
havo alivatly ri't'crrctl. TIu' ejroiips ili-signatt'd liy liiiii, or modi-
ticatioiis (if tlu'st', art' still in iist>.
'riu' lu'xt iinportant rt'scarch hcariiii^ iqion tlu- topic now
• Waldeyer, \V. T>as norilla-ltiickeiimark. .Vliliaiidl. d. K. .Vkad. d.
Wisseiiseli. /.ll {{erlill (.{■'^■'*''<>. !^- !"•
()l{(»nMN(l AND CllAlNlMi nxiKTII KK OK N Kl'liON KS. jio;
onl
,ira\.
iiifii.
iiti'iil
•I of
liil
imur
far as
i>r siili'
|v and
mili'i-
.f ■ l.'i:
ac'fuin.
ilioiil.
uiuliT I'tinsidcratidii is thai, of Kaiser.* This author analw.nd
most. cari'fiiUy tlu^ work of pivvious iiivosti^ators uiul tlu'U liiin-
scir made an t'hiltoratc sttiiiy of
the cfll jiToups in the vontral
horns of tiio ciTvical n'uion of
I hi' spinal cord. Nor was \n\
Hiitisru'd with sini[>ly <jronpini;
the I'clls nior|)iioh>gically, Iml at-
tcniplfd to j^-ft at. till' functional
incaniiii;" of I hi' various groups of
I'l'lls in tlio vi'ntral horns. His
lindinjjjs arc illustralcil in I'i^s.
.MS to -">S".'.
The stuiiics of von I,cnl
losscK
have already heen referred to
(ridi' sN/>r(i).
Two .\nierican I'cseai'ches
worthy of .note must iiei'c lie
mentioned, thai of llaininond f
and thatof ('ollii\s.] llainniond
was able to state thai in the ihird
lumbar se<i;ment of the spinal
cord (l'"i,ir. ">S;>, A) the nucleus of
the (|uailriceps fenioris occupies
the nuddle part, of the ventro-
lateral column of cells in the
ventral horn ; a!, the level of the
tenth tboracie seirment I l-'iir. ."iS.'), c. rvical .(.ni a.cdnliiiK to Imumh.
I'lii. r)7S. Muscle liiulri ofllii' I1IIIII..II
mil I .aiiiii'ui'ai'c.
I Alter ( I. Kaisi'
I>) the cells of the abdomillid Die KmiUlionen .ler (iaiiKlieii/.U
m
iiscles are sitiiiiteil in the veii-
iles llalsniark
IlaaK, isiM, S.
■['lie lines niarUeil 7' anil /■')'
trodiitenil and intermcdiodatcrjil i'''^'' i'<'<n ihawn with n;.ar.l to n,.
columns; in the lower cervical
lilts ol'Tliiirlxiru ami I'lriieiaml
iny; "1
search
h wo
moi
U-
i\o\v
,1. il.
* Ivaisei-, ( >. Die l''iiiiil ion iler I iaiiiriien/elleii lies llulsiiiarkes. il.Mai
1S!)1.
\ ilaininoliil. (i. Two Cases of I'loelessive Miisenlar Alro|ili\ ;a |{e|iolt
if llie I'lilliDJoirical i!\;iiiiinalioii. w iili Speejal Keferii
lee to the 1' Uliel loliS
of Certain Ci-ll (Jroiips in tlie S|iiiial Conl. N. ^'. Meil. .1.. vol. |i\ ilS'.td,
pl>. l.') t!>.
J Collins,.!. A Cont riiiiil ion to the Aiiannenieiit ami I'linet ions of tiie
Ci'llsof the Cervical S|iinal Coril, to wliieli is A|i|ieiiileil a Note mi Central
ClliUliies Seeoiiilary to l.oiifj-eoiit iiiiied Disuse of One Mxl I'eiuil v. N. \'.
Meil. .1.. vol. lix (IHillK |ip. 40; !)S.
i
'•■t ft ^1
;!i. '.'ic
9or>
THE NF.RVOUS SYSTEM.
fif
N''. f
:^
! 'I
".'-■■\ ■-■■■4iim.
....... . . . ^^fii ^??&M', -^ :"Kii;''^. ,
•'•^■•■•-^•^«|lf#|fc■%
j/«. '■■■■■■■■:■■■.■■ '':^m'^
"^^•^ipA
.1 m.r.d.
I'Ui. r)7!l.— S|iiii;il niril nf iidtllt UlMll lit level i)t' ( ' 1 1 1. to slmw I lie Kl"lll'illK 'illlie
nerve rells. After (). Kiiiser, Die FimUtioiieii der (iaiiKlien/elleii <les Hills-
markes. etc.. IliuiK, IHIU, Till', ii. Kijj. -'. ) AiJi.. aeeessidius Ki'iiiii; /).//•-.,
Iiiisal eells lit' ilorsiil JKini : iii./i. f.'.. medial veiilral 'jniiip; .1/.:, middle cells ;
St./.. iiiielelis dcirsalis (eervieal iiiuleiis nf Slilliii-;); N", eells of eorilll
latenile ; r.f.'.. veiiti-.ll };riiu|) ; :/, sealleied eells.
T^^WBP'^li^
«
.:\\;^^
7
y\\\ii lit ilu'
.Us Mills
|M>
/,. ;/:.
(lie <t
lis
111" ('(irmi
...-.>4-
1(1
^''-\
^^^'
/
/
Viu. 580. — Tnuisvcrsf scrlioii lliroiiKli human spiiia! conl at level of (' V. (Aft<'r
(). Kaiser, Die Fuiiktidiieii (Kt (iaiiKlieii/.elleu des llalsiiinrkes, etc., Haag,
18!tl, Taf. iv, KIk. 1. i .Icf.'., acces.s( riiis {jroiip ; /.(.'./. lat<'nil nnnip 1 : l.a.k,
Ial4'rsil uroup 2; tJI.A. lal«'ral unmpU; inAI.. medial jrvciiip ; jU;. middle
eells ; '.<z, cells of ((ifiiii laterale ; e.a., \eiitr.il fiioiip.
4'*';
llf
I
»■((
■i:il
IH'
[L,
{♦08
TIJE NKlJVors SYSTEM.
Flu. 581. — Tr.insvcrsi' sci'tioii tliroiijjli tin- liiimaii spinal coril at tlif level of
("VIII. i.Xrtir (>. Kaistr, Die r'uiiklioncn dcr ( iaiiKlii'ii/cileii des Ilals-
inarkcs, otc, Haas, isiil, 'Pal', vii, Kij;. 7. i /.//.'.., lateral dorsal ki'""!' ; l-iJl.,
lateral ventral Kmup; iu,(!.. medial group; M~, middle eells.
GUOUIMNd AND ('IIAlMN(i TOUMTilEU (»!•' NKIUONKS.
IM»'J
rcfrion ( Fij;. .")S:{, (') tlie lUK'lci (.f the ii;ii,s<'lt's of the forourni are
t^itiiatod ill the voiitro-hitoral culiiiiiii, wliile tlie imisck'S of tlio
hand aro ruprt'seiited boliind these in tho most dorsal and in-
ferior parts of the nucleus of tlie superior extremity.
Collins compared the cervical enlar^-emcnt from a normal
cord with that from a case of jiolio'.nyclitis. \i\ careful exami-
nation of serial sections he cont liulcd that the vast majority of
the motor cells of the cervical cord show a delinite arranjre-
ment ; that certain of those cells form columns which extend
til rou<rh several spinal sc<,niients; that lieflnite functions can he
attributed to certain groujis and to certain columns of cells iii-
■l.d.G.
Fid. 5S;>. — Transverse seetioiis of the I'lelal liiiinaii ediil IS." em. liiiij;. .\fterO.
Kiliser, Die Kiinklidiieii der (laiit,'lieiizelleii lies Ilalsiiiaikes, etc., ]laaK, Isitl,
'I'af. ix, Kij,'. Ill" and I'i.u. l(l/y. i a. .Iiiiietinii iil' ( ' \' witli ( ' VI. h. .Inuetidii
ot'C VII willi (' VIII. "c. 'i'.. aeeessiiriiiSKioiili ; L<1. 1,1.(1. J, 1.(1..',. three pur-
tions ot' hiteral ^I'laip; l.il.d., lateral ilorsil groiin ; l.r.<i., luUral ventral
Kroup ; m.<l.. medial ;;nin|i.
side the spinal con] ; that the main cellular groups correspond-
ing to the brachial plexus are three in number, and extend from
the upper jiart of the fourth cervical segment to the iover jiart
of the first thoracic segment, the cells of the upper part of this
territory innervating the muscles of the shoulder and of the
arm, the cells of the lower part innervating the muscles of the
arm and of the hand. The group of cells innervating the flexor
muscles is situated outside and below that innervating the ex-
tensor muscles. On the other hand, the cells innervating the
extensor muscles are more medially placed than those innervat-
ing the flexors, 'i'lie muscles of the back are innervated, lie l)e-
SHO
TllK NKRVOirs SYSTKM.
liuvcw, by tlie cells situated ventnilly iind iiu'dially in the ventnil
liorii. Collins believes that the luiinlxT of ct'lls and ( ell {groups
is in direct relation with the motor i'lmctions of the parts corre-
sponding to tlieni topograpiiieally. 'I'lie luicleiis for tlu^ phreidc
nerve, according to Collina, occupies the ventro-medial portion
of the ventral horn at tl lower part of the third cervical seg-
ment (Fig. ■>84).
The localization of cells corresponding to various muscles
entered upon a new era with the introduction of the 8})ecial
method devised by Nissl in IS94.* Tliis method yMethodr (tvr
priihiiren Rcizuay), and some of the residts to which it has led,
have already been referred to in Chai)t('i X\. Itdepends u])on the
fact that if the axone of a lower motor neurone be severed, certain
definite and easily recognizable changes oc(!ur in the cell body
of that neurone. There is disintegration or disappearance of the
tigroid masses in the protoplasm, and the luiclei.s beconu's dis-
located to the side of the cell. 'I'he inventor's application of
his own method was not so happy as that of recent investiga-
Fi(i. .'jH;?. — (Jniiipiiif; of >fll IxMlics of lowrr motor ni'unincs imiorvatiiiK various
imisclcs. (Alter (i. llainiiKind, N. Y. M. .1., lKi>4, as modified liy V. Sano. i
A. Level of \j III. cells KoveniiiiK M. i("i"'''ieeps femoris. 15. I>ev<>l of T X,
cells iiiiiervatiiit; the alMloiiiiiial iiiiisele.s. ('. Level of inferior cervical cord ;
ventral nucleus t;overnin<; muscles <if forearm ; dorso-latenil nucleus govern-
in;; intrinsic muscles of tlie hand.
tors, for, instead of .'.xtirpating individual muscles, Xissl cut defi-
nite nerves such as the radial, the tdtuir, and the median. lie
found changes in ceils in the spinal cord, not in compact groups,
but nu)re or less at intervals, a fact which is not surprising
* Nissl. V. Ucber cine iieuo Unlersuchungstnethodt^ des rontrnlorpans
spcciell zur Keststcllung der liuealisatioii der Nervenzellen. C'eiUralhl. f.
Nerveiilieilk. u. P.sychiat., Oobletiz. u. Leipz.. Hd. xvii (1H94). S. ;{;?7-:!T4 :
also in Areh. f. Psychiat. u. Nerveidxr.. Her!.. Hd. xxvi (1894), S. 5!)7-61'2.
(J|{(H;iMN(> ANF) CIIAININC} T(»(JHTIIKI{ OF NKrHONKS. (HI
cord ;
kivcrn-
defi-
ne
hups,
lisiiig
li-t;ans
llhl. f.
-:!74 :
•>
wlmii Olio considers Mk* ceiitral iiiid |tcriitlu'ral rcliitions of those
iiorvos, iiiid tluKSo of the noiirotoiiics iiiid inyotoinos to wliich
thoy oorrospond. His results luivo been in general foiilirnied by
('ohfiibriindor,* by Marinos{'o,f
Khit'Ui, J iuid by otiiors. liy
nioiinsof tiiis inothod uttciiipls
at locali/atioii in tiio ' ucloiis
nervi otniloinotorii liavc been
made by H(iridioitnor* and
Schwabo II (ride infra).
,]. Krhinjfor, in I'rof. iMalTs
laboratory in lialtimoro, "lias
used this method to determine
the position of the cells in tlie
spinal coni, which innervate '''i';- •wi- iHiiKiam di' the lumiim spiiuil
. , . ... ciiid at till- level (pfC III IVdiii a case of
tlie biceps niliscio in l'at)bltS. pclicnivelilis. . After . I. Collins, N. v.
After extirpating the mnscle IJn^^l.i:!; ;:r,i;::'';.S:!,S.^,.:;;';::''
or cutting the motor nerve go-
ing to it he studied the changes in serial sections in the spintil
cord, the animals having been killed llfteen days after the experi-
ments.
A most important series of researches in this connection have
been undertaken by Sano,'^ who has studied a number of si)inal
cords by Nissl's method after amputation, and has made a num-
ber of ingenious experiments on cats, pigeons, and rabbits. From
* ('olciihnmdcr. Over fie Slructmir der (iuii{,'lienfel nil <1eii lioorsteii
Ildorii (IHiXt), eited hy Saiiu.
t Marincsc'o. Op. cit.
X Op. vil.
* licrnlicimcf, S. Ztir Keiintiiiss der LocalisiiUoii in KeiTi^'chielu des
Ocidomoloriiis. Wien. kliii. Wchnschr., Hd. ix (1806). No. .'5.
I Schwftbc, II. Uclicf die (iliederiinj; des ( )culomotnriiisliau|it kerns mid
di(! Ijiitjo der den eiiizeluen Miiskelii eritspiTcliciiden Gebiete in deiiisulben.
Neurol. Centralltl.. Leipz.. Hd. xv (IHfWJ). S. 7!»3-794.
^ Sano. F. lips localisation niotriccs dans la nioelle lottiljo-sacrec. J.
de TKMirol. ct hy()no]., i'ar., t. ii (1H!)7): Li's localisations inotriccs dans la
inonllc ('itiniere. Cornnnmication au Congros de Neurologie et d'llypnologie,
Scptenibrc. Rruxelies. Resume dans le .1. de neurol. et liypnol.. 1897;
IjCS localisations des fonctions inotri(!es de la nioelle epinierc. .\nnales
(Ic la S(iC'iet«' Mi'dico-('Iiirur{;ieale d'Anvers. 1(» Novembre (1807): De
lii constitution des noyaux nioteurs niedullaires. .1. de neurol. et liypnol.
(1808). p. 02: Localisations niedullaires motrices et sensitives. /'-W. (1808),
p. 120.
912
TIIK NKUVors SVSTKM.
the results of tlip'^o mid a very careful con-sidenition of the liter-
ature, this author hus formulated his views eoiieeriiiug the eoii-
9S 4 3 6 f
e
<j
i'^
vs *
V.
W'
■Utt
;»7
Fl<i. HH'i. — ('iiliiinns of jii'iiy iiiiillt'i" and inntor iiiicli'i of iiitiiiucscciitiii cci'viciilis.
(Al'ttr !•". Sill II I, l.t's Loral isit ions dcs t'onctions inol rices dc la nioclif ('pinii'rc.
AnviTs. I'riixcllt'S. IS'tS, |). ;i2. ' ('iihiniiin iiifilidli.s — /. ii, short rotators of
head ; M. snldiyoid iniisclfs ; h. i-.d. r./, extensors and rotators of the vertelinil
eohnnn. .'. inielensiliapliraaniatis ( t lie series of sympathetic nni'lei coin posed
of small cells have not hecii drawn in ' ; tliey are situated Ixdiind the coliiinna
medialis near the c(dniiilia calialis eentra'lis. ('i)hiiini(i iiilcniK'tHii-hiliriiUs — >'.
((, accessoriils M. trapezius ami M. sterno-cleido-miistoidells ; /). c, plexus
cervicalis : Mm, trape/.iiis stcriio-clcido-niastoideiis ; </, c, middle portion of M.
trapezius; /. inferior part of .M. tiapeziiis ; c, hi'itinniiif,' of the nucleus for
the M. latissiliius dorsi. ('uliiiiiiiii I'.ilriuiiiliilis siijii'iioris — ■!. Mm. pcctorales;
/f. Ii, M. levator sca])llhe : c, M. seriatus major; '/, muscles of the slioiihler ;
7. t; M. hiceps ; lower down supinators and extensors of the tinkers ; hetween
(/and (' llexores and ju'oiiators ; c, thenar and hyi)otlieiiar muscles; /, liypo-
theiiar muscles ; ,». tl. M triceps lirachii ; c. M. ancomeus.
stitution of the columus of motor cells in the spinal cord. His
work is of value and interest and should he consulted by every
one who wishes to become familiar with the most recent findings
dealing with spinal motor localization.
In brief, Sano distinguishes, as do most neurologists, in the
ventral horn two louiritudiual columns of motor cells Avhich are
OKOl'lMNd ANI> CIIAININii 'IN Mil;'!' I! MU (>|' Ni;ri!n.\HS. t»l;{
almost coiistunt tlinm^'liout tlio wlioU- length of the ford — tiio
coliimna mi'iliaJis atnl tin- mlnmiKi i/tfrniirdin/n/rni/iy ;* on
tmnsverse section tljcsc uro desijjjnaii'il the iiiirlci nietlialcs and
the nuclei internu'dioluteralcs. Kai'ii of tlit"<(' (dluinns may lu!
subdivided in places into two, three, oi- four seeondarv columns.
Ik'tween the colnmna modialis and the colunma iiitcrmedio-
93^5^7
I'm. r)S(i.— ('ohmiiis (if ^niv iiiMtlci' iiiid iiiiildr iMulti ol' the iiitiinicsct'iili:! liini-
liiilis. (AI'tiT A. SaiKi, l.cs I.nciilisiitiims (Ics I'diiclidiis iiiuliiirs dr In iimcllc
(''|iiliii'Tc, Alivcrs. linixcllcs, 1S!,«. ]i. :}:}. i Cohniiiiii iiiiili(ili'<— I. il, h. i, i-\-
tclisiir anil icittitur iiiilsclcs of tlic spine ; j, L\ iiui-^iMiliis iscliidciiccynciis anil
M. levatiif ani ; .'. A, in IViint M. spliimliv vcsicalis ; .pcliinil .U. M. spliinctiT
ani ; tlie synipatlietic nnrici arc mil li;,'uii<l I'lirllie visrcral niiiscUs. Ciiliiiiiiin
iiilfniif<liiiliitfiiilis—S. ij. aliilunnnal unisrles ; li. M. creniaslcr ; ./', A. inlisrics
III' the perineum. Ciihiiiiiiii fxifciii'iliilis liifrriiiris — .'. (', M. pyiainiilales ; •■. Ii.
M. iliii-p.siias ; /. Mm. j-'lntiei : ,;', Mm. nenielli. M. iiyiirormis ; (, M. i|nailri<eiis
reinoris: ■'>. M. pertuntns ; Mm. aililiirttires ; 'i'. /. Ilexnis nl' the knee: lower
ilowii M. piiplitiiis. .M. tiiieps siine, .;' ; T. h, M. liliialis antiius: (, extensor
nuiseles of tile toes. ^^m. iieronei ; lower ilown. M. liliialis postirns ; Ili'Xors
of the toes ; ./, A', intrinsic musehs of the foot.
^ I
* The torm poluir.na interinodio-hitoralis eorfespomls to the Scitcnhfini-
£*7/e« of Waldeyer. 'I'hese. tofj;etlier with Ills .l////('/i/'//(';(, eorn'sptniil to .1.
Lockhart ("lurke's Tfaettis intenneiHo-lateraUs. deseriheil in his Further
Kescarc'lies on the (iray Siil)sta»;ee of t)ie Spinal Cord. I'iiil. Trans. Roy. Sou.,
Loud., IJd. exli.v (1859).
fl'^
{♦14
TIIK NKHVOUS SYSTEM.
latcrulis tlicro arc intprcalatcd, in the cervical atul lumbar en-
lur<;ciiiciits, loiif^itiidiiial motor nuclei of considerable size wiiicli
are related es|»ecially to the muscles •)!' the extremities. These
intercalated nuclei are known in tho cervical onlar{i[emcnt as tho
volnmnn extrcmifah's nvpcrioris (Kaiser's nucleus cxtromitatis
superioris), and in tiic lumbar enlargement as i\\v column a cx-
treiii ihttis iiifvriiiris.
In Fig. AS.") the various i.iidei in the cervical eidargemont are
shown not only in their longitudinal ext(!nt, but also in their
reciprocal j)osit''ins in transverse f.ection. In Fig. ."iSfi the motor
nuclei of the luml)ar enlargement are re])resente<l. If the
legeiuls accompanying these be carefully consulted they will, it
is believed, be understood without further descriptioji. It is to
he renu'inbered that not every one of these nuclei has as yet
been definitely established by means of Nissl's nu'thod, but the
ligurcs reitresent accurately the present status of knowledge
gained from a great nuiny diilcrent sources. The articles of
Flatau * and van CJehuchton f may with profit be consulted in
this connection.
On the whole, then, it is seen that in the spiiuU cord ea(di
muscle is represented by a nucleus of ventral horn cells. Further,
eaidi segment of the spinal cord nuiy contain portions of the
nuclei of a number of diiferent muscles; and these portions,
jmlging from electrical excitation of a whole ventral root, may
correspond to a very coinplcx movenuMit. Section of the ventral
root, as Warrington has shown, leails to degeneration of the nerve
cells in all the groups in a given segment. Uussell's experi-
ments, in which he excited electrically the individual bundles of
a single ventral root, render it almost certain that the very com-
plex movement represented in a whole ventral root can be ami-
lyzed into a large .series of simpler component movements. The
nerve cells corresponding to these individiuil simpler component
movements have not been localized inside the spinal cord, but
there can be but little doubt that they will be at some later
time.
* Flatau. K. Uober Verilndennigen im mi^nschlichen RUt^kcninark nacli
Wcpfall prosserer GlipdtnassL'ii. Deal. med. Wehnselir., Hd. xxiii (1897),
S. 278-2T!t.
f van Gi'huehton. A. L'Ariatomie fine de la cellule nerveuse. Verlmndl.
d. Internal. Congr., Moscow, 181)7.
(B) Those pertaining to the Rhombencephalon, Isthmus, and
Mesencephalon.
tijr
('nAI"IVKU I. VI.
TTIK I,()\Vi:u MOTOK NKTKOXKS (fONTI \ f KP).
Lnwor motor nciiroiirs nljove the s|)iiiiil cord — Cohimim intHliiilis— C'oliimna
latonilis — Ciirvos of cctitfal cuiiiil — 'I'lic su-ciillcd " licail-cavilics" —
I'roxiinal or jiroiitic cavitiL's — Distal or jiostotic i-avities — ('L'|ilialic
myotoiiu's — The so-callctl " compont'iils " of the pcriplicral tuTvcs —
Somatic motor, .somatic sensory, visceral motor, visceral sensury, and
acustico-lateral components — N. hypojjlossus — N. aca-essorius — N. vagus
— X. slossopharyn<,'eus — N. facialis — \. alidncens — N. trigeminus — N.
trochlearis — N. oculoiiuitoriiis,
'I'llM lower motor iiouruiu'.s jn-rtiiiiiiiig to the rlioinl)oti('t'j)liidon
and niosoticoplialoii are those the axoiio.s of wliich <jo to make up
the motor cerebral nerves. Continuous with the motor gray
columns in the cord are similar colinnns, though loss regular and
more interrupted in tlic medulla, pons, and midbrain. The
motor cells in these upju-r regions (Kig. 5Si) are divided into two
very distinct longitudinal masses, one placed more medially,
the other more laterally. To the medial column passing from
below upward belong the nucleus X. hypoglossi and the nmdeus
X. abducentis; while to the liiteral column passing from below
upward belong the motor nuclei of the \. accessorius, X. vagus,
X\ glossopharyngeu.s, X'. facialis, X. trigeminus, and probably
also the nucleus N. trochlemis and the nucleus X. oculomotorii,
although there is some doubt as to whether the last two nuclei
belonjr to the lateral or to the medial column of motor cells. In
the medulla oblongata the motor cells form almost a continuous
column, but in the pons, isthnnis, and midbrain there are wide
interspaces between the groups of motor cells.
The central canal, in passing from the cord to the ventriculus
tertius, shows two marked curves. The first is at the junction of
cord and medulla, wliere the canal curves rapidly dorsalward to
915
•P^
^ (
\Hi
! »
!)it;
TIIK NKIf vol's SYSTKM.
opt'ii into the vcntric'uliis quiirtus. 'I'lii' st't-i.iid in ubovo the
uqiu'diu'tus ci'i-cliri (Sylvii), where tlie eiiniil curveH veiitrulwnrd
to enter the veiitrieiihis terthis. It will he noticed that the loii^'i-
tiidiiiiil fihres near the raphe follow the same cuive. Opposite'
Dii'ticviihalon.
iU'ni'iicriihdlon.
,. Nrrviigoruln-
ir.uloriuH.
hthinuii I't tier-
ruHtnicliUaria.
Cfrrliel-
I mil.
Eprnilyma.
Xrrnis tri-
llflllillHU.
\<'rritn (iriii:-
iicii.i.
I'lis i/lo.im)])hn-
rymjins.
•if Xervtis viiiiiis.
Xervtis acccsaori'is
Fio. r)h7. — Hiaiii. slidwiiifr tlu' (irifiiii ami toniiinafioii of the iicrvi ccrcbriilcs ;
liuiiiaii ciiibryo. From a rccoiist ruction cularfjcd ahoiit ciijlitccii tiini's."
(After W. Mis, taken from .1. Kollmaiin's I.elirlimli der Hiit\vi<'keliiiij; ,{;e-
sehicliten des .Meu.selien, .(elia, l«i)8, S. 5tL*. l-'if;. 'SM.i Ti\ tuber eiuereuin •
//, hypoijliysis.
the lower curve the fibres of the fasciculus ventralis proprius pass
dorsalward to enter the f'-isciculus longitudinalis meditilis. Opjm-
site the upper curve tde fibres of the fasciculus longitudinalis
medialis past: veutralwtird to the region of the nucleus fasciculi
(JUoriMNd AM) CIIAINIXCJ TOCIKTII KU <i|' NKlltoNKS. <»17
Irclir.ilcs ;
I'll tiiins.
liifiruiii ;
fus pass
Oppo-
lidiiiiilis
lascieuli
loiiffituiliniilis iiu'ilialis (imch'ux nf |)utksclio\vitscli). 'I'lic twct
(•(•n'linil iiKttor mick'i of tlicso regit). is imiiicly, tin- iiucloUo-Iicrvi
liypdgldssi and tlic nucleus iiervi (tculoniotorii — emiform also to
the curve, so tluit when looked at from tlio side, those two nuclei
are seen to lie ohli(piely to the long axis of the luedulla, pons,
and niidhrain.
The cell bodies in all these nuclei are very niucii like those of
the Hpinal motor cells, being typical multipolar stichochrome
cells. Their axones plunge out as a rule almost directly into
the [)t'ri[iheral nerves. The exceptions to this rule are met with
in the motor axones of the ninth iiiid tenth, which run backward
from the nucleus ambiguus toward the lloctr of the ventricle, then
to run out in the same bundle in which enter the sensory portions
of these nerves. The fibres of the seventh nerve nuike a reimirk-
able discnrsion after leaving their nucleus, '"hey pass upward
and .medial ward {pars prima) to the inner side of the nucleus
nervi abducentis, then pass cerebralward along the floor of the
fourth ventricle for a short distance {(H'liu internum), and again
turn lateralward and afterward ventralward [para serunda), to
take their exit from the ci'utral nervous system at the junction
of the medulla with the pons. The most remarkable behavior
of axones is perhaps that met with in connection with the fou''th
cerebral nerve. Although the nucleus N. trochlearis is situated
in the isthmus ventral to the atjueductua cerebri, all its axones
pass dorsal to the atpuvluct, and undergo total decussation with
the fibres from the opposite side. The relations of the cerebral
and upper spinal nerve roots to the central nervous system are
clearly visible in Fig. r)88.
The axones of the cerebral motor nerves run in the peripheral
nerve trunks to the muscles which they govern, and end on the
muscle fibres as typical motor telodend'-ions, just as do the spinal
nerves. The periods of myelinizatio'i of the various cerebral
nerves has recently been very carefully established by Westjthal.*
Much work has been done, especially from the embryological
side, with the view of estal)lishing the exact relation of the lower
motor neurones corresponding to the cerebral nerves and the
muscles which they supply. It would appear that the muscles
\
\
* W('stj)hal, A. I'pber die Markschi'i(li'iil)il(limf,' der Gchirnnorvpn
dps Moiiselicu. Arch. f. Psychiat. u. Xcrvciikr., HitI., Bd. xxix (18"J7), S.
474-527.
I) IS
THE NKHVOUS SYSTKM.
of tln« lu'iid, of tlio t'vt's, iiiitl of llio miiltlK' i-iir arisi« from cortuin
S()-oalU'(l " hcail i-iivilit's," wliioli iippi'iir at a contain porioii of
(Joveloj)inont in tlio njosoderni of tlio hcuil. As lias been pointed
Km. .'SSH. ('< Tctiiimi, witli ii iinrtioii of tlic spinal cdvil, vifwi'il I'rom ilic vciitnil
stiiraii'. (Ml llii' rinlit-liiiiul side Ilic vi'iilr;il imils :\rr fill nil' short and
(luiuil tiuili;ilw:ii(l. (Al'lir Uiitliiiycr anil lltiili', iVuiii A, ICaiilii'i's trxt-
liiHik. ) /, tfaiHis oH'actoriiis ; //. tnuliis (i|ili(iis ; ///, N. (Muliiiiicilnriiis ;
/I'. N. troiliUaiis ; T, N. Iiifjtiiiimis, purlin iiia.jcir tl pmlin niiiinr; I/, N.
alidilci'iis; 17/, N. lacialis; 17/', N. iiil. riin'iliiis; I III. N . aciislicus ; /.V,
N. kI<i^^<'I''''"'.V"i;''<Is ; A'. N. va«us; A/. N. acccssoiiiis ; Ml. N. Iiypnfjlossiis ;
iir /, N. crrvicalis piiiiiiis.
UUoriMNO AND ('llAlNIN(i T()()KTIIKI{ OV NKl'UONKS. <(H>
m
in
of
ed
'H
HI
lie I
I ulnil
aiiit
U'Xt
ln'ius -,
■/. N.
IX.
Iissus ;
out in CliapttT X \ 1 11, tlioro is sutiio dispiiU' as to tin- I'xin't im-
turp uiul orijfin of tliosf licml cuvitios. WIumvus inuiiy obsorviTs,
aiitl it would sctMii tlu' uuijorily at prosout, look upoii tlu-iu as piir-
tions of uivotouit's, otiuTs ivi^anl tluMU as corri'spondinij; to rut-
otT portions of tlu' hody ravity. According,' to tlu' fornuT viinv,
tlu' niusi'los of tlio lu'ad and eyi's wouKl hv a part of tlio general
skeletal musculature, while ae(U)rdinti[ to the second view they
would represent portions of the visceral musculature.
Assuniiufj; for the moment that they are portions of the skele-
tal musculal ure, and liave their iirigin in myotomes, it will ho
interestinj; to refer, if only l)rieny, to the views held with repird
to certain details of their dev»'lopnu'nt. Most observers seem to
look upon the " head cavities "' as corrcspondinjr to the ventral
tit'his of the myotomes, tlu; dorsal tieUls havinij disappeared,
owing to tlu' great extent of the capsule of the brain, which, on
account of its tirnnu'ss and immobility, nuikes a dorsal nuiseu-
latiirc superlluous (KoUmann).
The relations have been perhaps best studied m the bony
tishcs in which nine cephalic myotomes are distinguished, four
of which are proximal or pro()tic that is, lying in fi'ont of the
auditory vesicle and live distal or postotic, lying behind the
auditory vesicle.* Thus far the prootic cephalic cavities have
not be(>n made out in man or in nuimmals, although it is not
impo.ssible that tiaces of them may yet be found. The relation
of the iiulividual muscles in man to cephalic myotonu-s is up to
the present tinu' larg(>ly a matter of speculalion, but it is believed
that the muscles supplieil by the N . ocidomotorius are cU'rived
from the lirst proidic myotome or ccphtdic cavity (I'^ig. .")S;t), tho
mu.scdes supplit'd by the N. trochli'aris from the second prootic
myotome, ami the mu.scles supplied 1m the N. abduccns from the
third myotome.
The fourth myotouu' is supposed io give ri.-^e to the muscles
of mastication ( i''ig. o'.tO), the M. tcn.>;or tympani and the M. ten-
sor veli palatini, all supplied by the motor part of the N. tri-
♦ The rfiidt-r is rcfiMivd to I lie nrt iilc.-- of (Ic^ciilmur, vim \Vii;lii>, Knlil,
luMilor, Ilarrismi, Coniiiiu, iitiil I'spciiully to llu' |uililiiatioiis of von KiiiitTcr,
("., Die I'jilwirkfliiMH' v(Mi lV.!"iny/oii I'lioiori. Anli. f. mikr. Aiml., Monii,
Htl. XXXV. (IS!»0), S. -l(i!) 'mS.— Tlie Dovfloiinii'iil of IlicCnmiiil Nerves of
Vcrti'liratfs. .1. Coiiiii. NtMirol., ("iiicin., vol. i Of^i'l), |). •JItl. .\nil .'^ludii'ii
y.iir viMirliMi'lu-adi'ii I'liit \vi('iii'liiiif;sj;i'srlii(liti' diT Kniinoli-ii. Miliulicii, 11.
», 18!»r).
tit)
* i
92(»
Till-; NMKVOUS SYSTEM.
geiniiius. Ft has been sujij^ested also tliiit the M. mylohyoideus
and tlio iintorior hdly of tlio M. (li<,fastriciis, on account of tlieir
innervation, are also derived from the fourth ceplialic cavity.
Diviifciilidloii.
■ Kjctirnitl layer.
'<• r.eiis (•('.s/c/c.
li'rtiiKll Itiijir.
i, - tat cvjilitiUc I'd rill/.
' ,i -.KvUxlvriii.
Fl(i. .'isit. — First (■('|)Ii:ilic cavity; ))rii'clii)nliil purl ol' skull, l/iccria viiidis nf
twcnty-civ'lit piiniilivc si^Miicnls. Aflcra pnparalinii by ('((niiiiu. IViPiii .1.
Kdlliiiami's Lclirhiicli diT iMitwirkcliinfisficscliiclitcdcs Mciisclicii, .liiia, ISDH,
S. -ZM, Fi^^ li>7. )
Tlie myotome corresponding to tlie N. facialis gives rise to the
whole musculature of the face, the platysma, the M. stapedius,
the M. levator veli palatini, and the M. uvula'.
The ventral processes of the five postotic myotomes (lying in
the chordal part of the head) give rise in the bony fishes and in
rej)tiles to the muscles of the tongue (Fig. a!)!). This has not
been definitely proved in man and mammals, but from the be-
havior of the N. Ixypoglossus and the relations of this nerve to
the muscles concerned, it seems likely that a similar origin will
be found true in them.
The X. access(n'ius is j)rimarily a spinal nerve, and the myo-
tomes corresponding to it arc myotomes of the trunk, notce])halic
myotonies.
The comparative morpliology of this region, so important for
the proper understanding of the problems of cei)halogenesis, has
been discussed in a recent paper by Fiirbringer.*
♦FiirhriiigiT. ^f. UoluT die spino-dCfipilaleii Nerven dcr SeliichitT iiiid
Iloloceplmleu und iiire viTgleiclicude MorplKiloi^io. l"\'sts('lirift f. Ocfjcn-
W^'^f^ftrn lj,,wi^-, ,, ,
|1!
mg m
md in
us not
the bo-
n-ve to
11
[\n wi
niva-
lin
iilio
it for
hiia
jlS.
GIlOL'PlMi AM) C'llAlNlN(i TodKTllKi; OK MURoNES. !)2l
'riio ('oinpiirativo iiiorpliology of tlio corohral nerves has been
carefully studied, by lluxlev, (iegeid)aur, Strou;^:, Kwart, llerrick,
Kitiffsbury, I'inkus, Cole, Allis, K. L. Mark and his assoeiiites,
anil others.
This seems a suitable place to mention the iileas whieh have
♦»een developed, especially by American morplioloj^'ists, concerniiif^
tho, ciun/xjnriifs (if the peripheral nerves. In this connection tlie
researches of Strong,', llcrrick,* Shore, Cole, Kingsbury, f .Iohn.s-
ton,|. and others tjiay be referred to.
it. 1(111 i>iiriil in.-
/Voi'C.s'.sKs CdiiihilDiilriix.
M. iliitsfii'lrr.-
Proc. coionoidvnu.
(t<iii;)li(in nciiiiliiiKiri' daxmri.
Mm. iidriiij. int. it I'.tl.
.yffikil'.i viiitHiujf.
Kl(i. r>iM). — ncvcliiidiicnt III' uiiimIcs (pf iiiiisticatioii. Kccimslnictiini fnnii m iiifi's
(■inliiyip IS iiiin. 1(111},'. (Allir KculiT. liiktu Innii .1, KoUniiiiiirs l.tlirlpmh
(Icr KiitwickcluiiKSKcscliiclitc lies MciimIuh, S. •Jit.'), I'Mj;. KiH.)
These investigators recognize in a typical spinal nerve (in the
gnathostome vertebrates) four diiferent components:
(1) A somatic motor component originating in the ventral
horn cells.
("2) A somatic sensory or general cutaneous component, the
axones terminating in the dorsal horn.
(3) A visceral motor comi)onent.
(4) \ visceral sensory component. The exact central rela-
tions of the visceral components have not yet been satisfactorily
worked out, though the general opinion seems to be that the sen-
baiir, Leipz. (1897), S. ;}r)l-TH8. HciTk-k has inibUfilied ii full rcniow of this
article. toi,'ot her with tables illiistratiuj: the metamerism of the sjiiniil ami
eerelinil nerves, in the .(mwiial (if ('(im|iarative Neiiroloj,'}', vol. vii (1H!»S). pp.
25-48.
* Ilerriek. ( '. .1. The Cranial Nerves of the iJony Fishes, .f. Com)).
Neiinil.. Oraiiville. vol. viii (IH'.IM). pp. KW-lTO.
t Kint,'shnry, H. l'\ Tlio Encephalic Evagination in (ianoiti-. .1. ('(>m|>.
Neurol., (ivanville, vol. vii (ISitT). p. :'.T.
t Julmston, .1. B. Anat. Auz.. Jena. Mil. xiv (189G), S. 2^-'.^!.
922
TllK NKllVOUS SYSTEM.
sory viscerul libres enter the uord by the dorsal root, tho visceral
motor iibres leave the cord by tiie ventral root, in higher mam-
mals, and bv both dorsal and ventral roots in inframammaliaii
^:...
/
Ophtilic •— —^i
>it!/i)to)ii<'.
I) link
jiii/otiiiiie
>Mv>i><.>iAX>r» First hmnchiitl
■ ■■''\ cU'ft.
„ Tliinl hritnchial
, iirrh.
Mimrlc liuii» to the
tongue.
I'vrirttrdium.
■'■'.Kxtii'iiiity /iliilc.
h'if/htli trunk
nij/Dtonii'.
I'^Ui. "iltl. Kinliryii III" liiccrtii viridis; cimihincd picture to show ("specially the
orijjiii III' llif iimsilis ul' tlic Imi^ruc, Alter (nniiiin. taken fnnii .1. Kull-
inamrs Lelnlmeli iler l",iit\viikeliiii;;sixeseliielite des Meiisclieii, .leiia. 1S!)S. S.
^!l(i. Fiji. Itllt. I
ij^roiips. In the s[)iniil cord it is believed that both sorts of (ll)r('S
are related to the coliimiia intermedialis or rej,Mon *4' the cornii
laterale, the motor fibres in idl ])robability arising tiiere, and the
sensory fibres terminating there.
ilerrick, in his study of the cerebral nerves of the bony fishes,
states that in the cerebral nerves these four comiioneiits jtre |)res-
ent, iinil in tuldition ii (ifth component, the so-called aciistico-
OlKH'PlNd AND CIIAININO TUUHTlIKlt OF NKlliONKS.
923
lateral. The somatic motor component, for example, is repre-
sented by the motor nerves of the eye muscles, the somatic
sensory or general cutaneous component by the general sensory
fibres of the nervus trigeminus and the nervus vagus. The
aws:::-
r.recM:
nVIIpt tinC
b.c.5.
I.hm.
Fig. iJOS. — A (liaf^ntiiniiiitic view of the scnsury ctiiiiiHUicuts nf tlic ci'i-clinil nerves
of Mciiidia. as seen t'nmi the lijilit side. Tlic dia^tnini is liascd iipim a pro-
ji'clidii 111' the t<'i(hi'al lu Tvcs ii|i(iii tlii' saKittil iilaiic inadc liy rccdiistnictioii
IVoiii serial sections. Tin' i;<iiiral i iiMneon;; I'linipmient is indit ute<l liy the
single cross-liateliinK tiu' rdninnmis ((Pinpinient liy donlile cross-liatcliint;
and tile aeiistie<i-lateral is drawn in lilack. ( After ('. .1. Ilerric k. ,1. Coinp.
Neui-dl.. (iranville. viil. viii. ISitS, ) h.i-.l to Ua-Ji, the live Inaneliial elel'ts ;
hr.ii..\. tlu' uaniilia id' the t'nur l>raniiiial rami of tlie vaKiis, tile lust one
(dntaininj; also the j^aniilion of the r. intestinalis : il.l.iiJ'I I. the dorsitl
lateral line Kanjjlion id' the seveiil h nerve: f.r.. faseienlus loinnninis ; (lits.fl.,
(iasserian fiimfjlioii : ijin.ii.i'l I. };enirnlate jiaiijjlion of thi' seventh nerve;
/.v. the f;losso-pharyn;;eal nerve and its <;anf;lion ; .hiii.il. the general laitil-
neous KanKlioii of tlie vagus nerve (.jngnlar g. id' Shore and Strong) : Inh.X,
the lo))Us vagi : )i./. the olfactory nerve ; ».//, the optic nerve; r.riil.iliiis.X,
ramus ciitaneiis dorsalis of the vagus; r.iiilisl.X. ramus intestinalis of the
vagus: i-.ldl.X. ramus lateralis of the vagus; i.aith.sii)). I', ramus ophthalmicus
superlieialis trigemini : /■.()/)//..s»/>. 17/. r.nnus ophthalmicus superlicialis faci-
alis: Co/., ramus oticus: r./ml.. ranms palatinus facialis: i.nrA'U. ramus
recurreus facialis : r.st.X, ranuis suiiratcmporalis vagi : i\\'lli>-t. ramus pre-
treinaticus facialis: si>.\'.l. tractus spinalis nervi trigemini: /,<(, the tidier-
enluni acustieUTu : I.hm. truncus hyomandihularis of the facial nerve: t.'nif,
infra-iirliital trunk, containing the r. mandiliularis V. the r. maxillaris V, and
the r. huccalis VII. together with comnmnis lilires : 17//, the eiglith nerve;
I'./.;/. 177, the ventiiil lateriil line ganglion of the seventh nervj'.
1'^ ■
II-
visceral motor component corrcsj)on(is to the motor fibres of the
other cerebral nerves, and these Hbres leave the bniin by tlorsal
roots to become distributed to the branchial musculature. The
924
THE NKliVOUS SYSTEM.
visconil sensory component as well us the visconil motor eom-
ponent is very largely developed, and, according to llerriek, is
represented by the communis system of the nervus vagus, nervua
glossopharyngeus, and nervus facialis. The libres of this com-
ponent terminate either directly or by mediation of the fasciculus
communis in the vagal lobe which corresponds to the nucleus
ah« ciiu'rea? of higher forms. 'J'he communis system of the head
itself ditfers from the correspomling visceral sensory system of the
trunk in that it receives fibres from the taste buds and from other
sense organs not belonging to the system of the lateral line, liy
the acustico-lateral system is meant the structure whicli receives
fibres from the ear and from the organs of tbo lateral line, but
no other fibres. These fibres in the bony fish terminate appar-
ently together in the tuberculum acusticum. The motor fibres for
the unstri])ed visceral musculature pertaining to the cerebral nerves
are, like those in the spinal nerves, very small, while those for the
striated visceral musculature of the branchial arches and for the
somatic eye muscles are large. The fibres of the acustico-lateral
system are of two sorts ; those from the organs of the lateral line
are usually large, while the auditory fibres are of medium size.
The general cutaneous fibres are usually of small size or of
medium size, while the visceral sensory system (or communis
system of the head) consists of very small fibres. In Fig. 51)2
is reproduced the diagram which accompanies llerrick's article,
aiul which illustrates the relations of the sensory com])onents
in the cerebi-al nerves of Menidia.
The various groups of motor neurones corresponding to the
Individual motor cerebral nerves may now be properly considered
somewhat more in detail.
1, Those the Axones of which belong to the N. Hypoglossus.
Those corresponding to the N. hypoglossus have their cells
of origin in the so-called nucleus N. hypoglossi. This consists of
a gray column some eighteen mm. long, from one to two mm.
broad, and about one mm. in thickness. It corresjjonds to the
continuation upward into the medulla oblongata of the medial
portion of the ventral column of gray matter of the spimil cord.
In its lower part it lies ventral to the central canal of the medulla
oblongata. Above, the column is thicker and is situated beneath
the fioor of the fourth ventricle adjacent to the sulcus rnedianus
on either side. It extends anteriorly as far as the region of the
. N
or com-
.•ri'ic'k, is
3, nervus
lis coni-
isciciilus
mick'us
the head
srn of the
jm otlier
inc. By
receives
line, but
e apjiar-
fibres for
ill nerves
3 for the
1 for the
o-luteral
enil lino
1 size.
ize or of
miinunis
Fig. r)'.)-Z
i article,
i])onents
f to the
nsidered
leir cells
insists of
wo mm.
3 to the
3 medial
al cord,
medidia
beneath
ledianiis
1 of the
Kid. 5!K5. — niiifjiiiiTi prcpiircil 1).v Miss F. S!il)iii IVdiii a scries of sections through
tlie liniiii of 11 nc\v-l)orii liiilic, showing Ilii' micici of the <'crc))nil nerves iiii<l
the area of exit ami of entriincc of the roots of tliecerchral nerves in Ihil iiro-
.jcclion. (/, line of hiteral ed^e of foiirlli ventricle : <l, it. il. il, fovea inferior ;
«'. fovea snperior; ;/, lateral snrface of rhoniheneephalon ; ///., area of exit of
N. ocnloniotorins : / I'., ana of exit of N. troehlearis ; I'., area of exit and en-
trance of N. trijieniinns ; 17., area of exit of N. alxlncens; 17/., area of exit of
N. facialis: 17//. ^ ci»/(. . area of entrance of \. cochlcie : 17//. i rev/ (/<.i, area
of entrance of \. vcstilinii : /.V. and .V., area of entrance of N. Khissopliaryii-
jiens el va^us; .\7.. area of exit of N. accessoriiis : A//., area of exit of N,
h,vpo}{lossus: Xii.ii.in., nncleus N. ocnio-niotorii : .V/(.//./r., miclciis N. troeh-
learis: .V/(.H. r.' //I./*. ', nucleus niotorius princeps N. triKcniini ; .V».;i. 17. , nu-
cleus N. atiilncentis : .\ii.ii. \'l I.. immMciis N. facialis ; Sii.n., nncleus and (ixu us;
Sh.u.c. nui'leusahi' cincrea" : Sn.ii.r.m., nucleus N. vestihuli niedialis : Sii.ii.r.s.,
nucleus N. vestihuli superior; Xii.ii.r.l.. nin-leus \, vestihuli later.ilis i Deilersi;
A'l/. (I.e. (/..nucleus N. cochlea' dorsal is : A'((.».r. r.. nucleus N. cochlea' vent rails ;
Xii.ii.Xfl., nucleus N. hypo^tlossi : /'.(/.»./., nulix descendens i inesencephalica|
N. triKeniini : li.il.n.r.. radix descendens N. vestihuli; .s'.;;.. suhslantia Kelati-
nosii ; T. mil., tractus solitarius : I'r.s.ii.l., tnu'tus spinalis N. tri};einini: I'riil.,
ventral horn cells. The nund)ers to the left of tin- dniwiiif; indicate approxi-
inatel.v the levels of the <'orrespondinji tran~vei"se sections represented hy
Fif,'s. isii.s to HI".
The plane of the sections IVoni wliich this diagram was made i.s not 'lite trans-
verse hut somewhat ohlique; the dorsal snrface of the inedulia has heeu
struck hy the knil'e more cerehralward than the ventral snrface, the an;;le.
formed hy the plaiu' id' the section with the longitudinal axis liein^ approxi-
niat<'l,v seventy decrees, as measured on the cerehral side. This accounts lor
tlie eviilent isli<;lit) displacement cerehralward of the structures in the ven-
tral portions of the sections as compared with those in the dorsiil i)ortions.
II
OHOUIMNU AND CllAININU TCXJKTIIKIl <)l'' NKrUONKS. <>.J5
Mi h
Fk;. r)il3.
I
I
fif,
4
Ml '<■
y2»)
TIIK NKKVOUS SYSTKM.
striii' incdiilhiroH. It is H('j)iir;ilc(l fi'ojii tlic Hour of the fourtli
voiilricU' by soiiio gray iniittcr wliicli t'orifsiioiid.s to tlio goiicnil
stnitiirii griseimi ceiitrak'. In tliia are u miinbrr of tinu wliiti;
tibros wliich give the opaque whitisli api)earaiice on the surface of
the trigoiuiMi X. livj)ogiiissi. posteriorly, as is seen from Fig. ")!).'),
tlie nucleus N. liypoglossi is overlapped by the niu'li'usahecinereu'.
The more or less spherical nuiss of small ganglion cells lying
ventral to the luicleus N. hypoglossi is the so-called snuiU-celled
liypoglossal nucleus of h'oUer. It probably, however, has no direct
connection with the N. hypoglossus. 'IMie group of snudl cells
lying just medial to the liyi)oglossal nucleus in its uj)j)er half
continues with a mass of cells running longitiulinally ; in the lloor
of the fourth ventricle is the so-called nucleus funiculi teretis.
On its lateral siiie and between it ami the nucleus ahc cinerea' is
situated an anterior grouj) of small nerve cells, the iiitdeo inter-
cahilo of Staderini.
The cells in the nucleus X. hypoglossi are typical motor cells.
Their axonos pass ventralward and slightly lateralward and —
])artly after perforating the medial accessory olive, and (;ven jjor-
tions of the nucleus cdivaris inferior, partly by passing between
the nucleus olivaris inferior and the medial accessory olive — arrive
on the surface of the medulla oblongata in the sulcus lateralis ven-
tralis, appearing in the form of from ten to fifteen lila radicularia.
A few libres may jiass from the nucleus of one side through the
raphe into the nerve of the opjjosite side; but this is disputed.
The libres are coarse and much branched, and. according to
van Gehuchten and Ramon y Cajal, may extend even as far as the
nucleus of the other side so as to form a definite protoplasmic
commissure.
The nucleus X. hypoglossi receives from its lateral and ventral
surfaces an enormous number of collaterals and terminals, part of
which are sensory, while part, in all proljability, represent fibrils
coming from axones higher uj) in the nervous system (possibly
fibres of the jiyramidal tract). The sensory fibres a])j)ear to
have their origin fron) the axones of cerebral sensory neurones
both of the first order and of the second order (Fig. 5114).
In the embryo the X. hypoglossus, like the spinal nerves, is
provided with a dorsal sensory root and sensory <?anglion, or occa-
sionally with dorsal sensory roots and sensory ganglia. We have
seen that the N. hyjioglossus corresponds aj)parently to at least
five neurotomes, since it innervates muscles derived from no less
CI I trill
Dart of
tihrils
Dssibly
'iir to
urones
•ves, is
|r occa-
have
It least
mo loss
(lUoriMXO AN'I) CIIAININO TCHSKTIIKIl 01" XKri{ONKS. »I27
than five niyotoino.s. Tims far, however, only two sensory ;riin-
g\'n\ and dorsal hypotjiossal roots liavo been observed in hijjher
animals (in the cat by I'. Martin); in man a siii<;le hypoj^hissal
ganglion (Kroriep) husoeeasionally been observed, but only rarely.
\W ,^
'! -r' ,1. u \
Fl(i. r>!U. 'rraiisviM'sc sotinii tlu'iiu;;li tlic mcdiiUii ((hloniriitii of it tikiu-^i' ;il
the level (if tile iiucleiis ((iniiiiissiiriilis. i Al'ler S. Wiinioli y (MJiil, HeitniK
/uin Stildimn der Mediillii < )lil(iiij;iilii. etc.. iiresler, Leipz.. ISlKi. S. IT, t"i«.
1:^.1 .1. nucleus ((iiuiiiissiiriilis ; II. iiileleiis N, liypofjlnssi ; ('. deeicsMtict
leimiisciinmi : It. Iriiiisveise seetiduut' Iriietiis s(ilit:iriiis ; /■'. central piilli I'nr
N. N. /.V : ((, cell id' imcleiis cdimiiissiiriilis : h. c, teniiiinil litres (d' N. v:i;,'iis
et N. t;l"'^^'i|diiiiynt;eiis ; il. coiiiiiiissure roitiied liy ciillateials cil' hypoglossal
liiudei ; ;;. ./. cnllaterals (il'seiisiiiy aximes ol'the secoiKl oitler lor the iiiK lelis
N. hy|)of{lossi.
The npper motor neurones brinp;in<; the nucleus nervi hypo-
glossi under the influence of the pallium will be described further
on. The nucleus N. hypoglossi is, of course, of especial clinical
interest on account of its cdiinectiiMi with disturbances of speech.
2. Those the Axones of which belong to the N. Accessorius.
The lower motor neurones corresponding to the X. accesso-
rius are usually described as being partly spinal, partly cerebral,
in origin.
lif
m\
J>2S
TIIK NKIIVOUS SYSTKM.
Kmhryoloj^inil Htiidics wurraiit the •■oiicliisidti tliiit orij,'iiiulIy
tljc iicrvii.s iicccrtsoriiiH is diMliiu;!!)' ii Kpiiml iutvc, its cerebral
(!oniieeti()ii8 beiii^' niiide only Hecondarily. 'I'liis is proved not
only by investiffationH on its nndeus of orij^'in inside the central
nervous system, i)iit also by tbe fact tlial it innervates muscles
which have their ori;^in in myotomes Ijclonj^'inj,' to the trunk.
Itndimentary j^anglia have Iteeii ol)served upon it by Chiarugi,
The 8o-uulk>d cerebral part of the N. ucccssorins in all ])roba-
bility belongs to the N. vugns.
Fimciculu* gracilis.
Fancicnlus cuiu'dhtn.
Suhsta iitia yela tin omi
SucIpus funiculi gracilit.
\\\\
N. accesmiriitii.
yuKcifulKn Hiiinocere-
hrllariH (lorsd latenilis.
Ctiiialiii itiitriiliii. "
Fasciculnn rciilri) tdtcnilis
proiiriiis.
',•^41
' PeoisnaUii i^yra m itliiiii .
Via. Jilts. ^'rnmsvcrsc sfdioii thrmiKli "iic side (if cfiilrnl nervous s.vst«'iii of iicw-
liorii IimIic at Jiiiiclioii of jimi's ci rvicalis iiicdullii' spinalis willi the niciiulla
oliloiifiata, showing tlir N. acfcssoriiis. i WiimTt-l'al lucjtaration liy Dr. .lolni
llfwclson. ilrawiu}; l>,v A. Karsttd. '
In the spinal cord the cell bodies of the neurones pertaining
to the N. accessorius are situated in the lateral horn, where they
form a part of the so-crdled oolumna intermedio-laternlis. The
nucleus is usually described as beginning at the level of origin of
the fifth cervical nerve, and I'Xtending as far as the junction of
the lower with the middle third of the nucleus olivaris inferior
of the oblongata. The niedullated axones arising from these cell
bodies pass lateralward with a sharp bend to find their exit from
the sulcus lateralis of the cervical cord (Fig. .">*.(.")). Von Kolliker
distinguishes .sharply between the spinal })ortion of the N. acces-
sorius and the cerebral portion. All those root bundles finding
exit ventral from the tractus spinalis nervi trigemini he classes
(iltollMNiJ AND C11AININ(J T()(JKTIIKU OF NKIMCONKS. <»2l»
witli the Hpiniil |mrt, hut all root biuitllcs sitiiutt'<l hij,'lu'r up or
imsHiii^^ tlirou^'li llii' tnicUiH spinalis iicrvi tri;,'t'iiiiiii lie spcuks of
us bring acci'ssory to llu' niTviis vagus.
3. Those the Axones of which belong to the N. Vagui and N. Olossopharyngeui.
'I'lif lower motor neurones eorresponding to tlie N. \.\(iis
and the N. tii,(»s.s()i'iiAUVN(ii:is possess axones which arise from
thu (!ell bodies situated in the nucleus ambiguus and possibly in
other masses of gray matter in the medulla ol)longata. 'I'liis
nucleus ambiguus lies dorsalward from the nucK'Us olivaris aiuics-
sorius dorsalis, nuMlial to the tractus spinalis nervi trigemini, in
the formatio reticularis. It is ditliciill to make out in ordinary
Weigort preparations, but is heautifidly demonstrable in Nissl
preparations, where it is seen to consist of a group of typical
inidtipolar stichochrome motor colls. The nucleus ambiguus
extends a littkf more anteriorly than does the ii;:c!c'.is nervi
hypoglo.ssi. The axones from the cells situated in the nucleus
do not form a compact bundle, but pass out as separate fibres
from the cells in a dorsal direction in order to reach the plane in
which are situated the entering axones of the peripheral .sensory
neurones of the .\. vagus and tjie N. glossopharyngous. 'IMien
they turn sharply lateralward and ventralward to pass out of the
medulla (;l)longata at the sulcus lateralis dorsalis in comm<tn
with the entering sen.sory portions of the nerve. In the nucleus
ambiguus termiiuite a number of line mccluUatcd axones and
collaterals which correspond to (1) fibres from the ccrcl)ral sen-
sory neurones and {'i) libres from niotor neurones wliich throw
the nucleus ambiguus under the inHuence of higher centres.
The nucleus ami)iguus corresponds to the lateral horn of the
sj)inal cord. The N. vagus and N. glossopharyngeus are typical
branchial arch nerves, but their exact neurotome relations are
still obscure.
4. These the Axones of which belong to the N. Facialis.
The lower nu)tor neurones corresponding to the N. I'aciali.s
have their cells of origin in the nucleus nervi facialis, which is
situated in the pars dorsalis ])ontis just anterior to the junction
of the medulla oblongata with the pons. This nucleus corre-
sponds to the colunina intermedio-lateralis of the spinal cord. It
is essentially the nerve of the hyoid arch — the same arch which
in the embryo yields a part of the hyoid bone, the styloid jjrocess,
1
V' '
•('
i
'<
9;{(i
TIIK NKKVOUS SVSTKM.
I! 1
t ■
till' stylohyoid iiiuscU', tli(> posterior belly of the (li«riistri(' tmiseic,
the small nuiscles of the ear, the whole of the imiseles of the
fiiee, the phitysriia, etc. An iiiiiisual interest iiertaiiis to the neu-
rones corros])on(linj; to the N. faciulis, since it is they that govern
the tnnscles of facial expression. 'I'lio cell bodies of the ntn-
rones here concerned are typit'al nudtipolar stichochroine motor
cells, easily recognizable as a larj^e group (I''ig. 5!m;) in tlu' format lo
reticularis medial from the tractus spiiudis nervi trigemini and
dorsal from the corpus trapezoideum. 'I'he medullated axone.s
from the cells of this nucleus pass as separate lil)res (not in a
compact bundle) (k)rsul\vard and somewhat medialward (/)(ti\s
pri/iKf) towanl the lloor of the fourth ventricle. They then
bend and run antoriorly along the lloor of the fourth ventricle
dorsal and medial to the nucleus nervi abduceiitis, and then
again turn latci'ahvard to plunge ventro-laterally in the form of a
compact bundle (/^a/'.s- srcinida) to their place of exit from the
rhombencephalon, passing between the nuideus olivaris superior
and the tractus spinalis lu'rvi trigemini. The double bciul be-
neath the floor of the fourth vcn'ricle is known as the (jcini
nvri'i faciaUs.
It would ajipear that a certain luunber of the root fibres of
the nervus facialis of each side have their origin in the nucleus
nervi facialis of the opposite side, the decussation taking place in
the raphe dorsal to the fasciculus longitudinalis nu'dialis (Sticila,
Obersteiner, Cramer). In the nucleus nervi facialis tcrmiiuitc
many axones ami collaterals from cerebral sensory neurones of
the first and probably of higher orders, and also axoru's and col-
laterals, throwing the nucleus niuler the iullucnci' of motor lu'u-
rones, the cell bodies of which are situated higher up in the cen-
tral nervous system.
It is customary to sjieak of a " lower facial" and an "upper
facial" nerve. The so-called " upper facial " is the part which
innervates the .>[. frojitalis and the ^^. orbicularis ocnli; the
"lower facial" innervates all the other muscles which nveive
their Tierve supply from the X. facialis. The principal litera-
ture on this topic is referred to in an article by Hregmann.* In
certain paralyses the muscles innervated by the "lower facial"
may be paralyzed, those innervated by the "upper facial" being
11 I
* I?n\i;niiuHi, Ij. K. IVImm- Pipiofjiti fiU'iidis. NViirol. (Viitrnlb., lioipz..
B(l, XV (181l(b, S. a4e-',MH.
:
GKOUl'INCl AND ClIAIiNlNU TO(il':TIII<:U OF NEUliUNES. <jyi
t .. i
7{\
I
li.1
932
TFfK NKRVOUS SYSTP^M.
scarcely, if at all, airected (so-called supranuclear paralysis). In
other forms of paralysis all of the muscles innervated by the N.
facialis may be equally paralyzed — as, for example, from a lesion
involving,' the N. facialis at its exit from the rhombencephalon.
All attem])ts made to locate separate grou})s of lower motor
neurones corresponding to the " ui)i)er facuil " and " lower facial "
have thus far been unsuccessful, though, as we shall see, in the
cerebral cortex these two functional grouj)s are separately repre-
sented.
5. Those the Azones of which belong to the N, Abducens.
The lower motor neurones corresponding to the N. ahducens
have their cell bodies and dendrites situated in the nucleus nervi
abducentis in the pars dorsalis pontis. This nucleus, more or
less spherical in shape, lies close beneath the floor of the fourth
ventricle, being partly surrounded by the genu nervi facialis.
The cells and their dendrites have all the characteristics which
we have seen so often in other groups of lower motor neurones.
The medullated axones pass ventralward and slightly spinal-
ward, plunging through the formatio reticularis and corpus
trapezoideum medial to the nucleus olivaris superior. Then
})lunging farther through the pars basilaris ])ontis, they make
tlieir exit from the rliombence])halon just a little anterior to the
junction of the medulla oblongata ami ])ons in the form of from
fifteen to eighteen fila radicularia. In leaving the nucleus the
axones go, in the main, from its dorso-medial border. Accord-
ing to van (Jeluu'hten, who has studied the chick thoroughlv
with (iolgi's method, a certain number of fibres of the M. abdu-
cens on each side arise from cells close to the nucleus nervi
facialis. The axones bend around and join the main bundles of
fibres from the principal nucleu.'^. This accessory nuiss of cells,
whicli has also been seen by Lugaro, is referred to by van
CJehuchten as the "ventral nucleus of the sixth nerve."
In the nucleus nervi abducentis terminate axones and col-
laterals from various sources : (I) from the peri]>heral cerebral
sensory neurones ; ("2) from the cerebral motor paths ; (:{) from
the nucleus olivaris superior (cf. auditory neurones of the second
and higher orders) ; and, especially, (4) from the fasciculus longi-
tudinalis medinlis. My means of the collaterals from the latter
bundle the nucleus nervi abducentis is in all p^robability brought
under the intluence of the superior coUiculus of the cor])ora
OlioUIMNG AND ('11AININ(} TOGKTIIKR OF NKruoNKS. 933
quii(]rif?(Mniiiii, and the imiorvation of the rectus lateralis iiiuscle
of the eye is such as to lead to movements co-ordinated with
those of the otiier eye muscles (es^iecially the rectus medialis)
which are innervated by the nervus oculomotorius and the ner-
vus trochlearis.
m
'0\-
t'om
lond
In-ii-
Itter
™srht
k)ora
6. Those the Axones of which belong to the N. Trigeminus.
The lower motor neurones corresponding.^ to the motor part
of the X. T UK) KM IN us may be divided into two groups: (1)
those having their cell bodies of origin in the nucleus motoriu3
princeps nervi trigemini, and {'i) those having their cell bodies
of origin in the nuclei niotorii minores nervi trigemini.
The nucleus motorius princeps nervi trigemini {noyau mttstica-
teur oi the French authors) is situated in the pars dorsalis poutis
just a little anterior to the nucleus nervi facialis aiul the nucleus
nervi abducentis (Kig. ."iilj). It lies nu'dial to the main mass of
a.xones of the peripheral sensory neurones of the trigeminus as
they plunge into the pars dorsalis pontis. I'he nucleus is a large
one, and in Xissl i)reparations it is seen, like the other motor
nuclei of the rhombence|ihal()n aiul of the spinal cord, to contain
a large tiumber of typical multipolar stichochronie motor cells.
The medullated axones of these cells, joined by the medullated
axones of the nuclei motorii minores nervi trigemini, to be pres-
ently described, form the motor portion of the nervus trigeminus
(Fig. r)!»8). The motor root fibres easily distinguishable from the
entering sensory axones pa.ss obli(piely out of the pons to become
distributed entirely through the nervus mandibularis (Fig. ")'.•!!),
or third portion of the nervus trigeminus, to the muscles of
mastication. A certain number of axones from the cells of the
dorsal nu)tor nucleus of one side pass to the motor portion of
the nervus trigeminus of the opposite side (Obersteiner, Kd-
inger, Bruce), the decussation taking place in the dorsal part
of the pars dor.salis pontis.
In among the cell boilies and dendrites of the jtrincipal mo-
tor nucleus of the nervus trigeminus terminate many axones and
collaterals (1) from the cerebral sensory neurones of the first
and of higher orders, and (2) doubtless from the upjx-r motor
neurones.
The nuclei motorii minores nervi trigemini contain the cell
bodies and dendrites of tiie neurones, the axones of which form
the radix desceudens (mesencephalica) nervi trigemini. The
I'll
^m ^
934
THK NERVOUS SYSTEM.
GROUPING AND CHAINING TOGETHElt OF NKl'UONHS. 935
cells which form these nuclei are vesiculiir rutlier than stellate ;
their dendrites are rudimentary ( liUgaro, Kamon y Cajal). Their
axones descend, giving olf numy collaterals on the way, some of
which always enter the nucleus motorius princeps nervi trigemini.
The cells, as described by Ramon y Cajal, form a column which,
descending from the region of the corpora (|uadrigemina, passes
obliquely over the brachium conjunctivum, growing larger in size
as the nucleus princeps is approached. The axones of these cells
are of large calibre at their origin, and, gradually growing more
delicate, run along with those of other cells in a curved longi-
lidilijf iU-menilen.i .V. rintihitli.
«
firachiiiiii con
Junctivum
Nitcici iiiiiton'i
iiiiiKirci X.
trigi'Diini
Niiclcit.i )iio-
toriiis fin'n-
ci'ps A. tri-
gemini.
.\\icl<'tisfnii icidi urdcilis.
FiiiifiriilHS
yracilis.
S tri<n'iiii>iuii
( portii) iiiniiir)
Fd.fcicuhi.i lilt ft alls
/
Tractus .ii)intilis S. triijemini.
N. trigeminus '
(poriio ni(ijof).
.Y. ivsfilnili.
.V. ;//()S,s( )/ ill ft ri/n geMS.
Fig. .")!)H.— Sagittal section tlinniKli rlKiniliciKcplialoii of liiiiiiaii t'o'tiis. (.\l'tc'r
A. \\iwi>. Illustrations of -Mid- and lliiiil-Brain, lidin., IHit^. )
tudinal bundle, which increases in volume as it descends (radix
descendens). Before the axones of the descending roots reach
the nucleus princeps they undergo a i)lexiform arrangement,
whereby they are distributed between groups of spherical cells,
and finally the bundles of the descending root become mixed up
with the cells of the nucleus princeps (Fig. <iOO). Kamon y Cajal
states that the extremely complex plexus of fibrils among the
cells of the nucleus princeps arises almost exclusively from the
terminals of collaterals given off by the fibres of the descending
root. He suggests that these collaterals may be of the greatest
^1^ physiologicid importance, and suggests that the absolute coinci-
^ dence in point- of time of the movements of the masticatory mus-
cles might be explained by the view that the voluntary excitation
received by the nuclei minores is transferred by means of these
''. il
!
930
TlIK NKRVOl'S SYSTK.M.
collatonvls to the iiorve cells of these nueh'i iis well as of the
nucleus princcps. Ho tliiiiks that these and other examples make
it seem likely that the collaterals of the motor roots, ami ju-rhapa
those of every axone, have the function of distributing; the exci-
tation received from a sin<;le cell, or from a small number of
cells, amonjif all the cells of the same nucleus or in a j^roup of
similar cell elements situated in dilferent regions of the gray
\u. III. III. n. V,
\ii.iH.j)r.H. r.
Ti: s/>. n. V.
Fl(i. 5ili(. — Sclifnic sliowiii}; the motor and sensory ncin'oiifs, tlic axoin'sol" wliifh
ontcr into the I'orination of the N. trif;cniinus. ( After A. van ( ichuclitcii,
Anatoinie (les systenie nervenx de I'lioniint', liouvain, l.SitT. p. 'y\\\, Kij;. 3S4.)
ff . N. <>'.. f;anjilion semilnnare (Jasseri ; .V". m. iii. ii. I'., nuclei niotorii niinores
nervi trifji'mini ; .\ii. in. jir. ii. I'., inieleus motoriiis iirine<'ps neivi triKeniini ;
Hull, ilcnr. m<'.i. (I. I'., radix deseendens [niesencepiialica] nervi trif;eniiiii ; 7V.
sji. II. r., tnietus spinalis nervi triKeniini.
substance. Accordingly, the nervous excitation, feeble in the be-
ginning as it comes out from one cell, would, in proportion to the
number of neurones intercalated, grow and atttiin to its greatest
effect at the beginning of the exit of the motor root. If the
stimiUus of the voluntary excitation is transferred exclusively to
one muscle or one group of muscle bundles, then the collaterals
II
II.
3St
.he
to
uls
Ciiwllll.
r
Fl<i. 000. — I'nintal section tliniiisli tlif Imiin stem of a I'd'tal inoiisc. lAftciS.
IJjinioii y < iijiil. Mcitraf; /.uiii Studiiiin dcr Medulla Olilmifiata, clc, UrcsltT,
licij)/,., lHil(). S. 1.'), Kif;. t. I .1. luiclfiis iiiiitiiriiis in'iiK-tps N. trifjciiiiiii ; li,
nulix iiii)t<iriiis N. tri;;ciiiini : ('. lower piirlioii o'' nuclei inotorii ininores N.
triKcniini ; />. upper portion ot' nuclei uiincu-es near the I'ourtli ventricle (/v);
/•". railix sensorius N. ti'itreniiui ; <!. In'aciiiuni conjuuctivuui : //. Iiundle of
descendiuf; axones IVoin liracliiuiu conjnuetivuni : «. cells of nucleus niot<piius
pi'inccps: ti. sensory collaterals tliroUKli the sulistantiii jielatiuosi of tin;
trigeminus; c. axoue ol' sensory trineinin.il neurone of the second order: <l,
sensory cidlaterals which appear to enter the nucleus niotoi'ius princcps;/,
line collaterals from llw axones of the nuclei minorcs ; /'. pear-shaped cell ;
.;'. cell without dendrites; c, coarse lindis of hiftircation of the axones in the
nnlix deseendens mesencephaliea ' N. ti'iueniini with hraneh inside the
nuch'us motorius princcps.
* i
938
THE NKItVOUS SYSTKM.
of the motor roots are oitlier only inodenitely developed or en-
tirely absent, as is seen in the nucleus nervi hypoglossi and in the
nucleus nervi oculoniotorii. In these cases, acc()rdin<,' to lianion
y Cajal, the number of cells associated witii the motor impulse
will depend upon the number of lil)re8 of the pyramidal tract
received by the motor nucleus, or perhaps upon the distribution
of the end branchings of such fibres.
Merkel's view that the radix desceiulons nervi trigemini rej)-
rescnts a trophic root has not been confirmed by other investi-
gators.
7. Those the Axones of which belong to the N. Trochlearis.
The lower motor neurones, corrcsjmniling to the M. Tuocil-
LEAKis, or fourth cerebral nerve, may next be described. The
cell bodies and dendrites of these neurones form the so-called
nucleus nervi trochlearis, which is to be seen in sections i)ass-
ing through the isthmus rhombencephali and inferior colliculus
(Fig. GOl).
The cells are typical multipolar stichochrome motor cells, and
the nucleus forms a spherical nodule, which lies ventral to the
aqueduct of Sylvius in a trough on the dorsal surface of the fas-
ciculus longitudinalis medialis, somewhat posterior to the spinal
extremity of the nucleus nervi oculo-motorii. In Weigert prepa-
rations many fine medullated axones can be seen passing from
the region of the fasciculus longitudinalis medialis into the nu-
cleus nervi trochlearis. Through these, in all probability, the
activities of the nucleus nervi trochlearis are co-ordinated with
those of the other eye-muscle nuclei. It is likely that the nucleus
also receives axones and collaterals from peripheral cerebral sen-
sory neurones and from neurones which throw this nucleus under
t^'" inttuenoe of the pallium.
The medullated axones from the cells of the nucleus nervi
trochlearis pass out of the nucleus mainly from its dorsal and
lateral surfaces. They curve lateralward and donsalward through
thp stratum griseum centralc until they reach the level of the
rac. : descendens nervi trigemini, when they make a tolerably
sharp turn spinalward and run for a short distance longitudinally
backward, so that in transverse section the root bundle, or some-
times two or three root bundles, are met with in cross section on
■each side. Having reached the level of the velum medullare ante-
tIus, the fibres turn sliarply medial ward and dorsalward to undergo
'.'i*'
Fki. (M)1. — M(iri/(iiit;il scclicni tliniiitih the incdiillii. pniis, anil niiill>i'Miii of a new
liorii Italic. \\'('i"crl-l'al staiiiii
Lrvi'l III' iiiU'lriis iirrvi iiriiliiiiintnrii ami
mirli'iis iiirvi triichli iiris. iSeries iii. siTiimi No. I(H». ' .li/. cc;-., ai|iiiiliirtiis
cffi'liri ; /]
liri ; r. Ill lilt..
f. mill.
)•
ai'lililiii riiii.jiinrlivillri ; r./i., ciiiiiliilsMira iiiistcnni'
niiimiissmc liclwicii |{i rlili rrw's iiiirlii iiC llic two sii!
<:
ciii'ims ri'slil'iiiiiif ; I'.l.ui.. fasriiiiliis lniii.'iliiiliiialis iiiiilia
I'.c. Ill I'.i.. (ilirrs
rriiiii rasriciiliis iiiiiiiiliis to luriiialid rclinilaris : i'ih, mr. nil. Mn-.v aniiala'
iriliTiui' : /■'. IK., fasf. riiiiialiis ; /•'.!■.<(.. t'lirinaliu nliriilaris allia ; Mnl. I'., raiiix
.V. ifsl.. r.iilix N. vistili-
iiiiitiiriiis \. iii;;i'iiiiMi : .V. 17.. lailix \. aluliuriil
nil :
.V. 17/,
niilix N. facialis, pars sccmida ; y.lXonilX. railici
f;liis,sii|(iiar.viiKci ct \;vX\ : .\..\'ll. railix N. Ii.v|iiij;li)ssi ; .Vh.c.
cciilralis superior, pars incilialis; .\i
iiiiclciis
/.
lateralis ; .\ii.l.l.. iiiiclciis Icimiisci lateralis ; .\ii.l.
iiiclciis centralis superiiir, pai>
Sii.ii.lll.. iiiiilciis N. iieiildiiiotiirii ; .\i
s.. nucleus lateralis superiur
11'.. niielciis N. Iriiclilearis ; /,.
leimii.sciis superiur: .V/i./.i/.. nucleus I'uniculi Kraeilis; Sii.ii.iw.. niielcus N.
I'll!
ea- vent rails
w(.;(
17/, nucleus N. I'acialis; N,i/.. sulislanlia tjelatinosi
St.i.l.. stratum intendivare leiiinisci : Sd.!'., radix seiisnrius N. trijieiiiini ;
W.f/.c,. stratliln Ki'iseuiu I'eiitrale; >'i»/). i/i/.. sulistantia ;(elatiliiisa near en-
trance of .seiisnr.v part iif N. triKciuinus; 7V. .<.»./., traclus spinalis N. triKciii-
ini ; 'I'r.fr.iiii. !>.. {rml from Driters' nucleus to the spinal coril. i I 'repar.it ion
liy Dr. .Iiilin llewetson. ■
GKori'lNO AND ('1IAIMN(! T(»(iKTIIKU OF NKIIJONKS. <.(;{«>
t X NuiSi
■«1
H
•<
a
'^.
c
C
•<
n9
•J
D
Q
u
Hu.n.cv.
Tr.fr.nuJ).
•F.c.toF.r
•9-
sHw
Ficj. COl.
If
I
^ i
5>4()
TIIH NHIlVors SYSTKM.
i
(lecuasiitioii iti tlid siil)stuiK'(' of the vcltini ( l-'i;,'. <i<»'i). It is bclicvcMl
tliut this (it'i'iissiitio iicrvoniin troclilcuriiini is cntiipltftis uiitl that
no llhri's t-ntor tho norviis trochlnaris from tlio imcltMis of the sumo
side. Imjiii'diiitt'ly uftor the docfussiition tho root l)uiidh'S iiiako
their exit from the dorsal surfaci- of the nervous system at I iio
F[<r. (il)2. Tniiisvcrsc scrtioii tliroiiKli istliiims rli(iiiil)('nf('i)iiiili "f iii'Whnrn
I)!i1h'. ' WciKcrt-l'iil. scries ii. scctiiiii Nd. 2tiH. ) lir.vinij., Iirachiuiii cdii-
Juiictiviiiii : r.i'., follicnliis iiitVriiir : 7. mirlciis (Ifscrilicd by Wcstptml iis
pnilialil.v coiici'mcd ill llic ciriKiTi nf tlif N. trociilfiiris ; /•'././».. t'nsciciihis
' >ii!'itiiiiiiiiilis incdialis; /■'./'(/., fasciculi Idiiniliuliiialcs [pyrainidalcs]; /,./..
lisciis lateralis: /..hi.. Iciimiscus incdialis: .V. /!'., dccnssitin iicrvoniiii
;dcariiiin : .V. I'., \. trifjcmiiiiis : S'lt.l.l.. nucleus leninisci lateralis;
II. r. I., nucleus retii'ularis tcfiincnti poutis ; It.il. I'., radix desceiideus [niescn-
.eplialica] iiervi tritiemini. 1 rreparation l)y Dr. .Iidiu Ilcwctsiin. 1
lateral border of the velum modullare anterius, lateral from the
freniilmn veli mt'didlaris aiiterioris, clo.><e behind the lamina (|uad-
rigemina. Tliere is often asymmetry of the root bundles on the
two sides; whereas the nerve of one side may go out in the form
of a compact bundle, the root fibres on the other side may form
two or more well-separated bundles (fila radicularia). Tliese bun-a|^
dies, however, unite almost immediately to form a common nerve ^P
trunk. The nervus trochlearis passes into the j)orus trochlearis
of the dura mater, runs through a small dural canal alongside of
,'!'''l
l^L
CiUnl l'IN(i ANI> CIIAININMJ T<»(iKTIIi;U OF NKlUuNHS. jm
the M. opIitliiiliiiicuH to tlie ilHHtim orbituliH Hiipcrior. lluvitig
iirrivi'cl ill tlin orhit, it passes ikmoss the origin of tlu' M. levator
])ulpel)ra' superioris to the M. ol)h(pius oeiili superior, into wiiidi
it enters in order to itmervute it. It is estiinuled tliat ilk the N.
trochU'uris there are bomic twelve iiundrod nerve libres.
8. Thoie the Azonei of which belong to the N. Ooulomotoriui.
The lower motor neurones corresponding to the N. o( iLo-
MOTOims, or third eerebnd nerve, jjOHsess cell bodies and den-
drites wliicdi are situated in the nucleus nervi ocidoin(»torii. 'i'his
nucleus is located in the mesencephalon. In sections taken
througlj the pedunculus cerebri it is seen to occupy a position
in the tegmentum ventral to the aqueductus cerebri and to the
stratum griseum ticntrale which lies beneath the acpieduct. It
ijt.alb.p.
Nu.n.m.
Fit! fiOU — Tnitisvcrsc section tliroiiKli iiics('iic<iiliiilciii, ciilliciili siiiicriorrs of cor-
"i)..r!i (|ii;ulriK.iiiiiiii iiiKl ccnliiiil iic.liiii.lc i.f ii(wl)oni I.mIi.' . \V.i;zi rt-l'iil,
scrit's ii si'i'timi No. :is». ) . I7. <•(•;•.. !i<iiif(lu(Iii> ccn^ln-i ; r»//.v»//).. cnllKulus
superior: />.r, (le<Mlssiiti<i tcKmelili <iorsiilis ■ fniitiiiiii'iiriiiH' llinihfiihiii-.niiii nt
Mi'Viiert)- /•'/.//(., fiiseiciiliis loimit'Kliiialis iiiediiilis : /•'./'//., Iiiseieiili pyrii-
iiiii'lules in the liiisis pediuK iili ; /•'./■. .V ). liisriculus retrotlexiis Meyneili;
[..III., leniliiseus inediiilis: Sn.F.l.m.. nuelelis liiseienii loii«itu<lin;ilis niedi-
uiisiiV iinelens eoniinissurie postelioris ■nhi-i-fi- (h-nliiiiitiliiriiinkfni of I);il kselie-
wilscli': Sii.ii.lll. nucleus N. oeuloinolorii : .V".
:# I •
iiiher; X.lll.
X " oc'uloniotorius: >7. <(/'(./).. stnitum iilliuni prolunduin : st.iir.i:. strMliiMi
Kriseuin centi-iile: s.u.. sulistiintiii ui«i'ii : a, re«ion of I'leclisi};'s I'lisiisrlilriff ;
p. tcniporo-oc.ipitiil tnict to pons: y. frontal tniet from pallium to pons.
I i'reparation by Dr. .lolin llevvetsou. '
is situated just dorsal to tlie fasciculus longitudinalis medialis
on each side (Fig. (lo;?). Since the aqueductus cerebri is here di-
t
!t|;
rilK NKI{V(»l'S SYSTKM.
I
rt'c'tftl ol»lit|iu'lv, till' loiijj; axis III' tlic luu'lriis n(>rvi nculdiiKilorii is
iiicliiicil III ail aii<::l(> to a line di'awti {larallcl to tlic long axis of
till' fourth M'litrii'lc (riiir sii/mt).
Tlic axoiifs of cacli iicrviis oiMiloiiiotoriiis arisi' mainly from
tlu' Miiclcus of the same sido Itiit partly from tlio iiiu'li'iis of the
opposite side; that is to say, thciv is a partial tlociissation of the
root librt's. 'This dccussalio lu'rvormii ociilomotorioriim ('dii-
(•(•nis mainly the posterior or distal (spinal) third of the niicleiis.
'riiiMH' is hut little, if any, decussation of the axoiies arisin<^ from
• cell hodit'S situated in the anterior or proximal (cerehral)
two thirds of the nucleus.
The nuclei of the N. oculomotorii are very complex, consist-
iiifi; of numerous cell groups; and although t hey have lieen sludii'd
Ity many al>li> invest ii^ators, notahly hy |)uval and [.ahorde,*
Spit/.ka,f Slarr,]; von (iuddeii," l'erlia,|| Westphal,'"' iMliiiger.^
van (iehucht(>ii,| t)hersteiner,| von K(>lliker,| and Mernheimer,**
we are still fai' fioni possessiii;,' an adiMpiate and satisfaclorv
kiiowledjje conceruiui; their various parts. That tlu'y should he
anatomically complex is not surprising when one rememhers that
the \. oculomotorius innervates ;: relativelv larire numher nf
T
* Duval, M., c'l .1. \ . hiilionlc. !•(• I'iiiiiciviU imi dcs iiiiiu\ cmu'iiIs iissuciis
(Ics fjfldlu's ociilaii'i's ; I'liiiics iraiialiMiiii' el di' [iliysioldj^li' fxpcriiiiciiliili'.
.lour, (if ruiial. I'l tlf la |>livsi.ii.. Par., I. \vi (I.SS(I). |.p. nCi S!t.
f Spit/ka, K. ('. 'I'lic 0(iil()-mi)liir Cciil res an<l llicir ( 'o-i ni I i nature, .lour.
ef NiTV. hikI .M.'llt. Dls., N. \'., v,.l. XV (IMHS). pp. .|t;t i;!-'.
t Starr, M. A. Oplilli.'iliiKipicu'ia I'Alcriia Partialis. .Idiir. of Ncrv. and
MtMiI. Dis.. N. ^■., \ol. w (ISSSi, pp. lldl nid.
" von (liiddcu. (ii'sanuiicllc .Mihandl., Wii'shadcii (IMSit),
I I'l'rli.'i. I>ii' .Xnaloiiiic ili-s ( Iculomoloriiisci'iil nuns liciiii Mciisclicu.
Arch. f. Ophlii., I,i'ip/.., lid. xxxv. .Vhlli. I (ISS!»). .S. 2S7 ;{()S.
'^ Wesljiliid, ( '. I'fld'r dii" cln'oiiisclif proj^n'ssivc liiiliiiuiii^' drr Aiiuvn
inuskchi. I'lilrr MiMiiU/iuit,' dci' von (!. Wcstpiial liinlcrlassfni'ii liilcr
siirlimi,t,'i'n, licioln'ili'l luid lii'raiisf^cp'lu'ii voii l). Sicmcrliui;. Siippl. Ud.,
Arrh. f. I'sych. ii. Nrrvrnkr., Him!., M. x\ii (ISitl). S. I 'J(»(».
^ l';diiif,'i'r. \\'v\. ilcr ei'iilral. I Iiriiin'r\ciilia!iii('ii. .\rcli. f. I'sycliial.
u. Ncrv.-nkr.. IJd. xvi (1^85).
^ van (icinicliten. Me rori^'ini' dii ih'iT <M'uloiiiolnn' roiiiiiiiin. Kidl. dc
I'Ae. ro\. di' Kcl.tf. (IS!»-J).
I Olierslciin-r. Aii/.'if,'. .1. k. k. (I.'s.dlscli. d. Acr/I.' in Wi.Mi (IHSO).
J von KiUiikt-r, A. I'dn'r <I(mi rrs|iriiiif; ilcs (Iculiunotorins lu-im Mcn-
srhcn. Sil/nnicsl). d. pliys.-nnd. (I.'s.dlscli. zn Wllr/li. (ISICJ). S. IIS I'.'O.
*♦ Ucrnlii'iincr, S. Has Wnr/cljit'bii'l ik'sOcidonioturius lu'ini Monsclii'ii.
H\o. Wi.'sl.ad.-n (1H!»I). pp. I S(t.
y
lA
(iU(>riMN(i AND CIlAIMNli KXJKTIIKK oK NKlKoNKS. <)\:\
luusch's, iiiiiitoMiii'iiUy mul plivsioloi^icHlly inoro or less iiuli'-
|H'ii(li'iil III" t>iii> iiiiol.lu'r, mill n>fiills I'lirtlu'r lliat tlicsf iiuisclos,
hotli iiisiilt' iiiul oiitsitlc till' t'Vt'l)all, an' co-oniiiuittMl in tlu> iiioHt
(Ifliralf wav willi nnc aiiollicr aiul with tlif iiuisi'li's iimcrvalftl
l>v otluT groups tit' li)\v(>r motor in'iiroiu-s (M. ol)li(|mis suiu-rior,
M. reel us lateralis, Mm. capitis ct colli).
it will he coiivciiiciit, owiui;' to the cxislciicc of a miclciis
impar, to ilcscriltc the nuclei of the t wo sides to<.;'et her. in the
newhoni h;ilie there can he vcrv distiiH-lly nunle out a larj^o
lateral nucleus on each side and a niu-lens impar in the middle
line. The niudeus impar does not extend <piite as far either
unteriorlv or posteriorly as do the lateral masses. \\ ith the hi<jh
powt r ol" the microscope, cells ciin he niiide out coiiucctini^ the
nucleus impar (except at the posterior and dorsal extremity) with
the lateral nncleus on its ventral aspect on each side. The
lateral mas.ses of the Iwo sides are mort> widi'ly separati'd I'rom
one another and nu>re independent at ihe postero-dorsal ex-
tremitv of the nucleus than at tiie anterior ventral extremity;
in fact, in the latter region the two lateral uui.sses fuse and form
a .solid mass of m-rve cells occupyiufj^ the miildK« line and a reii'ioii
just, lateral from this on each side. These appcaraiu'es are well
shown in a reconstruction made hy !•'. Snhin in the aiiatomiciil
lahoratory in Maltinuire.
The nuclei of the two sides in three dimensions looked at
from the dorso-anlerior surface of the reconstruction are of tho
shape of an arrow with its apex pnintim;' ventralwanl and an-
teriorly, its hase pointinjj dorsalward ami posteriorly ; or, on
account of the hollowed-out appearance, it may he said to re-
.semhle the anterior half of a canoe alonj;- the floor of which, from
the how to till" middle, projt>cls a thick vertical liar —the nucleus
impar. hooked at from the viMilro-poslerior aspect, the surfaco
is seen to he convex and toleralily uniform, except at the postt>ro-
(lorsiil extremity, \vln>re the nucleus impar is separated hy a nar-
row chink on (>acl> sidt> from the lateral nuisses of nerve cells.
.\ very elaliorate desci'iption has heen «:;iven hy i'erlia (l''i,^.
(iOl). This author ilescrihes a numher of <,'roups of m-rve cells
which he .says he makes out distinctly, lie divides the masses
-into ii superior <jfroup and an inferior iiroiip. The inferior uroup
1 formin<:; tht> nuiin mass of the mudeus consists of a central
nucleus situated in the niidille liiu' ( N iicl. centralis), of a nucleus
eontaininj^ snnill cells known as the Kdiuf^er-Westphal nueleua
\
* {
D44
TUR NKHVOUS SYSTEM.
(Xucl. Edinger-Wostphal.), and of four nuclei containing rather
large cells, two dorsal and two ventral, of which one is anterior and
the other posterior.
JVuclmed.ant.
J\/hd.Edinger Westphab
Lc'Vi'lx (>/ nirtiDttufram
}i'lii(li the jUitires (ic-
cuiii/innyiiKJ I'irliii'a
article irere taken.
Jifhel. latant
IDarksthemitSi
JfiuLdars.IlantJ
,A/iulvent.UanfJ
jyUcl.centmlis^
JVarldorxJffpo.iU.
(V. GudtJenj
JVatUvadJI (post.)
J\^cl.Trvc/il.
Fio. 004. — Scheme of tlic nuclei iiervoniin (iculoiiiotoriuiii. (After Perliii, Arcli.
f. Ophtli., Leip/,., 15(1. xxv, Alitli. iv, S. 297.)
The superior group, much smaller than the inferior, consists
of two nuclei — (1) a median nucleus (Xucl. med. ant.) and {'-l) a
lateral nucleus (\uo. hit. ant.). Perlia believed that root fibres
of the N. oculomoturius come from all of these groups of nerve
cells except the nucleus of Edinger-Westphal and the anterior
median nucleus. It will be noticed that Perlia's nucleus lateralis
anterior is in reality identical with the oberer Omilomotoriiisheni of
Darkschewitsch,* but, as we have seen, the newer investigations|&
* Darkschewitsch, L. Neurol. Centralbl., Leipz. (1885), S. 101 and Ibid.
(1886).
GROUPING AND CIIA1N1N(} TOGKTHEIl OF NHl'KONKS. 94:
t
have shown tliat I'erliu, Diirkschewitsch, and others were wronj,'
in believing that this nucleus gives origin to root fibres of the K.
oculoniotorius. It has, we believe now, nothing to do directly
with the X. oculoniotorius, but is connected with the fas-
ciculus longitudinalis niedialis on the one hand and with the
coinniissura posterior (distal commissure) on the other. Von
Kolliker has therefore referred to it as the nucleus of the pos-
terior commissure, and it has been described in a previous chapter
of this book as the nucleus fasciculi longitudinalis niedialis.
Von Kolliker has made a very careful study of serial sections
of this nucleus in the newborn babe, and his description should
be consulted by any one who wishes to study the nucleus thor-
oughly. He de(!ides that the X. oculoniotorius has on each side
essentially only oiu; nucleus.* From this main nucleus a round
dorsal mass branches off at the cerebral end. He does not find
any paired dorsal medial nucleus, but describes only an unpaired
central nucleus, which a}iparently correspoiuls to what has been
mentioned above as the nucleus inipar. Von KiHliker does not
find the nucleus of Kdinger-Westphal in his embryo preparations,
although he states that he sees it perfectly well in sections of the
adult brain.
The partial decussation of the root fibres of the Xn. oculo-mo-
torii was first proved for the rabbit by von (Judden. It has also
been made out in man by I'erlia and von K(">lliker and by van
Gehuchten in the duck (Fig. 0(i5). 'I'he decussation in human
beings has been perhaps most carefully described by Hernheimer.
This author believes that the distal part of the main nuclei give
off almost entirely decussating axones. In the most })osterior
ten sections he found exclusively crossed fibres; a little anteriorly
a few uncrossed fibres ajjpeared, which gradually became more
numerous; while at the middle of the nuclear mass the uncrossed
fibres predominated, and in the anterior half of the lateral main
nucleus there were no decussating fibres at all. He assumes that
on the whole one fourth of all the fibres from each nucleus
decussate. The decussation occurs as follows ; Out of all parts
of one nucleus there arise fibres which press more or less m\ the
medial side of the nucleus and descend at the same time toward
the median space, there to pass over like a commissure to the
opposite nuclear mass, in order again to ratiiate out, fan-shaped,
* ()/>. lit., S. 299.
J
[
uo
THE NEllVOlIS SYSTKM.
into the liittor. After passing throiigii the nucleus of the opposite
side, united in bundh'S they go tiirougli the fuscieuhis longitudi-
nulis medialis. Tlie fibres arising most dorsalward go out of the
opposite nuelear mass fartiiest ventralward, while those arisinir
more ventrally pass out farthest dorsalward. Hence one can
distinguish among the crossed libres some with longer roots,
others with shorter roots.
Fig. 605. — Niicli'iisorijiinisct lila ra<liciiliiria N. oculo-motoriiof an i-nihryo duck.
(After A. van (icliiiclitcn. Anatitniic <lii systenii' ncrvfiix dc rimninif, 2""
I'd., liimv.. 1M!I7. [I. till. Fit;. liW. ' us. a<iui'du(tiis c'i'rt'l)ri ; iji. cpfnd.viiiid
t'pitliclinni : J)), I'asciriiliis Imi^'itudinalis nicclinlis.
According to liernheimer, crossed fibres never leave the nuiiii
nucleus in the neighborliood of the median line. The crossed
fibres go through the fasciculus longitudinalis medialis in its
dorsal part, and, after a somewhat curved course, pass near the
lateral border of the red nucleus aiul then turn toward the
middle line to the region of exit of the nerve.
The uncrossed fibres from the nuiin nuclei arise unmixed
only from the proximal half of them. They leave the nuclear
fM
GKOUi'INd AND CIIAININ'C; T()(iKTIlKl{ OF NEl'IiONES. <)47
masses and puss exclusively between the fibres of tlu- fasciculus
longitudinalis luodialis which lie close to the middle liiu' — tiiut is,
to the most ventral lll)res of the fascic^dus longitudinalis tucdialis.
It seems likely that the various ijroups of nerve cells in the
nuclei nervorum oculomotoriorum are connected with one an-
other by means of large numbers of association neurones.
Ending in the nucleus nervi ocuh)moloiii of each side are
collaterals and axoiu's which in the nuiin come trom the tascicidus
longitudiiudis medialis. By just what paths, if any, other than
the fasciculus longitudinalis tnedialis the nucleus nervi oculomo-
torii is brought under the influence of cerebral sei'sory peripheral
nerves and of neurones, the cell bodies of which are situated in
the pallium, is not yet clear.
The relation of the nucleus nervi oculoiuotorii to flie nucleus
nervi ulxlucentis, on ae<'ount of the physiolojiy of tlu' muscles su|>-
plied by these two nuclei, is of the highest interest, especially with
regard to the hiteral movements of the eyes, the M. rectus medial is
being supplied by the nucleus nervi oculouiotoi'ii and the M. rectus
lateralis being supplied by the nucleus nervi abdueentis. Duval
and Laborde are of the o])inion that there is a crossed relation of
the oculomotor nerve to the contra-lateral nucleus of origin of the
nervus abducens nunliated by tlie fasciculus longitudinalis medi.ilis.
If their view be correct, libres leave the nu(!leus nei'vi abdueentis at
its cerebral extrenuty, enter the fasciculus longitudinalis medialis,
and farther cerebralward pass into the dorsal decussation of the
tegmentum, to go over to the other side, where they meet with tiie
root fibres of the nervus oeuh)motorius, and join them on their
medial surface. Spitzka, ■ the other band, and ( )bersteiner think
such a view unnecessary. .\ssumin<r that the M. rectus medialis is
innervated maiidy by crossed root tibres of the nervus oeulomo
torius. they suggest that a connection by means of the fasciculus
longitudinalis nu'dialis exists between the nucleus nervi abdueentis
aiul the nucleus nervi oculonu)torii of the same side. This would
afford an anatomical basis for the .syner<rism existing between the
M. rectus medialis of one side and the M. rectus lateralis of tlie other
side. Ileld's studies with Golgi's nu'thdil have demonstraUMl .so
many collaterals from the fasciculus longitudinalis medialis enter-
ing tiie eye-mu.scle nuclei that it seems very likely that the co-ordi-
nation of the activities of these various nuclei is brou<rbt about by
^Mlineans of fibres in the fasciculus longitudinalis medialis (Fig. tiOti).
A great many attempts have been made to localize in the nu-
cleus nervi oculomotorii and in the bundles of root tibres corning
I
948
THE NERVOUS SVSTEX.
VOmmJsaiira posterior
I' • ^v
Ir
Corpora geniculata
Nudciis lattrolis
snpciijr r/ir/isii/i
- I'elliculiis fiipvrior
ColHailiis
inferior
Fi'rmulio rcliciilaris
'iimcleus lotrralis nwtfius
fjffl\ 'W«: - -f:\iieleus ntrvi vestibiiti
■%m; I Uiterulis (DciUrs)
Forniiilic re/icii ' '•is
Iniicl^iis Uitenilii uilirior)
Risciciilii.i cercbrc.ipinalis
laUrnlis
i'cnlinuaiion in metliilla Mcni/dta
cf rirrmiins of fasciculi iircprii,
venlniles et latcralcs, cf lite
spinal cord.
Ftmciciilus cerebrvxpinuffs vcn/mtia
Fiii-dculi proprii, ventral csi>l hilcralcs
■Fafcu:iJiiii lercl'dllospiniitis Jersiilis
(direct cerebelloj- tract)
Flii
Funiculus dorfiili":
{•oiii-sc of the optic ami acoiislir reflex i)atlis in the
Alter II. Held. Areh. C. Aiiat. ii. Physiol.. Anat. Ahlh.,
Leip/,., 1S<»;5. S. ',"J!». Fi;;. 11. i Surl. III. nueleiis iiervi o<'iilo-iiiotorii ; Sii.f.l.iii..
mieleii.sfaseieiili loii>;itiidiniilis luedialis scu uucleus eommissunu posterioris;
All.)., uuelells ruber.
(iOtj.— Sehenie of the
forniatio reti<iilaris.
(JUOIMMXG AND ('IIAINIX(} TOdhmiKli OF NKUKONES. 949
from thoni structures correspoiuliii<^ to iiidividuiil eye muscles.
Thus, Ilonseu and V'olckers * in the dog stimuhited electrically
individual bundles of fibres coming out of the different portions
of the nucleus. 'Phey concluded that from before backward the
libres of the nervus oculomotorius in the doif iuive the following
arrangement: (1) Nerves of accommodation; {'i) those for tho
M. .sphincter iridis; (15) those for the M. re(!tus nu'dialis; (4)
those for the M. rectus superior; (5) those for the M. levator
palpebru' superioris; (()) tlio.se for the M. rectus inferior; (7)
those for the M. oblicpius inferior.
Other investigatf)rs (Starr, Kaliler and Pick, Ijeube, Si)itzka,
Siemerling, Westphal, von Monakow) have exaniinc^d the patho-
logical alterations in the nucleus in cases in which partial paraly-
sis of function had been observed during life.
Thus Starr t distinguishes in the nucleus nervi oculomotorii a
medial portion and a lateral portion. From the former he believes
there arise from before backward the libres for the ciliary muscle,
those for the M. rectus inferior, and those for the M. rectus medi-
alis; from the latter arise the nerve libres for the M. sj)hincter
iridis, Af. levator palpebra' sui)crioris, M. rectus superior, and M.
obliquus inferior. According to Kahler ami Pick, the pupillary
tibres of the nervus oculomotorius run in its most anterior root
bundles; while the posterior root bundles, they believe, are des-
tincti for the external muscles of the eye, and can be separated
into (1) a lateral group, governing the M. levator palpebne, the
M. rectus superior and the .M. obliquus superior, and (3) a medial
group, innervating the yi. rectus medialis and the ^[. rectus
inferior.
The case described by Leube,]; in which during life there had
been ptosis (paralysis of the M. levator palpebral on the right
side) and dilatation of the right pupil, and in which after death
a small apoplectic nodule was discovered in the dorso-lateral part
of the nucleus nervi oculomotorii of the right side, is worthy of
especial mention here.
* Ilensen, V., imd (\ V<)lckors. Uobcr den Ursprunjj; dor Acconinioda-
tionsiiervon, iiohst Renicrkiinpfcii iihcr (lii> Fiiiu'tioii dcr Wurzcln dos Nervus
Liciiloniotorius. Arcli. f. Oplitli.. \\vr\., l?d. xxiv (18TS). S. l-2li.
+ Starr, U. Allen. Op. cit.
X Tjeube. \V. Teller TTenlerkrniikiiiiLren iiu Gehiriisclicnkel in (ler(ie<renil
lies hinteren Vierliii,i,'el|iaiire.s. DeiUsilie.s Areh. f. kliii. Med., Leipz., Bd. xl
(lK8(')-'87). S. 217-237.
'•I
\
W^fi
\\
, 1
1
*,)'}()
TIIK NKinors SVSTKM.
Of espociiil interest, too, are tlie inve.stij;;iitions wliicli Imvc
been made by means of tlie method of Nissl, wliicli, as we have
seen above, lias thrown so niucli light ujxni the localization of
fnnction within the gray masses inside the spinal cord. Jlcic
the studies of Hernheimer and <;f Schwabe have been most ex-
tensive. Mernheimer* distinguishes between the extra-ocndai
and intra-ocular muscles, and finds that the extra-ocular muscles
arise from the medial ])orlion of tlie nucleus, while the intra-oculiir
muscles arise in the main from the lateral jiortion of the nucleus.
Schwabe,f under the direction of ilans Held, operated upon u
hirge number of rabbits with the juirpo.se of localizing the por-
tions of the N. oculomotorius concerned in the innervation of
the individual eye muscles. In his preliminary report he states
that his results prove that the view of Mendel, | according to
which the upper facial had its origin in the nucleus nervi oculo-
motorius, is jirobably incorrect, since on section of the nervus
facialis there resulted extensive typical degenerative alterations in
the nucleus nervi facialis, but not a single degenerated cell could
be found in the nucleus nervi oculomotorii.
When the whole of the orbital contents were removed he
found total degeneration of all the ganglion cells of the inotdr
type of the main nucleus of the nervus oculomotorius as well as
ol the lateral cells lying in the fasciculus longitudinalis medialis.
The relations are in part crossed, and Schwabe confirms von Gud-
den in that he finds that the cells in the crossed nucleus are sit-
uated in its most dorsal parts. Schwabe thinks that the oidy
muscle which receives a crossed innervation by means of the ner-
vus oculomotorius is the ^M. rectus superior. The root fibres
belonging to it come out of the dorsal half of the distal portion
of the ojiposite nucleus nervi oculomotorii, a region which cor-
responds approximately to the nucleus dorsalis described by von
(iudden in the rabbit.
The M. obliquus inferior is innervated by fibres arising from
* HenilieimtT, S. Tuiiervatimi dor Aujjoiiiiiiiskolii. DiMitseln' iiioil.
W'chnschr. (18!IT), No. :{'), S. 15;}.
f .Seliwabi', H. I't-berdie (iliedcruiig dt's Oeulomotoriiis-Ilauptkerns iiii
(lie Lugo (ler den eiii/.elneii Muskelu cntspreclicndeii (iebieto in demsellu'ii
Nourol. ('eiitrall)l.. I.eipz.. IM. xv (18()()), S. T!l2-Ti)4.
t Mendel, E. rdier den l\ermirs|)rungdes .Viigcn-Faeialis. Berl. kliii
Wehnsehr.. Hd. xxiv (1H87), S. !)13-916. Also, Neurol. Centralbl., Leip/..
Bd. vi (1H87), S. 537-542.
OROl'IMNd AND ('HAINTN(i TCKJETIIKU OF NErKONKS. 051
the ventrul half of tlie (listal portion of the nucleus ncrvi oculo-
motorii of the same side. The M. rectus inferior is innervated
by fibres iirisinj; fr(»ni cells situated in the proximal portion of the
nucleus nervi oculoniotorii of the same side and from some of the
lateral cells in the fasciculus longitudinal!."' 'edialis.
The cell bodies which send axones to tne M. rectus mcdialis
were not so easily determined. They do not apparently corre-
spond to a definite well-delined grouj), but the cells governing it
are spread out over the whole of that side of the nucleus lu'rvi
oculoniotorii which lies upon the fasciculus longitudinalis medi-
alis. 'J'hese cells include the greater part of the lateral cells, a
number of cells lying at the junction between the distal and jjro.x-
imal j)ortion of tiie nucleus and about half of the cells which, to-
gether with those which govern the M. rectus inferior, form the
most lateral ape.x of the proximal })ortion of the nuiin nucleus.
The fibres governing the M. levator palpebrse superioris and
the ^I. retrahens bulbi could not be connected with any cells,
although Schwabe thinks it is possible that the levator muscle
may be innervated by cells in the most lateral dorso-distal group
of the nucleus, possibly of the opposite side. Interesting from
the physiological staiulpoint is the fact that the >Im. re(^ti superi-
ores et obliqui inferiores, acting together in pure upward move-
ments of the eyeball, are innervated by the distal portions of the
nuclei of the two sides ; and also that the cells innervating the
.Mm. recti inferiores et mediales are intinuitely mingled in the
most lateral part of the proximal portion of the nucleus. This
latter region might very well be trailed, as Schwabe suggests, the
Concenjenzrentruin.
\
iiMK
/
SUBSECTION IV.
Neurones which enter into Conduction Relation with
the Lower Motor Neurones and throw the Latter
under the Influence of Other Centres (Interme-
diary and Upper Motor Neurones).
•u
\\ Ihav
'ji^
ClIAl'TKIt I>V1I.
INTKRMKDIAUY AND lI'l'KIl MOTOK N K I'IfOVES.
Kelutidii of periplicnil iH'iitript'tal neurones to motor nuclei — Golgi cells of
Type 11 iiitcrscguuMitiil — The triangular path of llelweg or the olivary
hundie of von IJcclitcrow.
It has already been stated {viile supra) that coUaterals, and
possibly tonninals, from great munbors of peripheral sensory neu-
rones enter into direct contact relation with the dendrites and cell
bodies of the motor neurones in the ventral horns (Fig. 007.) In
addition to this mechanism by means of which the peripheral
sensory neurones can come directly in contact with motor neu-
rones, the fibres of the dorsal funiculi can influence the motor
neurones by means of intercalated tautomeric and heteromeric
neurones with shorter and longer axones. In this way one sen-
sory fibre of a given neurotome can perhai)s throw motor neurones
in many segments of the cord under its influence (Fig. (!()8).
The lower motor neurones of the satne ventral horn and of the
ventral horns of the two sides can reciprocally affect one another
by means of Golgi cells of Type II. Th. . would be true of motor
neurones of the same segment or of segments immediately ad-
jacent.
(A) Those the Axones of which help to make up the Fasciculi ^j^
Proprii of the Spinal Cord. '■\'.
The motor neurones of the various segments of the cord iire
anatomically and functionally connected by means of lougitudi-
953
I , "
OUOl'I'INU AND ("I1AIMN(J T()(!KTlIi:il OF NKl' HONKS. J>r,3
iiiilly I'Xtciidiiif,' ussociiitioii neiiroiii's. Thus tlio cell bodies of
such association neurones situated in one se<jnu'nt of the (!ord
send out their axones into Mie fascicuhis ventralis proprius or the
fjiscicuUis hiteralis proprius, where tluiv nuiy ascend or descend, or,
bifurcatin<,s botii ascend and descend, usually close to the ventral
gray columns, to terniiiuite in the gray nuitter at a distance of one,
several, or very many segments distant from their site of origin.
The axones whicli connect the most distant segnu'nts with one
another are most peripherally situated in the white matter, while
miv
«»ri
l-'l(i. (i07. — Sclicnu^ of reflex nieelmiiisiii
oftlie siiiiial ciiril. I After A. vmi Ki>\-
liUer, IliiiKlliiieli <lei' (ie\v<'helelire,
lid. ii. 1H!M), S. Uil, Kif;. 3!ti).)
Fk;. fiOH. — Selieineof reflex iiieclianism
ill tile spiiiai I'urd. i After A. von Kill-
liker. Iliiiullmeli lier Oewelielelm',
lid. ii. l<eil>/.., ISlIti, S. DIM. Fif,'. K)0.)
I
those connecting neighboring segments run in the white fasciculi
close to the gray matter ( Flatjiii).* On tlie way these axones send
olT numerous collaterals to terminate in the gray matter of the
segments which tliey pass. That there are association neurones
of motor function has beeti proved by the cases of ])rogressive
niusculiir atrophy m wliich degenerated fibres have been found in
the ground bundles without tiny accompanyijig sensory disturb-
ance. These intermediate neurones between groups of nu)tor
* Flatiiii, F. Das (tesetz (ler exeeiilrisclieii rjasi'i'im^ <lt'i" laiigen Bahnen
iiii Kiic'keiiinark. Sitzber. d. Akad. <l. Wi.ss. zu bcriiii (IHUT).
!»:»4
THE NKIlVors SVSTKM.
.a
' •;■
1 i:'
m\ i
iiciirnnoH iiro ruorc niiriicroiis in tlic Intiilmr and ccrvinil cnlarpo-
tiiciits tliaii ill tin- portions ol' flu- •■(•nl of smaller calibre. 'I'liev
iiro very aliumlant in the nieiliilla oliloii^'iita aiul pons \aru|ii,
wliero they help to form the format io retieiilaris alba. One vd-y
important ^jroiip of axoiies of such loiij,'itii(liiial association ncn-
roiies is met with in the fasciculus lon^itmlinalis medialis (often
failed the posterior longitudinal linndle), by means of \vlii(;li
practically all thu motor nuclei of tho (cerebral nerves are func-
tionally cotiTU'cted with one another.
'I'his place seems as suitable as any to describe the " trian'Mi-
lar path '' of Ilelwcj,',* which extends between the nucleus olivaris
inferior and the spinal cord. Whether it is olivopetal or olivofiijrjil
ill direction ha.s not yet iieeii satisfactorily determined. In the
description {jiveii by H(dwe<j:, that author stated that the system
concerned consisted of an area of line libres trianj^iilar in shape in
cross-section in the upjx'rinost cervical cord. It was found bv liiin
in the central nervous system of individuals who during' life had
been insane. In the few bodies of non-insane individuals exam-
ined by him he could not tind the tnwt mentioned, and he
aci'ordiiifjly concludiil that the lineness of the libres in the " tri-
anj^ular path" repri-sented an abnormality occurring often in
the central nervous system <»f thi^ insane, 'i'hough Ilelwegs
studies were made with the carmine method, he was able to
establisli the relation of the libres of his "triangular path" to
the nucleus olivaris inferior. It was this author's idea that Iho
path had to do in some way with the conduction of vaso-
motor impulses.
.\ c(»mparisoii of Helweg's description with tlie plates and
text of a compreluuisive study of a case of degeneration f(»l-
lowing pontine ha'iiiorrhagc, published by Paul .Meyer f in 18SV',
makes it seem certain that ]Meyer saw the path much earlier than
did Ilolweg. .Meyer's Fig. I".* (/ aj)jiears to correspond exacllv
to llelweg's path.
In ISitt v. Ueohtercwj. <lescril)ed as tlie "olivary fasciculus"
* llehvcfj's I)n'ikiiiilt'iiliiiliii. (T. Ildwc;,'. .\rcli. f. I'sychiiit. ii. Xirvcii-
kr.. Ik'H.. M. xix (IHHT-'HH). II. 1. S. 108.
f McNur, !'. robcr I'incii Fail von I'iiiisliiim(irrliaf;it' tiiit scciiiKliiren
ncjiciu'rationcii tier Sciilcirf. .\rcli. f. Fsydiint. ii. Nervcnkr., Hcrl., IM. xiii
(1882), S. (;;!-!t8.
I V. Hcclitcn'W. \V. Fclicr (icii Olivcnstrang dos IlMlsiiiarkcs. XimiihI.
(Vntnilbl.. licipz.. Hd. xiii (18!»4). No. lr», S. 4;i;i.
4
m
OIHHMMNU ANIt CIIAINMNM} 'l'()(JI<:TnKll ol' NKl'llONKS. }|r,5
(<Hit'ni»tt'un(i) II 1)1111(1 of librcs wliicli in the distal roj^ioii of tlio
iiu'diillu (»l)loiifj;iitii lies close to the nucleus oliviiris inferior.
Aecordiii;,' to the Kussiiin neurologist, this bund of lihreH belonj^n
•'l(i. (illil. — Scctiiitis tliriiiif,'li tlic iiicdiillM (ililoiiKiita mill iipiMTccrviciil cord, sliow-
iiiK llic ii(iii-inc(lnlliil<(l iiliv(i-s|iiiiiil fiisciciiliis. The pynmiids arc not yet
iiicdiillatctl. ( After \V. vim Hecliterew, Die I,eitiiiif.'sl)aliiieii iiii (iehirn mid
Kiiekeiiniark. 11. Aiifl., Leipz.. ISH'I. i
{)i)('y
THE NKUVOlS S VST KM.
totlio yoimjjfost fihiv systems of tlic spiiml cord. Kvon tho fascic
uli ('or('l)ro-si)iiiiil('s (pyniiiiidtiU's) iirc iiu'dullatcd l)ofori> tlio til)rfs
of tlio O/irriisfnn/;/, so tliut it, is not until some time aflcr l)irth
that tile tihn'S become surrounded by myelin sheaths. Indeed,
one of tlie easiest methods of becomin<j; familiar with the position
of the j>atli is to stndy the medulla :ind cervical cord of the m w-
born i)al)e ( Imj;. CO'.i). In tli,' cervical cord tiu' "olivary buiidh""
lies at the junction of the lateral with the ventral funiculus at
the re_<:;ion of exit of the ventral roots. In the medulla it is
situated close to the lateral border of the [jyrumid. in cross-
section the area corres])()ndin,<,' to the.se tibres is lens-shaped in
the lower cervical cord, triaiiijjular in the mid-cervical rci^non.
At the level of tiu' nucleus olivaris inferior the bundle, accordiui,'
to von Heciiterew, suddenly disa])pears, but this invest isj^ator
•frants that there is no j)roof that its libres are directly rclateii to
the nerve cells of the olive.
The ilbres of the olivary buiuUe are amon^ the finest of the
white iiljres in the cord. While this bundle is medullaleil verv
lalt>, a iin)nth aft(>r birth, the majority of the libres of the fa.scic-
ulus lateralis proprius are medullatcd very early in tlie fo't us.
\'. Bechtercw favors the view that the axones of tin* tilu-es of the
0//w».s7;vr;//'/ arise from jierikaryons situatcil in the hoiuolalci'iil
vei\tral horn — that is to .say, the buiulle, in his opinion, is spiuo-
fui^al.*
The bundle has beei' fouiul de<;euerate(l in two cases by Kein-
holil,+ and in several cases recently by I*ick.| IJeinliold inclines
to the view that the bundle represents u centrifugal vasomotor
))alli. rick points out that the bundle is doubtless often overlooked,
owinsr to the fact that thouirh it can be followed as far down as
the junction of the pars cervicalis with the pars thoracalis of the
cord, it is usually very indistinct below the level of the second
cervical .segment, and the region in which it is distiiu'tly visible
is at ordiiuiry autopsies cut through very obliquely, so that the
tissue is unsuitable for study. If ('hiari's myelotome be employed
this dilliculty is easily obviated.
* V. Hcclitt'rcw, W. I)i(! lA'iluii;,'.sl)iiliiirii im (u'liini unci IJilrki'miKuk.
I! Anil.. I-cipz. (18!)!)), S. !»!)-l()().
f iViitsclH' /tsehr. f. NcrviMili., I-cip/., Hd. x, S. !)()().
I I'ick, .V. ncitrilf;*! zur I'litliolo^ric uml |Piitlii)l()j;iscliuii .\iiiiti)iiiio .Ics
<^'Ilt^,•lhl(■rvl•nsystt'llls init IJcinerkuiii,' /in- iiDriii.-ilcii .\ii!it()mi(' (Iossi'IImmi.
n.-rliii (IS!)H), S. •J-J'J-'.»:54.
«i|{(>riMN(i AND ('IIA1N1\(J T()(5ETIIi:il OF NKrUoNKS. <).-,7
I lirst iMK^ountoiTtl tliis {citli in tlic iiiodiillu (il)l()ii^!ita of an
infunt (Iciui of an oxtonsivc siiju'riicial burn. At lirst I luuj no
idea of its nature, but aftcrwani round tliat it corresponded in
shape and jiosition to tlie llelwe^'-liecliterew path. Its late niye-
iinization spi'ai\s, it seems to nie, in favor of its beini^ a eentrifu-
i^al ratlier thana centripetal tract. Moreover, the fact that when
it is degenerated the olive may appear unaltered is rather a>^ainst
tiu' view that this lihre .systi'ui takes its orii^in in the nucleus
olivaris inferior. Indeed, I do not feid sure that the term "oli-
vary buiuile" is well chosen. Could it not be that the lll)res of
ihe bundle conu' from hii^lu'r parts of the lu'rvous system, the
tibres bein}f so scattered above the level of the inferior olive that
ll.-s
f
Klii. (UO. — Dorsii-tiliiiil \ iiw (if llic niicli'iis olivMiis iiifi'iinr. i l''ri)iii n wiix
rccciiislriicliiiii liy Mi>s {•■luiciuc SmIiIm. IS!t!», )
Ihey are no Ioniser reco<fiuzai)le in Weigert preparation.^ as a dis-
tini'tly loealizable buiulle? As a matter of fact, Ilelweg's path
in the cervical cord corresponds very closely in position to that
of certain descendinjj; til)re systems in the venlro-lateral fascieidi.
I'ick even suirixests that Loewenthars "fasciculus nuirginalis
nuterior"* is identical with llelwe,i,f's piith. The more one
thinks of this tract in eoniu'ction witli other ceiitrifujjfal tibr(>
svstems in the ventnvlateral region of the (;ord the more he will
he imdiiH'd, I think, to h-^'^J^ate Ixd'ore he decides that it is a lil)re-
.. svstem which is entirely independent. Should it turn out that
'■«
* IjocwciUliiil. N. 1/ii n''f,'i(iii i)\i-iui\i(iiilc di' l.i (■.iiisulc inliTiic I'iic/ Ic
■ liicii ct la const it 111 iiiii ihi conlDri aiili'm-latcnil dc la iiiui'llc. lu'v. mh'iI.
ill' la Suisse roiii. (ISH(i).
» I
\
;
1
t)r)8
TIIK NERVOUS SYSTEM.
tho bundle known as Ilehvofi's Dreihtnteiihahny or von Bech-
torew's (Hirens/raii;/, is ivally only ono portion of a much lonjrcr
fibro systt'ni, tho cxpcrienco would not bo a novel oiu' ; on the
contrary, on ti rely siniilar steps have preceded the tinal unraveling
Flo. (ill. — Ventral view of tlif iiiiflciis olivaris iiil'fiinr. ( I'loiii ii wax rccini-
stnicliim hy Miss KUirciicc Saliiii, ISilil. I
in the history of tlie development of our knowledge of a number
of the more important tracts in tlie central nervous system. Tlic
curious sha})e of the olive is shown in Figs. (!10 and OH, niadc
from drawings of a reconstructior. fr'"'i serial sections by Miss
Florence Sabin. The gyri and sulci in the olive of the two siiics
agree.
t
(B) Those the Axones of which run in the Fasciculus Longitu-
dinalis Medialis and in the Formatio Reticularis Alba of the
Khombencephalon.
)
CIIAITKK LVIII.
INTKKMKDIAUY AND I I'l'KIt MOTOli N K I 1{( » \ KS (( OXTI N TKI)).
Tlio vestibulo-spiiial piitli — Distal (ixkiic syslt'ins from llio fjniy inassos of
till' formatio rt'ticularis j^risca.
In tlu> iiiodullii Jiiul jtoiKs are sitiialcM] groups of iR'uroiios with
axones running down to torniinato about tho motor neuroiu's of
the ventral liorn. Concerning the tracts which correspond to the
axones of these neurones our knowledge is as yet very indellnite.
One very important bundle, however, must be mentioned —
namely, the bundle of axones which descends toward the spinal
cord from the nucleus N. vestibularis lateralis (I)eiters' nucleus).
'Phis bundle is shari)ly ditlerentiated in sections of the brain of
the newl)orn babe, stained by Weigert's method, and F. Sabin
lias Iteen able to reconstrucit it.
This bundle degenerates after removal of one half the cere-
l)ellum, although, according to liisien Uussell and Ferrier and
Turner, only when the vestibular nuclei are injured at the same
time. Thomas* is inclined to think that the bundle lias its ori-
gin partly in the nucleus nervi vestibularis lateralis (Deiters)
and partly in the imcleus nervi vestibularis superior (von Rccli-
terew), a view whi(di a careful study of Weigert preparations in
tho newborn babe would tend to support.
This bundle of filires can be easily followed, especially when
degenerated, deep ('.own into the cord where th(> individual
iiicduUated axones turn in to terminate in the ventral horns. It
is not surprising, therefore, that von Monakow, after liemi.xcct ion
y of the s])inal cord in tho cervical region, found, after a long time.
*Thojnns, A. Tie i-ervelet ; Eliuli> iiiiatomiinii", I'liiiiqueet physiologiqiio,
Paris, 18!)7.
iM
./
{m)
TUK NERVOUS SYSTEM.
>
atropliy of tlio cells of Dcitcrs' luicknis. Tie was wrong, how-
ovcr, in conni'ctinji: the hnndlc with the dorsal fasciculi, for it,
undouljtcdly dosccnds in the vcntro-latci'al i,n-onnil l)undlc.
It would seem that this uncrossed descending vestibulo-spinal
neurone system has i)e("i described by various authors under
dilferent names. Many of the deseendiiii:: cerebello-spinal systi-ms
described by the authors in all probability corresjtoud to the
medullated axones of this system. I refer to the researches of
Basilewski, Hiedl, and others.
The fibres j)assing ventralward from Deiters' nucleus are well
shown in Kiir. iWi. 'i'hey come to lie close to 'lu ventro-iateral
])orti()n of the upward continuation of the lateral funiculi of the
spinal cord ; in all prol)ability they are more or less mixed with
the axones of the ascenditii^ neuroiu' systems wliicli i.«i;ikc up
Oowers' tract, aiul with the descending axoiu's fi'om the red
nucleus to the spinal cord. Tlu' libres from Deiters' nucleus,
however, to the cord teiul to occupy a somewiuit ditl'ertMit position
from the other fibres of the ventro-iateral funiculus; they come
to occupy the area between the tiuclei laterales and the rcniiiins
of the ventral horn. Having passed downward as far as the
sj)inal cord they lie in the peri])heral jiarts of tiie zoiu' of exit of
the ventral roots, occu})ying the lateral portion of the ventral
funiculus, aiul sitiuited, in the main, ventral from the ventral
horn. Some of the libres, it is stated, extend as far as the pars
lumbalis of the spiiuil cord, and are tdtinuitely exhausted bv
branclu's which turn in to eiul in the gray matter of the ventral
horn.
In addition to the descending fibres from Deiters' niu^leus
there appear to l)c many other desceiuling fibre systems in the
fornuitio reticularis. These have their origin in perikaiyons of
the fornuitio reticidaris grisea, particularly in the inferior middle
and superior central and lateral nuclei.
Those fibres descending from the nucleus centralis medius
and nucleus lateralis medius (von Hechtcrew's nucleus reticidaris
tegmenti ])ontis) have been best worked out. A good description
is to be found in Tschermak's recent article. Those axones from
the nucleus centralis medius can be followed to the fasciculus
longitudinalis iiH'dialis. 'I'hese thci-e divide into ascending and
descending branch(>s. The descending bi'anchcs apjiear to run
down into the ventral funiculus of the cord, there occupying the
so-called tissural part of the funiculus {Fissiiroisfraiiff of the
.ipi imi -y.i ,im
f»t I
ris
III)
Ills
lui
GROUPING AND CHAINING TOGKTllKR oF NKUllONKS. ()(;l
iff a>^=^>^|vf|?|
'- - _._*_»•'
5-r ^. S
- V /. — ^
III
^■'i'
i)G2
TIJK NEItVOUS SYSTKM.
ir;
i
.1 1
J'
Oerniiuis). (\)]liitoriil fibres aro <,Mvon ofT to the fonnutio rotkui-
luris on the Wiiy, iiiui to tlie ventnil horn as it is ])assed. Fibres
of this neurone system extend throuf,'hoiit the wiiole length of
the spinal cord. This niiglit be called the uncrossed descendin"-
spinal neurone system from the formatio reticidaris.
Another system of axones from the nucleus centralis mcdius
can be followed, ]>assiiig transversely through the fasciculus
longitudinalis medius to the dorso-lateral ])art of the o])posite
side of the fornuUio reticularis alba. Having reached that situa-
tion, the fibres bifurcate, the descending branches runniiii'-
spiiuilward in the bundle lateral from the fasciculus lon<>-itudi-
nalis medialis, and ventral from the genu internum radicis lu'rvi
facialis. The fibres lower down are more and more ventral) v
situated, and come to lie in the middle of the lateral zone of thw
formatio reticularis tlorso-lateral f rom the nucleus olivaris inferior
and medial from the ventral angle of tlu; mass of libres wliicli
represents the tracitus spinalis ncrvi trigeniini. The libres we
are considering now come to lie between the tractus spinalis
nervi trigemini and the nuclei funiculi lateralis; while in tlie
spiiud cord the buiuUe is situated in the dorso-lateral region of
the held occu])ied by the lateral ])yramidal tract, a little medial
from the descending fibres from the red nucleus and from the
direct cerebellar tract. The fibres of this crossed system from
the nucleus centralis medius can be followed down in the spinal
cord as far as the conns terminalis. It grows ever smaller in
volume owing to the passage of terminals and collaterals which
are distributed to the central zone of the substantia grisea.
Fusari * has described a case of degeneration ini2)licating the
fibres here mentioned.
lliv. speriin. (18%), vol. xxii, p. 117.
wm^mr
(C) Those the Cell Bodies of which are Situated in the
Cerebellum.
CIIAl'TER LIX.
INTERMEDIAUY A XO UI'I'KK MOTOR NEUROVES (f'oXTINrED).
The question of ccrolwUo-spinal paths — Studies of Marchi, Ffiricr iiiid
Turner, Ilisien llussi'll, Biedl, Thomas, and others.
In the cerebellum are situated also neurones the axones of
which descend in order to affect directly the lower motor neu-
rones. As to the exact position of these neurones and their
axones we are not well informed.
The studies of the descending oerebello-spinal tracts begin
with the investigations of Marchi,* who described such a bundle
ninning down iu the peripheral j)art of the ventro-latcral fascic-
uli of the cord. He believed that these fibres came mainly from
the vermis, that they passed from the brachium pontis and thence
by way of the fasciculus longitudinalis medialis and the stratum
interolivare lemnisci into the ventro- lateral fasciculi of the cord,
lie followed the degeneration through the whole length of the
cord, where it occupied two areas — (1) a ventro-lateral area ex-
tending from the stdcus ventralis to the ventral extremity of the
direct cerebellar tract of Klechsig, and (2) a more lateral area
situated just in front of the fasciculus cerebro-spinalis lateralis.
He believed that these fibres terminated in the ventral horn of
tlu' spinal cord, and that a lesion of the bundle containing them
led also to degeneration in the ventral roots of the spinal inrves.
The ventro-lateral bundle of Marchi corresponds to the descend-
ing cerebellar bundle, which has been described by Loewenthal,
Schaefer, Michael Foster, and others. The negative findings of
* Marclii, V. Sull' orijrinc e dccorso del pcduiiooli (•orehellari e sui ioro
mp[iorti copii altri ctMilri iiervosi. Mvo, FinMize(18!M). pp. I-;J8. .Msoin l{iv
spiT. di treniat., {{epfjio-Hinilia, vol. xvii (18)11). pp. ;{.'>T-;}()8. Also Transl.
ill .\ri'h. ilal. de biol., Turin, t. xvii (1H!»2), pp. 1!»0-201.
63 90:5
1'
.
I
904
TIIK NKRVOUS SYSTEM.
■1:
c
i
J^
:...(.!
Fcrricr and Turner,* liowever, huve made many nouroloffiats skep-
tical as to the existence of these centrifujijal spinal lihres arising,' in
the cerebelliiin, especially as the English investigators state jiosi-
tively that when one lobe of the cerebellutn is extirpated there
is no degeneration at all in the spinal cord. They found degen-
eration, it is true, in the corpus restiforjue, hut this, they be-
lieved, concerns the fibres extending to the inferior olivi's and to
the nuclei funiculi gracilis et cuneati, or wlien the vermis is
extirpated the llbres running to the nucleus of Deiters. They
assert that the degeneration described by Marchi is due to a
lesion of the nucleus of Deiters or to a lesion of the lemiusous.
Another English investigator, Risien Russell, f has carried out
a similar series of experiments, but, instead of employing the
method of Weigert, has used the more delicate method of Marchi.
On extiri)ation of the lateral lobe of the cerebellum, Russell finds
degeneration in the cor])US restiforme on the same side as the
lesion. These degenerative fibres are not scattered, but are lim-
ited to the lateral border of the restiform body. On examining
sections lower down, these fibres come to occu})y a more ventral
position inside the restiform body. They leave this bundle in
large part to become distributed to the nucleus olivaris inferior
of the same side and of the op{)osite side. A few fibres descend
into the ventro-lateral fasciculi of the cord in the cervical
region. These fibres, however, Russell states, are scattered aiui
few in number, and disappear at the upper part of the thoracic
When the vermis is removed (to quote Russell's findings fur-
ther) the corpus restiforme dogcMerates on both sides ; the fibres
become distributed in the formatio reticularis of the medulla,
going to the nucleus olivaris inferior of both sides. Some fibres
descend into the ventro-lateral fasciculi of the spinal cord. Rus-
sell does not lay much stress upon the desceiuling cerebellar
paths to the cord, but is inclined to agree with Ferrier and
* Fcrricr. A Hcconl of Kxpcriiiiciits Illustrative of the Syiuploinn-
tojoufv and Dcijciicrations Following; licsions tif the ('crcl)cliuin uiul its I'c-
dunclc and Keluted Structures iti Monkeys. I'liil. Trans. Roy. Soc. liOiul..
vol. clxxxv (I?.) (lH!ir)).p).. 71!t-TTH.
t Russell. J. S. R. Deircneration Consequent on Kxperiuiental Lesions of
the ("ereiielliun. Rroc. Rov. .Soc. Lond.. vol. hi (18!)4). y>p. ;i(«-;5().'5 ; iiiiil
Experimental Researches into the Functions of the Cerebellum. Phil. Trans.
Roy. Soc, vol. clxxxv (B) (18!»5). pp. Sl!>-8tn.
UUOL'IMNO AND CHAINING TOOKTIIKIi OF NKUUONKS. (J(;5
Turner that the markcMl degeiu'ratioii observed by Miirchi de-
pends upon an aecidentiil lesion of the nucleus of Deiters.
A stout suj)porter of the view that extensive bundles of fibres
descend directly from the cerebellum into the spinal cord is
found in Hiedl.* After reviewing,' more or less thoroufjlily the
bibliography of the subject this investigator describes his own
Muatomical findings after section of the corj)U8 restiforme. lie
decides in favor of the centrifugal cerebellar j)ath of Marchi,
Fk;. (U:?. — DosfcndiiiK (Icfrciicratioii in llic spinal cord after oxpcriiiuntal scctidn
of the corpus rcstiforiiic. i After. V. Miedi, Neurol. Ceutralli!., 15(1. .\iv. ISII"),
S. Ill, \'\n. 1.) Level of upper cervical cord, liiedl is prolmlily wrou^; in
thinking that these lihres come from tlie cereheMum.
and states that he can follow it from the uttermost portion of
the cervical cord almost as far as the sacral enti of the spinal
oord. One bundle runs in the ventro-lateral fasciculus in the
area corresponding to that described by Afarchi, Loewenthal,
Foster, Schiifer, and others, 'i'he other bundle descends in the
funiculus lateralis, and, he tisserts, in the exact area occupied by
the lateral pyramidal tra(!t — a very imjKirtant finding if it be
oonfirined (Fig. (Il.'5). He disagrees with Marchi, however, as to
the way in wliich the fibres get from the cerebellum to the cord.
Whereas Marchi believes that they pass from the cerebellum
l)y way of the brachiiim pontis through the fasciculus longi-
tiidinalis medialis, and the stratum interolivare lemni.sci to the
* Biodl, A. Ahstci^joiule Kknnhirnbalineii. Neurol. Ceiitralbl., Leipz.,
lid. .\iv (1895), S. 4:34, 493.
%
4
m
!)('.(]
TIIK NKIlVors SYSTKM.
TTt
cord, IVwdl believes tlmt they go from the cerebellniii to the
corpus restifoniic, and thence, partly throu};h the fasciculus
lonf^jitudinalis but mainly through the ventro-laterul ground
bundles, to tlic spinal cord.
Thomas, in Paris, has also employed Marchi's method, and
states that total removal of the cortex of one cerebellar hemi-
sphere causes no dej^eneralion in the spinal cord. On extirpation
of one whole hemisphere, however, he finds distinct descendini^
de<^eneration in the spinal cord of the same side in the ventro-
lateral fasciculi, whi(!h can be followed as far as the lumbar
region. lie is of the opinion that these fibres arise in the nucleus
dentatus, and that they pass through Jk'chtercw's nucleus and
ills, )
il.nr
Itir-
llth
(MtOl'IMXl} AN'I) CHAININCJ TOdlOTIIKli OK NKlJItONKS. \u\^^
would tlicii occupy flic Hiimo rcjjiou in tlic funiiatio rcticuliiris as
(Iocs till! l)uiull(! wliicli wo know descends Trom Deilers' niieU'iis to
tlio spinal cord; Thomas states that if, alon}]^ with the lesion of
the cerobellum, the nucleus of Deiters and the nucleus of von
Mechterow be injured, tlio dcscendin<j deiieneration in this de-
scendiiifj tract is much more extensive, 'i'iie (indi!i<;s of Uasi-
Icwski after section of the corpus restiforme are illustrated in
Figs. (514 and (JIT).
On the whole, it must bo confes.sed that our knowledjje of
the descendin<? cerebello-spinal paths is at present unsatisfac-
torv, the results of the various investi<;ators beinj; markcdlv (!Oji-
tradictorv. . As far as one (^an iudiie from tlu^ mass of conilict-
iiifj (lata before us, it seems likely that a certain number of
fibres descetid from the internal nuclei of the oerebollum to the
('(inl, and jiossil-Iy a few axones from I'lirkinje cells in the cere-
bellar cortex, especially since Hainon y ("ajal * linds a few axones
of I'urkinje cells passim; directly into the i-orpus restiforme.
It seems likely, however, that the inllucniio of the cerebellum
upon the spinal cord is mediated maiidy by means of neurones
* K'.'iiin'in y ('fij)il. S. Hcitrai^ ziiiii Stmliiiin dcr -Mfiitill;i Olilonjjatft dcs
Kli'inliiriis iiml dos Ursprung ilcr (ifliiriiUfrvcii. Dciitscli von Rreslor,
I,ci|./.. (ISiHi). S. 131.
i.
'M\H
TIIK NKIIVOUS SYSTKM.
' I
iiitorcalutcd between the cerebolliun mid tlio cord. These inter-
calated neurones consist, in the first ])laco, of those having their
cell bodies situated in tlie nucleus nervi vestibuli lateralis of
Deiters, and j)os8il)ly in the nucleus nervi vestibuli supi'iior
of von Hechterew, and ('^) those having their cell bodies situ-
ated in the nucleus olivaris inferior of the two sides. Von Kiii-
liker has especially emphasized the importance of the nucleus
olivaris inferior as a way-station between tho cerebellum and
the sj)inal cord. We know iu)W that, although the majority
perhaps, of tho fibne cerebello-olivares consist of axones arising
from cells in the nucleus olivaris inferior and i)assing to the
cerebellum of the oj)posito side, a certain mimbor of them
consist of medidlated axones arising from cell bodies situated
in the cerebellum of one side, and passing across the raphe to
terminate in the nucleus olivaris inferior of the opposite side
(von KTilliker, Huss(>Il, Hicdl, Thonuis). The connection be-
tween the nucleus olivaris inferior and the spinal cord must be
made by means of the fasciculus ventralis proprius and tho
fasciculus lateralis proprius. The so-called olivo-sj)inal bundle
has been described above. In Weigert-1'al ])reparations of the
medulla of the newborn babe large numbers of medullated fibres
can be seen exteiuHng between thesis fasciculi proprii of the
cord and the hilus nuclei olivaris inferioris. How many of
these fibres pass from the cord to terminate in the olive, and
how many pass from the olive to terminate in the cord, it is as
yet impossible to say. The study of experimental degenerations
and of suitable (Jolgi preparations must be relied upon to give
us the information which we desire upon this point.
«Di Those the Cell Bodies of which are Situated in the Mesen-
cephalon and Diencephalon.
CllAI'TKi; I.X.
INTKRMKDIAUY AVn II'I'KU MOTOU NKUKOVKS (rOVTrNrKn).
'I'lip path from tlic superior collicMilii.s Id tlio s|iitml cord — 'I'lic path from
tlio red llll(•h■u^ to the spinal cord — 'I'hi- fascieiihis legmenti ci'iitralis or
viiifnile Ildiil/enbiihii.
That the lower motor nciironps stiiiid to a cortain oxtoiit
iimler the iiitiiienci' of iiciifonos whose cell bodies are sittiated in
the mesencephalon there can be but little doubt. lieferenee has
already been made to the fact that many optic neurones and au-
ditory neurones of th(* second order terminate about cell bodies
ill the superior colliiuilus of the corpora (piadrigemina. 'I'he
axoncs of these cells pass down, decussate, and sooner or later
join the fasciculus longitudintdis medialis, the fibres of which, as
we know, come into contact relation with the motor nuclei of
the cerebral nerves, and with the ventral horns of the cervical
cord. Fibres frcnn the nucleus lateralis superior to the fasciculus
loiigiludinidis medialis are well shown in Fig. (!l(;. In this way
the connection of the corpora quiidrigemina (and of the retina)
with the neurones in the cerviciil cord, the axones of which pass
through the rami communicantes to the symjiathetic and lead to
alterations in pupillary contraction, may be explained.
The studies of Held and Tsclierniak make it appear that this
crossing spinal system from the middle iind deep gray matter of
the superior colliculus of the corpora quadrigemina forms in
large ])art the decussatio tegmenti dorsalis { fontnineartif/c Haiih-
e>ikreuzu7i(/ of ^foynert). Tfaving crossed the raphe, the fibres
lie in a separate bundle which goes through the whole brain
stem just ventral to the fasciculus longitudintdis medialis.*
According to Held, collaterals are given off oti the way to the
* Praedorsales Ldngshundel of the Uermiins.
969
b
1
A
I'l
970
TIIH XHHVors SVSTH.M.
i
deep gray niattor of tlio siij)orior colliculus uiul to tlio stratimi
grisi'uiu contrale of the same side, and, by way of the dorsal
coiniiiissuro, to tlie opposite side. Collaterals are also sent into
the nucleus nervi oeulomotorii of each side, ami to the nucleus
uervi troehlearis aiul nuclei nervi abdueontis of the opposite side.
Ts(diermak has fouiul that the distal axones here concerned give
oil' also collaterals lateralward to the cells of the fornuitio reticti-
Niirlr}iK III tenth's
s.'/ii liiir
' li'ilmiiii.
'•<llltlll urial'UIII
iiiliiili
/■'</«■/(•»/»« liiiuii
tiiilhiiilis nil'-
<li<ilis.
\ Juhiin frniii II i(-
clriis nihi r hi
sfriititiii itrisf-
iiiii ciiitnilf.
Xllflt'lin filsriciili
lllllllilllllillillis
liniliiili.i
Hmcliiiiiii mil June
tiritm.
Nuclfiis nilitr.
Fi(J. (il(). — Scctidii IliniUKli till' iiiiillniiiii illustnitiiif; the rt'lation iif the iiuclius
lateralis siipiriin' Ui (lie fasciculus l<uinitU(liiialis uumMuMs. i After II. Held,
Abhaiidl. (I. siclis. (iesellscli. tl. Wissensch., Leip/., lsi(2, Tali. iii. I-'i^. 11.)
laris, especially to the nucleus centralis medius and the nucleus
centralis inferior. Some collaterals cross the rtiphe to the same
nucleus of the other side. FiOwer down the bundle (U)ncerni'd
comes to occupy the ventral part of the iissiiral portion of the
ventral funiculus, and exhausts itself by giving off collaterals and
terminals to the colnmna grisea ventralis of the same side, but
])artly by sending axon s ttirough the commissura ventralis alba
to terminate ii. tiie contralateral colunina grisea ventralis. The
longest stem fibres of the neurone system here under considera-
tion reach us far down as the lower part of the })ars luml)alis.
It seems likely that fjoewenthars mtirgimd fasciculus is identical
with the system here described.
A very interesting series of experiments is that made by Boyce.*
* Hoyw, U. Neun.l. (Viitriil.l.. Leipz. (lMi)4), S. 4fi().
■£.%■
GllOUl'lNG AND CHAINING TOGIOTIIKR OF NKUUONKS. J>71
W^\]
He iiiiule litMiiisec'tion of the midbrain at tlio level of tlio third
nerve in t-ats, and found, by Marelii's niethoil,desi'endin<; de<;en-
oration tliroujfji the dorsal tegmental decussation of Meynert
into the bundle which runs just ventral to the fasciculus longi-
tudinalis niedialis of the opposite side. He followed these libres
down into the tissural part of the ventral funiculus of the cord
as far as the pars tlionicalis.
Boyce also found degeneration through the ventral tegmen-
tal decussation of Forel ; further down, degenerated libres at
first dorso-lateral from the lemniscus niedialis, passing through
the region traversed by the stem of the facial nerve; then ventral
from the tractus spinalis nervi trigemini, and dorsal from the
Fasn cuius longitudiiiaHs
medialis
Colliculus
inferior
Brachium
conjundivum
ri<j. til".— Section tliriiiijili llic |i(iiis sliDwiii}; (IcKfiicnitioii (if tit)ns iit'tcr rriiiuval
of (lie left lu'iiiispliiic. (Al'irr U. lioycc, Nciiidl. ( 'ciitnillil .iii/., \V\. \iii,
18!lt, S. Ki7, V\\i. I.) II. (IcsictidiiiK dcKoiirnitioii of the I'm i ccrt'liro-spi-
llillcs ; />,(lfsr('ii<lii|i; (Icfji'iK ration of the rasciciilus loiiKitiu ncdialis; c,
(U'sccnilinf; di'Ki'iu ration of ihc lilircs of the iar-ci<iiius vciu lateralis ( from
tile di'ciissat ill tesnienti dorstlis Meynerti': J. deseemliiif; def;eneralion of
tlie lilires of the fasciculus latenilis i from the decnssitio ten "«'nli ventralis
Kondi I ; c, de^rener.ltioli of the radix desceudcns ( meselicelihalica ) N.
trigemini.
i
\
nucleus funiculus lateralis into the spinal cord, where the fibres
lay just in front of the degenerated lateral pyramidal tract.
The degenerated fibres could be followed as far tis the lumbar
1 I
I
<.>72
THK XEIiVOUS SYSTEM.
i.:-t
i"
L
cord. Tlie findings in Boyco's cases are well illustrated in Ficrs,
G17, G18, and GU).
It seems likely, as Tsclierniak suggests, that lioyce's bundle
from the dorsal tegmental decussation corresponds to Ileld's
Fl<i. HIH,— Section sliowiiif; (U'Ki'iicnitioii of tlic' (Icciissiitic. iivniiniduiii alter
rciiiiiviil of the left lieiiiisi)licrc. (After K. Moyee, Neurol. ( Vntnillil.. ]a-\u/.
15(1. .\iii. ISill. S. ItiS, I'Mji. -'. I '/, ileneiiei-.ition ol pyraiiiis. left si(l<''; ,i . cli'
{,'eiieriitioii of tilires in llie region of the fascieulns eerelno-spiniilis ventriili>-
h. lilires from the fascieulns lonj;itn<linalis nudialis ; c, tihres to the fasciiMihi.-i
ventro-lateralis i from the ilecns.s;Uio te>;uieiiti dorsalis Meynerti).
crossing spinal system from the superior colliculus to the ventral
horns. Boyce's fibres from the ventral tegnsental decussation
l)robabIy correspond to (1) the crossing desceiuiing system from
the. red nucleus ; (3) the crossing descending system from the
nucleus centralis superior and the nucleus lateralis superior.
The crossing descending spinal system from the nucleus
ruber of the tegmentum connects the nucleus ruber with tlio
spinal cord. The axones arise from perikaryons in the nucleus
ruber. They then pass through the decussatio tegmenti ventralis
Foreli, and come then to be situated ventro-lateral from the
nucleus ruber of the other side (Held, Kamon y Cajal). At tiic
level of the colliculus inferior the axones of this system lie
among the fibres of the medial part of the lemniscus lateralis.
Further spinalward these fibres occupy a region situated between
the tractus spinalis nervi trigemini and the nucleus olivaris
superior. In its descent through the niedidla this desceudiiii;
system from the red nucleus is mixed uj) with the fibres which
ascend in frowers' tract. The fibres pass into the region of the
medullii, which corresponds to the upward continuation of the
ventro-lateral funiculi of the cord. The fibres of the descending
JJB««,^_.~ ^
UKOUPING AND CHAINING TOGKTUKU OF NEUIIONES.
5)73
system from the red nucleus ure situated somewhat laterally in
the bundle, but niodio-ventrally as regards the tractus spinalis
iiervi trigeinini, and lower down, lateral from the nucleus funiculi
lateralis. In the funiculus lateralis of the spinal cord these fibres
assume in the cross section the form of a comnui lying medial
from the direct cerebellar tract in the lateral part of the area
corresponding to the fasciculus cerebro-spinalis lateralis. 'J'he
comma extends from the dorsal horn ventralward as far as the
region of (Jowers' tract. The bundle is gradually exhausted,
owing to the giving otT of collaterals and terminals to the sub-
stantia grisea, especially to the lateral horn and the central
zone of gray matter. The longest libres reach as far down as
the pars lumbalis medulhe S2)inalis. This bundle })robably cor-
responds to that described by Ferrier and T'urner as descending
from the nucleus lemnisci lateralis. It appears to have been
degenerated also in Biedl's cases. Tschcrmak is of the opinion
ens
tho
ous
iilis
th,
tlic
lir
alls,
k'eon
'aris
iiiiij
Fki. ()19. — Sections tlirou^li tlic ui)|)('r jmrt of tlic ccrviciil spiiiiil cord. (After
R. Hiiyce. Neurol. v'eiitniU)!.. Lei|)z.. lid. xiii. IHiU. S. 4t)9, Fit;. 3. ) 1. De-
feneration ill'ler removal of the left lieniispliere, r\ji\\t side ; <(, defeneration
of lihre.s in the rejiiou of tlii' fasciculus cerehro-spinalis lateralis ; c, defenera-
tion of lihres of the fasciculus ventro-lateralis (from the decussatio tcKnienti
dorsjilis Meynerti) ; d, deKenenition of tibres of the fasciculus lateralis i from
the decussatio te«nienti ventralis Forcli). II. DeKcneration after removal
of the motor zone of the left hemisphere, riKht side; a. deKcneration of the
filires of the fasciculus eerehro-spinalis lateralis. III. Deneneration after
removal of the left liemisphere. left side ; no detieiieration of the fasciculus
eerehro-spinalis latenilis ; h. dc^'eneration of tihres from the fasciculus toufji-
tudinalis medialis ; (/, de;;enenition of tihresof the fasciculus lateralis, section
lielow the level ol their decussation.
that in Basilewski's case, and in the experiment of Sakowitsch
reported by Bechterew, this bundle from the red nucleus was
also degenerated.
The view that from the diencephalon axones pass downward
%
974
THE NERVOUS SYSTEM.
which can influence the motor nuclei has met with general ac-
ceptance, though in just what portions of the cor])us striatum
and thalamus the coll hodies of these neurones arc situated
and in what tracts their meduilated axones pass downward,
whether in the tegmental tract or in the bundles '^f the basis
pednnculi, we are as yet almost completely ignorant. Von Mou-
akow assumes that all thalamic; tracts are corticopetal, and that
the thalamus does not represent a motor centre intercalated
between the cortex and the lower motor centres.
Von Bechterew and Flechsig have described as descendiuir
from the diencephalon a special bundle which they call the cm-
tnile llanhenbahn. I have referred to it in various illustrations
of the region through whitdi it passes as the fasciculus tegmenti
centralis. There seems to be some doubt as to whether it lias its
origin in perikaryons in the thalamus or in the nucleus lenti
formis. The bundle is easily isolated by the method of myelini
zation, as the libres are meduilated very late. It has also l)ueii
described degenerated in a recent case studied by von Bechterew.
Thus far studies by (iolgi's method of this fasciculus are wantiug.
It appears to terminate in the nucleus olivaris inferior. Its posi-
tion in the central region of the ])ars dorsalis pontis gives it its
name. [For figures illustrating the fasciculus tegmenti centralis
the index should be consulted.]
.J)
^S ' 'ift (
1
(E) Those the Cell Bodies of which are Situated in the Telen-
cephalon (Pallium and Rhombencephalon),
We have much more exact information conceriung the non-
rones which throw peripheral motor neurones under the inthi-
tMice of tlie pallium. These nuiy be divided into (a) neurones
with medullated axones, making up tlie fibres of the pyramidal
tract; (It) neurones with moduHated axones corresponding to the
frontal cerebro-corticopontal ])ath ; {c) neurones with medullated
axones corresponding to the temporal cerebro-corticopontal path ;
{(I) neunmcs which possibly connect the occipital region of the
cortex with tlie lower motor neurones; and (e) neurones con-
necting the olfactory region of the cortex with the lower motor
neurones.
CllAPTKR L.\l.
TlIK I'VItAMIDAl; TllACT.
Ill' iiiiilnr (iron "f tlic cortex — I'criknryniis and dfixlrili's — Course followoil
liy the a.\<iin's — Dcciissut io jiyraiiiidiiin — l-'asciciilus (•(■rt'l)ro-s[iiiialis lali'-
ralis — Fasciculus ccrcliro-spiualis vciilralis — Studies l)y t lie einbryoloj;-
ical uietlioil of I^'lochsiij — I'hysiolo;.'ical e.\|>eriineut ineludinjr olectrical
sliinulatioii — Secondary degenerations of the jiyramidal trad — Studies
bv (iolici's mot hod.
I.
1. Those the Axones of which Correspond to the Fasciculi Cerebro-spinales or
Pyramidal Tract.
(Ad >i.) TnK neurones witii axones corresponding to the fibres
of the pyramidal tract liavc been most carefullv investigated, and
arc the best understood of all the neurones now under considera-
tion. Tlieir cell bodies tire situated in the so-called motor area
of the cortex (znnr innfrirr of Charcot). Their axones extend
from this situation to the motor nuclei of the cerebral nerves iind
to tiio cell bodies of the periph(>riil motor iieuroiu's situated in
tlin spitud cord, .some of tiiem reacbiiiir as far as the lowermost
portion of the sacral spitial cord. Thus some of the motor
975
i
i
1
■ f
i
97(i
THE NKUVOUS SYSTEM.
axones are among tlie longest of cell processes occurring in tin.
body.*
The motor area of the cortex, corresjionding to the sitnation
of the cell bodies and dendrites of the neurones we are now de-
scribing, includes the anterior and posterior central gyri, the feet
of the superior, middle, and inferior frontal gyri on the external
surface of the hemisphere, ami the lobulus paracentralis on the in-
ner surface of the hemisphere. It will be immediately noticed tluit
this area corresponds closely to the region of the cortex in wliidi
terminate the axones of the central sensory neurones wliich carrv
impressions from the periphery of the body, muscles, and into mil
organs to the cerebral cortex. Indeed, the motor area corre-
sponds more or less closely to what has above been designated as
the " somajsthetic area " of the cortex {J\ orperfiUihJi are of Munk
Tastsphare of Flechsig).f In this area are situated numy niillious
of cortical pyramidal cells, each supplied with one main stron^
apical dendrite running out to branch more or less freely in the
molecular layer of the cortex, with dendrites of snudler size com-
ing off from the angles at the base of the pyramid, and with
an axone which soon becomes medullated and runs into the white
matter to form one of the constituent ilbres of the centrum sfinj-
ovale of the hemisphere. By no means all of the pyramidal cells
situated in tlie motor area belong to the group of neurones which
we are just now considering. Besides large numbers of Golgi
cells of Type II of local significance, and cells with axoTies ascoiid-
ing to pass out toward the surface of the cortex (cells of Martiii-
otti),J a great number of these cells represent the neurones of
association systems connecting neighboring gyri, gyri at a dis-
tance from one another in the same hemisphere, and gyri in one
* Strictly spcakinp. tho pyrnniidal tract does not include tlic axones .^'ninjr
to tho nuclei of the cerehral nerves, l)ut only tiiose fjoinj; throufjii tlir |iyrii-
mids of the medulla to the spinal cord. The tendency is becomiuf; gcncnil,
however, to extend the term.
t Tamtiurini has s^tated as a general law that motion and sonsaticii are
represented together in the pallium, and (iolgi has strongly supported a sim-
ilar view.
X Martinotti, C Di alcuni nuovi gruppi di cellule cerebrale siinili ai
cosidetti granuli del cervelletto. Ann. di freniat. e sc. atT., etc.. Toiiim
(1H8H-'H!)). i, i)p. 221-2-2().—(\)ntrilnito alio studio della cortcccia cerebrale. eil
aH'origine centrale dei nervi. .Ann. di freniat.. etc.. Torino, vol. i (IMSS-'.SO),
pf). 314-:i:!3. Traiisl. in Internat. Momitschr. f. Anat. u. Phy.>iol.. l.ii|iz.,
Bd. vii (IMIIO). S. (W-JM).
OROUPING AND (JllAINlNG TOUKTllKR (»F NHl'liONKS. <)77
>
v..
•>:r~.
X
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A
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M
1.* ■ .
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M
V
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i
I
Ki(i. iWO. -Liirjic i),vruiiii(iul ctlls uC ilic ('(irtcx. (Al'tcrW. Vdii licclili rcw. Die
Lt'ituiiKsliiiliiu'ii iiii (ii'liirii iiiul Kuekonniiivk, Li'ii>z., II. Aull., 1809, S. 450,
4i")7. l''ij;s. 417, 41S.J
OTS
TIIK NKUVOrS SYSTKM.
hotiiisjOicro with those of thi- otlu r. Iiulccd, only ii ri'lativciv
small miinbiT of pyniiiiidiil colls in tliu motor urea ot tlie eortcx
represent cell bodies of neurones, the axones of whieh pass uown-
ward through the cerebrospinal axis to come into conduction w-
lation with the lower motor neurones. The cell bodies of these
pyramidal cells are, as a rule, of rather lar<,'er size than tlicir
neijjhbors, and iiudude the large pyramidal cells (Kig. (;•.'()) de-
scribed by Bevan Lewis and by llammarberg and tlio so-ealhMJ
giant pyramidal cells met with in these regions (Fig. *W1), espe-
cially those gigantic! cells in the lobulus paracentrulis (/i'iV.,77/.
pyraviiilcmrllcn of Hetz) the axones of whicii have to run the
longest distance (to the lumbar and sacral cord) (Fig. ^Vi'i). 'I'lio
structure of the cortex of the gyrus centralis anterior is repre-
sented in Fisr. Ov'."}.
:\
Fl(i. tWl. — DiiiKi'iiiii sliciwiiiK iMisilioii mikI imiiilier of };i:iiit iiyraiiiiilal cells in Ilic
;;.vriis fentnilis aiiteriiir of w niiiii I'orly-tlm'e years old. (Alter A. veil Kol-
liker, llandlMieli d'l (iewclielehre. Fxl. ii. S. ti.io, I'ii,'. 730.)
The exact relations of the cells in this area to one another ami to
incoming fibres have been carefully worked out by lievan L(>\vis,*
* Lewis, B. On the Comparative Structure of the Cortex Cerebri. Mriiiii,
vol. i (1878-'79). pp. 78-90.— Lewis, H., and II. CJiirke. TheCortieai li.iin-
ination of i\w Motor Area of tlie Hraiii. Proe. Roy. Soe., Loud., vol. xxvii
(1878), pp. ;}8-4i). — Lewis, W. 15. Hesearohes on thi! Coiuparative Stnieturo
■»i;
(JII()U1MN(} AND CHAINING Tod KT 1 1 Kit oK NKlM{oNKS.
lt?.»
(i(»l<,M,* l>!iiii(')ii y ('iijiil.t llaiiiniiirhcrji, K. A. Schiircr, Andricz-
/,('ii, Von Krdlikcr, uiid otiicrs. 'I'ho cell botlius willi 11x01108
Xi'if'' . 'i-*J^t*'-- ■■'■■
.=^^,
T ■
I
n'v
Flii. (U^. — Xoniial IJrlz cell froin tlif liiiiiiaii paracciitral luliiilr. AfliT Ailoli"
Mi'jH'i", AnuT. .loiirii. of Iiisiuiity, vol. liv, lH!t7. 1
of till' Cortex Ccrchri. I'liil. 'I'niiis. itoy. Sue., liOiid.. vol. olxxi (ISHO), pt. i,
pp. :!r)-r)4.
* (ii)l<,n, ('. Sulla liiia iiiiiiloinia (lt'j;li orf^iiiii coiilrali ilcl sisloma nervoso.
Milano. IHHf) (If^^-)). Ilucpli. Hvo. p. -l\\.
t i{amc')ii y ('jijal. S. Soliro la oxisliMuia de ('('liilas nervidsas psiiocialo.-i
I'll la in'imiira capa de las oircimvdliu'ioiu's eorcliniies. (iac. iiu'mI. catal.
liMi'col., vol. xiii (IHDO). pp. 7;iT-73i). — Sol)iv la oxistcucia di- bit'iircacioiies y
iii|;iii'i'al(>s iMi los inTvios scnsitivos crancalos y siistaucia t)laiii'a del coro^ni.
(iiic. sail, dc IJaro'l., vo|.iii"(l.S!K)-'!n). pji. •,'SL'-'JH4. and in ('roll, inrd., Valcii-
lia. vol. xiv (1H!)1). pp. "JIJO-JIJ'J. — Kl iiiicvo ooncopto dc la liistolos^'ia dc los
(■('iilros norv iosos. Itcv. dc cicii. iiicd. dc liarccl., vol. xviii ( ISO'J), pp. ;i(i!-
:!7(): 4:)T-47(;.
(!4
'V
1^'
!t80
iV
TT"
^
^•Jl__
^"
Till-: .\KI{V(»rs SVSTK.M.
ii(*'\ng to till' iiKttdr nuclei of the fiicc arc situ-
ati'd on the latiTul surface of tlie cortex jii,-t
above tlie Sylvian lissure. 'I'liose ginu<i to the
cervical enlar<fenie!it of the spinal conl ("■ov-
erninj; the lower motor nourones of the neiiru-
lonies which innervate the muselus of the iip.
))er linil)) arc situated in the middle region,
while those the axones of which run to the
lumbar and sacral cord are situated in the ii|i-
j)er ]iortion of this area, and in the lohidiis
jtaracontralis on the inner surface of the heiiii-
s|ihere.
The axones shortly after leaving the cells
give off collaterals \vhi(di Flechsig* has shoun
to be medullated. The axones of these nioidr
neurones all stream out into the centrum seini-
ovale, and run in the coroiui radiata of the in-
ternal capside. Arrived at the internal capsule,
they occui)y (at the level most freqitently de-
scribed) the genu and the anterior two thirds
of tlu' posterior limb of the internal capsule.!
The fibres at the kni-e of the cai)sule are those
which have come from the lowermost region of
the motor area (tibres governing movements of
the tongue and face) ; behind them are situated
the tibres of the middle region of the nioter
ari'a (fibres governing movements of the shoul-
der, arm, forearm, and hand) ; while iiiost
posterior of all are situated the tibres from the
u])permost portitms of the motor area (lihres
governing movements of the lower extremity).
From the internal capsule these medullated
axones are continued down through the base of
the cerebral peduncle, of which they oeeiiiiy
(roughly speaking) the middle three fiftlis, ;iiid
* Flechsig, P. rebor eino iieiie Fiirtiiiiigstiii'tlinilr
des eentraU'ii Nervensysteins uiid doren Firp'IniisM'
bcziiglieli di's Zusaininnnhaiigos von (Jaiiglioiizclli'ii iiinl
Xervpiifascrn. Arch. f. Auat. u. Piiysiol., l'liy>inL
Abtheiliing. Loip/. (lH8i)),S. 537.
•|- Lenticular segment of Dcjerinp.
•.it
(iUOl'IMNd AM) CIIAININC} T()(!KTI1HU OF NHl'KoNHS, <.>^l
then |ilmi<fo into tlio substiiiicc of tlio j)oiis, in!ikiii<,' up in it a
l!ir<;;o in'oporlion of tlio fasciculi lonj,'itU(linalc's of tliu pars liasi-
lai'is pontiri, boinf,' scparatod from the surface by the liltra' pontis
superliciales. In the midbrain and in the pons a luunberof the
axoiios terminate, (^omiujL,' into direct contact relation with tho
cell bodies and dendrites of the lowtT motor neurones situated in
the tuudeus nervi oculomotorii, nucleus nervi trochlearis, nuclei
motorii nervi trigemini, nucleus nervi abducentis, and nucleus
uervi facialis.* Some fibres go into tlie nuclei of the same side,
l)Ut the majority go into the nuclei of the opposite side. Tho
exact place where the fil)res of these nuclei leave the main bun-
dles, and the exact paths which they follow to the nuclei, have
not as yet been fully determined, but already a certain amount of
valuable information bearing upon these points has been obtained
{ride infra). The statement that nerve fibres from these bundles
do pass to these nuclei is based mainly, but not solely, upon clini-
cal ex])erience, physiological exi)eriment, and analogy.
As these axones pass through tho pons they give off numer-
ous collaterals which terminate in the nuclei jiontis.
Ficaving the pons, the axones are continued through the
Miedulla oblongata, forming there the well-known fasciculi pyra-
iiiidales, which correspond on each side to the pyramis niedullje
oblongata*, as seen from tho surface. Tho fact that the fibres in
the cord rej)resent the continuations of those which make up the
pyramids of the medulla oblongata gave rise to the name " jiy-
ramidal tract." This term was not derived from the j)yramidal
cells in the cerebral cortex, as some have erroneously thought.
In tho medulla the bundle of axones on each side diminishes
in volume owing to the exit of fibres which run to the groups
(if cell bodies and dendrites of peripheral motor neurones situ-
ated in this region — namely, to the nucleus ambiguus (nuclei
motorii glossopharyngii, X. vagiet X. accessorii) and tlie nucleus
liy[>oglo.ssi.
In the lower part of the medulla oblongata, just above the
cervical cord, the majority of the fibres of each bundle cross over
to the opposite lialf of the neural axis, giving rise to the well-
known decnssatio pyrmnidum (Fig. ()'-i+). This decussation does
* We have alrcudy n-ferrod to, mid sliall farther oti nj^aiii point out, the
I'lict tliat filircs to tlic nuclei of tlie motor corolmil nerves are, strictly speak-
ing, to be scpiinited from the filires going t<> the spinal cord.
V
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IMAGE EVALUATION
TEST TARGET (MT-3)
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982
THE N'HRVors SYSTEM.
not occur all ;il one s[)()t, but extends fur a distiitice of about
one cm., taking place in successive bundles. The fibres \vhi<li
cross from one side to the
other plunge through the
gray nuitter of the ventral
horn into the lateral funicu-
lus of the opposite side, giv-
ing rise to the fasciculus
cerel)ro - spinalis lateralis of
the opposite half of the spi-
nal cord. A certain ])ropor-
tion of the fibres ih) nut
cross but go down on the
same side of the cord, the
majority of them in human
beings occu])ying a region of
the ventral funi(uilus, form-
ing the so-called funiculus
'^erebro - spinalis ventralis.
Some of the fibres, however,
run down on the same side
in the fasciculus cerebro-sj>i-
nalis lateralis, so that in the
spinal cord the fasciculus
cerebro-spinalis ventralis is
an uncrossed bundle, while
the fasciculus cerebro - spi-
nalis lateralis is in the main
a crossed bundle, but con-
tains a certain number of
uncrossed fibres.
tpya,
Fl(i. (K4. Sclicmc sliii\vin« the dccussiitii)
pynmiiduin ut llif Inner part nf" the
uicdiilhi ohliiiiKatii. ( Al'lcr A. van (ic
liuclilcii, Aiiatimiic <lii systt'iiic iicrvcux
(Ic riioimiK', 1S<I7. Fit;, rwij), p. sil.)
flti/ii. t'asciciiliis (frcbni-siiiiialis ven-
tralis: ./)*,'/'. fasiic'.his (•(■rcli)i(-s))inalis
latcniiis: iin. nii;lcns aniliijjuiis: ».v,
iincli'iis ala' ciiicrcii' ; «. niiclt'iis oliva-
ris inl'cricpr ; /<(■/. corpasrcstirornic ; jii/.
I>yniniis nirdiilla' oljIonKatii' ; .V. N.
ViiKUS ; A7/. N. liypiitrl')ssns.
There has been a great deal
of discussion during the past
few years concei-niiig tiic de-
cussation of the i)yrauiitlal
fibres. The view {generally held until recently was that all of tlif
fibres of the lateral pyramidal tract were crossed fibres wliich termi
nated in the ventral horns of tlie same side, and that all of the libies
in the ventral tract (direct pyramidal tract) were uncrosst>(l lihres
which, however, crossed immediately or shortly before tlieir termi
luition by pa.ssing through tlie ventral white commissure to cud
•Wii
l^^'l
^mmm
MHP
(iUOUI'INU AND CUAININCJ TOOETllKIJ OF NHl'KOXHS. <»S3
of abtnit
I'os whicli
k' to the
oiigh the
e voiili'.il
111 fimicii-
t^ido, '/\\-
fasi'iculiis
iteralis <il'
if llie s)H-
in propoi-
's do 111 it
n oil tlu'
cord, till'
in liuinan
a region of
iliis, forni-
funiculus
vi'iitralis.
4, however,
.same side
erebro-spi-
liat in the
faseieuliis
entrails is
idle, while
rebro - sjii-
the inuiu
but con-
iiniber of
nrcatdeal
J,- the past
iig the de
pyramidal
all of til.'
lich ternii
f the libri's
ssed lihri's
lieir tfi'MU
lire to end
in tlie ventral liorns of the opposite side. According' to tlii.s
view tliere was, therefore, ultimately a complete decussation of the
pyramidal tract fibn^s ; that is to say. all the fibres from the pallium
to one side of the spinal cord came from the opposite half of the
brain, a view wliich was supposed to agree entirely with clinical
observation and i)atholofjical findings. In 1881 and 1882, however,
Piti-es found, after unilateral cerebral lesion, besides the degenera-
tion in the opposite lateral tract in the cord (heterolateral bundle), a
feeble degenei-ation in tlie fasciculus cerebro-spinalis lateralis of
the same side (homolateral degeneration). In an article published
in 1884 he makes the statement that his bom(dateral degeneration
could be made out in no less than ten of forty cases. These studies
of Pitres have been confirmed by other patbologists. In addition,
a large number of e.x))erinients on animals are in agreement with
his observations; thus Franck et Pitres, Moeli, Sberrington, Mel-
ius, P^iirstner and Knoblauch, Unverricbt and Kusick, Sandmeyer,
V. W. Mott, Muratott'. Rothmami, Wertheimer, and Lepage, after
<'ortical lesion experimentally i)roduced, have studied tlie cord for
secondary degenerations. All are agreed that besides the abundant
heterolateral degeneration more or less homolateral degeneration
also occurs. It is to be remembered, however, tliat in the animals
below man, .so far investigated, except in the monkey, no ventral
pyramidal tract exists ; all the pyramidal tract fibres of the cord
must run down in the lateral funiculus, and it has been assumed
that the fibres wliich degenerated homolaterally in animals cor-
respond to the fibres which in man run down in the ventral funicu-
lus. Hallopeau's suggestion that the degeneration of the homolat-
eral bundle depended upon pressure ett'ects exercised by degenerating
fibres of one side at the level of decussation in the medulla, lias
been supported to a certain extent by the experiments of Rothmann.
This observer, operating upon a dog and a monkey, found, after uni-
lateral lesion of one motor zone, degeneration always in both py-
ramidal bundles in the spinal cord in accordance with what had
been established by previous investitrators. He states, however, that
tlie dej^eneration is permanent in a crossed track, but in the homo-
lateral bundle is temporary, lasting only about two months — that is,
as long as pressure eH'ects would probably be exerted at tlie level of
pyramidal decussation. The honudateral degeneration in man,
howev<'r, is permanent, but Rothmann sugsifests that this may be
the result of defective nutrition, since in human beings sponta-
neous cerebral lesions are. as a rule, of vascular orijjin. and the nu-
trition of the brain may be insuflicient to repair the lo.ss in the
homolateral fibres accidentally iiroduced by the pressure at the level
of decussation in the medulla. The ingenious «'xperiments of Wert-
heimer and Ti<'i)age make it. however, seem probable that in the
fi i
0cS4
TIIK NHUVOL'S SVSTKM.
' ""', ■.-
(
1
i
I
i
v. ,
!|;-:,
i,.
.^.i.:
S
dog tlicro are actual hoinolatcral fibres in tlic lateral culuiim
Tliey found that after cuttiiij,'- tlir(>uj,fh the left half of the cervical
conl excitiitioii of the motor area in the right coi'tex UhI to move
meiit of tlie extremities of the riglit side. In the second i)lace
when tliey cut through the left half of the medulla ahov*; the nyr.-.m-
idal decussation and again stimulated it, the motor area of the
right side, they could produce movements in the left liind le<>-.
Again, on cutting through the left half of the cord below the de-
cussation at the level of the first cervical nerve, movements in (he
right h'g could be produced by electric stimulation of the si'nnoid
gyrus. To answer tlie objection tliat instead of innervation of the
right foot by homolateral fibrer. tlie <"onnection might be made bv
fibres vvlfich crossed twice between th»^ two planes of hemisection
tliey made a h)ngitudinal section of tlie medulla and found tliat
excitation of the motor area on tlie right side was still followed l)v
movements in the right hind foot. While the objection with regard
to pressure effects at the level of decu.s.sation must be carefully con
sidered, the evidence, 1 think, is, on the whole, .suflicient to justifv
the statement that both lieterolateral and homolatei-al fibres exist
in the spinal cord, Ix^th of man and animals, ' . the fasciculus
cerebro spinalis lateralis. Indeed, it would be surprising, when one
thinks of it and considers the nature of the impulses which set out
from the cortex, if such a double-sided innei-vation did not exist.
The fasciculus cerebro-spinalis lateralis occupies in tlie cer-
vical cord the large area in the postero-niedial region of the
lateral funiculus. It diminishes rapidly in volume as it descends
the cord, being very much smaller in the thoracic than in the
cervical, and in the lower lumbar than in the thoracic cord. In
the lower part of the cord it comes to lie adjacent to the peripli-
ery, while in the cervical and thoracic cord it is separated from
the periphery by the medullatod axones which go to make up
the fasciculus cerebro-spinalis previously descrihed.
The diminution in volume as the cord is traversed depends
upon the fact that at the diiferent segments constituent fibres of
the bundle turn into the gray matter to end there. The greatest
loss, as one would expect, occurs in the region of the cervical and
lumbar enlargements in which are situated dendrites and cell
bodies of the periplieral motor neurones which govern tlie move-
ments of the upper and lower extremities respectively. Helow
the lumbar enlargement the number of fibres is small, but a
certain number can be traced to the lowermost portions of the
sacral cord.
The fasciculus cerebro-spinalis ventralis also diminishes in
m.i
'tfsii
(JH(»riM\(i AM) (lIAlNlNci T<)(}KTnKH oK NKUKONKS. <)s:)
voluiiio ;is the conl is desceiulod, iiiiJ in it too tlio loss is greatest
;it tlie levels of the cervicul enhirgenieut, tlie ftiseieulus being
entirely exhausted on tlie thoraeie eord. The statement that the
libres of the ventral pyramidal tract cross over just before tei'-
ininating through the anterior commissure to end in the ven-
GyruH foni icul us.
ram/rottfiilis ctiimiilir iiifeniii'.
Cnvuni se/ifi petliK i<U.
InDHl<i.
tJ-'
Fasciriihia hiiailiiri/i
l)lcJ/<(//.S'.
FiiKi'iculi iiiotiini lilt
aSr'
luicleos iti'irDiiiiii
mlf-
rvri'hrttlniiii.
Mi
luisririfli ft'i'i'hri>-
E'...
aiinitilrn.
;he cer-
of the
escends
in the
d. Ill
)eripli-
d from
ike u})
in
/■^M,'dHUatiilhH)iitl<'.i
of siiiii<r.<tli('ti<'
cnHfhtctiati iHith.
Fid. i\'2'i. — IIori/Diital section tliroifjli lir.iin at level of uii|)ermost ]>iul nf i;l'>l'iis
pallidiis; iiewlioni i>alie. iii\ capiit iiuriei raiidati ; tlio, tlialaiini>: ///,
laitaiiieii. .lust medial to the latter is seen tiie tip of the ^lohns i)alliihis
(niielens lentifonnis II'. i .Vfter P. Kleelisi),', Andi. f. Anat. n. Physiol.,
Anat. Abtii., J.eipz., ISSI, Taf. iii, Kij,'. s. i
tral horn of the opposite side, has been vigorously combated by
von Lenhossek. 'Phis investigator has made a careful study of
the sjiinal cord of two human embryos — one thirty-three, the
other thirty-five centimetres long. He states that he could never
find axones fr in the ventral pyramidal tract entering the ven-
tral commissure. He believes that they all run in to terminate
in the gray matter of tlie ventral horn of the same side ; that
is, that the path from the motor area of the pallium to the
ventnd horn cells is throughout direct and uncrossed. Van
<i('huchten has made the objection that at this period of devel-
(([iment of the human fo'tus the fibres of the ventral pyramidiil
tnict iire not present. If this be true, the argument of von Len-
hossek falls to the ground.
Hoche with Marchi's method finds that the fibres of the ven-
tral pyramidal tract end jcirtly in the ventral horn of the same
side, but niiiinly in that of the opposite side (vide infra).
itsr.
TIIK NKltVolS SVSTKM.
¥
I ■
'im
'1^^
lit
rt-ttr:-^. -
Tlic fi)iir |iriiicijtiil iiictliods for iiivt'sti<iati!i<.'- tlie course ol'
tlin axoiu's wliicli ^{) to iiiakc up tlie pyniniuhil tracts arc (1) the
ciuhryoloufical inctliod of Flcclisiij; (:i) by jiliysioloifical cxpini-
inent, iiu:lii(iiiig elect ri^al stimulation and the likt^; (;}) ti,,.
inetliod of secondary degenerations, {a) occurring spontaneouslv
in luiinan beings as a result of disease; (/>) experimentallv pyn.
duc(Mi in animals by cortical extirjnition or by section of the
l)uiulles at some point in their course; and (4) the application
of the metliod of (lolgi.
The enibryological method of Fleclisig is especially well
adapted for the study of the fibres of the pyramidal tract, inas-
much as at birth, or shortly before birth, all the fibres of the
spinal cord have received their myelin sheatlis with the excep-
tion of these fibres; and in sections stained by Weigert's metliod
the positions occupied by the fibres of tlie pyramidal tract stand
out clearly and shiirplyas ])ale areas in the set^tion. This metliod
has been of particular service in demonstrating the asvmmctrv of
the decussation which often occurs in the human cord.
It is among the greatest achievements of Fleclisig * that he
has traced out with the strictest accuracy the position of the
axones of the pyramidal tract and the corresponding bundle of
fibres for the innervation of the nuclei of the cerebral nerves, all
the way from the cerebral cortex nearly to the termination of
the fibres in the groups of cell bodies belonging to the lower
motor neurones. The course of the bundles, as outlined Ijv iJiL'
embryologiciil method, will be clear if F'igs. G25-0;]l with tlieir
legends be consulted
The serpuMK e of niedullation in the sensory and motor lihics
* Fk'clisij;, 1'. reluT ciiiige Beziehuiij;eii /wisclicii si'diiuliiri-n Di'trciiffa-
limu'ii iiml Kntwicki'liiiij^fsvorf^iiiij^eii im 'iienscliliolieii liuekciiiiiiirk. Aicli.
(1. Hcilk.. licipz.. I$(l. xiv (IHTJf). S. 4()4-4()!l.— Dio lioitimj^'shahiu'ii im Gchiin
iiiid KiU'kciimark des .Monseheii auf (iniiid (■nt\vicki'luiigsj,'i'sc'hiclitli(h( r
I'litcrsuchuiifji'ii (iargcstellt. 8vo, Leipzig (IHTd). — ffher " Svstem-Krkiaiik-
imgcn " iin Kiickciimark. Arch. d. il(>ilk.. lii'ip/.. IM. xviii (IS77), S. 101 ;
'JHJt; 4(J1; ami Hd. xix (1878). S. W: 4-11: (Viitralbl. i. die iiKHliciiiiscli.ii
Wisscust'haften (1877), Nr. ij. — rebcr die ("apsiila interna. Tagchiutt dcr
Natiirf")rsclii'r-\'('rsammiuiig. .Miiiiclicii (1877), S. 2^6. — '/aw Anatomic iind
I'jitwicki'lungsgi'scliichli' dcr licituiigsliaiincn im (irosshirn dcs Mciischcn.
Arcli. f. Anal. ii. IMiysit.l.. Anat. Abtli.. i.cipz. (1881), S. 12-75.— Plan dcs
mcnschliclicn (t(4iirns aiif (timiikI cigciicr rntcrsuciuingcn cntworf
licipz.. 8v(i. 188;i. — (ichirn und Seclc. Lcijizig (18i)0). — I»ic liocalisatieii i
gcistigcn Vorgiinge, Leipzig (I8i(6).
CM.
f
k
(;H(>riMN(i AND CIIAINMNM} TOdKTIIKi: OF \Kri{()\KS. »),s7
is (lilTorent as regards the neriplu-nil neuroiu's from that, which
concerns the central neurones. Whereas the uxones of the
|ierijtlieral motor neurones of the spinal cord and inedulhi
(ihlouirata are medullated before tlie axotu's of tlie peripheral
sensory neurones, tlieaxoiu'sof the upper motor neurones — that is,
those extending from cell IkmHcs in the pallium to the nuclei in
tljIvtmfrnyifiiUn
hifiriiir.
IllSltlll
I 'llllSlllll ('.(•<('("»((.
Piirs /n>itttili>i fiiiisidit inlirnif.
1
I'usiiruli ri'vrbninphiiih'ii
(I'l/nm triiijiordlin ^
miiwriar.
('iiiiild iniiiri rintddti
Ciiiml iincli'i ctiiiildti.
\'fittn'<'nhin Idfrnilin
(('((/•(III (lli/cc/K.s).
Fiiriii.r.
Ftmtiiithis hd^ildrin me-
(liiilifi dnil liiiiiilh' (I,
7Vi(//((((ii(ji.
ydsiifiili motdiii nil iitiflios
(iirniciim cvrebraltiim.
I'ids (i(ri/)i7((/i.s' rdimuliv intrruir.
Tifiineittdl riulidtion.
I'lii. (i2l>. — Iliiriitiiiital .scctiiiii tlinniKli liriiin <it' iifwliorn l^ilic almvc level of
tiiiist niediiil sefinieiit of nucleus leuliforinis. (After I*. KleelisiK, Arcli.
f. Auiit. u. I'liysiol.. Auat. Aldli., I.eipz., 1881, Tiif. iii, Via. 7.) II, kIoIius
)ialli(lus; ///, iiulanieu. Natural size.
which are situated the cell bodies of the lower motoriiouronos —
liecome medullated later than do the axones of the central
sensory neurones extending out to the cerebral cortex. In other
words, in the cerebral white matter the sensory (centripetal)
projection fibres are medullated before the motor (centrifugaJ)
projection fibres. The medullated axones of the pyramidal
tract pass out, in the main, from that region of the cerebral
cortex which, according to Flechsig, corresponds to the distribu-
tion of tlie sensory axones of his system No. I (ride supra).
These fibres, origimiting in the large pyramidal cells of the
lobulus paracentral is, and the anterior and ])osterior central gyri,
converge in the corona radiata to enter the internal capsule.
The position of the fibres of the ])yramidal tract in the
internal capsule varies, as the figures show, act'oi'iling to the
level of the capsule studied. In the level most frequently referred
to by clinicians, the })yramidal tract fibres occu})y the anterior
i
1;
' Ij
I'
-.r
Mi 4'i
<>ss
TIIK NKI! vol's SYSTEM.
11'*
J ■«'
L
two thinls of the jioslci-ior limb of tlu' caijsiih! ; that is, tlio so-
<'jilled thahiino-lonliforni portion. Arriving in the internal
('jipsuU', tlicse buniUcs cciisc to hv sc^paratcd bv libri's of aiiitTi'r(Mit,
naturo, and bt'conic aggregated in tlio form of a tolerably compact
Liimiuii mciinlUiria. ..J
n
J.dlllhlll UK"-
(liillin in.
Ldiiiiiiii me-
(Julia ris.
Fascirnli ..
ivrfhro-
Kliinaleii
in ■
l''/l'(llsi(/'H
1'eijoiintiil rdilidtinn
Auflfiix <-aii<l(iliis.
Meihilhitiii liliri'ii I'nin
ansa Irtiticiiluiix i -i
FdKCicillu.i hll.li-
hfriH mi(//(i/i.<.
Fiixrii-iili tliiihi
)iiii jiiillitili ^,
Fimriiiili iiiii
!•-" tofii (III /III
ii'ijn )ifrr(iriiiii
ci'rcliniliiiin.
Mxliilhilcl
IiiiikIIis III
zona rcticiiliiris.
Nucll'll.'i Inter
alls thnhlliii.
Thdhtmua.
Son-mtdiillitti'd Innidles of occipito- , ' ' l^i.-j. ' -.'
thdldiiiic nididfidii.
Fl<i. (W7. — Horizdiital scctiim tlifiiii};li lippcrmiist portion oCiii('(lial scKiiiciit of nu-
cleus Icutil'oiiiiis ; lifwlporn lialx', .">() to .')I cm. loiifi. ' After 1'. I'"leclisij;, Arch,
f. Anat. 11. I'liysiol., Anat. Ahtli.. I-eii)/,.. issl, Taf. iii, Fij;. (i. i /, //. fihihn^
pallidas ; ///, piitanieii ; »/, coiitimiotis with d of Fif;. (Wi. Mufjuifieil fmii'
times.
fasciculus, which passes first between the nucleus caudtitus and
the nucleus lentiformis and farther down between the thaluniiKs
and the nucleus lentiformis, to enter the cerebral peduncle. At
(ilioriMNd AND CIIAININMJ T(»(JKTII Kli OF NKUUONKS. <»,s',»
!il)()iit the junction ol' tlio iiilcruiil cuitsiile with tlio corchral
])0(luiiclc the libres of the })yiiiiiii(liil traot are interwoven witli
transverse bands of llbres, wliioh be(3onie niedullated at a period
later tlian tliat of the niyelinizalion of tlie pvrainiihd tract.
Tills interleaving begins at a level corresj)ondiiig to the dorsal
border of the nucleus hyiiothalaniicus (corpus Ijuysi),and extends
downward as fur as the posterior and ventral extremity of Luys'
body. These transverse fibres rumiiug through the pyramidal
tract at this level represent in the main the tibres of the ansa
lenticularis. On its way through the internal cajjsule the j)yrani-
idal tract is separated from the thalamus by a medial layer of
,y^<i'',T\. ,
Liimimt mvdiillaris.
Laminti meditllarin
lUtilUil mi'il\ill(iti'il Inm- ..
till .1 in iiiicli'its lenti-
fdriiiis.
1,(11111)1(1 mcdtil-
Idria.
./"
.llixrl leiiticil-
larin.
•<.IU;,j^>'
Fasciculus Ixisi-
liirix mcdidlis.
Fiixciculi niotd-
rii 11(1 11 uclco.i
... nervorum
cerebral ium.
Fii.'iciculi cerc-
bro-s/iiudlis.
Hypothdhimus.
v.cierna.
y
RdiUdtio cnrporin (jenicidatl tncdidli.i.
V\(i. (i^H. II(iri/(nitiil scctidii tlinni};li l)iain of liiilx', .'iOto.')! cm. Ikiik, at level
of lower third dI" tiisl portion of iiticleiis leiitit'oriiiis. ACter I'. l''leelisiu,
Arch. r. .\iiat. u. Physiol., Aiiat. Alilli., l.eip/.., IHHl, Taf. iii. Via- 3.' ",
coiitiniiatioii of fasciculus Uasilaris lateralis; </, til)res couliiiuoiis with (' of
I'Mk. ()"^7 ; e. tiiediillatecl tihres e.Nteiidiii}; lietweeii hy|mthalaiiiic rejiion and
nucleus Icutifovniis ; /. lihres of c which have [lassed through the capsul.i
iuteriia ; /„ nucleus hypolhalaTniciis (corpus Luysi ) ; /. //, fjlohus ])allidus ;
///, putanicn. Majjuilied four times.
It. !
white matter (medidlated tixones of sensory neurones extending
t)ctwcen the dienceplialon and the pallium).
Tn the base of the cerebral ]>edunole, too, the position of the
pyramidal tract varies according to the level examined. In tlie
: I
i
Wi)
Till-; NKHVOIS SYSTKM.
m
:
lii<,flier rc'gioisof the base of tliu podiiiu-lo (or poa) the pymiiiidal
tract occupies the third, fourth, and fifth, reckoned from tiie
medial side, wiiiUi lower down it occupies about the nuddle third
of the base of the peduncle. At the junction of the cerebnd
peduncle with the pons the fibres of the pyraniidul tract split
up into several bujidles and help to make up, in lar<fe part, the
fasciculi lon<,Mtu(linales (pyramidales) which run through the
pars basilaris pontis. At the lower end of the poi'is these longi-
tudinal bundles unite on each side to form the compact pi/rami.s
which occupies the ventral surface of the medulla oblongata,
close to the fissura mediana ventralis. In the medulla the
majority of the fibres of the pyramidal tract as shown by the
developmental method pass over to the opposite side of the
nervous system forming the decussatio pyramiduvi. 'I'he large
crossed bundle passes down as the fasciculus cerebro-spinalis
lateralis through the lateral funiculus of the spinal cord. The
/Fasciculus Ixmilaris lutfriilh.
Tegtiieutum.
hrnrhium conjiinrlirum."
Suhslinititi lut/rti
Fd.iriritti rcri'lini-
Hin'lltllril.
F<iminili iiiottirii ail
iii/c/co.'.' ni-rviiruiii
rerchraliiim.
Fdsciciihis htisildiix iiipiliiilh.
I"l(i. ():2!t. ycctioii at riKlit annlcs to the loii^itudiiial liliivsof the t)asis pcdf.ciili
.jiinclidii of U))iirr witli iiiiddlc tliird) : iH'wlxirii halu', 50 to 51 cm. loii^'.
Sliillci's lliiiil liardcuiiiK. Mmiiitcd in fjlyccriii. (After 1'. l^'lcclisi};, Anli.
('. Aiiat. u. I'liysiol., Anal. Alilli., Lii]i/,.. ISSl. Tat', iii. Fij;. 1.' //. riiii>l
hiti nil linndlt of llic loi's;!! si rain in of the lia.-is pcdniicnli ; d. nonincdn Haled
lilires in diii'siil siralnni ; x, isolated l)iindles of niednllaled lil)res, naliiic
nndeterniin((l. >[a.!;nilied four limes.
I-
smaller uncrossed bundle, consisting of the lateral portion of the
pyramis,* passes down as the fasciculus cerebro-spinalis ventralis
of the cord.
It is of intiircst that liurdach was able to niaki' out tliis jioiiit.
Kt%.
(JUOriMNC, AM) CIIAININC TOCKTilKIf OF NKl'ItONKS. \y.)l
Fleclisig has studied tho decriissutio pyniiiiiilutn iiiid its vuriu-
tioiis witli grt'ut euro.* In about fifty per cent, of all wcll-studiud
Sulriin mf<ti<iiinn diiixiiU^
yuariciiliid ijritrilis (.(lulli).
t'liidi'iil
tittrillli.t
/•'iinficnlns vciitnilis jiri>i)riii\. lioilix vi-ntidlis.
/•'((.i'ci('i(/i(.< cfn'hrii siihiiiliH vent ml in.
I'l(i. two. — 'ri-imsvcrsc section tlinmj;li tlic s|)iii;il CDnl of a ii('wl)oni Imlic, alxiiit
50 ('111. loll};; level of sixth eervi<'iil nerve. Oold pri'iHinilioii. (.Xl'ter P.
FleclisiK. I>ie Leitiiiinsl)aliiu'ii iin (ieliini iind IJiickciiniark, I.eip/... IHTti,
Taf. xi.\, Fiji. 1.)
cases the distribution of the pyramidal tracts is asymmetrical.
TluLs, ill a certain number of instances, all of the fibres go down
in the lateral pyramidal tract and there is complete absence of
the ventral pyramidal tract on each side. In these cases Flechsig
assumes that the decussation is total. f In other cases he finds a
* l^'loc'lisig, P. Die lieifungshahni'ii iiii (Joliirn und Hiickeiiinurk des
Mensdicii, etc., L. ipz. (1H76). S. 270 c/ my.
t From the studies of ex|ieriniental dej^eiieration to be ilcscribed farther
(Ml we iKiw know that many of tlie fibres whiidi I'lin down in the lateral
|iynimi(hil tract in the spinal eord are uncrossed fibres. It is therefore not
improbable, that these cases of ajiparent total decussation are in reality not
siicdi, but simply instances in which the uncrossed fibres all j:;() down through
the lateral tract; in monkeys this is the normal condition since the monkey
[xissesses no vcnti'al pyramidal tract, and yet he is not unprovided witli
direct (uncros.sed) pyrauiidal fibres.
H
^mWt\
I
*i
I
TlIK NKIfVolS SVS'I'KM.
r
\U
hV
m
vc'titnil pyramidiil tract on one side, hut iiorio on the other. In
other cascH there is ii vciitriil i>yriinii(hil tract on Ixitii sides and
in tiiese cases the number of libres in tiie ventral tract of one
side as compared with the number of tihres in tiu' lateral tract
of the opjjosite side, and again the relation of tin; number of
fibres in the ventral tract of one side; to the number of fibres in
the ventral tract of the other side, can vary within considerable
limita. Flechsig concluded that the fibres arriving from a
definite region of the cerebrum through the pyramids into the
spinal cord may take either one of two courses, ruunin<r in the
ventral pyramidal tract of the same side, or in the lateral pyram-
idal tract of the opposite side.
Fltchsiy's " ciiitntm ofiilc
Fitsririihis ciinetitm {Uiiitiurhi).
A'df/i'.r rentnili.i. Fdsriiiilu.i reiitriilis propriun.
Fid. (>;51.— Tnmsvcrsf scctidii tlirou^'li tlic spinal cord of a ncwljoni halw. about
.'JO cm. loiiK ; level of t'ourth Ininliar nerve, (iold preinuiitioii. (.M'tcr I'.
Fleciisif;. Die Leitiin{,'slialinen im (ieliirn nnd Riickeniiiark. Leiiiz isTd
Tal'. xix. FiK. 2.) ' '
The area occupied by the pyramidal tract decreases from
above downward as the spinal cord is descended, owing to the fact
that the medullated axones are ever running in to terminate in
the adjacent gray matter apparently in the ventral horns.
The fasciculus cerebro-spinalis lateralis, or lateral pyramidal
(!l!(iri'IX(i AND CIIAIN'INO T()(JKTIII<;i{ (»!•' N'KriioNKS. «»<.»,*{
triict, lios iilwuys in tlic postoridr Imlf of tlic fiinidulus liiU'nilis.
Flt'C'lisip states tlmt tho [Ibrcs never extend further forwunl than
an irnM<,'inary stniij^ht line drawn latcralward from tlio (jroiii) of
cells known as the colunina intennedin-lateralis. 'I'lii' cnibrvo-
loifical method permits one to follow tiie lateral pyninudal
tract downward as far as the lower end of the lund)ar enlarj,'e-
iiient, or even to the level of the third or fourth saerul nerve.
As i('<."inls the relation of the lateral pyramidal tract to the
peripiiery of the cord, this varies considerahly at dill'erent levels.
Thns, at the level of the third cervical nerve it reaches, as a rule,
to the surface of the posterior part of the lateral funiculus, even
conung in contact with the pia mater. In the cervical enlarge-
ment the lateral ])yramidal tractt is separated from the j)ia mater
hy the com])act bundle of the fasciculus cerebelht-spinalis of
Flechsig (direct cerebellar tract). From the middle of the tho-
racic cord downward the dorsal portion of the lateral pyramidal
tract reaches the periphery, although the ventral part of the lat-
eral surface of the liundle still remains separated from it. In
the lower portion of the spinal cord the lateral pyramidal tract,
now grown small, is situated close to the periphery of the cord.
The fasciculus cerebro spinalis ventralis,* or direct pyramidal
tract, lies, as a rule, on the medial surface of the ventral funicu-
lus. The area in cross section is variable. It may extend from
the ventral commissure as far ventralward as the ventral margin
of the fissura niediana ventralis. In other instances it occupies
the dorsal half or the middle third of the medial surface of the
ventral funiculus (Flechsig). its kmgitudinal extent in the cord
varies much. Sometimes it ceases even at as high a level as the
middle of the cervical enlargement. In other cases it extends to
tiie upper thoracic or, most commonly, to the mid-thoracic cord.
Occasionally it has been followed as far as the intumescentia
limibalis.
Fmx'TUIcai. Stimilatiov. — A great deal of our knowledge
regarding localization of tlie cell bodies of these upper motor
neurones in the cerebral cortex has been obtain >d through j)hysio-
logical experiments, and especially by means of electrical stimu-
lation of the cerebral cortex. f We are indebted especially for this
* This was (lcsc'ril)e(l by Charcot as Uw/diwcdu dt- Turc/c.
\ It is surprising how .1. IIuf;hliiigs .laeksoii, Ijy means of clinical and
tpathological observation and a happy scientific imagination, arrived at very
important conclusions concerning localization, wliich have since been in
ll
1
t
1
1
k
!»!»4
TIIK NKKVOlS SVS'l'KM.
iiilvancf to the rcsciin'lu's of Kritsch aiul llitzii;* (1S|()) wjili tli,.
j,'iilvaiiu^ c'lirri'iit, ami t'S|n'cially to tlic brilliant rcsulis t)l)iaiii(i|
by I'Vrricr t (1ST;>) on faradic excitation of tlic ci'rcbi'al cortex.
Tbc ('X|K'riiUfnts (if {'"ritscb anil 1 1 it/.ii; sliowctl that stiniiila-
tion of certain n ,_;it)ns only of tlie brain lead to movements of
|iarts of tlie body, and tliat between tbe j)la(H> stimulated and I lie
part of tlie body set in motion strictly detinite relations exist.
'I'lie idea of a so-(!alled motor cortex tluis arose.
'I'lie experiments of I'\'rrier proved tliat on suitable excitation
of tbe surface of tlie cerebrum witli tlie faratlic current move-
ments can bo called fortli wliicli po.ssess a delinitely purpo.setiil
character. In other words, moveimuitsof the individual parts of
the body are evoked which correspond to tlio.se actuallv carried
out voluntarily by an individual in the cour.se of his ordiuarv
bodily activity. With similar methods l'\>rrier was able to local-
ize L'cncrally the principal movements of the face, ai'in, trunk,
and le>:; in the monkey.
The ijeneral electrical experiments on the cerebral cortex weic
carried out with aililitional reliiiements by Ilorslcvand Sciiaefert
I
V I
larijo ])iirt coiiliniic'd hy |iliysii)lo!j;ists ami iiiialomists. 'i'o lu' ('(iiiviiicctl ef
tin- woiiili'rfiil foresight (if I ln' writer (iin- lias (inly tucciiiiimrc pn'sciu kimwl-
t'lli^t' with \U{\ liypdllit'st's wliicii he inlvaiiccd in tin- t'ollowin:,' uriiclcs:
Xdlc:, (in (111' !Miysitiliii;y and I'atliold^y ef Ijanfiuaijc : Ui'iiiarks mi tlniM'
Cases of |)is('as(( ef the Ncrveiis System in wiiicli Dcfccl df I'A|ircs.>.ii)ii istlu'
most Strikiiitf Symptdm. Med. 'rimes and (in/.., Ijond. (IMOd), i. pp. (irilt
tUi2. — On Iidcali/atidii. Med. Tinu's and (in/., liond. (ISdit). i, p. (iUU.— On
tile .Vnatdiiiical and i'liysidld-jical Ijdcalizalidii df Mdvcmcnts of liic Uraiii.
iiancct, Iidiiil. (IH7;!l, i. pp. S4 ; 1(!2; '2'-\'2. — Oliservations dii the lidealizatidii
of Md\(Mneiils in the Cerclinil Ucinisplicrcs, as revealed liy Cases of Cdiiviij-
sidii. Cliorca, and .\pliasia. West Uidini; liun. Asyl. Kep., l,diid., vel. iii
(1HT3), pp. ITri-l!)"!. — Cases (if Partial Cdiivnlsidii fidm Or^^aiiic Urain Dis-
ease, iiearinjj on the l"]xperiments df liitzi^jaiid I'Vrricr. Med. 'rimes and
C.az., l.diid. (1875). i. pp. 'uH; ()()(); (i(iO ; ii. j p. '..'(U ; ;i;!(); (IHTtI). i, S.
* l''ritseli, (!., and E. liitzi,!;. feher die eleklrisclio Mrrcf^liarkeil drs
(Jmssliii'ns. .\rcli. f, .\iial. i'liysicil. n. wissonseli. Med., l,eipz. (187(1), S.
;{()()- :;:w.
f Kerrier, 1). Tlie Ldcalizatidii nf Fiinelidii in the IJrain. I'nic. Unv.
S(H'., Lond., vol. xxii (187;5-'7i). pji. •J'Jit ',';!','. — The Cnidinan liectnre: V.\
periiiieiits on (he Mrain ef Monkeys. Phil. Tran.-. Koy. Sdc., !,ond., vdl. clw
(1870). pp. •i;i;{-48H.— The l''iinetidn .if the Mrain, 'Jd ed., b.ind. (l8St!), p.
.VJII, 8vd.
\ iidrsley, \'.. and 1']. .\. Schael'er. A Kecdnl nf Mxperiments iijioii I lie
l''iinetidns df the Cereliral Corlex. I'liil. Trans. Udy. Sdc., bdiid., v.iI.cIxmx''
<IH88) (H.), pp. l-4r).
<n{()riMN(i AN'I» CIIAININO TOOKTIIKU OF NKl'llONKS. «»l)r>
uiitl l)y l?t'('Vt)r aiul llorslt v.* At jn't'scnt it wcMild soom us tliouirh
tilt' results witli roj^iiril to tlio moiikcv's cortex luv as porfei.'t as
till! iiiiiitatidns of tlic iiiL'tliods permit. Siiioo the monkey's
cortex, luul cspociiiliy that of tlie oraiig-oiitaii<;, so closely re-
sembles that of man, these results are of the iiij^hest importance
for the physician and surgeon. Over and over again it lias been
possible in human cases to localize with great accuracy the exist-
'ence of an irritative lesion in the motor domain of the cortex,
and in many instances surgical interference has been resorted to
with success. (H" course the improvements in the techni(pie of
brain surgery in recent times have resulted in the mor«' fretiuent
resort to opt^rative interfereniie on the brain of human beings, so
that it has been possilile in (piite a notable number of instances to
<!arry out actual electrical excitation of the human cortex, owing
to which we already possess a certain amount of dellnite inform;.-
tion regarding localization in the liiiman cortex, which has been
obtained directly {vide infr<i).
Heevor and llorsley (18S7) decided, from the results of their
experiments, that the anterior central gyrus is much more con-
<'crned in the motor (inu.'tions than is the jiosterior central
gyrus. They concluded, too, that in the area of motor repre-
sentation for the iippi'r limb, the ri'gions for the larger joints
are at the npper parts of the area, while those for the smaller
joints and more diU'ereiitiated movements lie peripherally at the
lower part of the area. 'I'he movements of t'xten.^ion, they be-
lieve, are reiireseiitt'd rather in the upper j)art of the area, while
those of flexion appeared to be related to the lower part. In
between these two areas is situated a zone of confusion (Kig. iVM).
In their earliest experiments they studied not only the primary
movements which result from eU'ctrical stimulation, but also the
subse(pient " march " of the movements as the electrical stimulus
becii-Mc dilTused through the cortex. A remarkable correspond-
* Hct'vor. (". M., and N'iclor II(itsl(>y. A Miiiiilc .\iiiilysis (oxpcriini'iilni)
of I lio Various Movi'incnls pniiliiciMl l>v Stiiiuilali'ii; in tlic Moiikoy Oiffcr-
ent Ht'fridiis of the Corlical CiMitiv for tlic ri)|i(',- Ijinili as Dciint-d l)y Pro-
fessor Kcrricr. I'liil. 'I'rniis. Uoy. Soc. Iiond., vol. clxxviii (IHH7) (M.). pp.
ir);{-l(J7. — A Hcoord of (lie Hi'siilts ol)tain(d t)y I'lliM'trical Kxcilation of iln'
So-calli>d Motor Corti'x and Internal Capsule in t lie <lraii};-Oiit an j;(.SV/»iVt
f«i/i/nix). IMiii. Trans. |{oy. Soc.. I,ond.. vol. cixxxi (1H!)0) (15.). pp. fJiJ-l.lH.
.\ Further Minute .\imlysis liy Fieetrieal Sliniulalion of tlie So-called
Motor l{efj;ion (facial area) of tiic Cortex Cereliri in the IMonkey ( .'/(rcifc^.s
■siiiiri(it). Phil. 'I'lans. l{ov. Soc, i.oiid., vol. ilxxxv (IHlll) (M.i, pp. ;!!( SI.
6B
I
I
i
[■ : ,
«♦!»<;
TIIK NHKVors SVSTKM.
ciu-e was found between the progress of these marclies and tlic
farsiglited observations of J. llugliliiigs Jaekson in cases of
epilepsy, Fn l-'igs. T and H accompanying tiieir article the iihkIc
of march is clearly illustrated, and it is seen to be in liarmonv
with the representation of primary movements in the various
points in the area. 1'hey decided that there is no absolute line
of demarkation in the monkey between the area of localization
in the cortex of one movement and that of another, each move-
ment having a centre of maximum representation which grad-
ually shades off into the surrounding cortex.
Fi(i. (WS. — Early I'xiu'riinciits of Hccvor iiiid Horslcy at motor citcIhiiI locali/a-
tioii. (Al'trr ('. K. Hci'vcir and V. Horslcv, I'liil. Tr., I^oiid.. ISH". nl vii
Fift. 3. 1
These preliminary researches of lieevor and Ilorsley were
soon followed by the exhaustive studies of Ilorsley and Schaefer
(18S8), who attempted to localize centres for voluntary move-
ment and also for sensation by means of electrical excitation
atid ablation. In the prefrontal region the results of elect riciil
excitation were negative as long as the electrodes were ajiplicd
in front of the sulcus pra'centralis ; but as soon as stimulation
was applied beliind this sulcus these observers began to get
lateral movements of the head and eyes such as Ferrier liad
described.
The main motor area of the cortex as outlined by physio-
logical experiment includes a large region in the neighborhuoil
of the sulcus centralis Holandi. The motor cortex (jorrespoiuls
in the main to that of the two central gyri (anterior and pos-
tiy
(HIOUPING AND ("IIAININO T()(iETIlKll OF NKl'UONKS. <t<»T
tcrior) and tho lol)ulus paracoiitnilis, although stimulation of tlio
fwt of tlie three frontal fjyri as well as of certain other points in
the cortex may occasionally call forth a motor reaction.
Ferrier had found, as we have said, the princifial areas of
representation for tlie various movements of the fac^e ami of tho
upper and lower extremity. Hy stimulation of tlie excitable
portion of the lateral surface of the cerebral hemisphere lie
obtained (1) on the middle of the frontal lobe, movements of
the head ami eyes; (2) just behind this area on the anterior
central j^yrus, movements of the hand and arm ; {',]) on the pos-
terior central gyrus, movements of the fingers aiul wrist; (4) on
stimulation about the inferior extremity of the sulcus centralis
Holandi, including parts of both central gyri, movements of the
face, jaw, and tongue.
Horsley and Sch 'er described the arm area as occupying
a triangular portion of the surface, broad behind and narrow in
front. It comprises most of the ujjper half of the posterior
central and anterior central gyri (in the monkey) from a little
below the level of the sagittal part of the sulcus pra'centralis
below nearly to the margin of the herr.isphere above, together
with a small portion of the adjacent part of the frontal lobe.
The shoulder muscles react most strongly when the electrode is
applied lu'ar the superior limit of the area; while the muscles
moving the forearm and wrist come into activity when it is
applied near the central and inferior portions of the area, and
the muscles of the wrist and fingers react to stimulation along
the posterior border. It is signifi(;ant that these observers, like
all others who have experimented on the cortex, find that move-
ments and not individual muscles are represented here. The
facial area described by Horsley and Schaefer includes the area
(if representation not only for the movements of the facial
muscles, but also for those of the mouth, throat, and larynx. It
('(imprises the whole of the posterior central and anterior central
jryri, inferior to the arm area, extending downward as far as
the fissure of Sylvius and including the lateral surface of the
(iperculum. It is in the upper third or half of this area that
blinking or closure of the eyelids along with elevation of the
ilia nasi and retraction of the angle of the mouth are initiated.
This portion of the area they have therefore justly designated
tho " upper face centre.'" The lower third of the area, stimula-
tiiin of which is accompanied by varying movements of the jaw
mt
998
THE NERVOUS SYSTEM.
and tongue, some of them much like those of mastication, i ey
call tlie " lower face centre."
" The head area or area for visual direction corresponds to
un oblong portion of the surface of tlie frontal lobe extendiiiir
from tlie margin of the hemisphere, around which it dips for u
short distance oi.cward and somewhat backward to the upper and
anterior limit of the face area." It is bounded posteriorly by the
arm area and in front by nonexcitable cortex. On excitation of
tnis area they obtained opening of the eyes, dilatation of the
pupils, and turning of the head to the opposite side with con-
jugate deviation of the eyes to that side. Strong retraction of
the ears could frequently be elicited if the electrode was applied
near the angle of the sulcus pra?centralis.
The leg area {vide sup 'a) is situated partly upon the medial
surface of the hemisphere, but extends also over a certain portion
Diagram I.
Fig. 633. — Motor (•(■rctjnil locHlizatimi in tlic monkey. fAftcr V. llorsU'y :v'i'f
K. A. Sdiat'lVr, IMiil. Tr., J.ond.. !8HH, p. (i, (liu;,M-iiiii 1.)
of the lateral surface of the hemisphere occupying an area in
front of the tissura ])arieto-occipitalis almost as far forward as tlie
k>,t>
■%i
(juoi'pinh; and chaininc} Toui-yniKR ok neurones, djmj
level of the iinterior extremity of tlie small sulcus muikecl x iu
their cliagram.
Diagram II.
Fl(i, (134, — Motor ccrcln-.i! locali/atioii in inoiikcy. (After V. Horslcy ami ('. A.
SchiU'lor, I'liil. Tr., Loud., 1888, p. 10, (liugnmi 2.)
The trunk area is situated mainly on tlie medial surface of
tlie hemisphere, extending for only a short distance over the
margin to reach the lateral surface. The general results of their
findings are beautifully illustrated in the accompanving diagram
(Fig.o;5;5).
In addition to their careful study of the lateral surface of the
hemisphere, Ilorsloy and Schaefer extended their experiments to
the lobulus paracentralis and to the medial surface of the gyrus
frontalis superior. To give briefly their results on stimtdating the
excitable portion of this area on the medial surface of the hemi-
sphere, it may be stated that on applying the electrodes at succes-
sive points from before backward they obtained (1) movements
of the head ; (•■*) of the forearm and haiul ; (.'?) of the arm at the
.shoidder ; (4) of the upper (thoracnc) part of the trunk ; (5) of
the lower (pelvic) part of the trunk; (0) of the leg at the hiji ;
(7) of the lower leg at the knee; (8) of the foot and toes. It
I /
^'\
it.
KiOO
TIIK NEKVOL'.S SYSTKM.
I.
L
will thus be seen that in the monkey the lieud, arm, trunk uikI
U'<;[ are all re))resonte(l to a certain extent upon the facies niediulis
cerebri (Fi/:,'. (i;5+).
The j)hy.siological results of ablation in the motor areas i>\'
the cortex were quite in accord with the findings with regard u>
function as determined by electrical excitation. In this con-
nection the studies, \ot only of Ilorsley aiul Schaefer, but also
of Ferrier and Yeo, of SehiiT, Munk, Lueiani, and others should
be consulted.
In 1890 the results of an important research were publishcil
by Heevor and Ilorsley in which appeared ineir fiudini'-s on
electrical excitation of the motor areas of the cortex in theoranir-
outang. Since the anthropoid upe is much nearer to man than
the bonnet monkey, this study is clinically more applicable than
the obseryations which were carried out upon the Macams sini-
cus. One remarkable ditTorence between the eiTects of excitation
of the cortex of the orang-outang and that of the monkey is the
fact that very few "marches" re])roduce. It is evident, there-
fore, that the muscular movements of each individual so<niR'nt
are much more fully represented in the cortex of the oran<r-
outang tlian in that of the monkey. And, indeed, it seems to be
a general law that the higher the animal the greater is the area
of representation not only of individual segments but of individ-
ual movements belonging to one segment in the cerebral cortex.
Ik'cvor and Ilorsley have been able to show that in the bonnet
monkey the representation of the segments of the various parts
of the body is arranged along the sulcus centralis Kolandi in
liorizontal levels, and that the boundary lines of these pass across
the sulcus. 'J'he same arrangement was found to hold in the
orang-outang. The comparative relations in the bonnet and tlic
orang-outang will be clear if the accompanying figure (Fig. 6;!."))
be consulted, in which the segments are ])laced in successive
order. It will be seen that the general plan of arrangement of
the representation of the segments in the two animals corresponds
closely, the variations being due to the exaggeration of the sinu-
osities in the gyri of the orang rather than to any central aiiii-
tomical characteristics. It is to be noted that the plan of the
segments of the lower limb is truly horizontal in the orang but
antero-poiteriorly placed in the bonnet, the difference in repre-
sentation being ascribed by IVx'vor und Ilorsley to the habits of
the two animals. It is further to be noted that the representa-
OUOUIMX(i AXI) CIIAIMXC! T()(il<:THKI{ OF N'KURONKS. lOOl
tioii ill till' Itniiii of tlio uutliropoid ape and man dilTers frotn
that in tlio monkey in tliat Uie excitable area in the cortex of
the former is not continuous, being much interrupted by spaces
from which no effect could be obtained even by the application
of strong stitnuli. These unexcitable areas are situated, in the
main, between the areas of representation of the larger divisions
of the body. They are not intercalated between the intlividual
segments of the single large divisions. The higher the plane
of the animal the more pi^rfect the integration of representation.
BONNET.
ORANG.
I ONGITUDINAL FISSURE
Hifi
Knee.
Ankle.
HcUtax^ ..
• Smali
• Tots
5F
••r
STnatt
Toes. ...^ ^
AilToes
Anfcie.
Knee
Jialtuoc
5F.
Sliouider*
Mhow: I
<}>. -^-A'
Hip.
:r
^r
.•^,
•-3/i^H/Jy^r
m
IP
Pc
"^ •^
IP
Eijes.
'j^^^i^'^K^
•yes
LoiA}€T\jaw-
SYLVIAN FISSUHL
Of-
ip.
till
Fk;. C.\'>. — Ciiiiiparisim of iiiotor rcprcsfiitMtiiiii in tlic liimiict moiikf.v and in tlic
oranK-uulanj:. lAI'ti-r ('. E. lUcvcir and V. llurslcv. I'liil. Tv., Lond., lH!li>,
1). 1511, V\ii. 4. )
Subsequently to these fundamental investigations a number
of others have been undertaken to localize still more accurately
certain of the individual movements in the different areas.
Among these the study of the facial area by Beevor and Ilorsley
in 1894 may perhaps be singled out. They analyzed minutely the
facial area of the bonnet monkey with reference to the facial,
lingual, and pharyngeal movements. They undertook in this .
study especially a detailed investigation of the so called bilateral
representation. This work was very thorough, and th' results
Eur
1(102
TIIK NKI{V(H'S SYSTKM.
L
■t ' ;'
arc onihoilicd in a \(>n<f scries of tal)lcs ii.iconi])aiiyin(f tlic (tri>Miiiil
article, to wlufli tiu' reader wiio is interested can easily refer.
'I'hc report is especially valuable in cotitaininjf a tabular repre-
sentation of the series of '* inarches " observed on stimulation of
various parts in the monkey's t'ortcx.
While a priori there could have been no doubt, after the
studies upon the brain of animals, that the human brain also is
electrically excitable, the direct proof of this was first established
by observations of JJartholow* and Sciamanna.t Victor Horslev
established the fact that excitation with a feeble interrupted in-
iluced current in the facial area of the cortex of a boy ju'oduced
movements in the opposite side of the face ouly when the elec-
trodes were applied at points distant from each other and not at
interm.'diate iK)ints. Again in 18S8 Keen, of Philadelphia, J
localized in the cortex of a man under ana'sthesia the representa-
tion for the movements of the wrist, the shoulder, elbow, and
face. He extirpated the focal representation of the wrist, and
after operation the left hand was found to be paralyzed as re-
gards all movements both of the fingers and wrist. 'I'he elbow
was weak, but the shoulder and face were entirely uiuifTected.
In the same year Lloyd aiul Deaver * also stimulated the cortex
faradically and brought further evidence in favor of the view
that the integration of movement representation is much more
nuirked in man than it is in the monkey or even in the anthro-
poid ape. It was made out that considerable areas did not ap-
pear excitable at all to the strength of current employed, definite
movements corresponding to the epile})tic seizures from which
the individual had suffered being elicited on stimulation of cotn-
* lUrtlioIow. H. FApcrimPiitiil Invest ipU ions into the Functions of the
Hiiiiian Hniiii. Anu'r. Jour. Mod. Sc, f'liila., ii. s.. vol. Ixvii (1874). i)p. ;i()5-
liV.i.
f Sciamantm. K. GM avvorsari dciii' lociiiizzazioiii ciTobnili. Ardi. di
psicliiat.. etc.. Torino, vol. iii (188'2). pp. '.20!)-218.
X Kooti, \V. \V. 'i'hrco Successful Cases of Cerebral .Surgery, including
(1) the Ueniovul of a Large hUracranial l<'ibroina; (2) l*-xsectioii of Damaged
lirain Tissue: and (:?) Kxsectioii of the Cerebral Centre for the Left Hand;
with Heniarks on the (Jeneral Techni(|Ue of such Operations. Anier. .lour.
Med. Sc. Phila,. n. s.. vol. xcvi (1888), p. :i2i>: 452.
« Lloyd. J. IL. and .1. K. Deaver. A Case of Focal Epilepsy successfully
treated by Trephining and F^xcision of the Motor Centres. Auier. .lour,
Med. Sc, IMiila., n. s., vol. xcvi (1888). pp. 477-487.
(iHoriMXd ANM) ("IIAININMS TiKJKTIIKIJ oF N'KrWONKS. loo'J
fmnitivo'y restricted iiri'iis. Siiniliir ohservutiods were iiiude by
Nuncrcde* with Morris .1. Lewis.
For tiie lociiliziitioii of function in the oortox, thoroforc, cloc-
trioid excitation has hcoii of immense valne. Hnt no less fruitful
results have been obtained by the same method with re<;ard to
the localization of functioti in the bundles of fibres which pass
through the internal capsule. Here again our most important
knowledge has beei\ derived from the experimi-nts of Heevor and
llorsley.f N'aluable results by the method of excitation have
also been obtained by Burdou Sanderson J and Franck and
l'itres.»
In experiments upon the internal capsule it is essential that
the exact anatomical location of the fibres stimulated be men-
tioned, for in (litTerent horizontal planes the motor fibres occujiy
entirely dilferent positions. The term capsula interna is a bad
one, but has been so uniformly employed that it seems necessary,
at least for the present, to retain it. Hy it is indicated tlie white
fibres bounding the nucleus lentiformis on is medial side. The
term is, however, more loosely employed ami is made to include
all the descending and ascending fibres of the corona radiata,
which pass between the basal ganglia — between the nucleus
caudatus and the optic thalamus on the medial side and the
nucleus lentiformis on the lateral side. Above, the capsula
interna is directly continuous with the corona radi i, while be-
low it is directly continuous witli the base of the cerebral pe-
duncle. I'he upper and lower limits of the internal capsule
must, therefore, bi arbitrarily defined. The ujjper level would
* Nuncredo, C B. Two Siiccossful Cases of Brain Stirpory. Med. News,
I'liila., vol. liii (1888). pp. r)84-r)88.
f Bcovor, (". H., imil Victor lidrsloy. An Kxpcriineiital Invest ipit ion
into tlie Arrangement of the Kxcital)le Fitircs ot the Internal L'apsnle of tlie
Bonnet Monkey (Macacns sinitMis). IMiil. Trans. Hoy. Soc. (181(0), Lond., vol.
clxxxi (18!M) (B). pp. 4!)-88; A Beeonl of the itesnlts obtained liy Kleetrieal
Kxeitation of the So-called MotorCortex and internal Capsule in tlieOrang-
< >utang (Sinna satyrus). Phil. Trans. Roy. Soc. (189(t), vol. clxxxi (B.), Lond.
(18!n). pp. l'29-lo8.
I Sanderson..!. B. Note on the Kxeitation of the .Surface of the Cerebral
Hemispheres by Induced Currents. Proc. Hoy. Soc. Lond., vol. xxii(187;{-'74).
pp. :U)8-;5T().
* Franck, F. Le(;ons sur les fonctions niot rices du cerveau (reactions
vohuitaires et organicjues) et sur I'epilepsie cercbrale. bvo. Par. (1887),
pp. 21 -'-"3.
i
%
1004
TllH NKllVUL'S .SVSTKM.
corrospond to a pliitic rcstiiii? upon tho upper surfiiccs of the
oiiiidatc !Ui(l Iciiticiiliir nuclei; the lower level is usiiallv iletiiiod
as the re<,qoii (correspond iii<^ to tiie posterior and inferior linut of
the fibres of the ansa Icntieularis which pass tiirough the internul
capsule at its junction with tlio cerebral peduncle.
The capstda interna has been compared not inaptly to a mass
of libre bumlles arranged like the rays of a fan, the handle cor-
responding to the base o^ the cerebral peduncle, the sides of the
fan corresponding to the antero- ventral aiul postero-dorsal bor-
ders of the internal capsule, where it joins tiie corona radiata.
This appearance is well shown in a sagittal section passing
through the cerebrum (l^'ig. 03(1).
Til.
C.a.c.
X.l.
All.
Fui. (53fi. — Siifjittal scctiun tlirdURli tlic liniiii (if tlio monkey. illiistnitiiiK tlir
iiit( riiiil capsiiU". (Al'tcrC. K. Hccvor iiiid V. Horsliy. IMiil.Tr., Lmid., lSiH».
pi. xi. FIk. 15. I .1.(1., iiiitc rior or ascciiiliuf; tihrcs of tlic pais frontalis of
capsule; //, liori/.oiital fibres of tlie same : s.d., superi<ir or (leseemliiif; til'ic^
of the same: /'./.. pyramiilal liUres (excital)le) ; /'. fibres eiiteriiij; the pars
occipitalis of the capsule : .V.c. nucleus <aU(latiis; \.l.. nucleus leutiforiiii> ;
Til. tlialauuis; ('.it.c, comniissura anterior cerebri.
In horizonttd section tlio aj)pearance of the capsule Viirio^
euorinonsly at diU'ereut levels, as is shown by the accompanying
figure (Fig. G37). At the horizontal level of the capsule most
(JU()riMN(} ASM) CIIAININd T(«iKTIIKI{ oK NKl'HoNKS. loon
rr("(|iU'Mtly described (tliiil is, ii iKtri/.oiital section wliii-li atrikt's
tho vi'iitnil end of the genu corporis callosi, tiie piilviimr, mid llie
ib
A-.(
.1.11.
fiiru's
living
liiiost
H.
I''l(i. (W7. — Position of tilircsat varimis levels ol' liic ciiiisiilu iiitiTiia ol" tlic iiioiikcy.
(.M'lcrC. K. lici'voraiid V. llorsliy, I'iiil Tr., Loiul., IsiHt, pi. v, \'\k. l.i
polus occipitalis, Fij;. (ilJH), one sees tiiat it can be divided, us
Charcot suggested, into an anterior limb and a posterior limb,
which meet at an obli(pie angle to- t'orni the so-called genu
capsulii' interna'. The anterior limb is knowji as tin; [lars
frontalis capsula' interna'., while the posterior limb is designated
the pars occipitalis capsula' internst;.
The pars frontalis (sometimes km)wn as the lentifornu)-
striate portion) is snudler than the pars occipitalis and consists
at this level almost exclusively of llbres running nearly horizon-
luUy and made up in the main of axones running corticahvard
from the thalamus. As tho genu is approached the fibres assume
a more vertical direction.
The pars occipitalis can bo further subdivided into a thalamo-
lenticuliform portion (that situated between the thalamus and
the nucleus leutiforniis) and a retro-lentiforjn portion, namely,
that portion situated lateral to the thalamus, but behind the
posterior extremity of the nucleus lentiformis.
The fibres which pass through the genu capsuhe interna' are
iu»t located in the same antero-postcrior position in all horizontal
Itlanes, since the position of tlie genu alters; in the more inferior
horizontal plaiu's it is situated far more posteriorly than in planes
higher up. In the same way the pars frontalis capsuhv interna;
is shorter in inferior jilanes than in sujjerior planes, 'i'hc impor-
tance of recognizing these ditTerences in position at difTcrcnt
levels can not be too much emphasized ; much of the confusion
in pathological literature with regard to the internal capsule is due
to the fact that clinicians and pathological anatomists have j)aid
if
lo(i<;
TlIK NKItVol'S SYSTKM.
Hi
i : J I
1
ite
t'lci. <i:tH. — Iliii'i/.oiital scrtiiin llirniiKli tli<' i'ii;ht r)'ri'l>i'al ht'inisplicrr lul at
II ilistaiici' III' )(l niiii. Im'Iiiw its siiprrinr luirdcr; imtiinil si/r. lAI'Irr .1.
Dcjcrinc. Aimtoinic dcs (Viitrcs NtTVciix, raris. IMII.I, \<. lOH, KIk. ~>tl. ) .(iV,
cliiiistriiiii ; (', ciiiK'iis; ('A, liippocainiMis irnriiii aiiiiiiiiiiis> ; Ccii), kciiii
nirpiii'is calliisi ; Cc, capsiila rxtcrna ; <'<i. uyriis (IcTilatus ; ('in, pars frcmtalii
<-apMiila- inti'i-ini' ; r/i >/), k<'Iiu rapsiilii' iiilcriui- ; Cinii, linri/ontJil ImiikIIi' of
tlu- ciiiKiiliiiii ; i'iiKiii)), iKistrriiir ImiikIIc of tlir ciiiKiiliiiii ; ('ii>, pars on-ipi-
tJtlis capsiihi- iiitmia- ; Cirl, ri-troU-iitiiiilar piirtion nl' iiitmial capHiiU-; rm,
Hiilciis ciiiK'nIi : Co, rnitniiii sciiiinvalc ; coyt, niininissiini posterior ccrcliri ;
f'Kt; Kynis sulwalliisiis ; <lii, (•(irmi postcriils vnitriciili .itfralis; F,, k.vi'Uh
frontalis superior; /-'a, K.vriis frontalis iiicdiiis; /'a, K.vriiH frontalis inft-rior;
/i, snlnis frontalis superior; /i, sul<'us frontalis inferior; /'ad''. paiN trianKU-
laris K.vri frontalis infcrioris ; l-'li. fasciculus louuitniiiiinlis inferior; l-'M,
fiisciculns relrollexus Meynerti ; /•'/», fasciculus inferior or niin4ir of tlio
fornix; ^7/, nucleus halieinihe ; 'i'/'. corpus piueale ; In. insula (pars an-
terior) ; //», insula ipars posterior) ; A', tissiini calcarina ; l\\piK union of tim
lissura calcarina with the tissura parieto-occipitalis ; /,|, nyrus cinKuli ; /,i ;' i,
istluuus Kyri fornicuti ; /c lamina cornea ami tihres of the ta-nia seiuicircu-
laris ; L\i, ^'yrus lin^'ualis; hue, lamina medullaris lateralis nuclei lenti-
formis; Im'i, lamina niedidlaris uiedialis nuclei leiitiformis ; Imn, lamina
medullaris superticialis ; inl'\, facies medialis ^yri frontalis superioris; .W',
caput nuclei caiidati ; S(" , cauda nuclei caudati ; Si\ nucleus latenilis thalanu ;
yi.i.Xl.t, (fhilius pallidus < of nucleus lentiformis> ; \t.a. imtameu Hif nucleus
lentifonnisi ; O,, Oj, ^yri occipitales; nn. sulcus occipitalis anterior of Wer-
ni<'Ue; Oh', fasciculus occipito-frontalis ; ni, sulcus iuteroccipitalis ; O/*, /'a.
pai-s opercularis nyrns t'rontalis infcrioris ; O/ih', liolandic operculum ; I'nTIi,
pednnculus anterior tlialami ; po, tissura parietii-occipitalis ; I'lil. pulvinar;
ire/, cuneo-limhic fold ; n/ili). posterior parieto-limhic fold ; liTli. ndiatio
occipito-llialamica (ii-iitioleti ; N yv. ninnis posterior lissura- cerehri latenilis
Sylvii ; S(r), ramus asceiidens ; .ice, sinus corporis callosi ; >y;c, siihstantia
ftrisea centralis; .S/c, suhependymal ^niy matter; T,, sryrns temporalis
superior; 7'j. Kyrus temporalis mediiis; /,, sulcus teniponilis superior; '/'<(/(,
Uipetum ; tf<; ta-nia tccta ; Tija, anterior pillar of the fornix ; Tij I', ventriculus
lateralis; 7Vi. thalauuis ; Tp, Kyrus temporalis tninsversns ; //<. sulcus tem-
poralis tr.msversus ; 1'^, vt'iitriculus tertius ; I', stripe of Vicci d'A/.yr ; I.I,
fasciculus thalamo-mammiliaris \'ii(| d'A/.yri ; \'J', cornu antvrius vontriculi
lateralis; I'sl, cavum septi pellucidi ; Xi\ /.oiiu reticularis.
ill'
un
i t
if
(iKOl'I'lNCl AND CII.MNINO TodKTll Kit (»!•' NKrUoNKS. Kio";
I
'Mil Mule, if !iiiy,ntl('nti(iM lo tlic variiitioiH in I lie Htnicliirr of I lie
(■ti|miil(> at (lillVrt'iil liori/oiilal levels. In every eiiHe in whielMii
iiiitopsy a eirciiiiiserilted lesion of I lie iiiteriiiil eapsiile is found
(lie |iallioloj^isl, should take care lo deserilie ueeiinilcly the exiiet
loeali/ation of tlie lesion with i'e;^ai'd tu |>laneH tiikeii in the three
dinieiisioiiH of spaiH*.
(hi iht^ whole it may lu* said that the iihres iiussin;^ llirou^di
I he internal capsule correspond very well in position to the ^yri
to which or from which they ladiiitc, those fartlu'st forward lieiii;.;
connected with the frontal lohe, those in the middle with the
central iiyv'u while those more posteriorly situated run to or from
the temporal and occipital ;,'yri.
Iteovor and llorsley found that the pars frontalis capsiihi'
interna' is for the most part entirely tiiiexcituhle, or rather that
electrical excitation applied to it leads to no motor response.
The Iihres which on stimulation call forth deiinite movements
<teeiipy positions in the level most frecpmntly de.seriluMl, tiiu ^^oiiii
and the thulanio-l(>iitiform i>ortion of tli(> iiiterniil (;a|)sul(s iloit
is, the f^M'iui ami the anterior two thirds of the pars occipitalirt
cnpsiila' interna'. l'"rom hefore hu(;kward in the internal capsiih^
the arran<^enient of tins Iihres is as follows: l-'arthest forward
stimiilalion emises movements of the eyes. .\ litlj/e farther hack
tlio lihros for the openin<? of the month are situated ; then come
those ijovernin«; the movements of the head and eyes, and next
the lihri's for the ton^Mie and for the an^dc of the month, imme-
diately hehind these an* silriiited the Iihres <(overniiijf the move-
ments (d' the upper limb — lirst, tho.se for the shoulder, and next
tlwtso for the wrist, linifers, mid tliiimh respectively. After these
come the Iihres for the trunk, and last of all the Iihres troverninir
the movements of the lower limb in the followin;,' order: Hip,
ankle, knee, hallux, toes. 'I'he !irraii<;eiiu>nt in the capsnh' is
therefore :<een to he but a reproduction of that on the cortex,
which in its turn, as has been pointed out above, corresponds to
a jieripheric projection of the order of the metaineres of the;
whole body, in the accompanyinjf (lrawin<:j C'i}^- '''J!') tbe rela-
tion between the lociilization of mol(w or cfTcreiit function in the
I'ortex and that in the capsule are clearly shown. In the capsule,
as in the cortex, sc<;mental movements and not individual muscles
are represeiitetl. It is iutcrcstin<,' lo note with re^fiiid to tlio
lateral juxtaposition of the Iihres in the capsule that those most
medially situated in the thalaiuo-lentiform portion of the pars
•I '
1,.
k
1
^J
y
Ktos
'rilK NKKVors SVSTKM.
IS
■occipitiilis, wluMi stiinuliitcd, yioltlcd no motor rcsponHo, siiwu', i
\v(> liiivc scon, wlu'ii sMi(lyiii;f tlio uxoiics of tliciKU'pliiilo-tflciicc-
])liiilic scjisorv luMiroiK's, this r('<,noii of tlic ciipsulc is tliat in
N'liicli iiiiiiiy of tlicsc iixoiios arc sitii;ittMl.
'I'lic study of the i»tonml ciipsulc of I lie oranf^-ontiiii" l>v tiic
tnotlioti of cloctrioal I'xcitiition yielded, aeeonliiifir to Heevor ami
llorsley, results very similar to those obtained with the boiuict
monkey. The Idealization is ("pitoinized in the following tat)l(' :
MOVKMKNT.
From
M.
M.
IIIHX. 2
5
;{
5
4
7
4
6
5
8
5
!)
4
10
(i
S
, ,
111
10
111
»'
10
Kycs turn lo opiiosiic siilc |
l\V('li(ls cliisiii):; (l)liiil\in;,')
Hclrai'tioii of uiif^lo of uioulli to (ippositc sido
Toil;;!!!' tlaltfiuMl ami lip dirocti'd to oj>|)osil(' side . .
I'Mfxion of thuinli
Flexion of tiniicrs
I'Mcxion of wrist
I'Mcxioii of clliow
AlidiH'l ioi) of siioiiidcr
Aii<iu('tioii of slioui<l('r
Flexion of toes.
F version of anide
I'lantar extension of anUle i
The len^^th of the pars oeeipilalis of the internid eapside in
the orang-outiing, which they studied, was IS mm.
The tibrcs running from the pallium to the motor nuclei of
the cerebral nerves loiive the other motor fibres in the pons and
niediUla oblongata. These librcs throwing the nuclei of lli(>
motor cerebral nerves uiuler the inilnenccof the pallium are not,
strictly speaking, included in the term " i)yramidal fibres."
The " pyramidal tract" i)roper consists of the fibres which go
through the pyramids of the medulla and form the fasciculi cero-
bro-spinales lateralesand the fasciculi cerebro-spinales ventralesof
the spinal cord ; tlnit is to say, the fibres of the pyramidal tract,
strictly speaking, innervate maiidy the lower motor neurones by
means of which 'he movements of the upper iind lower extremity
are executed. .Many writers, however, especially English and
American neurologists, include the fibres going to the lower motor
neurones of the cerebral nerves, as well as those going to the
lower motor neurones of the spinal cord, under the term j)yram-
idal tract. This is a matter of nomenclature and of but little
significance. Th(> main point for the student to grasp is that
'4'
%
(iltoriMNd AND ('IIAININ(J TU(il<:TIIKU OK NKUUONKS. U){)\)
l)()t,li sets of lilircs lijivt> u similiir fmii'tioii t.o throw tin- Iovvcm*
iiiolor nciiroiif.s iiiidt'i- tlic iiilliit'iicf of the itiilliiiiii.
F3 oj en
<a -
a, 4, B
o 9 1^ m
o
^ 1-t r» ^
An-angoment of excitable fibres in Uio internal capaalc.
Kio. )i:t!). Di'iiwii IViiiiMi |ili(ilciKrM|ili ( iii:i};niti('<i twicciof llic iniicr.HUi
iiKPiiki'v's I Miirdiiis siiiii-ii.ii l( 11 liciiiis|ili('n'. i AI'lciC. 1%. IJccvnr iiiiil
ley, I'liil. Tr., I,<M1(I., IHilO, l>. Ml, Kin. 7.)
I'ilCI' of il
V. Mors-
Ffoni the fact that in the cortex und in tho intcriiiil (lapHule
the l)iiii(il('.s of Hl)n^s arc arranj^cd in groups (M)rr('H])on(liiig to tlie
(iilTercnt niovonicnts, and from tho fact that in tlici spina! oord
lil)r('s whii'h run for the ioiifrcst distance tciiid to he more peripli-
crally situated than thos(* wlii(!h run for shorter distanci^s, it is
not surprisiiif? to learn that in the fascicudiis eerebro-spinalis hit-
cralis of the spinal cord there is a definite firoupinj^ of the (ihres
correspond in<f to sejimiMital movements. Direct |)roof of this,
however, was adduced only recently. In 18!l7 (lad and Klatau *
*(iiui, J., niid K. I''liiliiu. Trber dio fjroborp Ijucidisulioii der fiir v»'r-
scliicdciii' I\">rpcrtli('il(' licsliiniiitcii iiiotoriscliini IJaliiieu iiii Kiicl<cmniirk.
Neurol. (Viilnilhl., L.'i|)/.. IM. xvi (1H!)T). S. 481.
wjn||taH|L
i
I
(
' i
1010
THE NKIiVOUS SYSTEM.
excited with tlie Taradic current different areas of the fresli-cut
section of the pyramidal tract of tiie s])inal cord of the dotr
Their results are well ilhi.strated in the acconqjanying dia'M'ams
(Fig. 040).
The study of secondary degenerations has yielded results sec-
ond in importance only to those afforded by the embrvological
method of Flechsig with regard to the paths followed by the
axonos of the neurones extending between the pallium and the
motor nuiilei of the cerebral and spinal nerves. The knowled'^o
afforded by the study of secondary degenerations has been derived
from two sources: (1) the study of human cases observed cliiue-
ally and ])athologically, and (2) the study of the nervous svstem
of animals in which the motor tract has been experimentallv in-
jured.
The first to investigate in man degenerations in the domain
of the pyramidal tract was Tiirck in 18,51,* who in cases of long-
standing hemiplegia observed degeneration not only in the spinal
cord but also in the posterior and superior part of the internal
capsule and in the middle of the base of the cerebral peduncle.
The illustrations accompanying his publications are very crude,
but nothing but praise can be said of the accuracy of his obser-
vations. Tiirck stated that when definite parts of the cerebrum
were destroyed in any way, as a result there became diseas(!d in
every instance definite bands of fibres which are situated in the
internal capsule, the base of the cerebral peduncle, the ventral
part of the pons, the medulla oblongata, and the spinal cord.
This " secondary disease," which he observed in a large series of
cases, manifested itself in the appearance first of numerous fatty
particles and later by atrophy. Tiirck observed that this second-
ary disease occurred not only wlien the lesion was situated in the
cerebrum, but also whenever the bands of fibres in their course
between the cerebrum and the spinal cord, or even in the spinal
cord itself, became interrupted, lie made out by the study of
these secondary degenerations the decussation of the pyramidal
tract in the medulla oblongata, and it is to him also that we owe
the recognition for the first time of the existence of a direct
pyramidal tract (although not recognized by Tiirck as such)
* Tiirck, li. UcIkt sekundilre Erkriuikung einzeluor Rllckpiiinarks-
striiiif^e uiid ihrer Fortsctzuii^^cii zuiii (ieliirno. ZLsclir. d. k.-k. Gcsi'llsch.
(1. Acrzto zu Wieii (\i<'i2), ii, 511 ; (1853). ii, 28!).
G110U1MN(} AND CHAINING T()(JKTIlKIi OP NEUHONKS. l(»ll
Honwlntvriil tntiik inusclcs.
T(n',i iif /ms-
ti'iior <'.<■-
trintiti<s
{liiimoUtt-
trith.
Hi ml li'tj
ikdiiiiiliit-
f /■(//).
Seywcntdl tntiik miinclr/HlioiiKildtcriil).
Trunk {hoinoUiterul).
1 1 ill d leg
iiiid tdi'a
{liiiiniiliit-
(•/■<(().
Flunk +
tniiik
Uii'iiiulat-
eritl).
Si'llinfutdl
iniiik
i(ii(.s(7('.s
(hoiiiiiliit-
(Id/).
Trunk + Jhmk {Iwnioldtirdl).
Extension at knee.
Fle.iion at knee.
Fle.i'i(iii in hi}i joint.
Trunk + flank {homo-
lateral).
Flank {homolateral).
Trunk iiinsf/cs (homolateral).
a.0
' a
r>
E
Fle.iiiin ill
hi ji joint
i homolat-
eral).
t'le.rion in
hil>. knee,
and ankle
{homolat-
eral).
I
l''i(i. (MO. — Kxpi'vinu'iitiil stiiniilation of fivslily cut suhsluiitiii iill)!i (if <liif;'s spinal
ciird. ( After .1. <ia<l uiiil K. Fliitaii, Neurol. Centrallil.. Leip/.. M. xvi, lHit7,
S. 4S3-48r), Imks. 1-.-). ) \. Level ofTIX. I?. Level of T VI I. ( '. Level of
TX. 1>. LevelofrX. K. Level of (' VIIL Stimulation at />' aniU,', uiove-
iiieiit.sof trunk I liojuolateral 1 ; at ;», tliitjli ' skin of aliilouieu : at «, lioniolat-
eral sef^niental trunk nuiscles + extension of lioinolatenil foreleg i plantar
Itexion and ailduction of toes); at k. no muscular eontraction.
mj-'X^atPSitKC i
1012
TIIK NKUVOUS SYSTKM.
■)i
whioh passes down in the ventral column of the cord on the same
side without decussation.* lie asserted that these tracts degen-
erated oidy in a descending direction from the side of the lesimi
altiu)ugh he recognized that above a given lesion there were numv
fibres which degenerated in an ascending direction. 'J'iirck sug-
gested that the cause of the secondary degeneration was probablv
the interrujjtion of conduction, and inclined to the view that the
coTuluction direction could be concluded from the direction as-
sumed by tlie degeneration in a given case.
This preliminary knowledge of secondary degenerations was
much expanded by the investigations of Houchard,! Charcot,*
Pierret,* Xotluiagel,|| von Monakow, and others. It has l)eeti
possible in a large number of human cases to follow the second-
ary degeneration not only of the whole pyramidal tract, but also
of the separate portions of this tract, to their destination. A
good example of the secondary degeneration of the pyramidal
tract after a cerebral lueniorrhage in the region of the internal
capsule is illustrated in the accomj)anying sections (Figs. 041).
I''rom what has been said of localization, it is obvious that lesions
of the cerebral cortex will be likely to cause only partial sec-
ondary degeneration of the pyramidal tract, since, in order to
lead to complete degeneration of the tract, an enormous area of
cortex would have to be involved, and, as a matter of fact,
hu'morrhages and other lesions implicating the cortex of tiic
pallium and centrum ovale are not sufficiently large to lead to
destruction of the cell bodies or axones of all the neurones ex-
tending between the pallium and the groups of lower motor
neurones. Tiifortunately for human beings, however, the nu)st
frequent place in which the pyramidal tract suffers injury is the
internal ca])sule. Here the fibres are closely ])ressed together
* Tlirck designated this the Iluhen- Vorderstranghnhn.
+ noiR'lianl. ('. Dos (lop'iu'Tatioiis sccondiiires dc la moelle ('piniore.
Arch, gi'ii. do iiicd.. Par. (1866^. i. pp. 272: 441 ; r)(it : 578; ii. 27.'?.
X Clmrcot, .1. M. Lemons sur Ics iiialadios du systi'me iioi'vciix fiiitos h 1m
SalpotriiMv. 8v(.. I'aris (1872-"7;}).
* I'it'iTcl. Coiisiduratioiis anatomiciiies ot patiiologiques sur Ic faisecaii
postorioiir do la moollo opiniorc. Aroli. do physiol. iionn. et imth., Par., t, v
(187;]). pp. r):i4-.')4r..
II Notluiagel. H. ExporimoTitolle Uiitorsucluiiigon uobcr die Ftiiictioiicii
dos Gehirn.s. Arch. f. path. Anat.. etc., Perl., 15d. Ivii (187:3), pp. 184-314;
Hd. l.x (1874). S. 12!»-14!).
i *
I
L
Fl(i. (ill. — DcKi'iit'iMliiPii. fiillowiii}; lin'iiiDrrliiitjc of six iiioiith--' d
iiuclciis latt'iMlis tlialanii anil in the l('iiticiii(>-ii|ili<' |iiirliiiii iil' ||
iii'utidii, ill tli(
If CilpSlllil
interna. i .M'lrr ('. voii Mmiakow, ( JcliiriipallioldKit', Wicii, ls!i7, |'j.r
171-17.').) A. (»lili(|nc liiiiizonlal section tiiroUKli the aiitei-iiir part of iTk
imeleiis li.v|iotlialaiiiiens. corpus liiiysi ; //, eyslic nodule iillcd will
transt'ornied lil 1 ; //i, /■', pericystic sol'teiiiii;;
<■/, caiisiila interna ; />,
secondary defeneration in the capsiila interna, dotted red ; llw |iyramida.
tract is interrupted ami totally dejjenerated ; ,/. insula; /,''.' niicleii.s
iiy))ollialainicus : /'((/, iieduncnlns cerehri ; //, traetus opticus; /,(, nucleus
leiitllorniis
corpus striatum ; Inl, nucleus lateralis tlialai
111 ; iriil.
nucleus ventralis thalaini ; hue, lamina mediillaris. H, (', I), t'roiilo-liori-
zonlal sections i plane of Meyiiert i throiinh the hrain stem of the same
ISC ; |{, level of the coUicillus sil]ierior and of the pedunculiis cerehri ; ('
liddle of pons ; 1). medulla ohloii<;at;i
T
A(lh
iilicdiictus cereh
le (IcL'eiu
a. I
///. uervils
rated pyramidal tract
iiotoriiis ; /// A'.
nervi ociilo-motorii ; si'h. lemniscus medialis ; ///,, fasciculus loUKit
medialis ; ISA, hracliium conjunctivum ; i!r.\,
nucleus
iidinalis
>rachium poiitis; /•(•(/, pcdun-
(T, corpus
cuius cerehri ; iii/r, pyramidal tract def;enerateil on the rifjht sid
restitorme ; I'. (/»/'v/. ti-aetiis spinalis uervi trinemini. K. Dcjieneratcd til
in the spinal cord of the same case ; 1 :i, pars cervicalis ; t -S, pars tlioracalis •
!t- 13, jiai-s lumho-sacralis ; /»//)■, fascirulus cerehro-spinalis venlralis; jti/ni]
fa.sciciiliis cerehro-spiiiiilis lateralis.
OROUIMNa AND CIIATNINO TOOETHKR OK NEURONKS. l()i;}
£ H
V!l>'a
l>!ir
vyr
^^••-■^pSI
vyr
pur
PVa
i>y>;,
pyr
VUl-a
py
pyra
ptir
left. I right,
pyr
[014
TIIK NKUVOl'S SYSTKM.
h'}
i
into a compact bundle, and a tol('ral)ly cin'tunpfribod lesion will
suttico to lead to complete interruption of all tlu! descendini'
motor axones. 'I'iiis rej^ion of tlie internal capsule is supplied
in the main by tlio HO-callud lenticiulo-striate artery of Duret, and
in by far the greater proportioji of cases of Ineinorrliagp this
artery is involved. So fre(piently does liaMnorrhage take place
at this site that this artery has been designated by Charcot as
the "artery of cerebral lia-morrhage." This explains why it is
that in the nnijority of instances of cerebral haunorrhage there
results total hemiplegia of the opposite side of the body. At
autopsy the motor tract below the lesion will be found degener-
ated, aiul the area of degeneration can be distinctly nuide out in
the cerebral peduncle, in the pons, in the medulla, and in the
spinal cord as far as the lowest level to which the fasciculi core-
bro-spinales penetrate. If an autopsy be made before too long
a period has elapsed, the area correspomling to the ])osition (<f
the motor fibres shows a diminished consistence, and on cross
section the area may look somewhat darker and rather more
gelatinous than normal. If bits of the tissue be placed in Mid-
ler's fluid for a few days the degenerated area presents on cross
section a typical appearance. One makes out a clear, shar|)lv
circumscribed zone, distinctly visible to the naked eye. If sec-
tions be examined shortly after the lesion has occurred, numerous
cells containing fat droplets, the so-called granular corpuscles,
will be found present in the degenerated area. Specimens
stained by Marchi's method show the degenerated fibres stained
a deep black color. If the individual have lived for a long time
(more than three months) after the legion has occurred, Marchi
preparations may not show the degenerated area well, owing to
the absorption of the myelin of the degenerated tlbres, but Wei-
gert's method will, at this stage, britig out clearly the area of
degenerated fibres. Instead of a mass of normal, black-stained,
medullated nerve fibres, a yellowish })atch, in which only a few
normal nerve fibres are retained, can be made out. It is impor-
tant to emphasize, however, the fact that in such degenerated
areas a certain number of fibres nearly always escape degen-
eration. This is owing to the fact that in the area ordinarily
designated in the spinal cord, for example, as the fasciculus ceer-
bro-spinalis lateralis or lateral pyramidal tra((t, there are, in addi-
tion to the medullated axones of this tract proper, a number of
other axones which do not belong to it. Probably no absolutely
..L..
i (!
(i|{()riMN(! AND CIIAININM} T()(JKTIIKIl OF NKUIIONRH.
1(115
pure tnu't exists in tlic spinal cord, Imt there is everywhere! a
{^renter or less adiiiixtiire of liitres of dilTereiit tnicts. This ac-
counts, therefore, for the preservation of certain normal mediil-
luted tihres in tlio area of the pyramidal tract even after all tho
motor fibres dewceiidin<j from tlie pallium iiave nnderf^one second-
ary dej^'cneration. Anotiier reason, however, for the j)ersistenco
of healthy niednllated fibres in the rej^ion of one lateral pyram-
idal tract after unilateral cerebral lesion is the presence in each
6 —
l'"l(i. tM:2. — A. I'ortioii lit' |i.vi'aiiii<lal in Inict in cross scclinii whicli Iims inulci'Kiine
sccdiidary (icKt'iiti'iition ; o, axoncs; /), Ki"iiniiliir and finely tilnons area of
tninsfoi'incd ncnro;;lia ; c, sinKJr normal nerve tilires renniinin^ nniiijnred ;
r, cavities wliicli liave arisen liy the Wreakin;; down and absorption of nerve
tilires. I!. Section of the normal pyi-amidal trad ; ii, coiineclive-lissne s<'pta ;
//, healthy nerve (ihres. (After ( '. von Monakow, (}ehirn|(atliolonie, Wien,
lS!t7, S. 7^'4, l-'if,'. 1"<). )
liitenil pyramidiil tract of mediillated axoncs from both cerebnil
hemispheres. As we sliall see farther on, it has l)een proved that
besides the crossed axones in the lateral pyramidal tract there
are always a certain number of axones which descend in the
liiteral bundle uncrossed from the cerebral hemisphere of the
same side. The differences in appetirance of the healthy py-
ramidal tract and of that which has undergone secondary de-
generation are represented in Fig. 04"^.
J '■
(•IIAI''I'KI{ l,\I[.
INTKIlMI'.KIAIfY AND ll'l'lllf .M<»I'(>K N i;i HON I'.S (roNTI N I i:ii).
Kilii'cs frum llic |ialliiiMi lo (lie iiiolur nuclei uf tin rdiriil nerves Stmlii^t
of lloclie unci iilliers -Itesnils (if exi ir|iiil ion iif icieuli/eil nrrn-i of t|i(.
eorlox — Si;,'nincani'e of uncrossed fibres of tlu> pynimidai trael — Inler-
cuiiition of ilemlriixones lielween upper motor neurones iinil lower tnolor
neurones — '{'he centrifutriil corlico-inuscular conduction path — Clinical
symptoms foilowiu),' lesions of dilTercnt portions of the path.
2. Those the Axones of which run to the Motor Nuclei of the Cerebral Nerves.
'rill'; sillily of the (Icjjt'iH'fiiUMl (losct'iiiliiifj; motor iixoiics in
luiiiiiiii hciiiLTs by niciitis of the incthod of Miifclii lius in rocciil
years thrown a llootl of new liijlit upon llic (listril)iition uf tlicsc
nxotios. As :i siii<f|o instiiiicc of tlio iippliciiltility of tliis inclliod
and of tilt' special advanttigos iilTonlcd hy it, may bo mi'inioiicd
tlio rcct'iit rcscarcli of lloclit'* in connection with two fatal ca.scs
oceiirrinj; clo.se toj,fetlier in which there was soflenini; of oiic
cerobral heinisphere. His lindin<i;s are very remarkable in nianv
ways, and it is as yet too early to pa.s8 jiidfjment upon tl'cni.
^fore eases iniist be studied by the same method before the last
word can be said. It had been <;enerally belie. ed that in tlu
ot'rebral peduncle ihe fibres eomin<^ from the pallium to the motor
nuclei of the cerebral nerves were most medially i)laeed, while
those for the arm and leg were more laterally placed ; and there
is much eliiiieo-iiathological evidence in favor of this assump-
tion, lloehe's ea.«es, however, did not support the prevailing view.
The area in the section of the jies, corresponding to that ordi-
narily taken to be the one in which the fibres innervating the
motor nuclei of the cerebral nerves are situated, was in lloche's
case entirely free from degeneration, although clinically tlie
* Iloclic. A. l?oitriifj;c zur Anatomic der Pyriunideidialin und der nhi'icii
Sclileil'e ncbst, Hcmcrkunfjcn ueher die altnormen Uiindel in Tons und )li'-
dulla oblongata. Arch. f. Psytihiat. u. Nervenkr.. Ucrl.. I5d. xxx (ISIIS). 11.
i. S. 1():$.
lOiC)
(lUoriMNd AND ClIAININCi 'nxiKTIIKIt (il' MU'UONK'
lol
piirulysis litid iiivnlvcil the ildiiiiiiii of llic ('iM'cl)ral iicrvrs. <Mi
tlio otlicr liiii'il, ill lliK'lic's ctisu liiti'i'til from tlio un>ti iisiiully
(li'sijfiialcil as I lie iiiolur iin'u, in u Hi'ctioii of tho ccrtfbrul |m-(1iiii('Io
wliii'li lias always Itt cm l»clifV(Ml to he an area tlirixij^'li wliirli scn-
sory tilirt's pass ii|i\var(l iiilo tlic ('('icldMiin, tl»';,'<'n('rali(»n liiid
(UHMirrcii in a «'»'iitril'ii;,'al direction. Iloclic I'oIIowimI the df^xcn-
onition from the hiisn of the ccrfbrul peduncle and downwurd.
'riiu pyramidal irart proper (for llie upper iiiul lower extremities)
eorrespoiidetl closely to I lit! descriptions usually ;,Mven of it.
'I'liiiH no libres were ;,'iveii oil' from it to the nuclei of the iiervi
oenlo-motorii, althoii^'h a jfreiit niimlier were followed from it to
tlni nnch'iis nervi fa<'ialis iind to tlio nneleuw nervi liypoj^lossi.
Ilttehe found lilires ;,'<tini,' from the pyramidal tract of one side
to the nucleus nervi facialis of the same side, and also ueross flie
raphe to Ihc! nucleii.s nervi facialis of the opposite sid(!. A larj^e
number of librea {^oin^j from thu pyramidal tract to the nucleus
nervi hypoj^lossi of the huiik! side and a few to ihc nucleus nervi
hypo<,dossi of the opposite side could also b(! made out. In the
spinal cord dej^enerated libres could be traced from both pyram-
idal tra(!t.s into the }?ray matter of the ventral horns; and it is
worthy of note that from the lateral pyramidal tract libres ^o
not only to the ventral h'>rn of the same siih;, but some of them
pass throu<(h tlu! ventral white commissure to enter the ventral
horn of the opposite «ide.
Iloche also as.serts that the fibres from the ventral jiyramidal
tract (fasciculus cerebro-spinalis ventralis) run in \o terminate in
the gray matter of the ventral horns of l)oth sides, but mainly in
the ventral born of the opposite side of the cord, llociie's find-
ing, that libres of upper motor neurones run to the cerebral
motor nuclei of both sides, brings these nuclei closely into accord
with the motor nuclei of the spinal cord.
Si ill more interesting, however, than thes(! double relations of
the pyramidal tract to the cerebral motor nuclei are the observa-
tions of Ilotdie with regard to another descending motor tract.
In his first case, especially, he was able to jirove that the nucleus
nervi facialis and the nucleus nervi hypoglossi receive mediillated
axones from tlie cerebrum by a path entirely separate from the
jiyramidal tract, which descends through what we have been
accustomed to consider as an almost purely sensory region —
namely, that of the medial lemiusous. Coming out of the lem-
niscus niedialis in the pons and extending between it and the
I
■ 4
1
h
HllS
TllK NKIIVOUS SYSTEM.
. t 111 'I:
m
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(il{OUPIX<; .VND niAININO TOOKTIIKR OK NFA'UOXPX joH)
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1020
TIIK NERVOUS SYSTEM.
nucleus nervi facialis of the same and of the opposite side could
be made out a number of degenerated fibres. In the same way
coming out from the stratum interolivare lemnisci of one side
could be seen a number of degenerated fibres extending from it
to the nucleus nervi hypoglossi of the same side and throufrh the
raphe of the nucleus nervi hy])oglossi of the op])osite side ( Fig. 043).
That these fibres are entirely distinct from the majority of tht;
fibres of the lemniscus medialis is })roved not oidy by Lhe fact thai
they degenerate in a descending direction, but also by the fact
that higher up in the nervous system they are entirely separated
from the rest of the fibres of the lemniscus medialis. I'hus in
the upi)ermost planes of the cerebral peduncle these fibres do
not lie in the region of the lemniscus at all ; they are situated in
the base of the peduncle in the immediate neighborhood of the
fibres of the pyramidal tract, but are placed lateral to them.
These fibres in reality appear to come out of the internal capsule,
whence they go into the base of the cerebral {)eduucle, occupying
a position just lateral to the fibres of the pyramidal tract. In
the pons, however, they become somewhat sejiarated from the
fibres of the pyramidal tract and become displaced into tli(>
region of the lemniscus medialis, running downward in tiiis
bundle for a considerable distance. It is interesting to note tliat
this descending centrifugal bundle of the medial lemniscus had
been made out many times before, though its significance had
not been properly valued. Thus it had long been known from
the researches of Flechsig and von liechterew that a certain
number of the fibres from the medial lemniscus become nuidul-
lated at a much later period than do the majority of its fibres.
Von Bechterew had even given this bundle a special name.*
lloche has studied the position of the fibres in the brain of
the newborn bal)e, when they are easily distinguishable owing to
the fact that they are non-niedullated and appear as pale areas
(Fig. (M4).
It is especially interesting that in Hoche's two cases the
most medial parts of the base of the cerebral peduncle (Flech-
sig's frontal cerebro-corticopontal path) were entirely free from
* von Ik'ciiterew designaliHl it the accessorische Schleife. Si^hli^siii^'cr
calls it the latentlc jiontixe lii'ivdel. It is not, howi'vor, idontical willi llii'
temporal coroiiro-corticoiHintal ]iath of Flcclisig; for in the liaso of llic
peduncle Iloclie's fii)ivs lie lictweon the temporal cerehro-corticopoiital piilli
of Flechsig and the til)res (jf the pyramidal tract.
HSSH?^*^
(HiOL'PING AM) CIIAININO TOGKTIIER OF NEURONES. 1()21
(.k'gt'iiL'ratioii ; aiul lliat also tlio most latonil portions of the base
of the peduncle (Flechsig's temporal cerebro-oorticopontal path,
Biindel von der Schleifc Ins zum Fuss) were also entirely free
from secondary degeneration.
r '
Fiti. tut. — Non-nu'dulliitcd (ilircs in llic Ifiimisciis at l)irtli coiTcsixiiKliiif; to tlui
cciitririiKal IiuikIIcs oI' tlic Iriiiiiiscus. i.M'tcvA. n(i('l\f, Anli. I', rsydiiiit.,
Hcrl.. |{<1. XXX. ISitS, Till', iv, Fius. ;.'l to :iH. i A. Level u\' tlie colliculiis in-
ferior. H. Level of superior part of pons. ('. Level of iierviis tri^ieiiiiiiiis.
I). Level (tf .spinal extremity of nucleus nervi faeialis. H. Level of nervus
vajius.
In the most medial part of the podunclo, Fleclisig atul otlicrs
have located the path from the pallium to the nuflei of the tuotor
cerebral nerves, while by Spitzka it was ))laced in the lateral part
of the pes, in the so-called bundle from the leniniscns to the pes.
\|
1-^ ;.
1022
TIIH NERVOUS SYSTEM.
J' ^
It soems probable, therefore, on comparing iloclie's researclies witli
those of other investigators, tliat tiie nuclei of tlie motor cerebral
nerves can be thrown under the iiitiuence of the pallium bv jueuiis
of fibres which run in two entirely ditferent paths — (]) apatii situ-
ated in the pes medial to the pyramidal tract, and (2) a path in tlnj
])es lateral from the pyramidal tract. That d liferent motor paths
destined for the cerebral motor nuclei nun nossibly exist is of tlm
highest interest in connection with the pu/,/. ling clinical j)rol)l(!ins
met with in the domain of distribution of the cerebral motor
nerves. We may hope that further investigations with the Marclii
method of secondary degeneration after cerebral lesions will clear
up aiuitomically these clinical differences, especially with regard
to paralyses of the face and tongue which have so long puzzled us.
In one of Iloche's cases there was degeneration of an abnoi-
mally placed bundle of fibres of the pyramidal tract, which evi-
dently corresponds to the abnormal bundle described by Pick,*
Heard, f of Pittsburg, and others. It would seem that in a few
instances a bundle leaves the pyramidal tract of one side, under-
goes premature decussation in the raphe, and takes an abnormal
course through the medulla oblongata, fusing finally again with
the fasciculus cerebro-spinalis lateralis below the level of the gen-
eral pyramidal decussation.
One of the most fruitful of all the modes of investigation for
the determination of the course of the fibres of the pyrauiiilal
tract, especially of individual portions of this tract, is that of ex-
tirpation of the whole, or, more particularly, of limited areas of the
motor cortex, with subsequent study of the nervous system for
secondary degenerations. The earlier studies of von Guddeu,];
von Monakow,* Franck and Pitres,|| and Moeli ^ were carried
I
* Pick, A. Ueber ein abnorines Fuserbiiudol in der Mcnschlioht'ii Me-
diillfi ohioiiffiita. Arcli. f. I'syohijil. u. Nervenkraiikh.. IM. xxi (l.,"!:i!)).
f Ilciird, .1. I). Ueber !il)n(>rme Nervetibiiiidel in der Medulla otjloiignl.i
des Meiisclieu. Arl). a. d. Inst. f. Anat. u. Physiol, d. ('mitral iiervensyst. an
(1. Wicn. Univ., Leipz., u. Wien (1894), II. ii, S. H<5-!)().
X von Gudden. Cor.-Bl. f. seliweiz. Acr/te (1H72), No. 4.
* Experiinentelle Heitriif^e zur Keniitniss der Pyramiden- uiid Schleil'cn-
bahn. Cor.-Bl. f. .schweiz. Aerzto, Basel, IM. xvi (1884), S. I'J!» ; ir,7.
I Fraiit'k, Francois, el A. Pitr(>s. Des ilejifeiienitions seeondaires dc In
nioelle epiniere conseeutivc^ a I'ablation du gyrus signioide cliez le I'liien.
Gaz. nied. de Par., 0. s., t. ii (1880), pp. 153-154.
^ Moeli, ('. Uel)er sekundilre Degeneration. ArcIi. f. Psyclnat. n.
Nervenkr., lid. xiv (1883), S. 173.
GROUPING AND CHAINING TfKJETIIKH OF NEUKONKS. 1023
out witli the aid either of the carmine method or the method of
Woigert, but the newer studies liave been much more exact owing
to tlie possibility of greater accuracy afforded by the delicate
method of Marchi. With tliis method Marchi and Algeri,* Mura-
toff,f Mellus,J Langleyand Sherrington,'* and Sherrington|| have
obtained important results.
Of these experiments, those which have been carried out upon
monkeys are of course most valuable, since they yield conclusions
more applicable to man. In general it may be said that they
have shown that the course outlined for the fibres of the pyram-
idal tract by the embryological method and by the method of
electrical excitation is correct. The experiments have also cleared
up the puzzling findings in human cases, in which after unilateral
cerebral lesion degenerations in both lateral pyramidal tracts of
the spinal cord were observed, since they prove conclusively that,
after extirpation even of minute areas of the cerebral cortex in
the motor region, fibres of the pyramidal tract degenerate, not
only in the lateral pyramidal tract of the opposite side of the
spinal cord, but also in the lateral pyramidal tract of the same
side of the cord. P^ach cerebral hemisphere in the monkey is
connected with the ventral horns of both sides of the spinal cord.
The explanation of the appearance of degenerated fibres in
both lateral pyramidal tracts has been attempted by Sherrington
and by Melius. Sherrington's earlier researches led him to be-
lieve that there was a total crossing of the fibres of the pyramidal
* Mart'lii, V., e <!. Algeri. SiiUe degcncriizioiii discpixlcnti consecutive
a Icsidiii speriincnlali in diverse zone dellacorlecciacercbrale. Hiv. sper. d.
freniat., Roggio-Kinilia, vol. xii (18H6-'87). pp. 2(»8-2r)2.
f MiiratolT, W. Secundiire Dcgcnorationcn nacli ZtM'stiiruiig dcr niotor-
ischen Spliiire dcs Gohirns in Verliindiing init dcr Fragc von dor Localisa-
tion dcr ilirnfiinctioncn. Arch. f. Anat. n. Pliysiol., Anat. Abth., Leipz.
(189:5), S. !»7- 110.
\ Mellns, K. L. Preliminary Note on nilatoral Degeneration in the Spi-
nal Cord of iMonkeys (Macacus sinicus) following Unilateral Lesion of the
Cortex Cerebri. Proc. Hoy. Soc, Lond. (1804). May 2;}.— Kxperimental De-
generations following Unilateral Lesions of the Cortex Cerebri in tlu! Bon-
net Monkey (Macacus sinicus). [Abstr.] Proc. Roy. Soc., Lond., vol. Iviii
(18!»r)), pp. 2()(i-214.
* Ijangley, ■!. N., and C. S. Sherrington. Secondary Degeneration of
Nerve Tracts following Removal of the Cortex of the Cerebrum in the Dog.
.1. of Physiol., Lond., vol. v (1884-'8r)), pp. 4ii-C,ry.
II Sherrington, C. S. Note on Kxperimental Degeneration of the Pyram-
idal Tract. Lancet, Lond., i (1894), p. 265.
67
IdiH
THK N'KKVorS SVSTKM.
tract. Mi'lliis concluded tliat, instead of a total crossinj:;, ('crtiiiu
of the lllu'es of the pyramidal tract did not cross at all — a con-
clusion with which .Sherrington in iiis more recent articles ap-
pears to agree.
The cxperinu'iits of Melius, wliicli wore carried out under the
direction of Victor llorsley in London, and wiiieli are still beiuir
continued in l)r. Mall's laiH)ratory in Baltimore, may be referi'ed to
somewhat more in detail. Melius operated upon the bonnet monkey
extirpating small areas from the motor cortex, soinetinu>s fr<jm the
hallux centi'e. sometimes from the thund) centre, sometimes from the
various centres in tlu^ facial area. The aninuils were killed in from
two to five weeks after the ojM'ration, and the brains studied by the
method of March i (Ki<r. t'>4.*)).
L
Fui. ri<l5. — Rraiii "f iii(iiik(>y i ^flll•llnl.^< Khiinis], sliowiiii; (•(irticMl area cxlii'iiatcd.
//, lialliix ; 7'. tlimnli; /■', I'acial. Hcinj; IIk' upper hnnlcr nl' lacial an iiupim
the aiUt ri(ir iintral k.v1''ii^. tlic iiKivciiiciil represented lieiiiK eliisme (if llie
«il)p(isile eye and nlractiiin iif tlie opposite eoriier of tlu' inoiUh. ( Kxperi-
nienls of i:. L. Midliis. )
After lesions of the hallux centre, there detronerated many asso-
ciation libres. both coarse and fine, wliich ))ass from the central
<:yri down as far as the levid of the inferior •i'enu of the sulcus cen-
tralis Kolandi. Some fine association libres were found to pass to
the lobulus jnirietalis sui)erior. others to the ])osterior ))art of the
gyrus frontalis su])erior, and both co.arse and fine association fibres
were found to connect the hallux centre with tiie lobulus parii-
eentralis. This centre was further connected, by means of fibres
which ])asse(l throu<j:h the corpus callosum, with the h(>mispliere of
the opjjosite side lieinjj: distributed in the opposite hemisphere in an
area on tlie whole similar to that wh(Mic(^ they arose.
The projection fibres which defj^enerate after lesion of the hallux
centre could be followed through the medial iialf of tlie centrinn
it
OUOL riN(i AND ClIAININd TOUKTIIKR OF NEL'KONES. 1(J25
" 'rt it
Cap'it nuclii vdutlitfi..
Pars fruntiiU.s capsuUr
iiiUrmv.
I'eiitrwuliin Ititinilis.'
larnu mtjitrius.
I'nidinen.-
I.Vllll lllllSllIll illtlllKV.
Illiibiis ixillutiiK.
Iit'ijenvratvil itrva
(li(iHii.i).
ruin incii>il(iliii ciiiisn-
Iw inti'niir.
Thttldiiiits..
.{(tuetlnclus ct-rebri.-
I'nlriiKir..
llil<i><ir(iiii)>\iii..
i'v lit I kill us littirulis..
I'lci. ()l!i. — Iluri/diitiil sci-tiiiii 111' iiKPiikfy's luaiii sliiiwiii;: aria of (li'ficiicratiuii
ill iiilcnial capsule. fnlluwiiiK N'siuii uC hallux ctiitri'. ( Kxporimt'iil and
Iii<|)aralioii liy K. L. Milhis. i
Kl(i. (147. — Di'fjini rated area in V\n. Mi>. eularjieil. i Kxperiiueiit ami iilinto-
iiiicronraiili liy K. L. Melius. '
1()L'(!
TIIK NHIiVors SYSTEM.
*' I
s<mii()val« to the iiitenml capsule, in the lower levels of which they
are located in the middle thii'd of tlu' pai's occipitalis oi- itosteriof
Mini) (Fi}^s. CM and M7). Here a ;jreat many line degeueratiil
fibre.'! pass out of the internal capsule into the thalamus. The iial
lux fibres in the basis pedunculi are somewhat evenly scattered over
the middhi third, and it is especially important that a ntnnber of
coai-se degenerated fibres pass into the substantia nij^ra appaivnt I v
to terminate there.
At the level of the decus.satio i)yramiduni (Fiof. <i4S) the hallux
fibres underffo partial decussation, the majority |)assin<^' over into
Fl(}. 648. — Det'Ussiitio pyriiniiduni, liiiUiix Icsioti, sliowiii^ dct^i'iH'i-ati'il liliic^
passiii}; to fiiscicillus (•t'n>))ri>-s!)iiiiilis hitcralis of liotli sides. ' F.xpfiiriiciil
iiiid plioto-niicroKnipli l)y 10. 1.. Melius. )
the fasciculus cerebro-spinalis lateralis of the opposite side of tin'
cord, a smaller portion going" to the fasciculus cerebro-spiuiilis i;it
(i|{()riMN(i AND ('HAIM\(} T()(}KTIIKIt OF NKl'KoNKS.
1027
(Talis of tlic sjitiic side. The relative iiuinlior of crossed and uii-
erossed libres varies «'onsideral>ly in the dillereiit aiiiinals experi-
mented iiiM)ii. A few libres pass down in the faseicuhis ventralis
Km;. tilO. — Spinal cipi-d iit tlic level cpI' clevetilli tlionicic rout, liallux lesion. Bi-
liileral (leKenenitioii. ( Kxpeiiuieiit ami |ilioto-iiiicro};ia|)li l).v K. L. Melius.)
of tlie eord of the same side, wliich jjroves tliut in the iiionkey, eoii-
trary to tlio general statement, there is a very feebly developed fiis-
eienlus eerehro-sj)inaIis ventralis (Ki"-. (il!(). The deo'enerated libres
conld he followed down throiif^'h tlw cervical and tlioi-acic coi'd
without showino- diminution in number, but in the luinl)ar rejrion
of the cord the degeneration in the lat«,'ral tnicts of both sides aiul
in the ventral tract on the same side Ijcgins to disappear, although
certain lii)res extend below the level even <)f the third sacral root.
Foll«)wing extirj)ation of tjie thumb centre (coi'tex of posterior
central gyrus between inferior extremity of sulcus inter])arielalis
and sulcus centralis RoJandi, a little above the interior genu of
the latter sulcus in the bonnet monkey) association fibres degen-
erate to the anterior and |)osterior centi'al gyri. the ])osterior j)or-
tion of the gyrus frontalis medius and the gyrus fi-oiitalis infei-ior
and to other gyri of the cortex. A cei'tain nimibci- of ass(«'iation
tibres from the thmnb centre pass through about the middle third
of th<' corpus callosum to the heniis))liere of the o])|)osite side.
Fine and coai-se projection fil)res degenerate from the thumb
centre downward through the centrum semiovule. The line tibres
, i
I i
I I
\ "
I 'J
lO'JS
TIIK XK 11 vol's SYSTKM.
t(>niiiiiiit(> ill tlio tlialiumis, tli«> liiry:*' liluvs (pynimidal tnicl libros)
occupy ill (lie iouci- lidrizontal levels of the iiitcnial cansiijc tlic
middle third of the pars occipitalis or posterior limi». In the husc
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Fl(i. ().")(),— Sect ii 111 "f :>piii!il (111(1 at the level (if first cervical nnit ; (leKciicralinti
ill lijjiil I'asciciihis ceiclii-o-spinalis lateralis after excisidii of tliiinili centre of
left liciiiis|(licre. ( I'.xpcriiiienl and |ili(it(p-niicr(ij;ra|ili by I',. L. Mellns, )
1
of the cerebral peduncle tlie tlmiiih liitres occupy the iiiiildle thii'd
of the area as seen on cross section. A larye ntiiuber of the deyen
erated (ihres pass to the stihstjintia iiiyra. Melius stiites that from a
half to nearly the whole of the dejreneratioii, foUowino- h'sion of the
thtmdi centre, which extends tis far its tlie cerebral peduncle, ternii
nates in the substantia niyra. At the pyramidtil tleciissation in the
medtillii the niajoriiy of the libres cross ovei- into the lateral pyraiii
idal tract of the opposite side, iiUhotiji^h a few ifo down in the hit
era! funiculus (Fiy. (iriOi. and still fewer in the ventral funiculi of
tlH> siiine side. It is interesting- that the degenerated fibres do not
stop in the upper cervical levels, but, as nii<;ht have been expected
from the experiments of Ferrier and Yeo. beyin to leave the while
matter frt)m the level of the seventh cei'vical root dowiiv ii'd, the
deofonerating' fibres stetidily and (>-ra(lualIy disappear! ny liy tiiniiiii,''
into the gniy in;itt«'r until at the level of the thiril liioracic root no
deg-eneriited fil)res reniiiin.
It would take too lout,'' to describe all of the experiments made
by Melius in connection with the facial area of the cortex, but in
rf\t
* „
(UIOUIMNO AND CllAININ(i TOdKTIIHIt OF NKl'liONliS. l()._>9
I
60
2
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«2.
i
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§
S
a
1
8
1
*-4
w
s
a
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o
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Till'] NKK vol's SVSTKM.
aNiiiurli as \w worked principally with the cortiral area correspoiid
iiitr III the iiMitor rcpri'si'iitatioii Tor opening the timiith slrai^fht, Imh
results after exiirpalioii of this area may he hrielly deserihetl. The
usmK-iatioii lihres t'nuii this area were carefully studied as well uh
l''i(i. liW. — l)t'K<'ii('i'ut('il aifii ill Fit', ""il. I'nliU'Kcd. (I'liiitn-iiiici'iiLM'apli liv K h
M.lliis.i 1 ^ ■ .
the projeetiou Hbres. As rejfards the latter, holli fine and coarse
fibres degenerated, the fine fibres teriniiuitin<c in the thalamus, the
coarse (tihresof the pyramidal tract) exti'iidinjr through the anterior
portion of the capsule (in its upper levels) and tlie middh' third of
the postei'ior limb of the capsule (in its lower levels) (Ki<;s. (("if
and t!iV^) to enter tlu> cerebral peduncle. In the cerebral peduncle
the fibi'es are scattei'cd evenly over the middle third of the area, as
.seen on cross section, encroaching a little upon the latei-al third
( Fijfs. C),*).'? and (554). Some fibres leave the ti-aet here to term inate
in the substanti;i niyra or in the hyiiothalamic region.
Farther down the remaining degenerated fibres begin to leave
the {)yraniidal tract at the jun<"tion of the ptms and medulla oblon-
gata, and singh» di'generated fibres coidd be follow<'d to the niudeiis
nei'vi facialis of the same side ami of th(> opj)osite side to the motor
nuclei of the N. ghissopharyngeus aiul X. vagus of both sides.
Melius em|)hasizes the fact that all the degenerated pyramidal
fibres from the hallux and thumb regions <Miter the internal capsuli'
at or near its posterior exti-emity, while the con-espondiiig fihris
from the lesions in the facial area enter tlie capsule at or near its
anterior extremity. The former fibres become displaced forward
at lower levels, the latter backward, mitil in the lower levels of
IL..
nH(>lTl»IN(J AND l'IIAININ(J ntOKTIIKK OK NKUHoNKS. l^yi
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1032
TFIK NKKVOirS SYSTPIM.
ilic iiilcnial capsul*' the film's arc all crovvdcMl f(»{rotlior at al»()nt tlii'
iniddlc thin! of tiic jjostcrior liiul). '" It is also shown that a liin
i-aii Ik' drawn from the lissurc of Sylvius forward, so dividing the
motor area into two parts — that of the facial lesions from which
lihrcs enter the anterior portion of tlu' capsule would he in the
anterior division, and all the hallux and thumli lesions from which
lihrcs enter the posterior portion of th(! capsule would b(^ in the
.. ;l|
Flii. (jr)4.— nojjoncraU'd aivii in Fift. (i53, ciilivrKcd. (PhottMnicrogr.ipli iiftn
Melius.)
posterior division. Tn the movement of the facial fibres backward
between the u])])(>r and lower levels of the capsule they would
neces.sarily, at sunie iev<d, envelop the {JTcnu. which would account
for the fact that they have always been described as occupying that
l)osition." The strikiiifi' ayi-cemenl of the lindinti-s in these cases of
♦•xperimental dejjeneration with those followinjif upon tdectrical
i'xcitatioii will be clear if the two Ix^ <'ompared witli one another
(rith' siii)i'(i). Melius emphasizes the fact that in the ba.se of the.
<.'erebral peduncle in the monkey the facial fibres are mi.\ed up in
(JIl()rPIN(J ANT) rilAININd T()(JKTIIKll OF NKI'IIONKS. jo^y
tht> middle tliird (if the arcii, as seen on cross section, and do not
<)ccui)y a si>acc by themselves medial to tlie lihres of tlie pvminidul
tract.
The significiiiKH! of the uncrossed fibres of the inramichil tract
is somewluit tliflicult to understaiul. Now thiit we know that a
certain number of tibres remain uncrossed even to their termina-
tion, and the i)roof has been brou<;ht that eatdi cerebral hemi-
sphere staiuis in connection with the groups of lower motor
neurones on both sides of the rliombeneephalon jind spinal cord,
it docs not seem unlikely that in the uncrossed fibres we may
find the anatomical explanation for tlie jihysioiogical itecuiiari-
ties of the so-called bilaterally innervated movements. Jt is iu)t
impossible, too, that herein is to be sought the explamition of
the curious behavior of the so-called residual jtaralyses after
cerelu-al liemiidcgia, wliicli have I)ecn ably descrilu'd by Wcrni(!ke
and Mann, of lircslau. The cases of hejnii)legia following homo-
lateral lesion of the brain have also to be thought of in this
connection, tliough it is not yet clear that the explanation of
this unusual plu'nonu'non is to be found here.
Tlu' light tlirown upon i]u> upper tnotor neuroiu's by studies
undertaken witii tlu^ nuUhod of (iolgi concerns mainly (1) the
interrelations of the cell bodies and dendrites of these neurones
with one anotluM*, aiui with those of other neurones in the cere-
bral cortex ; (2) tlie collaterals given oil by the axones of these
neurones in various i)arts of their course; and (3) the terminal
relations of these axones.
For the interneuroiuil relations in tlie cerebral (!ortex the
reader is referred to the studies of liamon y C'ajal.* His scheme
is reproduced in Fig. (lAr).
The studies of Starr, Strong, and licaniing include investiga-
tions in this area. In Fig. (iali their scheme is shown.
As to the collaterals given off by the axones of the pyramidal
tract a number arise in the first place while the axones are still
in the cerebral cortex ; others are given off shortly after their
entranca^ into the corona radiata. In the jions, collaterals from
tlu; jiyraniidal tract are distributed to the nuclei pontis. In the
gray matter in which the axones of the pyramidal tract terminate
♦ Ramon y Oajiil. S. Tjcs noiivollos idt'cs sur liv structure (hi systoiiii'
iiiTvcux cho;'. riiomiiic ot ciioz ies vi!rti'brt''s. I'ur. (iloimwald ul (."ic), (18!)4),
1)]). :ifl-G9.
J
I
1034
THE NKHVOUS SYSTEM.
many colliitenil branches are given off; indeed it may be said that
the axoiies become exhausted through the projection of numerous
coUaterals.
Ki(i. t),').'). -Sflicmc slidwiii;; the in'olialitc ('oiirsc <>( iiiipulscs and tlic iiitcfiii'ii-
roiial coiiiH'clidiis ill tlv cortex ('crcljri. (ACtiT S. Haiiioii y Cajal. Lcs
mmvcUcs idrcs. ctf,, Azimlay, Paris, IWII. p. (iti, Kif;. l(i.) .1, small iiyraiii-
idal cell; />, larfif pyramidal cell; ('. />. piplyiiinrplious cells: /'.', terminal
<'eiitripelal prujection tiltre ; /'', collaterals from the siiltstantia alba; fr, axone
liil'iircatiiiK in the suhstanlia allia.
A ,1' -
V
It is liighly desiniblc tluit tlie exact terniinal rehitions of the
axones of the iii)})er motor neurones be more thoroughly stiuliod
by means of the method of (iolgi, for we find in the bibliogriiiiliy
two diametrically opposite views with regard to the relations of
the terminals of these iixonos of tlie cell bodies and dendrit(\s of
the lower motor neurones. Von Monakow * believes thiit the
* voii Moiiakow, ('. Rxperiint'iiti'lie uiid piithdlojjiscli-iumtomiselio Tii-
terstic'liimgeii iielierdie Ilaulioiiivjjrioii, dcii Seliliii^fel uiiil (he Refjiosiiiithaia-
inioa. ncbst TieitriiprkMi znr Konntniss frilli erworlieiu'r (iross- iind Klpiiiliini-
defecte. Arcli. f. I'sycliiat. \i. Ncrveukr., Herl., M. xxvii (18!)")), S. 1 ; 'Ml
.:sB3?aai .1. iii"«i"
III
A
w
GROU
i
i
Fl<i. ()5(i. — niiiKi'iini of tlic ct'lls of the cerebral cortex. (After Starr. Strong, ami
LcaniiiiK, .\tlas of Nerve Cells, New York, IWIfi, p. 7^, Vifi. 10. i /, siiper-
licial la.ver; a, fiisiforin : /*, triangular; c, polygonal cells of Ramon y Cajal •
//, la.ver of siiiall pyramids; il. smallest ; c. small ; ./', medium-si zed p.vraiii-
idal cells with axones desceiidiiij; to the white matter and Kivin;; otf 'dl-
laterals in their course: ///, la.ver of lar^e pyramidal cells; <i, larjjest if,'i!Uit>
liyi-aniidal cells: k. larjte pyramidal cells with very numerous dendritt's ; :ill
pyramidal cells are seen to send lonj; ai)ical dendrites up to / ; m, .Martinotii
cell with (leseendinH <iendrites and asccndiu}; axone ; », polygonal cells; /!',
dee|i la.ver; /), fusiform cell ; r/, polyjional cell ; I', tlii' white matter <dntain-
h\li the axones from the pyramidal cells <l, c, /. ;/, and from a cell of the (leeii
layer (/ ; r, neuroglia fihres.
///
.K^
/y
Y! if
GROUPING AND CHAINING TOGETHER OF NEURONES. 1035
//
///
ly
\\
I
H
103«}
Till-: NKRVOUS SYSTKM.
axonos of the iiyramiilal tract in all probability do not enter into
direct conduction relation with the lower motor neurones at all.
lie is of the opinion that in between the upper motor neurones
and the peripheral motor neurones are intercalated dendraxonos
{(iolgi cells of Tyj)e II, von Monakow's SchnUzeUen). \\y means of
these demlraxoues the peripheral motor neurones are aj^gregated
into groups, so that one or more pyramidal axones acting upon the
dendraxone could set into activity all the nu)tor neurones recpii-
site to innervate the muscle fibres concerned in the jjroduction of
a given movement. By means of this intercalation of dendrax-
ones von Monakow would account for the production of so nuiny
different movements with so limited a number of fibres as the
pyramidal tract contains. This highly ingenious view is not
purely theoretical, for von Monakow states that in his extensive
series of secondary degenerations of the i)yramidal tract he finds
that the degenerated fibres do not extend into the ventral horns
of the spinal cord, inasmuch as the substantia gelatinosa does not
atrophy and disappear there. On the other hand, there is with
lesion of the pyramidal tract a disappearance of the substantia
gelatinosa in the region of the processus reticulares near tiie
lateral horn. Von Monakow, therefore, suggests that in this part
of the gray matter are situated the dendraxones which receive
the impulses directly from the fibres of the pyramidal tract, and
which by means of their axones in turn distribute them to the
dendrites and coll bodies of the lower motor neurones. This
view of von Momikow has been supported with a good deal of
vigor by Uedlich.*
On the other hand, von KoUiker assumes that, taking into
consideration the number of collaterals given off by the terminals
of the axones of the j)yramidal tract, the total number of til)res
coming into relation with the lower motor neurones is quite
sufticicnt to account for the liberation of the impulses concerned
in the various voluntary movements witliout the assumption of
the existence of intercalated dendraxones. For the j)resent it
seems wise to leave the question o))en. \ most favorable field
for work with (Jolgi's method is here re])r> sented.
The whole conduction ])ath from the cerebral cortex to tlio
muscles, involving at least two sets of superimposed neurones, is
* Redlicli, K. Ueber die anatomisclieii FoljjpersehiMii'iiniiigiMi luisfjc-
dehnter Exstirpationen dor motorisf^heii Uitidcmjeiitroii bei (k>r Ivatze.
Neurol. Ceiitralbl., licip/., Hd. xvi (1H!)7). S. 818-832.
>•' 1^
(iU()UIMN(} AND CIIAININCJ T()(JKTIIKIt OK NKUIIONKS. 1(>;{7
sonictiiiics spoken of us tlu; cortic^o-inusciiliir (;ondu(;lion path
(Figs. <;:>; jind (;")8).
Wo owe to (iowers cspeciiilly tho rocoguition of the ditTerciicea
tU,o>v "<
//a//u» ^nJ%maH Jots
Gcp
«ia?,vi
MuScH
Fig. 657. — Scheme of upper aud lower motor iieunmi's. Ltttering as in Plate II.
m
1038
fl^^.
TUB NERVOUS SYSTEM.
O.cf.
I"i(i. (ir>s. Sihi'UK' (tf upjKT and lower tuotur iicurDiics. LctU'riiig saino a^ in
I'liitc I.
flUOUI'IXC} AND niAINING TOOETIlElt OP NEUIIONKS. [()'.]<)
P'ili'
in the effects of lesions involving on the one hand the lower
motor neurones and on the otlier the upper motor neurones.
Gowers described these us (1) lesions of the lower motor segment
and (2) lesions of the upper motor segment.
If the lower motor neuroiu-s be seriously injured there results
the so-called flaccid paral3sis. The muscles undergo rapid atrophy,
and exhibit the so-called eler "cal reaction of degeneration. On
the application of the galvanu; or the faradic current to the de-
generated nerve there is no response. Hut when the muscle is
stimulated, while tiiere is no response to the faradii' current,
there is a response when the galvanic current is applied, which,
however, is not that which nornuilly occurs. Instead of being
sharp ami (piick, the contraction is slow and lazy, ami, in oppo-
sition to the rule in health, the anodal closure contraction nuiy
be greater than that on cathodal closure. Since the reflex arc is
destroyed when the lower motor neurones are degenerated, the
so-called deep reflexes are in such instances abolished and the
muscular tension is diminished. The groups of muscles para-
lyzed give tiie clew to the localization of the lesion.
When the upper motor neurones — for example, those the ax-
ones of which correspond to the pyramidal tract — are degenerated
there is also paralysis, but of an entirely different nature. Instead
of the flaccid, markedly atro])hic ])aralysis of the muscles with elec-
trical reaction of degeneration, there occurs the so-called spastic
paralysis, accompanied, as a rule, by no more atrophy in the
muscles than that which would naturally follow disuse. The
deep reflexes in such instances are of course exaggerated, and
the tension of the muscle may be markedly iiun'cased. The dis-
tribution of the paralysis will of course be entirely difTerent from
that which occurs with lesions of the lower motor neurones, and
the situation of the lesion may be ascerfained by careful consid-
eration not only of the nature and distribution of the paralysis,
but l)y a consideration of the accomiiaiiying phenonuuia due to
associated lesions in other Jierve paths.*
* Cf. Sccttioi) on Nervous Diseases in Osier. W. Prini'i|iles and Pnictice
of Medicine, :{(l ed.. New York ( I Si).S).— Gowers. \V. H. A Manual of Diseases
of tlio Nervous System. I'lniadelphia (IHUi).— Mills, (". K. The Nervous
System and its Diseases. Philadelphia (1898).
V!
%
*
ii
1 „ .,
CHAPTER LXIII.
IXTEUMEDIARY AND Ul'l'ER MOTOR XEl'ROXES (CONTINUED).
The frontal cerebro-uorticopontiil palli. or faseieulus pallio-frontivlis, pnr>
frontalis.
3. Those the Axones of which Correspond to the Frontal Cerebro-Corticopontal
Path.
Tins path, doscribed by Flechsig as tlie frontale Grosshirn-
rinde- Briickenbahu y is assumed by liim to arise in those regions
of the cerebral cortex which correspond to the distribution of
the system of sensory fibres which he designates as No. Ill ; that
is to say, the feet of the tliree frontal gyri, and possibly also the
middle jiortion of the gyrus fornicatus (Fig. 65!)). The axones
from the large pyramidal cells of this region of the somiesthetic urea
running in the centrifugal direction toward the internal caj)sule
become medullated at a period somewhat later than the fibres of
the pyramidal tract. The fibres pass through the pars frontalis
of the capsula interna near the genu, pass through the base of
the cerebral peduncle medial to the fibres of the pyramidal tract,
and, according to Flechsig, terminate in the nuclei pontis. It is
Flechsig's opinion that this frontal cerobro-corticopontal path is
concerned with the movements of bilaterally innervated muscles,
such as those of the eyes, neck, and trunk. The motor impulses
concerned in the speech movements may also, lie believes, be
carried by nbi'es of this path. There is a good deal of evidence,
however, that the speech path is se])arate and distinct from the
frontal cerebro-corticopontal path. By means of neurones
extending between the nuch ' pontis and the cerebellum by way
of the brachium pontis, the frontal cerebro-corticopontal path
throws the cerebellum under the influence of the opposite cere-
bral hemisphere.
In the pars basilaris pontis the frontal cerebro-corticopojital
path at first occupies the dorso-medial portion of the longitu-
1040
%' i^
OllOUl'INa AND i;iIAININ(} TOdKTllKU OF NKUUONKS. 1(»41
(linal fibres, but in more ciuidiil planes it turns ventralwanl, su
that it comes to lie ventral and somewhat medial to the libres
Oct.
N abducens'^ /
N. facialis.'
"«(,«»
irjiw
iN.C«r»J.
Flu. 659. — Scliemo of I'ronttil cirobro-cortictiiHintal path. Lettering us in I'liite II.
of the pyramidal tract (Fig. OGU). Tliis tract may degenerate
after lesions of tlie middle and inferior frontal gyri, in wliich
event the dorsal bundle of the anterior limb of the internal
capsule undergoes secondary degeneration, and the frontal cere-
t '!
1042
TIIK NKltVOrs SYSTKM.
r
M I
i ■ I.;
F i
ji i'K
?' ^' I
' ^ ' i
Fks. (itil. — Sccinidary (Icuciicnitiuii fdllowiiif; Icsiini in the Icf'l middle und infe-
rior rnmtiil K.vri ; the deKenerated IVontiil ( crelird-eorliciipontal path isshcpwn.
(After ('. von Monalvow. (itdiirniialh.dofjie, Wien, ISitT. Fi^s. lS(i ls!t.)
A. TransTerse section at tiie h'V( I of the niiiidh' of tlie tlialannis passing;
through the nn(deus hypothalainiciis (I'orpus Luysi i ; in//, nn<deiis anterior
thaiaini ; ci, capsnla interna: CL. niicU'ns hypotliahiinieus (corpus Lnysii;
ijift. stratum reticulatuni ; //..•<//•. radiations from caiisule of red nuidens i llau-
henstraldunn) : /,;. /((^ nucleus lateralis thalaun ; /./, nucleus ientilornns ;
/w'.v(7i, ansi h'Uticularis ; mcd. nucleus nu'dialis thalami ; inril.il, deffcnenition
in nu(deus nu'dialistlialanii : /'('(/.(^ dejieiu'i-iited frontal cerel>r<i-corlicopoutal
path: I'ldAl'lir. liithii), fasciculi cerehro-spinales (jiynimidalesi ; nfr, nutdeiis
caudatus; iriit.nn/. nucleus ventralis (anterior) thalami; :i, zona incerta ;
/>'!', fasciculus thalamo-mammillaris Vic(| d'A/.yri. H. Transverse section
through the posteriiu' extremity of the thalamus and tlu' ret rolenticular
portion of the capsula interna; />'.l, Ui-iudiinm ciuijnnctivum : // .V. tractus
opticus ; /'(/;•, fasciculi cerehro-spiuales ( pyramidales ) ; I'nl, pediiucnlus cere-
liri, pars hasilaris ; A'A'. nucleus ruber ; '/'/(((/, thalamus: mil. ventral Kroupof
nuclei in the thalamus. ('. Transverse section throuj;li the pons ami .junc-
tiiui of the colliculus superior with the colliculns inferior: II. I, lirachium
conjnnctivum : />'c.l, lirachium pontis ; kcIi, lemniscus. I). Transverse sec-
tion throu<;h the uppermost part of the medulla olilon^ata ; de;;enenition no
huiKcr demonstralile : llr.l, l)ra<hium pontis: ///,. t'ascicnlus lonKilmlinalis
inedialis ; ()l. inuleus olivaris inferiiu' : srli, stratum iuterolivare lemnisci ;
17 A', nucleus N. alxlucentis; 17/, radi.v N. facialis pars .secnnda ; 17/ A',
mudeus N. facialis; I't/r, pyramids.
I
GROUPING AND CHAINING TOGETHER OF NEURONES. 1043
si'' ,1 lot
tcntant
vcn
PtdiPyrl'nhn)
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vent ^^^^^^ff&^^^^-C:'''^
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TIIK NERVOUS SYSTKM.
in :;
I It? I
J
•*, !
bro-corticoponhil path can be followed into the most niedial
portion of the base of the cerebral i)e(liiiicle. In such instances
the ratiiation of the nucleus niedialis tlialanii and a portion of
that of the nucleils lateralis thalanii atrophies, and after a time
disappears (von Monakow). An example of degeneration of the
frontal cerebro-corticoimntal path is shown in Fig. Wl. 'J'Jiis
bundle, esj)eeially in the base of the cerebral })edun(>le, has been
called, though iinproi)erly, Arnold's bundle.
Zacher * has recently denied any connection between the
frontal lobe and the medial segment of the base of the cerebral
l)eduncle. In his case, in which the medial bundle of the pes
was degenerated, the anterior portion of the posterior limb of the
internal capsule was entirely free from degeneration, lie believes
that the medial bundle of the pes has its origin in all probal)ilitv
from fibres which run in at the base of the nucleus lentiforniis in
its posterior part from the outside. These fibres, he believes, in
part at least, have their origin in the island of Keil. Dejerine
attributes the origin of the fibres to the Holandic operculum and
adjacent part of the frontal operculum. One of Spiller's f cases
would indicate that at least a })ortion of the bundle has an origin
anterior to the Holandic operculum.
* Zacher, T. Beitriigc zur Kenntniss des Faservcrlaufes im Pes pedumiili
sowie ucber die corticaloii nezicliuiigeii iles (\(ri)iis jsreiiiculatiiin internum.
Art'h. f. Psychiat. u. Nervenkr., Herl., Bd. xxii (1890-"!)1), S. G54-6!)8.
t Spiller. W. (t. A ("oiitributiou to the Study of Secondary Depeiieratinn
fdllowinj; ('(>rel)ral Lesions. Trans. Am. Neurol. Assoc, 1897, New Vmlc
<18i)8), pp. 310-338.
)
CHAPTKK LXIV.
TXTKIfMI'.niA WV AND riM'KIl MOTOU \ Kl'KC/N KS ((ONTI MKO),
I'lic Ifiiiporal cercbro-corticopontal path — Paths from the lohiis oi-uipitalis
to the corpora quadrijjcinina — Olfactory roflox pat lis.
4. Those the Axones of which Correspond to the Temporal Cerebro-Corticopontal
Path.
TifKSE are tlio noiiroiios the iiiecliilktod axonos of wliicli
occn])y tlie most latofal segment of tlio base of tlio corobral
poduiicle designated by Flechsig as the tempornle Grosshiriiri/Klc-
lirurkenhnhn. The bundle is usiitilly called Tiirck's bundle,
quite impi-operly it would seem, since the bundle concerned is
separated by a wide area from the region found diseased by
Tiirck in hemiani\3sthesia.* Flechsig believes that the cell bodies
luid dendrites wliich give origin to the axones of this path are
situated in the auditory sense area of the cerebral cortex (gyrus
tenijioralis superior et gyri temporales transversi). The axones,
he believes, pass down through the posterior jmrtion (retro-lonti-
form portion) of the pars occipitalis capsuhe interna; to the
lateral region of the base of the cerebral peduncle. Thence they
go into the pons and eiul there in some way unkiu^wn to Flech-
sig, perhaps, he suggests, -joing ever directly into transverse
fibres of the jmns or ending in the nuclei pontis. lie is inclined
to think that, like the frontal cerebro-cortioopontal path, this
temponil path represents ii mode of connection by way of the
briichium pontis of one cerebral hemisphere with the op})osite
cerebellar hemisphere. The fibres are medullated at a later
])eriod than the fibres of the pyramidal tract.
Von Monakow describes the temporal cerebro-corticopontal
path as occupying, in the cerebral extremity of the pons, a dorso-
lateral lield, which it follows until it becomes exhausted in the
gray matter at the caudal extremity of the pons, except that from
t
k*
* Op. ril.
1045
,4'
(i
w
l(»4r>
TIIK NKUVOUS SVSTHM.
the middle of the pons on it is locjited exactly dorsal to the
librcs of the pyraniidiil tniet. The fibres of tiiis bundle, like all
the other fasei(aili longitudinales of the pars basilaris pontis, arc
separated from one another by fibne transversa; ])ontis and l)y liie
masses of <rray matter which make up the nucl(ji jjontis.
\ I
fi 111
Fk;. tit)2. — Zone of tlic (■crt'liral cnrlcx. Icsinii (if wliirli ciiusi's <l<'«<'n('rati<iii of iill
llu' tilinsof the Imsis iicdiinciili. { Aftcr.l. 1 hjcrine, froin A. van (^■lniililcii's
t(Xl-l)ook. I /, I'ortical cciilri' for the lowcT i'atial and the liypofilosMis ; //,
(•orli4-al (■(■Mill' for the iiiipcr <'xlicinil,v ; ///.cortical centre lor tlic lower
fxtreniily : /I', cortical centre for the lateral hnndle of tiie basis peclmiciili.
The fibres of the temporal cerebro-corticopontal ptith dejion-
erate in a descending; direction (Ziicher, Kam. von Montikow, and
I)ej(!rine). According to Dejerine,* the bundle arises from the
whole temporal lobe, but by no means solely from the gyrus
temporalis superior. Indeed, he favors the view that the fibres
arise mainly in the (i. temjKiralis mediiis and the (i. temporalis
inferior, ^loreover, Dejerine iisserts that the fibres on their way
from the temporal lobe to the base of the cerebral peduncle do
not pass through the capsula interna at all, but instetid go below
the nucleus lentiformis to join the other fibres whicli enter the
cerebral pedunclt! in tlie hypothalamic region. In Fig. fiOv' is
reproduced a diagram in which is shown thecortit^al zone, which,
when destroyed (according to Dejerine), will lead to complete
degeneration of all the fibres of the btisis pedunculi.
In this connection a case of the highest importance has
* Dejerine, J. Stir rorifjiiic (■orlieale et le trajet intnu'erebral <les lihres
do I'l'tiif^e iiiferieiir nil jiied tin pi'doiieule ('('n'lirnl. Coinpt. rend. Soe. dr
liiol.. Par., it. s., t. V (IM)).'!). pi. 3, pp. 1!t:i-2(l(i.
GHOUPT\(i AM) CIIAIMXO TCHlETIIKU OF NF.URONHS. 1047
recently been cjircfiiUy studiod by ^[ills and Spillcr.* 'I'liis caso
makes it diflicult to understand the view of Flechsijf, for it
seems liard to conceive liow in such a case, where tiuTc was no
de<^(MH'ration in the lateral bundle of the base of the cerebral
})eduncle, the fibres whicOi form this bundle coidd have their
origin in the gyrus temporalis su])erior (Klechsig). It seems
strange that the origin and distribution of the axones of the
hiteral buiullc of the pes have not been approached from the
experimental side. It is not too much to hope that we shall
soon have data to record in this connection, l-'crrier and 'I'urner
have extirpated the gyrus temporalis superior and have obtained
secondary degeneration in the lateral bundle of the pes, thus
supporting the doctrine of Klechsig, though their studies su])p()rt
Dcjerine in part, in that they ilnd that the fibres j)ass lateral and
ventral to the nucleus lentiformis.
fi. Those the Axones of which Connect the Lobus Occipitalis with the Nuclei
Governing the Movements of the Eyes.
Klecdisig, in his descrij)tions of the lateral bundle of the base
of the cerebral peduncle, thinks it probable that a certain num-
ber of the fibres of this bundle may arise in the visual sense area
of the occipital lobe. His views are supported by the embryolog-
ical studies of von Bechterew.f That there are neurones extend-
ing between the visual sense area in the occipital cortex and the
eye-muscle nuclei, or at least the superior colliculus of the cor-
pora quadrigemina, seems extremely probable from the studies of
secondary degeneration after animal experiment carried out by
von Monakow and the studies of anophthalmia conducted by
his students. Kx(!itation o( the cortex of the occipital lobe, as
Munk, Schaefer, llorsley, and others have shown, is followed by
movements of the eyes. Tlu; results of these researches render
* Mills, C. K., and W. G. Spiller. A Case of Cerebral Abscess Situated
at the Posterior I'art of the Kxtcrnal Capsule (involving the Medullary
.Substance of the First Temporal Convolution, also the Posterior Part of tlie
Lenticular Nucleus, and ext(Mnling into the Subthalamic Rej^ion), with
.Some Considerations in Regard to the Constitution of the Kxternal Rundles
of Fil)res in the Cerel)ral Peduncle. Med. and Surg. I{eporter, IMiila., vol.
Ixxiv (18i)(5), p. 742; also in the J. Nerv. and Ment. Dis., N. Y., vol. xxiii
(IH'Jt!), pp. (i22-(52H.
I von Rechtercw, W. Zur Frage ueber die secundiiren Degencrationen
des ilirnsehenkels. Arch. f. I'syehiat. u. Nervenkr., lierl., IJd. xix (1887),
S. 1-lT.
f
:^,l
1(»48
TIIK NERVOUS SYSTEM.
^1
? '
it probable that the giant innimidal cells of the third cortical
layer send their axones through the radiatio occipito-thalamica
(Jratioleti and the brachiiim (|uadrigeniinum siijK>rius to the
colliculus superior of the corpora quadrigctuiiui and the stratum
griseum cuntrale aqueductus cerebri. Wiictlier or not any of
these axones actually reach the nucleus iiervi oculo-motorii and
the other eye-nuiscle nuclei directly is not known ; it may be
that another neurone is interposcil between the terminals of the
<»ccipito-niesence{)halic neurone aiul the lower nu)tor neurones.
Indeed, this is the view which von Monakow is inclined to sup-
port, and it is quite in accord with the prevailing ideas with
regard to the superior colliculus, whiidi is geiu'rally looked upon
as the central organ for the governnunit of the eye-muscle luiclei.
That the fibres from the occipital cortex to the nu'scncephalon
do actually pass through the lateral segment t)f the cerebral
peduncle is made very probable by the studies of Zacher.* He
believes that the tibres from the occipital lobe are nu)st laterally
placed, those from the temporal lobe being situated between
these and the fibres of the pyramidal tract. The cases of 8ioli f
and Winkler | make it not impossible that some fibres from the
lol)iis i)arietalis also pass through the lateral segment of the base
of the cerebral peduncle.
6. Those the Axones of which Connect the Rhinencephalon with the Lower
Motor Neuiones.
These have already been dealt with in connection with the
olfactory sensory neurones of the second and higher orders, to
which tile reader is referred.
* Zaelier. T. |{i'itnij,'o /ur Keiiiitniss des Faservorlaufes im Pes pcdun-
cufi sowio iiolicr (lie I'orticiifi'ii Heziefiiiiip'ri des Corpus p'liiciilatuiii inter-
num. .Vrcli. f. iVyeliiat. u. Nervenl<r.. Merl., IM. xxii (lK!»()-"i)l). S. (5.")4-()!IS.
+ Sioli. Teber die Fasersysteme iin Fuss des (irossliirnsehenkels uud
Dcfrt'rieratioii derseihen. ('entrall)l. f. Nervenli.. Fieij)/.. lid. xi (1H8H). S.
438-441; also in P.nslau aerztl. Ztseli., Hd. x (18HS). S. 181.
|\Vinl<ler.(". Secundaire neerdalende defjeneratie van den nicest latenuil
Kele,<,'eii hnndei in den pars peduneuli cerebri (Den huiidel van TiirclO. \c-
derl. Tijdsclir. v. (ieneesli.. .\inst.. 2. R., xxii (188G), pp. 58o-r)91. Also see
Neurol. Centralbl. (1887). S. 2S!).
.M^
SUBSECTION V.
Projection Neurones, Commissural Neurones, and
Association Neurones of the Telencephalon.
It seems desiriil)lo to refer briefly to tlie main teleiicephalic
neurones by themselves. It is customary to divide tlie fibres in
the telenoeplialon into projection filiios, commissural fibres, and
association lil)res. The complexity of the fibres of different sorts
in the gray matter of tlie cerebral cortex is well illustrated in
Fig. G03. Now that we know that no white fibres exist which
have not their origin in cell bodies — that is to say, which are not
the axones of neurones — it seems more logical to speak of j»rojec-
tiou neurones, commissural neurones, and association neurones.
V
(A) Projection Neurones.
CIIAIT Kll LXV.
PRO.TErTIOX NEUROXES OF THE TELEN^CEPTTALON.
Groups of projiH'tioii neurones — Cercl)riil appanages or dependencies —
Phylogeneticaiiy young parts of tfie brain.
By these are understood the neurones which connect directly
the cortex of the telencephalon (pallium and rhinencephalon)
with lower portions of the nervous system. The medullated
axones nuiy ])ass in either direction — from the cortex to lower
centres, or from lower centres to the cortex. In the former in-
stance the cell bodies of the neurones are situated in the cortex,
ami the axoiu\s descend — that is to say, the conduction is cortico-
fugal. In the latter instance the cell bodies of the neurones are
situated in the lower centres, aiul the axones ascend to termiiuite
ii\ the cerebral cortex. The latter are corticopetal in conduc-
tion.
1049
-1:
1050
THE NERVOUS SYSTEM.
e.z,
?■;•
HM-
<'i(i. ()(«{.— ("ortcx oflimnan brain illustrating the systems and plexuses
fil)rcs icdiuMiiation (if the metlintis of Weifjert and (icilfii ). i After I
ezen, Hntin, Lund., vol. wii, 18!»4. i r.-., clear zone free from nerv
M.I'., Kxner's plexus in the nioleeidar layer; L.tfr.. aniliinuus eell f
N«/>wi./'.. suhnioleeular plexus; O'/. /'./'., ^reat pvraniidal i)lexus ; J'ol.
nuiriduc plexus ; 11'., white niatt4'r.
of tiervc
J. Atidri-
(' (Hires ;
^lllllllii :
/'., poly
Y-'
I'
kl
.jU>
«KOUPIN(J AND (ilAlNING T<)(1KT1IF,1{ oF NKrUONKS.
i(»r>!
Tlic majority of those neurones liiive alreiidy been described
in connection witli (1) the sensory neurones of the hijj;her order
and (v) the upper motor neurones. Thus (a) t\w diencephalo-
toleneephalic neurones of the general sensory patli, (/>) the radia-
tio occipito-thahimica (iratioleti of the visual conduction path,
ami (r) the radiatio corporis geniculati niedialis of the auditory
conduction path represent corticopetal projection neurones.
Again, the libres of (</) the pyramidal tract, {/>) the frontal cere-
.♦.V-^'-'^ ^i"' j-
Fig. 6(54. — .Siifriltal section N'o. Its, tliroufih the Iiraiii uC a liahr sliorlly aftor
birth, illii^tratiiif; the impjcctioii til)rcs to the soiiiii'siiu'lic area. C.i., caiisiila
intcriiii ; (l.c.ii.. fiyn\s ('ciitralis anterior; (1. r. ii. , fiyrns centralis j)osterior;
/,()/). friiiit., lolms frontalis; l.oh. iiicii}., lol)ns occiiiitalis ; 'I'll., tlialanins;
'/'.((.. tractiis optiens ; .■;, nueleus Ivnlil'orii'.is ; ;■, corpus KOiiiailatnni lalenile ;
v. I., ventricnlns latenilis.
bro-cortieopontal path, (r) the temporal cerebro-corticopontal path,
and (d) the fibres running from the occipital lobe to the mesen-
cephalon represent the axoncs of corticofugal ])rojection neu-
rones. The ease with which these projection axones can be fol-
lowed in the meduUating brain is well illustrated in Fig. 004.
If an area of the cerebnil cortex be extirpated, especially in
the young animal, the axones of projection neurones, whether they
bo corticopetal or corticofugal, undergo a change. In the case
of the corticofugiil tixones secondary degeneration with absorp-
tion rapidly takes place ; in the case of the corticopetal axones
(!!1
I H It
11
II
'■r-'!
I
:ii*
i'i.
I
Id;') 2
THE NERVOUS SYSTKM.
there is less rapid (leyeiierutioii or utropiiy, which can be traced
to their infracortical origin. Tiiese infracorticul areas in wliieh
the corticopetal teleiicephalic ])rojection fibres originate, and
which, like the fibres tiiciiiselves, undergo atrophy or degenera-
tion after extirpation of the area of the cortex in whieli tiiev
terminate, are known as " cerebral api)anages " or " dependencies."
\'on Monakow has recently paid a good deal of attention to these
areas, and has described tlieni under the term (irosshirnantheile.
He believes that they are phylogenetically young, for they are
absent in lower forms, and increase progressively in size and num-
ber in direct proportion to the development of the cerebrum.
According to his view, the majority of the nuclei of the thalannis
and geniculate bodies, the substantia nigra, and portions of the
corpora (piadrigemina and of the pons belong to this category.
The various cerebral dependencies are of different age, as far as
can be judged from })hylogenetic studies, the olfactory organ,
the visual sense, and hearing having been successively developed.
(B) Commissural Neurones.
ClIAPTKU r.xvi.
il
COMMISSURAL NKIROXKS OK TlIK TKLEN(^EPII.\LON.
Ilptoromoric t('l('n('('phali<! lu-urones — Hccfateromcric ncu roues — Cnrinis
Piillosimi — ( '(»iimiissiirii aiitiTior (•(■ri'l)ri — t 'oimiiissiini liipi iini|ii.
Ry those are inoiint tUMironos with coll bodies situiitod in one
hemisphoro of the i.loncophiilon, while their axones are distrib-
uted in the cortex of the opposite hemisphere. They nii<,dit,
therefore, well be designated the intrinsic hetoromeric tolon-
cejihalic neurones. Studios by (Jolgi's nu'thod go to show that
some of the axones bifurcate, one of the limbs of bifurcation
p.assing into the opposite hemisphere, the other being distributed
in the hemisphere of the same side. Such neurones might well
bo called intrinsic hecateromoric teloncephali(! neurones.
The main groups of neurones here to be considered are (1)
those with axones corresponding to the medullated white (ibres
of the corpus callosum, (i) those with axones correspoiuling to
the fibres of the commissura anterior cerebri, and (3) those with
axones corresponding to the commissura hippocampi.
V'
1. Those the Medullated Axones of which correspond to the Fibres of the CorpuB
Callosum.
The fibres of the corpus callosum represent the axones of the
majority of the intrinsic commissural neurones of the tolon-
cephalon, and it has been well designated the rommissvrn maxi-
ma. The main body of this is known as the truncus corjwris
callosi. The anterior border of the truncus bends sharply down-
ward to form the genu corporis callosi. As a result of the curva-
ture there arises a ventral horizontal piece of the corjuis callosum,
about two centimetres in length, which, on median section, looks
wedge-shaped. This is the so-called rostrum corporis callosi.
1053
. J
1(154
TIIK NKIIVOUS SYSTKM.
Its tliiii, Tnoiliilliitod, k'iilliko extremity, oxtondiiig bin.'kwiinl ir,
the himiim teriniimlis, is known as the luininii rostnilis. At its
posterior border tlie truncus goes over into the nuicii-tliickont'd
spleniuni corporis (lallosi.
'riieaxoncs of wiiicli tluM'ori)tiscall<)siiMi is fornu'd pjiss in Ijoili
directions, some going to und some going from each of the ccrc-
l)ral liemispheres. Tliese converging and diverging fibres form
what is known as the raUiatio corporis callosi ; that ))ortion of ii
corresponding to tiie lobiis frontalis is known as the pars fron-
talis of the ra<liation. In tiie same way there is u ])ars parietalis,
Kki. titii). — ScliciiK'of a triiiisvcrsc section throiiKli the liriiin showiiiK tlic picilinhlc
(lisposilioii of tlif (•iiiuinissural anil piojccti'in litres. After S. Hanxpn v
Ca.jal, liCs nouvelles idi'es, etc., A/oulay, Paris, IS'M, p. (iO. Fi^. 15. i .i,
corpus callosiini ; />', eoiniiiissura anterior eereliri ; I', fasciculi cerelirospinalcs
(pyrauiidalesl ; n, jiyraniidal cells Kivint,' rise to axones of pyraniiilal tract;
oiw senilinK a linili of hi furcation through tlie ccu'pus callosuin to t lie opposite
lieniisphere ; h, pyianiidal cell .sending axone through coriius callosuni ; c,
liyraniidal cell with an a.xone wliicli Idfiirciites ; one noiiifj tlirouj.'li liie
corpus callosuin to the ojiposite hemisphere, the other lieiiiK distriliuled to
the <'ortex of the heiuispiiere of the siinie side: </, collaterals from callosiil
lihres; c, terminals of callostil tilires.
a pars temporalis, and a pars occipitalis. The tapctum is also
considered by mtmy to form a portion of the radiation of the
corpns callosuni, although, as has been seen above, recent investi-
gations are in opposition to this view.
The cell bodies which give rise to the axones of the corpus
callosum are, Kanion y Cajal believes, those of the small or me-
dium-sized pyramidal cells, or the polymor])hou8 cells of the cere-
bral cortex. It may be that some of the axones helping to fortn tin;
corpus callosum are collaterals from the axones of long association
neurones, or even of the axones of projection neurones (Fig. (Kif)).
ftf
Jl J^.
UIIOUI'ING AND ClIAlNINd TOdKTIIKH OK NKUUONES. 1^55
Studies of Hi'('()ii(liiry (Icf^t'iieratioii iiidiciito that tliroujjh tlio
forpUH t'lillo.siim tim m^tivitii's of u given rcntrc in the ciTobral
cortiix of on(i side are asso(riated witii the acitivities of a precisely
simihirly hx-iited cortical areu in the opposite cerebral hemi-
sphere. Hamilton * is of the opinion that the fibres of the corpus
callosnm after pas.siii<:f into the opposite heinis]dien^ do not go out
to the cortex of that hemisphere, Init pass directly downward
into the internal capsnle and parts below. He believes, however,
that the cell bodies of these axones are situated below, and that
the fibres pass up tiiroiigh the internal capsule and tlien through
the corpus eallosuni into tlu; opposite hemisphere. Thus impulses
would pass along them from the lower centres to the liigiier,
which are of signillcance in educating the motor cortex — that is,
serve as u means of conveying imi)ulse3 to arouse the motor area
of the 'M'ain. Tliis view has not as yet receiv(Ml the general sup-
l)ort of neurologists, and the extirj)ation exjieriments of Melius,
.Muratow, aiul others do not tend to coniirm it. Ferrier and
Turner, however, in a recent article seem to support, in part at
least, the hypothesis of Hamilton.
2. Those the Medallated Axones of which correspond to the Commissura Anterior
Cerebri.
This bundle of medullated axones is situated just in front of
the columnu! fornicis as they plunge into the tuber cinereum. It
is in reality situated in the region of the diencephalon, but the
cell bodies, which give rise to the axones which constitute it, are
situated in the telencephalon, ])artly in the rliinencephalon, ])artly
in the pallium.
The anterior commissure can be divided into two ])arts — (1)
a pars anterior and {'i) a |)ars posterior (Fig. CM')). The pars
anterior belongs apparently wholly, or almost wholly, to the rlii-
nencephalon connecting the olfactory cortex of one side with that
of the other side. It is much larger in numy animals, especially
in niacrosmatio mammals, than in man. "^rhe par? anterior
atrophies in toto after extiri)ation of the bulbus olfactorius on one
side (Ganser), or after extirpation of the lobus olfactorius of one
side (A. Meyer).
* Iluiniltoii, D. J. On tlie ('orpus Cullotsuin in the Adult Ilunmn lirain.
J. Anat. and Pliysiol., Lond., vol. xix (1884-"8r)), pp. 385-414.— On the Striic-
t lire and Functioiiiil Sisitiiricance of the Human Corpus Callo.suni. [Sum-
mary], I'roc. Hoy. Soc, Lond., vol. .\.\.\vi (188;>-"S4). p.
Mm
\)
I
i.'
lOaO
tup: nervous systp:m.
1
Tho pars posterior of tho iinterior coiuniis.suro is believed to
associate the activities of a portion of the temporal and of tlio
basal part of the occipital
lobe of one side with thosi;
of similar cortical areas on
the opposite side. In devel-
opmental stages of the or-
tfaiiism the pars posterior
of the anterior comnnssure
stands in intimate relation
to the ventral portion of the spleniuni corporis callosi, si'ul is
really morpholojjically widely separated from the pars anterior.
The view is ])revalent that the commissura anterior cerebri is a
snpplement to the corpus callosum, its axones originating and
terminating in areas of the cortex unprovided for by that body.
The comparative anatomy of the structure has been studied l)y
Osborn,* C". J. and ('. L. llerrick,+ Edinger,J Smith,* Syming-
ton,! '^^^ by Adolf Meyer.'"'
Fin. (ititi.— .S'luMiK^ of tho coniinissiii-n ante-
rior cerebri : /)./., pars posterior; y."..
pars aiileiior. (After A. Haulier, Lelir-
liiieli cler Aiialoinie des Meiiselieii, \' .
Aiill.. M. ii. Leip/,., 1S!)H. S. :5SS, Vin- 3:5(i. )
* Osborn. H. F. The Origin of the Corpus Cnllosum, a Contrihution
upon the Cerebral Commissures of the Vertebrata. Morphol. Jahrb., Leipz.,
B(l. xii (1M86-HT), S. 2'.]3; '>;!().
f Ilerrii'k, C. J. The Cerebrum ami Olfaetories of the Opossum Didel-
pii ,s Virjiiniana. J. Comp. Neuml., Cincinnati, vol. ii (1802), jij). 1-20.— The
Commissures and Ilisloloj^y of tiie Teleost iirain. Anat. Aiiz., Jena, Md.
vii (1891). S. G76-(iSl.— Additional Notes on the Teleost Brain. Anat. Anz.,
Bd. vii (18J)2). S. 422-4;{l. — The Callosum and Hipiiocampal Region in Mar-
supial and Ijower Brains. J. Comp. Neurol., (iranville. vol. iii (1H!);3), pp.
171-182. — Also C. Ii. and C. J. Herrick. Contributions to the Morphology of
the Brain of Bony Fishes. J. Comp. Neurol., vol. i (18!)1). p. 211 ; 3:53; and
vol. ii (1S!)2|. i.p. 21-72.
J Fdinger, L. Vergleiciiend-Rntwickelungsgeschichtliche und anato-
misehe Studien im Bereich der Ilirnanatomie. Anat. An/... Jena, Bd. viii
(1893). S. 3()r)-321.
* Smith, (t. E. Notes upon the Morphology of the Cerebrum and its
Commissures in the Vertebrate .Series. Anat. An/.. Jena. Bd. xi (IBO.'i), S.
91-96. — Morphology of the True jjimbie Lobe. Corpus Callosum, Septiiiii
Pellucidiun, and Fornix. J. Anat. and Physiol., Lond., vol. xxx (1895-'96),
pp. l.')7; IS.'); 450.
II Symington. J. The Cerebral Commissures in the Marsupialia and ]Mono-
tremata. J. Anat. ami Physiol., Lond., vol. xxvii (1892-93), pp. 69-84.
■''Meyer. .Vdolf. ('(^ber das Vorderhirn einiger Reptilieti. Tnaug. Diss.,
Leipz. (1892), S. 1-73 — Zur llomologie der Fornix eommissur und des .Si>p-
tum lueidutn bei deu Reptilien luid Silugern. Anat. Anz., Jena, Bd. x
(1894-'9r)), S. 474-482.
OUOUPING AND CHAINING TOGETHER OF NEURONES. 1057
3. Those the UeduUated Axones of which correspond to the Fibres of the
Commissura Hippocampi.
This ill in.iu and iiiiiininiiLs consists of a bundk- of niodnllatcd
axones extending between tlie crura foniicis of the two sides and
connecting the hippocampi witli one another. Fibres run in
both directions, forming apparently a true commissure, tlie so-
called psalterium or lyre of David. It can be divided into two
j)arts, one more dorsally, the other nujre ventrally located. This
is especially true of the commissura hippocampi of animals. The
axones probably have their origin in the pyramidal cells of the
hippocampus.
\l
-^
i
•!''i
m
(C) Association Neurones of the Telencephalon.
CKAPTEK LXVII.
ASSOrr.VTIOX XKIKOXES ok TIIK TKLEK( epiiai.ox.
Tiiutumerif telencpplialic iKuiroiu's — Fibni' projiria' — Stratum calcariiiuin
Fuseicultis occipitalis pcrpcndicularis — Kascieiilns occipitalis truiisvcr-
stis ciiiu'i — Fasciculus occipitalis ti'aiisvcrsus jjyri liiii^ualis — Stratum
jmipriutu cunci — Tiic ciuf^ulum — 'I'iic fasciculus loujjitudiualis supe-
rior — The fasciculus uiiciiiatus — Association bundles of the fornix
Tlic ta[)elum.
TiTESE mi/rlit well be called the intrinsic tautomeric tcleneeph-
alic neurones. By them is to be understood neurones which
connect a portion of one hemisphere witli another portion of the
same. Tliese association neurones may be divided into (1) tlioso
with short axones and (3) those with long axones.
The association neurones with short axones include the fibrai
propria' of the cerebral <ryri.* Some of tliem are nuMlullatcd
very late. In many of tlie convolutions almost all the wliitn
fibres j)resent consist of these short axones. The sliortest axones
are most snperlicial ; tlu' longer ones pass deeper into tiie white
matter. They vary in direction corresponding to the position
and curves of the ditferent gyri. Tliey are evidently for the
purpose of co-ordinating tlie functions of neighboring gyri.
Hamon y Cajal believes that the axones of the association
neurones arise from the polymorphous cells of the smaller and
larger pyramidal cells of the cerebral cortex. They give off
nunuM'ods collaterals so that the excitation of one of tliese neu-
rones can lead to alterations in the neural activity of many otiuT
neurones situated in various parts of the cerebral cortex. .V
* These are the neurones the axones of which were descriheii as tihne
arcuata' by .Vrnold and as I'-shapcd fibres by Meynert. They inchule n\>ii
the external layer of tanfjential (ibn's. the so-called stripe of (ienm\ri. and
the su|ier-radiMl plexus of Ivlin^rcr in (he ext Tnal zone of the cortex as will
as the intcrrailial plexus situated in the deeper jiortion of the cortex.
inr)H
m
C4R0UPING AND CIIAININO TOOETIIEU OF NEURONES. I059
seheniiitic reprpsentation of Ramon y Cajal's views concerning
tlie association neurones is reproduced in Fig. liGI.
Fl(i. t)()7. — Scliciiic (if ail :iiitcr(i-i>ost('riiir section tlinmf;li tlic ccrcbniiii sliowiiiK
tlu> (lisiH)sitiiiii (>r tli<' axiiiU'S of iissnciiitidli iicurcnK'S which cciiiiicct tlic
liihiis frontalis witli tiic luluis occii)itaiis. lAftcrS. Ivainon y (ajal, l-cs
iHiuvcllcs iilccs, etc.. A/.onlay, I'aris. 1 Sill. j). .">!•, Kitf. 4. ) o, ^. c, i)yiaiiii(hil
cells : (/. tcniiiiial of an axone ; <\ collater;'l.s of associiitiuu a.vones; /, tilires
of corpus callosuui cut transversely.
1. Those with Short Axones.
Tlie short association neurones liiive been most carefully
described, especially in the occipitid aiul frontal lobes, by Wer-
nicke,* Saclis,t Vialet,! and Dejerino.*
Among these may be mentioiuMl for the occipital lobe :
(1) The stratuHt cidatrinum (Fig. 0G8), uniting the superior
lip of the calcarine fissure to its inferior lip by its shorter fibres,
and the medial surface of the cuneus to the inferior and meditil
surface of the gyrus lingualis by its longer fibres.
(^) The fnftciculiis ocripitalix irrfiailis, or perpendiciilarix,
of Wernicke, II uniting the superior border of tlie occipital lobe
to its inferior surface. As a matter of fact, it connects the gyri
occipitales superiores with the gyri occipitales laterales and the
* Wernicke, ('. Lehrbiieii tier Geliiriikriuikhfitcn fUr Acrzte mid Studi-
reiiile. Kassel u. IJerliii (1H81-S;}).
t Sachs, II. Das llciiiis|)lu'ireiimark dcs ineiiscliliclicii Grusshiriir.. I.
Dor Iliiiterliaiiptliiiipen. Lcipz. (tSi>'.i), p. iU, 4to. — Vortriigc iiebcr IJati uiul
'riiiitij^keil (Ics Or )ssliiriis uiid die Lelire vmi der Aphasie uud Seelcnbliiid-
iicit fiir Aer/.te mul Studirciidc. Uroslau, p. '^!IG, Hvo (lHi»;{).
X V'ialet, N. Los centres ceivbraiix do la vision ot I'apparoil norveu.x vis-
uol inlra-ceiebral. Par. (bSOIS). — Notc^ sur roxisteiioo a la jiartio iiifi'riouro
du lobe (iccipilal d'lin faisooaii d'association distinct, lo faisceaii transversalo,
dii lobulo liiijjual. ('(inipt. rend. Soc. do biol.. Par.. J), s., t. v (18!»a), pp. 703-
795.
• Dejerine, .1. .Vnatoniie des <i>nln>s nerveux. Par. (bSit.")), pp. 712-786.
I SlraUiin propriiiiii cDiivexitatis of Sachs.
yl
10^)0
THE NERVOUS SYSTEM.
L>
1:'
gyrus fusiformis. Anteriorly it extends between the gyrus iuuni-
laris and the gyrus temporalis niedius and the gyrus temporalis
inferior.
JtcS.
0, ^«
itrprU
Fici. 008. — Vi'i'tical tnuisvcrst' Sfction of the left occipital lobe to show the oriKiii
and course of the sliort association tiln-cs of tlic lul)ns occipitalis i partly
schematic). I After,!. De.jerine. .\natoniie des centres nerveiix. Paris, ls»t5, p.
7h:}. V'ijr. US'). I (\ cimeus : /(((-. libra' propria- ; Fli, fasciculus lonffitudiiialis in-
ferior ; J'thj r. fasciculus occi])italis trausversus K.vri linKualis ; /^•^', fasciculus
(K'cipitalis Iransversus cunei ; Fiis, tiynis fusifonnis ; /i<, sulcus occipitalis;
A', tissura caUarina; /.;/. fjyrus liufiualis ; /(/, sulcus of j;.vrus liunualis ;
Oi, "2. "a, syri occipitales; (z^, sulcus oceiiiitalis ; Or. fasciculus occipitalis
verti<"ilis; iit, tissura collateralis ; /(d. tissui-.i parietalis occipitalis ; ncl ij, tiyruA
profundus contU'<'tiu}; cuu<'Us with the fj.vrus foriiicatus ; liTli. railiatio oc-
ciliito-tlialaiuica (initicdeti ; sll. stiipe of Haillarjjer ; slrK. stnitiiin calca-
rinuiu • KtijirC, stratum |)ropriuui cunei; '/Wy), tapetuni ; 1', ribbon of Vic(i
d'Azyr; I'oc, coriiu posterius veutriculi lateralis.
(3) The faxcirii/its orcipitalis tranxversvs cunei* extends
from the superior lip of the calcarine fissure lateralward and
• Stratum eunei tran.sversum of Sachs.
GKOUPIXO AND CHAINING TOGKTIIKR OP NKl'RONKS. loOl
w^
m
then curves uj)\vjird iiiid probably tcrmiiiates in tlie nortox of
the convex surface of the occipital lobe. According to Sachs,
some fibres go obliquely forward and iatonilvvard to the lobulus
parietalis superior and the gyrus angularis.
(4) The fascifidiis occipitalis frtinsccrsiis (ji/ri liiH/unlis
of Sachs and Vialet extends from the inferior lip of the caUiarine
fissure (gyrus lingualis) lateralward to the convexity of the oc-
cipital lobe (gyi'i occipitales laterales). It is for the inferior lip
of the calcarine fissure what the fasciculus ocicipitalis transversus
cunei is for the superior lip of the calcariiu' fissure.
(5) The stratum propriuni cunei of Sachs consists of vertical
fibres extending from the superior lip of the calcarine fissure
vertically upward to radiate out into the cortex near the junction
of the medial with the lateral surface of the hemisphere.
In the frontal lobe fewer distinct bundles of short association
fibres have been nuide out. According to Dejerine, the fibrae
propria? of the frontal lobe are grouped around the corona radi-
ata, some extending transversely between the medial surface of
the frontal lobe and its orbital and lateral surfaces, others ex-
tending vertically and connecting the various gyri of the lobe
with one another. Still otlier bundles assume a sagittal direction,
especially those in front of the substantia perforata anterior.
Similar short association neurones have l)ee]i described in the
lobus temporalis as well as in the insula. Hut thus far our
knowledge of these bundles is too limited to nuike their detailed
consideration of profit in this place.
\
2. Those with Long Azones.
The association neurones possessing long axones have been
better studied, but the opinions of various investigators concern-
ing them are still markedly contradictory. Without entering into
the various polemics the following statements may be considered
to represent the consensus of opinion at present regarding these
bundles. Of the long association neurones the most imjwrtant
are (1) the cingulum, {'i) the fasciculus longitndimdis superior,
(3) the fasciculus unciiuitus (4), association bundles of the for-
nix, and (5) the taj)etum.
The cinyuhim * belongs, properly s})eaking, to the rhinen-
* This bundle was doscribcd under this name by liunlath. It was called
the fornix pcriphericus by Ariuild.
1 "
m
If
I
strK
VHV2
THE NERVOUS SYSTEM.
cephalon. The buiulle extends in a sagittal direetion close to the;
medial surface of the cerebral hemisj)here in the white mattoi" of
cm
Ciiiolk)
Fl(i. (ifiit. — KiiciisiMcdiiilis licniisiilin'rii siiiistri sliowiiit' tlic ciii^juhim. tlic fascii'
iilus liiii^itiiiliiialis iiitV riur. mikI (illicr IiuikIIcs of assiiciatioii liltrcs. (Al'ttr
,1. Dc.jcrini', Aiiiitiunii' ilcs ((litres lurvcnx, I'aris, IS!!,"), p. TrvJ. Fit;. !574.) (',
cimciis; ('iiiii'(i). fasciculus autcrior of tlu' ciuKuluiii ; C'ntiiUn. iiori/dulal m-
superior l)un(llc of the ciunuluni ; ('imti p ). jiosterior liuudle of tlie ciuKuluin ;
fill, sulcus ciujiuli ; cm', vertical portion of sulcus ciiifjuli ; Fhi. liawil inlernal
fasciculus of Huidacli ; /■'//', fasciculus loiinitudiiialis inferior; /•'».<, fiyriis
ftisiforniis : //( /, ). syrus liippocainpi : A', lissura calcarina : /,. f,'yrus cinf;nli ;
Lij. jiyrus liiiKualis ; /»/•'. medial surface of y;yrus I'rontalis siipcrioi' ; nt, lis-
sura collati iiilis ; I'nic, lobulus ])araeeiitralis ; juiir. siilcos in front of loliulus
paraceiitralis : /»). lissura iiaiieto-occipitalis : /')('. pra'cuneiis; so. sulcus snli-
(irliitalis of liroca ; sIrK. stratum calcarinuni ; Vs. K.vrns temporalis inferior;
Til. thalamus.
-50
the two main parts of the gyrus fornicatus, r.amcly, the gyrus
einguli and tlit^ gyrus lii{)[)0('iuniii. Dejerine describes it as tin
arcuate bundle which turns around the rostrum, genu, trun-
eus and splonium of the corpus cidlosum. At the isthmus gyri
fornicati it goes into the depth to enter the gyrus hippocampi,
through which it extends toward the uncus. The bundle, how-
ever, is not made up of tixones which extend the whole lenglii
of the cingulum, but of a great number of shorter axoncs
which are ever entering and leaving the bundle. According to
GROUPING AND CHAINING TOGETHER OP NEURONES. loO.S
Beevor,* it consists of three iiitlejuMidont fasoicnli — one anterior,
a second horizontal, and a third posterior (i^'ig. (idli). The ante-
rior bundle, he believes, connects the substantia perforata ante-
rior, and especially the region of the termination of the medial
olfactory stria, with the anterior extremity of the frontal lobe.
The horizontal fasciculus (extends between the medial lateral sur-
face of the frontal lobe and the gyrus cinguli, while the jtosterior
fasciculus situated chiefly in the gyrus hippocampi connects this
gyrus with the gyrus lingualis, gyrus fusiformis, and the cortex
of the polus temj)oralis. 'L'he cingulum in the developing brain
is shown in Fig. (J7().
"t
\[axf
m
••^^^A
rl .^'
/'
\
Xt
iMi!
\f'
ctu
ca
I ii
Fi(t. (>"0, — Marclii prcininition sliowiuf; dcgonpnitioii in dog's br.iin iiftiTflcstruc-
litiii of the lolms tVoiilalis. ' After Slnilsowski. taken fnini \V. von Hecliterew,
])ie lA'itiinKslialmeti iindeliirn und Kiiekeni..ark, Deutsch von K. WciiiIxT};.
II. Aufl., Lei|i/., ISdit. S. fidS, Fis;. r);!r>. ) (•((, eon'.niissiini anterior eereld'i <M)ii-
tainiiiK dejieinrated lilires, wliieli on tlie left sii'c ;;o over into tlie external
caiisule : ri\ cajisnia e.\t<'rna ; ci. cuiisula interna i 'arke<lly degenerated : fen,
cinKulnin ; tf, t'ornix Iohkiis on its way tlironfjii tke corpus eallosinn : /<c,
fasciculus siil)cilll()sus ; S';>, fornix fibres in the septum.
The fasciciilu ft loiifjitiu/innUs superior,} trianguhir in coronal
sections of the brain, extends as a curved bundle in a sagittal
* Boevor, C. E. On the Course of the Fibres of the Ciufjulum and the
Posterior Parts of the Corpus Ciillosuni mid Koriiix in the ^luiinospt Monkey.
Phil. Trans. i{oy. Soc. 1H91. I,„i,(i. (1H92). vol. elxxxii (H.). pp. i;{o-l!t)».
f Fasciculus areuatus of IJurdach.
!- -',,r
f I
'H '
l(trt4
TIIK NERVOUS SYSTEM.
direction, apparently between the frontiil lobe and the occipital
lobe (Fig. 071). The cell bodies of the neurones, which give rise
to the axones which constitute it, have not been well localized.
Fl(i. (171. — T.!itcnil surfacp of tlic left (■crcln-al licniisiilicn'. Tlic cdfrcs of tlic fis-
siini (•<Tcl)ri lateralis (Sylvii i have lircii iiinovcd. and llic iiyr'x |iiill(il apart
to show the iiisiiliir and rctroiiisnlai- region. Tlif t'asciciilus uiicinatiis, the
fasciculus Iciiinitudinidis superior, and llic fasciculus occipitalis vcrticalis arc
seen in trauspan'ucy. 'After .1. De.jerine. Auatoude dcs centres nerveux,
Paris. lKi)5. p. ~Tu. Kij;. Wi"!.) Arc, fasciculus lonjiitudinalis superior: /■',, /•',,
fjynis frontalis uiedius and fiyrus frontalis inferior: /i, sulcus frontalis infe-
rior : ./ii. sulci orbitales : l\[('). syrus fi-outalis inferior, jiars triangularis;
/•)(. fiyrus centralis anterior; /•'». iasciculus uncinatus; In, Ip, f-yri insuhc ;
ip. sulcus interjiarietalis ; mo. iii)). inf. sulcus circularis Kcili : ii,. (i^. jiyri oc-
ci))itales ; iin. sulcus occipitalis anterior of AVernicke ; iil\, nFt. 11F3. orliilal
jxirtion of fmntal ftyri ; OjiR. operculum, pars frontalis; Ojil'z, oiierciduni.
pars ]iarielalis : Or. fas<'iculus occipitalis v<rticalis ; I\. lolailus parietalissupe-
rior • /'v, loUulus i)arietalis inferior; I'n, syrus centralis |i<isterior ; I'c. tiyrus
aiifiularis : I'jin. (issura parieto-occipitalis : jinr. i>ortion of sulcus interparic-
talis behind the U|)per pari of tlu K,vrus ccntmlis ]ii(steri(]r ; /))(, suhlis pra-
ceutr 'lis , /', sulcus centralis Roland i ; Sin >. >'( /), anterior and vertical rannis,
anteri'ir horizoutalis, and iiinius anterior ascendens of tissura (ciehri lateralis
(Sylvii 1; 7'i, f;yrus temporalis superior ; '/'•■, ^ryrus tiinporalis medins ; ^, sul-
cus tciniKUiilis superior; I'. I', vertical rami of the sulcus temporalis supe-
rior; Tp. fiyri tenii)orales transvcrsi ; I'N, fo.ssii cerebri lateralis ^ Sylvii '.
It would appear that the axones of the bundle are of viiriablo
length, the majority of them not running through the whole
extent of the fasciculus, but, as with so many of the association
bundles, axones are ever entcing and leaving this fasciculus.
Among the axones in it are doubtless some extending between
GKOL'l'lXG AND CIlAIMXa TOOKTHEIl OP NErilONPX 1065
the gyrus ti'inponilis superior aixl the inferior frontal gyrus.
Tliis bundle on tlie left side is therefore, in iiU probability, of the
highest importance in connection with the functions of speech,
since in the gyrus temporalis superior is located the centre for
word memories, while in the gyrus frontalis inferior is situated
the centre for memories of the movements concerned in the ar-
ticulation of words (Uroca's centre). It is highly pn-bable that
axones run in both directions in the fasciculus longitudinalis
superior.
The ftisciruliis hiin/itialiiKf/ix inferior* is usually described
as extending between the lobus occi])italis and the lobus tempo-
ralis. It runs for a large part of its course close to the radiatio
occij)ito-thalamica (Jratioleti, but can, as a rule, be easily distin-
guished from the hitter (Fig. GI2). In it, too, in all probability,
are axones running in both directions; in the one case the cell
bodies of the neurones to which these axones belong are situated
in the occi[)ital lobe; in the other the cell bodies are situated in
the more anterior parts of the brain. The majority of the a.x-
ones, however, ap])ear to have an occipitofugal direction. It is
believed by the majority of investigators that a great many of
these axones terminate in the temporal lobe, especially in the gy-
rus temporalis superior, and the idea at once arises that tiiis bun-
dle is the one concerned in connecting the visual sense area of
the occiipital cortex with the auditory sense area of the temporal
cortex. These areas are undoubtedly connected, directly or in-
directly, by means of association neurones. That the fasciculus
longitudinalis inferior is, however, the bundle concerned is by no
means definitely proved. The ditViculty lies in the faet that in
the anterior part of its course it is extremely difficult to differen-
tiate fibres which belong to it fro!n other fibres which are adja-
cent to it or even mixed up with it — for example, the medullated
axones from tlie corpus geniculatum mediale and many of the
cortipetal axones from tlie nuclei of the thalamus. Flechsig ap-
parently denies a connection of the fasciculus longitudinalis in-
ferior with the temporal lobe; indeed, he inclines to the view
that much of this bundle consists of the medullated axones of
projection neurones. The majority of investigators, however,
insist upon the connection above descril)ed, and attribute many
\
* Stratum siigittale externum (Sachs); fai.sceau neriisitij (Charcot,
Ballet).
I
TV.':
1(h;<;
TIIK NKHVOUS SYSTKM.
of tlie visiuil disturban(!os iiccompiinyiiij; uphusic; lesions to inter-
ruption of the fibres of this path.
Fia. 672. — Vertical transvcrsi' scctiDii jiassiiij; tlii'ou<;li the |)(>sterii)r part i>r tlie
pra'C'uiieiis, tlii' lissiini parieto-occipitalis, tlie tissiira eal<'ariiia, etc. Metlnid of
Weifjert. (After ,1. Dejeriiie, .Viiatoiiiie des centres iierveii.x, 18!),'). p. 7tiH,
Fifi. I5S4. ) /•'/(', t'a.sciciilus loiiKitiuliiialis inferior; Fin. foniix nia.inr ; yVcS
fasciculus tninsversus cuiiei ; /''».s\ ;;.vrus fusiforinis ; in. sulcus occipitalis ; iii.
sulcus iuterparietalis ; A", (issura calcarina ; /,;/, n.vrus liuKualis; ()l, O3, <i,vri
occiititales ; oa, sulcus occipitalis; on', incisure of the sulcus occipitalis au-
terior of Wernicke; iit. sulcus collateralis ; I',, lohulus parietalis su))ericir;
/'(■. uyrus anjiularis ; y*f), tissura parieto-occi|)italis ; I'lC. pnecuueus ; RTh.
radiatio o( cipito-thalaniica tJratioleti ; Tap, Uipetuni ; I'oc, cornu posterius
ventriculi lateralis.
The fascinih(s inicinafii.s is a bundle of medullated axones
which extends between the uncus and the basal portions of the
frontal lobe. It would appear to be an association bundle belong-
ing to the rhinencephalon, connecting as it does the temporal
ft
GltoriMNCi AM) (.•IIAIN'IN(J T()(}KTIIKU OF XKIICONKS. [oOJ
flense area with the olfactory sense area in tlie base of tiie frontal
lobe. Autliors are, however, by no means agreed as to its exact
origin or as to its functions.
•Many of the axones of the /o/vz/.r are to be looked upon as
the medullated axones of long association neurones. Especially
is this true of the so-called olfactory bundle of the fornix which
connects tho hi])pocarupus with the substantia perforata anterior.
The fiipctioH, usually described as a part of the radiation of
the corpus callosum, is now believed by many to have nothing at
all to do with that body, but to represent a bundle of medullated
axones of long association neurones which connect the occipital
and frontal lobes with one another. Thus, in instances of con
genital absence of the corpus callosum it has been stated that
the tapetum has been found normally developed (Fig. CTIJ)
( Forel and Onufrowicz,* Kauf maun, f lIochhaus,J: Bruce.*) Forel
and others believed that the tapetum, therefore, represents a por-
tion of the fasciculus longitudinalis superior, but this is vigor-
ously opposed by Sachs and by Dejerine. Sachs tliinks that the
tapetum really belongs to the corpus callosum, and that, in cases
of congenital absence of the latter body, instead of passing
through from one hemisphere to the other, its fibres are trans-
formed into a sagittal bundle which does not leave the hemi-
sphere in which the fibres belong. Dejerine holds, on the con-
trary, that the tapetum belongs neither to the fasciculus lon-
gitudinalis superior nor to the corpus callosum, and that it is
not, as Sachs would have us believe, a displaced bundle of the
corpus callosum. He thinks that it is an independent sagittal
association bundle, differing from the fasciculus longitudinalis
superior in that it is located medial to the corona radiata form-
ing the roof of the lateral ventricle, while the fasciculus longitu-
dinalis superior is situated lateral from the corona radiata, its
most inferior libres being situated lateral from those of the ex-
^ I!
* Forol. A. Fall von Mangel des IJalkcns in cinem Idiotcnhirn. Tagn-
blatt il. 04. Vers, dentsch. Xaturf. u. Aerzte in Salzhnrg (1881).
f Kaufinann, E. I'^ebcr Mangel des IJalkens iin niensehliohen Gehirn.
Arch. f. psyohiat u. Nervcnkr.. Berl.. Hd. xviii (1887), S. 76!); Bd. xix (1888),
S. 229.
X Ilochhaus, H. Teber Ralkenniangel ini nienschliclicn Gehirn. Deutsehe
Ztschr. f. Nervenh., Leipz., Bil. iv (189;5-94), S. 79-9:5.
* Bruce, A. On a Case of Absence of the Corpus Callosum in the Human
Brain. Proc. B07. Soe., Kdinb. (1887-88), vol. xv (1889), pp. ;J21-;M1.
70
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IMAGE EVALUATrON
TEST TARGET (MT-3)
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ternal capsule. He j)'-ofers, therefore, to describe it as the fas-
liculiis (iccipi/a-fnmlnlis, identifying it with the bundle de-
scribed by Meynert as the radiation of tiie nucleus cuudatus and
T. OF .
V\ A
ds CA
OF(Top)
Fui
073. — Two vcrticiil transverse sectimis fron, m cerel)!-!!! Iieiuisi)liere, with
.■iKenesis of tlie corpus eallositni. i.M'tef Forel and Oinifniwic/,. from .1.
Dejeriiie's text-lxpok.i A. Scetioii iiassiiin lliroiijili piilvinar (if uptic tlial-
aiiiiis. H. Section alioiit '^(1 mm. I'artlier IiacU. .\. .l/r, al veils ; C.i, lii|)|)o-
eainpus (cornii amiminisi; Cij. fascia deiitata liipp<peanipi ; ri^c. corpus k<'"'-
I'lilatiim latenile; Cii-I. retroleuticiilar i)orlioii of caiisiila interna: tis,
(liverliculuin of tlie siil)iculuni : /vV, e(l<;e of itreliral cortex; /■'//. fasciculus
le.ijjiludinalis inferior; If. fryrus liippocampi ; li. tissura liippoeami>i ; /,i,
fjyrus cinuuli ; A'c. inicleus caudatus ; ,V<''. catnla nuclei caudati ; XL3,
pntiimen ; ()l<\ fasciculus occi pi to-frontal is of Forel and Onufrowicz ; at. fissura
coll ijcnilis ; /'»/. jiiilvinar ; 7';;. corpus fornicis : 7';//'. f'nd>ria liippocampi : IV.
ventriciilus lateralis ; I'v/i/i, coriiu inferiiis ventriculi lateralis. |{. C' ciineus;
7''m, <'alcar avis ; FH. fasciculus loiifiiliidinalis inferior ; A', tissura calcarina ;
(\fiTiii>), fasciculus occipito-frontalis of Fond and Onufrowic/,. forming the
tapeliim of tlie cornii jiosterius ; /)«, tissura jiarieto-occipilalis ; /i'77i. nnliatio
(iccipito-tlialaiiii<'a (iratioteti ; I'dc. cornii iiosleriiis ventriculi latenilis.
oiioui'iNc; AND ciiAiNiNc; T(>(ji-:tiiki{ of NRUWONKS. Kick
with the bundle described by Wernicke as the br.ndle from the
corpus ciillosum to tlie intenuil capsuUi (Fif,'. <m'4).* It is Deje-
rine's opinion tluit tlie bundle arises in the whole cortex of the
lobua frontalis. Behind, after passing through the tapetuin,
NC(T)
N'A %'
Fio. (i74. — F-'iisciculus occipitii-fivpiitiilis. tii'tiiii sciiiicircularis and fiisciculus imci-
iiatiis. Tlic ((irims < allnsiiiii and llic ciiiKuliiiii have Imtii ri'niovfd and tlic
conina radiata dissccli'd oi.t. Tlic iircparalidu sluiws tlic inferior wall of the
upper part (if tlw lateral ventricle and the ronf of the cnriiii posterins and
coriiii infcriiis. Partly sehcinatii'. (Alter, I. Dejeriiie, Anatnliiic des celilres
iicrvciix, Paris, isil."). p. ~f\;l. Via. ;iS\.) rj/c, cdrpiis t;eni(iilatinii latcrale ;
('(/(', corpus ;;eni<'iilaliiii; incdiale : fun. cdniiiiissiira anterior cerehri : I'n,
t'ascicnlus unciuatns : f.7e, nncleiis liahcniila' i .V.I. nncleiis aniyfidahe ; .V((,
nucleus anterior tlialaiiii : .NT, caput nuclei caudati : .\(''. caiida nuclei
caudati : An '/'). corims nuidei caudati: ()h\ fasciculus oi'cipito-frontalis ;
()I<\ Tup), part of fasciculus occipito-froiitalis foriiiinf; the tapetuin : /if'/,', toot
of corona radiata: I'lil, puKinar: .vi/i, tissura chorioidea : Tiik. coluuiiia
f'ornicis: Tli. thalaiuus; '/'/(» Tj ). part of thalamus iprojcctinfi; inio third ven-
tricle: /.sc(/ci. tuMiia seniicircularis. some (ilires of \vhi<'li are situated in tlie
lamina cornea : llh. tauiia thalanii : //. tractus opticus.
these fibres tire distributed to the hiteral surftice iiiul inferior
border of the lobus occipitalis. It is stated that the tapetuni
does not degenerate after experimental section of the corpus cal-
losuni, while it does degenerate after lesions of the cortex of the
frontal lobe (Muratow).
* Balketibilndel ziir inneren h'apsel (Wernickp).
It
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H^
i
CHAPTER LXVIIL
ASSOCIATION' NEURONES OF TIIK TKLENCKI'IIALON (CONTINUED).
Localization of association neurones in the cerebral cortex — Flechsij^'s asso-
ciation centres — The so-cnlled silent areas of the brain— Functions of
association centres — Functions of sense centres — The anterior asso-
ciation centre — The largo posterior association centre — Criticisms of
Flechsig's work — Studies of von Monakow, Sachs, von Kolliker, and
others,
3. Localization of Association Neurones in the Cerebral Cortex. Flechsig's
Doctrine of Association Centres.
The exact localization of the association neurones in the cere-
bral cortex is a topic attracting an ever-increasing amount of
attention. While it seems almost certain that there .ire associa-
tion neurones situated in every portion of the cortex, there is
much reason to believe that certain areas of the cortex consist
almost entirely of such association neurones. In this connection
the researches of Flechsig are worthy of especial recognition. It
is Flechsig's belief that the arciis of the cortex in which projec-
tion neurones play a part in the architecture are much more lim-
ited in extent than we have been accustomed to suppose.
Flechsig has traced by means of the embryological method
the various bundles of the axones of corticopetal projection neu-
rones to their terminal stations in the cortex, and has also traced
the course of the bundles of medullated axones of corticofugal
(motor) projection neurones from t^ieir origin in the cortex tct
their lower end stations, a ])rocess rendered comparatively easy
by the fact that the various bundles become medullated at differ-
ent ])eriods of antenatal and postntital development.
The best articles in regard to the quantitative relations of the
fibres of the cortex are those of Kaes.*
* Kaes, T. Beitriige zur Kenntniss des Reichthunis der Grosshirnrinde
des Menschen an markhaltigeii Nervenfasern. Arch. f. Psyeiiiat., Berl.,
Bd. XXV (1893). S. 695-758.— Feber den Faserreichthum der ii u. iii Meynert-
1070
-**
Hi
fiilOlTPING AND CUAINING TOGETHER OP NEUUONES. 1071
But even when all the sense areas and motor areas of the
cortex, extensive as tliey are, have become mcdullateil, only about
one third of the surface of tlie cerebrum has been involved. I'he
individual sense areas are isolated, not touching one another
directly. They are sej)arated by regions which have no direct
connection, at any rate at this stage of development, with the cen-
tres below or with the peri])liery of the body. It will have been
noticed that the sonuesthetic area, that portion of the cortex at
which bodily sensory impulses arrive, includes within it what has
usually been descril)ed as the motor zone of the cortex. In all
probability also from the visual, from the auditory, and from the
olfactory sense areas, corticofugal, probably motor, conductions
also go out.
As far as Flechsig has been able to nuike out, all or very
nearly all of the projection fibres of the cerebrum are accounted
for when the corticofugal and corticopetal paths of the differ-
ent sensory-iuotor areas, as outlined by him, are summed up.
But nearly two thirds of the whole of the cortex yet remains to
be accounted for. What is the significance, then, of the regions
which are not provided with projection fibres? The studies of
Flechsig have thrown these portions, whi(^h in large part corre-
spond to what we have been accustomed to call the " silent areas "
of the cerebral cortex, into bold relief. His anatomical investi-
gations, especially when their results are compared with the find-
ings of pathological anatomy in cases which have been carefully
studied clinically, indicate that these hitherto insutliciently ex-
plored regions possess functions of the greatest importance and
interest.*
If the limits described for the different sense areas be recalled
it will be seen that the regions lef over include in the frontal lobe
the anterior portions of the superior and nuddle frontal convolu-
tion, portions of the inferior frontal convolution, and the gyrus
scheii Sehiclit sowie iicber vcrgle.icliendc Mpssungpii der gesainmten Ilini-
rinde mid deren eiiizelner Schiehteu. Neurol. Ccntralbl., Loipz., Bd. xii
(1803), S. 11!)-122. — Teller die nuirklialtiiien Xervonfasorn in dor (irosshini-
rinde des Menscheii. Ihid., M. xiii (1894), S. 410-412.
* Thomas, speaking in this connection, says : " Flechsig's association cen-
tres are what have been called the silent areas of the brain; but we are
forced to believe that they are silent, not because^ they do not speak, but be-
cause we are too dull of understanding to hear what they say." Cf. Thomas,
n. IM., and Keen, W. W. A Successful Case of Removal of a Tiargo Urain
Tumor, etc. Am. J. M. Sc, Phila., n. s., vol. cxii (189G), pp. 503-522.
Ml
'M'
■'ii>
r''
l-,<.
i
Mjf,
Ml
1(»72
TIIK NKIlVors SYSTKM.
rectus; fiirtluM', tho ji^roatcr part of the island oi' li'cil, tlio supe-
rior and iiil'crior parietal lobules, the middle and inferior tem-
poral eonvolutioiis exclusive of the internal temporal pole, the
gyrus fusiforniis, gyrus lingualis, aiul the whole of the occipital
I'm. (i75. — \'i('\v dl' hit('i;il siiiracf iiC ri;;lit ccnlniil licmi.s|ili(ii'. slinwiiif; -.ciisc
cciilris mill ;issiifi;itiiiii iriil ri.s. (Al'icr 1'. I'lcilir-ij;. (Iiiiini iiiiil Sctlc. ||.
Aiitl., I,ci|i/... ISitli, Till', iv, l''!?;. T. ) Tlic iiiinc iIumIv iluttril ;iri;is slmw llif
rc^'iiiiis ill wliicli 111' majiirity ul' tiic stiisuiy priijirlidii iixmics tciiiiiiiiilc.
Till' lariit' |Hirlii)iis hctwct'ii llic (luttcil arciis itiu-cm'IiI tlicassiiciatioTi criitn's.
lobe not included in the visual sense .irea. In the diagram these
relations are shown very clearly (l''ig^. 0I.*» and Glti). The sense
areas are dotted, the regions in which the majority ol' the sensory
fibres terminate iieing closely studded with dots, while in between
the ditl'erent sense areas the largo undotteil regions correspond to
the |)ortions of the cortex entirely devoid of projection fibres, or
at most })rovided with extremely few of smdi lil)res. At the
periphery of each sense area is a marginal zone in whiidi pro-
jection fibres are less thickly distributed.
The white matter corresponding to all the cortical regions be-
tween the sense areas, with the exception, perhaps, of that beneatli
the angular gyrus, becomes medullated considerably later than
that of the sense centres, so that, even in children three months
old, the former are sharply distinguisliable from the latter by their
I
^
€■
GUOUI'ING AN!) CIIAIXINO T«»(iKTI!KIl OF N'KIIUOXKS. loj.'i
lIiosc
souse
sorv
IWCfll
nil to
.'s, t>r
the
pro-
is bc-
\i':Uli
than
OIllllS
thi'ir
poverty in niyoliii. Kk<'lisig finds, howovor, that inoduHatctl paths
^a-adually ^row ont from the sense centres into these non-rnedul-
lated regions. Further, between the individual gyri of the non-
nieduUated regions, bajids of association lil)res gradually ripen, con-
necting the individual gyri with others near them and also with gyri
at a distance, iiy means of the corpus callosuni tlie gyri in one
hemisphere arc connected with those of the opposite hemisphere.
Flechsig, on account of the marked predominance of association
systems in these areas, has designated them " association ctentres
of the cerebral cortex."* He docs not, as did Meynert, believe
Fio. Cui). — View of the iiiicli;il smiUcc nl' the lift ciTchnil ln'iiiisiilific. slmwiiis;
sense centres and associaliun cenlies. ( Alter P. I^'leelisi-j. ( ieliiin nnd Seele,
II. Antl., licip/., lS!l(i. Till', iv. Fi;;. S. ) /, e'liMus inaniniill:ire ; .', meiliau
section el' eliiasnia dplicinn ; .;. ccpniniissuni anterim cerelni : J. cidlicnlns
snperior; .■>, eiirpns callnsnni ; t!, lorni.x ; 7. septum p( lliiciduin : :. cnipus
pineale; 7/.S teninentiun : 7', basis pedniwuli.
that the individual sense centres are connected directly with one
another, but thinks that, on the contrary, they are connected
rather indirectly by means of the association centres. The lat-
* It is surprising to fuid how eldscly many <>f tlie views recently expressed
by Fleclisig accdnl with some ol' the duelrinus prouiulguted by llie Kngllsli
neurok^gist Hroadbcnt.
I. I
•::.
^ '' i
t.
'% 1
r
I I
i :
,i', 1
Jf
'«i 1
t'.'
ii
¥
[
.- ■ .
!''...■■ 1
i?n :,
■J074-
TIIK XEHVOUS SYSTKM.
H
Sji^
Mo
ter, receiving conduction librcs from luljuLont .?ense centres luul
from ;uljiu;ent us well as distant association cei^tres, furnish an
anatomical mechaiiisni which makes jwssible ^he w.*;"king up into
higher units of simple sense impressions and of combinations of
simple sense impressions of the same (piality and of dilTerent
qualities. Tlius Ficchsig denies tlie function ascribed by many
to the so-called fasciculus longitudinalis inferior which would
make it a system associating directly two sense centres with one
another. He thinks that, on the contrary, it has an entirely
diiferent signiticance, which, however, I shall not discuss at this
time.
The position of the individual areas of association probably
throws some light upon the functions which they subserve (Figs.
675 and (570). Thus the large region which Flechsig designates
as the posterior large association centre and which includes the
prjecuneus, all the parietal gyri except the posterior central gyrus,
part of the gyrus lingualis, the fusiform gyrus, and the middle
and inferior temporal gyri, as well as all portions of the occipital
gyri not concerned in the visual sense area, is situated between the
visual, the soniiwsthetic, and the auditory sense areas. Tiie island
of Heil is surrounded by the somt\3sthetic area, the auditory area,
and the olfactory area, and into it run bands of fibres from these
seJise areas, so that it, Flechsig thinks, is properly designated as
the middle association centre. The main portion of the frontal
lobe, Flechsig's anterior association centre, is very intimately con-
nected with the soma^sthetic area, and with the olfactory sense
area.*
While the anatomical evidence which Flechsig has hrought
forward would seem to be sufficient to indicate in general the
essential nature of the functions of the different regions of the
cortex described, there has been already collected a mass of clin-
ical and pathological data which, when reviewed in the light of
the newer anatomical knowledge, affords confirmatory proof of
his views. Lesions involving the sense centres are followed by a
train of symptons of an entirely different character from those
which accompany lesions of the association centres. This will
be clear if certain familiar examples be recalled. All the evi-
* As Flechsig renuirks, however, it is not probable that its function is
confined to t!.e association of olfactory impressions with sensations wliich
tell us alioiit the condition of our bodies, for the olfactory sense in man is
relatively little developed, while the frontal lobo is developed ad muximum.
Gltori'lNli AND CIIAINIXG TOOETHER OF XKUUONES.
1»»75
donee goes to show that tlio plicnonuMiu of shiir|i, <'h'iiii-oiit jicii-
siitions us they appear in I'onscioiisness liave tlieir origin in tlie
sense centres. As a resnlt of a lesion of a given sense centre this
shar})nes8 of sensation for the particuhir sense (|uality conci'med
disappears. If tlie visual area on hoth sides of the brain be de-
stroyed, the patient no longer sees, lie may oecasionally believe
that he still possesses visual sensation, but on closer exaiuitiation
it will be found that the picture in his consciousness is a ineniorv-
picture, not a perception. Patients sulTering from double-sided
destruction of the auditory sense area are absolutely deaf,* and
it is to bo imagined that if both soma'sthetic ureas were entirely
destroyed the individual wouM, if he continued to live at all, be
deprived of sensations informing him of the condition of his
body, of the skin, and of the visceru.f Injury to the central gvri
on the left side about their middle has been followed by loss of
power to recognize correctly the form of a given object when the
right hand alone has been nsed to feel it. Irritation of the pos-
terior central gyrus may lead an individual to believe tliat he
experiences movements of his thumb even when his eyes convince
him that it has not moved. Tumors pressing upon the olfactory
sense area have given rise to subje(!tive odors, while mental images
of colored figures aiul the like have occurred in individuals in
whom after death cysts involving the visual area of the occipital
lobe have been found. Irritative lesions of the auditory sense
area can give rise to noises and to other sound-images. Destruc-
tion of the sejise centre concerned witli the sensations of any
given sense quality is associated with the so-called perceptive
sensory disturbances.
The sense centres are concerned not only in the bringing into
consciousness of the individual elementary sense impressions,
but ttio distinction of the spatial and temporal relations of these
impressions, if Flechsig be right, is also to be attributed to the
., \
F- i
*Cf. a very imiiortiint rase desoribod hy Frii'dliiiKlcr, (\, ami V. Wcrnitke.
Kin Fall von Taiihlicil infoljje doppolscitiger Liision des Sfliliifolaiipens.
Fortschr. d. :\Ied.. I5d. i (lHS;i).
+ For evidence as to the paramount importance of the soma'sthetic area
for the development of a personality, the reader is referred to the thoroujjh
studies which were made of the brain of Lanra l{ridi,nnan. Cf. Donaldson,
11. II. Anatomical Observations on the Hrain and Several Sense Orj;aiis of
the Blind Deaf-Mule, Laura Dewey IJridgman. Am. J. Psyehul., vol. iii
(IKUO), pp. '.>'j;J-;542.
i
>: :• n
ir )
■:
iiiit I
/'!
1<»7«I
Till-; NKIiVol'S SYSTEM.
li '<:
I 1
(i'5,
activities of ilic cortical hciiso mijIutcs. 'I'iius " percoptivo word-
ileurnoss" has been shown todopeiul, in rigiit-liundod individuals,
upon disease of the left auditory sense area. Wlien words are
spoken the individual hears only confused noises ajid does not
understand them. Wernicke believed tiuit in such cases there is
a permanent loss of the memory i)ictures of the sounds of words.
This is denied by Flechsig, who holds that here we have to deal
rather with an incajjacuty of separating the sounds which follow
one another in the spoken words, of distinguishing tone intervals
correctly between syllabic.-; and words. The patient does not
perceive an orderly combination of sounds, but an undecipher-
able chaos of tones and noises. If in such cases we have to deal
with ])ure lesions of the auditory sense area the patients can
speak spontaneously a large number of words correi^tly, so that
the ordinary observer miglit scarcely notice any ilisturbance in
his speech, a fact which makes it seem likely that the memory
pictures of the sounds of words have been retained in spite of
the destruction of the auditory sense area. On the other hand,
if the ])eriphery of the auditory sense area bo destroyed, as in
Heubner's well-known case, aiul the auditory sense area itself
remain uninjured, the clinical picture is exactly reversed; the
patient in this transcortical sensory aphasia (in the sense of
Lichtbeim and Wernicke) can speak spontaiUM)Usly only very few
words (amiu'sic ai»hasia), or there exists a high degree of para-
phasia. The patient, however, can from the beginning repeat
correctly words which arc spoken before him, which is evidence
in favor of the view that he has heard the words correctly and
has retained the capacity for perceiving corri'ctly the intervals
between syllables and words. If, in spite of this, word -deafness
exists, the reason, perhaps, lies in the fact that the words cor-
rectly heard do not call forth by association into consciousness
the memory pictures which belong to them, and which help to
make up the sense (" ai)])erceptive word-deafness " of Herbart).
Of course, these forms are seldom met with pure, for in the
majority of cases the auditory sense area and its periphery are
diseased more or less together, and mixed forms are of no nse for
the decision of the cpiestion whether and in how far diseases of
the auditory sense area alone have disturbances of memory as a
result.
If the cortical form of " ])erceptive word-deafness " does not
depend on the loss of memory pictures of the sounds of words
r.UOUPINd AND CIIAIMNO TOCIKTliEU OF NKUIlONKS. |o
i i
iini-
H'ilt
nco
antl
Vills
ncss
■or-
sm-HS
) to
,rt).
the
are
10 for
es of
as a
not
ifords
;
it is liiglily i)rohiil)lc that it is a " sonsory atactic" (listiirhaiice —
tho toiiiporai arraiigciiiciit of the auditory sensations is laci\inj^.
If Flcchsig bo corrci't about this, tho essential basis for spatial
and temporal i)orceptions is to bo sought in the sense spheres.
Klechsig thinks that the tactile disturbance, described by
Wernicke, associated with disease of the soiuicsthetic area, is due
to loss of the capacity of nniling i)roperly tactile stimuli to a
mental image (that is to say, the spatial arrangement of the
single impressions is no longer i)0ssible). It is rather an atactic
disturbance of perce])ri(tn than, as Wernicke thinks, a defect of
menu)ry cajjatnty. It is cpiite analogous to the perceptive word-
deafness dependent upon lesion of the auditrtry sense area, it is
probable that the organic traces of the more extensive memory
pictures, built up of no matter what sense qualities, are associated
with the cells of the association centres which lie between the
sense centres.
Before passing to the descrijjtion of the functions of the as-
sociation centres, however, a few special points in connection
with the sense centres must be considered. With regard to tho
soniu'sthetic area it has long been known that disease of the
central jonvohuions is accoini)anied frc<piently with loss of the
kiiut'sthetic sen.sations, so that the mental images of position and
movement for the extremities and the region of the numth may
be absent or defective (Baslian). Along with these symptoms,
especially where the foci of disease are snudl, the cutaiu'ous sen-
sations suffer oidy as regards the tactile sense aiul its(,>xact locali-
zation. As a result of lesion of the arn) region there is an in-
capacity to recognize external objects by feeling their form. In-
deed, these disturbances of the stcreognostic sense seem to be
characteristic of c(>rtical lesions.
If the inferior frontal convolution be di.seased, tlie capacity
for calling up images of movements, or rather tho capacity to
feel the position of the organs which particijiate in speech, suffers,
so that sensory system Xo. 3, c(mnected with the inferior frontal
gyrus, is accordingly not ditferent in the sensation (|uality medi-
ated from the sensory paths of the central gyri, but simply in re-
gard to the region of the body whence the sensations come ; the
newborn infant, for ])urposes of self-])reservation, makes use far
earlier of his extremities, his lips and his tongue, than of his
trunk and s]ieech muscles, and this fact of experience agrees ex-
tremely well with the developmental finding that the sensory
a IV
'■: .1
i \
J * VW't ^
I
u
107S
Till-; NKKVors SYSTKM.
I'
'1
iiiid motor j)iitli.s of tlii" cxIrcMuitioa (lovelop carlior tlmn thoso for
tho trunk and tlio sjit'ciul or<,'ims of Hptrch ( Flcclisi},'). Certain
of tlio fibres of system No. 'Z Imvo Hppari'Utly to do with miiscie
sense, Imt our lvno\vI('(l<,'e is as yet insiinicieiit concerniii',' tliis
gnmi). 'riierc is a good deal of eviden-e, too, tiiat tlie sonia^stiict io
urea plays an important jtart in the coming into eonsciousness of
many of the hodily processes aeeomjtanying or constituting tho
emotions, and that tlicnce start out nuiiiy of the movements which
serve as tht; expression of tlie emotions, a i)oint of view wliich,
if conlirmed, is of intinito importance for psychiatry.
Let U8 now turn to the subject of tho functional activities of
tho association centres. We have seen before that from the
anatomical arrangement these areas apjjcar to f xist for tlic pur-
pose of uniting the activities of the various sense centres. C'lini-
cal and pathological evidence, too, is in favor of Flechsig's view
that they are concerned in the higher numifestations of the in-
tellect, in the processes of memory, recognition, judgment and
rellection. It is in disease of these areas that we see, above all,
disturbances of memory and of the associative j)rocesses. When
the posterior large Association centre, for example, is diseased,
the lesions are not accompanied with phenomeiui of perceptive
deafness, of j)erceptive blindness, or of perceptive tactile ana's-
thesia, providing the ailjoining sense centres remain unaffected.
But instead of these an entirely dilTerent group of clinical }/he-
nomena becomes manifest. Here we meet sometiines with the
conditions known as mind-blindness, mind-deafness, and the like;
with ajmixia or agnosia; sometimes there is weakening of the
power of visual imagination. 'J'here may be an iiica])acity to call
into consciousness melodies which the individual formerly knew
well, and in lesions of this area on the left side in certain portions,
sensory (optic) alexia, optic aphasia (amnesic color-blindness),
apperceptive (transcortical) word-deafness, verbal paraphasia, and
sensory amnesic aphasia (inca{)acity to call up the memories of
the sounds of words correspording to the mental images in con-
sciousness). The memory capacity may in such instances be af-
fected apparently in either or both of two ways — (1) by destruc-
tion of the association paths concerned in setting free given
mental images, and (2) by actual, permanent destruction of the
organic memory traces in the nerve cells. It wonld appear,
therefore, that the posterior large association centre is concerned
in the formation and collection of ideas concerning the external
GUOl'IMNHJ AND C'lIAIN'INd TO(JKTIIKU OV NKURONKS. lu7«J
world — tliiit !s, of iicliial kiiowlcd;^!' t'oiicfniiiig external objects,
of ('oiiil)iii!iti(<iis of sounds, imd lliu union of all these with onu
anotiicr. In these regions are stored up tiio elements of our
positive knowledge as well as the factors which come into play
in the exercise of the fantasy. It is here that preparati(jn is
made for speech which shall accord with the thonghts; in short,
this region more than any other in the cerebral <'ortex aj)pear8,
Flechsig believes, to be the site of the j)rocesses concerned in
what we ordinarily mean when we speak of the " intellect."
The anterior association centre — that is, the associaticm
centre of the frontal lobes — has manifold connections with the
soniiesthetiu area, and lience also with tlu; motor regions (!on-
cerned in condnet. So that here, in all probability, I-'ledisig
states, ia to be songlit the ajiatomioal mechanism by means of
which memory traces of all conscious bodily experiences, espe-
cially of acts of the will, are stored up. The study of the func-
tions of this region of the bruin is e.xtremely difticult, and as yet
only general statements can be made regarding them. It would
appear that the positive knowledge of the individual concerning
external ol)jects does not necessarily suiTer in diseases of this
portion, at least at tirst, although tlu^ !ii){)reciation of the value
of this knowledge and its relations to the individual himself may
be diminished. The man nuiy lose interest in the external world
as well as in himself and cease to participate personally in what
is going on about him. Indeed it is in the diseases atl'ectiiig this
area and the neighboring soma'sthetic area that most marked
alterations in the character of the individual are met with. Tlie
phenomena of attention, of reflection, and of inhibition are pos-
sibly especially connected with this frontal association centre.
Wundt has for some time believed that the "active ap])ercep-
tion " is to be localized in this region.
If Flechsig be correct in his views, it is evident that the
study of the normal functions of the association centres is of tlie
liighest importance and will in the future reJ)r(^sent pre-emi-
nently the task of psychology; while the phenomena which
result when the association centres are diseased will afford the
esj^ecial toi)ic of investigation for psychiatry. The study of
cases in the literature, more especially of general paresis, in
which careful pathological examinations have been made after
death, has already tlirown considerable light upon the function
of tliese areas. Of course, in the majority of cases of this disease
iH-
IdSd
THE NKHVOUS SYSTEM.
fl
ti
|[
tilt" lesions involve very dill'erent regions of the cortex at tlio
siune time. While in some instanees, however, the disease has
affected preferably the association '-entres alone without involv-
ing the sense centres, in a few cast s the frontal association cen-
tres, it is asserted, have been the o\w^ chiefly involved, and
in others the large posterior association centres have been the
ones nuiinly ad'ected.
Such material perm us of an analysis of the functions of the
individual areas. 'I'luis where the frontal lobes on both .sides of
the brain have been diseased the main symptoms rec<)gnizal)le
during life have been tiiose referable to an alteration or lo.ss of
ideas regarding the individual's personality and his relations to
what is taking place inside and outside his body — symptoms
which are highly suggestive when compared with the results of
(extirpation of the frontal lobes in higher apes, as carried out by
the Italian investigator Hianchi. The symptoms nuiy vary mucii
— probably according as the lesion is irritative or destructive in
its nature. Thus, in some instances, there is an over-appreciation
of self. Tlie patient's egotism is unbouiuled. All things ai'e
possil)le to him. lie is a niulti-millionaire, a genius, or a high
dignitary. In other cases he shows remarkable self-de|)reciation
and lack of confidence in his ])ersonal capacity. The speech
may for a long time remain unalfected ; bnt the ca))acity for
judgment as to what is right and what is wrong, what is beau-
tiful and what hateful, is often involved so that the individual
will exhibit in his conduct characteristics entirely incompatible
with what his friends knew of him earlier in his life. Such per-
sons lack self-command, even when uninllnenced Ijy violent emo-
tions; and when they are exposed to unusual stimulation, to
anger, or to sexual excitement, they lose all control of their (!on-
duct and are guilty of outrageous acts. Finally, if the disease
progress far enough, imbecility appears, and the individual p,ay
lose completely his ideas concerning his personality.
When the posterior large association centres have been maitily
affected the clinical picture is very different; in these cases it is
the knowledge of the external world rather than that of his body
and of his personality which is defective, just as one would ex-
pect from what has been said al)ove concerning the phenomena
of sensory aphasia nu't with in focal .softening of the cortex due
to v.iscular disease. In those individuals the ideas regarding tlic
personality may be tolerably clear ; they may have almost [)erfect
(JR()lIM.\(i AN'I) CIIAININCJ TUOKTllKU OF NKUliONKS. losl
8olf-j)i).ssessioii, but their friends notice, and they may tliemselves
be aware, that they are unable to re(!o<jnize objects seen ami felt
or to associate the elementary sensory impressions with the mem-
ories of experiences in their past lives. Such a ])atient will name
external objects wronjjjly, misunderstand their use, confuse per-
sons, and be mix (d uj) in his ideas of time and space. He is
unable to put into words the inniges which iloat in his con-
sciousness, and sulTers on the whole from a poverty of ideas.
Yet with all this ho may perhaps have a normal regard for him-
self and for his friends.
With combined diseases of the dilTerent association centres,
and especially with cond)iiuitions of disease of the sense centres
with disease of the association centres, the possible variations in
the clinical i)ictur(i become almost innumerable. For the analysis
of these symi)toms and their anatomical localization psychiatry
has been provided in these researches of Flechsig, should they
be contirmed, with a. most important aid.
It will bo of especial interest to study the functional diseases
of these difTorcnt areas, disturbances of a temjjorary nature which
can be ascribed to faulty nu^tabolism, in the dilTereiit areas de-
pendent u])on various factors such as imj)erfect nutrition, certain
intoxications, prolonged emotion, excessive mental and physi(;al
activity, and the like. The protean symptoms of neurasthenia
and hysteria often in individual cases bear a special stamp which
nuiy enable us in the future to suggest with sonu' probability the
portion of tlie brain maiidy responsible for their appearance.
liepresenting as they do ideas which fundanu'utally affect our
general concept of the structure and futu^tion of the brain, these
reseandies of Mechsig have, as might have been expected, not
]iasse(l unchallenged. After his address at Frankfurt a number
of leading neurologists and })sychiatrists iliscussed his tindings
and his views. It nuiy be interesting to consider briefly some of
the objections which have been offered to tlu'in.
A. number of invest'.gators are unwilling to grant that the
areas of the cortex to which [)rojection tibrcs are distributed are
as limited as Flechsig would have us believe. Thus, von .Mona-
kow asserts that projection fibres go to nearly all parts of the
cortex, though certaiidy some parts of it receive fewer by far
than others. Hitzig, too, grants that the num])er of projei'tioii
fibres going to the frontal lobe is very small. Von Mimakow
bases his objection upon the results of his studies of secondary
III
THE NERVOUS SYSTEM.
degenerations. Mo finds degenerations in the thalamus after
esions of certain of tlie regions falling witiiin the domains which
Flechsig calls association centres, lie believes, too, that motility
and sensation are represented in the cortex in ways fundament-
ally different from one another. His studies have convinced
him that the sense areas occupy much more extensive fields of
the cerebral surface than those indicated by Flechsig in his dia-
grams. Thus, the area for cutaneous and muscular sensations,
von Monakow thinks, extends far beyond the central gyri, since
;,o produce atrophy of the lemniscus and of the nucleus funiculi
gracilis and the nucleus funiculi cuneati of the opposite side,
destruction of the cortex (in both animals and man) of a far
greater extent than that which represents the " motor zone "
must have preceded. In answer to this Flechsig suggests (1)
that a totally insufTicient amount of material has been studied
by the secondary degeneration method to alford conclusive re-
sults ; and (2) that in many instances not sufficient attention has
been paid to the exact localization of the lesions ; that is to say,
not enough care has been taken to determine whether it has
been purely cortical or whether it has involved also the sub-
cortical white matter. He points out, for example, that lesions
of the })arietal cortex have been followed in a number of instances
by degenerations of projection fibres, but in all such instances he
believes the cortical nodule has affected l)undles of projection
fibres belonging to otlier parts of the cortex, but situated beneath
the area diseased. The results of experimental degenerations in
aninuds following extirpation of cortical zones can not properly
be directly api)lied to human beings, for in man there is a devel-
opment of the association centres not reached in the brain of any
other animal.
Another objection which very properly has been offered by
Sachs and others is this : That after a certain period of develop-
ment the medullation has become so diffuse in the cerebrum that
it would be imi)ossible to deny that later projection fibres passing
to the association centres may become medullated. It must be
granted that Flechsig can claim the limitation of sense centres,
as he defines them, only for a definite period of development. It
is certain, however, that at this period the primary sense centres
are sharply marked off from the rest of the cortex.
Von Kolliker's objection to designating the association centres
as intellectual centres is based upon his view that there is no
I
GROUPING AND CIIAINIXG TOGKTIIEIl OF NFiUHONKS. 1083
essential tlifferenoe between the pyramidal cells of the various
regions of the cortex. In the first place, however, as Fleclisig
points out, the time is not yet ripe for the building up of a psy-
chology based upon the histology of the cortical cells. One need
only refer to the attempt which has recently been made by lia-
mon y Cajal.* As a matter of fact, however, the sense centres
do dilTer very essentially, not only in the correlation of the
elements present in them, but al.so in the actual sliape and
position of tlie individual nerve cells. A skilled lustologist
who has studied sections from these regions can easily distin-
guish; a section from the middle jiart of tlie gyrus fornieatus
from one taken from the neighborhood of the calcarine tissure,
from the middle of one of the central gyri, or from the angular
gyrus.
Tiiese studies of Flechsig, taken togetiit.r with the researches
of Edinger, show that tlie anatomical mechanisms underlying the
mental processes in human beings as well as in aninuds are or-
ganically membered, and are only secondarily fused together into
an organic whole. Froni the study of the gradual development
of the individual organs of tlie bnun, as shown by ontogenetic
and phylogenetic investigations, we have the })roniise of a clear
and sharply defined picture of the various anatomical substrata
whicii in definite sequence are concerned in the gradually in-
creasing complexity of the organizing intelligence. While it is
probable tliat many of the theories which go far beyond actual
findings, which Flochsig has advanced regarding psychology, will,
with further knowledge, be entirely given up or much modified,!
still every one who reads his papers carefully will be ready to
grant that many of them are too well founded to be overthrown.
At any rate, he has supplied us with a mass of material and data
which must form the starting point of a whole series of subse-
quent investigations.
In deciding as to the relative value of the results of the recent
work of Flechsig, all will probably agrc-;' with His, of Leipzig,
who suggests that his most striking achievements have been (1)
the bringing of the anatomical proof of the existence of primary
* Kami'm y rjijal. S. Eiiiitro Tlyimtlicsoii ucbof doii utiatdinisclicii inc-
(.■hauismiis dcr Idconliildiiiij;. dcr Associatinn iind dcr Aiil'iiii'i'ksainkt'it.
Arch. f. Aiiat. u. Physiol.. Anat. Abth., Loipz. (IHi)-)). S. -.Wu'.
t Cf. .Taciilii. M. I', ("onsidcrations on Fleclisig's "Gohirn mid Soole." J.
Nerv. and Meiit. Dis., N. Y. (1897).
71
1(»84
THE NERVOUS SYSTEM.
sensory sense centres in the cerebral cortex and of the connection
of these centres with the nervous apparatus situated lower down ;
and (2) the determination of the successive medullation of the
fibres going to the single cortical areas and the exact periods of
such medullation.
I' *
ilia
9 I
m
1
INDEX OF AUTHORS.
Aoquisto. v., 289, 402.
Adamkiewicz. A., 132.
Agababow, A., 412, 271.
Algcri. (}., 1023.
Allbutt, ClifTonl, 341.
AUis, E. P., !)21.
Altinann, K., 145, ^ij^
Ambronn, II.. 8!>, 54.
Anaxiinander, 220.
Anderson, II. K., 44].
Andriezen, L., 29, 979, 6(J3.
Apathy, S., 38, 47, i)2, 23, M, 24 25
rp'' A'' J:'' ■^' ''''"'• -»'»<>•«''.'
62, 63,6,, 70, 73, 96, 13(i, 137, 138
07'
■3, 359,
140, 156, 265, 271, 2/2.
896.
Argutinsky. P., 888, 668.
Arndt, K.. 104, 655.
Arnold, .1., 667. 1044. 1058.
Arnstein, C, 33. 374, 277, 421, 530
Auerbaeh, L.. 78, 82, 191, 593, 602,
Aycrs, II., 499.
Azoulay. 206, 350, 666.
Baas, K., 832.
Babes, V., 25, 289.
Babinski, 413.
Bat'oii. Francis, 274,
Bner. K. E. von, 193, 790.
Raer. W. S.. 245, 246.
Baginski, R.. 504, 836, 852.
Baillargor, 821.
Baker. Prank. 10.
Balfour, R M., 179^ ^o].
Ballet. O., 151, 238, 289, 1065.
Baj-bacc.i,0.,.w,, 441, 442, 446,452,
^ 5^9 '"' ^''"''"^'' ^'•' ^^' '*=^' '^^'253,
Hartholow, R., 1002.
Iksilewski, A., 960, 614, 615, 967,
•MO.
Bastian, 442, 1077.
Batten, F. E., 418.
Raumgarten, P., 786, 792
Beale, 102.
Beard, J., 179,200.
Reehterew. W. von, 28, 13, 82 46
268, 270, 319. 424, 427. 428 '429
430, 473, 501, 5u4, 505, 509, 511 523*
34{), 529. 565, 569, 570, 382 '577'
386,592, 605,608, 609, 401 ' 612*
402, 613, 614, 403, 4oi, 618 63o'
f 2, 635. 424, 655, 658, 431 659
432, 664, 684, 688, 446, 692, 694;
^00. -05. 456, 708, 715, 716, 805
««^^^~oY'^^'^'^'^^«'«43,852,864;
865,872.888,954,609,956,957 958
»60;«66,614,615,967.'968,'9 4
«5J0. 1020,1047,1063,670.
Rt'ck. A.. 289.
Rfcker, 96, 137.
Beevor, C. E.. 346. 995, 996 632
1000, 1001, ,003. 635 636 63^'
1007,1008,639,1063. '
Bell. Sir Charles, 3, 897.
Bellonci. G.. 831.
Benirnelen, J. F. van. 201
Bi'rard, 229.
1085
mB'
f
ii::ii / -I
1()8<5
THE NKRVOUS SYSTP]*!.
u
Bcrdcz, 441.
Herger, II., 94.
Hergiimnn, G. IT., 840.
Berkley, II. L., 10, 11, 29, 37, 88, 71,
76, 3«, 230, 153, 154, 285, 288,
:W 1.402, 411. 418, 8!>2.
HernluniiKM-, S., 2;i5, 911, 942, 045,
94G. 050.
Bert. 1'., 000.
Bethe. A., 34, 36, 37, 38, 46, 96, 137,
138, 130, 145, 153, 2(55. 271. 272, 1«2.
273, 316, 213. 305, 366, 368, 219, 474.
Bettmann, M., 120.
Betz, 108, 112, 135, 078.
Biniielii, 1080.
Biedcrmann, \V., SO, 060, 065, 613,
OOC). 068, 973
Biedl. .\., 231, 235.060, 965, fil3, 066.
968. 073.
Bielsehowsky. .M., 705. 717.
Biesiadecki. A. von, 788.
Bignami. A.. 590.
Bind.-<cheidler, 33.
BinswangiT, O., 04.
Birge, K. A., 5.
Bli.x, M., 330.
Blninonau. 565. 568. 576, 577, 580, 581 .
Bocdekcr, 200.
Boelnn, A. A., 3«2.
Bogroff. 830.
Boik.L.. 105, l:n. 132, 133, 134. 135.
205, 208, 13(». 200. 137, 138, 211,
139, 140. 141, 142.
Boll. 7. 104.
Bolton, T. L.. 531.
Bonnet. K.. 225, 226, 374.
Born. G.. 318, 701.
Bouchard. C. 1012.
Bouin, 37.
Boyce, K.. 070. 971, 617, 072, 618,
619.
Brasch. F., 289.
Brauer. L., 287.
Bregmaiin. E.. 231. 232, 147, 148,
306. 522.
Breginann. L. K.. 030.
Brieger. L.. 241. 450.
Brissaud. E., 201.
Broadiient, 1073.
Broea, P., 748, 740, 750, 751, 755, 762,
1065.
Briico, A., 456, 458, 461, 565, 560, 587,
60H, 600, 406, 637, 717, 459, 033^
598. 1007.
Brunii, A. vor- 352, 5.32.
Bruns, L., 33u. 442, 450, 53C, .594.
Bnix, 651.
Buck. A. ]]., 783.
Buhlor. A.. 148.
Biinini. 700, S36.
Bunting, ('. II., 207.
Burdach, K. P., 24, 436, 4...' ■i<]8, 565,
570, 576. 667, 673, 674, 680, 681, 705,
7H(i, 000. 1061, 1063.
Bu.scli, ('., 601.
Butschli, G., 138, 141, 145, 147, 154.
("almnnes, C, 289.
Cadiat, ().. 194.
Cajal. See Hanion y Gajul.
Callcja. ('.. 262. 761,487, 488.
t'anipacci, (J., 300.
Carnoy, .7. ii.. 154.
Cattani, 246.
C'avazzani. E., 358.
(Vni, ('., 228.
Chantemesse, 301, 302.
riiarcot. .T. ^\.. 428, 050. 975, 093,
1005, 1012, 1014, 1065.
Chiari. 056.
Chii'-ugi, 028.
Gill, -zi, L., 200.
Chipault, 201.
riiristomanos, 413.
Giaccio, (i. V., 405, 2(>4. 265. 266,
267. 410, 411.
(Magiinski. A.. (110.
Glarke. II., 078.
("larkc. .1. liockhart. 172, 403, 474,
504. 576. 581, 851, 913.
Goen, 24(».
Golmheim. J., 214, 302.
Golc. 921.
Golent)ninder, 911.
Gollins, J., 905. 010.
Corning, 019, 589. 591.
}■ .: :-t
INDEX OF AUTHORS.
1087
Corti, 112. r)4r).54«. HUG. 8:J0.
Cox, VV. FI.. 10.
("rumor. A., 21»0. 505, 51S, 569, 651,
664, 716, mo.
('nivt>illiiiT. 2'i'X
C'liccuti, (i., 381, 111.
("iishing, Harvey VV., 339.
t'zokor, 368.
D'Abundo. 402.
Dana, ('. L.. 339. 340, 341, 107. lt)S.
l))irksclic\vilsi-li, I.. (»., 'J31, 300, ."iOD.
614, 618. 716, 719, 721. 724, 725.
K05. 831.917. 944. 945.
Darwin, t'liarlcs, 76.
Daviilc.ff, M. v(in. ;l(»2.
Dawson, I*. M.. 245.
Haxenbcrgcr. II., 450, 452,
Deiin, .lolin, 504, 851.
Dc-avcr, .1. 1$., 1002.
Di'cn, Van. 897.
Dees, O.. 623.
Di'liio, 288.
Di'lilcr. 148.
Deiters, O. F. C, 4, 1, 5, 12, 102, 122,
131. .504, 505. ■07, 508, 509. 511. 512,
.523, 508. 575. 030. 631, 632, 63(1. 637,
638. 849. 960, 964. 965. 96(). 967. 968.
Dojerint'. .(.. 289, 290, 442, Ar>x. 655,
668, 674, 44ri, 705, 707, 71fl, 731,
732. 511, «38. 1044. 1046, 1047,
10.59, ({(;S. 1061. 1062. HM). 1062.
(J71,«72, 1067,074, 106!*, 673.
Dejerinc, Mnie. .!., 70,5, 707, 717, 731,
732.
Deiuoor, L.. 418.
DeQuervain, Fritz, 111.290.
Dcrfuin. F. X.. 832.
De Will. Lyilia, 417, 275. 419. 270.
27S.
DextiT. Franklin, 175.
Dii-kinson, 229.
Diolitnii. 220.
Dij^se, ,T., 18 i, ,526.
Dixon. A. F.. ,525.
Dniitrijewski, P., 2a(J, 382.
Do-jit'l. A. S.. 34. 36. 37, 105, 141, 145.
184, 115, 18.5, 11«. 262, 365. 21(5.
21 7. 218. 37(1. 240. 241. 386, 243,
244, 388, 390. 393. 252, 394. 253,
400. 261>. 2<)0. 2({1, 2(J2, 418, 421.
.534. .540, 897.
DoKicl, .1., 418.
Dohrn. A., 170. 19.5.201.
DoniiUlson, U. 11.. 42. 80, 251, 275,
.531. 1075.
Donilers, F, (' ,835.
Driescli, 221.
I»ii lU.is-Keyniond. E.. 2.52.
I)iil:.nr. 4,50. 457, 4.58.
Duret, 1014.
Diitil. A.. 151.238, 290.
Duval, .M., 100. 942, 947.
Fhbinfiliansi. 835.
Kberslaller, 754.
Kberth, 365.
Iv'khanlt. ('.. 330.
Kdinger. L., 10, 29, 38, 44, 254, 316,
463, 523, 565, 569, 590, 598, 599,
664. 715. 748. 764, 766. 4S9, 775,
500. 804. 902, 903, 933, 942, 944,
945, 1056, 1058.
{•'luvnberg. 3.
Klirlicli, l'.,31, 32, 33, 36, 37. 47. 67,
101, 127, 128, 186, 241, 365, 394,
402.411.4,59,530.897.
Fiscnlolir. 413.
Fisler, P.. 19.5, 18(;, 187.
Kinniort, 3.
Fngehnann. 142, 157, 359.
Ei-b, 244, 899.
Frlanger. ,1., 1.50, 237, 295. 17(), 308,
911.
Eve, F. C, 278.
Fwart,921.
Kwing, ,)., 289.
Exner. S.. 252.
Firricr. D.. 565. 570. 572. 383. 573,
3S4. 385, 580, 304, 655, 708. 717,
823, 899, 900, 9(i4, 973, 994, 995, 996.
997. 1000. 1028. 1047, 1055.
Fieschi, D., 246.
Fisclu-r. A.. 131, 141.
Fish, P. A., 43.
I
1088
TIIK NKKVOUS SYSTEM.
Platan, K., 2;J1, 2;{5, 14», 277, 280,
285,286,28)). 174, 1 7S, HOI, 17«,
302, ISO, I HI, l.s'i, :{()(;. ;{08, :no,
450. 458, i)ll, !)14, i)5;J, lOO'J. (}40.
Fh'disig. P.. 25. 44, 87, 8!), })2, 244.
25(5, 2(i5, :iU\, 424, 425, •_»«(), 427,
428, 429. '_»S1, 2M2, 4;{0, 4;J0. 452,
45;j. 458. 4(11, 4(i:i, 47:5. 504, 505, 50!),
50:{, 5(i8, 575, 577, 581, 58;{, 389.
391 , 5!)2. 5!);{. 598, 605, 608, 60!),
614, 647. 657, 667, 681. 684, 685, 686,
688, (18!). 607. 6!)!», 700, 702, 70:), 704,
705, 707. 714. 715, 721. 7:iO. 7;n, Vi'.i,
T-i4, 4(W, 7.'}6. 4(J7, 4({H, 7;i8, 75;3,
75!). 772. 806. 816. .jL'o, 822, 823, f^O,
836. 837. 843, 852, 875. 876, SiJl,
878, 963, 974, !)76, !)80, «25, 986,
987, «2«. ($27, (;2K, «2«. 991. «30,
992. (531, 993, 1010, 1020. 1021,
1040, 1045, 1047, 1065. 1070, 1071,
«7r>. 1073. ({7«, 1074, 1075, 1076,
1077, 1078, 1079, 1081, 1082, 1083.
Fleming, H. A.. 232.
Plemmiug, W., 104, 105, «3, 113, 135,
141, 145, 154. 156. 281.
Flesch, M., 123.
Flexiier, Simon. 247, 297.
Fcerster, 826, 828.
Forel, A., 9. 15. 17. 18, 20, 22, 26, 231,
651, 653, 655. 657. 668. 435. 670.
43«, 671, 672, 437, 673, 43H, 674,
675, 682. 684, 685, 686, 692, 704, 727,
730, 731, 732, 772. 798. 805. 812, 836,
841, 873. 971, 1067, 073, 1067.
Forgue, K., 900.
P'orster. Lanra. 412, 413, 414.
Foster, M., 86. 554. 963, 965.
Fraenkel, 413.
Franck, F.. !)83, 1003, 1022.
Francke, C, 42.
Francotte, 591.
Frankl-Hochwart, 747.
Franklin. Mvs. Cliristine Ijadd, 835.
Prenil, S., 569. 716.
Fioy, M. von, 253, 255, 330, 372, 392.
Fricillaendv". ('., 229, 1075.
Friedinann, }l.., 290.
Fritsch, (J., 994.
Kroinnmnn, 102, 154.
Fn.ri.'i). 350, 927.
Kliil Hinder. M.. 195, 920.
Fiirstncr, 983.
Fiisari. 962.
(iad, .1.. 235, 2ii8, 100!), «4(K
(JaliM.Iti, (J.. 141.
(ianscr. S.. 668, 761, 767, 768, 784, 788,
.'>0(5, 798. 807.
(iardincr. 7.
(lawkell. 888.
(}(>l)erg. A.. 370. 223, 224.
(iel.iniid. P., 716.
(iogonbanr. 1!)5, !•!!». 921.
(iciiuclitcn. .\. van. 9, 't, l.'i. 2!t. 45,
31. 34. 4S. :,.-». 142, 144, 171. I82!
110. 114. 1H4. 254. 260. 261. 262.
l.'iS. 266. 270, 2!)!). 30!). 194. 19.'),
19«, 2i:». 365, 374, 375, 292, 465!
467. 303. 304. 49!). lOO. 514. 342.
523. 530. 546, 606, 6 IS, 650, 673, 675,
454, 721, 725, 775, 803, 826. .i3o!
832. SH5. !tl4. !t2(i. 932, 599, !)42,
!)45. (J05, <{24. 985.
Gennari, 821. 1058.
(Jorhifh, J. von, 5, 2, 6, 7. 13, 42, 60,
463, 884.
(iiose, 450.
(iicson. Ira van. 108. 110. 142. 1.55,
239, 522.
(iilbert, 229.
(iildcr.slcL've, Basil L., 40, 667.
Oocppert, 38.
(ioi'tlic, .lohann Wolfgang von, 221.
Goldsclu'idcr, A.. 251, 253, 255, 277,
280, 285, 286. 28!). 1 7S. 301. I79!
302. 1S(K ISI. 1S2, 307, 308, 3()!».
330.
({ojgi, (".. 9. 10. 11. 12. 13. 14. 15, 17,
18, 21, 22, 25. 26. 28. 29, 3(i. 37, 42,
47, 48. 50, 63. 64. (i7. 68, 75. 76, 78.
79. 80. 81. 82. 84. 90. !)3. !)4. !)(!. !)8.
101. 115. 13!). 140, 7.S, 1.50, S5, 152.
153. 172. 184. 239, 240, 257, 258, 25!).
261. 265. 270, 317, 365, :i70, 374.
376. 378, .•!86. 392. 394. 396. 402,
2(53, 405, 409, 410, 411, 424, 430,
IXr)R\' OF AUTflOFfS.
457, 450. m, m, 4fi5, 4«(( 407
40H.47O.47;(.5ll,r,|H.5^>0,5;]O.5:{|'
•»;K 5H(). «;{a, (i;i,i. (j;{7, «r,!<, «(i4 m:
"H7H.,7:>5.7;W.7«H.775,7H4:7i*r
hoo.ho;j,si2,hi';{,h;w.n40,84;}h5->'
»;;^ !.47,»5.>,!«i,s. !,:,.!,:«, »;„,,,H„;
io;i;i, io;j4. io;m, 105;]
Ooll 24,424,425, 427, 428, 489, 430.
4S.i, 435, 4:)«l, 439, 504, 705.
(roller. A., 835.
Goltz, 705.
Ooinlmull, A., 442, 450. 452, 453 454
450.458,401.
Ootch, K, 274.
(iowcrs, VV. U.. 45. 589, 590 rm V)->
593,594, 598, 599, 00 1, 002. (i04 (!(»5
649, 740, 780, 900, 972, 973, 'lo;j7'
1039. '
<ii-ar. A., 1.55,
(iraiidry, M., 309, 370, 222.
<im.sliey. II., 231, 785. ol 4.*
(iratiolol. 007, 814, 810, 823,
(Jreiwe, ,1., 717.
(Jrigoricir, 229.
Onietziii'i-, 1»., 790, 792.
C.riinbauin, A. S., 418.
Cniarnicri, G., 5f)0.
(iniUlen, M. vo.i, 18. 44. 100. 231 300
308, 054, 097. 755. 767. 772, 777 784'
7B5, 780. 787, 504, .-,().-,, 790 ' 791 '
793, 790, 798, 804. 805, 514 8O7'
831,899,942.945,950,1022 ' '
Ouddeii, H., ,'-,]7.
10SJ»
HabcrlaiuK, 307.
Haookel. 05.
'I'lllcr, H., 7, 17, 38, 04.
Talliburtoii, W. I)., 132.
Flallopeaii. 983.
Haiiiakcr, J. 1., 149,
Hamilton, Alice, 500, 781.
Hamilton. I). J., ]().^,5.
Ilummarherg,('.,822,528,878, 5«;{
978, 979. ({23. '
Hammoml. G., <)05, 583.
Ilampe, 244.
Ha.uiover, 787, 805, 807.
M arris. I|. F.. i;{o.
Ilfwriso,,. u. ,,. ,„{ ,,,,
919.
Hassc, C, ;{28, 201.
Hayem. 229.
"ayez. F.. 051.
Head. 11.. 198.;j;{j), 340, 341, IJ)}). JOO
340. ' '
Heard. ,1. I)., Uy^2.
H<'iderdmiii. .M.. 281,
"•''•'• H., 4.38, 47, 48. 18, |» '»o 50
21. 22,07,4}*, 85.54. 8!,. .,.4 '.-,«'
K'9. 111. 128. 129. 130, 75, 13 1" 7«'
-7, 132, 133,134. 140.141, 143 I44'
•HI. 82, 145, 147. 83, ,S(j, ,r,:i. ,.^V
!•)»!, 218, 235, 241, 20.5. 281. 319 48o'
4M4. 32«. 327. ^m, r,no, m^ :)i4,
•'{«8, 3(J{). .5,5.5, 577. .580. (ioj) <5ir,'
«1H,032. 4! 8, 037, 422. O.55" 075*
725. 772. 4»3, 4{»4, 804. 8 j 2, 832 8.'o'
«37, 535. 839, ,S42. 843. W 8.-,i"
H53, 854, 85.5. 857. 54(1. 547 80"'
.}.}l.«04.8(i0.554, 808, 555,551;,'
•>.>., 872, 570, 947. «0(;. 950 !)0y
«1«. 972. •
H''lmlioliz. jr.. .3. 7«7, a3.j.
Hclwe^r, 9.54, 957.95s
H^de,. 1^:^340. 372: 373. 374. 375.
•j^<>. .J<7. 787, 790. 50{). 524. 89(i,
Henri, 330.
H.>ns,.|,en, .S. F.. 717, 793, 820, 827
828, 832. •
Hensen, V.. 949.
Hcraclitus. 220.
Herbart. 1070.
Heibst. G.. 221. 393.
Hciiii-r, E.. 83.5.
Hermaiiii. 347.
Herreidieiser. 793.
H.Tri,.k, C. J., .5, 44, 7^1 ,)o, ^32
-.{)2. 924, 1050. ' •
Hvirick, ('. L., KKTie
Hen-iiiirliafii. W. P.. 332.
Heiter, 241.
Hertwig, O.. 0.5, 1.54, 125.
Hess, P.. 289.
Heubiier, U)7().
m
I
SI r>
i I i
1()S)U
TIIK NKIfVoUS SYSTEM.
ncwcisoii. .i,,iiii. .'tos.itoo. :no. .*ti i.
.'{ I '.'. :i 1 11 :i 1 1, .{ I ;,. .{ i «. .{ i ; .{ i h.
a I U. :{'_'o. :{•.» 1 . :{i'2, :{•_»:{, ;{24. ;{•_»«.
a 7s. .{SO. :{s I , UK,, 1 1 4. u :>. 4 1 IJ.
I/qiiifiil<>. -lOO.
Jackson. ■!. lliiKliliiiKS OH^. Omt.
.liMohi. M. I'.. I(»h:{.
■t20.4L»«. 427,4:{0, 447. 44.S, 441», | .lacdl.M.lm. L.. 2H(), 7H((.
4.-.1!. 4r>:{. 4«5I. 4(J1V 4«:{. 5a7. .'.:»M, I .lacciiics. I'.. 403, 411).
Mil .'».V_', :»S».'». .-»«MJ. .-,«»7, r.(M. «0'-'. Iiikol.. ('.. 70.1
<>o:t.<i rj.
II
.1. \-\.\lH.
I'yillilllr-
Hill. A.. 11.77.
Mis. W.. :!. i), 1,-,. Hi. 17. ','0,22. 2«. 44,
70,04. i;t(;. i.-.o, ,s5>. itiit. jh). 1M,{)2.
HM. »:i. »4. Hi.-). UiO, {>.'i. 1(17. IC.H.
1(10. 17(1. 171. US, 172. KM). 102,
!():{. 104. 10.-», 177. 170. 180, 181,
1h:i, ll;{. li»((, l<)4, If),-,, 212. 214.
22.V 2(;(i, 27;!. ;il7, L»OL», L'0:{. 424.
aOT. ."lOl. ,-,i;
i;i7. 748. 740. 7.'5(),
7.TI. 7."».j, 774. 4!)(i. 7M4. .••.S7. Kw:!.
Mis. \V.,,lr., 1 1 7, l'_».% 101, .-{.W, Ml,
r.l4.
IFit/ijr. H.. 094. 1081.
Iloili. A.. 244. 200, 201. 202. 20;5. ;{()«.
Hcclic. A.. 4.')0. '-'{)({. 4r,;i. 4.')4, "it)?,
'_»!)S. 4r,r.. iM)!). 4"i7. 4."i8. 4(i2. JlOl.
;J02, :{!)s, .-,os, (i()2. oi.'). <ii7. om.-).
1016. 1017, «4.'{. 1020. «44. 1022,
Tlociiliaiis, II.. l(m7.
1I(
('. !•'.. 27r.. 1(J:{. 277. 1(J4.
n»:», i««. 270.
IT
oeii.
A. (i.. II. 120. J)«. V2i
Hocscl. 44. (144. ()07. «'•"•, 702, 708, 704,
707. 714. 717, 7:$1.
llolTmiinii. .1.. 717.
llnfricht.T. I<:.. 442.
Holm. 11.. ()21.40S.
II(
■II. 40.
Iloiiieii. K. A.. 237, 229, 230.
lloiiofjKLT, 727. 7:52.
Ilorsjcy. v., 274. 4ir,, 441. 004, 00.",.
00(1. Hii'l. 007. CttMl. 000. (J:J4. 10(t(».
1001. «3.'». 1002. 1003. (»»«, ({.'{7.
1007. lOOS. (5;{!). 1024. 1047.
Howell. \V. H., 227. 245.
Uiibcr. G. Carl. 36. ««. 114, 237, 245,
4 Hi. 417. 275. 410, 27(5. 278, 802.
Hun. H., 522.
Huxley, T. IT., 65, 195, 931.
.Iiikovciiko. \',
ri8.
>n\
.Idlinslon. .1. M., 931.
.losrph. 2."i8.
.Icwctl, M.. 220,
.luliuslturgtT, 200.
Ka.'s. 'I'., 1070.
KalilcT. <).. 439. 048.
Kaiser, (>.. HH4. 88.',, 00,'i. 57H.
r>,SO. .'»S1, 5S2. 014.
Kallius, K., 360, 368, 304, 400, 897.
Kain. 1046.
Kanisin. I'.. 424, 43(».
Kiistner, S., 201.
Kaiiriiiann. Iv, 1067.
K 'en, \V. W., 1002, 1071,
Kellerniiiiiii, M.. 786.
Kell.v. A. (>. .1.. 43.
Keiu|>iier, \V.. 301.
Kerseliiier. I>., 412. 413,415.
Key. I-;. A. II.. 104.
Kiii,i:sl)ur.v. M. F.. 021.
KliniofT. i. A.. (iO.-,.
Knapii. I'. ('..34(i, 201, 349.
Kiiies, 8;j'.\
Knoblauch, 983.
Kocher. T.. 330. 201.
Kolk. Seliroiler van <ler. 851.
Kulliker. A. von. 3, .5, 9. 4. (>, 11, 26,
28. 20. 1 4. 30. 40. ;{.'». 7M. 70. 40. 4(5.
81. .'lO. .'il, .V2. 0(». 02. .'>(5. 04. 100.
102, 143, 148, 155, 107, 10(5. 111.
2.")6. 2.18, 2.10. 261, 266, 270, 462,
463. 465. 467. 468, 474, 475, 477,
480. .501. 511, 514, 518, 523, :{.>1,
5.54. 577. 5H1. 606. 618. 621, 632. C3(J.
637, 641, 655, <i68. 674. 675. 676.
439, 679, 735, 755. 756. 478. 4 7 J).
4K0. 4S1. 4S2. 4S.'{. 4S4, 4S5, 4S(5.
, 768, 4!)0, 770, 775, 4«7,
766, 7
777, 779, 783, 790, 703, 800, 801,
L
INI)1<:\ OF Al TIIOKs.
513. NOT. HOH, «00. r,lM, 822. H;{2
«ir, H41. Hi;{. r»:i«, Hr,i', ^o' h.w'
W!). H02. Hm, r,r,». wih, 895.' ii2H'
i'42, !)4r,. (J07, «os. iKiH. «2I «7i/
i(»:m. 1082. •
K"llimmii, .1., NS. Kir,. »}». n; j^
MJ>. I2;{, I2«, 127. I2}». 202 ;{07
■•Wl. .VH7. !»l!(, .>S}), .-,{)0, .-,j,i.
Korolow, |».. 2;{0. ;{81.
Koslicwnikow. 2.(1.
Ko.sscI, A.. 142.
Knicppliii. !•;., 244.
Kniusp, i{., .500.
Krauso W.. 2W, 2m, m, m, m,
'«M. 412, o4 1. 784,78.1, 8!ir,,8!»!).
Kncs. ,1. von. 8;^,.
Kroiniijpr, 04.
KroiicnlHTrr^ f^{)~
K'i'oiillial. 1(»,-,.
K'iluw, W.. 400. 412, 413. 80.-5, -.74
i'o, ■>«.>. .»7<».
K'upffer. (;. von, 03, i;J6, Kir,, 910.
Kusii'k, 083.
lOUl
lifihonlo, ,1. \'., 042, 947.
Ijaiiilierl, .M., 278.
Ijaiicisi, 704.
Lniij,'(', 442.
I'aslcd. K. I-;., 288.
Laura, .184.
liavdowsky, 30.
lA'aiiiiiif,', io, lo;?;}, (jjo.
Lcliniii, 11., i,-i4.
Loi.l.oss,'k, M. von, 0, 15, 21, 25 1»»
2H,20.30.37.30.«2.73.74.3«,70;
*». «1. !'(>. !»l. .-,.V 02. 03, r,7 04
10.-5. ioo.«i. no, in, no,,.. \^.;
'•■'". 1-!'. 148, .s4. \r,r,. 101 no"
low, 1«4. 188, 2«, 258, 200 "0"'
265, 206. 267. 200. 270. l«l' ;507'
•'508. 300. 310. 358, 2(M>. 210 43o"
446. 450. 458, 450, 403. 405," 407'
rm, 470. 471, 472. 30({. 473 474'
475. .500, ;{•{.•{, ;{.{},, .^o,; ,-,o~ .j^^"
543. mi ;{<};{, .582, .{,^,s(. .r-,oo, (io',,"
400, 885, 5({7, 887, 005, 085
Ki'onowa. ( ». v.„i. 179,785,883.
''•'t>iif,'(', On;!.
l-ciilic, W., 040.
''«'vi, (}.. 143.
ficwis, Mcvan. 201. 078.
I'i'wis, .Maryiiivt. 140.
I'nwis, Morris .J.. ioo;{.
Lfvilcn. K.. 8;i2.
'^'■.vihV, F.. K»2, 147. 273.
Liclillifini, 1070.
liiliciifrl.l, l.'{2, 133.
lAss,uu-v. 11.. 423. 425.427,430. 435
430.400.408.474.
''loyl. •(. II.. 1002.
Lucy. W. A.. 105.
I'ocb, .h, 331, 347. 310.
Iin(.w..til),al, \., 444, 503^ g^o ^jg
!»'")7. Ofi.l. OO.',. !»70. ' '
Loid. .1. W., 203.
I'ovcn, 525.
liiibarscli-Ostcrlay. 104, 239.
Luciani. 240, 1000.
Miflcritz, ('.,884.
liiidwiy. 5.
I^UKaro, K.. 143. 15,3, 150. 378, 379
2H5. i72. 280. 200. .110, 1S3, 311'
I S4. ;{58, 52,3. (i05. !)32 035
I^"ys. .1., 667. 671. 072. 073. 074, 680
«»4, 700. 703, 705, 707, 734 7.38'
78,3, 080. '
^';;;;f '""• ^^- ^*- 1^2. 133. 134, sis,
^lacCallinii. ,T. n., 147.
iMackcii/ii.. ,1.. ;};{o.
Majjiiii, 270.
•Mal.aim. A.. .580. 019,051. 6.M. 654
^ 607. 700. 701. 707. 710. 731!
-'^lall. F. P.. 178, 107. lOS, 181, 120
I ^'4. 104. 10.5. V,Ui. 204. 200 267'
•■W8. 784. 701. 800, 1024. ' '
^fallory. 04.
Matidclstaimn. F.. 788.
Maiicrsi. 288.
Mann, (i., 08. 120, 278, 1«8, .583, 1033.
■^lann. I,., 451.
Manz, 784,
fi
'!
^ \
I 1/
I(>i>2
TlIK NKUVOi:S SYSTKM.
m
ft
Miirciicfi, A.. !»(HI.
MiinliiiiKl. I''., 7H(i, 7»'J.
Murclii'siiii, |:t(i.
Mdrchi. v.. 4r», 107. ',»:;•,', 'iwr,, ',i:(h,'jji,
^'4',', 4:iH, 44:1. 444. 447, 4r.(». 4r);t.
4r.(i, 4r)H, 4r)ii, 4(ii. 4(W. 4ti;i. 51:1.
5.-,;). .'■,70, r.7:t. r.75, r)ii:>. .--(KH. r,i»4.
r>!»H. -)i»!». (ioi. (i(»;i. (;i7. (|.-i4, (LV).
057, «r)l». 0(14. (1(1.*). (11)4. 7(«t. 7I',>.
7!»:!. 7!t."). MKI. 8(1. !»(i;i. !l(14. !»«"»,
11(1(1, !»71.!tHr». 1014. lOKl. lO'J-i. 10'j:t.
MiirKuliL's. A., 44'J, 44:i. 444. 'lU'.t.
Millie, I'.. :!.*).-). 447, •_'1»4, 4."i(). 4">7.
.Miiriim, A.. ^':!!».
Mfiiiiicsr.., (i., 4."i, :.",'<.), ^';i(i, 14(t. I ".T
•,'H!», •^>!((). •^>!).j. •,>!)!», ;t()i. ;io:.', ;to;t.
iJOH, ;(oi». 4(i'j. «-,»a, ijii.
Murk, K. I.., !CJ1.
Murslmll, 11.'!'.. '^4.*..
Miirslmll, .iojiii, 171).
Miirliii, ,!.. 2(11.
Miuliii, I'., no.-.. (l.-»!). 0(14. .S4!», !»',>7.
Miirtiiiolli, ('., l.'i;(, !i7(i.
iMiiSL'lli, K., 28H.
Miisius, Jean. iiT.
Miiycr, C. ;J4, 442. 717.
Miiycr. P., 201.
Mayspr, 2:{1.
Miizzoni, ;i'J2. :{00. 411.
McCliirc, ('. F. W.. 140,
Moder, E., 717.
Mcissn.«r, (J., 7H. H2, 1!)1. 225, 384, 380,
;}'J0. ;«»2.
Melkicli, 411, L»;o.
Melius. K. L.. 107, !)«:;, 102:!, 1024,
(J45, (»4(.. 047. «4S. MU. 102K.
«."»(>. 05 1, 101)0. (►:>'.'. (;:»». 1032.
«r>4. lo.V).
Mendel, K., 2;}l. 004, 831, mO.
Moiiidiiv. 024.
Mcnzcl, O.'iS.
Merke!, P., ISS, 300. 300, 307, 308.
309, 374, 377. 384, .".41. 8.-).'). i»3.s.
Merkid-lJoniift. 12. 104. 300, 424.
Meyer. A.. 1.5.1. 781, (}22, lO.'iS, lO.JO.
Miner, ("., 443.
Meyer, l\, 710. !».-.4.
Meyer, S., .'i4r>. 857.
Muynert. 'I'.. 42. !)8, .WJ, ««7. 008, 070,
072. (iM.V OHl). 713, 714. 71.5, 72.5,
732, 741, 772, 775, 777, 7n3, 80.5,
H12,H0H, 873, 1)71, 10.5H. 1008.
Michel,.!, von. 7HN, 7Ni), 71)1.
Miiialkovies, Vom. 71(0.
Miiloii, 132.
Mills, ('. K., 161.008, 103», 1047.
Minpizzini, (i., 47.5, 0.54, 717, 731.
MiiK.t, ('. S., 40, 104, 748.
Mirlo. 0.57.
Mislawsky, N., 207.
Misslawsky, 014,
MohiiLS 1'. .!., 244.
Moeli, ('.. 083, 1022.
Monakow, C. von, IH, 2H, 44, .504, .580,
.588. 0.50, 051, 057, 007, 008. 074, 07!),
080. 081. 44i>. 0H2, 441, 442, 0H,5,
444, OHO, 08!). 0!)3, (li)7, 0!)8, 700,
701, 702, 707, 710, 727, 730. 731, 708,
7H4, 7H.5, 7i)8, .'»I0, NOO. 802. 814,
.'>l!l. 81.5, .'>22, .',2:{, HI 7, .V_M{, 822,
823, .'i'i», H20, 827. :>;U, :»:{2, 830,
H33, 830, 837, 841. :»4(», 84!>, 852,
853, 801, .'i.-iO, 802, H08, 873, .'».'>»,
87.5. .■>«4. 881. !)49, !)74, 1012, (541,
<}42, 1022, 10.34, 1030, (S(U», ({«!,
1044, 104.5, 1040, 104H. 1052. 1081,
1082.
Mondino. 240.
.Monro. 774.
Montjjoniery. T. 11.. 145.
Monti, A., 71, 132, 152, 230, 240,285,
200.
Morfjenstern, M., 37!), 381.
Morill, A. I)., 30.
Mott. !'. \V.. 251, 200, 441, 444. 403,
570. 574. .580, .583, 500, 3!).), »{Mi,
.504, 5!)8, 509, 000.001, 002, 701, 717,
888. 083.
.Moiirek, J., 288.
:Miiir, H., 4,50. 4.58. 401.
Midler, K., 104, 2;$!, 382,402.
Miiller, K., 717.
Midler, (J. K., 8.i.5.
Midler, lie. .ivdi, 10,443.
:\I idler, .lohanneN 2.5.5, 787, 897.
Mailer, Wilheiin, 537,530.
te.
INDKX <)|.' AirrjIOUs.
Mwnk. II.. 2;{o 007 ,.,,3 .
KHM). km:. ' '
Al'inx,..,-. K.. 04,^ j,»2. -J:J». -in 4.i;{
•J-l!*. .'100. r.TO. r,H(). 717, 7H(| 7i,,'i '
.Mi.nilu/r. W., iwj, loj;,, i,,.-,.-,^ ,„«„
1 (»!»;{
Niljjoli, (ID. I, '54.
NlW'llc, .1., -IfJ, .}4;j
Xanirclo. <■. M.. ioqjj.
Xiiiisi-n. K. 17, 147. ar,7.
Xassc. 'i2',i.
Neiil, II. v., lur,
^(•\n<i, A.. ;((»:{. ;,,.;,.
Nic/ili. W., 71)0.
Nichoii.s, ,1., ;>H!).
Nicimii'k, .*J»ir(.
^i«sl, F..45.(io,07.!m.!,7.;iJ».!,H.|
«l. 104, lOr,. l(),i, 107. lOH, M,!, ,
'"•"•'•"■•. "6. 07, IIT.Os'li
«». Il!», 70, 71, ,^„, |:>l 7..',.
|2;UH11>.1, 12T,iaf<.I..}U.To i;i
ia4. l.T,, i;{G, l.-JH, |;t!,, ,4,, s; n
">«, ''•7,~':il,:.';{;u';{4,;>;jr,.'o;(H'>;{
3-12.-4r,,2HO.J«l.oHo.o„.,. „.„;:„
i<0, mi. 171, of^7, .)(,! .,(,., .„^
2M.a!)7.l'!)!..;i02,;io;{,;iO(UjOM ;7|
••ir.H. (;•,';{. (i;io, 007. ,.;,. ,j-. ^j,^ ^.^,
6H0.80H.H7r..H88,:,({5),!,io,yii .,1.
U2U, !»r)0.
N"Uiimf,'el, II., 747, 1013,
N'ottlidft. A. von. ','27.
N'lisslmimi, 4G, 195.
Oborstoinor, IT., 108, 4.'51, 453, 4(5]
51H, r,2',i, as 7. 300. (il4. «;J3 804
0;50. !)33, 942, 947.
Oddi, K.. 441,444.
Omifn.wicz, M., 502. 8;i«, 84J, 10(i7.
07;{.
' >rrii, K., ;}76.
Osborn, II. p.. lo.^e.
Osier, William. 100. 2()0, 1039.
O.slroiuiiow, P.. 2'2S. 377.
<»ttoleiiglii, I)., 290.
Ow.siannikow, P., 360.
I'aeini, 390, 393.
l*al, 34.
I'aliiiliin). (J., 444.
IVuidi. K., 288.
I'uiii//a, M., 897, 900.
'''il<'i««.n, A. M., 195, 201, 338
''"''•'•'••<. Mi.;,'l, T.. 4(12, 584. 589. 594
•J»7, (101, ((03. •
IVIiicz. I'. I,., 4«.'}.
I't'iiizzi, (f. |{., 444,
IV'rciii, 830.
''•'rgcn.s, K.. 280.
l'<Tlia, 942. 943, 944. «()4, 945.
'V.vcr, ,1., 330, 899.
I'ffiir.T, I{., 442. 44;j.
I'fliicpT. 147.
'''I'lipiH". (1.. 440. 450, 452. 453 4.54
'l.'iO. 458, 4«1.
I'i<'c')|i)iiiini. 840.
I'ifk. .v., 793. 949. 95(1. 957, 102'>
I'ienvt, 428, 473, 1012.
I'ilcz, 108.
I'iiikiis. 921.
I'ilri's, A.. 983. 1003, 1022.
''Iati>. 47, 220.
''lall, .Jiilid M., 1!),-,,
''"Hack. M.. 301.
I'-'pofl". N'., 246. 290.
I'liliylkow. (i., 805.
IVnat, ('. A., 278.
'•'"•'^'■".)>. I'^'O. 012, 135, 138, 139, 967
I'lirtNchcr, ()., 786.
I'lisiiteri, K., 289, 402.
Kalil, 919.
Habl-Klickliaid. II., 100.
liainoii. I). .S.. 775.
K'aiiiuii y ('a,jal, 1'., 800. 811.
Ramon y Cajal. S.. 3, 9, 10, 20, 21, s,
22, 23, 0. 10. 24, 25, 26. 28. 29 3(i
-'J7, 70, «.'{, 77,81. 42, 43,82 44 47
84,92,94.97,128. 141,142. 166* 07'
1H4, 186.260,261.262, i;,7 266 ''>69'
-'TO. 20(;, 2ii2, 382, 402, 459, 465,' 467'
468, 470. 30.-,, 474, 480, 484, 487 3'»o'
•m 502. 334, 505, 511. 512,'33.s'
•'■'1 4, 518. 343,34(5.522. 523, 350'
-•;«), 534, 3.',4, 537, 3:,(5. 3:, 7, 3.-,s'
r.40.3.-.O, 370. 371, 555. 564.577'
-'582, 606, 618. 400, 410, 626 627*
(I '■
ill
!ii
1
1004
THE XKllVOUS SYSTEM.
I-Ji
62!», 412, 4l:i, (i:Jl.(m, 417, (WT.
41«. 0-10, (541. (i42. +21, ('.44. (;-.4.
(ir.ii, 6(!'j. 4;{:{, (ici, 4:u, (i(i4, 4«(k
4«»4, 4«.'», 7(18. 7(i!), 7T(». i«n, 4J»2.
772, 784, ."iO:}, 7!»r., H(l(). .')12, SO:i.
NOO, HIO. KU. .-,15>. .-,27, H21, H22.
8:i2. H;i;{. 8;i7, 842, 84:«, 847, .')41,
542, 8.");i, 804, 855, 857, 858. 85
54s. 54». 8(i2, 8(i4, 8(15, 8(i(i, 88!),
571, !I2(J, 5»4, !»:5.5. (JOO, !t;!8, !l(i7,
072, !»7!», 10.i:j, «55. 1054, <W;5, 1058,
Mil, 108;{.
KiiiilitT, A., 40. 125, 12s, 209, 1S5,
1S«J. 1S7. iss. ls», 1JM», :i50, 204,
2(>5, 2.'{5. 277. .{40. .'MJ4, 42s, 45«,
572, 5SS, <{(»<».
Hanvior, L., .'5, 5», 104, 183, 184, 224,
227, :{0(t, :i8;i, 254, 4i;J, 470, 855.
Kiivn, E.. li)4.
Kawil/, 17, 143.
Roillicli. E., 440, 452, 473, 1036.
Ui'ic'li. yi, 788.
Reii'liiM-t. 607.
Kfid, 802.
Hi'il. 007, 071.688. 002. 097. 714. 717,
750, 1044, 1072, 1074.
Hfinliold, 05(1.
HcisiiiT. .\..421.
lU'inak. K., 3, 102, 142, 197, 899,
900.
Hetzius, (;.. 9, 29. 34. Hi. 3(), 73, 90.
104. 188, 202. 2(U). 15!>. 209. 1«0.
350. 2()S, 361. 211. 212. 3 74. 227.
370. 22!». 378. 2;{;{. 394. 25(t. 257.
25S. 421. 27!>. 4(i5. 499. :{n2, 526,
.'{«1. 540. ;M>4. 751. 47.'{. 752. 474.
475. 47«. 754. 477. 897.
Renter. 919. 5»0.
Rics... II.. 34.
Rclaiulo. 24. 1 16. 473, 474. «.O0, 888.
Roller. ('. F. \V., .■)02, 014. 021.
R(.ini)eiy 191.
Rose, ('.. 381.
Roseiilieiiii. S.. 144, 145, 448, 2»5.
Roseiitlial, 3.
Rosin, IJ., 107, 108, 127, 128, 135.
Ross. .lames, 339.340, 341.
Rossi, l\, 441. 444.
Rossoliino, (J. .)., 001, 602, 604, 716.
houx, W.. 155. 247.
Roth, 413.
Rolliinaiiii, i>83.
iJiil.ner, M.. 249.
RiUliiif^er, .'{40. 5SS.
Riifrnii, .\iif,a>lo, 24.'>, 24«, 390, 247,
391, 24S, 24», 392, 2.50, 39(J, 25.'»,
416, 27.*{, 274.
Riif;o. 19.5.
Ruiiipf, Til., 308.
Russell..!. S. R., 598,0.32,655,901,902.
914, 904, 908.
Ryder, J. A., 302.
SalMii, Eloivnee R.. 318, :{25. 504, .505,
:{.'{5, 507, 508, 509, 549. .'{«7, 568.
407, 411. ()32. (i90, 694, 721, 777,
837, 843, 5».'{, 943, 958, (ill.
Sabnizes. .1.. 289.
.Saeerdotti. ('.. 239, 290.
Sat:lis, n., ()08.
Saehs, II., .52(>, 815, 823, 1059, 1060,
1061, 1082.
Sachs, Iv. von. 155, 372.
Sachs, S., 826, 828.
Sachs, Z., 830.
.Sadovsky, S., 235.
Sala. 0. ii., 259, 200, 505, 032, 849.
Salzer, F., 785.
Saiictc de Sanctis. .'{»2. .'{!>;{.
Siinderson. .1. B.. 1003.
Saiidinann. (i., 894,
Sandnieyer. 983.
Sano. F.', 911. 912, 5S5, 5S({.
Sarlio, A.. 288.
S.axter, T,. 717.
Scii'.iia, 49'\
Schjifer. E, A., 2,1 29, .39. 40. 47. 5.%
307, 59-,. 903, 979, 994. 990. 997,
«:{.'{, 999, •;:;+, looo, 1047.
SchalT.M-. K.. 111. 149, 290, 444, 458,
4()2. 471. 592. 716.
Scliaiier. A.. 167. 108.
ScliielTcrdeckcf. I'., 89, 142, 7», 2.'15>,
441.44(>. 884, 894, 573, 896.
SchifT, !000.
Sehleidon, 2.
INDEX OF AUTHORS.
Schlosin^'er, ir., (584, 717.
■Sclmiaiis, F., 44(5
•Schmidt, 541.
Sehmidf-Ritnpler. II.. 786.
Sc'lmojjfhageii, 805.
Sclmidor, A.. 716.
Sell rci her, 46
S..W,.o,^,.>..,«,4«, «,,,„.„,
Sehiiltze, JI., 141.
Sehultze. Max, 4, 101', 103 ({'» i]o
i;57, 140, 141, 143, r,04, .loo/.j-,.;'
Schulze, F. H.. m-K
Selnvaho, II., 911, )ra), "(Dl
Schwalbc, G., 79, 104. I70, .",05, 525
748, 750, 884.
Schwann, 2. 784.
Sciamanna, E., 1002.
Sclaviinos, (}., 2Ho, ;]82.
Scolt, im, l;J4.
S:d-j\vick, A., 44.
Sfanicni, P.. ;jf)2.
Sherrington, C. S.. 66, 86. 251 009
332, 333, IJH. ij)o_ ,,).{ .j,jy .j.j^'
J38, 3,^415. 463, 554, 576; 983!
Shimaniura, S., 241, l.'J.'i
Shore, 921.
Shiii<(nv.ski, ({70.
Siegfried. 132.
Sieiiierling, K., 7|)o_ 949
Sihler,C., 417, 896.'
Sioli, 1048.
Sniirn,,w, A., 15.34,36, 269, 386, 242
2«S, 41], 2«». '"*"•
Smith. G. ]<:., 10,56.
Socrates. 220.
Solder. F. von. 463, 598, 601
Sottas, .J., 443.
SouidianolT, S.. 290.
Souijue.s, A., 443, 463.
Spencer, Ilerliert, 7, 65.
Spiiler, 415, 458. 1044, 1047
Spirljis, 184.
«i;i"/!<a,E.C., 699,716. 851. 852. 943
9-17, 949, 1031.
um
Spronck, 241.
•Staderini, 926.
Stannius, 234.
Starr, .AI. Aih-n, 10, :{;}9, .340 00'>
Stein, (Jertr.ide, 731,725,875
Stenier, ,1., 316.
Stei)hen, Leslie, 221.
Sliedii. 434, 930.
IJtilling, M..i73.474,581,423,650.
^Iii'lnig, 45.
Sliihr, A.. 1.55.
Strieker. .S.. 103.668,783.
Slroel)e, H., 34.5. 390.
•^';:"'f- ^' «- 'ii'39, 931. 10;5,3,
Strossner. 41,3.
•^trihnpe]i,A.,343,244,423,428,448,
Swierczowskv, 379.
S.vlvius. 734. 9.38. 997.
Symington, ,1., 1056.
S/ymonowicz. W'., 36, .365, 368 «»'»(»
-?-*I, 383, 28,S, 384, 393, 2:,1.' "
'r.-imijnrini. 346. 976.
'i'anzi, 100.
Tartnferi. F., 38. 534. 540, 784, 800
■^'•4, 809, 810. '
Tedesehi, A.. 346, 1 .',({.
Testut, 598.
Teuschor. !{.. 9. 405.
Tlioma, 14;{.
Tl.om.a.s, A.. 290, 442, 513, 553, 655,
^ ')■)., 841, !)(i6, 967,968.
Tlionias, II. M.. 1071.
Thorl.urn, W., 1})4," l{).-i, 339, 340,
i'M».
'I'igges, 246.
Timole..w, I)., 2.'{4, 382, 237.
Tirelii. V., 246.
Toinsii. 279.
T'H'lh. II. Il.,037_4;jy ^^,^
4.)7. 591.
Trepinski. 424. 430, 433, 433, 434
43.5,436,437.
'rrincliese. S.. 272, 415.
'I'umarzew, 418.
ji
I ^
)
1(»5M)
THK NERVOUS SYSTEM.
ii
f
Tilrck, Ii., 235, 227. 30(1, 331, 332, 732.
1012, l()4r).
TunuT. VV. A..r)23,r)(!r).r.70,r)72,3H3,
573. »S-4, SHo, 5H(», 3514, (550, 055.
708. 717, 747, 748, 74!), 06'?, 9(!5.
!»73. 1055.
Tscheniiak, A., 318, 319, 320, 568, o7;\
575, 601, 602, 603. 604, 615. 617, 618,
681, 682, 683, 684, 685, 6!)4. 701. 703,
703. 455, 704, 708, 70!), 457, 45S,
711, 712, 713. 714, 715. 741, 960. 96!».
970. 972, 973.
Tschiseh, W. P. von, 674, 676, 681,
736.
Uiiverricht. 983.
Uskow, X., 194.
Valentin, G., 233.
Valentine, 3.
Vanlair, 229. .'30.
Vas, F.. 278. 1({7, 288.
Vater, 3!)3, 396.
Vejas, P., 654. 716.
Veratti, 140.
Vesalius. 795.
Vialet, N.. 1059. 1061.
Vicq (I'Azyr, 671, 768, 771, 821,
878.
Vieus.sens, 594.
Vignal, W., 167.
Virchow, K.. 315.
Vitzou, A. N., 246.
Vr.lekcrs. ('., 949.
Vollmer. E.. 421.
Vulpian. 22!).
Wagner. R.. 3, 384.
Waldeycr, W.. 5. 12.29. 39. 40, 42, 43.
47. GO. 63. 154. 235. 266. 400. 463, 473.
884, 888. !)04. 913.
Wallenberg. A.. 646.
Waller. A.. 18, 224, 227. 228, 233, 306.
308.
Walsh. .1.. 332.
Walter, G., 261.
Warrington, W. M., 45, 133, 240, 288.
177. 2!)9. 30!», 914.
Watase, 14!).
Weigert-I'al, 627, 694, 728, 777, 859.
968.
Weigert. ('., 12, 25,44. 45, 64. 92, 106,
238. 339, 242, 254, 423, 432. 447, 463^
460. 473, 474. 573. ,580, 617, 621. 676^
V25. 730. 768. 788. 854, 868, 929, 938^
!)57. 964. 986. 1023.
Weinberg, K., 44<{, 45(J, 515.
Weisniann, August, 155.
Weissinann, 413.
Welch, William II., 10.
Werdnig. ().. 71().
Wcrnekinck. 653.
Wernicke. ('.. 671. 814. 818, 830, 832,
1033, 1059, 1009, 1075, 1076, 1077.
Wertheiiner, 983.
Westphal. (".. 423. 428, 448, 473, 484,
917, 942, !)43, 944, 945, 949.
Whitman. (". 0.. 44.
Wiederslieim. 100.
Wiener. II.. 241, 45!), 300.
Wiesener. 154.
Wilbrand. U.. 826. 827.
Wilder. H. G., 40. 161.
Wilson, E. H.. S4. 154.
Wijhe. .1. W. van. 195, 125, 201, 919.
Winkler, (".. 1048.
Wolfstein, I). 1., 43.
Wollenberg. 243.
Wolter. 102.
Worcester. W. L.. 311.
Worotynzki. R.. .598.
Wright, II. K., 288.
Wrisberg, 350.
Wundt, W.. 258.
Yeo, (J. F.. 899. !)00. 1000, 1028.
Young, H. 11.. 37. 421.
Zacher, T.. 1044. 1046, 1048.
Zaf)pert, J.. 451.
Zuckerkandl, E., 748.
SriUECT INDEX.
The numbers in ordinary type refer to nn,ro. • .u
subject is discusso,!: the numbers T„ hi /f '" ^" "'^'^ '" ''^^'^ ♦he
figures in which the objects I" musl^ated" ''' "''^'" '" "'™^"'- «^
^. abducens.
Bechterew), sec
-lateralis super
Abducent nerve.
Aberrant bundlf
Fasciculus veii^
ficialis.
Accessory olivary nucleus, see Nu-
cleus olivaris accessorius.
Acoustic cortical path, direct (Held)
839. ''
tubercle, see Nucleus N. cochleip
dorsal is.
reflex paths in formatio reticularis,
55 7.
Acustico-facial complex. 117.
Acustico-lateral component of cere-
bral nerves, 922.
Acute cell disease (Nissl), 291.
Adendritic neurones, 73, 74, 3(j
Aeusere gram Zone, see Cappa cinerea
weme Lage, see Stratum zonale col-
liculi suporioris.
Ae.merer Kern (Hurdach), 673.
After-brain, see Myelencephalon
Agnosia. 1078.
Ala cinerea, see Nucleus ahc cinerea.
Alteration with rarefaction around
the nucleus (Iloch), 293.
Alveolar zone, inner (Apiithv), 56, .W.
zone, outer (Apathy), m.
Amacrine cells, 82, 44, ,537.
Ampharkyochrome cell, 118, 119.
Ampulla membranacea superior, 3(n.
membranacea lateralis. :{(n.
membranacea posterior, 3<{1.
Amputation, changes in nervous svs-
tom after, 229.
Amygdaloid nucleus, see Nucleus
amygdala'.
Anaxones, 82, 45.
Angeiotome, 19(J.
Angular gyrus, see Txyrus angularis
Angulus lateralis. 7.52.
Anophthalmia, congenital, 823.
Anosmatie animals, 749.
Ansa hypoglossi, l!S({.
lenticularis, 685.
Fteduncularis, 685.
Anterior central gyrus, motor func-
tions of, 995.
cerebral vesicle, 88.
commissure, axones of mitral cells
in, 758.
commissure, termination in gvrus
hippocampus, 764.
lateral nucleus of thalamus, 677
medial nucleus of thalamus, (i77
""cleus of thalamus, dorsal and
ventral, 679.
olfactory lobe, 90, 749, 472.
Antero-lateral ascend in'g ti"act, see
Fasciculus vent ro-lateralis s'uper-
ficialis ((Jowersi).
Apathy's fibrils, 54.
I-^leiHetitargittei\ 60, 273.
\ Apathy, theory of, 273.
j Apex columna. dorsalis, 387.
I Aphasia, 1076.
1097
I (
H
1098
THE NERVOUS SYSTEM.
Aphasia, optic, 1078.
sensory amnesic, 1078.
Apraxia, 1078.
Aqueductus cereliri. 815-321.
Arciied or arcuate fibres, see Fibra>
arcuatu'.
Area of Broca, see Area jmrolfactoria.
parolfaetoria Hroca\ 750.
Ariivodironu' cell, 117, 121, (»7.
Arkyostichochrome cell, 117, 121.
Arnold's bundle, 1044.
Arsenic, action of, on neurones, l(JJ),
172.
Ascending cerebellar tract, see Fas-
ciculus spino-cercbellaris.
Association centres of cerebral cor-
tex, (;7.'», «7«, 1073.
centres of cerebral cortex, lesions
of, 1078.
fibres, lobus occipitalis, (Jfi8.
neurones, 0(»7.
Ataxia, sensory, 1077.
Atrial plexus of heart. 123.
Atropiiy, indirect, of nerve fibres, 18.
Auditory conduction paths, 836.
conduction paths, neurones of, Hii't.
5(><i.
conduction paths, nuclei of, 839.
ganglion, origin of, 186.
nerve, sec N. acusticus.
micleus, see Nucleus X. cochlea',
path, cortical termination of, 878.
sense area, 83i).
sense area, cells in cortex of, 878,
503.
Avalanche (.'onduction, 84.
Axis-cylinder process, see Axone.
Axodendrites, 270.
Axone. 40, 41, «2, 7», SO 4, 78, 103,
142, 145.
Axone-hillock. structure of, 41, 04,
500,82, 111. 10!).
Ax()p"tal impulse, 207.
Axospongiuni, Si. S2. 144.
Basis peduiiculi, riate 1. 5. 441, 442.
BATh of Ford, 430, 070, 730.
Bethe's staining method, 137, 138.
Bcthe, theory of, 272, 273.
Betz cell, 978, ($22.
Biceps muscle, cells i.inervating. Oil,
Bilateral represtntation in cerebral
cortex, 1001.
liinded nii - L inseu kernstrahlu tiij, 686.
Bipolar cells, formation of, 113, 114.
Blindness, mind, 1078.
Blind spot, see Papilla nervi optici.
Blood supply, effect of alterations in,
217.
Blumenau's nucleus, 565.
liodenplatte, 100.
Body temperature, effect of artificial
increase in, 1 70, 302.
Bone segment, 196.
Botulinus poisoning, 301.
Boyce's bundle, 972.
Brachiuin conjunctivum, SO, 311,
312, 313, 314, 315, 31S. 310,
321, 322, 323, 324, 3S0, 414,
410, 423, 032.
conjunctivum, cells of, origin of
fibres of, 659.
conjunctivum, centripetal and cen-
trifugal fibres of, 657.
conjunctivum, degenerations fol-
lowing section of, 653.
conjunctivum, dorsal, middle, and
ventral bundles of. 424.
conjunctivum, fibres from lemnis-
cus lateralii: to, 864, 552.
conjunctivum, myelinization of,
657, 659, 431.
conjunctivum, terminations of fi-
bres of, 730.
Brachium jiontis, 550.
((uadrigeminum inferius, 843, 873,
550.
quadrigeminum inferius, termina-
tions of fibres of, 876, 501, 502.
Broca, an^a of, see Area parolfaclo-
ria.
Brush cells, 4S2.
Bulb, see Medulla oblongata.
olfactory, see Bulbus olfactorius.
Bulbo-hypothalamic neurones, 694.
Uulbo-mescnceplmlic neurones, 694.
SrnJKCT INDKX.
Hiilbo-pontal neurones. 694.
Miilljoiis plexus of liciirf. 123.
Miilliiis olfuctoriiis. rt2U.
layers of, 75,1, 47,s. 47!».
litbuM mm Fhhi, z,,,- Sclileife, C8H
44({. ^
Hiirdaeh's colutiin. see Fnscicuhis cii-
neatiis.
micleiis, see Xiu'leiis funiculi ou-
neati.
B. T. ,.. (von (iu(i.i,.n), see fo.nnii.s-
sura liyiiothalaniiea anterior.
lt»i>l»
f 'alear avis, ({J.'J.
Calearine fissure, see Fissura ealca-
rina.
<'allosonuirfri„al fissure, see Sulcus
oinguli.
Calyculi gustatorii. oS.'), ;{47, 34s.
Canaiis centralis. ;{()>s, !(io.
Cai.pa ciuerea of superior collicuhis
HO!), 810, 5IJ).
t'apsula. externa, W,\S.
interna, lja'niorrliaj,a» into 1014
«41.
interna, motor fll)res in, i)80, J)fS7.
interna, retro-lent iciilar portion of
838.
interna, strucfuiv of. l()o;{ ({;j(j_
(53S, 1007, (J3«.
Capsule of red nucleus, see Nucleus
rubei'.
Caryoclironie cells, 11,>. 117. joo^
Caudate nucleus, see Nucleus cau-
datus.
Cell body of perikaryon, changes in
after section of axones, 333, 234.
Cell liridges (Apathy). «(), 63.
<'ell shrinkage. 3!»3.
Cells of Martinotti. 976.
Cellnlifiigal conduction, l)v axones
3(i6.
by inedullated collaterals. 270.
Cellulipetal eonduction by dendrites
306.
I'entral gray matter of mid-brain,
see Stratum griseum centrale.
gyri, see Gyri centrales.
Central gyri, sensory pail, from „„.-
•lulla to, 704.
'"'"'•"•"•■s of olfactory conduction
path, 748.
optic path. 821, .>27.
sulcus, see Sulcus centralis.
P"tiis of brain (von B.-chicrew)
(''■nlmh> n„„hrnh<,hn, see Fasciculus
tegmenti centralis.
Jl!>hl,'>„jmn, see Stratum griseum
eentrale.
(.'vittn' nnti-n'cur. 674.
nddiun, 674.
»io!/e)i (Luys). 673.
Centre, medullary, of cerebral hemi-
sphere, see ('..„t rum scndovale.
Centrifugal, eerebelhir path, 96,-). «I.'{.
fibres in lemniscus nicdialis, de-
scending. 1017, ({44.
Cent rip,. i,V lib,vs conducting bodily
impulses. 666.
trigeminal nem-ones, central, 641.
Centrum ovale of Flechsig. se'e Tri-
<i»gh; mHimi of Gombault and
I*lnlij)pe.
scmiovale, hallux fibres in, 1027.
Cei)halic myotomes, relation of nius-
eles to, 919.
Cerebellar path, .cntrifugal. 96.1, «13.
Cerebello-cerebral paths. 647, 733.
Cerebellopetal degeneration, 664.
Cerebello-spinal jiaths. 963.
Cerebellum. SJ).
axones entering, 648, 741.
axones from nucleus dorsalis to,
714,
connection with cortex cerebri, 733
degeneivitions following lesioiis of'
964.
worm (vermiform process) of, see
Vermis.
Cerebral hemispheres, see Ilemispha-
rium cerebri,
nerves. <'omponents of, 922.
nerves, control by pallium of, 1022.
nerves, relation to central nervous
system, 917, 588.
UJ^
(i
V
ll(M)
TllK NEHVOL'S SYSTEM.
( 'crchral nerves, sensory components
of, 924, M'*.
vesic^les, HH,
('crel)ro-s|)iiiM' itis, nerve cells
in, 175.
Cerehnini (brain), up:!, ,'{40.
cortex of, see PuUiiiin.
Cevvieul enlargement of cord, sec In-
tumescentia cervicalis.
sclerozones, ItiU.
Chromatic zones, oti, 58.
Chromopliile colls, II.'). IS.'J, 73.
C'hiasma opticum, 1M>, oOS. 7!»r».
opticum, decussation of fibres in,
7N.-).
opticum, (le<,'eneral ion of, TM!>, .'>()4.
Cingulum. 10(>1, <!<>!).
Circumccllular plexuses. 11.').
Clarke's nucleus or column, see Nu-
cleus ilorsalis.
Claudius, cells of, 3(>4.
('lava (did)), .')()(», ,'{7*J.
Clind)iug fibres. Ho, .')2.
Column of Tiirck, see Fasciculus cere-
bro-spiiudis vontralis.
Cocldcfir root of auditory nerve, see
N. cochlea*.
Ccdom, unsegmcnied. I!t7.
Cold points, ^^hi.
Collaterals, 21, 22, !»0.
from axoncs of pyramidal tract,
l();i;i.
reflex, 2(5.
Colliculus facialis, ti'2.
inferior, .'{14. SlS. :{1», .'{({{J, 3S2,
Tttio, 838, 84:{, 847.
inferior, relation to auditory path.
87:5.
superior, 31(J-:{'-»4, tW.). .'{St».
superior, fibres from lateral lemnis-
cus to, 8(58, .'».").'i-.').'>S.
superior, fibres to occipital cortex
from, 81!).
superior, path to spinal cord from,
i»6!».
superior, termination of optic fibres
in, so:}.
superior, zones of. 808, 809.
Columna cxtrendtalis inferinris, 914.
extrenutalis superioris, !)I4.
),n'isea dorsalis, ,'{7I{.
{;risea ventralis, .'{74, 4()7.
inleruiedio-lateralis. 9i;{, ,'>8,i, 586.
lateralis, 915.
nu'dialis, 9i;{, 5S5, 5S(». 915.
posterior, see Columna grisea dor-
salis.
Comnni of Schultze, ;i90, 2{)5-'i»H,
448. 451, 454-457.
Commissiira. ansataof llannov('r, 807.
anterior alba, see Commissura ven-
tralis all)a.
antisrior (cerebri), 1055, (>(>(».
anterior grisea, see Commissura
ventralis grisea.
cerebri maxima, see Corjius callo-
sum.
dorsalis (spinal <!or(l), 474. .'{()5.
hippocampi, 7()(), 1057.
hypothalaiiuca anterior, 807, 517.
hyi)olhalainica media (Meyncrl),
'7i;{.
inferior ((Juddeiu), 507.
posterior (cerebri), :{*21, .'{22, .'{H«,
411>.
superior (Meynert). 5()7, 514, 515,
713.805.
ventralis alba. 387, liiH).
ventralis grisea (spinal cord), 387.
Commissural cells, see Neurones, het-
eronu'ric.
Iil)res of cerebrum, (U»5.
Commissure betwecMi Bechtercw's nu-
clei (ventral part of brachium
conjunctiviim), 315, 311>-3t,'3.
415,(5:52,420.
between inferior coUiculi, 315,
414.
optic, see Chiasma opticum.
Conarium, see Corpus j)ineale.
Concrescence (Hehl), 50. 70, 94.
Conducting anastomosis (Apathy),
(iO.
Coiuluction avalanche, see Avalanche
conduction,
path. ;{19.
SUBJECT INDEX.
101
('omlii(!tioii path, sensory, from me-
dulla to I'ctilnil '^\v\, 704.
path, soiiia'stliL'tii', resume of, TiiO,
4«!>-471.
Coiidiu'tor sonorus, H40.
Coll fusion zone, !)!)."), (JiW. ,
Connecting plexus of heart, 123.
Contact tlicory of transmission of im-
pulses, 2ti2, 20;5.
Convergenzcentrum, t)51.
Cornu aninionis, sec Ilippocampiis.
antcrius, sec Ventriculus lateralis.
inferius, see Ventriculus lateralis,
postcrius, sec ^'entriculus lateralis.
Corpora albicantia (white bodies), see
Corpus mammillare,
gcniculata, seeCor|)Usgeniculatuin.
(puidrigcmina, S5>, 372, oliO.
quadrigenuna, relation of lemnis-
cus lateralis to, 7)7i{\.
quadi'igcmina, signilicance of, in
animal series, 804.
(luadrigemina, terniination of optic
fibres in, 8013.
Corpus eallosum, 1053.
callosum, degenerations of, 1055.
ciliare, see Nucleus dentatus.
dentatum, see Nucleus dentiitus.
geniculatiini laterale, 536, 800, 813,
:)11,82:5, 831.
geniculatum laterale, degeneration
of cells in. HIT. .VJO.
geni(;ulatum laterale, nuclei of,
67!l, Tl)(), ilO.
genicidatum laterale, termination
of optic fibres in, 7i)8. 800, olO.
:»12.
geniculatum medialc. .'JS(), 843, 847.
geniculatum mediale, degeneration
in, 875, .").'){).
geniculatum mediale, fibres to in-
ternal capsule from, 875, 5(»0.
geniculatum mediale. nuclei of,875.
geniculatum mediale. ternunation
of optic fibres in, 804.
liuysi, see Nucleus hypothalami-
cus.
mHmmillare, JK). 3H«.
Corpus mammillare, connection of
hippocampus with, 7<i(>.
mamtniliare. nuclei of, 708.
parabigeminum, 56i), 3H(J.
pineale, »0, K\\.
restiforme, :j(M>-:n2, 31S-321,
377, 3S:>, 504, 575. SlU, 412,
413, 417. 41 ». 580. 587.
restiforme, degeneration following
section of, (J 14, (Jl.'i, Wu.
striatum, H{).
subthalamieum, see Nucleus hyjio-
thalamicus.
trapezoideum, 313, 324. 3(»7-3r>»,
551, 553, 402,41.j, 41 7, 012, 537,
.->3S, 843.
trapezoideum. transverse fibres of,
850.
trapezoideum, terminals of axones
on cells in, .■)4.'>, 540, 547. 857.
Cortex of human brain, (}(i3.
Corti's membrane, 3(J2.
Cortical l(>minscus. 007, 690.
Cortico-muscular conduction path,
1037, (>r)7, (J.'»8.
Crista aiiipullaris, 490.
Crossed ]iyramidal tract, see Fascic-
ulus cerebro-spinalis lateralis.
Cms cerebri, see F'edunculus cerebri.
Cutieate funiculus, see Fa^riculus
cuneatus.
tubercle, see Tubereulum cunea-
tum.
Cuneus, r»24, ii34, PI. I, 3.
Cylinder furrow, KMK
( 'i/liiiilrodendrifen, 90.
Cytochrome cells, 115, 121.
Cytodendriten, 370.
Darkschewitsch, nucleus of. 721, 724,
4<;2. 4(J3.
Deckfilalte, KM).
Deafness, mitxl, 1078.
word, 1070.
Decussatio brachii conjunctivi, 310,
322-324, 415, 42<>. 42».
lemniscorum, 30H. 503. 447.
nervorum oculomotorium, 942.
r I
1102
THK NKRVOUS SYSTEM.
Deeussatio ncrvoriiin trochk'iu-iuin,
;II4, 940, (M)2.
|.yniiiii(luin, Dbl, !)!)0. UDl, «24.
siibl Imliunioa anterior, see ( 'oininis-
siini liypotlialiunica aiilcrior.
tfj,'iiR'iili (lorsaiis, 772, !)«!), i'.io,
4»2, «17, «1S.
tojjinenti ventralis, 4*i{>, 4:J.'>, (»1J>,
!»71.
Decussation in optic cliiasin, com-
plete (von fJuddcn). T!»0.
in optic cliiusni, tiicorics oi', 78'1.
of fillet, see Uecussatio leninisco-
nnn.
of pyramids, see Decussatio py-
ramidmii.
Dcctissationcs tcginciilDriim, ']1(>.
:U7, 324. 40.>, iUi, 4»;{. 4».i,
772, 813. !)69.
Deep cells of niitdi'i X. trigcmiiii, 043.
optic path, H31.
Degeneration after amputation. 338.
after lesion of cerebellum. i(64-!H)7.
after lesion of gyrus centralis pos-
terior, 703, 450.
after removal of eye, 787, .")()4.
after section of cor|)Us restiforme,
967, (;i4, (Jl.').
of cell-body on removal of affer-
ent impulses, 2'2U, 177.
of nerve cells after section of axone,
333, 334.
retrograde. 339.
secondary or Wallerian, 18,46.234,
337, 143. 144.
Deiters, cells of, 3(»4.
Deiters' nucleus, see Nucleus N.
vestibuli lateralis (Deiters).
nucleus, tract to spiiuil cord, 311,
312.321.322, 3«S.
Dendraxone, 14. 70. 41, .">.">.
Dendraxones between U{)per motor
neurones, 1036.
Dendrites. 4, 15. 1<». 37, 70, 111, 189.
effect of injury to, 339.
origin of, 169.
theory as to nature of, 258.
Dermatomere, 196.
Descending centrifugal bundle of
lemniscus niedialis, 1017, (»43,
<t44.
cerel)ellar spinal tract, 963.
spinal neurone system from forma-
tio reticularis, uncrossed, 963.
spinal neurone system from nu-
cleus ruber, crossing. !(73.
Diaphragm, dcvclopnu'nl of, 124.
innervation of, 194.
Diazonal nerve lnitd<, 309, 137, 138.
Dience|>halon, 1")9. S{>.
motor neurones in, 969.
Diffuse cells of retina. 7H3.
Dijilomeric mus(des, 301.
Direct cerebellar tract, see Fasciculus
spino-cercbellaris dorso-lateraiis.
pyramidal tract, see l''asciculus
cerebro-spinalis ventrali.s.
Dirccte (iciinfische RindenbaJm,
(Held), 868.
Rindcnttchhife, 607.
Dorsal commissure, see Coinmissura
dorsal is.
decussation of tegmentum, see De-
cussatio tegmenti dorsalis.
funiculus, see Funiculus dorsalis.
horn, see Cornu dorsale.
nucdeus of lateral geniculate body,
079.
iniclcus of reticular zone, 677, 079.
root, see Uadix dorsalis.
white matter of nucleus hypotha-
laniicus, 684.
DiTi7,((ntpulni/in (llelweg). 958.
Ductus cochlearis, 301, 3(>2.
cndolymphat icus, 3(>1.
reuniens, 3(>1.
semicircuhiris lateralis, 301.
utriculosaccularis, 3(>1.
Ectoblast, 165.
Rhrlich's vital staining, 31.
Electrical stimulation of cerebral
cortex, 993.
stimulation of neurones, indirect,
370.
Elementary fibrils of Apathy, 54.
m^
SUB.IH(T IN'DKX.
ii(i;5
HIementargitter, seo Apiitliy's AVe-
menl>ir(jU,ter.
Kinliolus, sec NucliMis cmboliforiiiis.
KiiiiiuMiLia iiilLTiifdiinculiiris of istli-
III us, iJO.
Kiiiir yochroino wUs, 118, 110, «8.
I'iii<'('|ili)il(>ll, l(i3.
KiHl-hriiin, sco Toloncoplmldii.
Knd-ldilbs of Krause, 2.') I. ;!!»:.'. :!!)«.
Kiiliirgc'inciits of cord, see liiluines-
eontiuB.
Eiiloroiiiere, 106.
Kiiliy zone, 42;{, 434, 427.
Kpislnituin, 500, 781.
K|)itlial(iiinis, 80.
iv|iiivalent picture of nerve cell, 1!}3.
h'isa/z-Theorie of tabes (Kdiiiger),
254.
External capsule, seo Capsiila ex-
terna.
Extirpation of facial area, (J.'il. 1030.
of iiallux centre, <i4(;-(i.iO, 1024.
Eye, development of, IIS, IIJ).
muscles, innervation of, or)(».
Eyes,eirectsofextiri)alioiiof, 7H7,.»04.
Facial area of cortex, extirpation of,
O.')!, 102!).
nerve, see Ncrviis facialis.
Fades medialis cerebri, motor locali-
zation in, 1000, (};{4.
Fasciculi cci-ebro-spinales pyrami-
dales, 172, 313, 3U, 315, 31 (J,
317, 374, 37(5, 377. 07"), 081,
1008. 1010. «25-(»31, ($40.
cerei)ro-spiiiales pyraniidalcs, nicd-
uHulion of, 087.
longitudinalos (pyraniidalcs). see
Fasciculi cerebro-s[)inales.
pedunculo-inaininillarcs, 708. 4{)2.
peduncuio-maminillares, pars basi-
laris. 3S(;, 772.
peduiiculo-niainmiilares, pars teg-
mentalis, 772.
proprii, motor neurones for, 9')2.
Fascii'ulus anterior proprius (I'Mecli-
sigi), see Fasciculus ventralis pro-
prius.
Fasciculus antero-lateruiis superfl-
cialis ((Jowersi), see Fasciculus
ventro-laterali.s, etc.
ba.silaris medialis, (J!!5-(>*JJ).
centralis tegmculi, 401, 403, 404,
728, 074.
cerebellaris lateralis descendens,
66:5.
cerebello-spinalis, see Fasciculus
.spino-cerelu'liaris dorso-laleralis.
cerebro-spinalis anterior (pyrami-
dalis anterior), see Fasciculus
cerebro-spinalis vcul ralis.
cerebro-spinalis lateralis ([lyrami-
<lalis lateralis), *ilSl, *JS*J, 30(>,
;{00, GOO, 084, 002, 030, «31, 1045.
cerebro-spinalis ventralis, 30(),
soo. o;i;}.
cerelu'o-spinalis ventralis of mon-
key, 1027, 040.
cruciatus, 785, 507.
cuiiealiis (Burdachi), Si5, 280,203,
205. 301. 302. 304.308,318-
322, 372, 373.370,405, 44;J-
457, 401, 402, 4(58.
dorsalis proprius, 550.
dorso-lateralis (Lissaucri), 25, 280,
281, 3SM), 42:i-4.'i5. 408.
gracilis (Golli), 8. 2({. 304, 308,
318-322, 372, 373, 370, 405,
40(>.
gracilis, degenerations of, 280,
2{>2, 203, 442-447.
gracilis, origin of. 4;i0-442 ; termi-
nation of, 301, 302, 4(il. 402.
liitcralis limitans, 008, 0()!). 3JM>.
lateralis proprius (Flechsig), 300,
415,550, 011-614, 740.
lateralis ventralis, 740.
longitiidinalis inferior. 1065. «»72.
longitudinalis medialis, 300-317,
310-324, 380, 401. 404-400.
414-417, 420. 6i:}-61!). 627,
637, 422, 668, 675, 718, 721.
longitudinalis medialis, connection
with cord, 450.
longitudinalis medialis, motor neu-
rones for, 959.
rv
If
(.
f
1104
TIFK NKUVol'S SVSTKM.
Fascit'iiliis lotiKitiKlinalis superior,
881, ion;{, «71.
iiKiciilaris (•riiciutus, r>()7, 7!)").
muculiiris iioiicniciutiis, dorsiilis et
veiitnilis, 'i07, VXt.
niftrtfinalis anterior, 957.
ii()iu'ni(.'iutiis, 7K.-., oori. .-)()«;. :,07.
(iciipitiilis triiiisvcrKiis c'unei, 1000.
iH'i'ipitiilis tnuisversiis f,'vri liiigii-
ali.s. 10(U.
occipitalis vorlicalis. 10r)9.
oceipito-fruiitalis, lOtJH.
paliio-froritalis, 1()4(».
pallio-frontalis, (legciicnitioii of,
mi.
retrollexup (Meynerti), 317, 323,
3'Jl, 3H«, 775, 777, 4«S.
retrollexus (Meyiierti), relation to
red nucleus, 45)1), 778.
.spino-cerel)ellaris dorso-lateralis,
3()S, 320. 575, 3»(). 585-589,
3!):», 3{)(;, 975.
spino-ccrel)ellaris veiitru-lateralis
rcstil'oiiiialis, (iOIi.
thalanio-iuainuiiilaris (Vicq d'Azy-
ri), 3S({, 708, 771.
unciiiatus, 1000.
veutralis jM-oprius, 559, 30«, 30.S,
401, 40«. (ilO-014.
vciitrolateralis .superficialis (Gow-
orsi). 559. tUH. 302 30(J, 3J)0,
590-598, 3{)«, 3S>7, 3»!S, 001-604.
Fatigue, influence of, on neurones,
270, 277. 1«4, 1«J({.
Fi'/d II, 655, 43(J, 071.
Fe/d 1I„072. 438.
Fehl Ih, 072. 438.
Feld Ha. fibres from fasciculus longi-
tudinalis niedialis to, 008.
Feltwork (Neuropiluin), 17.
Fibric arcuata' externiB, 308, 370,
505, 575.
arcuatns interna>, ilOH, 30{>, 320-
324, 56:5, 565, 508.
arcuatiB interna- from nuclei tcr-
minales X. trigeinini, 422.
arcuatjr interna', relation to nucleus
alai cincrea', 024.
Filira' arcuttla> interna', relation to
nucleus funiculi cuneati, 420.
arcuata- interna' (vestii)ular), 31}),
027, 800. .'>:»«.
poiitis, 312.
Filirrx cor'Iro-rithi-iqHes di'irctcti, 732.
Fila olfacl.-ria. 478, 500.
Fillet, see licmniscus.
Ki.ssura calcarina, (538.
eerct)ri lateralis, Plate I, 8.
cliorioidca, 00.
parieto-occipilalis, I'late 1, 3.
prima, 749.
rliinica, 749.
Sylvii, (>33.
Fif<.siirenKtntn(/, 960.
Flechsig's embryologica! method, 25.
sensory systems, 7;i5, 4(>(>-408.
Flocculus, 372, 411.
peduncle of, sec Pcdunculus floc-
culi.
Fontnini'iirtige ll(tuheiikre\(zunii of
Jleynert, see Deeussationes teg-
inentorum.
Food-stulTsof neurones, 218.
F(jrebrain, see I'rosenccplialon.
Forel's ventmlc /Iaidie)ikn'iiziini/,7~2,
402.
Formatio aremita, 100.
reticulari.s, 176, 015 728, 401. 412,
404, 4(»r», 500, Oil. 618, 629, 690.
reticularis alba, 727, 959.
reticularis grisea, 721, 960, 460.
reticularis. optic and acoustic fiiires
in, 557.
l<'ornix, 1067.
Fossa cerebri lateralis (Sylvii), Plate
1,3.
Fovea, anterior or superior, 372.
Funiculus anterior, see Funiculus
ventralis.
dorsalis, 22. 56:5, 300.
dorsalis, fibres from nuclei of, 709,
711,71:5.
dorsalis, function of, 709.
dorsalis, injury to, 708.
dorsalis. myelinization of, 281-288,
424-4:57.
SIIIUKCT INDKX.
lion
l''iiiiiciiliis(lnisiilis, orifjiii of, 4r)7-4(ll.
liilcialis. H, :ttO, :ni. 40.T!)1.').
liilcnilis, lilnf hv■^*t^■lll I'miii imi'lciis
ruber to, 4'J2.
|icslcri(ir. svv Fiiniciiilus ilorsiilis.
veiilrulis, tlTil.
ventro-liilernli.'s, llbri's from Di'ilcrs'
nucltiiis to, !l()0.
Fusum'/ileiJ'e (l""lcclisig), ()H4.
Ounglia, spimory. (m«11s of, OH, :{1, 17!»,
108.
trunci .symiuitliici. 1!H), is.'i.
nutif^lion cells uf A|mlliy. "»'-i. •'")4.
coiiiini.ssunilL', sue Nucleus coiiiiiiis-
su rails.
f^ciiieuli, ■)!.'!.
luilx'uulu', sec Nucleus Imbciiulii*.
juj,'ulare, 478.
nodosum, 478.
petrosum, 478.
scmilunare ((iasscii), 514.
spinalc, 185, 1m:{.:{1(),;j11.'2O7,20»,
21U.
spiralc, 112, 117, 545.
sui>erius. 478.
vcstiliulan; (.Scarpa"), 499.
Oanglionic ridge, KM).
Uasserian ganglion, see (langlion
.semilunare.
(lastrocnemius muscle, nerve endings
in. H!I4.
(Icmmulcs, 7C, 37, fi*) ; loss of, 240.
Oeniculato body, external, see Corpus
geniculatuin laternle.
body, internal, see Corpus genicu-
latum mediale.
Genital corpuscles, 2.>«, 2(;i. ;«)fi.
tieiui cajisuhc interna', 1005.
N. facialis, 3«8, 411. !i;iO.
Gerlach's dilfuse network. 7. 60.
Giant cells of substantia gelatinosa,
(m. 421.
l)yniniidal cells, 078, «21.
Oiilcrschicht^an, 438.
Gittei-Kch icht/cenie, 679.
Cilandula pinealis, see Corpus pinealo.
pituitaria, see Hypophysis.
Globus pallidus, Plate I, 3.
Glomerulus olfactorius, ."»(), 5:M,
757.
GolKi'scell of Type I, 11, 12.
cell of Type 11, 12, 13.
cells, Type 11, inlcrsegnu'ntal. 9.52.
cells. Typo II, between upjier and
lower motor neurones, lOltd.
ditfuse network, 15.
Golgi-Ma/zoni corpuscles, 2.'».'», 31M{.
(iolgi's melliod, 9.
Goll's fasciculus, see Fasciculus gra-
cilis.
Gowers' tract, see I"'asciculus ventro-
lateralis superficiaiis.
Gracilc nucleus, see Nucleus funiculi
gracilis.
Grande lobe limt)i(pie, see Gyrus for-
nicatus.
(irandry's corpuscles, 220-224.
Granule layerof Fleclisig's tvtn/torale
liiec/i.yihdre, 759.
Gratiolet's radiation, see Hadiatio oc-
cipito-thalamica((iralioleti).
Gray commissure of cord, see Com-
missura grisea medulla' spinalis,
matter, central, see Substantia gri-
sea centralis,
suiistance, see Substanlia grisea.
(/i'u,ss/iir)i, see Cerei>niin.
Ground-bundle, antero-latt'ral, see
Fasciculus ventralis |iroprius.
Gryochrome cells, 117, 121.
Gudden, commis.sure of, see Commis-
sura inferior Guddeni.
law of, 18, 44.
Gustatory conduction path, central
neurones of, 747.
neurones, see Neurones, gustatory.
Gyri cerebri. Plates I and 11, (»3S.
occipitales laterales, Plate II. 1,
<i38.
occipitales superiores, Plate 1, 3,
«38.
Gyrus ambiens rhinencephali, 752,
501.
angnlaris, 823.
centralis anterior, Plate II, 1.
!i
M
1 1
i f
Hot;
TIIK N Kit vol's SYSTEM.
(iyriis cctitnilis pontiTir.i-, Icsidn of
(Fli-eli.si),' 1111(1 Miicscl), TIC", 4ri,',.
I'iiiKuii. IMiilc 1, 4, «;j,s. ((((]>. 1(1(11.
foi'iiiciiiiis. i'iiilf I. ,'J.
fi-ipiiliiiis inrcrior, I'll Ic II. |.
froiitiilis iiicilius, I'liilc II. I.
frdnliilis superior, I'liiii'lioii of. UUI).
Iiippiiciiiiipi. 7(;.i,
liriituiiiis. IMiiti^ I. 4.
oll'iictoriiis lutemlis, 751. 473, 474.
47.V
olt'iicloriiis lucdiulis. 7."»1, 47S.
Sfriiiliimiris I'liiiiciiccpiuili. 752.
siiiiciillnsiis, .'lOI, .'•(►•i, (».'{N.
siipriiiniii'u:iiiulis, Plate II. 1.
ti'iii|Hiriilis iiu'iliiis. I'liilo II, 1.
tfiiiporiiiis superior. 'Mi, H78.
uuciuatus, see Uncus.
Hair iM'lJs of oi'fj:aii of Corli. lUH.
Hallux ceMtre,(le<;i;nerat ion following
extirpation of, <i44>-4».'>0. in-,>4.
centre, pyramidal lilires frnm, KKK).
eentre, decussaiion of. lO'Jd. (»4H.
//(iii/i('iiln"ui(/i'l (/cs /jiiiKi>ii/iernea,674.
(li'f< ntf/wn Kcnu-x, (i74.
(Ic-s TlialtimuK. (!74.
of von (luddcn. see Fasciculus pe-
dunculo-nuunniillaris.
noiihrnfdsnMn (l-'orel). 435, 670.
//itH/x'iik'niiziiHt/, see Deeussutioncs
tegnientoruni.
Hitiihi'iiHtrahlunii, 607. 7!iO.
//iiii///,sr/;li'ifi',iiL'e Lemniscus niedia-
lis.
dcr Sc/ileifenscfiiclif, ()«7.
//iiiip/f/iei/ dcr ScltlcifenHchicht, (187.
Head area of cerebral cortex. i)!)8.
cavities, i)18, Dili,
fold. SS.
plate. SM.
Heart, plexuses of, 123.
Ilecateroinoric neurones, see Neu-
rone, liecateronieric.
Hold's method, 12!».
Hemianopsia, Hi.'). H26.
llemispliariuni cerebri, lateral sur-
face, 675.
Ilendsphnrium corebri, medial sur.
face, (176.
II( iiiisplierie bundle of von liudden,
807. .'»l<t.
Hensen, cells of. :{«4.
I lerbsl'.s corpuscle, «eo Pacinian cor-
puscle.
Heleronu'ric neurones, see Neurone,
lieteromerie.
//f/cni/Kiili're Scrrenzclloi, HI.
Hibernating animals, nervous system
of, 2H0.
Hilus Ihalami, (Ih:!.
Hind-brain, see .Metencephalon.
Uinli-rc [jaiiyshihiilil Fnnnufioii (llo-
neH:Ker). 727, 7:12.
nippocam|ius, cells of, (IH, 72, H't,
connection of uncus with, 4S{).
//ini/,/<i/t/ii'nsr/ili'il'i' (.Meynerl), 868.
///;;/.s(7u'M/.('/.sr//////(/( of Flechsig.(i85.
Hoclie. researches on pyramidal
tracts. 1((1(!.
Homonymous bilateral hemianopsia,
78!).
Horseshoe commissure of Werne-
kinck, (15;i, 42«,>, 430.
llypof,dossal nerve, nucleus of. !)24,
M,t.
nucleus of lioller, small-celled, !»26.
Hypothalamus. JMK
liiyers of. (171.
limits of. 671.
paths to, 6(!H.
region of, (UK!.
Iiiiixones, HI.
Individuality of neurones, 38.
Infections, changes in neurones in,
28! ».
Inferior collicidus, nucleus of. see
Nucleus colliculi inferioris.
colliculus. relation to auditory piilli,
872.
fillet, see Lemniscus lateralis.
Infraconscious impulses, 250.
Tnnerer Keni (Hurdaeli). 67!1.
fnsehvhwfUi' (Schwalbo). 750.
Insula, Plate 1, 3.
snUKCT INDKX.
ll(>7
liilcr-liraiii, hw Diniii'i'pliiilon.
lull rccllularliridp's.sfi' Cell liridKi's,
Iiilfriiisiilar j'clls. 421.
Iiitcriiu'diary liiniina iiu'dulliiris, 4:in.
iiinliir iiciiriiiics, ))"»!•.
Iiilfi-iial tapsiilc, sci> Capsuia iiitcnia,
IntcriuMiroiiul rolatioiis in ciMvltral
cortex. <{.'>.'>, <{.'»({.
siihslaiicfs, !H».
liilnrolivary layer, sfc Stratum iiitcr-
ulivari' li'Minisi'i.
liitcrsf^jiiu'iit, liMi.
Iiilcrstitiul ci'lls nf sensory nufU'us
ot' trip'iiiiniis. (M',\ 4*il.
Iiitoxicalioiis, clmngcs in ncunmi's in,
aH2.
Tiilc'r|iari('lal sulcus, see SuUmis inter-
puriclalis.
Intunicsccntia cervicalis, motor neu-
rones of. MHr.. i)(t.-|. .'iTH^.'iS'i.
luinlialis, neurones of. yST.
Irritaliilily of neurones, 34H.
Island of |{cil, see Insula.
hluirs i>lf(i/iru'i. 7(H, 4S7. 4HS.
Istliiuiisof brain, see Isthmus rlioui-
iienre|ilitili.
riioinlience|iliali. SU.
It el' a tertioad (juartuin venlricnlum.
see Ai|Ueduetus ccreliri.
Kaiser's nucleus cxtremitatis superi-
oris, i)14.
h'fiiiizi'llrii, 107.
Kurpi'rfi'ihlspltiiro, (l(}7.
Krause's (>ud-ljull>s, see Mudhultis of
Krause.
Kreuzende 1 1 i iitc r.il va nfilifni-d rona-
/lininitdi'iiKi/xtcDi ('rseiiernuik).
714.
Ilintevstrdtxikcrn - (/rofitihinin'iKl-
Tlxditni UMi/xIciii ('rseliernnik),
714.
Tialiyrintlius nienilminaeeus, S(>I.
Liimiiui basilaris(('orli"s uryan), ;{(>i,
8((4.
terminalis, 1>0.
La(iueus, sei! Lemniscus.
liarKc-celled inieleus of tluilamim
(Nis>l). (177.
Lateral eolunin, sec I'lmiculus la'er-
alis.
lillel, see liemni«eus l.ilcralis.
;rcnieidate liiidy, -ec Corpus ftonicu-
latiiui iatel'ale.
horns, j;roupin>,' of cells in, HHH,
.'»((M.
line. -.2110.
nucleus, see Nucleus lateralis,
inu'leus of corpus nuimuiillare, 7(IH.
nucleus of reticular /one, 077.
nucleus of thalamus, anterior and
posterior, OHIl.
pyramidal tract, see Faseieulus
ccretiro-spiiudis lateralis.
Liiti'iidrx (dmlcii/iudiM Kleinliirn-
hiiiidel, mil
Lauteruuinn's sej,'uu'ntation, 4.
liCj; area of cortex, !M»H.
Leitiiiij/slKi/ni, iMl>.
Lemniscus or hKpu'us. OSO.
lateralis, :n4, .'{l.V :ns-:W2. '.W.K
:is«, r,r,:\, 404. 4o:», 414, 4ir»,
('•87.
lateralis, divisions of. HOI.
lateral's, libra' anuata' interna*
from, •<('(), 'ut'.l.
lateralis, finer struclure of, HOO.
lateralis, lesions of. 801, 550.
lateralis, nuclei of. 804.
lateralis, origin of axoues uf, 803,
551.
lateralis, relation to nucleus collic!-
uli inlVrioris, 8(58.
lateralis, termination of axones of,
800. 554.
medialis, :jl.'{-S17, liHH, 504, 570,
401, 404. 414, 415, 087. 089,
44s. 440.
medial accessory, 088, 44(».
medialis (accessory bundles of von
Beehterew), 404.
medialis, descendinj,' centrifu^'al
bundle in. 1017. «4:{, 044.
medialis, dii'eet tilires to cerebral
cortex from, Oi)i).
•\|
^
lios
'I'lIK NKIJVorS SYSTIOI.
is, oriiiiii of lilii'i
I'iniiisciis inciljiil
<>r. »!M.
iiu'diiilis. Ii'i'iiiiiiiiliiiii (.r 111. res dl',
<;!M. i.v>, i.-,i.
s I'oiKM'i'iiiiiir cniirsi'
mcdiiilis, \ ii'w
<>(, l.'>|. (1(1(1, (i!i;.
suiicrior. .'120, .'It! I, .MO.
liudiMcnlum spirnli" cnclilci', ',Ui'2.
I.iiiicii insula'. T'll.
LiiisnihrniKr/i/iiH/i' ( I'Mcclisij;), (185.
1
I.i
ssiuicc's ('oiiiiiui (I)' tnii'l.
!•'
Miiiilii'. si-o I'liliiiiiii.
Mnivhi's iii.-iliod, I"). :>|'j, 'J4:t.
Miirt;iiiiil ImiiiiIIi- of liissiiiiiM',
SCO
l''iis('i('iiliis iliiisu-liilciiiliN Lis
simcri
ciciiliis (Idi'sii-lalcriilis l.issiiiit'i'i.
liobiilus piiraciMilniiis, ruiicli if.
imniccnti'jilis, lesions nl', Tdl. I't't.
Ij(>l)ns (ifi'ipiialis. 101?.
olfacloriii.s. m, 74!», 47l!.
Ijociili/alion, inoloi', in spinal roiil,
H!»!).
(if rmirtioii in ccrcln'Ml cortcN. W'y.
KKfJ.
of I'miciiDn in spinal cord. !Mi:t
!l()."i. !tO!t, :»S.'{.
Locus caTiiicus, .'{7-.
lion^'il uiiinai liuncllc. poslci'ior nr
dorsal, sec l'"iiscicidus lonuiludi-
nalis incdialis.
liowor lace ;nva. !I!IS.
fticiid nerve, !•;!(».
motor noui'oncs. sec Neurones,
lowci' nioloi'.
l-unibjir cnlarccnienl of cord, sec In-
tuinescenlia hiniii.ills
I
uys' liody, see Nucleus livpollia-
lainicus (corpus laivsiiv
I/Vi'ii. see (
iiniinissura hippocampi.
Maci'osinatie aniinals, 71!).
iVIacula acus(ica .sjicciili, .'Ct.'t. '.U'*\,
M
.)(i(».
aciil:i aci
islii'u iilriciili, ',U>\.
.Mi
liilca. M'J,'). .M-JC.
lulca. lilires in opt ic nerve from. TDo.
Is of. 17s. :{()1,
ilon-iiilril. ellc(
Mainnials, nerve eiidiiij^s in innsidi
lihres of. S!ll.
iVItinn's mi'tliod, 1^!),
cells of sensory nucleus of t ri-
i^emiiiiis. (!lv', 4t!l,
furrow. 100.
veil, 1(1(>.
Mast ical ion, development of muscles
(if, ill!), :>]>(».
Medial accessory lemniscus. (IKH, 4 4U,
column of motor coils. !'1.">.
;,'cniculate l)ody. see Corpus e;(>-
niculaliim mcdialc.
niicleii.sof corpus maininillarc, 7(18.
nucleus of thalamus. (i7!», 442.
ventral nuideiis of thalamus (von
Momdiow), OKI.
Mi'tliiili' iirri;s.si)riKc/ii' liihiih'l drr
Sr/i/cifi' (von Mecliterew), sco
Medial accessory lemniscus.
Medulla oi.loiifrata, :U)S :{li. :{|H
:{'-'4.
ohlonpita. lamellalion of, 177.
oliloiiLjiila, pyruini<liil tract lihres
in, !IS1.
sensory conduct
.iryri" 701.
spinalis. ',M)|.
ion pal h lo I'cnl ral
spin.ilis. commisMini
.'js;
spinalis, commissuiii dorsalis. ,'{()5,
;{!I0. 171.
■spinalis, coinmissui'a L'l'isea. !tS7.
us;
spinalis, cornii ilorsaM'. .ts<.
spiiiidis, cornu vciilralc, .'tS7, UiM),
17;{, (iOS.
spinalis, cornu veiilnvle. relation
to fasciculus loujfil iidiiuilis uw-
dialis, (117.
spinalis. niKdciis of posterior Imrii
of Waldeyer, I7:i.
siiitstantiti grisea of, Al^i.
Medullai'y groove. SS.
plale. Kiri. \V.\.
Mediillated nerve lihres. 1.
Medullatioii of iihr(
es. scipioncc ol
'Mi.
-J--
SUIUKCT INDKX.
1!()!>
Mi'issiicr's tactilo corpuscles, :!.'{?>,
•JIO, 2H. JI.V
Mercury, elVeds of, 2H7.
Mescllcepliitluti, ITi!), Sl>, Mii :|24.
Iiiiri/.diiliil sect inn lln'oiii^h, 427.
lowiT motiH' neiii'diies of, Itir).
motor luMirones in, !l(t!l.
Mesial liilet, see Leinniscns niediiil
Metaliolisni of neiii'ones, 'JI7.
Melanieres, 1115.
IS.
MelaliialM
niif
S».
Mela/DMiil nei've ti-iiiilis, '..*()!», l.'{,'»,
Melencc|.|ialon, I.V.), Si», ,'(12 .'tl<>.
pyramidal fibres in. St>, 1)H|, •)•)().
Meyiierl, laim'ie of, .><co Kasciciihis
rctrolle.Mis Meynerti.
commissiire of, sec; Commissiira
siipcriiir Meyiieiii.
Meyiierl's J'oti/diiti'ur/ii/r llimhcii-
krvuziini/, 772, VA'2.
Microsmal ic aiiiiiuils. 7I!>.
Midliraili, see MeselK'Cjilialiili.
Middle cereiiellar |
iiraeliiiim imnlis.
I'dunele. see
I'liial
HS.
decussation of tcf^fineiil nm. 77!i.
horn of lateral veiilri(de, see \'en-
Iriciilns lateralis, cormi inl'eriiis.
leinniscns, see liemiiisciis medialis.
or soft commissure, soo Miissa inter-
media.
Miftr/zc/lrnsniifcit, KH8.
Millhrv wei.sxe lj(t(ji\ see Strntum
album medium.
Mitral cells, r.:{',\ 7r)7, 4HI.
Moiio^tratilieil cells <if ihe r(>liiia,
:»(>.'{. 7h;;.
Motor area of cortex, !»7(J, iH»0.
axoiie, endinj^ in muscle
il.r.
mv :,;:{.
meilial and lali'i'al column
it!.').
cercoral nerves, c(
Mum of, 10-^2.
mtrol hy pal-
corlex, def.,'eneratioii follo\vin(.f (!X-
tirpalion of areas in, <)4(>-(iri4.
Motor ('ortex, extirpation of areas of,
Kt'i','. «4r».
libres from llie cortex, termination
of, !»H|.
function in cerehral cortex, locali-
zation of, Idt."!, iV.Vl <{.'{.-,. 1()()2.
localization in spinal cord, K!)j),
.'»,SU.
nerve spindle, .'»:{, {\{).
neurones, lower, HK!, r»77.
neurones of cervical cnlar;;emenl,
neurones of I lie <'ord, commissural
;,n'oup of. HH."), .■'»07.
neurones, ^'ronpin;; of, .SH}.
neurones of rliomhenceplialon, !>I5.
neurones of tlioraci<'. lumliai, ami
sacral cords, HH~.
neurones, relation of upper and
lower (von Monakovv), l(i;i(l.
neurones, np|ier and iiiteriiie(liale,
nuclei of luniliarenlart,'emenl,.')S(».
tclodciidrion of the froj;, r»7'».
leloileiidrion nf lacerla, r>74.
telodeiidrioii of the ralihil, >'f70.
telodendrion. relation to iieiirl-
leinimi, Nilfi.
Movemelils, hiliiterally (iiuervate(|
muscles, l()4(».
Miiller's fibres, «.',({, .Vl?.
Mnlli|iolar ;,'anj,'lioii cell, 4, li!>, '\i.
Muscles of (he eye, ililiervat ioli of,
Mnscle-se^nnelll, see .My(]t()ine.
Myeleiicephalon, I'lit, SJ>, .'{72.
.Myelin sheath. 41. Md.
Myelinizalioii of brachiiim cuiijuiic-
livuiii, (jr)7 (i.V.t, 4:{l.
Myocommata, 1!(H.
Myosepliim. HtH.
Myotome, li)."», l'_»«, liM), 201).
.Myotomes, profit ic; and post otic, 010,
relat ion of muscrles to coiihalic, !ll!(.
X. al)ducens,i»;i2,.'n:{,.r-'0-:{>24, ;{40.
41.-,.
I. 'I
I li
f i il
1110
TIIK NERVOUS SYSTEM.
X. iilidiRMMis acL-essorius, 1S<J, i'{()7,
32'i, 32S, .'UO, 374, !i27, 5»ri,
928.
Hc'usticus, see N. eoehleip and N.
veslil>iili.
imriculiiris iiiagiiiis, 1S(».
axillaris, 1,S«. 1S«.
(u( hleii'. :{07. 311, 312, 3«1. 3(5S-
370, r,4«, 413, 41«.
cutiuiL'us aiitiln-ac'liii lateralis, ls!>.
c'litaiiousaiitihracliii mi'ilialis. ISJK
C'litaneus hrat'liii (iorsali.s, ISIK
ciitaiiciis bracliii iiu'dialis, ISJK
cutancus colli, l,S(i.
cutaiieiis feiiioris lateralis. 100.
cutancus feiuoris posterior, 1.S7.
\*.)U.
dorsalis seajmlas 1S(».
facialis, 307. 312. 310-324. 340.
3(n,3(JS. 411. 417, !)3().
fciuoralis, 1S7.
glossopliaryngeiis, 307, 300-3 il,
320. 32 i, 320, 320, 340.377.
477.
glossopharyiigciis. lower motor
lU'iiroiu's of. !>2!*.
gliita'us inferior. lS7.
gluta'iis superior, 1.S7.
liypoj,'!<.ssus. 102. ISO. 300. 321-
324, 340,370,377.
iiypoglossus, in the embryo. 026.
ilioliypogastricus, 1S7. ISO.
ili((inguinalis. 1S7, 100.
interinedius, .514.
luiulioinguiiialis. 1S7, 100.
meilianiis, ISO, lsj».
niusculoculaneus. ISO.
ohturatoriiis, ls7. 100.
ticuloinolorius. 317. 323. 324.
340, 114 1, 1)4!).
opticus, T;f:{, TX2, T!)">. 507.
optii'us, coarse and (in(> fibres of,
785.
perona'iis comnuinis. Is7.
jierona'us supcrliciaiis, 100.
[ilireniciis, 1S(».
platitaris lateralis, 100.
plaiilaris medialis, 100.
X. abducens pudendus, 1S7.
radialis, ISO,
sajilienus, 100.
spermaticus extcrnus, 187, 190,
subclaviiis, 1S(».
suprascapularis, ISO.
Miralis. 100.
tlioracol)racliialis, 1(^0.
tibialis. 414.
trigeminus, 522, 307, 313-310,
32 1 -324, 340. 3S0,514, .')23, 5:51,
414. 915:5.
trigeminus, sensory paths of, 664.
Iroclilearis, 31 .'.-320, 340, 3S0,
001, 9158.
ulnaris, ISO, ISO.
vagus. 102. 307. 300-311, 320,
321. 32(5. 320, 330, 340. 477.
vagus, filjrcs from the terminal nu-
clei of. 728. 4<J4. 405.
vagus, lower motor neurones of,
929.
vest ibuli.. 307. 310-312. 31S-320,
324. 340. 301. 3(JS. 370. 410,
41 5, 410. 499. .lOO. .502. 510,511.
vestibuli. radix descendens, 407.
Xates, see CoUiculus superiv)r.
Nerve, auditory, see N. acusticus
and X^. cochlea^.
eighth, see X. acusticus.
eleventh, see N. accessorius.
fifth, see X. trigeminus.
first, see Xn. olfactorii.
fourth, see X. trochlearis.
ninth, see X. glossoiiliaryngeus.
second, see X. opticus.
seventh, see N. facialis.
sixth, see X. abducens.
spinal accessory, see X. accessorius.
tenth, see N. vagus.
third, see N. oculomotorius.
twelflh, see X. hypoglossu-s,
" Xerve-cell " of Ap.-ilhy, 52.
Xervc-endings, see Xenrones. bodily
peripheral centripetal, periplier-
al endings.
Xerve-roots, anterior see Hadix ven-
tral is.
SUaiECT INDEX.
nil
Nervc-rnots, posterior, see Iliulix dor-
salis.
spinal, see Nn. spinalos.
Nerves, sensory, see Neurones, peripli-
cral I'entripetul.
sensory, eiitaneous (Uslribiiliiin of,
ISH, 204, ;W0 ^4!).
Nervns trigeminus (portio minor),
422.
trij;cininus, radix dcscendens (mes-
encephalica). 422. <5(MK 'JiW.
trigeminus, sensory terminal nuclei
of, 641.
Neural tube, section through, 1)4, J>.'>.
J>(>.
segment, 11)5.
Ncin'ilemma, 41, 8fi.
Neuroblasts, 10. 44. 10!).
wandering of. 1T2.
Neurofibrils of Ajxithy. .'iS. .'»4, 14').
Neuroglia, proliferation in secondary
degeneration of white fibres, 228.
Nciiromere. 195.
Neurone. ;5!», 41.
am|)harkyoehrome, 118. 110.
apykiiumoriilious. 12;>, (»S. VtU, 71.
archiplasniic radiation. 148.
arkyoclirome, 67, 117. 131.
atti'uction splicrc, 148, S4.
auditory, lirst order, 880. 8;]9.
auditory, second order, 8Ii!).
auditory, third order, 8;i!).
axone hillock. 111, «4. S2.
axone. structure of. 143, 145.
axospongiur.i. 144. Si, S2.
bulbo-hypothalamit', ()!(4.
bulbo-mesi'ucephalic, 0!I4.
bulbo-|)ontal. ()!)4.
caryochniinc^. 115. 117. 133.
ceiitrosomc. 148-150. S4.
changes pniduced by ai'senic in.
1({{>, 172.
changes produced by fatigue in,
370,377. 1(54, HU5.
changes produced by injury to
dendrites of, 3:!i(.
changes |)roduced Ity ligature of
abdonunal aoi'ta in, 1 7;{.
Neurone, changes produced by mer-
cury in. 387.
changes produced by j)iiosphorus
in, 388, 1 70.
changes produced by |ioisons in,
383-388, 3!»5.
changes produced by section of ax-
one in (Nissl), 3:!;}. 284.
changes produced by section of ax-
one and of dorsal root in. 177.
changes produced l)y strychnine in,
385.
changes i)roduced by veratrin in,
38:5,171.
cln'omophile, 115, 123, 73.
clii'omphilic corpuscles, 110.
chroiuophobic. 133.
conception of. 40.
cytochronu". 115, 131.
cytoplasm, 147,
cytoreticulum, 143.
cytospongium, 147. S2.
dendrites of. see under Dendrites.
elementary spherules (Arndt).
104.
cnarchyoclirome, 118, 110, (»S.
endoplasm, 155.
exophisin. 155,
librillar theory of Schuitze. 102.
librilsof. 113, 130. 130, (J2.
ground substance of (unstaimible
substance of Nissl), nature of,
135-153.
ground substance, fibrils of, 108,
130, 140.
ground substance, honeycomb
structure, 138, 141, 147. 156.
ground substance, network, 130,
140. 7S.
gustatory. 535.
hccateromei'ic. 171,
lieteromeric. 171, KM.
hyaloplasm, 147.
hypothahunic. 004.
investment of, 150-153,
internal morphology of. 101, 157.
mesencephalic, (i04.
para|iyknomor])hous, 133, (»7.
{■ i
!
i
I l
Kl
1112
TIIK NKIIVOITS SYSTEM.
Npui'oiie, poriphonil auditory, .'544.
jMjriplionil wiitrifugiil, mil.
pcriplicral (ilfaelorv, ^t2[K
pigmeutiiry deposits, 107.
pyi<iu)in()rpli()us. 12;$, 70.
soinat-oL'liroiiii', IIT), 121, <»7, (JS.
spongioplasin, 147.
Staiiial)l(' substance of Nissl, see
under Tigroid.
stiehoehronie, 11 7. 121. 70, 71.
system. 1518.
system, ('ro>?sed gracilar nueleo-
cerebellar, 565.
system, uncrossed gnieilar nucleo-
cerelifllar, 5(»5.
tautomerie, 171.
tautomeric, classification of. CM.
tlircsliold {Winirotinc/iwel/c). 25:i.
unciainable substance of Nissl, see
under Neurone, ground sub-
stance.
visual, 5^3.
Neurones, bodily periplieral centrip-
etal, ;{5()-:{60. 204, 20(5, 207.
20s. 20». 210.
bodily periplieral (sentripetal. clas-
sification of. :!21-;i22.
bodily peripheral centripetal, pe-
ripheral endings. :i61-420. 211.
27».
bodily i.eriphci'al c(>nlripctal. pe-
ripheral endings. c(irnea. 214.
2I«. 217. 202. 400.
bodily peripheral centripetal, pe-
ri|ilieral cndii s, conjunctiva,
21s, 24J{, 2.i2.
bodily peripheral centripetal, pe-
ri|)heral endings, bill of duck,
222 224.
bodily peripheral centripetal, pe-
ripheral endings, bladdei-. 212.
bodily |)erii)heral centripetal, pe-
ripheral endings, ciliary body.
270.271.
bodily periphend centripetal, epi-
didymis. 2:{4.
bodily peripheral centripetal, gen-
ital tract, 250-201.
Neurones, bodily peripheral centri-
petal, hair. 225-22H.
bodily peripheral centripetal, kid-
ney. 27«.
bodily peripheral centripetal, liver,
2;{6.
bodily peripheral centripetal,
mamnuiry glands. 2S0.
bodily peri|iheral centripetal, mes-
entery, 254.
bodily peripheral centripetal, mus-
cle. 203, 20S, 272. 27S, 412,
421. 803, 573, 570.
bodily peripheral centripetal,
(esophagus, 211.
bodily iieripheral centripetal, pal-
ate, 213, 21 ». 223.
bodily peripheral centripetal,
I)r()state, 237.
bodily peripheral centri|)etal, sali-
vary glands, 233.
bodily peripheral centripetal, skin,
215, 242,244, 245,240.
bodily peripheral centripetal, cor-
puscles of Meissner in, 230, 240,
241.
bodily peripheral centri[ictal, Ruf-
fini, 247, 24S, 240, 250.
bodily peripheral cent ri]ietal. 7V(.s7-
zi'lh'ii (.Merkel). 22(), 221.
bodily peripheral centripetal, tu-
liuli seminifei'i. 235.
bodily peripheral centripetal, villi,
232.
lower motor. 41, 883, 577.
lower motor, lesion of. 103!).
lower motor, relation to upper
motor neurones, 1030.
lower motor, segmental arrange-
ment in cord, 884.
olfactory, groups of. 501 502.
Neuropil. 271-273.
Xeuropodien, 79.
Neuroporns. SH.
Neuros(mu's (Held), 50, 144, 145, 156,
HI, 82, 83.
Neurospongium (Mis). 106.
Neurotome, 1!)5.
^SA" I
SUBJECT INDKX.
1113
NissI bodies (stainiiblc substiinci').
105-1:54, see also Tigroid.
Nissl's classilicdtioti of cells. 115-126.
iiu'thod, 45. l()(i, -242. 2415.
Nil. cluiiiiini incdii, 1S7, 11MK
oeuloriiotorii, ilccussatioii of, 945,
olfactoi'ii. 754.
spinak's, description of, IS.), 323-
325.
si)iimles, gaiifjlia of, SCMJ.
spinalcs, radix dorsalis. 281. 5MM».
spinalcs, radix dorsalis. aseeiiding
limb of bifurcation. tUH. 4(iH.
spinalcs. radix dorsalis, collaterals.
»(>.-». 470-475.
spinalcs. radix dorsalis. collaterals.
elnssifieation of, 473-475.
spinalcs, radix dorsalis, descending
limb of l)ifurcation. !{(>+. 468.
spinalcs. radix dorsalis, fiijres of,
2«4, »(>S. 447, 465-460.
spinalcs, radix vcntralis, ;J0(».
spinalcs. rami of, \Ho.
subscapulares. 1S(».
supraclavii'ularcs. 1 SJ>.
Nolle of Hanvier, 32, 41.
Noyau 7Hosficafeur,svc Nucleus nio-
torius princejjs N. trigemini.
semilinidirc ile Flechsig, 674.
Nuclei arciformes, see Nuclei arcuati.
arcuati, »7(>. 5(i5. SOJ). 674.
cor|ioris mannnillaris, 76i), 400,
4))L
funiculi lateralis. ,'{S2, 402.
intcrmcdio-latoralcs. 013, 'jSo, 58(».
medialcs, 913, ,'>sr>, r>S({.
inotorii N. trigemini. 313, 033.
.")'.» 7, .>J)S.
of tlmlanuis, Nissl's study of, 676.
679.
nioiorii minores N. trigemini, 313,
933, r»{)7. .'lUS.
N. acnstici, s(^c Nuclei N. cochlea'
and Nuclei X. vestiiiuli.
N. cochlea", 310, 311. 312. 3lH.
323, 3(57, 372, 547, 549. 407.
410,411.415,418.
Nuclei (if <'enlral acoustic path. .■>55.
of cervical eidargenicnt, 014, ."iSo.
of luml)ar enlargement, r>.SO.
of the reticular zone. 677. (i70.
pontis. 3S0.
tcrminales nervi trigemini. Iihra>
arcuata> interna' from, 422.
Nucleus ala- cinerea-, 3(M>, 31s, 372,
377, 470, 4(K. 621-(i24.
and)iginis. 320. 407, 020.
amygdala'. 4({7.
amygdalil'ormis, .see Nucleus amyg-
dala-.
anterior thalami. 673. 443.
caudatu.s. 030. (i3S.
centralis inferior. 577. 322, 403,
40.-». 614.
centralis nu'dius. 577. 062.073.
centralis superior, 315.321,322,
3S(5, 579, 404, 405, 414, 420,
614.
cerebello-acusticus, 505, 511, 633.
coUicnli inferiori.s. 315, 380, 579,
H6H. 53{>.
colliculi inferioris. relation to lat-
eral lemniscus, 868.
commissui'a' postcrioris, see Nu-
cleus fasciculi longitudinalis
metlialis.
conniussuralis, 3(>8, 320. 487, 400,
410, 625. 626.
corporis gcuiculati lateralis. 814.
corporis trapezoidei, 300, 545-
547. 854. 857.
dentatus. 310. 308. 505, 302, 423,
424. 428.
dentatus, connection with cortex
of vermis. 424, 425.
dorsalis (Stillingi. Clarkii), 8, 474,
559. 576. 581-583. 387.
dorsalis. axones from, 740.
enibolifornus, 423, 424.
fasciculi longitudinalis medialis,
317. 380. 401. 415.
fasligii. 511. 568, 575. 413. 423,
424. 852.
fasligii. relation to Dciters" im-
cleus, 636.
-^««dSaaB»j»B«,-
11 u
TlIK NP^IJVors SYSTEM.
Ft
Nuclfiis riiiiiculi ciiiioati, :U»S. :tO!>,
»ls-:{2o. a;,-). :{,s-_», :{.s.->, .-):.<),
■)(;(», oCm, 40'i.
I'liiiiciili (•iincali.tcrminiitioiiof nx-
oncs from, 7^|.
riiniciili .jriicilis, ;»»s, .'{IS-.'WO,
.•{74.;{7.'>.;{s2-.'{,s4,rM!), SGO, 4(K{.
funiculi j^racilis. injury to, TOM.
funiculi ^niciiis, tcnniniitioii of ax-
onos from, 741.
funiculi Icrctis, 40.'{.
funiculi vcniralis, (114.
Klni)()sus, ilU'2. 4l»:{. 424.
luii)L'nula', 775, H;il.
hypo-llialamicu- (corpus Luysi),
:iSL». .-)(;<». ,-)M(). 071. ()7;j. 437.
impar, !(4;{.
innominatus (von Hcclitcrew), sec
Nucleus lateralis superior,
intercaiato of Staderini, 1)26.
lateralis anterior (Perlia), 944.
lateralis inferior, 577.
lateralis sujierior. 31 (J. 3*20-322,
57!». 4(M, 40.'>, 61(i, !)()!». i)7'2.
lateralis thaliimi. (57:!. 443.
leninisei lateralis. 314. 321, 322.
3(;?>. 3S2. 3S(J. 405. 420. S4(i.
lemnisci lateralis, ini'er'ior and su-
perior, Hill. S(i4.
lentiformis. odi*. 711. 71:5.
inaiiiiocellularis of medial nucleus,
081.
incdialis thalanii. IM'-). 443.
ininimns (von Hecliterew). 655.
inotorius prince|)s N. triujeniini.
313. 320. 407, 411, iwij. 507.
.')»S. mo. !):!5.
N. abducentis. 312. 31S. 31J>, 407.
411, 410. 427. !»;{•,>. 947.
N. cochleie dorsalis. S51.
N.cochlea> ventralis. H4H. r)41. .>43,
N. facialis. 21S. 312, 321, 322.
4(^7. 41«. o'Ml !»',".».
N. facialis, motor filires from me-
dial leninisc'iLs to, 1017.
N. Klossoiiliarynjjens. 377.
N. Iiypo;;lossi,"30». 31S-320. 32».
370.407, 411. :/.ni,im.
N'ucleus N. Iiyjiofrlossi, motor fibres
from me(lial leniiiiseus to, 1017.
N. oculomolorii, 317. 321-324,
407, 941, 94:5, 003, r»04, 947,
(>(Mi.
X. oculomolorii, collaterals from
fasciculus lonjj;itudinalis to, 7:21,
\. trochlearis, 31«, 321, 322, 324,
4()7.
X. trochlearis, collaterals from fas-
ciculus iongitudinalis medialis
to, 721, 400.
X. vestihuli, li'27.
X. vcstibidi lateralis (I)oiters), 312,
31S, .509, 5()H. 407, 411, 413,
410, 417, 41S.
X. vestil)idi lateralis (Deiters). (i:{4.
X. vestihuli lateralis, cells of, G;{4.
X. vestibuli latei-alis, crosseil cen-
tral vestibular jiatli, 6:57.
N. vestii)uli lateralis, direct cen-
tral vestibular path, 6:i7.
X. vestibuli lateralis, fibres of , 6:i7.
X. vcstibidi lateralis, path to cord
fioin. 41.'). 410, 41S, 410,420,
959.
X. vestibuli medialis. .310. 311,
3 IS. 3(»H. 507, 4(>7. 411, 410,
627.
X. vestibuli spinalis (radicis de-
scendenlis), 411, 627.
X'. vestibuli superior (von Meclite-
rew). 311. 312. 31S, 509, 407,
413.410, 41 s. (.:!().
of Darkschewitscli, 721. 724. 402,
4(;3.
of Deiters. see Nucleus X. vestibuli
lateralis,
of Kdiiifjcr and W'estphal, see Xu-
cleiis X. oculomotoi'ii.
of metamere. 197, 127.
of the middle line (Xissl). 077,
679.
olivaris accessorius dorsalis, 310,
377.
olivaris uocessorius medialis, 300,
310, :{2.{, 324, 370, 377.
SUHJECT INDEX.
1115
Nucleus oliviiris iiiffr'ior. 17fi, tH)U-
;{iL», ti'i'.K :{7«. .ITT. CIO.
olivaris supiTior, ;{!.'{, .'{S*2, .'{S({,
84:J, Ho], .•)44.
oliviiris sii|)iM-i()r, filiiv syslcni to
micleuif N.iit)(liicentis from, 422.
olivaris siipcfior, iicilimcle of, i*o2,
.'>4».
posterior Miahuni. 440.
pra-olivaris. 84:!. r>4.*S, H'u.
railicis (ifscciidt'iitis N, trij,'('iniiii.
s(>o Xiu'lci molorii iniiKiros X.
trigL'iniiii.
rcs])ii'atory. of ^lisslawsky, seo Nu-
cleus funiculi vent rails,
ret icularis tc<;nient i. ;{2*2, SHU, 570.
401. 4o:>, 420. 014.
ruber. .'{17, ;{24, 070.
niher, cross! ii^r tlescomling spinal
sysleui from, i»72.
semilunaris, 857, 858, .'i4», 843.
Iractus solitarii, ;J10. SIO, 4r!t.
48(5, (;24-G2(;.
Iractus spinalis \. tri<;:ciuini, .'{OS.
.'{(«>, ;{i.'{. .'{'2o-:{22, .'{4;{, ;{4«,
:{<:{, :{:.'>, 517, (54 1.
vent rails tlialauii. 44S{.
Y, .'{11. .'{IS, 507.
Nucl's space, :{(J4.
Niitrition theory (Golgi), 258.
Oheir Schleiffi, 688, (592.
Oherer Kern, (Burdaeii), 674.
Oriilonto/oriiixki'ni of Darksclic-
witscli, s(>e Nucl(Mis fasciciili
lougitudinalis nieilialis.
Oiiex, S72.
Occipital cortex, fibres from su])erior
collieulus to, 819.
cortex, lesions in, 817.
Oculomotor nerve, see Nn, oculomo-
torii.
Olfactory apparatus of the carp, 5(M).
bulb, see IJuHms olfactorius.
conduction jiatli. "cntral neurones
of. 748.
glomeruli, see (ilonu'rulus olfac-
torius.
Olfactory irranules, 750, 485.
islands, 701, 4S7. 4hs.
loiie. see liobus olfactorius.
nerves, see N. oll'actorii.
orgaiion.see Organon olfactoriuni.
tract, see Tractus olfactorius.
Olivary fascicidus, 954, 00!».
Olive, inferioi, see Nucleus olivaris
inferior,
superior, see Nucleus olivaris su-
perior.
Ol in- 1, Strang, 955, 00J>.
Operculum, .')(>4.
ophthalmic vesicle, 1 IS.
Optic chiasma, see Chiasma opti-
cuui.
uiM'vc, sec N. opt icus.
neurones of higher orders, 782.
paths, see Visual conduction paths,
radiation, s.r iiadiatio oecipito-
thalainica ((Jratloh'ti).
thalamus, see Thalaiuus.
tract, sec Tractus opticus.
Organon olfactoriuni, 188. 157.
s])irale (Corti). :{(J4.
Orang-outang, motor localization in
cerebral cortex of, 1000, <»:{.>.
Osnuitic animals, 749.
Pacinian corpuscles, 22.'{, 24.», 25.'{,
:{.'>4, ,'59;!. ;!94, ;S96.
Pain points, 25:5.
Pallium. SO.
extii'pation of motor areas in, 1023,
(»4:).
Pajiilla nervi optici, 784.
['ajiilla' vallata', 526.
Paracentral lolmle, see Lobulus para-
centralis.
Paraj.hasia, 1078.
Parapyknomoi'phous cells, 123, (»7.
Paraxone, 270.
l'ani.ri)H)'n, 90.
i'ars basilaris fasciculi [)edunculo-
niamniillaris. 772.
basilaris pontis, .'{l."».
niammillaris hypothalami, SO.
optica hyiiolhalami, SO.
V
V,
M
\
11 If.
TllK xNKIlVOUS SYSTKM.
I'jilli. I'l'iiiiliil (•(■i'cl)n)-ciirlii'c)|iiiiitMl.
(i('cij>ilu-t('in|M)nil (I'l'dii'ii-corlicii-
|M>iit:il. :ts(».
I'cduiiclc, iiil't'iiiir, sec Corpus rcsli-
foi'inc.
iiii<l(ll('. si'c Mnirliiiini |)iiiilis.
of (•(■li'lpniin, sec I'tMliiliciilus ccic-
bri.
of corpus ciillosiim. sec (iyrussiil)-
cilllosus.
of tliiiliiuius, si't' I'fduMculus lllill-
flllll.
superior, sec
Ilracliiuui conjuncti-
P(m1
viiin.
unculus ccrclit
( 'oi'pus I'csl iforuic,
Hi iuffWor. si'i'
cerebri, SU. :{S(}. !ts(t. i»H!).
ciTcl.ri, lociiliziilioM of filircs in.
(lloclic). KI'-'O.
.i-i.ori;; DKiuiuiillaris, jsee
Kas
uli pcduniMilo-Miaiuiiiillarcs. pars
basilaris.
eoi'poris caliosi, sec (iyriis sul)cal-
losus.
lloceuli. :nO. .'Ml, lUiS.
iiu'dius, see Hracliiiini ponlis.
superior, see Ifraeliiutu eonjuueti-
vuui.
Pediinciilussrlilfifi' (Fieelisiir), GM4.
J'eduiicMilus tiuilaini uiedialis. 444.
rehis. selerozoues of. I;{l l:{2.
Perforated sjiaee or laiuiuu, anterior,
see Sulislantia perforata an-
terioi'.
Perieapsuiar plexus, l\o.
Pericellular nelworii. ino.l.");}. s«, S7.
J'erikaryon, (>(>.
Perinuclear zone of Apalliy. i)Ci, ,'»{).
Peripheral ce fui^^al neurones, see
Neurone, .,.eripherai<'enlr'ifu,i;al.
nerves, components of, ))21.
Periiendicuiar fissure, external, see
Fissura parieto-occipitalis.
Pes lii)>poeainpi, ^ Hip])()canipns,
jiedunculi, see Jiasis pedunculi.
Phosphorus, ed'ecis of, '2M. 1 70.
Planum fil)rillare jirofundum, (J43.
I'lexiis l.rucliialis, 1S«. ;J2r).
cerviealis, IHH. Jl','").
cervieo-bnichialis. 1M(1, ;W5.
coccygeus, 1M7, li'-i-').
lumhalis, 1H7, li'-i").
lumbo-sacralis, |H7. II'^S.
|piidendus, IS7, 'oii't.
pudendo-eandalis. 1S7. S'^r).
sac
ralis. IK 7, ;«"j.
/'// ntitrhv, see (iyrus an),Mdaris,
PneumoL'iisiric nerve, see N. va>,Mis.
oisons, elTectS o
>f. 'JH-i-'^HS, •^>!»."».
Polioiuyelilis. spina! cord in, r)H4.
I'olyaxones, HI, 4'J. 4.'$.
Polymeric muscles, 201.
Polystratilied cells of retina, 1K,\.
i'ons (N'aroli), see Metencephaloii.
I'onliculus, 37'i, .'{77.
Posterior cereliral vesicle, HH.
loii;;itudiual bundle, see Fascicu-
lus lonj;i(udinaiis medialis.
nuclei of tliaiamus, CTH.
iijfaclory lolje, see Loiius olfactori-
us.
Post-mortem chan,<4'es in nerve cells,
Postotic myotomes, !(2().
I'ra'cuneus, Pi.iie 1, 4.
J'nfilor.'tiili'i LdnfiMiiidcL 720. !l(ii».
Precentral sulcus of cerelirum. sec
Sulcus pra'cent ralis.
Primary optic centres, Ti'T.
Primitive fibrils (Apathy). 272.
sej;ments, lit").
Processus ci'relielli ad cei't'brum
(Stilling). (mO, 4'_»S.
i'rojection libres. (!()").
Profit ic luyotouu's. i)10.
Prosencephalon. KJo.
I'roto]iljismic commissure, HitO, r>71.
conliiuiity, 7.
|)roeesses, see Dendrites.
Prozonal nerve trunks. 20!). VM\. 1:{H.
i'salterium. see ("oinmissura hippo-
campi.
Pulviiiar. r.;!(i, OHl. 440.
termination id' libres from. HIH.
tcrinination of <i|)tic libres in. ')13.
r '
SIMM IK T INDKX.
1117
1'iiiiI,IkiiIixI(i>i2 of licydi;;, '~»7:i.
l'ii|iil. rclli'N ((mtiiiclidii <il', m;!(I.
I'lirkiiijc, I'orpiisclcs or ci'lls til'. 1. \'2.
(i!». 7','. 75, 3S.
!'ylvii(nnor|>liiiiis cells, Vi'.i, 70.
Pyriiinidiil ImukIIcs, set- Fasciculi
cL-rclu'D-spiiiiilcs.
cflls. r,', (is, ('.!», 75, SS, :{7, !I7(!,
((LM).
tiaci.scc l''asciciilicci'clini-spiimlcs.
rynimids, nntcrior. sec I'yiainis (me-
dulla' (il)li)iipila').
(lecussatiiiii of, see Decu.-salio py-
rainiduin.
I'yraniis (ineilulla' (ilil(>ii;,'ata'). .'U>S-
31'i, ;{«s, :{7:», imm).
Quadrice|is leiiKH'is muscle, nucleus
(if, !»05, :>s;{.
Qiiiidi'ijjeuiiual liodies, see Coi'poni
quadrigemiiia.
Radial io lorpdris callosi, 1054.
(icci pile 1-1 lialaiuica (tii'alioleti), H14,
H'2-2, s-s.i, :ti2. :ti'.i.
(icci[iit()-t lialamica (( i lat iolel i). end-
ing of libres of, s-2-,>. H',>:',, .^'Js.
Kudic'os nervorum eereliraliuui, see
corresponding nerves.
I{adix descendeus (moscncopbalica)
N. trigeniini. see N. trigemi-
inis.
dorsalis, 5.5i). l{»4-5!(>0, :!:!:{. :541.
(lorsalis, developmenl of. IHl.
postei'ior. see [\adix (lorsalis.
ventral is. .SK5.
lidiiilschlilir of His. see Marginal
veil.
Uundzellen of sensory nucleus of tri-
geminus. 042.
lidii/cnliirn. see Uliombelicepliah)!!.
React idii at a distance, '")7.
Recessus geuiculi, JM).
• infundiliuli, *M).
mammillaris, JM).
utriculi, 8<»1.
Rectus abdominis, nerve endings in.
8i)4.
i!ed nucleus, see Nucleus ruber.
Regeneration of nerve iibres, '245.
Regio subthiilamicii, see llypothala-
nnis.
sul>tbalaunca, layers of, ti7i.
{{eil. island of, see liisida.
Resiiform body, see Corpus resli-
forme.
Reticular forunition, see Fornuitio
reticidaris.
Zone, nuclei of, (177.
iielina, a.'»7. :{.'»S. '.UM).
IliliiuKiiitliiil of corpus geiiiculatuin
liiterale, 7!K
lietina, bipolar cells of. 5|:i.
comjiarison with other sense or-
gans, 541.
ganglion cells of, 7^1!.
liiyers of. 5;i:i. 7(S4, .'»'_'{).
origin of, 1!S7.
rods and cones of, 5:(5.
Retraction theory, 1(K».
Rhineiieephalon, 74H.
divisions of, 751, 754.
Uhoudiencephalon, lower motor neu-
rones of, i)15.
Ricin poisoning, '•2!t7, 15JJ.
h'ii'scii/ii/i(tiiiiilcii:rll(ii (Ret/), 078,
Rolando, fissure of, see Sidcus cen-
tralis Rolando,
substantia gelatinosa of. see Nu-
elcns tractus sjiinalis nervi tri-
geniini.
Roller's nucleus, !)2().
loiof, ganglion of. se(> Nucleus fas-
tigii.
Roots of spinal nerves, see Radix
ventralis, Radix dorsalis.
of spinal nerves, groups of fibres in,
!»01.
Rostrum corporis callosi, 1051!.
h'liban dc IhiU ^ee Lemniscus.
corficdl, see Cortical lemiusciis.
iiifericnr, see I,euiniscus lateralis.
sujwrU'ur, (i80. (W'i.
Ruflini, nerve endings of, 'HiS, 247,
24{>, 250.
v\
n
%
V
\(
^
ins
TIIK Ni;i{V()(S SYSTMM.
I i
1
Siicnil nucleus, si'c Nucleus ilnisulis.
Siirtoriiis muscle, nerve emlin^js in,
HIM.
Sciilii tynipani. 'U>2.
vcstihnli. M'2.
S<'ai'|iii's K'H'K'I'"'". ■■<'''' ("iinfjlidu ves-
tibulan>.
Srlidlciifiiniiii/tr h'iirpiT (von
'I'.schiscli), «74.
St'hnllzi'llin (von iMouakow). KCiO.
Sdiizaxones, H2, 40.
Schleift!. .sen lieninisciis.
Schleiff aiiH tiem oln'rcn Zwcthi'iyel,
4:1.-,.
Schull/.e'scoinnui.lilMJ. :J{>,"»-2yH, 44H-
4.'51. 454-47.').
Scisst.rs of the brain (Stilling), 42H.
Sclerotome, l!)<). 1*^7.
Sderozone. "JOH.
Secondary def^eueratioii, .see Degen-
eration, Wallvrian.
degeneration in i)\raniidal tract,
lOUI. <54I.
degeneration of motor fibres after
cerebral lesion. <>43.
Segmentation of body. 1!):!.
Segments of spinal cord, function of,
!)0a.
Si'/is/thiirfiKUif/ifil of corpus genicii-
latuni laterale, 7!)8.
Seitenliuie, see Jjuteral line.
SeifUehi' f/reiizficfn'cht der (/rniieit
Siihsfdtiz.sw Fasciculus lateralis
limitans.
Semi-decussation in optic chiasm.
786.
Sense centres, cortical, lesions of.
1074.
Sensory components of cerel)ral
nerves. i(24. .'»{>•_>.
conduction pal lis to central gyri.
704.
conduction paths to cortex, 7i{4.
cutaneous areas, ;i;{0-:{4l», 188, 189,
i5>o-i»r>.
culane<jus area.s (aiiii'sthesia), 201.
cutaneous areas (pain), 1{>7, 198,
199, 200.
Sensory ganglia, see Oanglia, sensory,
nerve lilires, development of, 181,
inicleiis of .\. trigendnus. 042.
optic centres. 7i*7.
iystcms. !. II, 111 of Klechsig, 785,
4«({-4«8.
.Septo-nmrginal iaindle of Mruce and
.Muir, see Trimit/le mfdiiiii of
(iombaidt et Philippe.
.Septum pellucidiMn. I'late I. .'t.
Sheath of llenle, H(».
Side fibrils, 12,41, iW, .'>7. 8i)2.
Silent areas of cerebral cortex, 1071.
.Small-celled hyjioglossal nucleus of
Holler. \m\.
Sail If It .s (( hstan z, 574.
Solitary binidle, see Tractus sf.lita-
rius.
.Somu'sthetii' area of the cortex, (567.
conduction path, rimtnie of, 731),
409-471.
path to cerebrum l)y cerebellum,
(147.
Sonuitic t'omponeuts of peripheral
nerves, {)2\.
Sonuitofhrouie cells. 11."), 121,07,08.
Somatoplasm, 'tli, 55.
Somites, 88.
Space, |)erfoi'ated, anterior, see Stib-
stantia perforata anterior.
Special senses, I'cntres for, see Sense
centres.
Specific energy, 2.')4. 2.').5.
Spinal ac<'essory nerve, see N. acces-
sorius.
coril. bulb or uuirrow, see Medulla
s|)inalis.
cord, motor localization in, 899.
nci-ves. see Nn. sjiinales.
neurone system from formatio re-
ticularis, 962.
roots, groups of fibres in, 901.
Spoiigiol)lasts. 106, 99. T);}?.
Stereognostic sense, 1077.
Slichochrome cells, 117, 121, 70, 71.
Slid (les wciliolen Knichikkers, 875.
Sti-ato biancocinereo profundo, 809.
biancocinere./ superticiale, 809.
/"-
srn.IK{T INDKX.
in
Slialiiiii iilhiiiii tiicdjiiin, HDjI.
iill)uiii |ii'(iriiiiiliiiii, HO!),
('iilcitriiiiiin, ll).")!).
KloliHTiildsiiiii (iT olfactory l)ull),
?.*),■), 47 s.
f;risciim cciiiriili'. .'{15-317, ill*,)-
324, 3M«, r,T!», HOii, ,s;)i.
KiiM'uiii (Milliciili sii|)(ii(.ris, 800.
HflH, 'trt't-ooH.
),'risiMmiofolt'acton Imlli. 75.'), 47S.
griscimi |iroriiiiiluiii. H(»!), ,'»1H.
iiHcroliviHv ' lciiiiiis<i. 300-312,
321-324. 370. -,().{. rm. 402,
41(5,422.
inoli'ciilare sen f,'i'latiiiosiiiii, I'h}.
47H.
propriiim ciiiici. lOOl.
S(i</iffii/<' r.i/i'nnnn, seo FHSciciiliis
loiij,'itii(linalis iiitVrior.
siii/if/(t/i' intern (^/// (Sachs), 8 1 ,"), Ttli).
zonalc colliciili su|ii'i'i(>ris, H()8, 809.
Stria iiic'diillaiis, 774.
tncdnllai'is tlialaiiii. rclatimi to lii|)-
pocaiiipus ami liasal Lraiifjlia, 774,
407.
olfa<'toria lateralis. 7.")(). 7.')<».
olfactoria mcilialis. V.\S.
Stria' iicustica'. see Stfia- nicdiiljarcs.
iiifdidliires (simi aciistic;i'). 3<55).
372, r>3(J, .'>4o, r)r);}, 840.
Stripe ot Vic(id'Azyr, ({3S.
Strychiiiiio, cITecfs of, 28.").
Siilicdiiscioiis iiiipidscs. '^oO.
Suhstaiitiii alba of cord, stinuiiatioii
of. C40.
gelat iiiosa. .300, 300, 403, 41 7, 41!>,
4,(», 041.
gclatiiiusa eoiitralis, 373.
gelat iiiosa (Uolaiidi). sec Nucleus
tnictiis spinalis ncrvi trigeiiiini.
grise.1, 40.>, 414, 410, 473.
nigra, 31<», 317. 3.S0, r)7!».
nigra, termination of tlninih fibres
in, 1028.
perforata anterior. .')0(K ■
Snbtlialaniic tegmental region. s,>e
Tegnie-ituni and llypotlialamiis.
Sulci temporales transversi, (538.
Sulcus centralis dJolandi). (5.33.
eiiiguli. 02.
eingidi. pars nuirginulis, 02.
cinguli, pars subfronlalis, 02.
frontalis inferior, (538.
frontalis superior, 03H.
Iiypollialainicus (Monroi). 0(K
parolfjieloriiis posterior, ~,M.
pra'cent rails. 033.
riiinencepliali inferior, 7t'>3, 47(1,
477.
semilunaris. 7.')2.
spiralis. 3(52.
subpariclalis. 02.
temporalis superior. (538.
Superficial arched fibres, sec Kibra-
arcuala' externa',
opiio path, 821.
Superior coUiculus, see f'ollieulus
superior,
lemniscus, ()88. (i!»2.
medullary velum, see Velum med-
ull.'ire anierius.
(dive, see Nucleus olivaris superior,
olivary complex. 84:?.
Supranuirgiual gyrus, see (iyrus
suprainarginalis.
Sylvian aqueduct, see Aquediictus
cerebri,
fissure. see i-'issura cerebri lateralis,
fossa, sec I''ossa cereliri lateralis.
Sympathetic ganglia, 1!>0.
Sympatliieus. ,330.
Si/n<ipsis. HO.
Si/stcnui Icnini.sni/r nii/rhnrcjihalo-
dienci'phaliciun. 701.
/cninixrti/i' niyeleucep/i<i/()-p(illi((Ie,
714.
nii/i'/finrep/Hi/ii-ri'ri'/ii'lltn-i' rrurin-
fiini, 741,
in>/f/t'nc('/i/i(i/i>-r('rfl)i'!/are non-eru-
cidfinn. 741.
inPiintnicinii) (liinri'phdlo-pnlUn.
turn. 701.
(ni'xi-on iciin, ) mycli'iivcpliii Ui-pnUi-
olc. 701.
{neuron iriini) nnjelenceplid/o-fhn-
Unnieum, 714.
! ►
ll-ja
TIIK NKIlVol'S SYSTKM.
Sj/x/i-mii {iifiinniiriiiii) .ijn'iio • ri-ir- 'I'lirchholil of ImIhikI, sen Ijtiii'ii in.
Iwlliiri' mi/ni/ii/irn/r nuijiiiir/i- siilii'.
'•'(/'■, 'Ml vahir, •,>.",;!.
(ni'iinininiiin ■•'/iin<i-//iii/iiiiiiriim 'I'liiimli iiii'ii, pyritiiiiiliil IHu'cs froiii,
rni/ni-ldtf'ni/r.mi). \ Kl.'iO.
(iivuriiiilrinii) /^/liiiii-i/iiinlni/iiiii- Ti),'i'"i<l. ■>•"•. 17, KKl. lOS, 1||, 112,
Hwm ri ii/m-lii/rrdli' sii/im'iix,
500.
TubcH, (Icgcncraticiiis in, !24H.a-14, 254,
42H, 4:i«.
Tn'iiia cliorioiilfii, 774, 45Mt.
tiialiiiiii, 774, 4JM5.
'I'api'liiin. .'>22, 5'_»:{, 10r)4, 1007.
'rasli'-lnuls, si'c ('iilyciili ;,Mistiili)rii,
Titxtzi'lli'iinntX '/'ii.s/iiiriii.-<n\>( Mcrkol,
Hi) t!2l.
'I'aiitniiicric iiciii'niics, sec NiMiroiics,
taiitiiiiit'ric.
'I'pgiiu'iital Imiiillt' i>f Iciiliforin iiii-
clt'iis, 074.
Ijundle <if red nucleus, (i74.
I)unill(' i>( tlialanius, (i74.
prujcciiiin, {M).
'J'cgnu'nluni, dccussalicins of, 773,
492.
paths U), 6($H.
Telencephalon, lo!). S{>.
motor ni'uroiics of, !l7o.
'IVloileniirion. 41. S',>.
Telodoiidrions of inot(jr axone, HOS,
574.
Temporal ccrcln'o-corl icoponlal path,
1045, 104u.
pyri, auditory fihre.'i cndinuf in, 878.
Tempora/c (irons/i ini rinili- liri'ivkcii-
bahn, .«ec Temporal cerebro-cor-
ti<'opontal pat)
liii'cltHjihiirv {V 7.')f(.
Testes, see C'"'' vrior.
Tctanus-t' ., of. I, SI. 1Si2, |
303.
Thalamus, ^...
l)undl(^ fi'om nucleus rulier to, 42H
nucleus of, 073. (170, 078, 07!).
ventro-lateral nuclei of. 569,
T/hifnnnisiiiaasir (Tschcrmak), 682.
127, I2)», 1!10, i:<2, i:}4, 155. l.-ifj,
((4. ((.'>. 7.'>. ;».
Tongue, origin of muscles of, ,')JM,
1)20.
Touch points, 25:t,
1 ract or tracts, antcro-laterai ascend-
ing, see Faseicnlus ventro-hitc-
ralis.
Tract, comma, see ( 'ommaof Scliultzo
and Schult/e's coiuiiui.
crossed or lateral pyranddal. see
I'"asciculus cerchro-spinalis late-
ralis.
direct cerelicllar, see Fasciculus
spiiio-cercliellaris dorso- lateral is.
direct pyranddal, see Faseieidus
cereliro-spinalis veniralis.
of liiirdacli, see Fasciculus cuneii-
tus,
of lillct. see Lemniscus.
of (lowers, see I'''as<'icuius cerehro-
spimiles suiierlh ialis.
of (ioll, see Fasciculus gracilis.
of liissancr see l*'asciculus dorso-
latcialis Lissaueri.
oll'actcry, see Tractus olfaclorius.
optic, see Tractus opticus.
pyramidal, see Fasciculi cerehro-
spinales.
Tractus oi)ticus. 7!H!, .»09. 798.
olfactoi'ius lateralis. 47M.
olfaclorius medialis, 47.H.
pe(lunculaiis trausvei'sus, 807.
solilHiius, 102, :{09.:U2,:ms-:{20,
.•12(J, .'{27. :{7«. 48.5, 407. 020.
spinalis X. trigemini, SON, .'{09,
311, 320-:{22, 329. 34(>, 377,
391. 392, 407. 411-413, 41«,
417.419.421.422.
tegnu'nto-ccrcbellaris (Fdinger),
664.
Thnlamusschale (Tschermak), 682. j Tra{>e7.ium, sec Corpus trapezoideum.
HUh.lK(T INDKX.
I -J I
I
Trii|ic/ui(|iil liody, SCO ('(ir|iiis trapf
/oiiliMiiii.
Tri)m;,'iiliir piitli uf llflwcfr. !l.>J.
Triiiiifilf ni('ili(in of (Idmliimll el
I'liilippc, .t.VJ-.|r)7.
Tiicc|is rriiisclr, iici'vi' t'!i(liii^;s in, N))4
Trip'inimil irtvc. st'c N. Irii^ciiiimi.s
iidiroiicM, (Ttitnil ci'iiliiiiiliil. (HI.
Ttip'iniiMis. film's to r.inimlio \v\U;-
uliiris fnirii ti'i-r>iiiiiil nucleus of,
Ti>H. 4«4. 4«J.V
Tri",'(inuni Icninisci. ((Hd, H47.
Trochlciir nerve, see N. tmclilearis.
Trophic centres, 'l'H\.
Tro|iliicity. theories of. :i()ti ;|||.
Tiiincus corporis callosi, K).");!.
Trunk iireii of motor cortex, !»!)!», (}(}.*{.
Tiilier cinereiini, \){).
Tuliercle, acoustic, see Nucleus N.
C()(;hica' (lorsalis.
cuneate,seeTulierculuincuneatuni.
1)1" optic thalamus, anterior, sue
Nucleus anterior thalaini.
ol' optic thalamus, [losterior, see
I'uh inar.
TiiliciriilcH </ilii//ii/iiiiii'ilii.r, see ( 'or-
l)oni (iiiailrinemiiia.
Tuberculuni ciinealuni. 5(10.
hiterale s. acusticuni, see Xucleus
X. ccH'hlea' (lorsalis.
Tunnel cord, 3(54.
space, Sm.
Tiiruk, column of, see Pnscieulus
cerebrospinalis ventralis.
TUrc'k's degeneration, 225,
Uncinate fasciculus, see Fasciculus
unciiuitiis.
ijyrus. see Tiicus.
l^u'us, Plate I, 4.
connection of Iiippocainpus witli.
4.SJK
tenniuation of lihers of striaoifac-
toria in, 7oi).
Unipolar cells, tUi. 113, 114.
Up|)er face centre, !)!I7.
facial nerve, 9;U).
motor neurones, 0.52.
- ' rpper motor neurones, rehilinn to
li)Uer motor neuroiie.-, KCtd.
I motor neurones, lesion of, l();!i».
1 r/(/('m'///c//V'. see I.emiiixus lateralis,
f'/m/ ///(■///(■, 111,*).
, l'ririr/)r//:rni, \<>7.
I'triculus, .'Mn.
I Vapil nucleus, see Xucleus aKc cin-
erea-.
I V'ajfus nerve, see N. vagus.
I Vallate pajiilla', see Papilla- valiatu'.
J Valve of N'icussens, see Velum medul-
lare aiiterius.
Vascular segment, 11(0.
' Vater, corpuscles of, see I'acinian
ccirpuscles.
X'elum medullare anterius, ;172,
medullai'y, superior, see Velum
nu'<lullare anterius.
Ventral horn, see Columna grisea
ventralis.
; horn cells of cervicid cord. i)05,
ri7s-.-,s'_».
nucleus (d' lateial genicidate hoilv,
fl7i».
I nucleus of the sixth nerve, !);{2.
nuclei of thalamus, (!7H. (i80, (i81.
tegmental decussidion, see Decus-
j satio tegmenti ventralis.
I Ventricle, fourth, see Ventriculus
I quart us.
Vcidricles. lateral, see VeiMriculus
lateralis,
of l)rain. see Ventriculus lateralis
el <|uurt us.
Ventriculus lateralis, <},'»1, (;.->.'{.
quart us, ;{()». 31 s, 372.
Ventro-laterai cell-group of anterior
horn, see Neurones, lower motor,
lateral tract, ascending, see Fas-
ciculus ventro-hiteralis superfi-
cialis.
Veratrin, effects of, 28;3, 171.
Vermiform process, see Vennis.
Vernus, oOH. ,')7.').
connection of nuclei of roof with,
424, 425.
1122
TlIK XEKVors SVSTKM.
I) '
\.st,lM,Io-s|,inal pathj>r,!». , WalUTinn .legonemtion, see Deiren-
\ le-i i|-A/,vr. huii.lle ,.f. see Fasei.Mi- { eiatio,,. .ee-mdarv or \Vall..,ian
lus Ihalaino-inainmiilaris (Vie.| i il„etri..e and il,e neuroiie-eoiiccMt"
(1 Azyr). 22V).
Villi, choroidal, see IMexus eliorioi- i Warm points. 2'}:i.
''i'"^- ; Wernicke's field. H14.
\ iseeral motor and sensory oonipo- I liendanopie pupillary sign, 882.
neiitsof periplieral nerves. !)21. | Wliite eolunins of cord, see Kiinic-
Visiial area of cortex cerebri, lesions i uli.
of. 817.
centres. contieclioH with cord and
bulb.see Visual coiidiiction paths,
conduction pat lis, o'lU. .VJ'i, ."j.'J'J.
commissure of cord, sec Commis-
suia alba,
matter of ceroliral hemispheres, see
'. 'entnim semiovale.
Worm, see N'ermis.
conduction path' ^ntrifugal fibres
"•"■ ^•^~- Zvrt^t rente arre.ssonsr/ie liundel ^von
Jk'chterew). ()84.
Zona incorta, 671, G73. 437.
reticularis (Gitlerschiehl), 438,
conduction paths, decussation in.
.'.30.
liirection. cortical area for, i)!»8,
sense area, primarv. 8*,>L', X'i'i.
N'ital staining, see Khrlich's vital
staining.
Vurderdraiiyretst, 374.
G77.
Zone F (Munk). removal of, (;!)7.
Zone inotriee (Charcot ). !(7,').
of confusion, KD;""), (»32.
L
I
w
T
i