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 GUDDEN'S ATROPHY METHOD: AND A 
 '^ SUMMARY OF ITS RESULTS 
 
 BY 
 
 E. C.i^GUIN, M.D. 
 
 COXRESrONUING MEMBER OF THE " VEREIN FUR INNERE MBDICIN " OP BERLIN 
 
 [Reprinted from the Archives of Medicine, Vol. x, Nos. 2 and 3, 1883] 
 
 G. P. PUTNAM'S SONS 
 
 NEW YORK : 27 & 29 WEST 23D STREET 
 LONDON : 25 HENRIETTA STREET, COVENT GARDEN 
 
 1883 
 
 ^
 
 T^AilT 
 
 GUDDEN'S ATROPHY METHOD: AND A SUM- 
 MARY OF ITS RESULTS. 
 
 By E. C. SEGUIN, M.D. 
 
 MUCH as we honor the discoverer of a new fact of 
 importance or of a series of facts, we owe much 
 more to him who places at our disposal a new method, one 
 sufficiently tried to merit adoption at our hands. A method 
 is a chapter of applied logic, pregnant with possible results 
 of unknown importance. And this is not its only value, 
 for, as a part of the logic of science, it also serves a purpose 
 in scientific speculation, and almost inevitably gives rise 
 to new ideas, to other methods, by analogy or by deduction. 
 
 Gudden's atrophy method, one of the anatomical 
 methods applied to the study of that obscure field of re- 
 search — the central nervous system, — lay hidden, most un- 
 fortunately, in the possession of its originator and a few 
 pupils, for nearly thirty years, and even since its publica- 
 tion in 1872, it has been but little noticed outside of a very 
 small circle of neurologists.' Yet, I think that the follow- 
 ing abstract will show it to be one of the most important 
 and promising of the various special anatomical methods.* 
 
 From 1850 to 1852 Augustus Waller was at work in 
 Budge's laboratory at Bonn, perfecting his method of study- 
 ing the degeneration of severed nerves. The facts of de- 
 generation and regeneration after nerve-section had been 
 long known, but it remained for Waller to formulate the 
 
 * In the most recent scientific work on anatomy (Burt G. Wilder and Gage, 
 "Anatomical Technology," New York, 18S2), containing a remarkably full 
 'bibliographical index, the name of Gudden does not appear. 
 
 " The special anatomical methods applied to the study of the central nervous 
 
 Reprinted from the Archives of Medicine, Vol. x, No. 2, October, 1883.
 
 2 GUDDEN'S ATROPHY METHOD. 
 
 law under which the degenerative process occurs. In his 
 '' Noiivelle m^thode anatomique,'' Bonn, 1852, he gave a 
 full summary of the facts and laws he had discovered, and 
 they have been common property ever since, leading to 
 numerous important anatomical and pathological discover- 
 ies. The doctrine of the Wallerian degeneration, has, I 
 may say, been a valuable instrument in our hands for thirty 
 years. 
 
 At the very same time, 1849, Gudden, a recent graduate 
 of the University of Berlin, then assistant physician in the 
 Siegburg insane asylum under the celebrated Jacobi,was ex- 
 perimenting upon the brains of animals in a different, yet 
 correlative, manner. He had already extirpated eyes of 
 rabbits, and noted the atrophy of the intracranial optic ap- 
 paratus; he already knew the tractus peduncularis trans- 
 versus, and many of his subsequent discoveries were half 
 developed.* This was done in ignorance of Waller's work, 
 and partly before it ; certainly long before Tiirck's publica- 
 tions on secondary degenerations. 
 
 For reasons best known to himself. Professor von Gud- 
 den did not publish an account of his method until 1870,^ 
 although his principal facts and laws had long been known 
 to him, and he had communicated freely with friends and 
 assistants, so that we have here a striking example of the 
 simultaneous discovery of facts, laws, and methods which, 
 applied to the same division of the animal frame, are in 
 themselves not very unlike, and in their results are logically 
 united, and, indeed, complementary to each other. 
 
 system are : (a), The dissociation or dissection of fasciculi in partially hardened 
 specimens, as practised by older anatomists, by Foville, Gratiolet, Broadbent, 
 and many others (nearly disused); (b), the Rolando-Stilling method of series of 
 fine sections of the hardened organs ; (c), the Wallerian degeneration in ani- 
 mals ; (d), the Tiirck secondary degenerations in man (and in animals); (e), 
 Flechsig's method of determining the period at which certain systems of fibres 
 in the foetus acquire myelin. 
 
 ' Oral communication from Prof. v. Gudden, August 4, 1883. 
 
 ^ Experimentaluntersuchungen iiber das peripherische und centrale Nerven- 
 system. WesphaFs Archiv, Bd. ii, p. 693.
 
 E. C. SEGUIN. 3 
 
 I purpose in the following pages to enunciate the central 
 principle of Gudden's method, and then to analyze his pub- 
 lications and those of his pupils, more or less in chrono- 
 logical order with reference to publication. Besides con- 
 sulting these publications, I have had the advantages of 
 conversing with Prof. Gudden and several of his pupils, 
 and of examining the specimens proving the statements 
 advanced in nearly every case. 
 
 Principle : TJiat by experimenting on neivly-born animals, 
 especially those zvhich, like the rabbit, are brought forth in a 
 sometvJiat fcetal state, complete atrophy of the central connec- 
 tions of a nerve-trunk, or a nerve-fasciculus, or a nerve- 
 centre, is obtained by operation. The central {proximal) 
 fibres and cells are destroyed, ivJiile the peripheral fibres, if 
 any, undergo the Wallerian degeneration. 
 
 There are several secondary advantages in using very 
 young animals; they (rabbits at least) have almost no hair; 
 they suffer but little pain, and scarcely struggle under the 
 knife ; they bear the shock of incision and removal of 
 important parts of the central nervous system wonderfully 
 well ; haemostasis is in them very rapid and definite, and 
 the process of repair simple. 
 
 For operations on nerve-trunks, almost any animal can 
 be used. For experiments on intracranial parts, dogs are 
 objectionable because of their hard craniums ; kittens are 
 intermediate between rabbits and dogs in this respect, but 
 they are liable to suppuration, and the mother is apt to 
 interfere with the sutures. 
 
 Most operations should be done on the second or third 
 day of life, but may succeed later; still, the older the 
 animal the more the Wallerian law of degeneration in one 
 direction (centrifugal from centre) only prevails. 
 
 For most operations on the olfactory apparatus it is
 
 4 GUDDEN'S ATROPHY METHOD. 
 
 necessary to wait until the animal (rabbit) be six or seven 
 days old, in order to give time for the ears (hearing and 
 tactile sense) to develop sufficiently to enable the creature 
 to guide itself and find the mother. 
 
 For operations on the hypoglossal and vagus nerves 
 one must wait still longer, from the second to the sixth 
 week/ 
 
 The various operative procedures will be described under 
 the several heads of this review, but it is well to state here 
 that the lesion should be a destructive one ; the olfactory 
 lobe or eyeball must be removed, or in the case of nerves, 
 their central ends after section must be pulled out of their 
 bony canals with good forceps. In the case of nerves in 
 newly-born animals, so much comes away by this method 
 that there is reason to believe that some axis-cylinders are 
 broken off deep in the nervous centre from which they 
 spring. 
 
 It is possible that some of Gudden's operations give 
 results as much by degeneration as by simple atrophy ; in 
 other words, that his and Waller's method overlap each 
 other. In this connection let me say that the histology of 
 the early period of Gudden's atrophy is unknown, which is 
 a deplorable hiatus in our knowledge. From a study of 
 this point we may learn something of the obscure point 
 referred to, viz., the true relation between the two methods, 
 and obtain new light on so-called " trophic " laws of the 
 nervous system. 
 
 The operated animals are left to the mother's care, and 
 allowed to grow from six to twelve weeks ; , the former 
 period being quite sufficient for most experiments. Indeed, 
 Gudden has shown ^ that after removal of one eyeball in 
 dogs one day old, distinct atrophy of the optic nerve was 
 
 ' Oral communication from Prof. v. Gudden. 
 
 ' Archiv f. Ophthalmologic, Bd. xxv, Heft 4, pp. 237-246, 1879.
 
 E. C. SEGUIN. 5 
 
 visible on the 8th, 14th, and 28th days. In rabbits a dis- 
 tinct atrophy may be visible in 36 hours after operation on 
 second day/ 
 
 During this period of preservation, the animals should 
 be carefully studied as to their functions, with especial 
 reference to the injured apparatus, and compensatory func- 
 tions. By doing this in as careful a manner as Munk has 
 done for his cortex experiments, some physiological and 
 psychological knowledge might be gained from each series 
 of operations. This has been done, but not as fully or 
 exactly as should be. 
 
 After the animals are sacrificed, the affected parts should 
 be carefully examined for asymmetry, change in color and 
 consistence. If possible, photographs of the fresh speci- 
 mens should be taken, and careful measurements of parts 
 made. The organs are then placed in a solution of 
 bichromate of potassium, or of osmic acid, for hardening. 
 When this is complete the various sections necessary to 
 reveal the direction and extent of central changes are made 
 and preserved in accordance with well-known methods. It 
 is often desirable to have complete series of sections 
 through the whole organ or a portion of it, so as to enable 
 the exact extent and distribution of the atrophy to be fol- 
 lowed. In such cases the use of Gudden's microtome is 
 necessary. The sections should be thin enough to allow of 
 their examination by |- or -|- inch objectives. Usually trans- 
 sections show the lesion well, but in some cases (olfactory 
 part of anterior commissure) longitudinal dextro-sinistral 
 sections are necessary. 
 
 The condition of the atrophied centres may be roughly 
 stated as follows: As an example, after extraction of the 
 facial nerve, a series of trans-sections of the medulla show 
 simply an absence, a total absence, of the injured nerve- 
 
 ^ Ibidejji, Bd. xxv, Heft i, pp. 1-56.
 
 6 GUDDEN'S ATROPHY METHOD. 
 
 trunk in its course through the medulla, and of its nucleus 
 of origin. There is, architecturally speaking, a virtual void 
 in this region, which is filled up or compensated to a degree 
 by the ingrowth and overcrowding of adjacent normal 
 parts. There are no exudations, thickening of neuroglia, 
 areas of disintegration, etc., so that the topographical study 
 of the sections and the tracing out of the atrophy are not 
 hindered as in ordinary pathological specimens. 
 
 RESULTS OBTAINED BY GTIDDEN'S METHOD. 
 
 I propose mentioning these very briefly and without 
 criticism. Many of the questions to which the experiments 
 relate are novel and intricate ; further researches by other 
 methods may modify the views held by Gudden and his 
 pupils, but these views should be plainly stated so as 
 to serve as data for other observers. Enough will be found 
 in this abstract to justify, I think, the statement that we 
 already owe much in anatomy and physiology to this 
 method, and that it offers great possibilities for the 
 future. 
 
 The topics will be considered partially in chronological 
 order. 
 
 /, — Composition and connections of the commissura anterior 
 
 cerebri. 
 
 Von Gudden and Ganser have been able to resolve these 
 two questions in greater part by the atrophy method. It 
 has long been known that the c. A. consists of two unequal 
 fasciculi, variable in different animals, and these Ganser 
 calls (i) pars temporalis; (2) pars olfactoria. In general 
 terms, as revealed in normal sections, the p. t. is very much 
 larger in man and in monkeys, while in lower mammals, 
 particularly the hedgehog, mole, and rabbit, the p. o. is 
 highly developed and larger than the p. t.
 
 E. C. SEGUIN. 7 
 
 1. Pars temporalis. Von Gudden, in 1870/ published 
 experiments illustrating the nature of the pars temporalis. 
 
 ExPT. — In a newly-born rabbit the whole upper part of one 
 cerebral hemisphere was excised, above the basal ganglia. 
 Autopsy at eight weeks showed the commissura anterior normal. 
 
 ExPT. — In another rabbit the whole of one hemisphere was 
 removed. Seven weeks later the animal was killed, and sections 
 of the (hardened) brain showed complete atrophy of the commis- 
 sura anterior. The external capsule was, however, preserved in 
 the remaining hemisphere. 
 
 In both experiments there was atrophy of the corpus callosum, 
 complete in the latter. 
 
 Conclusions : the temporal division of the C. A. is a true 
 commissure, as is also the corpus callosum. 
 
 The external capsule has no direct connection w^ith the 
 C. A. 
 
 These experimental results have been confirmed by 
 Ganser. The conclusions are, moreover, supported and ex- 
 tended by the result of the careful study of complete series 
 of brain sections of man, monkey, and lower mammals, 
 made by Ganser.'' The sections were transverse and 
 horizontal, and in them the course of the C. A. (its pars 
 temporalis) was always distinctly into the temporal lobe, be- 
 yond the nucleus amygdalus. No fasciculi going to other 
 parts of brain (occipital lobes, Meynert et al.) could be 
 discovered. 
 
 2. Pars olfactoria. Von Gudden experimented on this 
 also, but his conclusions were invalidated by a source 
 of error discovered later on. It is to Ganser (op. cit.) 
 that we owe the absolute demonstration of its true nature 
 and distribution by means of von Gudden's method. 
 
 * Experimentaluntersuchungen uber das peripherische und centrale Nerven- 
 system. Westphal' s Archiv, Bd. ii, p. 693, experiments v and vi. 
 
 " S. Ganser : Ueber die vordere Commissur der Saugethiere. Westphal' s 
 Archiv, Bd. ix. Heft 2, 1878.
 
 8 GUD DEN'S ATROPHY METHOD. 
 
 ExpT. — The brain of two rabbits formerly operated by von 
 Gudden were cut into complete series of horizontal and transverse 
 sections. The injury consisted in destruction of the left tractus 
 olfactorious and frontal part of lobus pyriformis with a por- 
 tion of adjacent (dorsal) frontal lobe. The left bulbus olfac- 
 torius (lobus olf.) was very much atrophied. In both sets of sec- 
 tions (the horizontal best adapted) there was complete absence of 
 the olfactory division of the c. a. 
 
 ExPT. — Two other rabbits from whom von Gudden had re- 
 moved one of the bulbi olfactorii. These brains were shrunken 
 and overhardened, yet fairly good sections were obtained, enough 
 to show that in these two cases also there was complete atrophy of 
 the p. ol. of the c. a. 
 
 Conclusions : the pars olfactoria of the C. A. is also a 
 true commissure, and unites the two bulbi olfactorii. 
 
 Thus, by a few simple experiments and careful observa- 
 tions (objectively carried out) of preparations, is that 
 fanciful fabric, Meynert's olfactory chiasma overturned. 
 
 //. — Commissiira inferior cerebri. 
 
 Almost from his earliest experiments on the optic appara- 
 tus, von Gudden had observed that after removal of both 
 eyeballs, a portion of the chiasma and of the optic tracts 
 did not undergo atrophy. In his first published accounts ' 
 of the structure of the optic nerves, etc., he formulated this 
 observation by naming the surviving or non-atrophied 
 nervous band, commissura inferior cerebri, and expressed 
 the opinion that it was a commissure between the thalami. 
 In the first of his series of contributions "^ in Grczfe's Archiv, 
 these preliminary demonstrations are repeated. In the 
 third contribution, Mn reply to certain statements of Michel, 
 
 ' Experimentaluntersuchungen iiber das peripherische und centrale Nerven- 
 system. WestphaVs Archiv, Ed. ii, p. 693 (1S70). 
 
 Sitzung der viii Versammlung der Schweitzarischen Irrenserzte (Sept., 1872), 
 abstract in Psychiatrische Zeitschrift, Bd, xxx, p. 135. 
 
 ^ Ueber die Kreuzung der Fasern im Chiasma Nervorum Opticorum. Archiv 
 f. Ophthalmologie, Bd. xx, Heft 2. pp. 249-268, 1S74; 
 
 The second contribution is in Bd. xxi, Heft 3, pp. 199-205, 1875. 
 
 ^ Idem, Bd. xxv, Heft i, pp. 1-56, 1879.
 
 E. C. SEGUIN. 9- 
 
 he insists upon the distinction between this fascicuhis 
 and the one known as Meynert's commissure, which is 
 distinctly dorsal of the chiasma, and separated from it. The 
 commissura inferior, on the contrary, is mingled with the 
 tractus opticus and can only be discerned by excluding the 
 fibres of the latter, which is easily done by removal of both 
 eyeballs in the young animals, thus producing atrophy of 
 all the truly optic fasciculi. 
 
 Sometimes in the rabbit, dog, and cat, a slight depression 
 in the caudal-ventral aspect of the chiasm suggests its 
 limits. 
 
 In trans-sections of rabbits' tractus opticus no special limit 
 is discernible; but it is noticed that while the optic fibres 
 are coarse, those of the C. I. are fine. If one of these 
 trans-sections be treated with alcohol and then with carmine 
 the portion belonging to the C. I. is strongly tinged, while 
 the optic fibres remain white. The same reaction has been 
 obtained by Mayser in the T. O. of cyprinoid fishes. In 
 dogs, cats, monkeys, and man no such chemical distinction 
 exists. If the sections of rabbits' T. O. are placed unstained 
 (only colored by potassium bichromate) in glycerine, the 
 fibres of the C. I. appear as forming a clearer mass in the 
 dark field of the optic fibres. 
 
 In his fourth optic contribution,' von Gudden describes 
 the appearance of the optic apparatus in a human case of 
 long-standing one-sided blindness. Those parts in the 
 chiasma and tractus optici which correspond to the C. I. he 
 found unchanged, but not distinctly limited, and made up 
 of fibres having the same diameter as the optic fibres. The 
 C. I. in these trans-sections was dorsal of the optic fibres. 
 In the chiasma of animals it occupies the caudal, or the 
 caudal-ventral, aspect. 
 
 In his " Experimentaluntersuchungen," he states, that 
 
 ^ Archiv f. Ophthal., Bd. xxv, Heft 4, pp. 237-246, 1879.
 
 lO 
 
 GUDDEN'S ATROPHY METHOD. 
 
 the study of numerous trans-sections of the brain has shown 
 that the commissura inferior extends into the thalami optici, 
 connects them, and is probably in no wise associated with 
 the optic apparatus. After destruction of the lobus opticus 
 and the corpus geniculatum laterale, the commissura infe- 
 rior remains unchanged. 
 
 In connection with these important studies upon the 
 commissural systems of the brain (corpus callosum, com- 
 missura anterior, and commissura inferior) von Gudden has 
 formulated the following law of atrophy (of nutrition) : 
 
 That a true commissure, separated from one of its attach- 
 ments, must undergo bilateral atrophy. 
 
 UA^. 
 
 III. — Distribution of fibres in the optic apparatus. 
 
 As stated in the four articles in Grcefe's Archiv, von Gud- 
 den has reached the following conclusions : 
 
 1. That in birds there is complete decussation of fibres in 
 the optic chiasma. 
 
 ExpT. — Removal of one eyeball in a pigeon immediately after 
 birth. Autopsy in eight weeks showed atrophy of optic nerve 
 of same side, extending across the woven chiasm to the opposite 
 optic lobe, which is much reduced in size. 
 
 2. In the higher mammalia the decussation is variable, 
 but is always a semi-decussation. 
 
 ExPT. — In a rabbit,* the right eyeball was enucleated. Results : 
 {a) atrophy of right optic nerve ; {b) chiasma unchanged ; {c) 
 opposite (left) tractus opticus jwuHlb, as are also {d) the lobus 
 opticus, and {e) the corpus geniculatum laterale ; {/) complete 
 atrophy of opposite left tractus peduncularis. Negative results : 
 post-optic lobes (corpus quadrigeminum inf.) and commissura 
 inferior normal. 
 
 This experiment seemed to show that there was complete 
 
 ' It was always in newly-born animals that the various operations were done.
 
 E. C. SEGUIN. II 
 
 decussation in the rabbit, and so Gudden held for some 
 years, but different experiments, published in 1879,' demon- 
 strated beyond question the existence of a direct fasciculus 
 in the optic nerve of this animal. 
 
 ExPT. — By means of a sharp spoon, the optic lobe, corpus 
 geniculatum externum, subjacent part of caudex, and correspond- 
 ing optic tract are removed. Autopsy at age of six months. 
 Results : [a) total atrophy of injured tractus opticus ; {!)) oppo- 
 site optic nerve atrophies in greater part, but still showing a small 
 normal white fasciculus. 
 
 ExPT. — The brain was lifted up, and one half of chiasm 
 cut out with a sharp spoon. Results : complete atrophy of the 
 optic fibres, except a small (lateral) bundle in opposite optic 
 nerve — its direct fasciculus — (in this experiment the comraissura 
 inferior undergoes atrophy, as does also Meynert's commissure 
 dorsal of tractus). 
 
 As complementary to these results may be added the fact that 
 one of Gudden's assistants. Dr. Bumm,* carefully examined the 
 retina of the eye receiving only the direct fasciculus, and found 
 the nerve-fibre layer atrophied, except in the lateral (temporal) 
 segment of the organ. The retina was hardened in osmic acid, 
 and the whole of it cut and prepared. 
 
 Consequently, it must be held as demonstrated that in 
 rabbits there is semi-decussation, but to a slight degree only, 
 as the crossed fasciculus is enormously larger than the 
 direct ; and that this small direct fasciculus supplies the 
 temporal part of the retina in 'ologifti r/V^ 
 
 ExPT. — Right eyeball enucleated. Results : {a) complete 
 atrophy of right optic nerve ; \b) both optic tracts reduced in 
 size, the left smaller ; {c) both optic lobes smaller ; {d) both / / 
 
 corpora geniculata laterala smaller ; {e) caudal ^^^^ of /^ 
 thalami smaller ; (/) tractus peduncularis smaller. The commis-^ 
 sura inferior was preserved. 
 
 ExpT. — " Optic centres " (lobus opticus and corpus genicu- 
 
 ^ Arch. f. Ophthal., Bd. xxv, i, pp. 1-56, 1879. 
 
 " Bumm : Ueber die Vertheilung des Sehnerven in der Netzhaut des Kanin- 
 chens. WestphaVs Arckiv, Bd. xi, p. 264, 1881.
 
 12 
 
 GUDDEN'S ATROPHY METHOD. 
 
 / 
 
 latum laterale) removed on right side. Results : («) tractus op- 
 ticus of same side atrophied ; (^) both optic nerves reduced in 
 size, opposite (left) smaller ; {/) commissura inferior preserved. 
 
 In dogs, consequently, there is also semi-decussation, to a 
 greater extent than in rabbits, but still the direct fasciculus 
 is smaller than the crossed. 
 
 The course of the direct fasciculus in the dog (as seen 
 in horizontal sections of chiasm from above experiment), 
 lies in the dorsal border of right tractus opticus;' reaching 
 the chiasm it passes over the crossed fasciculus from the 
 other tractus, and then farom the medial border of the optic 
 nerve on same side (right). In rabbits this fasciculus lies in 
 the lateral border of optic nerve. 
 
 Numerous experiments of these kinds are recorded in the 
 various papers, and elaborate measurements given of the 
 areas of the affected optic nerves and tracts. 
 
 Gudden formulates the law of atrophy in the. optic ap- 
 paratus as follows : 
 
 1. The optic nerves and tracts degenerate (undergo 
 atrophy) when the retina is destroyed (removed). 
 
 2. The " optic centres" (lobus opticus and corpus geni- 
 culatum laterale) also undergo atrophy in such a case. 
 
 3. When the centres are removed, the degeneration does 
 not involve the retina. 
 
 In man, reasoning by analogy from the higher mammals 
 experimented on it, would seem that semi-decussation were 
 a logical necessity, yet several advocates of complete decus- 
 sation have appeared.' The|# arguments have, however, 
 been very weak, and Gudden made short work of their few 
 experimental claims.^ Cases of long-standing monocular 
 blindness in man, fitted for the direct solution of the prob- 
 lem, are not infrequent, but few of them have been properly 
 
 ' Chiefly Michel, Arch. f. Ophikal., Bd. xxiii, Heft 2, pp. 213-226, 1877. 
 "^ Arch. f. Ophthal., Bd. xxv, Heft I, pp. I-56, 1879.
 
 E. C. SEGUIN. 13 
 
 studied. Von Gudden has had the opportunity of examin- 
 ing four such cases. 
 
 Case i. — Man eighty-five years old ; blind in one eye from 
 early youth : phthisis bulbi. The atrophy is not total, many 
 normal nerve-fibres being found in affected optic nerve. Both 
 tractus smaller than normal. 
 
 Case 2. — Man thirty years old ; complete atrophy of left optic 
 nerve (not one fibre found in a careful microscopic examination) ; 
 both tractus reduced in size, one on opposite side smaller. 
 
 Case 3. — Male, dying at sixty, with left hemiplegia. Thirteen 
 years previously had had an attack of " apoplexy." Besides the 
 lesion in one internal capsule explaining the hemiparesis, there 
 was found an old hemorrhage which had destroyed the left corpus 
 geniculatum laterale, part of the thalamus opticus, and part of the 
 tractus opticus. The whole tractus was atroyjhied ; the oppo- 
 site optic nerve smaller, and the nerve on same side contained 
 many atrophied fibres, and was smaller (on section) in its medial 
 and central fasciculi. (The case is obscurely reported, and there 
 seems to be an error in the designation of the optic nerves.) 
 
 Case 4.' — Woman, aged seventy-three years. Glaucoma and 
 complete loss of sight in right eye for four years. The right 
 optic nerve was completely atrophied ; the right tractus opticus 
 seemed normal to naked eye ; the left tractus was smaller and 
 mostly gray ; on the chiasma itself, and upon the left tractus, 
 crossing chiasm from the frontal medial border of left optic nerve, 
 was a projecting white band, the direct fasciculus from left eye. 
 The microscope showed the left tractus all gray except in its 
 dorsal aspect, where some normal nerve-fibres were seen ; the 
 right tractus, on the other hand, presented (in sections) only 
 a small area of atrophied fibres (the direct fasciculus from the 
 right eye, and the commissura inferior). The degeneration and 
 atrophy extend to the optic centres, /. e., the left corpus genicula- 
 tum laterale and lobus opticus. 
 
 These cases certainly favor the theory of semi-decussation. 
 
 The following is a general sun:imary of von Gudden's re- 
 sults with respect to the optic apparatus. 
 
 I. That Johannes Miiller's law (which was only a physio- 
 logical postulate), that in animals whose visual axes are 
 
 ^ Arch. f. Ophthal., Bd. xxv, Heft 4, pp. 237-246, 1879.
 
 14 GUD DEN'S ATROPHY METHOD. 
 
 only lateral (monocular vision) there is total decussation, 
 and that in animals whose visual axes are more or less di- 
 rected forward (more or less perfect binocular vision) there 
 is semi-decussation, is a good law, supported by his (Gud- 
 den's) experiments and other facts. 
 
 2. That there is no anterior commissural (inter-retinal) 
 fasciculus in the optic apparatus, 
 
 3. That the posterior commissural fasciculus of classic 
 authors is his commissura inferior, which has no relation to 
 the optic system. 
 
 4. That the optic system in mammals consists only of 
 two bundles or fasciculi, one crossed and the other direct ; 
 the former the larger in rabbits, dogs, and cats (and quite 
 certainly in man). 
 
 5. That there is an accessory optic fasciculus, whose cen- 
 tral and peripheral terminations are yet unknown, viz., the 
 tractus peduncularis transversus. 
 
 6. That each optic tract is composed of three sorts of 
 fibres, of the same size in man, of different sizes and differ- 
 ent carmine reaction in animals ; optic fibres (crossed and 
 direct), fibres of the commissura inferior, and " hemispheric 
 fibres," whose course is not well known. These last- 
 named fibres are in the most lateral part of the tractus and 
 pass into the crus cerebri. 
 
 These results were confirmed by the experiments of 
 von Gudden's pupil — Ganser — on cats, published last year.' 
 This able observer has also carried the inquiry further, as 
 regards the cortical and retinal distribution of optic fibres, 
 affording a remarkable concurrence between von Gudden's 
 results and Munk's. 
 
 Ganser chose cats, for several reasons. They are vigorous 
 under operative interference ; they are more intelligent 
 
 ^ Ueber die periphere und centrale Anordnung der Sehnervenfasern und iiber 
 das Corpus bigeminum anterius, Westphal's Archiv, Bd. xiii, Heft 2, 1882.
 
 E. C. SEGUIN. 15'. 
 
 than rabbits, so that one can test their visual field ; they 
 have, to a remarkable degree, binocular vision, and thus re- 
 semble man ; their retina has a very high and clearly de- 
 fined structure, thus affording excellent opportunity for 
 ophthalmoscopic and microscopic study. 
 
 He relates three crucial experiments as follows : 
 
 ExPT. I. — For the determination of the direct fasciculus. On the 
 third day after birth, the left eyeball of a kitten was enucleated. 
 A fine forceps was introduced through the foramen opticorum, and 
 the tractus opticus of the same side torn or cut (at the same time 
 unintentionally a slight wound was made in the infundibulum and 
 left internal capsule). Cat recovered quickly and grew normally ; 
 was, however, lazy or stupid, more so than a brother kitten who- 
 had lost one hemisphere. Vision seemed good till tested, when 
 it was found it had hemianopsia, /. <?., was using only the temporal 
 half of its remaining retina. Autopsy at nine months. The only 
 part of optic apparatus left was a white nerve extend- 
 ing from right eyeball to the optic centres of same side ; no 
 chiasm. Right optic lobe and corpus geniculatum laterale 
 larger. The right tractus peduncularis transversus was smaller 
 than normal, the left almost invisible ; commissura inferior ab- 
 sent. Sections of the hardened retina showed normal nerve- 
 fibres (amyelinic in cat), only in its temporal two thirds ; on 
 nasal side fibres and ganglionic bodies atrophied. 
 
 Conclusion : there is a true fasciculus lateralis (or direct 
 fasciculus) in the optic system of the cat, and it supplies the- 
 temporal part of the retina. 
 
 ExPT. 2. — To determine the relation between the occipital cor- 
 tex and the optic apparatus. 
 
 In a kitten of same litter a portion of the left occipital lobe 
 was removed without wounding the cornu ammonis or the basal 
 ganglia. The injury was smaller but similar in location to that 
 done to a dog's brain by von Gudden.' This cat had no symp- 
 toms, but special tests (by means of a white ball swung around 
 the cat in direct and inverse directions) revealed right homony- 
 mous hemianopsia. Ophthalmoscopic examination showed 
 
 ^ Archiv f. Ophthal., Bd. xxi, Heft 3, pp. 199-205, 1875.
 
 l6 GUDDEN'S ATROPHY METHOD. 
 
 morbid changes in the temporal two fifths of the left retina, and in 
 the right eye more than the medial (nasal) half was atrophied. 
 Autopsy at nine months. Left hemisphere shows scar opening 
 freely into lateral ventricle (no inflammatory action). Left tractus 
 opticus smaller than right, revealing more of Meynert's commis- 
 sure on the crus. The optic nerves seemed little, if at all, changed 
 to the naked eye, but on measuring the area of sections under 
 the microscope, the right nerve-sections were found smaller. 
 
 Microscopic examination of the hardened retinae showed no 
 local elemental atrophy, but there was distinct thinning of the 
 retina in both left halves (left temporal and right nasal halves), 
 especially distinct in the papillae. 
 
 ExPT. 3. — For the same purpose. In a third kitten the left 
 hemisphere of the cerebrum was nearly all removed, the corpus 
 callosum and fornix being carefully cut in the medial line. The 
 animal grew well and was not at all paralyzed. The only move- 
 ment which he learned late was springing up on a chair, etc. 
 Was dull and had a bad memory. Tactile sensibility and reflex 
 movements seemed normal, but pricking was but little felt over 
 whole body. As in the former cat, there was right homonymous 
 hemianopsia. Ophthalmoscope showed tlie temporal part of 
 retina atrophied in left eye, while in the right the morbid changes 
 extended over two thirds of the retina (more than nasal half). 
 Autopsy at six months. Large serous sac in left brain ; olfactory 
 bulb and lobe, base of temporal lobe, and basal ganglia unin- 
 jured ; left thalamus smaller ; internal capsule atrophied ; left 
 half of pons, and left crus cerebri smaller ; left anterior pyramid 
 absent ; left optic centres (optic lobe and corpus genie, laterale) 
 are smaller. Both tractus optici smaller than those of normal 
 kittens of same age ; left more reduced. Under microscope the 
 section-areas of both optic nerves diminished, right more. Sec- 
 tions of hardened retinae showed, as in former case, a thinning of 
 retinal layers in both left halves — left temporal and right nasal 
 segments. 
 
 Conclusions : In cats the crossed fasciculus is larger 
 than the direct. In cats there is an anatomical connection 
 between the hemispheres (visual area in occipital lobe) and 
 the optic centres, extending thence to the retinae. 
 
 Gudden's old experiment,' shov^'ing that in rabbits re- 
 
 ' Experimentaluntersuchungen. etc. Westphars Archiv, Bd. ii, p. 693, 1870.
 
 E. C. SEGUIN. 17 
 
 moval of one hemisphere has no influence on optic nerves, 
 was repeated with the same results in six young rabbits. 
 
 It would thus appear that in lower mammals (those with 
 insignificant binocular vision) the optic-nerve fibres are chiefly 
 collected in the optic centres (optic lobe and corpus genicu- 
 latum laterale), while in higher mammals, dogs, cats, mon- 
 keys, as in man, there is a large, better differentiated cor- 
 tical connection. 
 
 The new and most interesting question of the anatomical 
 relation existing between the layers of the optic lobes and 
 the peripheral optic apparatus on the one hand, and the 
 visual area of the cortex cerebri on the other hand, was 
 studied in the rat as follows : 
 
 ExPT. A. — White rat three days old. Right eye enucle- 
 ated. Autopsy at nine months. Right optic nerve atrophied ; 
 left tractus much smaller than right ; left optic lobe and corpus 
 geniculatum laterale flatter and smaller. 
 
 ExpT. B. — White rat three days old ; removal of convex part of 
 right cerebral hemisphere (part of cornu ammonis also removed). 
 Autopsy in nine months. Both optic nerves alike ; right thalamus, 
 optic lobe, and corpus geniculatum a little smaller. Right inter- 
 nal capsule atrophied, crus cerebri smaller, anterior pyramid 
 absent. 
 
 The brains were subdivided into segments and hardened in a 
 two-per-cent solution of osmic acid (24 hours), and later in alco- 
 hol. The optic lobes were cut into fine trans-sections, which 
 were carefully examined.' 
 
 In rat A there was a reduction of the left superficial gray, and 
 nearly total atrophy of the superficial white {fibre visiva of Tartu- 
 feri^); intermediate white normal on both sides. [Effects — one- 
 sided in rat because of insignificance of direct fasciculus.] 
 
 In rat B, on the right side, the intermediate white was reduced, 
 and there was also partial atrophy of the right side of the tubular 
 gray (from what cause ?). 
 
 ' In the normal optic lobe Ganser distinguishes the following layers : i. zonal 
 fibres (present only in higher mammals) ; 2. superficial gray ; 3. superficial 
 white ; 4. intermediate gray ; 5. intermediate white ; 6. deep-seated white ; 
 and 7. the tubular gray. — Ganser: Vergleichend-anatomische Studien iiber 
 das Gehirn der Maulwurfs. Morphol. Jahrbuch, Bd. vii, p. 711. 
 
 '^ Fibre di origine del (ratio ottico in the strata bianco-chiereo superficiale of
 
 1 8 GUDDEN'S ATROPHY METHOD. 
 
 Conclusions : In rats the peripheral optic apparatus is 
 more intimately connected with the superficial gray and 
 white layers of the optic lobes, while the visual area of the 
 cerebrum is mostly in relation with the intermediate white 
 layer. 
 
 It may not be wholly superfluous to add that an impor- 
 tant negative conclusion from the work of von Gudden and 
 his pupils is, that neither the post-optic lobes (corpora 
 quadrigemina inferior) nor the corpora geniculata medialis 
 are connected with the optic apparatus ; a view which is 
 borne out by morphological conditions, etc. 
 
 IV. — Tr actus peduncularis transversiis. 
 
 When von Gudden published his first account ' of this 
 interesting fasciculus he was unaware that it had long been 
 known ; but he himself rectified his error by giving a biblio- 
 graphical account of it along with his later experiments.'' 
 The bundle was unknown to most of the older anatomists, 
 but Gall and Spurzheim^ described and figured it in several 
 plates as early as 1810. Von Gudden knew it (in con- 
 nection with his first optic experiments) as early as 1849. 
 In Leuret and Gratiolet's atlas" it is drawn by the artist 
 but not referred to by the author (Gratiolet). An Italian 
 investigator appears to have described it in 1861, under the 
 name oi fascio transversa. ^ 
 
 Tartuferi. (Sull' anatomia minuta dell' eminenze bigemine anteriori delle 
 scimmie. Rivista Sperimentale di Freniatria, v, F. iii, 1879. 
 
 ' Ueber einen bisher nichbeschreibenen N erven faserung im Gehirn der Sau- 
 gethiere und das Menschen. Westphal's Archiv, Bd. ii, p. 364, — 1870. 
 
 ^ Ueber den tractus peduncularis transversus. WestphaFs Archiv, Bd, xi, 
 Heft 2, 1880. 
 
 ^ " Atlas d'anatomie at de physiologic du systeme nerveux en general et du 
 cerveau en particulier." Paris, 1810. 
 
 * " Anatomic comparee du systeme nerveux." Paris, 1857. 
 
 ^ A proposal has recently been made by a distinguished American zoologist, 
 Wilder, " Anatomical Technology," New York (1882), to change this name to 
 cimbia. This term has no anatomical sense whatever its architectural value 
 may be. Von Gudden's name, on the contrary, if long, is descriptive and
 
 E. C. SEGUIN. 
 
 As its name correctly implies the tractus ped. trans, 
 traverses the crus cerebri (peduncul»»#). It apparently 
 arises from just within the medial border of the crus, / 
 passes over it in a line about half-way between the caudal 
 edge of the tractus opticus (and Meynert's commissure) 
 and the frontal border of the pons, extending latera\ and 
 dorsa%to the frontal edge of the lobus opticus where it 
 disappears. The tractus ped. tr. is thus distinctly traceable 
 only in the lower mammalia ; in man it is but slightly visible 
 in a part of its course.' 
 
 Von Gudden has endeavored, but thus far in vain, to de- 
 termine the true origin and destination of this fasciculus. 
 As regards its function he long ago learned something from 
 his various extirpation experiments on the optic apparatus. 
 The facts have already been incidentally stated, but a more 
 direct quotation is permissible. 
 
 ExPT — Extirpation of both eyes in rabbit. Results : atrophy 
 of optic nerves, of optic part of chiasm and tractus optici, of 
 primary optic centres, and of both tractus pedunc. tr. 
 
 ExpT. — Extirpation of one eyeball in rabbit. Results : atrophy 
 of optic nerve, of opposite optic tract (very slight of tract of same 
 side), of primary optic centres of opposite side, and of tractus 
 pedunc. tr. of opposite side. 
 
 ExPT. — In the dog after enucleation of one eyeball there are : 
 atrophy of optic nerve, of both optic tracts, and both sets of 
 primary optic centres, and of both tractus pedunc. tr. In all the 
 parts caudad of chiasm the atrophy is more marked on the side 
 opposite the enucleation. 
 
 ExpT. — Excision of part of occipital lobe in a dog, and re- 
 moval of one optic lobe in a rabbit, were followed, among 
 other results, by reduction in size of the corresponding tractus 
 pedunc. ir. 
 
 Conclusions: The tractus peduncularis transversus has a 
 
 equivalent to a definition — consequently it is good and should be retained. 
 From the context in Wilder, op. cit., § 1203, p. 475, it seems that he does not 
 know Gudden's now old discovery of the optic nature of this fasciculus. 
 
 ' Cf. Schwalbe : " Lehrbuch der Neurologic," p. 459. Erlangen, 1S81.
 
 20 GUD DEN'S ATROPHY METHOD. 
 
 functional and anatomical connection with the optic appar- 
 atus — more with its peripheral part, to which it stands in 
 the same relation as the crossed fasciculus of the tractus 
 opticus. Its connection with the primary optic centres is 
 direct, but less intimate ; its connection with the visual 
 area of the cerebral cortex is still less marked, but also 
 direct.
 
 GUDDEN'S ATROPHY METHOD: AND A SUM- 
 MARY OF ITS RESULTS. 
 {Second PaperJ^) 
 
 By E. C. SEGUIN, M.D. 
 ( With two wood-cuts.) 
 
 DURING the month of October of this year I went 
 to Munich specially to see Professor von Gudden's 
 preparations illustrating the various propositions advanced 
 in this analysis, and he very kindly showed them to me 
 himself with the greatest patience and system. I must also 
 thank Dr. Ganser for his courteous assistance in the labora- 
 tory, more especially with respect to details as to various 
 points of technique. 
 
 Before proceeding to continue the enumeration of Gud- 
 den's and Ganser's discoveries, it is necessary to insert cor- 
 rections and additions relative to two topics treated of in 
 the first paper. 
 
 First,' as to the pars olfactoria of the commissura anterior. 
 Professor von Gudden has recently been led to return to his 
 former view (against Ganser), that this commissure does not 
 unite the bulbi olfactorii, but the lobi o. To understand the 
 experimental results, one must have a clear idea of Gud- 
 den's view of the anatomy of the rabbit's olfactory bulb. 
 He considers the true bulb structure to sit like a cap over 
 the projected extremity of the lobus olfactorius ; in other 
 
 * Fide Archives for October, p. 126. [This paper should have appeared as 
 editorial matter, but was placed among original papers because the editorial 
 space had been engaged. — Ed.] 
 
 ' Unpublished. 
 
 Reprinted from the Archives of Medicine, Vol. x. No. 3, December, 1883.
 
 2 E. C. SEGUIN. 
 
 words, a portion of cerebral cortex is inclosed within the bulb 
 proper. Consequently it is impossible to remove the bulbus 
 olf. without also injuring or removing a portion of cerebral 
 cortex and white substance. 
 
 Expt/ — The lobus olfactorius is simply separated by incision 
 from its connections with the brain. The skull is not opened, 
 and no nervous substance removed. Autopsy shows that the 
 separated bulbus, though smaller, has retained its vitality, and the 
 olfactory nerves are normal. Trans-sections and horizontal sec- 
 tions give the following results : 
 
 In the bulbus there is no positive atrophy of its essential ele- 
 ments. In the olfactory lobe of the cerebrum (inferior part of 
 frontal lobe) there is distinct though slight atrophy, in size and 
 number, of ganglion cells in the cortex. In the centre of the 
 bulbus (inclosed cerebral substance) the white substance is much 
 atrophied. The tractus olfactorius shows much atrophy of its 
 white substance, more especially the lateral fibres. 
 
 Contrary to Ganser, the pars olfactoria of the C. a. is to a great 
 extent preserved. Some fibres are atrophied (absent), viz.: those 
 which in the normal state extended into the intra-bulbar projec- 
 tion of the olfactory lobe, which was cut off by the incision. 
 
 Consequently von Gudden holds that the pars olfactoria 
 of the commissura anterior connects two lobi olfactorii, a 
 view which is just as much opposed to Meynert's hypoth- 
 esis as the former was. 
 
 Second, an addition to the anatomy of the optic appara- 
 tus. Last year" von Gudden presented to the Science 
 Congress at Eisenach a r^sum^ of more recent experiments 
 upon the various constituents of the optic apparatus. He 
 repeated his demonstrations that the commissura inferior 
 cerebri and the hemispheric fasciculus of the tractus opticus 
 {vide Archives of Medicine, October, p. 139) are not di- 
 rectly connected, physiologically, with, the visual apparatus, 
 
 'To save repetition it is to be understood, unless specially otlierwise stated, 
 that the experiments cited in this paper are made upon newly-born rabbits, 
 which are allowed to live many months before autopsy. 
 
 ' Ueber die verschiedenen Nervenfasernsysteme in der Retina und im Nervus 
 opticus. — Tageblatt der 55 Versatmnlutig der Deulschen A'aturforscher und 
 Aerzte, Eisenach, 1882.
 
 GUD DEN'S ATROPHY METHOD. 3 
 
 He laid the results of new experiments before the Asso- 
 ciation with reference to : 
 
 1. The relations of the hemispheres to vision. If one 
 hemisphere, even inclusive of its corpus striatum, be removed 
 from a newly-born rabbit, it is impossible, after the animal 
 has become adult, to detect any impairment of sight ; and 
 both the pupils react normally. Gudden does not generalize 
 from this fact ; he simply advances it as true in rabbits. He 
 calls attention to a possible explanation of the conflict be- 
 tween this result and Munk's conclusions, by the fact that 
 Munk always operated on adult animals (or, at least, not 
 on the newly-born) whose cerebrum has acquired certain 
 functional attributes absent at an early period of life. 
 
 2. Centre of pupillary movements. He condemns as 
 erroneous his former statement, that after removal of one 
 lobus opticus the opposite^was abnormal. 
 
 {a) If one successfully removes the superficial layers of/ 
 one lobus opticus with a sharp spoon, it is observed that the 
 animal is absolutely blind in the eye opposite the lesion, 
 but the pupils are both normal in appearance and move- 
 ments. Post-mortem examination shows that the optic 
 nerve opposite the lesion is reduced in size, but is white 
 and contains normal fibres. The retina shows a general 
 diffuse reduction in the number of its nerve fibres. The 
 tractus ped. transversus on the operated side is normal. On 
 careful examination one sees a little latero-frontad of the 
 injured lobus opticus a small eminence, more prominent 
 than on the opposite normal side. The eminence is ren- 
 dered more distinct by partial atrophy of fibres of the 
 tractus opticus. 
 
 {U) If, in a newly-born rabbit, we remove one lobus opti- 
 cus, together with the above-described eminence, the adult 
 animal shows blindness of the opposite eye with wide dila- 
 tation of its pupil — a dilatation which is only slightly af-
 
 4 E. C. SEGUIN. 
 
 fected by the strongest daylight. The optic nerve and 
 retina are as described supra, but the tractus peduncularis 
 trans, on the operated side is completely atrophied. 
 
 Thus two "centres" are demonstrated : one in the lobus 
 opticus, for vision ; the other a little frontad of it, for reflex 
 pupillary movements. 
 
 3. The corpus geniculatum laterale is a third " centre," 
 probably a trophic centre for the optic tract and nerve, 
 since after its removal these parts undergo atrophy just as 
 after enucleation of one eyeball [except that the direct 
 (lateral) optic fasciculus remains normal in the former case]. 
 The various experiments bearing upon this question are 
 not yet complete. 
 
 4. If portions of one lobus opticus be removed, there 
 are found various segments of localized retinal atrophy (in 
 contradistinction to the diffuse atrophy noticed after re- 
 moval of the whole lobus opticus). Experiments upon this 
 further differentiation of nerve fibres are in progress. 
 
 5.' Within a year Gudden and Ganser have been success- 
 ful in dividing the optic chiasm longitudinally by passing 
 a long narrow-bladed knife through the unopened skull and 
 brain at the vertex. 
 
 Results : Complete atrophy of crossed fasciculi of optic 
 chiasm, with preservation of the lateral fasciculi^mmmissura /^ 
 inferior atrophied bilaterally. 
 
 f pass on now to studies in other regions of the nervous 
 centres, continuing the enumeration begun in the former 
 paper. 
 
 V. — Demonstration of the pyramidal tract? 
 In 1871, soon after the publication of Hitzig's first ex- 
 periments on the cerebral cortex, von Gudden removed the 
 
 ' Unpublished. 
 
 "^ Ueber Dementia Paralytica. — Correspondenzblatt f. Schweizer Aerzie, Bd. 
 ii, p. 79, 1872.
 
 GUDDEN'S ATROPHY METHOD. 5 
 
 frontal portion of one hemisphere (including the " motor 
 centres ") in newly-born rabbits. Preparations from the 
 adult brain showed atrophy of the corresponding crus 
 cerebi and anterior pyramid. The date of this experiment 
 is noteworthy ; it was certainly anterior to Flechsig's pub- 
 lications/ and is the first demonstration of the continuity 
 of the motor or pyramidal tract from the cerebral cortex 
 caudad. The experiment has since been repeated on the 
 dog with even more striking results. Specimens from the 
 dog I was able to examine. They showed, caudad of the 
 atrophied cerebral area, a complete absence of the medial 
 division of the crus cerebri, of the pyramidal fasciculi in the 
 pons, and of the pyramid strictly speaking. Below the 
 decussation the atrophy can be traced in the posterolateral 
 column of the opposite side. The anterior columns are 
 unchanged. The lemniscus {scJileife) is also much atrophied 
 on the operated side (compare statements in paragraph on 
 fasciculus ad tegmentum, infra). 
 
 VI. — Coimections of the cerebellum. ^ 
 
 ExPT. — In a newly-born rabbit one half of the cerebellum was 
 removed. At the autopsy of the adult animal it was found that a 
 very small part of the lateral portion of the hemisphere remained 
 attached to the medulla.' A full series of trans-sections was made 
 and studied. Results : 
 
 1. In the upper cervical region complete atrophy (absence) of 
 the fasciculus ad cerebellum * {Kleinhirnseitensirangbahn of 
 Flechsig) on the same side as the lesion. 
 
 2. In the caudal part of the medulla, we find likewise on the 
 same side as the injury : {a) atrophy of a group of cells lying 
 ventral in the medulla ("nucleus of anterior columns"), and of 
 
 'Yet Flechsig, in his most recent publication ("Plan des Menschlichen 
 Gehirns," p. vii, note ; Leipzig, 1883), still claims the demonstration as his. 
 
 * Ueber die Verbindungsbahnen des kleinen Gehirns. — Tageblatt der 55 Ver- 
 sarnmhing der Deuischen Naturforscher iind Aerzte, im Eisenach, 1882. 
 
 ^ It was also found that one post-optic lobe was much injured, and that the 
 corresponding crus cerebri had been touched by the spoon. 
 
 * I would propose this term, fasciculus ad cerebeUum, for the ascending 
 cerebellar fasciculus. It is in harmony with the names of adjacent centripetal 
 bundles, viz., the fasciculus cuneatus and the fasc. gracilis.
 
 6 E. C. SEGUIN. 
 
 (d) a second cell-group lateral in the medulla but ventrad of the 
 trigeminal root, the so-called " nucleus lateralis," from its sup- 
 posed connections with the lateral columns. In this region the 
 fibrse arciformes which go to form the beginning of the corpus 
 restiforme are absent. 
 
 d. Sections further frontad in the medulla show atrophy of 
 another nucleus on the same side as the injury, one situated dorsad 
 of ascending root of N. v. At level of N. vii there is complete 
 absence of the corpus restiforme. 
 
 4. In the various sections of the medulla it is seen that the 
 olive of the side opposite the lesion is almost wholly atrophied ; a 
 small part of it is still seen in the caudal sections, and probably 
 its survival is due to the bit of cerebellum which was left in the 
 operation. 
 
 5. Sections in the region of N. viii, and further frontad, show 
 a normal state of this nerve, of the upper olives, trapezium, and 
 of the (falsely) so-called " external auditory nucleus," or Deiters' 
 nucleus. The inner division of the processus ad medullam is about 
 normal ; while, as already stated, its outer portion, or corpus 
 restiforme, is totally (?) atrophied. 
 
 6. Sections through the upper part of the pons Varolii show 
 absence of processus ad pontem, without atrophy of trapezium or 
 of upper olives. It is exceedingly difficult to determine the con- 
 nections of the atrophied fibres, but many of them were certainly 
 in the opposite half of the pons, a few in the corresponding half, 
 and others were true commissural fibres. 
 
 7. Sections further frontad show absence of the processus ad 
 cerebrum on the operated side. The cells of the descending root 
 of N. V are absent. Further on the nucleus tegmenti of the oppo- 
 site side is almost entirely atrophied. The few cells remaining 
 are to be considered as evidence that another fasciculus probably 
 arises from the nucleus tegmenti and proceeds frontad. That 
 this survival of a few cells is not due to incomplete decussation of 
 the processus ad cerebrum is shown by the absolutely normal 
 state of the other nucleus : were there a semi-decussation, both 
 nuclei would exhibit atrophy. The preserved cell's of the nucleus 
 tegmenti are large, and are situated laterad of roots of N, iii. 
 Further frontad the number of cells in both nuclei tegmenti 
 become equal. 
 
 Consequently it may be stated that : — 
 
 I, The processus ad medullam (or corpus restiforme) has
 
 GUD DEN'S ATROPHY METHOD. 7 
 
 four origins, viz.: in three cell-groups or nuclei on the same 
 side in the medulla oblongata, a dorsal, a lateral, and a 
 ventral nucleus ' ; it is also derived from the olive of the 
 opposite side. 
 
 2. The processus ad pontem arises chiefly from cells in the 
 opposite half of the pons. It does not give fibres to the 
 pyramidal tract. Prof. Gudden does not consider his re- 
 searches on this point concluded. 
 
 3. The processus ad cerebrum proceeds frontad, as is 
 well known, and wholly decussates with its fellow, and has 
 its cell-connections in the caudo-medial part of the opposite 
 nucleus tegmenti. 
 
 VII. — Connections of the processus ad cerebrum. 
 In 1881, my friend, Prof. A. Forel, of Zurich, presented 
 to the German Science Congress at Salzburg the results of 
 a most interesting experiment upon this organ." 
 
 ExpT. — In a newly-born rabbit the right processus ad cere- 
 brum, the right side of velum medullare anterius, post-optic lobe, 
 and (involuntarily) a small bit of the right processus ad pontem 
 were removed. 
 
 Results : Atrophy of remaining (caudad and frontad of wound) 
 fibres of processus ad cerebrum. The atrophy is easily traced 
 frontad across the median line to the left nucleus tegmenti, which 
 is largely atrophied, more especially in its caudal part. Sections 
 frontad of nuclei tegmenti show no lesions. The ventral decussa- 
 tion of the tegmentum {ventrale Haubenkreiizung) is slightly un- 
 equal on the two sides. 
 
 But it is in the sections caudad of the injury that the most 
 interesting fact is found. 
 
 The right half of the vermis superior is extremely atrophic ; 
 some fasciculi going to the nucleus dentatus are visibly atrophied. 
 The nuclei (dentatus, dectiformis, embolus), as well as the corpus 
 restiforme, are perfectly normal. 
 
 ' This last was known to Deiters as an origin for fibres for the corpus resti- 
 forme, and Prof. Gudden has called it Deiters' nucleus ; but as this term has 
 been more generally applied to the remarkable group of large cells which are in 
 seeming relation to the acoustic nerve, he will abandon the name. 
 
 "^ Sitzungsberichte der 54 Versammlung Deutschen Naturforscher und 
 Aerzte, im Salzburg, 1881. In Wiejier med. Zeittmg, No. 46, 1881.
 
 8 E. C. SEGUIN. 
 
 Other lesions noted are : In consequence of the removal of the 
 post-optic lobe, there is a reduction in the volume of the right 
 lateral lemniscus {Sch/eifensc/iicht) as far caudad as N. vii. 
 Further caudad no lesions. There is slight atrophy of the so- 
 called crus of the post-optic lobe as far frontad as the corpus 
 geniculatum mediale, which seems normal. The only change in 
 the lobi optici is a very slight reduction of the deep white layer 
 on the right side. The r. descending root of N. v is almost 
 entirely absent, a few cells remaining at the level of the exit of the 
 nerve. N. viii is normal, as is also the fountain-like decussation 
 {Fontaineartige Kreutzung of Forel) in the tegmentum, which 
 Meynert and Wernicke would associate with N. v. 
 
 The important conclusion drawn from this experiment is 
 that the processus ad cerebrum arises in the vermis superior 
 of one side, and terminates (wholly?) in the nucleus teg- 
 menti of the opposite side. 
 
 VIII. — Central connections of the sciatic nerve. 
 
 This subject has been studied by means of Gudden's 
 method by his pupil and assistant, Mayser.' He gives a de- 
 tailed account of the histology and architecture of the 
 rabbit's spinal cords. Then he takes up the study of some 
 cords from which the sciatic nerve had been separated im- 
 mediately after birth, two by extraction of roots, and one 
 by section of the nerve. 
 
 The lesions found in the spinal cord are similar in nature 
 and general distribution, but more extensive and distinct in 
 the cases of extraction. 
 
 Results : WJiite substance. The only marked change is in 
 the posterior columns of the lumbar enlargement, which 
 are reduced in size on the same side as the injury. The 
 fasciculus cuneatus is alone atrophied, and this lesion 
 gradually diminishes in the dorsal region. In my examina- 
 tion of the specimens I observed in the lumbar region com- 
 
 ' P. Mayser : Experimentaller Beitrag zur Kenntniss des Ba^^s des Kanin- 
 chen-Ruckenmarks. Inaugural Dissertation. — iVestphaVs Archiv fiir Psy- 
 ckiairie, Bd. vii, Heft iii, 1877.
 
 GUDDEN'S ATROPHY METHOD. 9 
 
 plete absence of the posterior root zone on the injured side. 
 The posterior part of the lateral column is also very slightly 
 reduced in size. 
 
 T\\^ gray substance shows the greatest atrophy. At level 
 of greatest lesion, the anterior gray horn is much reduced 
 in size, and has lost its quadrangular shape, and is barren of 
 ganglion cells. Higher up the posterolateral group of 
 cells is preserved, especially in the cord of the animal whose 
 sciatic had been simply divided. Some ganglion cells on 
 the side opposite the injury, those sending cylinder-axis 
 processes toward the commissura anterior, must have per- 
 ished, for they are fewer in number than the same cells on 
 the injured side (evidence of crossed origin of some fibres of 
 sciatic). The posterior horn on the injured side is about 
 one third smaller than normal ; still it contains many small 
 ganglion cells, and the difference is mainly in the fibre-sys- 
 tem. The substantia gelatinosa is much atrophied, but 
 shows only a small reduction in the number of its cells. 
 The two commissures are reduced in size, the posterior 
 more so. 
 
 Essentially similar lesions were found in the cervical 
 spinal cord of a rabbit whose brachial plexus had been ex- 
 tracted. 
 
 IX. — Nuclei of the cranial nerves.^ 
 From personal examination of specimens. 
 
 NN. iii and iv. Expt. — Extirpation of the eyeball in a newly- 
 born rabbit, with careful extraction of orbital nerves. 
 
 Result : Atrophy in various parts of optic apparatus, as de- 
 scribed supra ; complete atrophy of NN. iii, iv, and vi. Series ot 
 trans-sections enable us to study the deeper atrophy of the nuclei 
 of these nerves. 
 
 ' Prof. V. Gudden has made no systematic publication of these valuable 
 results. Here and there in his papers he refers to the facts which have long 
 been known to him ; many prior to 1872, as shown by their citation in Kon- 
 dracki's Zurich thesis.
 
 lO E. C. SEGUIN. 
 
 I. N. iii.' Nucleus in well-known location, caudad of 
 lobus opticus and dorsad of fasciculus longitudinalis poste- 
 rior. By Gudden's method the nucleus is made out to be 
 triple. 
 
 [a) A fronto-ventral nucleus lying upon the fasc. long, 
 post., and giving origin to fibres which pass ventrally in a 
 straight direction. 
 
 ib) A caudo-ventral nucleus, partly dorsad of («), overlap- 
 ping it somewhat, but also extending (in its caudal part) 
 down to the fasc. long. post. This cell-group also gives rise 
 to direct vertical fibres. 
 
 if) A caudal nucleus lying dorsad of (<^), not reaching the 
 level of the fasc. long, post., and separated from the nucleus 
 of N. iv by a distinct barren interval. This contains and 
 gives origin to decussated and horizontally coursing fibres. 
 
 In a normal preparation, a horizontal section made just 
 dorsad of the fasc. long. post, shows cells of nuclei (i^) and (<5) 
 and cross-cut nerve fibres. One made further dorsad, pass- 
 ing through nucleus {c\ shows cells and mostly horizontally 
 running nerve fibres. 
 
 Similar sections from an animal experimented upon as 
 described above show^ : the ventral section^ absence of 
 fibres and cells on the same side as the injury ; the dorsal 
 section, on the contrary, exhibits atrophy (absence) of cells 
 and horizontal fibres on side opposite the injury. 
 
 The decussation of the fibres of N. iii occurs mostly by 
 the lateral fibres of the root, which pierce the ventral nuclei, 
 then turn pretty sharply mediad and decussate with their 
 homologues to connect with cells in the dorsal nucleus of 
 the opposite side. A few fibres decussate to reach this 
 nucleus through the raphe. The large majority of the root- 
 fibres of N. iii, constituting the medial roots, arise from {a) 
 and {p) and pass out directly. 
 
 ' Vide a short communication in Mittheilungen der Morphol. -Physiol. 
 Gesellschaft zu Munchen, in Miinchner Aerztlichen Intelligenzblatt, 1883.
 
 GUDDEN'S ATROPHY METHOD. II 
 
 Prof, von Gudden anticipates that by a better method of 
 extirpation of single ocular muscles with their attached 
 nerve filaments, we may yet be able to define a greater dif- 
 ferentiation of cell-groups in the oculomotor nuclei. In 
 this connection it is well to mention that in studying the 
 atrophied N. iii nuclei, the displacement produced by 
 atrophy of the two ventral nuclei on the side of the injury 
 must be borne in mind. In consequence of the virtual void 
 thus caused, the dorsal nucleus is displaced downward or 
 ventrally, and the fasc. long. post, in a dorso-mediad direc- 
 tion. Prof. Gudden has long ago appreciated and called 
 attention to this source of error in studying sections from 
 regions atrophied by his method. We will see other 
 illustrations of this further on {vide corpus mammilare and 
 von Monakow's researches on the thalamus). 
 
 2. N. iv. Its nucleus lies caudad of the caudal nucleus of 
 N. iii, and extends down to the fasc. long. post. In pathologi- 
 cal brains, sagittal, horizontal, and trans-sections show that 
 the atrophy involves only one nucleus, always the one on 
 the side opposite the injury. Consequently N. iv has a 
 simple origin, and its root-fibres wholly decussate. 
 
 3. N. V.' Two series of preparations were shown me : 
 I. Trans-sections from the nerve centres of a rabbit whose 
 trigeminus on one side had been cut between the pons 
 Varolii and the ganglion Gasserii ; the operation was done 
 by the old intracranial method, and was not entirely suc- 
 cessful. In the sections, a partial atrophy of the ascending 
 root can be traced frontad from a point between the second 
 and third cervical nerve to the level of exit of root. The 
 descending root and its peculiar cells also show marked 
 atrophy. The motor nucleus and root are, on the contrary, 
 well preserved. 2. Series of trans-sections from the nervous 
 centres of a calf presenting extensive malformations and 
 atrophies of the brain. 
 
 * Unpublished.
 
 12 E. C. SEGUIN. 
 
 The principal lesions presented by this brain, as exhibited 
 in a drawing of its basis, were: (i) absence of right olfac- 
 tory nerves and tractus (bulb partly preserved) ; (2) com- 
 plete absence of both optic nerves and tractus, with pres- 
 ervation of the commissura inferior; (3) partial atrophy of 
 right N. iii ; (4) preservation of both NN. iv ; (5) root of 
 right N. V seems totally atrophied, while its ganglion and 
 peripheral branches are preserved ; (6) absence of both NN. 
 vi ; (7) preservation of both NN. vii and of the other nerves 
 caudad 
 
 Sections from the level of second cervical nerve to that 
 of lobus opticus examined : On the right side there is com- 
 plete absence of the ascending (spinal) root of N, v 
 throughout its entire extent. The motor nucleus and root 
 are likewise completely absent. Of the descending root a 
 few cells exist, and a few fibres from them can be traced 
 caudo-ventrad toward the exit region of nerve-trunk. 
 
 From these specimens (and others) Gudden is willing to 
 recognize only three roots of the trigeminus, two sensory 
 and one motor. The other roots, as given by Meynert and 
 others, he regards as imaginary.' 
 
 4. N. vi. ExPT. — Described in paragraph on N. iii. Trans- 
 
 ' In this connection it may be interesting to refer to von Gudden's numer- 
 ous and ingenious experiments on the question of the trophic function of the 
 trigeminus. Some of these are already quite old and are cited by Kondracki 
 in his thesis in 1872 (E. Kondracki : Ueber die Durchschneidung des Nervus 
 trigeminus, Zurich), but although better than Snelling's they are unknown. 
 He admitted the fact that after section of the trigeminus ulceration of the 
 cornea and other changes of nutrition occurred in the eye. He took newly- 
 born rabbits and caused adhesion of the lids by operation (artificial ankylo- 
 blepharon). When this was entirely healed he cut the trigeminus by the intra- 
 cranial method. Opening the lids ten or fifteen days later he invariably ob- 
 tained normal coniese. Consequently he held the eye-lesions following section 
 of N. V to be traumatic in origin. More recently (oral communication) von 
 Gudden has operated by cutting the optic nerve behind the eyeball with the 
 least possible injury to other parts within the orbit. In this operation the 
 ciliary nerves are cut, and besides blindness there is anesthesia of the cornea. 
 But the lids retain their sensibility and by reflex action continue to protect the 
 eye from injury and dirt ; the cornea remains clear. Kondracki also refers to 
 operations on peripheral nerve-trunks after which, by care and cleanliness, the 
 skin of the foot remained free from the falsely so-called trophic changes. 
 Gudden was not aware that long before Brown-Sequard had demonstrated f&cts 
 like the last, showing ulcerations after nerve-sections to be traumatic.
 
 G UDDEN ' S A TROPH Y ME THOD. 1 3 
 
 sections show complete absence of trunk of nerve in the medulla, 
 and total atrophy of the cell-group laterad of genu of facial nerve. 
 In the calf's brain above described, while the facial nerves and 
 nuclei are well preserved, there is no trace of the fibres and 
 nucleus of NN. vi. In neither case do any cells remain. 
 
 Consequently the origin of the abducens nerve is simple 
 and direct. 
 
 5. N. vii. ExPT. — In the newly-born rabbit the facial nerve is 
 extracted from the Fallopian canal. If the operation is well done 
 a long piece of the nerve is brought away. 
 
 Results : Complete absence of extra- and intra-bulbar root of 
 nerve on operated side ; the ventral aspect of the medulla is a 
 little flattened. Sections show absence of root-fibres ; the site of 
 genu is vacant, and no cells can be found in the so-called 
 " lower nucleus," the three-grouped nucleus (rabbit) in the ventral 
 aspect of the medulla. On the other hand, the nucleus under the 
 genu of the nerve, near the floor of the fourth ventricle, is abso- 
 lutely normal ; comparison with a normal nucleus shows that no 
 cells are absent. 
 
 Consequently the facial nerve has only one nucleus — in 
 opposition to the teaching of nearly all anatomists who have 
 seen fibres of this nerve arise from the nucleus under its 
 genu. Even so recent an authority as Spitzka ' elaborate^ 
 ly describes this double origin of N. vii. 
 
 In estimating the full value of this experiment, the re- 
 sult of operation upon N. vi must also be borne in mind : 
 the two experiments mutually support one another, and 
 their agreement (in a large number of experiments by Gud- 
 den and several of his pupils) renders an error extremely 
 unlikely. 
 
 6. N. viii. As yet it has been impossible to complete 
 an experiment upon this nerve, because of the severe rota- 
 tory movements and death by exhaustion which follow 
 its section or extraction. Still, some important negative 
 conclusions have been reached indirectly. First, it has no 
 
 ' Contributions to Encephalic Anatomy, pp. 85-87, yournal of Nemous 
 and Mental Disease, April, 1880.
 
 1 4 E. C. SEGUIN. 
 
 connection with the so-called external auditory or Deiters' 
 nucleus, for a proof of which statement see Monakow's ex- 
 periment on corpus restiforme, p.-s^; second, in Gudden's 
 removal of one cerebellar hemisphere, the nerve and its nu- 
 cleus were perfectly normal. 
 
 7. N, X.* ExPT. — Extraction of central end of nerve and its 
 ganglia in rabbits. 
 
 Results : Atrophy of well-known sub-ependymal nucleus, dorso- 
 laterad of nucleus of hypoglossus. There is also complete atrophy 
 of a group of large cells lying ventrad of intra-bulbar root of the 
 nerve, and mediad of the so-called nucleus lateralis (which, as 
 shown supra, is one of the origins of the corpus restiforme.) The 
 tri-neural fasciculus (Spitzka's good name for the " gemeinschaftltche 
 aufsteigetide Wiirzel des seitlichen gemischten Systetns " of Meynert) 
 is also decidedly atrophied on the operated side. 
 
 8. N. xi. A number of apparently successful extraction ex- 
 periments have been made on this nerve, but the brains have not 
 yet been cut. 
 
 9. N. xii.^ ExPT. — Extraction (extra-spinal) of the hypo- 
 glossal in a rabbit from five to eight days old. 
 
 Results : Complete atrophy of the cells of the sub-ependymal 
 medial nucleus of hypoglossus, and absence of intra-bulbar 
 rootlets. In the series of sections which I examined, there re- 
 mained a few fibres and cells of the most caudal part of the 
 nucleus, from a slight incompleteness in the operation. The 
 ganglion cells dorsad of the atrophied nucleus, those of the oppo- 
 site hypoglossal nucleus, and the olives, were perfectly normal. 
 
 Hence the origin of this nerve is simple and direct. 
 
 These results are very instructive. They show, in an ap- 
 parently convincing manner, that nearly all the cranial 
 nerves have a much simpler origin than most anatomists 
 — especially those who allow physiological considerations 
 to warp their observation — describe. Yet the one nerve 
 which nearly all observers describe as having a simple 
 direct origin — N. iii — is conclusively proved by most 
 beautiful experiments to have a highly complex nucleus, 
 
 ' Unpublished. 
 
 ' Idem, but referred to briefly in several papers.
 
 GUD DEN'S ATROPHY METHOD. 15 
 
 and to arise by both direct and crossed fibres. Even if 
 we are not prepared to admit that these experiments of 
 von Gudden absolutely settle the question of the origin 
 of the cranial nerves, yet the results are sufificiently clear 
 and constant, it seems to me, to merit the attention of 
 anatomists, and to serve in some measure as a control 
 upon the mere study of sections from normal nerve 
 centres. 
 
 X. — Fasciculus longitiidinalis posterior. 
 
 There are no experiments directly bearing upon this part, 
 but from a consideration of some of the specimens above 
 referred to and some others, important negative conclusions 
 can be reached. 
 
 It is generally taught by anatomists that this fasciculus is 
 directly connected with the nuclei of the motor cranial 
 nerves, more especially those of NN. iii and iv, serving per- 
 haps as a means of associating or coordinating their action. 
 That this is not so, that it is an example of hypothetical 
 anatomy, is shown by the following facts. 
 
 1. In sections exhibiting atrophy of NN. iii and iv, the 
 fasc. long. post, are of equal and normal size, even when one 
 is displaced somewhat, as in atrophy of the oculomotorius. 
 
 2. In the mole, whose entire optic apparatus, including 
 NN. iii and iv, is undeveloped and as good as absent, there 
 is a well-developed fasc. long. post. 
 
 XL — Ganglion interpeduncular e. ' 
 This ganglion is a distinct external protuberance in rab- 
 bits, cats,'' and dogs ; in the monkey (Hapale), and in man 
 it lies concealed in the wall of the foramen coecum, but is 
 
 ' Gudden ; Mittheilungen uber das Ganglion Interpedunculare. — WesiphaVs ^ /"^ 
 Archiv, Bd. xi, Hft. 2, i88o. , _^ 
 
 "This part is not named, figured, or indexed by Wilder, op. cit. J The ./M. i-^-^ 
 ventral origin of the fasciculus Meynerti was jointly discovered by Gudden and /_ /^ 
 Forel prior to 1872, but not by Gudden's method. '^^, ^^^ (j
 
 1 6 E. C. SEGUIN. 
 
 not to be confounded with the substantia perforata posterior. 
 It consists mainly of small round or spindle-shaped ganglion 
 cells, the smallest of which are very similar to " nuclei " 
 of the neuroglia. It also contains some angular ganglion 
 cells. The little nests described by Forel (Haubenregion, 
 WestphaV s Archiv, Bd. vii, p. 393) are really made up of 
 most delicate amyelinic nerve fibres. 
 
 In horizontal sections of normal rabbit's brain, the G. I. 
 lies caudad of the foramen coecum, between the lemnisci 
 (Schleife). From its frontal extremity issue the two fascic- 
 uli Meynerti, and laterad of these are cross-sections of 
 bundles of N. iii, and longitudinal sections of the pedun- 
 culus corporis mammillaris {vide infra). A little frontad 
 and quite laterad of the foramen coecum are cross-sections 
 of the tractus peduncularis transversus. 
 
 ExPT. — Removal of one ganglion habenulse in a rabbit a few 
 days old. 
 
 Results : Complete atrophy of corresponding fasciculus Mey- 
 nerti, of its point of entrance into ganglion interpedunculare, and 
 of the ganglion itself on both sides of the median line. No 
 atrophy of cells observed. It is not stated whether fibres of 
 origin of fasc. M. decussate or not in the ganglion, but from the 
 illustration accompanying the article, it would seem that they 
 did. 
 
 XII. — The corpus inammillare? 
 
 Von Gudden describes the external appearance and 
 general configuration of the C. M. in rabbits, cats, dogs, 
 monkey (Hapale), and in man. Each animal presents 
 some difference in external configuration of c. M. The 
 rabbit presents lateral accessory eminences, which are the 
 lateral ganglia. 
 
 Microscopic examinations (trans-sections), however, show 
 that in all animals there are two sets of nuclei, a medial 
 and a lateral on either side. 
 
 ' Gudden : Beitrag zur Kentniss des Corpus Mammillaie und der sogen- 
 annten Schenkel des Fornix. — WestphaV s Archiv, Bd. xi, Hft. 2, 1880.
 
 G UDDEN ' S A TROPH Y ME THOD. 1 7 
 
 / I. The lateral ganglion of c. M. It contains large gang- 
 lion waiUc . From its lateral part arises a fasciculus, the 
 pedunculus corporis mammillaris. In the rabbit this fascic- 
 ulus lies mediad of crus cerebri ; most N. iii fibres pass out 
 through it. The ganglion interpedunculare and the begin- 
 ning of fasciculus Meynerti lie mediad of the ped. corp. mam. 
 It tends dorso-latero caudad to enter the pons Varolii. The 
 columnar fornicis lie mediad of it. It almost joins the lem- 
 niscus (Schleife), but can be distinguished from it by : 
 
 {a) Its larger-sized nerve fibres, which can be traced 
 ventro-laterad of the lemniscus, through the trapezium, 
 into the medulla oblongata, as far caudad as the olives. 
 
 {b) By any experiment which causes atrophy of the 
 pyramidal tract iindc p. 238), such as removal of the frontal 
 part of the brain, or of one hemisphere. On examining 
 trans-sections from such a case, one can trace, caudad of 
 the commissura anterior, atrophy of the fine fibre system 
 of the lemniscus, as well as of the pyramidal tract proper 
 on the side of the injury. The large fibres of the ped. 
 Corp. mam. ventro-laterad of the absent lemniscus, between 
 it and the site of the pyramidal tract, are, however, pre- 
 served. In passing through the trapezium (never ventrad 
 of it), it becomes more medial and approaches its fellow : 
 in the trapezium the fibres are somewhat scattered, but 
 caudad of it they once more unite to form a compact 
 bundle lying dorsad of the pyramid (which is mostly made 
 up of fine fibres). In the region of the olives the fascic- 
 ulus tends more dorsad and is lost. 
 
 Conclusion : the lateral ganglion of C. M. is unconnected 
 with the hemisphere. 
 
 2. Medial ganglion, made up of smaller cells. Two fasciculi 
 arise from it, viz., the fasciculus Vicq D' Azyr (Meynert's 
 radix ascendens of columna fornicis) and the fasciculus ad 
 tegmentum {Haubenbiindcl^.
 
 15 E. C. SEGUIN. 
 
 {a) Fasciculus ad tegmentum. Vide special paragraph, 
 
 {b) Fasciculus Vicq D' Azyr. 
 
 ExpT. — After removal of one hemisphere (rabbit) this fasci- 
 culus and the medial ganglion of c. M. undergo partial atrophy. 
 Refers to illustrations by Cruveilhier, Van der Kolk, and other, 
 of unsymmetrical (atrophied) human brains showing atrophy of 
 one of the two eminences of the c. m. 
 
 ExpT. — Removal of one hemisphere and of the frontal part of 
 the thalamus. 
 
 Results : Complete atrophy of fasc. Vicq D' Azyr and of the 
 ventral part of medial nucleus of C. m. 
 
 Conclusion : The fasc. Vicq D' Azyr arises from the 
 ventral part of the medial ganglion of C. M., and, extending 
 dorso-frontad (in rabbit), is distributed to the nucleus 
 anterior of the thalamus (tuberculum anterius). There it 
 also enters into indirect connection with fibres of the 
 corona radiata, which extend to the cortex cerebri (to 
 vicinity of motor area, according to Von Monakow's ex- 
 periments — vide i?ifrd). 
 
 XIII . — Connections of the coluinncs fornicis.^ 
 
 ExPT. — Removal of one hemisphere and section or removal of 
 both Ammon's horns. 
 
 Results : Trans-sections show complete atrophy (absence) of 
 both columnas fornicis ; the fasciculus Vicq D' Azyr is reduced 
 in size on the side of absent hemisphere. 
 
 ExpT. — Removal of one hemisphere without injury to cornu 
 Ammonis. 
 
 Results : Columns fornicis normal ; fasciculus Vicq D' Azyr 
 somewhat reduced in size on operated side. 
 
 ExPT. — Incision of one hemisphere and section or laceration 
 of fimbria on one side dorsad of commissura anterior. 
 
 Results : Disappearance of columnae fornicis on operated side ; 
 very slight reduction in size of fasc. Vicq D' Azyr. 
 
 Dr. Ganser's Expt. — After removal of one - eyeball, a fine 
 
 " Beitrag zur Kenntniss des Corpus Mammillare unci der sogenannten 
 Schenkel des Fornix. — Westphal's Arckiv, Bd. xi, Hft. 2, 1880.
 
 GUDDEN'S ATROPHY METHOD. . 1 9 
 
 forceps was introduced through the foramen opticum in the direc- 
 tion of the chiasm, with the intention of destroying the tractus 
 opticus on one side. Besides this, however, a slight cut was made 
 in the tuber cinereum which severed one columna fornicis. 
 
 Results : Complete atrophy of injured columna fornicis frontad 
 of corpus mammillare ; caudad the atrophy could be traced be- 
 hind the c. M. to the point where the col. fornicis decussates with 
 its homologue {inde next section) to the side opposite the injury, 
 in the central gray matter. The fasc. Vicq D' Azyr were normal. 
 
 These experiments show that the columnae fornicis enter 
 into the formation of (are continuous with) the fimbria, 
 fornix, and cornu Ammonis. 
 
 They also prove in the most positive manner that there 
 is no continuity between the columnse fornicis and the 
 fasciculi Vicq D' Azyr, and that these fasciculi do not form 
 a genu or loop in or around the corpus mammillare, as 
 claimed by Meynert.' 
 
 XIV. — Composition of the colunmcB fornicis. 
 
 This is much more complex than is taught in works on 
 nervous anatomy, and an approach to an exact solution has 
 only been reached by von Gudden within the last year, 
 after a study of many years, embracing the performance of 
 numerous experiments. 
 
 To Ganser, his very able and ingenious collaborator, we 
 owe the first and principal step in this series of discoveries, 
 viz.: the experimental determination of the passage of the 
 columna fornicis through the corpus mammillare (contrary 
 to all previous writers, who taught that it arose from the C. 
 M.), and of its origin further caudad and dorsad, in the cen- 
 tral gray surrounding the third ventricle. 
 
 In 1880 ' von Gudden published an article upon the cor- 
 pus mammillare and columnae fornicis, in which he claimed 
 the demonstration of two additional fasciculi of the columna 
 
 'Strieker: " Manual of Histology," Am. ed., pp. 691-2, fig. 269. New 
 York, 1872. 
 "^ Op. cit.
 
 E. C. SEGUIN. 
 
 fornicis, besides the well-known bundle studied by Ganser. 
 In the past year he has found still a fourth bundle in this 
 system, but has not made the discovery public. Conse- 
 quently, instead of giving an abstract of the paper of 1880, 
 I shall give a r^sumtf oi what Prof. Gudden demonstrated to 
 me, and of his explanations. 
 
 He now considers^the so-called columna fornicis {Fornix- 
 sdule) consist of four fasciculi, viz. : 
 
 1. A ventral crossed fasciculus. 
 
 2. A dorsal 
 
 3. A dorsal direct fasciculus. 
 
 4. A ventral " 
 
 I. The ventral crossed bundle is the one long known as 
 the columna fornicis in its passage through the tuber cine- 
 reum to the corpus mammillare (Meynert's radix descendens 
 fornicis). Its true origin and course were discovered by 
 Ganser in 1878 by an experiment described on p.^JJ* The 
 origin he found to be in the central gray near the third ven- 
 tricle, but not from any distinct cell-group. In most ani- 
 mals these fibres of origin are scattered, and their course is 
 difficult or even impossible to make out, but in rabbits 
 (with a few individual exceptions), in mice, and moles the 
 fibres are aggregated into considerable fasciculi, so that 
 carmine, gold, and osmic preparations exhibit distinct pict- 
 ures. As seen in the typical rabbit the fine bundles com- 
 ing from the central gray run ventro-frontad ; they are 
 mediad of the fasciculi Meynerti. At a point caudad and 
 dorsad of the medial ganglia of the corpus mammillare these 
 fine bundles completely decussate ; they now form a large 
 fasciculus on either side, which curves around the medial 
 ganglion of the c. M., passes frontad between it and the lat- 
 eral ganglion. It apparently issues from the frontal aspect 
 of the c. M. into the tuber cinereum, takes a direction dorso- 
 latero-frontad to a level dorsad of the commissura anterior,
 
 G UDDEN 'S Al ROPH Y ME THOD. 2 1 
 
 where it enters into the formation of the root of the fornix. 
 
 2. The dorsal crossed bundle joins No. i at a point fron- 
 tad of the tuber cinereum. It is demonstrated by the pre- 
 viously cited experiment of removal of one hemisphere and 
 of its cornu Ammonis without injury to the root of the fornix 
 (region where columnse fornicis enter fornix). In a series 
 of trans-sections from such a brain, one sees, as stated supra, 
 that fasciculus No. i is completely absent caudad of C. M. 
 in it, and in the tuber cinereum ; but in the sections frontad 
 of this point, at the level of the commissura anterior, a bun- 
 dle of transversly-cut nerve fibres is seen close to the site of 
 the atrophied columna fornicis — just mediad of it. These 
 fibres are pale ; they have taken up much less carmine than 
 those of the normal fasciculus No. i on the opposite side. 
 Still further frontad, over the commissura anterior, these 
 fibres diverge toward the median line, cross it, and enter 
 the fornix of the opposite non-operated side. Indeed, 
 without special preparation, after this experiment, by turn- 
 ing what remains of the fornix over frontad, it is easy to 
 see with the naked eye a fasciculus passing from the normal 
 half of the fornix ventrad toward the median line. In the 
 sections it is also evident that this fasciculus (No. 2) is ab- 
 sent in the column opposite the injury, while its main 
 bundle (No. i) is present. 
 
 3. The dorsal direct bundle is made evident by Cau- 
 ser's experiment of wound in the tuber cinereum p. o ^y ^ 
 The inferior fasciculus (No. i) is absent on one side in the 
 sections, but dorsad of the commissura anterior there ap- 
 pears near the site of the absent bundle a round section of 
 fibres. These can be traced caudad in the series of sections ; 
 it spreads latero-dorsad, describing a curve with convexity 
 outward, to reach the dorso-lateral part of the thalamus, 
 where it seems connected with a cell-group. It may, how- 
 ever, have an origin at a point further ventrad in the curve,
 
 22 E. C. SEGUIN. 
 
 where there is a nest of larger cells. In this course the 
 fibres of fasciculus No. 3 enter into the formation of the 
 stratum zonale. As seen dorsad of the commissura ante- 
 rior its fibres are smaller than those of fasciculi i and 2. 
 After removal of one Ammon's horn it undergoes atrophy 
 on the same side as the injury. If von Gudden were sure 
 that this fasciculus (No. 3) ended in the above-mentioned 
 cell-group in the thalamus, he would call it the thalamic root 
 of the fornix, but he now prefers to call it the dorsal direct 
 bundle. 
 
 4. The ventral direct bundle.' After Ganser's experi- 
 ment in sections through the tuber cinereum, two or three 
 little stained fasciculi (cross-cut) are seen to join the 
 columna fornicis, or on the operated side to tend toward its 
 site. Their ultimate course frontad is unknown, but it is 
 certain that they undergo atrophy on the same side as the 
 injury when the cornu Ammonis is removed on one side. 
 Caudad the small bundles can be traced in a direction 
 ventro-medio-dorsad into the central gray matter frontad of 
 corpus mammillare : a distinct nucleus has not been ob- 
 served. 
 
 Prof. V. Gudden believes that bundles i and 4 con- 
 tribute to form that part of the fornix which lies under the 
 corpus callosum and is known as the longitudinal fornix. 
 Bundles 2 and 3 diverge and take a dorso-laterad course in 
 the fornix. 
 
 The taenia thalami^ crosses bundle No. 3, passes caudad of 
 it without giving it any fibres. This is distinctly seen in 
 such atrophy preparations as involve atrophy of the entire 
 columna fornicis : the cross-section of the taenia has the 
 same diameter on either side. Neither have any of the prep- 
 arations afforded evidence of a connection between the 
 columna fornicis and the stria cornea. 
 * Unpublished.
 
 G UDDEN ' S A TROPH Y ME THOD. 2 3 
 
 XV. — Fasciculus ad tegmentum {Haubenbiindet)^ 
 
 This was partly described by Prof, von Gudden in his 
 paper on the corpus mammillare (1880). He then correctly 
 described its course, but its true origin, and more especially 
 its termination in a distinct ganglion in the tegmentum, 
 were not discovered until this year, and I have the privilege 
 of first making the facts public. 
 
 Origin of the fasciculus. In sections from a rab- 
 bit which had undergone removal of one hemisphere 
 together with the anterior part of the thalamus, the fascic- 
 ulus Vicq D' Azyr is completely absent on the operated 
 side, and the medial ganglion of the corpus mammillare to 
 a great extent atrophied. However, one sees in the trans- 
 sections, a fasciculus arising from the remains of the medial 
 ganglion of the corpus mammillare ; it extends a little way 
 dorsad, then turns abruptly ventro-caudad to enter the teg- 
 mentum. 
 
 In a very successful (z.^., in the right plane) horizontal sec- 
 tion from a normal rabbit brain the horizontal course of the 
 fasciculus can be traced a long way. In the frontal part of 
 such a preparation are the commissura anterior and cross- 
 sections of the columnae fornicis ; then, proceeding caudad, 
 in the median line the slit-like opening of the third ven- 
 tricle ; on either side of this a large bundle is seen in cross- 
 section, the fasciculus Vicq D' Azyr ; from this a bundle of 
 fibres diverges caudad, tending toward the median line ; it 
 passes mediad of another large bundle seen in cross-sec- 
 tion, viz.: the fasciculus Meynerti ; a little further caudad it 
 lies mediad of the emerging roots (cross-cut) of N. iii, 
 and finally is lost very near the median line, just ventrad of 
 the fasciculus longitudinalis posterior. 
 
 The exact caudad connection (termination) of the fasc. ad 
 tegmentum was ascertained by the following experiment. 
 ' Unpublished.
 
 24 E. C. SEGUIN. 
 
 By passing a very delicate knife vertically through the cor- 
 pus callosum to the base of the brain, the chiasm and one 
 medial ganglion of the corpus mammillare were divided. 
 [Ganser's experiment of injury to medial ganglion by 
 passing a forceps through the foramen opticum in a kitten 
 also afforded a similar demonstration.] The study of trans- 
 sections from these two cases showed the following results in 
 parts caudad of the injured ganglion. There was no trace 
 of the fasc. ad tegmentum on the side of the injury, and this 
 atrophy could easily be traced as far back as a point a little 
 caudad of N. iv, ventrad of the fasc. long. post. The\ on 
 the normal side is a beautiful well-defined cell-group, of 
 which there is no trace on the side of the absent fasciculus. 
 Both in the cat and rabbit the demonstration of this new 
 ganglion was most conclusive. 
 
 Now that the terminal cell-group is known it is easy, in 
 horizontal trans-sections from normal brains, to trace the 
 fasc. ad tegmentum all the way from its origin to its ter- 
 mination. 
 
 Observing more closely the mode of origin of the (con- 
 joined) fasc. ad tegmentum and the fasc. Vicq D' Azyr, by 
 means of numerous series of sections, von Gudden has 
 recently discovered that the medial ganglion of the 
 corpus mammillare is composed of two distinct cell-groups 
 or nuclei : a dorso-frontal nucleus which gives origin to the 
 fasc. ad tegmentum, and a ventro-caudal mass from which 
 springs the fasc. Vicq D' Azyr. This constitutes an addi- 
 tion to our knowledge of the corpus mammillare, as stated 
 on p.**fl[i)n 
 
 I propose the term fasciculus ad tegmentum for the 
 German noun Hanbenbiindel. This has Prof. Gudden's 
 approval. 
 
 XVI. — Corpus restiforme and Deiters' nucleus. 
 
 Dr. C. von Monakow, assistant physician of the asylum of
 
 GUDDEN'S A TROPH Y ME THOD. 2% 1 
 
 St. Pirminsberg, in Pfafers, near R(|gatz, has carried on a / (^/ 
 number of most interesting researches by Gudden's method. ^ 
 He has more especially occupied himself with the cortex 
 cerebri and basal ganglia, a field not specially entered upon 
 by Gudden. He also made one experiment upon more 
 peripheral parts/ which it is best to analyze immediately 
 after Gudden's studies. 
 
 Dr. Monakow gives an historical account of Deiters' 
 nucleus, or the so-called external acoustic nucleus. 
 
 ExPT. — In a newly-born rabbit, left hemi-section of the spinal 
 cord, just below the decussation. 
 
 Physiological results : Complete left hemiplegia with nearly 
 complete recovery later. At first little reaction to needle-pricks 
 on both sides of body, but later was more marked (though incom- 
 plete) on the left side. State of face not specially stated. 
 
 Autopsy in six months. 
 
 Gross changes : Hemi-section not quite complete ; a part, inner 
 half, of fasciculus gracilis (GoU's column) and a small part of the 
 anterior column remain. Evident ascending degeneration in 
 medulla. Left side of cord smaller caudad of section. Left 
 vermis superior cerebelli flatter. 
 
 Microscopic examination of sections as far frontad as thalamus. 
 
 {a) Changes frontad of injury : (i) Complete atrophy of fascicu- 
 lus cuneatus and its nucleus ; (2) partial atrophy of fasciculus 
 gracilis and its nucleus ; (3) complete atrophy of fasciculus ad 
 cerebellum ; (4) corpus restiforme reduced one half, atrophied, 
 chiefly in its medial part ; (5) the atrophy of the nucleus of the 
 fasc. cuneatus is by far more marked in its lateral mass, which can 
 be traced to the caudal level of N. viii roots (the medial nucleus is 
 reduced one third without evident histological changes) ; (6) the 
 inner division of the processus ad medullam (or ascending N. viii 
 of Roller) is but slightly altered — at level of true N. viii roots it is 
 smaller on the operated side, because of absence of fibres coming 
 to it horizontally from corpus restiforme ; (7) at this level the 
 large cells of Deiters' nucleus are nearly all lost on the same side 
 as the injury, more especially in its latero-dorsal aspect — this 
 atrophy blends with that of the adjacent corpus restiforme — the 
 
 ' Monakow, Experimenteller Beitrag zur Kenntniss des Corpus Restiforme, 
 des " ausseren Acusticuskerns," und deren Beziehungen zum Riickenmark. — 
 WestphaVs Archiv, Bd. xiv, Hft. i.
 
 26 E. C. SEGUIN. 
 
 acoustic root-fibres which apparently arise from this nucleus are 
 seen perfectly intact in the wasted nucleus — all these roots are 
 normal and equal on the two sides ; (8) in the cerebellum the 
 atrophy can be indistinctly traced into the vermis superior, 
 whose cortex and medulla are certainly less developed than 
 on the healthy side ; (9) the left nucleus lateralis is almost 
 wholly atrophied {vide ^ vi, on origin of processus ad medul- 
 1am) ; (10) the left formatio reticularis in its lateral part is 
 generally reduced and poorer in cells, a condition which can be 
 traced as far frontad as the lobus opticus ; (11) the pyramid op- 
 posite the injury is slightly smaller, but after a short distance 
 frontad this atrophy ceases ; (12) the prolongation of the lemnis- 
 cus {Schleifj^ in the medulla is slightly atrophied on the same side 
 as the injury. No changes in lobi optici or beyond ; these were 
 particularly searched for, as Monakow's principal idea in making 
 the experiment was to trace an ascending atrophy to the brain. 
 
 {b) Changes caudad of the injury : Complete atrophy of 
 pyramid below hemi-section, on same side of course. 
 
 The perfectly normal parts of medulla are the medial part of 
 formatio reticularis, the fasc. long. post, (continuation of anterior 
 column ?), the upper olives, and all the nerve nuclei and roots. 
 The lower olive on the operated side is a trifle smaller on the 
 operated side, and the same is true of the ascending root of N. v, 
 but the word atrophy can hardly be applied. 
 
 Conclusions: i. That the processus ad medullam {vide ^ 
 vi) is made up of several bundles: of the processus ad cere- 
 bellum {Kleinhirnseitensirangbahn), fibrae arcuatae, fibres 
 from both olives and the formatio reticularis, and largely in 
 its medial portion of fibres derived from the fasciculus 
 cuneatus through its lateral nucleus. 
 
 2. This last portion of the atrophied corpus restiforme 
 can be traced to a connection with the large cells of Deiters' 
 nucleus. 
 
 3. Deiters' nucleus is certainly not connected with the 
 acoustic nerve. 
 
 4. The atrophic fasciculus ad cerebellum is in relation 
 with the caudal part of the vermis superior (compare p. -'"'gQ / ^ 
 on connection of processus ad cerebrum, with frontal party / 
 of vermis, as shown by Forel).
 
 GUDDEN 'S A TROPH Y ME THOD. 27 
 
 The most important result of this experiment is that 
 concerning the relations of Deiters' nucleus. With singular 
 unanimity it is considered by anatomists as the outer 
 acoustic nucleus, because they have traced root-fibres of 
 N, viii into it. So recent an authority as Spitzka' not only 
 admits it as a nucleus of N. viii, but declines to consider 
 the usual division into an internal and external nucleus. If 
 any anatomist could see, as I have seen, the N. viii fibres 
 absolutely normal in the area of Deiters' nucleus while 
 almost all the cells were absent, he would begin to reflect 
 on the uncertainty of the simple study of normal sections, 
 however carefully or conscientiously carried out. The an- 
 nals of encephalic anatomy are replete with the errors due 
 to exclusive devotion to the Rolando-Stilling method, and 
 it is high time that its delusive teachings be corrected by 
 the other special methods of research. 
 
 XVII . — Relation of cortex cerebri to adjacent parts. 
 The most important researches of Dr. von Monakow, 
 those which are in all respects his own, and which, if con- 
 firmed, will add greatly to our comprehension of cerebral 
 architecture and physiology, are those upon the relations 
 between cortical areas and portions of the thalamus, the 
 corpora geniculata, and the lobus opticus. A portion of 
 his experiments have already appeared in print,'^ and two 
 other contributions were made this year to the German and 
 the Swiss Science Congresses respectively. He was led to un- 
 dertake these researches partly by Munk's physiological 
 experiments, and partly by the fact, noted several times by 
 Gudden, that after removal of one hemisphere in the rabbit, 
 
 '"Contributions to Encephalic Anatomy," chapter i, appendix note 42. — 
 youmal of Nervous and Mental Disease, April, 1 880. 
 
 ' Ueber einige durch Extirpation circumscriptar Hirnrindenregionen bedingte 
 Entwickelungshemmungen des Kaninchengehirns. — Arch. f. Psychiatric, Bd. 
 xii, Heft I. 
 
 Weitere Mittheilungen liber durch Extirpation circumscriptar Hirnrinden- 
 region bedingte Entwickelungshemmungen des Kaninchen. — Idem, Heft 3.
 
 28 E. C. SEGUIN. 
 
 the thalamus of the same side was smaller. He also ad- 
 mits that Luys has for some time taught that definite re- 
 gions of the cortex stood in relation to definite portions or 
 nuclei of the thalamus, but this from pure theory. 
 
 After a few experiments on kittens, he was obliged, be- 
 cause of great mortality, to use rabbits, which he did with 
 regret, because of their slight intelligence (compare Gudden 
 and Ganser, whose rabbits seemed normal after removal of 
 one hemisphere). 
 
 ExPT. I. — A portion of cortex and white substance of right hemi- 
 sphere was removed from the parietal gyrus near the longi- 
 tudinal fissure. This region M. considers to be just caudad of 
 Ferrier's and Ftirstner's area No. 6 (see fig. i) ; about equivalent 
 to Hitzig's No. I area in dogs and monkeys ; and also to Munk's 
 centre for the leg. Caudad and laterad of extirpated region are 
 Munk's region for the sensibility of the eye, and further his visual 
 sphere. The extirpated zone is marked a in fig. i. 
 
 Results : The nucleus externus of right thalamus is totally atro- 
 phied. Right corpus geniculatum laterale much atrophied, chiefly in 
 its caudal portion. Right trapezium, pyramid, and lateral lemniscus 
 a little smaller than their homologues. A part of the internal cap- 
 sule in relation with the wound is atrophied. The lateral part of 
 the crus cerebri is small, and the formatio reticularis reduced. 
 
 ExpT. 2. — Removal of a portion of left occipital lobe (A. in fig. 
 i). Considers spot injured as equivalent to Ferrier's and Fiirst- 
 ner's centre No. 9, and to Munk's area A, the visual sphere of the 
 dog. 
 
 Results : Slight atrophy of medullary substance near cicatrix, 
 of caudal part of left internal capsule ; great atrophy of left corpus 
 geniculatum laterale and of tractus opticus, of left tractus pedun- 
 cularis transversus, of the outer part of the nucleus externus of the 
 thalamus. The left lobus opticus is slightly flattened ; the right 
 optic nerve a little smaller than its fellow. 
 
 Conclusions: The atrophy extended from the visual 
 sphere to the corpus geniculatum laterale and slightly to 
 the rest of the optic apparatus ; it was in inverse degree 
 to what follows enucleation of the eyeball. The corpus 
 geniculatum laterale is, therefore, a centre for vision in
 
 GUDDEN 'S A TROPHY METHOD. 
 
 29 
 
 association with the cortical centre ; the outer part of the 
 nucleus externus which the author considers equivalent to 
 the pulvinar,' is also a part of the optic apparatus. 
 
 V £ 
 
 The second article contains the following numerous ex- 
 periments : 
 
 ' Forel has shown that the lower mammals have no true pulvinar. 
 
 Monakow adds some remarks on the nomenclature of the nuclei of the thala- 
 mus, and follows Ganser's (Gehirn der Maulwurfs, Morphol. Jahrbuch, Bd. 
 vii, p. 711) arrangement, into nucleus anterior (tuberculum anterius), nucleus 
 internus, nucleus externus, and nucleus posterior. 
 
 ^ Explanation of cuts in the original articles. 
 
 Fig. I. — Right hemisphere slightly modified from Monakow. 
 
 A. Zone of corp. gen. ext. 
 
 B. Zone of corp. gen. int. 
 
 a. Zone of optic thalamus. 
 
 b. Zone of stratum reticulare. 
 d. Zone d. 
 
 ^andy. Zone of nucleus internus. 
 
 On the left hemisphere are placed the motor centres of Ferrier, as depicted in 
 Fiirstner's article, WestphaVs Archiv, vol. vi, p. 725. 
 
 1. Raising of upper lip ; rotation of head to right. 
 
 2. Drawing of mouth to right ; masticatory movements on right ; drawing of 
 head to right. 
 
 3. The same. 
 
 4. Raising the right shoulder ; extending the toes. 
 
 5. Retraction and adduction of the right paw ; extension of toes. 
 
 6. Epileptic seizure. 
 
 7. Masticatory movements with the right upper lip and jaws ; drawing of 
 the head toward the left. 
 
 8. Shutting the eyes. 
 
 9. The same. 
 10. Indefinite. 
 
 Fig. 2. — Profile view of right hemisphere of figure I.
 
 30 E. C. SEGUIN. 
 
 ExPT. I. — Removal of zone b, fig. i. Results : Atrophy of part 
 of internal capsule (its third fifth about), extending from the 
 wound centrally ; of nervous tissue lateradof the nucleus anterior 
 of the thalamus (not atrophied). A slight atrophy of the corpus 
 geniculatum laterale M. thinks is due to encroachment of lesion 
 upon zone a. The lateral part of the crus cerebri is slightly re- 
 duced in size. Considers the part most atrophied in this experi- 
 ment, the lateral adjunct to the nucleus anterius as the stratum 
 reticulare (frontal part of Gitterschichi). Zone b is therefore the 
 centre for the stratum reticulare. 
 
 ExPT. 2. — Extirpation of zone B. This area occupies the 
 greater part of the temporal lobe, and corresponds with Munk's 
 auditory sphere B in dogs and monkeys. Results : Atrophy of 
 connected fasciculus of corona radiata and internal capsule 
 (caudo-ventral part), and of the corpus geniculatum mediale. 
 There is also slight atrophy of the caudal part of the stratum 
 reticulare [Gitterschicht). No changes could be detected in the 
 acoustic nerve and its nucleus. 
 
 Conclusion : Zone B is the centre for the corpus genicu- 
 latum mediale. Query: Is the corp. gen. med. a primary 
 centre for hearing as the corp. gen. lat. is for vision ? 
 
 ExPT. 3. — Extirpation of extreme frontal end of hemisphere 
 / and a part of e in fig. i. Results : Atrophy of basal part of cap- 
 sula interna, without and within the corpus striatum, and of a part 
 of the nucleus internus. Corpus striatum preserved. Pyramidal 
 tract partly atrophied. 
 
 ExpT. 4. — Removal of zone d, including some of b. Results : 
 Atrophy of corresponding part of internal capsule, and of caudal 
 part of stratum reticulare. 
 
 ExPT. 5. — Extirpation of area including c, d, e. These zones 
 are frontad of a and b, and include nearly all the motor centres of 
 Ferrier and Furstner : its medial part corresponds to the para- 
 central lobule. Results : Atrophy of dependent fasciculi of in- 
 ternal capsule, without and within the corpus striatum (which is 
 normal) ; atrophy of tuberculum anterius (nucleus anterius) to 
 one half its normal size, an atrophy equally distributed in its 
 two cell-groups. Thence the atrophy can be followed in two 
 paths, separated by normal fibres coming from other parts of the 
 brain : {a) The ventral atrophy involves the pyramidal tract 
 (medial part of crus cerebri) ; the corresponding pyramid is al-
 
 G UDDEN 'S ATR OPH V ME THOD. 3 I 
 
 most totally atrophied, and the opposite half of the spinal cord 
 contains the well-known crossed pyramidal atrophy. The corpus 
 Luysii and the substantia nigra on the side of the injury are re- 
 duced in volume. {J)) The dorsal atrophy expands into the area 
 made up partly by the stratum reticulare, and by the laminae 
 medullares ext. The nucleus internus is slightly atrophied. The 
 fasciculus Vicq D' Azyr is small, but not reduced in a degree cor- 
 responding with the atrophy of the nucleus anterius, Still an- 
 other atrophy is produced by this operation, viz.: that of a longi- 
 tudinal fasciculus in the white substance of the hemisphere, in its 
 dorsal part, extending to the occipital lobe (fasciculus longitudi- 
 nalis superior). Areas c, <?,/" constitute a pyramidal zone. 
 
 Monakow also extirpated five smaller areas in a, and separately 
 the areas c, d, e. The results agreed with those obtained by ex- 
 periments detailed above. Altogether more than fifty experiments 
 were made. 
 
 Summary : If we associat^the cortical zones with those 
 central nuclei which were most atrophied by their extirpa- 
 tion, we have the following list : 
 
 Zone A, or visual sphere, is related to the corpus genicu- 
 latum laterale. 
 
 Zone a is related to the nucleus externus. 
 
 Zone b is related to the stratum reticulare. 
 
 Zone B is related to the corpus geniculatum mediale. 
 
 Zones c, d, e are related to the nucleus anterior and 
 nucleus internus. 
 
 Zones c, e, f are related to the pyramidal tract. 
 
 It is observable that the nucleus posterior does not suffer 
 in any of these experiments : very probably it is connected 
 with strictly basal parts of the cortex. 
 
 Monakow believes, in consequence of these experiments, 
 that each cortical area or zone is connected with more 
 than one path or tract. 
 
 That the various nuclei of the thalamus as well as the 
 corpora geniculata stand in definite relations to circum- 
 scribed cortical areas. 
 
 That the corpora geniculata medialis et lateralis are ana-
 
 32 E. C. SEGUIN. 
 
 loeues of the nuclei of the thalamus and should be con- 
 sidered as associated with them. 
 
 XVI IT. — Connections of the cortical visual area with the optic 
 
 apparatus. 
 
 ExPT. ' I. — In a newly-born kitten removal of a large part 
 of the parietal cortex and the subjacent white substance on one 
 side. Autopsy in six months. Results : Sections frontad of 
 wound show great atrophy of cortex of motor gyri and of the un- 
 derlying white substance on the same side as the injury. Micro- 
 scopic examination shows that the atrophy bears chiefly upon the 
 third layer of cells in the cortex, that containing the larger gang- 
 lion cells (giant-cells of Betz) ; these are entirely absent. Sec- 
 tion in the injured region ; the corpus striatum is normal, but the 
 fasciculi of the internal capsule which normally traverse it are 
 absent,^ except the ventral bundle derived from the lobus olfac- 
 torius. The optic nerve of the same side is smaller (its trans- 
 verse diameter is less) than its fellow ; this being due, in Mona- 
 kow's opinion, to absence (atrophy) of the fasciculus lateralis, 
 which has a connection with the cortical visual area (encroached 
 upon by the wound). Further caudad the tractus opticus is 
 smaller on the operated side ; the tuberculum anterius (nucleus 
 anterior) of the thalamus is wholly atrophied. The commissura 
 anterior and the temporal lobe are normal. The nucleus externus 
 thalami is almost wholly atrophied, while the nucleus internus is 
 preserved. The part dorsad of the corpus geniculatum lat., 
 which M. holds to be the equivalent of the human pulvinar, is 
 fairly preserved. The corp. genie, lat. itself is somewhat re- 
 duced, but the mediale is normal. The lobus opticus on the in- 
 jured side is smaller than its fellow, having suffered atrophy in 
 its middle medullary layer. The medial part of the crus cerebri 
 is much atrophied, and the lemniscus less developed on the in- 
 jured side. The fasc. Vicq d'Azyr and medial ganglion of the 
 corpus mammillare are partly atrophied. In the tegmentum 
 there is absence of the pyramidal tract and diminution of the 
 lemniscus. In the caudal part of the pons there isno pyramid on 
 the side of injury, but the slight atrophy of the lemniscus gradu- 
 ally ceases. 
 
 ' Experimentelle Untersuchungen iiber umschriebene Hirniindenatrophien. 
 Vortrag gehalten an der 56 Versammlung Deutscher Naturforscher und Aerzte. 
 Freiburg, Sept., 1883. 
 
 * Von Gudden obtained a similar result in his experiment of removal of the 
 motor gyri, vide p^
 
 GUDDEN'S A TROPH Y ME THOD. 3 3 
 
 ExPT.' 2. — In a newly-born rabbit, a simple oblique stabbing 
 wound was made with a narrow knife in the temporal lobe, in a 
 medio-ventrad direction. Autopsy in three and a half weeks. 
 It was found that the caudal part of the internal capsule (Grati- 
 olet's optic fasciculus), its connection with the corpus geniculatum 
 mediale, and the tractus opticus, had been divided ; the crus 
 cerebri very slightly injured. 
 
 Results : Sections through the brain frontad of the injury 
 showed the cortex normal, but its internal capsule less developed ; 
 caudad of the injury, in the occipital lobe there is marked atrophy 
 of the cortex and white substance, due to section of the internal 
 capsule. There is complete atrophy of the corpus geniculatum 
 laterale (greater than can be accounted for by section of the 
 tractus opticus). The lobus opticus on the same side as the injury 
 is distinctly smaller. The corp. genie, mediale is completely 
 atrophied from section of the fibres connecting it with the internal 
 capsule. The various nuclei of the thalamus are normal. Micro- 
 scopic examination of the atrophied occipital cortex showed that 
 the atrophy affected mainly the third layer, or layer of large 
 ganglion cells ; they were entirely absent. The cells of the fifth 
 layer were slightly reduced. In the small lobus opticus it is seen 
 that the atrophy bears chiefly upon the superficial medullary 
 layer, whose cells are fewer and smaller. After removal of the 
 visual area alone (B in fig. i), the atrophy of the lobus opticus is 
 not of these cells, but is most marked in the middle medullary 
 layer. In the above-detailed experiment there is also some 
 atrophy of this layer, because a part of the optic fasciculus going 
 to the cortex was injured. The atrophy of the superficial medul- 
 lary layer is, however, much greater than after enucleation of one 
 eyeball. 
 
 The results of these experiments^ Mo7iakow s first and second 
 set of experiments upon the relations of the cortex and the 
 thalamic nuclei {including the corpora geniculatd). 
 
 What is mo^^ important, and what, if confirmed, will 
 form an epoch in this department of experimental physi- 
 ology, is the production of an ascending (centripetal) 
 atrophy of the cortex by section of fasciculi of the internal 
 
 ' Ueber die Ursprungscentren des Nervus Opticus, iind deren Beziehungen 
 zur Grosshirnrinde. Vortrag gehalten an der 66 Versammlung der Schweizer- 
 ischen Naturforschenden Gesellschaft, Zurich, August, 1883.
 
 34 E- C. SEGUIN. 
 
 capsule. It will be remembered that both Gudden and 
 Monakow (see corpus restiforme) have shown that after 
 section of the pyramidal tract low down (caudad) there 
 was no ascending (centripetal) degeneration, or at most 
 only in a very slight degree for a millimetre or two. 
 But in both the last experiments section of the internal 
 capsule (in expt. i its frontal division, in expt. 2 its 
 occipital division) caused distinct atrophy of the associated 
 cortical regions, in which mainly the third cell-layer (that 
 of giant-cells) was atrophied. 
 
 The first experiment also corroborates Gudden's finding, 
 that the corpus striatum has no corona radiata. 
 
 Another important result (of expt. i) is the apparent dem- 
 onstration that there is a degree of anatomical continuity 
 between the cortical visual area and the optic nerve (its 
 fasciculus lateralis). This is in opposition to von Gudden's 
 results. 
 
 The general agreement between the results of physi- 
 ologists (Munk, Hitzig, Ferrier, and others) and those 
 of von Monakow is striking, and affords supplementary 
 evidence of their approximate exactness. 
 
 Dr. von Monakow has recently made an autopsy of 
 a human case ' which strongly supports his and Munk's ex- 
 periments on the visual cortical area. 
 
 There was in this case an old (probably five years old, judging 
 by the imperfect history of the case) yellow patch (softening due to 
 blockade of branches of the right posterior cerebral artery) in the 
 right occipital lobe, more especially destroying the cuneus. Pre- 
 vious to the patient's reception in the asylum he had had " imper- 
 fect vision," which was explained by finding homonymous hemi- 
 anopsia. In sections, one can trace, in the clearest manner, a band 
 of degeneration from the patch in the occipital division of the in- 
 ternal capsule (Gratiolet's optic fasciculus) frontad and mediad to 
 the corpus geniculatum laterale and pulvinar. The pulvinar is al- 
 
 * Unpublished.
 
 G UDDEN ' S A TROPH V ME THOD. 3 5 
 
 most entirely atrophied, and the corp. genie, lat. largely so ; its folds 
 are absent. The crus of the lobus opticus (brachium) is also in 
 a state of secondary degeneration (granular cells, excessive stain- 
 ing by carmine). These changes border closely on the corp. 
 genie, mediale which is normal, a fact which speaks positively 
 against a primary disease here (besides the blood-vessels of this 
 region were healthy). The lobi optici are equal and present no 
 changes to the naked eye, but microscopic examination shows 
 that in the right lobus the middle medullary layer {inittleres 
 Mark of Ganser) contains fewer and smaller cross-cut bundles 
 of nerve fibres. The atrophy is about the same as in Ganser's 
 rat B {vide p. 142 of Archives for October). The lateral and 
 medial parts of the lemniscus are smaller on the side of the 
 lesion. It should be stated that further frontad the lateral part of 
 the corp. genie, lat. is completely atrophied, while its medial part 
 is preserved ; von Monakow is disposed to conclude that the 
 former is connected with the cuneus, while the latter receives its 
 innervation from the rest of the visual cortical area. 
 
 The tractus opticus on the side of the lesion is much re- 
 duced in size. Beyond the chiasm, the atrophy is traceable 
 in both optic nerves ; the degenerated part standing out clearly 
 marked by an excess of carmine. The right optic nerve exhibits 
 a patch of degeneration in its lateral aspect (fasciculus later- 
 alis ; the left nerve, in its medial aspect (fasciculus cruciatus). 
 
 XIX. — Connections of the optic nerve with the ^'■primary 
 optic centres!' ' 
 
 ExPT. I. — In a newly-born rabbit, one eyeball was enucleated. 
 Autopsy after one year. Results : Complete atrophy of injured 
 optic nerve ; atrophy of tractus opticus on the opposite side of its 
 fibres overlying the corp. geniculatum lat. Also atrophy of this 
 nucleus, more especially in its lateral part. Microscopic examina- 
 tion shows that this atrophy affects the fundamental or inter- 
 cellular substance, and that the peculiar globular cells are about 
 as on the normal side, only very much closer together. The lobus 
 opticus is somewhat smaller on the side opposite the injury, and 
 microscopic examination shows that the atrophy involves both 
 cells and fibres in the superficial medullary layer {oberfldchliches 
 Mark of Ganser). No change in the cortex cerebri. In consid- 
 ering this experiment it should be borne in mind that in the rab- 
 bit the optic nerves almost totally decussate. 
 
 ' Unpublished.
 
 3^ E. C. SEGVIN. 
 
 ExPT. 2, — In a newly-born kitten, one eyeball wa^ enucleated. 
 Autopsy in three months. Results : Complete atrophy of injured 
 optic nerve ; both tractus optici are smaller than normal, the one 
 opposite the lesion a little flatter than its fellow. [The optic dec- 
 ussation in cats is considered by M. to be nearly equal.] Both 
 corpora genie, lat. are smaller, as are also the adjacent regions 
 equivalent to the pulvinar. The streaks normally present in the 
 Corp. genie, lat. are absent, and the lateral aspects of the pulvinars 
 exhibit an atrophic indentation. The lobi optici are about equally 
 reduced in size, and microscopic examination shows the atrophy 
 to bear chiefly upon the superficial medullary layer (Ganser's ober- 
 fldchliches Mark), mostly in its fibres, but also somewhat in its 
 ganglion cells. 
 
 I cannot close this review without expressing my appre- 
 ciation of the courtesy with which Doctor von Monakow 
 received me at St. Pirminsberg, and the pains he took to 
 demonstrate all his preparations. He, as well as Professor 
 von Gudden, have allowed me to make use of unpublished 
 material, and its appearance in the Archives OF MEDICINE 
 is to be considered as preliminary original communications 
 from these gentlemen. 
 
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