LIBRARY 
 
 OF THE 
 
 UNIVERSITY OF CALIFORNIA. 
 
 BIOLOGY 
 
 Class LIBRARY, 
 
 6 
 

LECTURES 
 
 ON 
 
 LOCALIZATION 
 
 IN 
 
 DISEASES OF THE BRAIN 
 
 DELIVERED AT THE FACULTE DE MET>ECINE, PARIS, 1875 
 
 BY 
 
 J. M. CHARCOT 
 
 Professor in the Faculty of Medicine of Paris ; Chief of the Salpetriere Hospital; 
 
 Member of the Acadhnie de Midecine ; of the Clinical Society of London ; 
 
 President of the Sociite Anatomique ; former Vice-President 
 
 of the Societe de Biologie, etc.. etc. 
 
 EDITED 
 
 BY 
 
 BOURNEVILLE 
 
 TRANSLATED BY 
 
 EDWARD P. FOWLER, M.D. 
 
 OF THE 
 
 UNIVERSITY 
 
 OF 
 
 NEW YORK 
 
 WILLIAM WOOD & CO., 27 GREAT JONES ST. 
 
 1878 
 
.BIOLOGY 
 RA 
 G 
 
 COPYRIGHT BY 
 
 WILLIAM WOOD & CO., 
 1878. 
 
 TROW'S 
 
 PRINTING AND BOOKBINDING Co. 
 205-213 East \-ith St., 
 
 NEW YORK. 
 
AUTHOR'S PREFACE. 
 
 THE exposition of the principles underlying the doctrine 
 of cerebral localization seems to have now become a neces- 
 sary chapter of introduction to the practical study of diseases 
 of the brain. 
 
 In the Lectures which Dr. Fowler has kindly taken the pains 
 to submit to the appreciation of our American confreres, I 
 have selected, as occasion required, information furnished by 
 normal anatomy, experimental physiology, and clinical ob- 
 servation, illustrated by minute and methodical examination 
 of organic lesions. 
 
 I have always given precedence, however, to the last- 
 mentioned order of testimony, convinced that, although 
 normal anatomy and experimental physiology may serve to 
 indicate the true direction ; still, clinical and pathological 
 research is necessary (in case of the human subject) to a final 
 judgment and to the furnishing of proof . 
 
 I shall consider it as a great honor if my book should be 
 favorably received in a country where instructors in neural 
 pathology are represented by scientists such as my friend 
 W. Mitchell, and various others whom I might enumerate. 
 
 202754 
 
iv AUTHOR'S PREFACE. 
 
 In any event, I cannot sufficiently thank Dr. Fowler for 
 the care which he has bestowed upon the translation, and I 
 unhesitatingly say that it appears to me a model, both of 
 scrupulous exactitude in rendition of the original meaning, 
 and as a clear and unexceptionable style of English. 
 
 J. M. CHARCOT. 
 
 PARIS, Oct. 26, 1878. 
 
TRANSLATOR'S PREFACE. 
 
 No excuse is required for contributions to medical litera- 
 ture which are calculated to increase exactitude of expres- 
 sion, ideas, and knowledge, thereby assisting to elevate 
 medical Art to the higher plane of Science. 
 
 These lectures are a bold example of that cast, as in- 
 deed are all of Charcot's teachings and writings. 
 
 It is too late to introduce our distinguished author to 
 the medical profession, for wherever medicine is taught 
 as a science his works are already known and prized, and 
 have been translated into nearly every modern language. 
 This, however, is the first volume which has been pub 
 lished in this country. 
 
 Charcot's superstructures are always built with great 
 care and reserve upon the secure basis of induction, though 
 he is none the less resplendent in the rich harvest of de- 
 duction which naturally follows. 
 
 The translator cannot refrain from expressing his con- 
 viction that the perfecting of medical knowledge depends 
 mainly upon those investigators of which Charcot is so 
 brilliant and so sound a representative. 
 
 NEW YORK, July, 1878. 
 
CONTENTS 
 
 FIRST LECTURE. 
 
 PAGE 
 
 Localization in Cerebral Diseases . . i 
 
 SECOND LECTURE. 
 Structure of the Gray Substance of the Brain 14 
 
 THIRD LECTURE. 
 
 Considerations upon the Normal Structure of the Gray Substance 
 
 of the Convolutions 24 
 
 FOURTH LECTURE. 
 Parallel between Spinal and Cerebral Lesions 33 
 
 FIFTH AND SIXTH LECTURES. 
 Arterial Circulation in the Brain 41 
 
 SEVENTH LECTURE. 
 
 Circulation in the Central Masses (Gray Ganglia and the Internal 
 
 Capsule) 59 
 
 EIGHTH AND NINTH LECTURES. 
 Central Arteries. Isolated Lesions of the Gray Ganglia 70 
 
viii CONTENTS. 
 
 TENTH LECTURE. 
 
 PAGE 
 
 Cerebral Hemianaesthesia (Continued). Crossed Amblyopia. Lat- 
 eral Hemiopia 90 
 
 ELEVENTH LECTURE. 
 Origin of the Cerebral Portion of the Optic Nerves 101 
 
 TWELFTH LECTURE. 
 Secondary Degeneration 115 
 
OF THE 
 
 UNIVERSITY 
 
 OF 
 
 LECTURES UPON LOCALIZATION 
 
 IN 
 
 DISEASES OF THE BRAIN, 
 
 FIRST LECTURE. 
 
 LOCALIZATION IN CEREBRAL DISEASES. 
 
 Summary : Preamble. Apparent Aridity of the Study of Cerebral 
 Localization. Principles of Localization. The Encephalon in a 
 Morphological Point of A' lew. Necessity of an Exact Nomenclature. 
 Topography of the Convolutions. Importance of Comparative 
 Anatomy. Convolutions of the Brain of the Monkey; Frontal, Pari- 
 etal, and Sphenoidal Lobes. Psycho-motor Centres. Differences in 
 the Composition of the Gray Substance in the Various Regions of 
 the Brain. 
 
 GENTLEMEN : 
 
 I. We will devote the first part of this year's course to 
 the anatomico-pathological study of the encephalon. Every 
 one in an audience of medical practitioners will recognize the 
 importance of this subject. But, with some, the lack of an 
 attractive exterior has given it an unfortunate reputation.; 
 in this particular I hope to inspire you with a different sen- 
 timent. Through a method already often employed, aided 
 also by a certain amount of patience and perseverance and 
 that will not be lacking on my part, I assure you I think 
 we shall accomplish this task without undue fatigue or diffi- 
 culty. 
 
 To avoid leading you unprepared into the domain where 
 
2 DISEASES OF THE BRAIN. 
 
 we shall journey together, I will make, by way of an intro- 
 duction, some observations concerning general facts, the ap- 
 plication of which facts will be obvious at each subsequent 
 step. 
 
 I have little faith in the value of generalities when unac- 
 companied by their material substructure, and especially as 
 concerns pathological anatomy. I will therefore supply such 
 groundwork by furnishing a certain number of actual illustra- 
 tions. These examples will be taken from the most impor- 
 tant chapter in encephalic pathology, that treating of locali- 
 zation in cerebral diseases. 
 
 Various reasons have decided my choice of subject. In 
 the first place, it is one of those fields of inquiry where the 
 advantage of associating clinical with anatomico-pathological 
 studies is most conspicuously evident ; upon the principles of 
 cerebral localization is founded that which may be called 
 regional diagnosis of encephalic diseases, that ideal toward 
 the realization of which, in this special section of pathology, 
 should be directed all the efforts of clinical teaching. 
 
 Then, again, the question of cerebral localization has en- 
 tered a new phase, and is now enlisting world-wide attention. 
 
 We should not make undue sacrifices to fashion, but on 
 the other hand we must not undervalue the attractions and 
 the new facts presented by recent investigations. 
 
 In a thesis offered at the last conconrs ^aggregation de 
 medecine, this interesting chapter has been handled with 
 great ability by my friend and old pupil, Dr. Lepine, agrege 
 of that faculty. I shall be happy to utilize the delicately dis- 
 criminated observations which abound in that work, and to 
 turn to profit the wealth of erudition which the author has 
 there accumulated. 
 
 It is understood, of course, that in these preliminary lectures 
 we can give only a free outline. The subjects which I shall 
 introduce should be resumed later, submitted to a more pro- 
 found study, and examined in their most minute details. 
 
 II. Long explanations are unnecessary to convey what is 
 meant by localization in cerebral physiology and pathology. 
 
LOCALIZATION IN CEREBRAL DISEASES. 3 
 
 The term has long since become a common one, and its 
 meaning is well known. I will therefore only remind you 
 that the principles of cerebral localization rest upon the fol- 
 lowing proposition : The encephalon does not represent an 
 homogeneous organ, a unit, but rather an association, or a 
 confederation, composed of a certain number of diverse 
 organs. To each of these organs belong distinct physio- 
 logical properties, functions, and faculties. Now, the physio- 
 logical properties of each one of these parts being known, it 
 becomes possible to deduce therefrom the conditions of a 
 pathological state ; this being of course but a greater or less 
 modification of the normal state, and not a result of the inter- 
 vention of new laws. 
 
 We will employ the varied knowledge furnished by normal 
 anatomy and experimental physiology, together with those 
 clinical observations which have been rendered reliable by a 
 methodical and minute examination of organic lesions, and 
 thus endeavor to ascertain upon what foundation this propo- 
 sition rests. The importance and the decisive results which 
 depend upon these last-named examinations cannot be over- 
 stated. For although normal anatomy and experimental 
 physiology may often suggest the true direction towards 
 localization, still nothing but the actual examination of organic 
 lesions will permit a final decision and furnish the proof, at 
 least so far as concerns the special subject of our studies man. 
 
 A. This brings us to an examination of the encephalon 
 under its morphological aspect. It is understood we do not 
 attempt a rigorous description ; I propose only to draw a 
 general outline, a knowledge of which is indispensable to our 
 object. To simplify a very complex situation, I will confine 
 myself to the brain ; that is, to that mass of nervous substance 
 composed of two hemispheres and situated at the superior 
 extremity of what are called the cerebral peduncles (crura 
 cerebri). 
 
 The two hemispheres are nearly symmetrical, and so nearly 
 identical in their structure that whatever may be said of the 
 one may, anatomically speaking, rigidly apply to the other. 
 Each one is enveloped in a layer of gray substance. The 
 
DISEASES OF THE BRAIN. 
 
 central part is formed by a mass of white substance, in which 
 are furrowed the ventricles, and where are also seen, as if 
 locked together, the central ganglionic masses, namely, the 
 thalami optici and the corpora striata. 
 
 A transverse section made to intersect the corpora mammil- 
 laria best demonstrates the main features of the reciprocal 
 relations of the central parts. (Fig. i.) 
 
 Lenticular ftud 
 
 Horn of Anirnon 
 
 Sphenoidal Horn 
 of lat. Ventricle 
 
 Post, ceretral Arteries 
 
 FIG. i. Vertico-transverse section of the brain, posterior to the tubercula mam- 
 millaria ; anterior to the peduncles. 
 
 Immediately above the protuberance you see the inferior 
 face of the crura cerebri, the inferior portions of which issue 
 mainly from the anterior bulbs of the pyramids. 
 
 From the lower up to the middle part of the section, you 
 
LOCALIZATION IN CEREBRAL DISEASES. 5 
 
 will see two large, white tracts which run divergingly towards 
 the cortical portions of the hemispheres. They are between 
 two masses of gray substance, the one internal and superior, 
 the other external and inferior. These two tracts are the pro- 
 longations of the crura cerebri to the cerebral hemispheres. 
 
 The crura cerebri, which are at first irregularly quadrilateral, 
 become horizontally flattened as they enter the hemispheres, 
 running from behind forwards, and when they have passed 
 the narrow strait of the ganglionic region they open and 
 spread in every direction in front towards the frontal ex- 
 tremity, in the centre towards the parietal regions, behind 
 towards the occipital extremity. Burdach calls the flattened 
 interganglionic parts of the peduncles the internal capsules ; 
 the subsequent expansion has been called by Reil the cou- 
 ronne rayonnante, diverging fibres ; the foot of the diverg- 
 ing fibres is where the peduncles emerge above the cerebral 
 ganglia. The peduncles as they enter the hemispheres some- 
 what resemble a spread fan. 
 
 Let us now describe briefly returning to it later the re- 
 spective locations of the cerebral ganglia in regard to this fan. 
 
 When, upon making the classic section, the lateral ventri- 
 cles were opened, you will remember that there protruded 
 upon the surface two masses of gray substance ; the anterior 
 and external one is shaped like a comma or a glass tear, the 
 large extremity or head of which is anterior and the small 
 end or tail (cue) is posterior and lateral, and is. called the 
 nucleus caudatus of the corpus striatum ; the other mass is 
 internal and posterior, and is ovoid this is the thalamus opti- 
 cus ; the thalami optici arc separated by the base of the third 
 ventricle. 
 
 These two intraventricular gray masses, the nucleus cau- 
 datus of the corpora striata and the thalami optici, rest 
 above and within the peduncular fan. Below the fan, and 
 more voluminous than the other two, is found a third nucleus 
 having much the form of a plano-convex lentil, from whence 
 the name, lenticulares glandules (Burdach). 1 As it is of 
 
 1 In French nomenclature it is called the extra ventricular nucleus of the 
 corpus striatum. 
 
6 DISEASES OF THE BRAIN. 
 
 equal extent antero-posteriorly with the other two, it will 
 always be found upon transverse sections (frontal sections of 
 the Germans), perpendicular to the great interhemispheric 
 fissure, whenever the others are met with. 
 
 The study of transverse sections, made at methodical inter- 
 vals from before backward, and commenced from certain 
 starting-points upon the base of the hemispheres, is indispen- 
 sable to a familiarity with the mutual relations of the ganglia, 
 as well as their relations to the peduncles, and it is also 
 essential to the clinicien, whose duty is to precisely deter- 
 mine the parts diseased. 
 
 I will describe, as our studies may require, the appearance 
 of these transverse sections. An understanding of one of 
 the most posterior of these sections, made immediately in 
 front of the crura cerebri (Fig. i), is all that we need at the 
 present moment. 
 
 You here see the flattened portions of the crura, the inter- 
 nal capsules. Within these are seen the surfaces of the thai- 
 ami optici and the queues of the corpora striata. To the 
 outer side of the internal capsule is seen, with its three seg- 
 ments, the lenticular nucleus of the corpus striatum. These 
 gray nuclei are possibly so many centres endowed with dis- 
 tinct properties and functions ; but it must be remembered 
 that this is not yet positively demonstrated. Still external 
 to the lenticular bodies you will discover, in succession, the 
 external . capsules, the outer walls (little white unnamed 
 bands), and lastly the gray layers of the island of Reil. 
 
 I have no intention to engage at present with details of 
 structure ; I wish only to insist upon these designations 
 given, however minute they may seem ; for years past I 
 have persisted in introducing them into the French nomencla- 
 ture only because I have considered them of the highest 
 utility when, as upon autopsy, it is desirable to indicate the 
 exact locality of the lesion. Who would dare to affirm that 
 such or such a region, which has no place in our nomencla- 
 ture, is not possessed of an importance even of the first 
 order ? Besides, how can such region be described in a 
 record of autopsy if it has no recognized name ? The names 
 
LOCALIZATION IN CEREBRAL DISEASES. / 
 
 which I supply furnish many starting-points, and their utility 
 is therefore incontestable. Is a good strategic chart ever too 
 complete ? It is in thus precisely specifying the spot occu- 
 pied by a hemorrhagic centre the external or internal cap- 
 sules, the gray ganglia, the foot of the diverging fibres, etc. 
 that you will be able to prove whether there are symptomatic 
 differences of location such as might aid prognosis. An 
 example, presented in a case of cerebral haemorrhage, will 
 serve as proof that this is no superfluous labor. If a haem- 
 orrhagic centre involves only the external capsule, what- 
 ever be the extent of the lesion, the patient in all probability 
 will recover without persistence of hemiplegia or any other 
 infirmity ; but, on the contrary, if it be the internal capsule 
 that is involved, and the patient survives, there will remain 
 persistent paralysis and permanent contractions. 
 
 The importance of an exact and minute study of the shape 
 and plan of the brain, joined to an appropriate nomenclature, 
 is especially shown when dealing with the convolutions upon 
 the surface of hemispheres. For a long time these convolu- 
 tions were supposed to be, as it were, the result of chance, 
 and thus they escaped any close description. Leuret and 
 Gratiolet demonstrated that, on the contrary, there was an 
 orderly plan, which could be traced from the inferior mam- 
 malia, by the way of the monkey, up to man. 
 
 Moreover, there are among the convolutions those which 
 can be called fundamental, for the reason that their locations 
 and relations are absolutely fixed ; then again there are those 
 which may be termed secondary, or accessory, and which 
 must be studied abstractly, because they are variable. 
 
 You will easily comprehend that without a good topog- 
 raphy of the convolutions it is quite impossible to take one 
 step in the more important knowledge of cerebral localiza- 
 tions. For example, how can we speak of lesions produc- 
 ing aphasia unless we are able to determine precisely the 
 location and form of the third frontal convolution ? How 
 could we locate in man the regions called psycho-motor, 
 which the studies of Fritsch, Hitzig, and Ferrier have discov- 
 ered in animals, if no notice be taken of the convolutions and 
 
8 DISEASES OF THE BRAIN. 
 
 furrows upon the gray substance of the parietal lobes and the 
 posterior portions of the frontal lobes ? How many observa- 
 tions which might have thrown light upon these interesting 
 questions of localization are valueless, for the reason that, 
 from an insufficient knowledge of the altered parts, an exact 
 description has not been possible ! In order to obviate as 
 far as possible that lack in the anatomical description of the 
 normal brain, I have for a long time past habituated myself 
 to outlining the locations of brain-lesions upon schemes de- 
 signed from nature. In the absence of these precautions 
 no ideas can be obtained which are not open to criticism. 
 Still, this study has not so many difficulties as may at first be 
 supposed. If the most complete knowledge has not yet found 
 its way into classic works, it nevertheless abounds elsewhere. 
 Beyond the standard works of Leuret and Gratiolet, BishofT, 
 Arnold, Turner, etc. (a familiarity with which is indispen- 
 sable), I recommend to your use the little manual of Ecker, 1 
 which contains good topographical plates, accompanied with 
 a simple nomenclature, together with synonyms. Through 
 my advice Duret has employed these plates in his important 
 memoire upon the circulation in the encephalon. An excel- 
 lent work upon this subject, also, is a thesis by Gromier, written 
 under the inspiration of Paul Broca, and entitled, " Study 
 upon Cerebral Convolutions in Man and Monkey. 1874." 
 
 Comparative anatomy is also a powerful adjunct in the 
 study of the convolutions. Between the monkey and man, 
 for example, the resemblance is striking, 2 as concerns the fun- 
 damental convolutions and furrows, and that arrangement, 
 which in man is somewhat unintelligible, is explained in the 
 brain of the monkey by reason of its greater simplicity. I 
 therefore will exhibit a sketch of the convolutions as ob- 
 served in the monkey before considering those of the human 
 
 1 Die Hirnwindnngen des Men re hen nach eigenen Untersuchungcn insbesondere 
 iiber die Entwicklung derselben beim Fotus und mit Rucksicht auf das BedUrf- 
 niss der Arzte. Brunswick, 1869. There is an English translation of the work. 
 
 * Upon this subject, read in the last edition of Darwin's " The Descent of 
 Man" (London, 1874), Professor Huxley's interesting note (p. 199), on the resem- 
 blances and differences in the structure and development of the brain in man and 
 apes. 
 
LOCALIZATION IN CEREBRAL DISEASES. 
 
 brain. This study possesses additional interest from the fact 
 that actual experiment has already located upon some of the 
 convolutions of the monkey brain those points known as psycho- 
 motor, thus furnishing a base for clinical and anatomico-patho- 
 logical research concerning their existence in corresponding 
 points of the human brain. 
 
 Here is a lateral representation of a monkey's brain (Fig. 2) 
 
 . 
 
 IKoIor-cenlers for rotation. 
 of head&.neck 
 
 Motor; centers' 
 movements 'of 
 face 
 
 1 st - front. con<v. .Ascending parietal convr, 
 2* front.conv-. \ w r 
 
 "ure of Rolando 
 
 IMblor centers of fore-legs 
 
 d-obule'of the ascend par. Conv. 
 /Lotor centers Or kind-legs. 
 Tor cerlain movements, 
 of eyes 'and vision. 
 
 Y- 
 S'fnmt.cpmrn I 
 
 ' r rotation, j I 
 :ad &.neckx^ 
 
 Curvedfr 
 
 Asc.fronl/-coar. 
 
 Motor- centers for "hearing" 
 moveinentSfof 
 
 FIG. 2. External face of the brain of the magot monkey (Pithecus Innuus). 
 Broca and Gromier. 
 
 taken from the work of Gromier. It is a brain of the magot 
 (Pithecus innuus), a monkey of somewhat low type. I will 
 give a description of the external face of the hemisphere only, 
 the internal and inferior faces being of less importance to our 
 subject. 
 
 First, two long fissures are seen, the fissure of Rolando 
 and that of Sylvius. These fissures converge and constitute 
 the posterior border of the external face of the frontal lobe. 
 
 Further back is seen another fissure, the parieto-occipital. 
 In the monkey this 'fissure very clearly separates the occipital 
 lobe from the temporal and parietal lobes. This separation 
 is much less marked in the human brain on account of the 
 overlying convolutions (plis de passage) which more or less 
 conceal it. 
 
10 DISEASES OF THE BRAIN. 
 
 The parietal and sphenoidal lobes are less distinguishable 
 in the monkey, and to complete the outline it is necessary to 
 prolong the fissure of Sylvius with an imaginary line passing a 
 convolution called the gyrus angular is (pli courbe.) 
 
 The external surface of the cerebral hemisphere is divided 
 into four lobes, the frontal, parietal, sphenoidal, and occipital. 
 
 Each of these lobes is subdivided by fissures or sulci of 
 the second order into secondary lobes, called convolutions. 
 
 Frontal Lobes. TJie free central or curved frontal fissure 
 in the frontal lobe is the anterior border of a convolution 
 lying parallel with the fissures of Sylvius called the ascending 
 frontal convolution, and to give it more interest, I will ob- 
 serve that in its superior extremity Ferrier locates the motor 
 centres of the opposite upper limbs. 
 
 Fissures running at right angles with the curved frontal 
 fissure divide the remainder of the frontal lobe into three 
 convolutions. 1st In the posterior extremity of the first or 
 upper convolution Ferrier places the motor centre for the 
 movement of the head ; v 2d. Upon the same authority the 
 posterior part of the second or middle convolution is the 
 centre of facial movements ; 3d. In the third or lower convo- 
 lution is located, in the monkey, a motor centre for move- 
 ments of the lips and tongue ; to this part is ascribed in 
 man the faculty of articulate speech the third convolution, 
 or as the English call it, Brocas convolution. I do not wish 
 to be less French than are the English, and in adopting the 
 term I am happy to recognize the signal service which our 
 colleague has rendered to the cause of cerebral localization. 
 
 Parietal Lobe. The parietal lobe, so difficult of study in 
 man, is on the contrary very easy in the monkey. The 
 interparietal fissure divides it into two secondary lobes : 1st. 
 The superior parietal lobe, where Ferrier locates the centre 
 for movements of the lower limbs ; 2d. The inferior parietal 
 lobe ; 3d. A fissure, more marked in the higher monkeys, sepa- 
 rates the parietal lobes from the ascending parietal convolu- 
 tion. In a part of the ascending parietal convolution, and 
 extending to the superior extremity of the ascending frontal 
 convolution, is the motor centre of the upper limbs. 
 
LOCALIZATION IN CEREBRAL DISEASES. 
 
 II 
 
 Sphenoidal Lobe. The situation of the sphenoidal lobe is 
 easily understood. Upon the convex face of the hemisphere 
 it is bounded by the lower border of the hemisphere and by 
 the fissure of Sylvius. The parallel fissure, called thus 
 because it is parallel to the fissure of Sylvius, divides the lobe 
 into two parts. In the upper part is found the marginal con- 
 volution, and at the posterior end of the fissure, the gyrus 
 angularis, the removal of which Ferrier says produces tem- 
 porary blindness of the opposite eye. 
 
 Occipital Lobe. A transverse furrow separates this lobe 
 into two parts. For the present there is nothing special to 
 be said of it. 
 
 After this brief survey of the cerebral convolutions in the 
 monkey, the corresponding ones in man become more sim- 
 
 Sup. parifit'I J/Me, ** &*>**<>* /* , / *yy>. 
 / //**** 
 
 , Of/Rolando,, 
 
 -parietal 
 fissure^ *w 
 PM 
 
 s, 
 
 a 
 
 Fissure of Sylviu 
 
 ParaEd'ssure. 
 
 FIG. 3. Convex surface of a hemisphere of the human brain (parietal lobe partly 
 schematic.) 
 
 plified, as proved by the recapitulation which I will now 
 give, using for that purpose a plate from Foville's beautiful 
 work (Fig. 3). 
 
 You observe that the fissure of Sylvius and the fissure of 
 Rolando furnish the inferior and posterior borders of the 
 
12 DISEASES OF THE BRAIN. 
 
 frontal lobe, in which lobe you may notice the ascending 
 frontal (or anterior parietal) convolution and the first, second 
 and third frontal convolutions. (Fig. 3.) 
 
 The parieto-occipital fissure, on account of its overlying 
 folds (pits de passage), affords but a confused separation 
 between the occipital, parietal, and sphenoidal lobes. 
 
 Back of the fissure of Rolando, between that and the inter- 
 parietal fissure, is the ascending parietal convolution ; above 
 and back of the interparietal fissure you will find, successively, 
 the superior and inferior parietal lobules and the gyrus angu- 
 laris. 
 
 In the sphenoidal or temporal lobe, the brain, both of the 
 human and the monkey, has a fissure that extends to the 
 gyrus angularis ; this is the parallel fissure ; between it and 
 the fissure of Sylvius lies the first temporal convolution ; 
 below and posterior are the two other temporal convolutions. 
 
 The parietal lobe, the fissure of Sylvius and that of Rolando, 
 afford a sufficient number of starting-points to serve as guides 
 in autopsy. 
 
 III. Thus the surface of the brain is marked off into divi- 
 sions, the invariableness of which cannot be misunderstood. 
 Do these various fundamental convolutions represent distinct 
 functional centres ? A consideration of only the external 
 achitecture cannot resolve the question. 
 
 We will now resort to the microscope to ascertain whether 
 a comparative study of structure in the various regions of the 
 cortex will not furnish still more significant information upon 
 this subject. 
 
 Unaided vision has long since recognized differences of 
 structure in the gray substance, according to the encephalic 
 region examined. From this point of view let us examine, 
 for example, the lower portion of the occipital lobe. In those 
 parts of the lobe which surround the posterior cornua of the 
 lateral ventricles, the gray substance is not of that almost 
 uniform appearance which belongs to other regions of the 
 brain, as, for instance, to the anterior lobes. Vicq d'Azyr 
 observed that in those parts of the occipital lobes the gray 
 
LOCALIZATION IN CEREBRAL DISEASES. 13 
 
 substance of the convolutions was very clearly divided into 
 two secondary bands, separated by a white line which is still 
 called the band of Vicq cT Azyr. In this respect also the un- 
 assisted eye can distinguish between the gray substance of 
 the cornua Ammonis, the isle of Reil, and that of other 
 regions of the hemispheres. 
 
 To appreciate the value of these facts it is necessary to 
 enter more into detail. 
 
SECOND LECTURE. 
 
 STRUCTURE OF THE GRAY SUBSTANCE OF THE BRAIN. 
 
 Summary : General Structural Character of the Brain-Cortex. 1st ; 
 Ganglionic or Nerve Cells ; Pyramidal Cells. "Views Respecting the 
 Nerve-Cells of the Anterior Cornua of the Gray Substance of the 
 Spinal Cord (Motor-Cells); Size, Form, Body, Nucleus, Niicleolus, Pro- 
 toplasma, F ibrillic and Granules ; Nerve Network ; Prolongations 
 of Protoplasma ; Nerve-Prolongations. Comparison of the Motor 
 Nerve-Cells of the Spinal Cord with the Pyramidal Cells. Pyram- 
 idal Cells ; Size ; the Small Cells ; the Large or Giant Cells ; Composi- 
 tion of the Cells ; Shape, Body, Nucleus, Nucleolus ; Cellular Prolonga- 
 tions ; Pyramidal Prolongations; Prolongations which Recall those 
 of the Protoplasma ; Basal Prolongations. 3d and 3d ; Elements of 
 Globular Cells; Elongated Cells. 4th and 5th; Medullary Tubes; 
 Neuroglia or Amorphous Cerebral Substance. Relations between 
 the Elements ; Five-layer Type. The Importance of Examining the 
 Gray Substance of each Convolution. Two Divisions, Structurally, 
 of the Gray Substance. Labors of Betz. 
 
 GENTLEMEN : 
 
 I. The structure of the gray substance, in whatever region 
 of the hemispheres, presents certain general characteristics 
 which should be examined before approaching distinctive 
 characteristics. All parts of the cortex are composed of 
 essentially the same elements. Each one of the composing 
 elements may present important relative deviations from the 
 standard type, according to the region observed ; and in a 
 regional study of the gray substance great weight should be 
 given to the different proportion and manner in which these 
 elements are distributed in different parts. 
 
 After having examined these components individually, we 
 will investigate as to how they combine to form the gray 
 substance. Our description will commence with those ele- 
 ments which play the principal role, that is, those ganglionic 
 
THE GRAY SUBSTANCE OF THE BRAIN. 15 
 
 or nerve-cells which are the special characteristic elements 
 of this region ; they are usually called the pyramidal cells. 
 
 In order to fully appreciate the morphological properties 
 of these elements, perhaps it is best not to confine our atten- 
 tion to them exclusively. I have thought best to employ the 
 comparative method, reposing upon the common saying : 
 " Light is born from contrast" (" La Imniere nait du con- 
 trast e "). 
 
 I will first recite the principal traits of that nerve cellular 
 element which is at present best understood : I refer to the 
 nerve-cells of the anterior cormta of the gray siibstance of the 
 spinal cord, called the motor cells. The abridged description 
 which I will give of these nerve-cells will serve as a type. 
 In the comparisons that follow I shall point out more than 
 one difference, but I shall also make special mention of more 
 than one remarkable analogy. 
 
 The motor cells are cells without a distinct membrane, the 
 diameters of which are variable, though not deviating greatly 
 from 0.050 m. Gerlach, however, says that they may reach 
 to o.i 20 m. Their form is more or less globular, rarely 
 elongated. The bodies are composed of protoplasm which 
 appears granular when seen in the non-living state, but in the 
 serum, or after the action of osmic acid upon the fresh cell, 
 it appears to be composed of a transparent protoplasm in the 
 interior of which, as Shultz has demonstrated, exist numer- 
 ous fibrilla. These fibrillae by post-mortem alterations 
 change to granules. The cell contains a nucleus and a 
 brilliant nucleolus. I also generally observe in the proto- 
 plasm, even in its physiological condition, the presence of 
 brown pigmentary granules. 
 
 One of the most important peculiarities of these cells, how- 
 ever, is that they are armed with numerous prolongations, 
 which have a voluminous trunk as they leave the cells, and 
 which become smaller in proportion as they extend and 
 divide (dichotomously). The last of these ramifications are 
 extremely minute, and it is difficult to trace them for any 
 distance. 
 
 Gerlach, after the use of preparations of chloride of gold, 
 
16 DISEASES OF THE BRAIN. 
 
 asserts that these ramifications terminate in a sort of anas- 
 tomosing network which he called reseau nerveux. These 
 prolongations are composed, like the cell-bodies themselves, 
 of granular protoplasm and long parallel filaments, which 
 may be traced into the body of the cells. They are called 
 protoplasmic prolongations, in order to distinguish them from 
 another species of prolongation which I will now describe. 
 
 A German histologist, Deiters, some years ago discovered 
 an important fact which has since been verified by all anato- 
 mists. It is that the greater part, if not all, of the motor 
 cells possess, besides the prolongation which we have de- 
 scribed, a prolongation (one only for each cell) which charac- 
 teristically differs from the others. These prolongations bear 
 the name of nerve-prolongations, and the reason of that quali- 
 fication will be presently understood. It proceeds from the 
 body of the cell, or from one of its larger prolongations, in 
 the form of a very slender filament, but which, little by little, 
 becomes more voluminous. This prolongation does not 
 ramify, and it becomes less brightly colored by action of 
 carmine than do \h.t protoplasmic prolongations. 
 
 If followed a sufficient distance, it is found to be enveloped, 
 the same as an ordinary nerve, with a myeline cylinder, so 
 that it may be considered as a cylinder axis at its origin, and 
 at a certain distance as a complete nerve. The connection 
 of the nerve-cells with the tubes of the medullary substance, 
 by means of these prolongations (nerves), is then beyond 
 doubt. 
 
 Such are the principal characters of the spinal motor nerve- 
 cells ; and here seems the place to observe the characteristics 
 of the pyramidal cells of the gray cortex (Fig. 4). 
 
 These cells are quite variable in dimensions, the most of 
 them are relatively very small. The pyramidal cells, which 
 may be placed in this class, have at the base a mean diameter 
 of o.oio m. Those of the larger sort, less in number than 
 the preceding, generally occupy the lower portion of the 
 layer of pyramidal cells. Their diameter attains to 0.022 m. 
 (Koschewnikoff). 
 
 Finally there are giant pyramidal cells (Riesenzellen). 
 
THE GRAY SUBSTANCE OF THE BRAIN. 
 
 They have been carefully studied by Betz (of Kiew) and by 
 Mierzejewski. They are found in certain well-determined 
 regions of the gray cortex. The diameters of these gigantic 
 cells sometimes reach 0.040 
 m. to 0.050 m. , that is, they 
 equal the cells of the ante- 
 rior cornua of the spinal 
 cord. 
 
 However they may differ 
 in dimensions, the essential 
 structure of the pyramidal 
 cells appears always the 
 same. Therefore, for con- 
 venience' sake, we will 
 study the larger kind, or 
 the giant-cells. 
 
 To a certain point the 
 term pyramidal cells may 
 be used literally ; their form 
 resembles, indeed, a more 
 or less elongated pyramid. 
 The body of the cell re- 
 calls the description which 
 we have just given, and 
 Schultz records that he has 
 seen fibre-like structure in 
 it. The nucleus, according 
 to very many authors, is 
 angular, and reproduces in 
 a certain degree the gen- 
 eral form of the cell. The 
 nucleolus itself presents no- 
 thing special. 
 
 The cellular prolongations offer peculiarities worthy of in- 
 terest. One of them may be called pyramidal prolongations, 
 for it is, as it were, the body of the cell progressively nar- 
 rowed. As they extend they give off lateral branches, and 
 at their extremities they often divide in form of a fork, and 
 2 
 
 FIG. 4. Pyramidal prolongation. 
 
1 8 DISEASES OF THE BRAIN. 
 
 this extremity is always directed towards the surface of the 
 convolution. It follows that the cell is situated so that its 
 base is parallel to the interior or medullary border of the 
 zone of the gray cortex. 
 
 Other prolongations of the same category extend some- 
 times from the angles, sometimes from the base, and they 
 ramify in such manner as to recall the protoplasmic prolonga- 
 tions of the spinal motor cells. Do these prolongations ter- 
 minate in a nerve network in the gray cortex, the same as 
 Gerlach says occurs with the spinal cells ? Some authors say 
 they do. 
 
 There certainly exist for the larger pyramidal cells, for the 
 giant-cells, and perhaps for the small cells, cylindrical prolon- 
 gations quite analogous to those of the spinal motor cells. 
 In both, the origin is a slender filament which soon becomes 
 somewhat larger. Upon successful dissections it is possible, 
 at a certain distance from the cell, to discover that the pro- 
 longations are covered with a cylinder of myeline. Koschew- 
 nikoff 1 placed this fact beyond doubt by examination of 
 cells from the anterior lobes of the brain of one who died 
 from encephalitis ; and since the publication of his work the 
 reality of his description has often been demonstrated by 
 others. These basilar prolongations, to use Meynert's expres- 
 sion, are always turned towards the medullary substance of 
 the convolutions. 
 
 That which we have adduced makes it impossible to misun- 
 derstand the analogies associating the pyramidal cells of the 
 gray cortex at least the large cells and the giant-cells with 
 the motor cells of the anterior cornua of the spinal cord ; and 
 these analogies (already described by Luys : J. Luys, Recherche s 
 sur le systeme nervetix, etc., p. 162 et suiv., Paris, 1865) we 
 must consider later. 
 
 1 A. Koschewnikoff. Axencylinderforsatz der Nervenzellen im kleinen Him des 
 Kalbes. In Schultze's Archiv, p. 332, 1869. Axencylinderforsatz der Nervenzel- 
 len aus der Grosshirnrinde. Idem, 1869, p. 375. Betz, Centralblatt. 1874, p. 579 ; 
 Mierzejewski, Etudes sur les lesions cerebrales dans la paralysie genrale, in 
 Archives de physiologic, p. 194, 1875. J. Batty Tuke, Morisonian Lectures, in 
 Edinb. Med. Journal, p. 394, May, 1874. 
 
THE GRAY SUBSTANCE OF THE BRAIN. IQ 
 
 The pyramidal cells are not the only elements found in the 
 gray substance. There are also small globular cells (rarely 
 pyramidal), measuring from 0.008 m. to o.oio m. (Meynert), 1 
 sometimes furnished with small prolongations ; they are 
 generally sparse, though sometimes, or at some points, they 
 form a tolerably thick layer. Various writers have regarded 
 them as incompletely developed nerve-elements ; others again 
 have denied them this character, and compare them to the 
 elements which constitute the granular layer of the retina. 
 
 Meynert ranks also among the nerve-elements of the corti- 
 cal zones a kind of elongated, generally fusiform, ramified 
 cell, and which at certain points constitutes a fifth layer. 
 These cells generally have their grand axis directed parallel 
 with the fibres which connect the convolutions (the system 
 of association}, medullary fibres that run from one convolution 
 to another (fibrae arcuatse) ; the last-named cells seem to 
 make a part of that system. 
 
 These, then, are the cellular nerve-elements, so reputed, 
 which enter into the structure of the gray substance. Besides 
 these, there are other elements which we ought to mention : 
 the medullary tubes and the amorphous cerebral substance 
 (neuroglia). To these last, which penetrate the gray substance 
 as fasciculi, we will return later. As for the neuroglia, still 
 known under the name of formation ependymaire (Roki- 
 tansky), that serves as an amorphous uniting substance. I 
 will not enter into the detail of the peculiarities of structure 
 relative to the neuroglia of the gray substance. I will only 
 remark that latterly it has been considered by various authors 
 as composed of a peculiar kind of conjunctive cells, the bodies 
 of which contain very little protoplasm, and are furnished 
 with non-ramified prolongations (cellules araignees de Boll et 
 Golgi). These prolongations, entangled and cemented by an 
 interposed gelatinous substance, would be considered as com- 
 posing the entire mass of neuroglia. We must examine that 
 interpretation. Without denying the normal existence, in 
 certain regions, of ramifying cells (cellules de Deiters), I will 
 
 1 Meynert. Strieker's Handb., t. II., et traduct. anglaise,|t. II., p. 381 et suiv. 
 
2O DISEASES OF THE BRAIN. 
 
 remark that the gray substance in that respect is very likely 
 fashioned upon the same model as is the white. In other 
 words, the neuroglia resembles the type of ordinary conjunc- 
 tive tissue, conjunctive fasciculi, and flat cells (Ranvier) ; only 
 in the neuroglia the fibrous filaments would be freer than else- 
 where. For the present, I omit the study of the vessels ; they 
 will shortly receive our special attention. 
 
 This suffices, I think, concerning the individual history of 
 the various elements which compose the gray substance. 
 We should now examine the method in which these elements 
 are arranged, in order to see what may be the difference in 
 arrangement, as well also as in respect to the constitution of 
 the elements themselves, in each of the various regions which 
 are divided off by the main fissures on the surface of the brain. 
 
 There is a certain arrangement which may be considered 
 as representing the most common type, and it is also the 
 most widely extended ; it is the one that in thin slices may 
 be distinguished with the microscope, and which presents 
 five successive layers. It is met with nearly everywhere in 
 the anterior lobes. The elements are separated as follows : 
 
 i. The first layer, the one nearest the meninges, is com- 
 posed almost exclusively of conjunctive substance. There 
 the nerve-elements are very scarce ; Kolliker and Arndt, 1 
 however, describe a layer near the surface, under the pia 
 mater, of very delicate parallel nerve-tubes. The nerve-cells 
 in this locality are very sparse. To the naked eye that layer 
 has the appearance of a little white zone. The absence of 
 color seems due to the poverty of nerve-elements and to the 
 small number of capillary vessels contained in the layer. 
 Indeed the arterioles penetrating the cortex do not furnish 
 numerous capillaries except to the lower layer. That pecu- 
 liarity of structure is very well indicated in a plate by Henle, 2 
 and in a cut in the memoire of Duret. 3 
 
 1 R. Arndt. Studien iiber die Architektonick der Grosshirnrinde des Menschen, 
 in Arch, fur mikroskop. Anatomic, 3d Bd. 1867, p. 441, Taf. xxiii., Fig. i, a, et 
 Fig. 2. 
 
 2 J. Henle. Handb. der Nervenlehre, p. 274, Fig. 201, Braunschweig, 1871. 
 
 3 Archives de Physiologic, T. vi., pi. 6, Figs. 2 et 3. 
 
THE GRAY SUBSTANCE OF THE BRAIN. 
 
 21 
 
 2. The second layer (Fig. 
 5) is marked by an agglom- 
 eration of pyramidal nerve- 
 cells of the small species, 
 numerous and very close 
 together, which give it a 
 decided gray color. 
 
 3. The third layer (Fig. 
 5) is chiefly composed of 
 pyramidal cells, some of 
 the medium size and some 
 voluminous. The latter, 
 more separated from each 
 other than the first, are 
 generally situated at the 
 lower part of the layer, and 
 penetrate even into the 
 next (fourth) layer. Be- 
 sides the cells there are to 
 be found in the third layer 
 fasciculi of medullary fibres 
 which dip perpendicularly 
 to the surface of the cor- 
 tex, forming as it were col- 
 umns between the groups 
 of pyramidal cells. This ar- 
 rangement has been faith- 
 fully represented by Luys l 
 and by Henle. 2 It is in the 
 lower portions of the third 
 layer that in some regions 
 the giant-cells exist. It 
 would seem as though the 
 rarity of cells and the pres- ~ 
 ence of medullary fibres 
 ought to give this layer a 
 
 white appearance ; it really FIG. 5. Five-layer type of cerebral cor- 
 i 11-1 i tex. (Brain of mamrr 
 
 has a yellowish COlor, prob- p rom Strieker's Hand-book. 
 
 mammalia.) Meynert. 
 T. II., p. 704. 
 
 1 Atlas, etc., pi. xx., Fig. 4. 
 
 2 Loc. cit., Fig. 198, p. 271. 
 
22 DISEASES OF THE BRAIN. 
 
 ably from the presence of pigment and the abundance of 
 capillary vessels. 
 
 4. Then comes the fourth layer (Fig. 5), where are seen the 
 globular cells with ill-determined characters, and the fifth 
 layer, where are found the fusiform cells of which we have 
 just spoken. 
 
 These summary investigations have enabled us to appre- 
 ciate the interest which might result from an examination of 
 the structure of the gray cortical substance, made convolu- 
 tion by convolution. It has long been known that the differ- 
 ent regions of the gray cortex differ notably from each other 
 in point of structure. But the most recent and fertile study 
 in this direction is by Betz, the results of which have been pub- 
 lished in the Centralblatt of the past year. 1 Betz proposes 
 examining the modifications of texture of the gray substance, 
 convolution by convolution. In this respect he claims that 
 on the surfaces of the hemispheres there are two fundamental 
 regions which are nearly divided by the fissure of Rolando. 
 
 Anterior to that furrow the gray cortex is characterized by 
 a predominance of large pyramidal cells over the globular 
 cells. The orbital region is included in this division. 
 
 Back of the furrow this region embraces all the sphenoidal 
 and occipital lobes and the median portion, to the anterior 
 border of the quadrilateral lobule. There the granular cells 
 preponderate, and the large ones are relatively rare. 
 
 Besides this there is a special department in each of these 
 regions which deserves attention. We will deal first with that 
 of the posterior region. 
 
 ist. Here, the well-developed nerve-elements are the toler- 
 ably large cells. According to Meynert they were the 
 largest found in the cortex of the hemispheres before the dis- 
 covery of the giant-cells. They are sometimes the 0.030 m. 
 in diameter. The protoplasmic prolongations are not nu- 
 merous ; the basilar prolongations are directed horizontally, 
 and sometimes constitute communications between the cells. 
 
 1 P. Betz, of Kiew. Anatomischer Nachweis Zweier Gehirncentra. In Cen- 
 tralblatt, 1874, Nos. 37 et 38. 
 
THE GRAY SUBSTANCE OF THE BRAIN. 23 
 
 The territory where that character is observed includes (a) 
 the cuneus ; (b) the posterior half of the lingual and fusiform 
 lobules ; (c) all the occipital lobe ; (d) the first two sphenoi- 
 dal convolutions and the transition convolution (pit de pas- 
 sage]. According to Betz, this region is devoted to the 
 functions of sensibility. From other reasons of an anatomi- 
 cal order, to which we will revert, the posterior parts of the 
 brain have for a long time past been spoken of as the seat of 
 the sensorium. 
 
 2d. The anterior lobe deserves particular notice, and may 
 be called (you will see why) the department of the giant 
 pyramidal cells, or the motor cells par excellence. This de- 
 partment embraces the entire ascending frontal convolution, 
 the superior extremity of the ascending parietal convolution, 
 together with a part which we will soon study under the 
 name of paracentral lobule, and which is situated upon the 
 internal face of the hemisphere at the extremity of the as- 
 cending convolutions. It is here that exist almost exclusively 
 the giant-cells. Their distribution is not uniform, for they 
 are more numerous than elsewhere at the superior extremity 
 of the two middle convolutions, and above ttll in the para- 
 central lobule. They are located in groups or islands. 
 They are to be found in certain points, which will be indi- 
 cated, in all species of monkeys, the inferior as well as the 
 chimpanzee. Indeed Betz has observed in the dog the 
 same kind of cells at those points designated by Fritsch and 
 Hitzig as motor centres otherwise spoken of as the parts 
 neighboring the sulcus cruciatus. Interest is added by the 
 fact that in the dog the giant pyramidal cells exist nowhere 
 else but in the regions called psycho-motor. It doubtless has 
 not escaped your notice that in the monkey the distribution 
 of the large nerve-cells very closely corresponds to those con- 
 volutions where experiments, in the hands of Ferrier, have 
 demonstrated the existence of motor points, namely, in the 
 central convolutions. This is an interesting result furnished 
 by histological study, and which, combined with experimental 
 or anatomico-pathological results, cannot fail to throw some 
 light upon the development of cerebral localizations. 
 
THIRD LECTURE. 
 
 CONSIDERATIONS UPON THE NORMAL STRUCTURE OF 
 THE GRAY SUBSTANCE OF THE CONVOLUTIONS. 
 
 (CONTINUATION.) 
 
 Summary : Description of a Section of the Gray Matter of the Cere- 
 helium. Type of the Five-Layer Stratifications of Cellular Nerve- 
 Elements. Regions where this Type of Stratification Exists. De- 
 partment of Pyramidal or Giant-Cells. Relations between the Cells 
 and the Psycho-motor Centres. Description of the Internal Face of 
 the Cerebral Hemispheres. Paracentral Lobule. Ascending Convo- 
 lutions. Clinical and Experimental Facts Relative to the Develop- 
 ment of the Pyramidal Giant-Cells. Structure of the Gray Matter 
 in the Posterior Regions of the Encephalon. 
 
 GENTLEMEN : 
 
 Before proceeding further towards the purpose of our 
 subject the theory of localization in cerebral maladies 
 I ought to complete the matter broached in the last lecture, 
 relative to the differences in the normal structure of the gray 
 matter, as found in the various convolutions of the cerebral 
 hemispheres. 
 
 A. We will first examine the common type, or the one most 
 generally and best understood. With Meynert, one may call 
 it the five- layer type of cellular nerve-elements so reputed. 
 
 I will briefly recall the characteristic traits of that type. 
 To assist in this let us again glance at Fig. 5, a section of the 
 third frontal convolution at the base of a fissure. 
 
 As a contrast, we will run over the description of a section 
 of the gray substance of the cerebellum ; this description, like 
 the preceding one, is borrowed from Meynert. In the 
 gray substance of the cerebellum there are, in successive 
 order : 1st. A thick layer, poor in cellular elements, and 
 which receives the protoplasmic prolongations from the nerve- 
 
NORMAL STRUCTURE OF THE CONVOLUTIONS. 2$ 
 
 cells of the subjacent layer. 2d. Below this, a layer where 
 are found, according to Meynert, fusiform cells and medul- 
 lary fibres running parallel to the line of limit. 3d. Still 
 lower, the cells of Purkinje, which occupy the superior por- 
 tion of a very granular layer ; below all, the medullary sub- 
 stance. 1 
 
 If you now examine the figure representing the five layers 
 of gray substance of the brain proper (cerebrum), you will 
 see that the gray substance is not fashioned in all parts of 
 the encephalon upon the same model. I shall shortly show 
 you the very well-defined though not so strongly marked dif- 
 ferences that are apparent according to the different regions 
 examined in the cerebrum ; but first I must return to the five- 
 layer type. 
 
 B. The arrangement thus designated exists in all the brain 
 anterior to the fissure of Rolando, as well also as a little back 
 of it, in a portion of the parietal lobes which is indistinctly 
 separated from the border of the occipital lobe. We will 
 presently see that this type is notably modified in the pos- 
 terior part of the encephalon, including, 1st. All the sphe- 
 noidal lobe ; 2d. The occipital lobe ; and 3d. The gray matter 
 of that portion of the internal face which is circumscribed by 
 the posterior extremity of the occipital lobe and by a furrow 
 which is the posterior limit of a distinct region, which we will 
 shortly describe under the name of the quadrilateral lobule. 
 
 (a.) For greater clearness it is necessary to revisit a point 
 already surveyed ; namely, that in those regions of the hemi- 
 spheres occupied exclusively by the five-layer type, there 
 exists a department of itself, where the gray structure is dis- 
 tinguished by an interesting peculiarity ; which is, the invaria- 
 ble presence in those parts of comparatively enormous pyram- 
 idal cells, and which, on account of their size, are called giant- 
 cells. While these cells retain the pyramidal form common 
 to the cellular nerve-elements of these regions, they differ 
 not only in dimensions, but also by the distinctness of their 
 nerve-prolongations and by the development of their proto- 
 
 1 Voir aussi Henle, Nervenlehre, etc., Figs. 162, 163 A, 163 B. 
 
26 
 
 DISEASES OF THE BRAIN. 
 
 plasmic prolongations. This last trait permits their compari- 
 son with the motor nerve-cells of the anterior cornua of the 
 spinal cord. 
 
 The regions of this important peculiarity are the central 
 regions of the external surface of the hemisphere, to wit : 
 the ascending frontal convolution, the ascending parietal con- 
 volution, especially at their superior parts, and finally in a 
 little lobule situated upon the internal face of the hemisphere, 
 until recently unnamed, and which Betz has proposed to call 
 \hzparacentral lobule, (Fig. 6.) 
 
 Sujx extremity of fisS. of Rolando, 
 Iransverse furrow of paracentral lobiLlc.'' 
 
 Tril. face' of fir-si 
 frontal convolution. 
 
 FIG. 6. 
 
 nature.") * 
 
 ge. or. Cuneiform lobule.-' 
 
 j Occipital lobe. * 
 
 AnrJLexLT>ortmofCrus Ceretri 'Cavity of .lateral veritncle- 
 Cioioid plexus. 
 
 Internal surface of right hemisphere of a human brain. {Drawn from 
 
 I would remind you that the existence of the giant-cells in 
 the gray matter, and their localization in the regions above 
 indicated, were discovered by Betz and Mierzejewski. The 
 results obtained by these authors have recently been con- 
 
 1 Respecting the topography of the median face of the cerebrum, consult pi. 
 viii. of Foville's Atlas, and Fig. 4 of Ecker's work. 
 
NORMAL STRUCTURE OF THE CONVOLUTIONS. 2/ 
 
 firmed by J. Batty Tuke in his lectures at Edinburgh. 1 I 
 have myself also verified the same. 
 
 I again remind you that the regions remarkable for this 
 peculiarity of structure are precisely those where, in the 
 monkey, according to Ferrier, 2 the psycho-motor centres of 
 the limbs are located. Is not that a coincidence worthy of 
 your attention ? Let us recall the fact also that, in the dog, 
 those parts reputed, through the experiments of Ferrier and 
 by the previous ones of Hitzig, as excito-motor, are said by 
 Betz to be distinguished by the presence of giant pyramidal 
 cells cells which in these animals are to be found in no other 
 part of the gray matter. I think my persistence justified by 
 the necessity of fixing in your minds as exactly as possible all 
 these details. 
 
 (<.) These facts give a very special interest to those regions 
 of the hemispheres which possess this anatomical peculiarity. 
 I therefore feel that a thorough topographic knowledge of 
 those regions is of the utmost use in order to be able to indi- 
 cate them with precision in the records of autopsies, and con- 
 sequently I will enter this subject more fully. In so doing 
 we shall of course have occasion to describe the configuration 
 of the middle faces of the hemispheres, a region which up 
 to the present time, in my opinion, has remained too little 
 known. 
 
 The arrangement of the ascending convolutions, their ori- 
 gin at the superior border of the hemispheres, are now so 
 familiar to us that our attention can be turned to the arrange- 
 ment of the internal or median faces of the hemispheres. In 
 that section (Fig. 6) which divides the corpus callosum antero- 
 posteriorly you first see at the centre the divided surface 
 of the grand commissure ; below, the septum lucidum, the in- 
 ternal face of the thalamus opticus, then the cut surfaces of the 
 crura cerebri. 
 
 Better to obtain our points of compass, we will start from a 
 
 1 Edinburgh Med. Jour., Nov., 1874, p. 394. 
 
 2 West Riding Asylum, t. IV., pp. 49 and 50, Proceedings of the Royal Society, 
 No. 151, 1874. British Medical Journal, Dec. 19, 1874. 
 
28 DISEASES OF THE BRAIN. 
 
 familiar landmark upon the external face of the brain, that is, 
 the fissure of Rolando, and follow it to its extreme internal 
 end. This furrow sometimes stops a little short of the inter- 
 hemispheric fissure ; at other times it extends quite to it, 
 making a sort of notch on its superior border. 
 
 The paracentral lobule is located immediately below that 
 point. It is bounded as follows : posteriorly, by an oblique 
 fissure, which is the posterior prolongation of the calloso-mar- 
 ginal (that fissure extended constitutes the posterior border 
 of the ascending parietal convolution) ; below, by that horizon- 
 tal portion of the calloso-marginal fissure which separates it 
 from the convolution of the corpus callosum (called gyrus 
 fornicatns) ; anteriorly, by a fissure generally shallow, but 
 which sometimes continues upon the internal face of the hemi- 
 spheres and which anteriorly marks the internal part of the 
 ascending frontal convolution and bounds the anterior face of 
 the paracentral lobule. 
 
 Thus we have a small quadrilateral lobule whose greatest 
 diameter is antero-posterior. Generally a shallow furrow, 
 midway between the upper and lower borders, runs the entire 
 length of the lobule. By reason of its structure, as much as 
 from its position, it may be said that the paracentral lobule 
 seems to represent upon the median face of the hemisphere 
 the inverse surfaces, the internal extremities of the two ascend- 
 ing convolutions. 
 
 This point fixed, it is not difficult to give the remaining 
 topography of the internal face of the hemispheres. 1st. 
 Anterior to the paracentral lobule is seen the median surface 
 of the first frontal convolution. 2d. Below, and separated 
 from the preceding by the calloso-marginal furrow, is the 
 convolution of the corpus callosum (gyrus fornicatus}. 3d. 
 The last-named convolution is continued posteriorly, forming a 
 lobule quite circumscribed, and which is called the quadrilat- 
 eral lobule (avant coin, Vorzwickel, prcecuneus). This lobule 
 we may consider as the internal or median face of the su- 
 perior parietal lobule. Behind this the temporo-occipital fis- 
 sure (very marked at this point, because it is not interrupted, 
 as upon its external face, by overlying convolutions) separates 
 
NORMAL STRUCTURE OF THE CONVOLUTIONS. 29 
 
 very clearly the quadrilateral lobule from the occipital lobe. 
 4th. Immediately behind the quadrilateral lobule in the 
 region of the occipital lobe, there is a triangular lobule, the 
 point of which is inferio-anterior, the base posterio-superior, 
 and which is bounded posteriorly by a deep fissure, theftssura 
 calcarina ; that little lobule is called the cuneus (com, 
 zwickel}. 5th. Below that triangle you observe the lack of 
 demarcation already noticed upon the external surface be- 
 tween the occipito-sphenoidal lobes. In this region should 
 be specially observed two convolutions running antero-pos- 
 teriorly. They are : (a) the lateral occipito-sphenoidal lobule 
 (lobulus fusiformis) ; (b) the median occipito-sphenoidal 
 lobule (lobulus lingualis). 6th. Still in front, and fully within 
 the sphenoidal lobe, is the gyrus hippocampi, the hook 
 (crochet) which constitutes part of the horn of Ammon (cornu 
 Ammonis). 
 
 As we proceed we shall most certainly have occasion to 
 use the topographical knowledge which we, are obtaining, and 
 I hasten to complete the description, which in some respects 
 is a digression. 
 
 C. I therefore return to the paracentral lobule and to the 
 ascending convolutions. These have already a history in 
 experimental pathology, and further on it will be shown that 
 they have also a history in human pathology. I am not 
 aware whether with the monkey, at least with the higher 
 grade of monkey, the paracentral lobule (which exists as with 
 man) has ever been the object of physiological investigations. 
 
 (a.) I may here cite a case, unique of its kind to be sure, 
 but which nevertheless will for the future lend an interest 
 to this lobule as connected with human pathology. This 
 instance, of which I give an outline, has been recorded by an 
 attentive observer, Sander. 1 
 
 A child who died at the age of fifteen had been attacked in 
 the third year of its age with infantile spinal paralysis. The 
 malady had included and more or less atrophied all the limbs, 
 and especially those of the left side. Autopsy revealed in 
 
 1 Centralblatt, 1875. 
 
30 DISEASES OF THE BRAIN. 
 
 the spinal cord all the lesions described by the French authors. 
 A minute examination of the brain led to the discovery that 
 the two ascending convolutions upon the external face were 
 very much shorter than normal. They left the island of Reil 
 somewhat uncovered, besides which they were destitute of 
 folds. The paracentral lobule was entirely rudimentary, in 
 this respect markedly in contrast with all the other convolu- 
 tions, which were perfectly developed. Lastly, the lesions 
 were most pronounced in the right hemisphere, which is in 
 keeping with the circumstance that the spinal lesions were 
 most marked upon the left side. 
 
 The author expresses the opinion that in this case the limbs 
 having, at an early age, suffered complete paralysis, resulting 
 from a profound spinal lesion, the psycho-motor centres, 
 struck with inertia at a time when they were in process of 
 evolution, had in consequence been arrested in development. 
 The interpretation seems worthy of consideration. It is much 
 to be regretted that the condition of the nerve-cells in the 
 psycho-motor centres was not ascertained. 
 
 A case observed by Luys to a certain extent resembles the 
 foregoing. In a subject where amputation had been made, 
 some years previous to autopsy, my colleague at la Salpe- 
 triere noted an atrophy of the cerebral convolution on the 
 side opposite to the amputation. Unfortunately the exact seat 
 of the atrophy was not (to my knowledge, at least) given. 
 
 (#.) I am thus led to introduce another fact concerning that 
 part of the brain with which we are occupied. According to 
 the researches of Betz, the giant pyramidal cells exist but in 
 small number with very young infants ; it is only later that 
 their number increases, and that increase is effected, accord- 
 ing to all appearances, under the influence of functional 
 exercise. 
 
 This fact is worthy of being joined, on the one hand, with 
 that of Sander's, and on the other hand to an observation of 
 an experimental order recently recorded by Soltmann. 1 That 
 author (and I believe that Professor Rouget, of Montpellier, 
 
 1 Reizbarkeit der Grosshirnrinde, in Centralblatt, 1875, No. 14. 
 
NORMAL STRUCTURE OF THE CONVOLUTIONS. 31 
 
 has recorded something similar) has observed that with newly 
 born dogs the excitation of regions corresponding to the psy- 
 cho-motor points produces no muscular movement in the 
 corresponding limbs, whereas, some time after birth, towards 
 the ninth or eleventh days, these points become excitable. 
 
 These observations, though yet few, should nevertheless 
 be taken into account, and they would seem to indicate that 
 the psycho-motor centres are not pre-established, if one can 
 so speak, so much anatomically as they are physiologically. 
 They are developed by age, doubtless through functional 
 exercise. 
 
 In support of this view I offer a remark with which I will 
 terminate the special subject that has detained us. The 
 regions of the large cells belong to the five-layer type, and 
 these regions have no definite anatomical characteristic except 
 the presence of giant-cells. Now these giant-cells, morpho- 
 logically, do not differ essentially from the large pyramidal 
 cells, which also, according to the researches of Koschewnikoff, 
 possess, like them, the nerve-prolongations in addition to the 
 protoplasmic prolongations, attributed to motor cells. 
 
 It seems natural to inquire if these cells, and even those of 
 the smaller species, which are their miniature representatives, 
 would not be capable, under certain conditions under the 
 influence, for example, of abnormal functional excitement of 
 acquiring development, and in that way giving birth to sup- 
 plementary motor centres destined to replace primitive cen- 
 tres that by some lesion may have been destroyed. Thus, 
 for example, might be explained how voluntary movements 
 can be restored in a part, notwithstanding the destruction of 
 a motor centre a phenomenon, an example of which is fur- 
 nished in the frequent recovery from aphasia, in despite of 
 the persistence of the lesion of the third frontal convolution. 
 
 D. To complete the examination of the cerebral cortex, I 
 have but to add some little information upon its peculiarities 
 in the posterior region of the brain. 
 
 These peculiarities belong to the entire occipital lobe, the 
 sphenoidal lobe, and the posterior and median parts of the 
 hemisphere to the posterior border of the quadrilateral lobule. 
 
32 DISEASES OF THE BRAIN. 
 
 The general character of the gray substance in those regions 
 is that the pyramidal nerve-cells, as a rule, are very scarce 
 and small, while the granular, on the contrary, are notably 
 predominant. It is not that there are no large nerve-cells, 
 but they are comparatively rare solitary ', to employ the ex- 
 pression of Meynert. Betz adds that they have no nerve- 
 prolongations, and that even the protoplasmic prolongations 
 are scarcely developed. 
 
 The portion of the brain where this peculiarity is to be 
 observed corresponds, according to many authors, to the sen- 
 sorium commune. If this interpretation be correct, it would 
 follow that the cells of which we are about to speak are cells 
 of sensation. This hypothesis rests upon still other anatom- 
 ical considerations, and upon pathological evidence of which 
 I will hereafter give more detail. 
 
FOURTH LECTURE. 
 
 PARALLEL BETWEEN SPINAL AND CEREBRAL LESIONS. 
 
 Summary : The Indispensable Conditions for the Study of Cerebral 
 Localization in Diseases in Man. Necessity of Good Clinical Observa- 
 tions and Regular Autopsy. Natural History of Encephalic Lesions. 
 Parallel between the Grand Compartments of the Cerebro-gpinal 
 Axis. Systemization of Lesions in the Spinal Cord. Spinal Localiza- 
 tions. The Brain is placed under a Pathological Regime Differing 
 from other Parts of the Nerve-Axis ; Rarity of Localizations. Differ- 
 ence of Lesions. Frequency of Vascular Lesions in Maladies of the 
 Brain. Necessity of the Study of Vascular Distribution. Outline of 
 the Cerebral Arteries. 
 
 GENTLEMEN : 
 
 From the preceding lectures you comprehend that, unpre- 
 pared by a precise knowledge of normal anatomy, it would be 
 useless to undertake this subject. 
 
 The subordination of pathological to normal anatomy is 
 most especially obvious in all questions related to cerebral 
 pathology. This will directly be rendered still more evident. 
 
 I. To-day we will commence by recounting the indispensa- 
 ble conditions for solving the problems connected with local- 
 ization in cerebral diseases, as exhibited in man. 
 
 The following are the fundamental ones : 1st. A good clin- 
 ical observation made with the most complete possible knowl- 
 edge of existing facts in experimental physiology. 2d. A 
 regular, anatomically precise autopsy. 
 
 Our preceding topographical studies make an important 
 step, for they will better enable us to determine the locations, 
 extent, and configuration of lesions revealed by autopsy. 
 
 For the special object which we have in view, however, 
 even the most minute and exact anatomical observations can- 
 3 
 
34 DISEASES OF THE BRATN. 
 
 not always be utili/.eil. IIiMv as elsewhere, it is necessary 
 that observation should teach us how to select from things 
 seen, and in this process more than one difficulty must be 
 overcome. 
 
 To make you familiar with the situation it is best first to 
 survey the natural history of encephalic lesions. 
 
 \ st. What are the alterations capable of affecting the en- 
 cephalon, or especially the brain? We are now, of course, 
 dealing only with the most usual forms of cerebral disease 
 with partial or circumscribed lesions as they are called ; such 
 only can be profitably considered in this connection. 
 
 2d. In the second place, wli.it are the general anatomical 
 conditions which preside either at the development, or dur- 
 ing the process of reparation of such lesions ? For there is 
 no chance work, even in the encephalon. 
 
 To accomplish our end I propose once more to employ the 
 comparative method, that lever so powerful in natural sci- 
 ences. I will make, pathologico-anatomically, a comparison 
 between the grand cerebro-spinal compartments (or if you 
 choose Piorry's nomenclature, nem % -a.\'is)\ that is : 1st, the 
 spinal cord ; 2d, the rac Indian bulb ; 3d, the brain proper. 
 
 A. It may be said that the pathological physiology of the 
 spinal cord is distinguished by the extensive existence in it 
 of those lesions called systemic. By this expression, bor- 
 rowed from Vulpian, are meant those lesions which are sys- 
 temically (the term is perfectly appropriate) circumscribed, 
 and which do not overstep the limits of certain clearly deter- 
 mined regions in that complex organ. I beg to refer you to 
 figure No. 21, which will recall our past lectures. 
 
 You remember that there are lesions limited to the anterior 
 cornua of the gray substance (Fig. 7). They are, in acute 
 form, infantile paralysis ; in chronic form, the various kinds 
 of progressive locomotor ataxia. There are other lesions 
 limited to the lateral fasciculi and which are distinguished by 
 symptoms of numbness (paresie) with a tendency to contrac- 
 tions. You know that the fibres of Goll may alone be sub- 
 ject to lesions ; and that the regions of the little external bands 
 (Fig. 7) (posterior columns) in the area of the lateral fasciculi 
 
SPINAL AND CEREKRAL LESIONS. 
 
 35 
 
 is the only anatomical substratum necessary for symptoms 
 of spiiuil tabes. 
 
 It is thus that pathological anatomy, guided in its first steps 
 by experiment with animals, and aidi-d also by clinical ex- 
 perience, has become able to separate, in man, the complex 
 organ called the spinal cord, into a certain number of com- 
 partments, departments, and secondary organs. 
 
 Posf.Cornuj 
 
 \Post;. Cornxu 
 
 /fibers of Goll. 
 FIG. 7. Transverse section of spinal cord. 
 
 To each systemic lesion of these various regions belong 
 groups of symptoms or syndromes which clinically serve to 
 individualize them, and which have also given place, in path- 
 ological descriptions of the spinal cord, to a certain number 
 of elementary affections. Analysis, founded upon a knowl- 
 edge of the elementary affections, is a great help in unveiling 
 mixed or complex forms. 
 
 The study of these systemic lesions has doubtless contrib- 
 uted greatly to rescue spinal localization from its past chaos. 
 
 B. Systemic lesions are found extended to the rachidian 
 bulb, the protuberance, and the crura cerebri. I will cite for 
 examples the secondary degenerations of the cord consecutive 
 to lesions of the brain, primitive and symmetrical sclerosis of 
 
36 DISEASES OF THE BRAIN. 
 
 the lateral column, bulbous paralysis from exclusive lesion 
 of the ganglia at the origin of the nerves, etc. But above 
 that point this mode of pathological alteration does not ap- 
 pear to exist, and it may be said that to the present systemic 
 lesions in the brain are unknown. 
 
 No one really knows of systemic lesions limited to the 
 thalami optici, to the different ganglia of the corpora striata, 
 or to the various portions of the cortex. It does not follow, 
 however, that strict research cannot determine anatomical 
 localizations in the encephalon, but they are at present rela- 
 tively rare, and seemingly accidental. 
 
 What is the real reason of this singular fact ? It is that the 
 encephalon is placed under a pathological regime, so to speak, 
 differing from that controlling other portions of the nerve- 
 axis. In fact, speaking in a general way, in the encephalon, 
 and especially in the brain, the vascular system (arteries, 
 veins, and capillaries) commands the situation. 
 
 I will call attention to the importance of vascular ruptures 
 and ensuing hemorrhage in the intra-encephalic centres ; 
 the predominant role of vascular obliterations by thromboses 
 and emboli, the effect of which is extravasation followed by 
 partial softening of the brain. 
 
 I will enumerate the most common anatomical causes of 
 organic disease in the encephalon. 
 
 C. If we now return to the spinal cord and bulb, we will 
 observe a remarkable contrast to the encephalon. Hemor- 
 rhage by vascular rupture, whether resulting from the altera- 
 tion well known under the name of miliary aneurism, from 
 softening consecutive to arterial narrowing, or from throm- 
 bosis or embolism, is something which in the spinal cord is 
 almost unknown. 
 
 The bulb constitutes, as it were, the transition between the 
 spinal cord and the encephalon, for in the bulb is seen, on 
 the one hand, systemic lesions which recall those seen in the 
 cord, and on the other hand, a certain number of hemor- 
 rhages and softenings are found resulting from vascular 
 lesions. 
 
 These last, however, are still more frequent in the protube- 
 
SPINAL AND CEREBRAL LESIONS. 37 
 
 ranee, the pathology of which also approaches more nearly 
 that of the encephalon. Hemorrhage from rupture of mili- 
 ary aneurism, and softening by vascular obliteration, here 
 become frequent. 
 
 D. These considerations explain why the most common 
 anatomical localization in the encephalon is to be arrived at 
 chiefly through a knowledge of the vascular distribution ; 
 for the broken vessel being known, one can, as Lepine has 
 truly said, decide the outline and extent of the territory 
 involved. 
 
 This directs us once more to the field of normal anatomy, 
 for the purpose of obtaining some general ideas relative to the 
 vascularization of the encephalon. This is a subject worthy 
 of your entire attention, the more so that the questions relat- 
 ing thereto have been thoroughly investigated, and to this 
 your countrymen have contributed their share. 
 
 II. For the present it will suffice to examine the arterial 
 system, although lesions of the venous system have also a 
 marked influence upon the development of encephalic altera- 
 tions. The immediate object is to show by some examples 
 how important a profound knowledge of the normal conditions 
 of cerebral circulation is to the understanding of the majority 
 of anatomical lesions of the brain. 
 
 You remember the manner in which the trunks of the two 
 internal carotids and the two vertebral arteries join at the 
 base of the encephalon to carry on the circulation. 1 
 
 The internal carotids, as they leave the cavernous sinus, run 
 
 1 It is known that hemorrhage and softening of the brain are much more fre- 
 quent on the left than on the right side. Duret, in his memoire, thinks to have 
 discovered the anatomical solution of this fact in the manner in which the primitive 
 carotid and the vertebral arteries of the left side originate. The right carotid 
 arises from the innominate, and the innominate, at a considerable angle, from the 
 axis of the aorta, whereas the left carotid ascends nearly perpendicularly, and its axis 
 is more nearly continuous with the ascending aorta. It follows that a clot expelled 
 by a cardiac contraction would, by a direct line, be more apt to enter the left carotid. 
 The right vertebral artery rises from the horizontal portion of the subclavian 
 after it has made its curve ; the left vertebral artery, on the contrary, takes its rise 
 from the summit of the curve of the subclavian. 
 
3 
 
 DISEASES OF THE BRAIN. 
 
 perpendicularly to the base of the brain, and immediately 
 divide into two branches, the one anterior (the anterior cere- 
 bral), the other, running laterally, bears the name of Sylvian, 
 or middle cerebral artery (Fig. 8). Near their origin the two 
 anterior cerebral arteries are transversely united, and thus, in 
 a more or less complete manner, the circulation of the two 
 internal carotids are unified. That vascular arrangement con- 
 
 Verted. Arteries. 
 [ FIG. 8. Scheme of arterial circulation at the base of the encephalon. 
 
 stitutes a special system, to which may be given the name of 
 anterior system, or carotid system. 
 
 The vertebral arteries, directed obliquely from behind for- 
 ward, converge towards the median line and unite in a single 
 trunk, the basilar trunk. Towards the anterior border of the 
 protuberance, this basilar trunk separates into two branches, 
 
SPINAL AND CEREBRAL LESIONS. 39 
 
 called the posterior cerebral arteries, and these constitute a 
 second arterial system, the posterior, or vertebral system. 
 
 The carotid system and the vertebral system, united by two 
 vessels called the posterior communicants, and which are quite 
 variable in volume and arrangement, 1 form a vascular circle 
 at the base of the brain, known to all anatomists under the 
 name of the hexagonal, or better, the polygon of Willis. 
 
 At the anterior angles of the polygon of Willis are the two 
 anterior cerebral arteries ; from the antero-lateral angles, 
 running outwards, arise the two Sylvian (middle cerebral) 
 arteries, and finally, the posterior angle is formed by the 
 posterior cerebral arteries. This is the circle of Willis, and the 
 first two centimetres of those various arterial trunks give rise 
 to the nutrient arteries of the central ganglia, the corpora 
 striata and thalami optici. 
 
 There are six principal groups of these nutrient arteries. 
 
 The first antero-median group has its origin in the ante- 
 rior communicant and in the commencement of the anterior 
 cerebral arteries. The arterioles of which it is composed 
 nourish the anterior part of the head of the caudated ganglion. 
 
 The second postero-median group arises irom the pos- 
 terior half of the posterior communicants, and from the origin 
 of the posterior cerebral arteries. They nourish the internal 
 face of the thalami optici and the walls of the third ventricle. 
 
 The third and fourth right and left antero-lateral groups 
 composed of a larger number of arterioles, rise from the 
 Sylvian arteries and supply the corpora striata and the ante- 
 rior part of the thalami optici. 
 
 The fifth and sixth postero-lateral groups are derived 
 from the posterior cerebral arteries after they have passed 
 around the crura cerebri ; they nourish a great part of the 
 thalami optici. 
 
 A line surrounding the circle of Willis, two centimetres out- 
 
 1 Duret has directed attention to the frequent variations and anomalies of the 
 circle of Willis and the communicants. These last are often filiform and entirely 
 insufficient to re-establish circulation in case of obliterations. Certain forms of 
 anomalies explain also cases of softening of an entire hemisphere, by a clot obliter- 
 ating the internal carotid near its bifurcation. 
 
4O DISEASES OF THE BRAIN. 
 
 side of it, would include the origin of the ganglionic arteries, 
 and it might also be termed the ganglionic circle (Fig. 8). 
 
 The cortical regions (the convolutions of the cerebral hemi- 
 spheres) are irrigated by the large arteries which form the 
 angles and sides of the circle of Willis. 
 
 The anterior cerebral artery winds around the corpus cal- 
 losum, and spreads upon a portion of the inferior face of the 
 anterior or frontal lobe (gyms rectus andgyri supra- orbit ales] 
 and over a larger portion of the internal face of the hemi- 
 sphere (first and second frontal convolutions, prcecentral and 
 quadrilateral or prcecuneus lobules. ) 
 
 The posterior cerebral artery ', springing from the basilar, 
 winds around the corresponding cerebral peduncle, and divides 
 into three branches, which go to the inferior face of the brain 
 and to the occipital lobe (gyms uncinatus ; gyrus hippo- 
 campi ; second, third and fourth temporal convolutions ; the 
 cuneus ; lobulus lingualis). 
 
 The Sylvian (middle cerebral) artery is distributed to that 
 part of the frontal lobe which is not vascularized by the 
 anterior cerebral artery, and over the entire parietal lobe. 
 Later it will be necessary to follow in detail the distribution 
 of each of the four branches of this important artery, and to 
 describe exactly their vascular territories. 
 
 Such, then, is the general distribution of the arteries sent 
 to the internal, external, and inferior faces of the brain. To 
 understand the interior vascular arrangement it is necessary 
 to have recourse to various sections. Upon a single section 
 made within the domain of the Sylvian artery, the circulation 
 in the gray ganglia will seem to be confounded with that of 
 the surrounding gray matter and the subjacent white ganglia ; 
 that is but an illusion, however, which will be dispelled in 
 the next lecture. 
 
FIFTH AND SIXTH LECTURES. 
 
 ARTERIAL CIRCULATION IN THE BRAIN. 
 
 Summary : Labors of Duret and Heubner. Principal Arteries of the 
 Brain. The System of Cortical Arteries. Nutrient Vessels. System 
 of the Central Arteries, or of the Central Ganglia. Sylvian Artery ; 
 Its Branches; Arteries of the Central Gray Ganglia; Cortical 
 Branches ; Ramifications and Arborizations ; Nutrient Arteries of 
 the Encephalic Pulp; they are Long (Medullary Arteries) and Short 
 (Cortical Arteries). Effects of Obliterations of the Various Arteries. 
 Superficial Softenings, Yellow Spots Communication between the 
 Vascular Territories; Opinion of Heubner; Opinion ofl>uret. Ter- 
 minal Arteries (Cohnheim) Relative Autonomy of the Vascular 
 Territories of the Brain. Localizations of Cortical Lesions. Branch- 
 es of the Sylvian Artery ; Frontal, External, and Inferior. Artery of 
 the Ascending Frontal Convolution. Artery of the Ascending Parie- 
 tal Convolution. Artery of the Gyrus Angularis. Anterior and Pos- 
 terior Cerebral Arteries ; their Branches. 
 
 GENTLEMEN : 
 
 To-day I propose to examine more thoroughly the subject 
 which was barely introduced in our last lecture. If I have 
 clearly shown that in cerebral pathology it is the arterial 
 system which commands the situation, I must, as a matter 
 of course, through the same effort, have proved the necessity 
 of preliminary studies concerning the physiological connec- 
 tion between the circulation and the various departments that 
 compose the brain proper. 
 
 How, indeed, can one comprehend the rationale of hemor- 
 rhagic centres, or centres of softening, which constitute the 
 chief pathological anatomy of the brain, if he is not entirely 
 familiar with the special distribution of the arterial vessels, 
 an alteration in which is the commencement or the first con- 
 dition of these various lesions. 
 
 Unapplied facts in normal anatomy will not here suffice. 
 But the application of them at once suggests itself. I have 
 
42 DISEASES OF THE BRAIN. 
 
 already shown this, and I shall now exhibit it still more 
 clearly. 
 
 I pause at this point in the anatomy of cerebral circu- 
 lation, because that, even in the works most justly esteemed, 
 you will find on this subject only the most vague and en- 
 tirely insufficient information, quite inadequate to our needs. 
 
 All the precise knowledge which we have is of recent date, 
 and is the result of studies exacted through the needs of 
 pathological anatomy and physiology. 
 
 I shall borrow particularly from the important work of our 
 countryman, Duret a work which has been executed in the 
 laboratory of Salpetriere. Duret has encountered a rival in 
 his field. That rival is a German doctor, Heubner, professor 
 at the Leipzig University. These two authors, unacquainted 
 with each other, have pursued their researches simultaneously, 
 and in the most essential points they have arrived at identi- 
 cal results. That assuredly is a guarantee of the exactness 
 of the descriptions which they have given us. 
 
 In a recent work treating of syphilitic alterations in the 
 cerebral arteries, 1 Heubner professes to have been the initia- 
 tor. That is a claim which cannot be sustained. The first 
 researches of Duret relative to the circulation in the bulb and 
 the protuberance were communicated to the Societe de Bio- 
 logic in the session of Dec. 7, 1872. 
 
 By a remarkable coincidence, the same day, the 7th of 
 December, the resume of the researches of Heubner upon 
 cerebral circulation was published at Berlin in the Central- 
 blatt. One month after, in January, 1873, Duret published 
 a note in the Pr ogres medical* concerning that part of his 
 researches which treated also of the cerebral circulation. The 
 investigations of Duret are not, then, two years later than 
 those of Heubner, as the latter insinuates ; they are exactly 
 contemporaneous. Of this fact Heubner might easily have 
 convinced himself, as he has become acquainted with the last 
 memoire of Duret, published in the Archives de physiolo- 
 
 1 Die luetische Erkrankung der Hirnarterien, p. 188, Leipzig, 1874. 
 
 8 i8th and 25th of January, ist of February, 8th and i$th of November, 1873. 
 
ARTERIAL CIRCULATION IN THE BRAIN. 43 
 
 gie (1874), where the history of the question is given in de- 
 tail. 1 
 
 I have thought it well to insist upon this chronology, in 
 face of the annexation mania, in order to establish the large 
 part which belongs to our countryman. 
 
 I. I come to the special object of our studies. You know 
 the manner in which the three trunks, rising from the circle 
 of Willis, divide among themselves the arterial circulation in 
 each cerebral hemisphere. They are : ist, the anterior cere- 
 bral ; 2d, the middle cerebral or Sylvian artery, each rising 
 from the internal carotid ; 3d, the posterior cerebral, branches 
 from the basilar, a single trunk formed by the confluence of 
 the two vertebral arteries. 
 
 A. Each one of these arteries, in each hemisphere, com- 
 mands a special province ; I have already briefly acquainted 
 you with the general topography and limits of these main 
 vascular territories, and they should be examined not only 
 at the surface of the hemispheres, but also, by aid of sections, 
 in their interiors. 
 
 Our attention should first be given to the surface of the 
 brain, including the external, superior, internal, and inferior 
 faces, and secondly to frontal sections, which will demon- 
 strate the preponderating importance of the Sylvian territory. 
 
 We will soon see that these territories or provinces can be 
 divided into a certain number of secondary departments, 
 corresponding to the distribution of so many secondary ar- 
 teries emanating from the principal trunks. 
 
 B. Without stopping longer at this first general view, we 
 will enter at once into details. Each one of the .three prin- 
 cipal arteries gives rise to two very different systems of secon- 
 dary vessels. The first of these may be denominated the 
 system of cortical arteries. The vessels of which it is com- 
 
 1 The researches of Duret possess a considerable pathological interest, for they 
 have been made especially to explain the appearance of lesions found in autopsies. 
 With the aid of more than two hundred cases furnished him by Charcot, he has 
 been able to establish an anatomical classification of cerebral hemorrhages and 
 softenings. 
 
44 DISEASES OF THE BRAIN. 
 
 posed are spread through the pia mater, and there divide, 
 after a peculiar method, before furnishing the little vessels 
 which penetrate the cerebral pulp, and which are really the 
 nutrient vessels of the gray matter and the subjacent medul- 
 lary substance. 
 
 The second system is the central system, or the system of 
 the cerebral ganglia {gray central masses). The vessels of 
 which it is composed rise from each of the three principal 
 arteries close to their origin, and, in the form of arterioles, 
 plunge immediately into the substance of the ganglionic 
 masses. 
 
 The two systems, although they have a common origin, are 
 entirely independent of each other, and at the border of their 
 domains they have no point of intercommunication. 
 
 C. We must study the two systems in each of the main 
 vascular territories. In doing this we will observe both com- 
 mon and special traits. We will first examine the Sylvian 
 artery, the most important and the most complicated of the 
 three cerebral arteries ; after that the description of the two 
 others will be simple. 
 
 II. The Sylvian artery enters the fissure of Sylvius, the lips 
 of which must be separated in order to bring the vessel well 
 in view. But before this it furnishes from its superior border, 
 in a region called the anterior perforated space (locus perfo- 
 ratus antictis), a series of arteries which, running parallel to 
 each other, enter each of the channels of the perforated space, 
 which space is composed of the white substance (substantia 
 perforata) . These are the arteries of the central gray ganglia , 
 or more definitely, the arteries of the corpora striata. Let 
 us here examine the cortical system, leaving for the moment 
 the gray ganglia. 
 
 At the bottom of the fissure of Sylvius is seen the island 
 of Reil, on a level with which the Sylvian artery divides into 
 four branches, each of which deserves a special name. These 
 branches follow the furrows that separate the convolutions of 
 the island and to which they furnish vessels. They then bend 
 inwards and outwards, and rise again to the surface of the 
 
ARTERIAL CIRCULATION IN THE BRAIN. 
 
 45 
 
 hemisphere, where they are distributed, as we have just said, 
 over a certain number of fundamental convolutions, where 
 they form a number of little secondary territories correspond- 
 ing to each one of the convolutions. (Fig. 9.) 
 
 cowvol" , Ascending frontal convolution 
 
 j'S-- frontal convolution. ; 
 
 jl^frontal convolution 
 Ascending Iparietal conjrolTi <* a pT panef al lobule . 
 
 Trunk of, 
 Sylvian ar._.^ 
 Ext & inf r. frontal hrandh 
 Ascending frontal artery ,i 
 
 artery 
 
 yPanelo-sphenoidal & sphenoids! arteries 
 [Ascending parietal artery 
 
 FlG. 9. Distribution of Sylvian artery. (Partially schematic,} 
 
 We will not dwell, however, upon this description, but pro- 
 ceed to examine more thoroughly the manner in which the 
 cortical arteries are divided and distributed to the substance 
 of the pia mater before they penetrate the cerebral pulp. 
 
 I should mention that the branches arising from the Sylvi- 
 an artery immediately subdivide into branches of the third 
 order, to the number of two or three for each secondary 
 trunk. These tertiary branchlets constitute a kind of vascu- 
 lar skeleton, upon which is grafted a system of arborizations ; 
 that is a special and very original system of small vessels, 
 which arise not only from the extremities of the branches, but 
 also from the trunks themselves. 
 
46 DISEASES OF THE BRAIN. 
 
 Contrary to the assertions of most authors, Duret affirms 
 that these arborizations do not anastomose with each other, 
 although the branchlets sometimes communicate with those 
 of the neighboring territories. (Fig. 10.) 
 
 Medulla 
 
 .eaullary 
 hraiicEes 
 
 FIG. 10. Arterial division in the encephalon. (Duret.) 
 
 The ramifications and arborizations are on a plane with 
 the pia mater. On the internal face of that membrane they 
 give off the nutrient arteries, which enter the encephalic pulp 
 perpendicularly. The nutrient vessels here are all, according 
 to the definition of Ch. Robin, capillaries. This character 
 distinguishes them from the vessels of the central ganglia, 
 which bury themselves in the white substance of the base of 
 the brain (anterior perforated space), inasmuch as these last 
 retain the structure and dimensions of arteries. 
 
 By aid of sections which can be examined microscopically, 
 we will now investigate more closely the peculiarities of these 
 nutrient arteries. 
 
 Upon section of an entire convolution, made perpendicu- 
 larly to the surface, there appears, first at the periphery, the 
 gray substance which is like a festoon, having a thickness of 
 
ARTERIAL CIRCULATION IN THE BRAIN. 47 
 
 two or three millimetres ; next to this is the medullary sub- 
 stance composed of diverging andcommissural fibres, binding 
 one convolution to another. In such sections what is found 
 to be the arrangement of the arteries ? There can easily be 
 distinguished two kinds of nutrient arteries which have long 
 since been recognized by many authors, and particularly by 
 Todd and Bowman. Of these arteries one kind are long and 
 the other short. 
 
 1st. The long arteries, otherwise called the medullary ar- 
 teries, arise from the ramifications, or indeed are the terminals 
 of the arborizations. A dozen or fifteen may be seen upon 
 a section of a convolution ; three or four at the free surface ; 
 the others distributed upon the two slopes or in the separating 
 furrow. The arteries at the summit are vertical one of them 
 generally occupies the middle part of the convolution ; the 
 arteries on the slope are oblique ; those which occupy the 
 bottom of the furrow are again vertical. These arteries pene- 
 trate the centrum ovale to the depth of three or four centi- 
 metres ; they proceed without intercommunicating, except by 
 means of fine capillaries, and in that way constitute so many 
 little independent systems. At their terminations they ap- 
 proach the extremities of the central system of arteries, but 
 there is no communication whatever between the two systems. 
 
 Thus there exists upon the confines of the two domains a 
 sort of neutral ground where nutrition is less active. This 
 neutral ground is more especially the location of lacunal senile 
 softenings. 
 
 2d. The short nutrient or cortical arteries have the same 
 origin as the long ones, but they are finer and shorter, and 
 end, so to speak, on the road. Some run to the inner border 
 of the gray layer, to the edge of the medullary centre ; others 
 are of less extent, and terminate in the gray substance. These 
 short arteries give rise to capillary vessels which, conjoined 
 with those emanating from the long arteries, form a mesh or 
 web. 
 
 In the convolutions this network possesses the following 
 characters (Fig. n): 1st. The first layer has the thickness 
 of a half millimetre ; it is but slightly vascularized ; 2d. The 
 
48 DISEASES OF THE BRAIN. 
 
 second layer corresponds to two zones of nerve-cells ; there 
 the vascular network is very compact, and with very fine 
 polygonal interspaces ; 3d. At the edge of that layer the in- 
 terspaces become larger ; 4th. Finally, in the medullary sub- 
 stance the interspaces become still larger and vertically 
 elongated. 
 
 Arteries oftfie con-ex, 
 
 or grey substance * n 
 
 A. _ _ . _ ^,;Me<3ulIary 
 * /^Arteries, 
 
 Arteries of the comrmssural 
 fissure of GratioleL 
 
 FIG. ii. Arterial distribution in the cerebral cortex. 
 
 From the preceding facts it follows that, as concerns the 
 arterial distribution, the gray and subjacent white cortex are 
 a unit, since the vessels which they receive are derived in 
 common from the arteries which traverse the pia mater. 
 Should these last be obliterated at a given point, the gray and 
 white substance would suffer simultaneously in the correspond- 
 ing parts, and would be subject to that kind of mortification 
 called isckcemic cerebral softening. The reciprocal relations 
 of the parts permit a scheme of superficial softenings. 
 
ARTERIAL CIRCULATION IN THE BRAIN. 49 
 
 Recall the general distribution of the nutrient vessels. 
 They are directed parallel to each other like so many lines 
 towards the central parts. The white and the gray regions 
 of the cortex can then, as vascular departments, be divided 
 into a number of wedges, the bases of which are directed 
 towards the encephalon, and the apices towards the central 
 parts. This is, indeed, the form assumed by the greater 
 number of those softenings called superficial. That at once 
 calls to mind the appearance of infarctus of the spleen and 
 kidney. If the softening is an old one that is, of several 
 weeks' standing the gray substance appears depressed in 
 consequence of the destruction of its elements and the con- 
 comitant turning up of the subjacent white substance. 
 
 The superficial portions of the softening produce a yellow 
 spot. The yellow color belongs exclusively to the gray sub- 
 stance, the subjacent softened white substance being only 
 blanched, or sometimes lightly tinted with yellow. 
 
 A. In this case we have supposed the obliteration of a 
 branch of the second or third order. The obliteration of the 
 trunk of the Sylvian artery itself might produce necrosis of 
 all the gray cortex and of the subjacent white cortex also. 
 
 The central parts would be entirely spared if the oblitera- 
 tion occurred above the origin of the arteries of the corpora 
 striata. 
 
 B. It need not be supposed that all obliterations of this 
 kind would necessarily and surely produce such disastrous 
 effects. There are rare cases where, in fact, such obliteration 
 of a branch of the Sylvian artery, or even the artery itself 
 (I here take the Sylvian artery as example, it would be the 
 same for the anterior or posterior cerebral arteries) there 
 are cases, I say, in which the obliteration in question has no 
 appreciable, or, at least, but passing results. 
 
 If this be so, it follows that the three main vascular terri- 
 tories into which the brain is divided, and the departments 
 into which they in turn are separated, are not strictly isolated, 
 individual territories. They may communicate, and indeed 
 do communicate in the ordinary manner. But are these 
 communications easy and constant, or, on the contrary, are 
 4 
 
50 DISEASES OF THE BRAIN. 
 
 they accidental, indirect, and often impracticable ? In the 
 solution of this question authors are at variance. 
 
 Heubner holds that the communications in question are 
 very easy, that they are made by the mediation of vessels not 
 less than a millimetre in diameter. He rests that assertion 
 upon the results of injections, where he has invariably observed 
 that the material injected into any one of the departments by 
 the principal trunk, or by the branches, always rapidly pene- 
 trates the other territories. 
 
 He also cites pathological cases which indicate that obliter- 
 ation of one of the vessels of the cortical system or of its 
 branches has, during life, given no evident symptom ; cases 
 in which death having followed, the cerebral pulp in the parts 
 corresponding to the obliteration has at autopsy presented no 
 trace of softening. 
 
 In the first place, as to the pathological facts of Heubner, 
 we must recognize that they are real ; of this there is no 
 doubt. At the same time, to judge from the very numerous 
 observations which I have collected, they are certainly rare. 
 
 On the other hand, it is certain that in anatomy things are 
 far from being always as seen by Heubner. The observations 
 of Duret in that field have been numerous, and are nearly 
 always in accord. 
 
 Here is briefly what we learn from them : 
 
 Let ligatures be placed upon each of the three principal 
 arteries at the base of the encephalon on both sides, immedi- 
 ately above their origin in the circle of Willis. Then inject 
 the Sylvian artery. This will first fill the Sylvian territory, 
 and in the majority of cases it will pass beyond its limits. 
 The injected material invades the neighboring parts slowly, 
 little by little. This invasion is made from the periphery 
 inwards towards the centre of the invaded territory. It is 
 effected through the mediation of vessels of small calibre be- 
 longing to the system of ramifications having diameters of but 
 a quarter or a fifth of a millimetre, contrary to the opinion 
 of Heubner, who holds that these anterial vessels have a diam- 
 eter of one millimetre. 
 
 The number of anastomoses from territory to territory 
 
ARTERIAL CIRCULATION IN THE BRAIN. 51 
 
 are also quite variable. There are cases where one of the 
 three grand territories can be injected isolatedly, the anasto- 
 moses not being sufficient to permit the injection to enter the 
 adjacent territories. The communication which may occur 
 at the periphery of a vascular territory explains why the 
 obliteration of a main trunk often results in the softening of 
 only the central parts of the territory, the peripheral portion 
 remaining untouched. 
 
 Such are the conclusions of Duret, and to my mind they 
 are more in conformity with pathological facts than those of 
 Heubner. I should add that Cohnheim, who has also ex- 
 perimented in partial injections of the encephalic arteries, 
 agrees with Duret. He says if the arteries of the encephalon 
 are not final or terminal arteries (we will explain what Cohn- 
 heim means by that term), they very nearly approach that type. 
 
 Under the name of terminal or final arteries (Endarterien) 
 Cohnheim 1 ingeniously catalogues those arteries or arteri- 
 oles which, between their origin and the capillaries, neither 
 furnish nor receive any anastomosing branch. An example 
 of terminal arteries convenient for study is afforded by the 
 tongue of the frog, upon which it is easy, through the micro- 
 scope, to observe (de visit] all the effects of an obliteration. 
 You see upon these schematic designs the various conse- 
 quences of the obliteration of a terminal artery. The results 
 are, as it were, certain. If, on the other hand, we deal with 
 an anastomosing artery, generally the circulation is easily re- 
 established below the point of lesion, by means of anastomo- 
 ses. But these anastomoses may in their turn be obliterated, 
 and it so may follow that an artery which in its normal state 
 is not at all a terminal artery, may become so by accident. 
 
 The encephalic circulation furnishes a great many examples 
 of terminal arteries. Thus, without including the ramifica- 
 tions which exist in the pia mater, we can instance the nutri- 
 ent arteries. We see, too, that the arteries of the central 
 ganglia are entirely and rigorously constructed on that model. 
 The same type is found in all other circulatory systems where 
 
 1 Untersuchungen ueber die embolischeu Processe. Berlin, 1872. 
 
52 DISEASES OF THE BRAIN. 
 
 pathological or experimental lesions by vascular obliterations 
 usually result in what is termed infarctus. Such are the 
 spleen, the kidney, the lung, and the retina. None of the 
 viscera and this observation belongs to Cohnheim where 
 infarctus is not the rule, have the terminal mode of arterial 
 distribution. 
 
 But we will return to the relative individualities of the 
 vascular territories of the brain. Those individualities do 
 not belong exclusively to the large territories ; they are 
 found also in the secondary departments, which correspond 
 to the ramifications of arteries of the second and third order. 
 Between these regions of the secondary order, the same as 
 with the larger ones, communications are possible, but gene- 
 rally are very difficult. It follows that obliteration of one of 
 these secondary branches might have, and often does have, 
 the effect of inducing limited mortification in the cortex. 
 This is an important point in the study of cerebral localiza- 
 tion. It might be that a lesion thus limited would exactly 
 correspond to one of the convolutions, or to a group of convo- 
 lutions, endowed with specific properties, manifesting them- 
 selves during life through special phenomena. 
 
 You can readily comprehend that strict localization of 
 lesions of the cortex, produced by obliterations of arterial 
 branches of the second or third order, would be an especially 
 interesting study, when occurring in the Sylvian region. It 
 is in that large field that experimentation tends to place the 
 famous motor centres ; it is there also that clinical experience, 
 aided by pathological anatomy, has located the faculty of 
 articulate language. 
 
 So it is important that we should be well acquainted with 
 the principal branches rising from the Sylvian artery, and 
 closely examine their distribution in the fundamental convo- 
 lutions of that region. 
 
 The Sylvian artery divides into, or at least gives rise to, 
 four principal branches. The distribution of these branches 
 has been carefully studied by Duret and by Heubner. (See 
 Figs. 9 and 12.) 
 
 The first Duret calls frontal-external and inferior. That 
 
ARTERIAL CIRCULATION IN THE BRAIN. 
 
 53 
 
 is really the artery of the third frontal convolution (convolu- 
 tion of Broca). I have myself several times seen an oblitera- 
 tion of this arterial trunk produce a softening confined to the 
 
 'iQccipital 
 l loba 
 
 FIG. 12. Vascular territories of the superior cerebral surface. (Duret,) The 
 dotted lines indicate the territories of the anterior, middle and posterior arteries. 
 
 territory of the third convolution (in its posterior part). I 
 here add a conclusively corroborative fact. The case was 
 a woman named Farn .... observed at Salpetriere. She was 
 attacked with aphasia. There had existed no trace of paral- 
 ysis either of motion or sensation. Aphasia was in this case 
 
54 
 
 DISEASES OF THE BRAIN. 
 
 the only symptom, and atrophy of the third convolution was 
 also the only corresponding lesion revealed by autopsy. 
 (Figs. 13 and 14.) This is incontestably a fine example of cere- 
 bral localization. 1 
 
 The second branch of the Sylvian is the anterior parietal 
 artery of Duret. I prefer to term it the artery of the ascend- 
 ing frontal convolution (Fig. 9 and Fig. 12). 
 
 FIG. 13. Human brain, anterior lobe, left side. (Life size.) 
 
 The third is the posterior parietal artery, which I think 
 would be better named artery of the ascending parietal con- 
 volution (Fig. 9 and Fig. 12). 
 
 The fourth branch goes to the gyrus angularis and the first 
 sphenoidal convolution (Fig. 9 and Fig. 12). 
 
 1 We published the complete observations of that case in Nos. 20 and 21 of the 
 Progres Medical, 1874. 
 
ARTERIAL CIRCULATION IN THE BRAIN. 
 
 55 
 
 The two convolutions to which the second and third 
 branches of the Sylvian artery are distributed furnish, accord- 
 ing to the experiments of Ferrier upon the monkey, the mo- 
 tor centres of the limbs. You see that from the arterial dis- 
 tribution these two convolutions may suffer lesions independ- 
 ently of each other. 
 
 I do not know if the complete destruction of these two 
 
 FIG. 14. Human brain, anterior lobe, right side. (Life size.} 
 
 central convolutions has ever been seen, but here is a case 
 where entire destruction occurred of the ascending parietal 
 convolution, which in the monkey is, according to Ferrier, 
 the motor centre of the upper limbs, and partially so of the 
 lower ones. 
 
 In this case the convolution in question was replaced by a 
 depressed yellow spot. The frontal ascending convolution 
 
50 DISEASES OF THE BRAIN. 
 
 was not greatly altered, though it was manifestly atrophied. 
 Now, though the thalami optici and the corpora striata were 
 in that case uninjured their integrity was very explicitly 
 mentioned there existed a complete and permanent hemi- 
 plegia in the upper and lower limbs of the opposite side 
 (Fig. 15). 
 
 FIG. 15. Human brain, left side ; destruction of the ascending parietal convolution 
 and a great part of the frontal ascending convolution. 
 
 This is a result which contrasts singularly with those 
 accompanying two other observations relative to extended 
 lesions occupying other portions of the gray cortex of the 
 brain. In one case of limited destruction of the quadrilateral 
 lobule (yellow spot) there was no corresponding paralysis. 
 In another case, there was also a yellow spot which included 
 a large extent of the inferior face of the sphenoidal lobe, 
 which you know is arterialized by the posterior cerebral 
 artery. Here, also, in life there existed not a trace of 
 hemiplegia. 
 
 I think these examples, which I could easily multiply, will 
 suffice to convince you that some day not far in the future, it 
 will be possible to surely establish in the human subject the 
 doctrine of localization, at all events as concerns the super- 
 ficial parts of the brain. 
 
 After the description which I have given respecting the 
 Sylvian artery, I think I may be brief in that concerning the 
 
ARTERIAL CIRCULATION IN THE BRAIN. 
 
 57 
 
 subdivision into secondary department of the main cortical 
 vascular territories of the anterior and posterior cerebral 
 
 arteries. 
 
 Fiss, of .Rolando 
 
 cent, cony. 
 |Post.cettfc.cojiV. 
 
 **> 
 
 r*& 
 
 FIG. 16. Vascular territories of the internal or median face of the human brain, 
 indicated by the dotted lines. 
 
 III. The anterior cerebral artery is much less frequently 
 the seat of serious alterations than the Sylvian. That fact is 
 doubtless in part owing to the angle at which the Sylvian 
 leaves the internal carotid artery (Figs. 12, 16, and 17). 
 
 This artery gives three principal branches : the first nour- 
 ishes the two inferior frontal convolutions ; the second, much 
 more important, is distributed (less commonly than the 
 Sylvian, but much oftener than the anterior cerebral) to the 
 gyrus fornicatus (Fig. 16), to the corpus callosum, to the 
 first frontal convolution (internal and external faces), to the 
 paracentral lobule and upon the convex face of the frontal 
 lobe, to the first and second frontal convolutions (Fig. 17), 
 and finally to the superior extremity of the ascending frontal 
 convolution. The third branch of the anterior cerebral artery 
 is sent to the quadrilateral lobule, which may be subject to 
 lesions on its own account, as I have just now given you an 
 example. 
 
58 DISEASES OF THE BRAIN. 
 
 IV. The posterior cerebral artery (Figs. 12, 16, and 17) 
 often suffers alterations by embolismus and thrombus. 
 
 Ischaemic softenings of the posterior lobes are much more 
 common than with the anterior lobes. 
 
 The territory of this artery is divided into three secondary 
 
 FIG. 17. Vascular territories of the inferior face of the human brain, indicated by 
 the dotted lines. 
 
 departments, corresponding to three arteries of the second 
 order. The first of these goes to the gyrus angularis ; the 
 second to the inferior part of the sphenoidal lobe, embracing 
 the inferior sphenoidal convolution and the fusiform lobule ; 
 the third goes to the lingual lobule, to the cuneus, and the 
 occipital lobe proper. 
 
SEVENTH LECTURE. 
 
 CIRCULATION IN THE CENTRAL MASSES (GRAY GANGLIA 
 AND THE INTERNAL CAPSULE). 
 
 Summary : Arterial Circulation in the Gray Central Ganglia ; Intra- 
 Enccplialic Hemorrhage. Anatomico-Pathological Differences be- 
 tween the Peripheral and Central Parts of the Brain. Relative In- 
 frequency of Cerebral Hemorrhage in the Peripheral Regions ; its 
 Frequency in the Central Parts. Origin of the Arteries of the Cen- 
 tra,! System. Terminal Arteries; their Characters. Independence 
 of the Cortical and Central Arterial Systems. Analogies between 
 the Arteries of the Protuberance, the Bulb, and the Central Ganglia. 
 Their Mode of Origin Explains the Predominance in those Parts of 
 Arterial Ruptures. Branches Composing that System rise from the 
 Anterior and Posterior Cerebral Arteries and the Sylvian Artery. 
 Arrangement of the Gray Ganglia ; their Form and Relations. Con- 
 siderations upon the Internal Capsule ; its Constituent Parts (Direct 
 Peduncular Fasciculi, Indirect Peduncular Fasciculi, Diverging 
 Fasciculi). 
 
 GENTLEMEN : 
 
 In the preceding lecture I concluded the anatomico-medi- 
 cal description of the cortical arterial system of the brain. 
 I now purpose to call your attention to the arterial circu- 
 lation in the gray central ganglia. Under this term are 
 included the thalami optici, the corpora striata, and their so- 
 called appendages. This is a study which should receive our 
 closest care, for the phenomena which result from vascular 
 lesions in these ganglia are clinically of no less importance 
 than those which come from alterations in the arterial system 
 of the superficial or cortical parts of the hemispheres. We 
 will find in these central parts of the brain ischaemic altera- 
 tions such as belong to its superficial layers ; but, besides 
 these, we will there find, and upon a larger scale, lesions which 
 are rare upon the periphery. I refer to common intra-ence- 
 
60 DISEASES OF THE BRAIN. 
 
 phalic hemorrhage, one of the most constant anatomical 
 causes of those symptoms signified by the term apoplexy. 
 
 In this connection there exists a difference sufficiently in- 
 teresting to be noticed between the peripheral and central 
 parts of the brain. In the periphery, intra-encephalic hem- 
 orrhage is relatively rare, whereas in the centre it is common. 
 This is a fact of which the statistics of Andral and Durand- 
 Fardel are eloquent witnesses, and they are confirmed by 
 recent statistics. Thus, of 119 cases collected by Andral 
 and Durand-Fardel, the thalami optici and corpora striata 
 have been found the original seat of hemorrhage in 102 
 cases ; in only 17 cases has the hemorrhagic origin been either 
 in the anterior or posterior lobe or at the periphery of the 
 brain. On the other hand, ischaemic softenings of the brain 
 predominate, as Durand-Fardel truly says, in the periphery. 
 The facts which I have gathered at Salpetriere in every point 
 confirm these statements. 
 
 We will presently indicate some of the conditions necessary 
 to explain this remarkable contrast ; just now it is sufficient 
 to convince you that our review of the corticular arterial 
 system was a necessary introduction to the chapter upon 
 ischaemic softenings of the brain ; the studies which will oc- 
 cupy us to-day furnish the obligatory preface of the equally 
 interesting history of intra-encephalic hemorrhage. 
 
 I. You remember how the arterioles of the central system 
 are derived from the three great arterial trunks of the brain, 
 near their origin in the circle of Willis. The arteries which 
 form the central system are generally vessels of some size. 
 For the corpora striata they are, according to Duret, arteri- 
 oles measuring in diameter from a half to one and a half 
 millimetres. 
 
 Their mode of origin calls to mind the shoots rising from 
 the base of forest trees. I borrow the comparison from 
 Heubner, which, beyond its picturesque character, is quite 
 true ; only it must not be carried too far, for the arteries of 
 the central system, at their point of departure, take a direc- 
 tion perpendicular to the principal trunk. 
 
CIRCULATION IN THE CENTRAL MASSES. 6l 
 
 This perpendicular direction brings to mind that which we 
 have noticed respecting the nutrient arteries of the cortex. 
 But it is well not to forget that there is a difference between 
 the nutrient cortical vessels and the arteries of the gray cen- 
 tral ganglia ; the first, indeed, are but capillaries at least as 
 defined by Robin and the second, on the contrary, are ves- 
 sels of larger size. 
 
 Another character belonging to the arteries of the central 
 ganglia is that (as the term is used by Cohnheim) they are 
 terminal arteries par excellence. If the independency of the 
 vascular territories of the cortex is, as we have seen, open 
 to discussion, it is not the same respecting the central arteries. 
 Authors fully agree that they are entirely independent of 
 each other. 
 
 Thus Heubner says that by the aid of a Pravaz syringe 
 (its point blunted) one can inject each of the small arteries 
 that lead to the various parts of the corpora striata and 
 thalami optici. With all possible precautions, however, one 
 can never inject the entire body of the thalamus opticus or 
 corpus striatum. Only small departments of each can be 
 injected, and if the injection is made too forcibly, ruptures 
 are produced ; but notwithstanding that, the vascular territo- 
 ries keep to their assigned limits. 
 
 The multiplied experiences of Duret are to the same effect. 
 It should be added that under no circumstances can an injec- 
 tion be passed by way of the central arteries into the domain of 
 the cortical arteries, and the reverse is equally true the cen- 
 tral system cannot be injected through the cortical. 
 
 It is perhaps not without interest to notice the analogies in 
 the manner in which the nutrient arteries originate in the basi- 
 lar parts of the encephalon, in the protuberance, and even in 
 the bulb. 
 
 In the protuberance the resemblance is striking; the me- 
 dian arteries leave the voluminous basilar artery at right 
 angles and penetrate to the posterior part of the protuberance 
 parallel to each other and without anastomosing, reproduc- 
 ing somewhat the type of terminal arteries. 
 
 In the bulb the same method exists, but somewhat differ- 
 
62 DISEASES OF THE BRAIN. 
 
 ing through a special modification. The median arteries of 
 the bulb do not rise immediately from the great trunks of 
 the vertebral arteries ; they have their origin in the spinal 
 arteries. 
 
 This mode of origin and distribution of the arteries of the 
 protuberance and the central ganglia, possibly explains one 
 of the reasons (a mechanical one) of the predominance in 
 those parts of arterial rupture. 
 
 Remember that at the surface of the brain, where, as I 
 have said, hemorrhages are comparatively rare, the arteries 
 are not admitted to the pulp except after a long journey 
 through the pia mater, and after being transformed into very 
 slender vessels, in fact capillaries recall, I say, these peculiari- 
 ties, and you will much more easily comprehend the differences 
 which I have pointed out to you concerning the central 
 arteries. 
 
 1st. The distance from the heart to the large ganglia of the 
 base is very short. The arteries supplying these ganglia 
 come directly from the arteries forming the circle of Willis, 
 that is, from arteries of the third order from the heart. This 
 is evidently favorable to arterial ruptures. To be sure, this 
 is obviated to a certain degree by the right angle at the ori- 
 gin of the vessels, and also by a considerable reduction of 
 calibre. 
 
 2d. Compared with the cortical arteries, the central are 
 voluminous ; I allude especially to the arteries of the corpora 
 striata, which have a diameter of one-half to one and a half 
 millimetres. 
 
 3d. I would add that the absence of anastomosis seems an 
 unfortunate condition, for in case of increased pressure in a 
 vessel, the clearing of the way is impossible on account of 
 the absence of well-established collaterals. 
 
 The three great arterial trunks of the brain all take part in 
 the vascularization of the central regions, but that participa- 
 tion is very unequal. The anterior cerebral, for example, 
 sends only a few vessels to the head of the corpus striatum, 
 and even these inconstantly. The posterior cerebral artery 
 has a domain much more vast and important. It supplies 
 
CIRCULATION IN THE CENTRAL MASSES. 63 
 
 the thalami optici, and to a great extent the superior portion 
 of the crura cerebri and the tubercula quadrigemina. But 
 here, as in the cortical system, the Sylvian arteries incontesta- 
 bly play the preponderating role. These arteries furnish all 
 the branches which go to the caudated ganglion (with the 
 exception of a little field of variable branches from the ante- 
 rior cerebral) and to the various segments of the lenticular 
 ganglion. 
 
 We will consequently take the branches of the Sylvian ar- 
 tery for the type of our description. After that, it will be 
 easy to complete the description of the central nutrient sys- 
 tem with the addition of a few words concerning some 
 branches, derived, as may chance, from either the anterior 
 or posterior cerebral arteries. 
 
 II. But before entering into the detailed description of 
 these vessels it is very necessary to examine more closely 
 than we have hitherto done the parts to which they are dis- 
 tributed. In the preceding description we have done little 
 else than to name the parts, and in a summary manner to 
 indicate their general configuration. That rapid notice is 
 insufficient. We must enter into such examinations as are 
 necessary to the acquisition of a thorough anatomical knowl- 
 edge. 
 
 I need not repeat that it relates to those parts so interesting 
 as concerns the theory of cerebral localizations, namely, the 
 thalami optici, the caudated ganglion, the lenticular ganglion, 
 and the internal capsule. Such are the various constituents 
 which united form that which is called the central system, in 
 distinction from the cortical system. 
 
 Bring to mind how the crura cerebri, rounded at the point 
 where they border the thalami optici, flatten after having 
 passed it, internally and externally spreading forward and 
 backward like a fan. Upon that fan allow me to continue 
 the simile the ganglia of the gray substance are arranged as 
 follows : the thalami optici within and posteriorly ; within, 
 but before and above, the caudated ganglion ; outside of the 
 fan, and below the thalami optici and caudated ganglion, is 
 
64 DISEASES OF THE BRAIN. 
 
 situated the lenticular ganglion, which extends nearly as far 
 forward as the head of the corpus striatum, and backward 
 nearly as far as the posterior extremity of the thalami optici. 
 
 I only wish to indicate, en passant, the forms and principal 
 relations of the gray ganglia which I have enumerated. 
 
 I st. The thalamus opticus has a flattened, ovoid appearance. 
 The superior face looks upon the lateral ventricle, and the in- 
 ferior, which is also the internal, upon the middle ventricle. 
 On dissection it is with difficulty separated, on account of its 
 numerous and close connections with contiguous parts. 
 
 2d. The caudated ganglion has the form of a comma or 
 of a pyramid the large end 'of which is directed forward 
 and inward, the small end upward and outward. Its su- 
 perior face protrudes into the ventricle ; the so-called internal 
 face is mostly in contact with the superior portion of the in- 
 ternal capsule. This ganglion is very easily detached in 
 dissections, but in order to isolate it, the numerous fasciculi 
 which it receives from the internal capsule must be broken. 
 
 3d. The lenticular ganglion, although all its surface is cov- 
 ered, can easily and without much art be isolated from the 
 neighboring parts. Its general form is ovoid, with an an- 
 terior and a posterior extremity. There can be distinguished 
 in it two parts : (a) The anterior third, more obtuse, and com- 
 posed of a uniform mass of gray substance, is, at its very an- 
 terior extremity, confounded with the intraventricular nu- 
 cleus of the corpus striatum. (b) The second portion, the 
 posterior two-thirds of the lenticular ganglion, is flattened 
 from above downward in such wise as to offer an angle 
 turned inward towards the internal capsule. The internal 
 and superior face is intimately united to the internal capsule, 
 and the inferior face is parallel with the base of the brain. 
 The external face is in rapport with the external capsule, and 
 its intermediate with the front wall of the island of Reil. 
 The island lies close to it in its entire extent. An interesting 
 preparation consists in carefully removing successively the 
 gray substance of the convolutions of the island, the anterior 
 wall, and the external capsule, which lays bare the external 
 face of the lenticular ganglion. 
 
CIRCULATION IN THE CENTRAL MASSES. 65 
 
 In hardened specimens the separation between the external 
 face of the lenticular ganglion and the external capsule is 
 effected without art and with the utmost ease. This is be- 
 cause there are no medullary fasciculi and you see that 
 there are no vessels which bind the external capsule to the 
 third segment of the lenticular ganglion. 
 
 From the connections which we have outlined it might be 
 said that the three ganglia or gray central masses thalamus 
 opticus, caudated ganglion, and lenticular ganglion are in 
 some sense, as Foville has said, appendices to the internal 
 capsule, like cotyledonal prolongations of the crura cere- 
 bri. 
 
 On the side of the ventricles the thalami optici and the 
 caudated ganglia are isolated ; the lenticular ganglion is also 
 isolated, virtually, at least, on the side of the island. These 
 gray ganglia, then, form a distinct system from the other parts 
 of the brain, as well by their connections as by their mode 
 of vascularization. 
 
 Vertical sections will enable you to easily understand the 
 relations of the central parts. I will not at this point dwell 
 upon the structural details of the different ganglia, but will 
 return to them as occasion requires. Some examination and 
 idea of the construction of the internal capsule, however, is 
 indispensable. 
 
 The internal capsule, in part at least, is the prolongation, 
 not of the entire crus cerebri, but of the foot or crusta, the 
 inferior part only. The tegmentum or superior part, which 
 is separated from the foot by the locus niger, enters into rela- 
 tions especially with the tubercula quadrigemina and the 
 thalami optici ; it takes no direct part in the formation of the 
 internal capsule. 
 
 An old opinion held the internal capsule as a complete and 
 immediate emanation from the foot of the diverging fibres. 
 This is an error which Luys and Kolliker have corrected. 
 These authors have, in fact, demonstrated that the fibres com- 
 ing from the peduncle stop by the way to enter various 
 ganglia. I think, however, they have gone too far, in holding 
 that the internal capsule is entirely formed, ist, of diverging 
 5 
 
66 DISEASES OF THE BRAIN. 
 
 fibres which terminate in the ganglia ; 2<d, of fibres which 
 leave the ganglia and become diverging fibres. 
 
 From very delicate anatomical observations, Meynert, 
 Henle, and Broadbent have expressed the opinion that there 
 exists a third order of fibres which communicates directly 
 from the foot of the peduncle to the gray cortex. 
 
 The verification of the existence of these last fasciculi de- 
 pends, as you will see, upon certain pathological proofs. I 
 will cite, among others, some cases of descending degenera- 
 tions observed by Vulpian and myself. In the cases referred 
 to, destruction and yellow spots had largely invaded the 
 median convolutions, without concomitant alterations of the 
 corpora striata, and had produced progressive degeneration, 
 which could be followed across the isthmus and to the lower 
 region of the spinal cord. We are indebted to Gudden for a 
 series of experiments which I will later have occasion to 
 notice, and the results of which have the same bearing. 
 
 Henle l goes too far, perhaps, when he writes in his de- 
 scription of the nervous system that the internal capsule is 
 composed entirely of the fibres from the foot of the peduncle. 
 Certainly and we will have occasion to return to this sub- 
 ject both pathological and experimental facts in favor of the 
 existence of these fibres are numerous and important, and 
 the facts permit a belief (we will further on see the demon- 
 stration), that among the direct fibres some (the anterior) are 
 centrifugal and connected with movements of the limbs, 
 while others (the posterior) are centripetal and connected 
 with the transmission of sensorial impressions (Fig. 18). 
 
 To sum up, the internal capsule, according to modern re- 
 searches, 2 is composed as follows : 
 
 ist. By the direct peduncular fasciculi, which traverse the 
 capsule without entering the ganglia. 
 
 2d. By the indirect peduncular fasciculi. Of these some 
 are sent to the corpora striata, which they approach by the 
 inferior face ; others go to the lenticular ganglia, which they 
 
 1 Henle. Nervenlehre, p. 261. 
 
 9 Huguenin. Allg. Patholog. der Krankh. des Nervensystems ; Zurich, 1873, 
 p. 94, Fig. 70; p. 85, Fig. 63 ; p. 119, Fig. 82 ; p. 127. 
 
CIRCULATION IN THE CENTRAL MASSES. 6/ 
 
 penetrate by its first segment. Very numerous in this seg- 
 ment, they become less and less in the second and third seg- 
 
 Flbers of optic thalamus 
 extending to the periphery 
 
 Caudated nucleus 
 
 Kbers of caudated nucleus 
 extending to\the periphery 
 
 Jhrecb 
 fibers. 
 
 FIG. 18. Scheme illustrative of the different orders of peduncular fibres. 
 Huguenin. 
 
 ments, and to that unequal distribution is due the difference 
 in color of the three segments of the lenticular ganglion. 
 
68 
 
 DISEASES OF THE BRAIN. 
 
 There is no question as to whether the fibres from the foot 
 of the peduncle go to the thalami optici ; the thalami optici 
 receive no other fasciculi from the cerebral peduncles except 
 those from the tegmentum. 
 
 To the fasciculi which go from the foot of the peduncle to 
 
 Piters from the 2 Int. Segments of lent, nucleus, 
 
 Caudated nucleus/ 
 External portion of optic thalamiii/ 
 Int. portion of opti 
 
 Fibers from Che 
 \ tapetum. 
 
 \ /Int.Cap^ue,' ^?^ ^Anterior corrimbsure 
 X.., \ J '^'lenticular nucleus. 
 
 & Optic ganglion . yjasilar portion 
 
 Dlcaudatecl nucleus. 
 
 <|f Three layers of unnamed sub stance. 
 FIG. 19. Section of lenticular ganglion and its surroundings. (Ifeynert.) 
 
 the gray central ganglia are added, in the superior part of 
 the internal capsule, fasciculi which originate in the gray 
 ganglia, and go towards forming the diverging fibres that 
 run to the gray layer of the cortex. These fasciculi bear the 
 name of radiating fasciculi (StabkranzbUndet). There can be 
 distinguished, 1st, the diverging fasciculi of the corpora stri- 
 ata ; 2d, the radiating fasciculi of the thalami optici ; 3d, the 
 radiating fasciculi issuing from the lenticular ganglion, which 
 come principally from the superior border of the second and 
 third segments. 
 
CIRCULATION IN THE CENTRAL MASSES. 69 
 
 It follows from this exhibit that four orders of fasciculi enter 
 into the composition of the diverging fibres, and so attach the 
 internal capsule to the cortex of the convolution. 
 
 They are : 1st, the radiating fasciculi of the thalami optici ; 
 2d, those of the corpora striata ; 3d, those of the lenticular 
 ganglion these various fasciculi attach the gray central gan- 
 glia to the cortex ; 4th, the direct fasciculi which go from the 
 foot of the peduncle to the gray cortex without stopping in 
 the gray central ganglia. 
 
 In the internal capsule itself, and also in the foot of the 
 diverging fibres, one can recognize these various modes of 
 origin by submitting thin slices, properly hardened, to a low 
 power of the microscope ; to be sure, the research is not ex- 
 empt from difficulty. A little above that point, however, all 
 the fasciculi intermix in the most varied manner, either among 
 themselves, or it may be with the commissural fibres, in such 
 manner as to form an inextricable net-work, called the central 
 white substance. We will soon render an exact account of 
 the interest pertaining to this arrangement. 
 
EIGHTH AND NINTH LECTURES. 
 
 CENTRAL ARTERIES. ISOLATED LESIONS OF THE GRAY 
 
 GANGLIA. 
 
 Summary : Origin of the Arterial System of tlie Central Ganglionic 
 Masses. Unequal Participation of the Main Arteries of the Brain 
 Constituting this System. Description of the Striated Arteries; In- 
 ternal Striated Arteries; External Striated Arteries (Lenticnlo-Stri- 
 ated, Lenticulo-Optic). Terminal Arteries. Consequences of Obliter- 
 ations of Central Arteries Emanating from the Sylvian Artery. Soft- 
 ening of the Optico-Striated Bodies. Intra-Encephalic Hemor- 
 rhage. Regional Diagnosis. Isolated Lesions of the Gray Ganglia 
 without Participation of the Internal Capsule. Cerebral Hemi- 
 plegia, Central and Cortical. Lesions of the Internal Capsule. 
 "Variations of Symptoms according to the Spot in the Internal Cap- 
 sule Occupied by the Lesions. JYew Anatomical Considerations : Pe- 
 duncular Fibres going Directly to the Cortical Substance of the 
 Occipital Lobe ; their Role Relative to Sensibility. Proofs Fur- 
 nished, 1st, by Lesions of the Posterior Lenticulo-Optic Regions 
 of the Internal Capsule (Hemi.Anaesthesia Cerebral); 3d, by Ex- 
 perimentation. 
 
 GENTLEMEN : 
 
 I. You remember that the three great arteries of the brain 
 take an unequal part in forming the arterial system of the 
 central ganglionic masses. 
 
 A. (a.) Thus, the Sylvian artery very greatly predomi- 
 nates. It furnishes : 1st, in great part, the caudated ganglion ; 
 2d, the entire lenticular ganglion ; $d, a portion of the thala- 
 mus options ; 4th, the whole extent of the internal capsule. 
 
 (#.) The anterior cerebral artery has, on the contrary, very 
 modest attributes. It arterializes only the head of the cau- 
 dated ganglion, and even in this its participation is not con- 
 stant. 
 
 (c.) As for the posterior cerebral artery, its role is more 
 
CENTRAL ARTERIES. 
 
 important and tolerably characteristic. That artery, which is 
 extensively distributed (as it sends branches to the choroid 
 plexuses, to the ventricular walls, etc,), furnishes the following 
 regions of the central masses : 1st, the external and posterior 
 part of the thalami optici ; 2d, the tubercula quadrigemina ; 
 3d, the superior portions of the crura cerebri. 
 
 , Section of lafc. ventricle. 
 
 /ftigone pillar 
 
 'Caudated nudeua* 
 
 Ont . carjdt . artery, (L entinudeus of cojp .strialunid 
 
 lvian dfay.j tExt.capsule. 
 
 r 
 
 Int. arteries , 
 of corpus stratum. 
 
 Qiiasma of optic nervejsj. j 
 
 Grey substance of 3 -ventridf [Section of optic Land. 
 FlG. 20. Transverse section of the cerebral hemispheres, one centimetre posterior 
 to the optic chiasma. Arteries of the corpora striata. (Duret.) Vascular territories 
 indicated by dotted lines. 
 
 The plates (Figs. 20 and 21), on which the vascular ter- 
 ritories are separated by dotted lines, will make the details 
 clearer. 
 
 The description of the striated arteries alone requires some 
 explanation. With this you will possess, in brief, all that is 
 necessary to a knowledge of the central arteries, whether they 
 come from the anterior or the posterior cerebral arteries. 
 
 Emanating from the superior border of the Sylvian artery, 
 the striated arteries enter the apertures of the anterior per- 
 forated space, where they soon disappear from sight. But a 
 very simple preparation renders it possible to follow them in 
 the first part of their intracerebral course. I solicit attention 
 to the following description, because that, in order to under- 
 
72 DISEASES OF THE BRAIN. 
 
 stand some important facts, it is indispensable to know the 
 theory of common cerebral hemorrhage. 
 
 That exposition consists in destroying successively the 
 gray cortex of the island of Reil, the subjacent white sub- 
 stance, the anterior wall, and finally the internal capsule. 
 
 Lenticular ftud 
 
 Bora of .Anuiion 
 
 Sfhenoidal Horn 
 oCUUfentridA 
 
 Post, cerebral Arteries 
 
 FIG. 21. Vertico-transverse section of the human brain, posterior to the tuber- 
 cula mammillaria and anterior to the peduncles. Vascular territories indicated by 
 dotted lines. 
 
 Thus the entire external surface of the lenticular ganglion is 
 laid bare. If the preparation has been somewhat carefully 
 made, upon a well-injected brain and the preparation is 
 easily made, because, in its anterior part at least, the lenticu- 
 lar ganglion is as it were naturally detached from the internal 
 capsule one can follow the first part of the distribution of 
 
CENTRAL ARTERIES. 73 
 
 the principal striated arteries. By this artifice it is seen that 
 they spread like a fan at the surface of the gray ganglia. But 
 at a short distance from their origin they bury themselves in 
 the substance of the third segment, where they disappear. 
 
 Now, it is upon the transverse sections that one must fol- 
 low the ulterior distribution of the striated arteries. 
 
 A first section, made behind the chiasma (Fig. 20), shows 
 only the caudated and lenticular ganglia, the thalami optici 
 being more posterior. Upon that section are found the 
 deepest tracts of the arteries which we have just had under 
 observation. Besides these, other and smaller arterioles may 
 be discovered on the external surface of the lenticular ganglia, 
 and which may be termed internal ; after detaching them- 
 selves from the Sylvian trunk, they rise nearly perpendicularly 
 into the first two segments of the lenticular ganglion and the 
 adjoining parts of the internal capsule. 
 
 Of still greater interest are the external striated arteries, 
 those which, in the first part of their course, run over the 
 external face of the lenticular ganglia. They should be 
 divided into two groups : the first group is anterior, and the 
 arteries of which it is composed are the I enticulo- striated 
 arteries ; the second group is posterior, and the arteries which 
 constitute it are the lenticulo-optic arteries. 
 
 One of the arteries in the anterior group is especially 
 important on account of its size and its predominant role 
 in intra-encephalic hemorrhage ; it could be appropriately 
 called the artery of cerebral hemorrhage. After having en- 
 tered the third segment it traverses the superior portion of the 
 internal capsule, then enters the body of the caudated ganglion. 
 It then continues from behind forward to the most anterior 
 part of that ganglion. 
 
 The distribution of this striated artery, as well as that of 
 the lenticulo-striated arteries, should be studied from sections 
 made anterior to the one which has thus far served us. 
 
 The lenticulo-optic arteries are after the same model, only 
 after having traversed the most posterior part of the internal 
 capsule, they encounter the external and anterior part of the 
 thalamus opticus, over which they spread. 
 
74 DISEASES OF THE BRAIN. 
 
 I would remind you that we are dealing with terminal 
 arteries, and that if the injections are too strongly pressed 
 they will produce little ruptures upon different points of the 
 vascular tract, thus imitating in locality, as well as in form, 
 the centres of hemorrhage which are produced pathologically. 
 
 About the branches of the anterior cerebral artery, we 
 have nothing especial to say, except that they do not con- 
 stantly exist, and that they give place to very circumscribed 
 hemorrhages, though really grave, inasmuch as they often 
 open into the ventricles. 
 
 As for the posterior cerebral artery, I repeat that it merits 
 by itself more minute attention. I only wish to notice here 
 the arteries which it sends to the thalami optici. 
 
 These arteries are of two orders : 1st, the posterior internal 
 optic artery, arising from the posterior cerebral near its origin 
 at the basilar trunk, and which furnishes the internal face of 
 the thalamus opticus, and is capable in its ulterior tracts of 
 occasioning hemorrhages, of small extent to be sure, but 
 serious, as being often followed by ventricular inundation ; 
 2d, the posterior external optic artery, which comes from the 
 posterior cerebral after it has passed around the crus cerebri, 
 and in which it ascends obliquely before entering the posterior 
 part of the thalamus opticus. The rupture of this vessel 
 produces hemorrhage which often breaks into the body of the 
 crura cerebri. This artery deserves your close attention, for, 
 as you will see later, lesions within its territory produce a 
 train of symptoms altogether peculiar to themselves. 
 
 II. In journeying along we have gathered facts in the 
 highest degree interesting for the theory of cerebral patho- 
 logical localizations, and we will now examine these facts more 
 closely, commencing with those which concern the central 
 ganglionic masses. 
 
 A. (a.) The entire system of the central arteries emanating 
 from the Sylvian, may be obliterated in consequence of a 
 thrombus or an embolus of the principal arterial trunk. 
 Then follows softening of nearly the entire mass of the gray 
 ganglia, the district corresponding to the anterior cerebral 
 
CENTRAL ARTERIES. 75 
 
 and the posterior optic arteries alone being spared. Here is 
 a very concise localization, generally of an extreme gravity, 
 and which embraces, clinically speaking, all the pathology of 
 the ganglionic centres. The symptoms which belong to a 
 softening of the entire optico-striated bodies (the entire cen- 
 tral masses are sometimes so called) are none other than 
 common cerebral hemiplegia accompanied with cerebral hemi- 
 ancesthesia. 
 
 (b.) Analysis may be brought to bear on this complex 
 whole. We must not believe, however, that we are at present 
 able to recognize the special symptoms which belong to the 
 destruction of the thalami optici, the caudated ganglia, or the 
 lenticular ganglia, and still less to the various segments. 
 
 (V.) It is possible, however, by reason of the arterial distribu- 
 tion which we have described, that the anatomical locality 
 may betray itself by special symptoms, thus affording a re- 
 gional diagnosis. This is realized when the softening affects 
 all, or nearly all, of the territory of the lenticulo-striated arteries, 
 or that of the lenticulo-optic arteries. The two different events 
 differ in their symptoms ; the symptoms of hemianaesthesia are 
 present when the field of the lenticulo-optic arteries is invaded, 
 and absent when the lenticulo-striated arteries are the ones 
 involved. 
 
 B. That which has been said relative to ischaemic softening 
 is also applicable to intra-encephalic hemorrhage. This, you 
 know, is frequent, and especially in these regions ; the striated 
 arteries are, indeed, very prone to a special form of arterial 
 sclerosis which produces miliary aneurisms. One often ex- 
 tracts from a recent hemorrhagic centre a striate or an optic 
 artery, the prolongations of which have small aneurisms. 1 
 
 Contrary to current opinion, sanguineous effusion gener- 
 ally occurs (as Gendrin has long since recognized 2 ), in such 
 cases, not at first in the body of the corpus striatum it- 
 self, but outside of it to be more exact, in contact with the 
 external surface of the lenticular ganglion, between that and 
 
 1 See plate V. of Archives de physiologie, 1868. 
 
 2 A. N. Gendrin, Traite philosophique de medecine pratique, t. I., 1838. See 
 page 443, Nos. 789, 796; p. 465, Nos. 808, 809, 810; and page 478, No. 830. 
 
70 DISEASES OF THE BRAIN. 
 
 the external capsule, which becomes detached. Thus are 
 produced those flat centres which upon transverse sections 
 appear like narrow linear lacunae, nearly vertical, and parallel 
 to the gray ganglion of the front wall (Fig. 22). When the 
 sanguineous effusion is abundant the hemorrhagic centre 
 extends, especially transversely, and on account of the greater 
 resistance of the cranial walls and the wall of the island, the 
 central masses, enucleated so to speak, are crowded back en 
 bloc towards the ventricular cavity (Fig. 22). 
 
 L ateral Ventricle 
 
 norragic center / 
 
 destroying ext . capsule; 
 
 L enticulo - strata '-portion .of int. capsule* 
 
 FIG. 22. Extra-lenticular hemorrhagic centre, posterior to the optic chiasma. 
 { No hem iancesthesia . ) 
 
 I have given very ordinary cases, but it may happen also 
 that extravasation coming from the extremities of the termi- 
 nal arteries will occur in the body even of either the corpus 
 striatum or of the thalamus opticus. 
 
 Be that as it may, the only clinical localization possible in 
 these cases is, as in case of softening, those which corre- 
 spond to the lenticulo-striated or the lenticulo-optic domains. 
 
 The symptoms of hemorrhage are at present more difficult 
 of interpretation or of exact localizing than are those of 
 softening. Uninformed, one would be liable to attribute 
 
CENTRAL ARTERIES. 77 
 
 certain symptoms to the destruction of a part which really 
 was only the result of a neighboring accident. I allude to 
 compression, which, during effusion, however slight it may be, 
 never fails to somewhat affect the adjacent parts This is a 
 point to which I will shortly return. 
 
 III. The definitely acquired facts relative to regional diag- 
 nosis concerning the various parts which enter into the com- 
 position of the central ganglionic masses of the brain can be 
 reduced to a very small number of propositions. 
 
 1st. Regarding lesions confined to any one of the gray 
 central ganglia, and where the internal capsule is not in- 
 volved, we are not at present able, from clinical examination, 
 to recognize any special characters. 
 
 (a.) Thus it is impossible to distinguish, during life, a lesion 
 limited to the lenticular ganglion from one confined to the 
 caudated ganglion, and lesions of the thalamus opticus (though 
 upon this last point there is reason perhaps for some reserve) 
 generally confound themselves clinically with those produced 
 in the two compartments of the corpus striatum. 
 
 The symptoms which accompany lesions.Jimited to the 
 gray central ganglia are those of common cerebral hemiplegia. 
 That form of cerebral hemiplegia may be called central, to 
 distinguish it from motor paralysis, which sometimes results 
 from superficial lesions, and which in distinction I will call 
 cortical cerebral hemiplegia. 
 
 (#.) Paralysis, dependent upon lesions of the gray central 
 ganglia, is generally of motion only ; disturbances of sensa- 
 tion such as belong to cerebral hemiancesthesia are, however, 
 sometimes added, under special circumstances to which we 
 will shortly give attention. 
 
 (c.) Hemiplegia, dependent upon alterations confined to the 
 gray ganglia, is generally transitory, passing, lightly marked 
 not indelible, and in any case is at first comparatively 
 benign. It is understood that in formulating this proposi- 
 tion I remove all complications capable of greatly modify- 
 ing the picture ; such, for example, would be the eruption 
 of a hemorrhage, however small, into a ventricular cavity. 
 
78 DISEASES OF THE BRAIN. 
 
 Grave symptoms, such as early contractions, or epileptiforni 
 convulsions, almost necessarily ensue in such cases, and more 
 or less rapid death is generally the necessary consequence 
 of such complication. 
 
 The relative benignity of lesions limited to the gray ganglia 
 arises in part, doubtless, from the fact that these ganglia are 
 scarcely ever affected in their totality. Thus the caudated 
 ganglion, for example (and the fact is explained by the 
 method in which the vessels going to it are distributed), is 
 never destroyed in its entire extent, at least by itself, that is 
 to say, without the participation of the internal capsule or 
 other gray ganglia. On the other hand, the transitory char- 
 acter of a paralysis resulting from partial lesion of the cen- 
 tral ganglionic masses may indicate, as we will see, a sort of 
 functional supplement established between the various parts 
 of the caudated ganglion, or between the caudated ganglion 
 and the various segments of the lenticular ganglion. 
 
 2d. Then, again, lesions of the internal capsule, even when 
 strictly limited to the white tract, in no degree including the 
 substance of the gray ganglia these lesions, I say, generally 
 produce common cerebral hemiplegia of a very marked and 
 more or less persisting form. Thus, even when very circum- 
 scribed (principally when they are situated low down at the 
 side of the peduncle), these lesions produce a motor paralysis 
 almost necessarily accompanied by late contractions ; a symp- 
 tom of bad augury in these troubles, because as a rule it an- 
 nounces that the paralysis will resist all therapeutical means. 
 
 3d. It is proper to establish here an important distinction. 
 We have already said that the symptoms differ remarkably 
 according to the portion of the internal capsule affected by 
 the lesion. 
 
 If it occupies any part of the anterior two-thirds of the 
 capsule, the region where the white tract separates the ante- 
 rior extremity of the lenticular ganglion from the head of the 
 caudated ganglion, and which belong, as you know, to the 
 field of the lenticulo-striated artery, the paralysis will be ex- 
 clusively that of motion ; there will be no durable trouble of 
 sensation. 
 
CENTRAL ARTERIES. 
 
 79 
 
 On the contrary, if the lesion having invaded the domain 
 of the lenticulo-optic arteries should extend to the posterior 
 third of the capsule, in that region where it passes between 
 the posterior extremity of the lenticular ganglion and the 
 thalamus opticus, the presence of cerebral hemiansesthesia 
 would be almost certain. Most frequently the lesion extends 
 
 Posterior extremity, 
 of caudated jiucleus\ 
 B 
 
 Corpus CaHosum.and 
 illarS of the Arch. 
 
 .ateral Ventricle, 
 
 Extl.WalL 
 
 Horn of Amm 
 andsphenbidal 
 horn of lat.Yentricle: 
 
 'portion ihcWding 
 internal capsule). 
 
 External Capsule. 
 '^Lenticular Nucleus. 
 
 FIG. 23. Extra-lenticular hemorrhagic centre on a plane with the posterior por 
 tion of the thalamus opticus. ( Cerebral hemiancesthesia. ) 
 
 to several parts, and paralysis of sensation will be accom- 
 panied with a more or less marked motor hemiplegia. But it 
 may happen that cerebral hemianaesthesia will occur alone, at 
 least as a permanent phenomenon, in those cases, for example, 
 where the most distant parts, the most posterior portion of 
 the internal capsule would alone be definitely altered (Fig. 
 
 23). 
 
 In the preceding expose I have purposely alluded only 
 to truly destructive lesions of the internal capsule, to those 
 which, either by lacerations or necrosis, produce an irrepa- 
 rable loss of substance. It is necessary, however, to distin- 
 guish those cases where the internal capsule is not directly 
 involved, but affected by proximity to a neighboring phe- 
 nomenon, that is, the consequence of a lesion limited to the 
 
8o 
 
 DISEASES OF THE BRAIN. 
 
 gray ganglia which surround the capsules. Thus the disten- 
 tion of one of these ganglia, in case of interstitial hemor- 
 rhage, might compress the nerve- fibres that compose the in- 
 ternal capsule and so suspend their functions. But as the 
 nerve-fibres in such cases are only compromised and not de- 
 stroyed, the paralytic phenomena resulting from that com- 
 pression (excepting cases of tumor) would always be tempo- 
 rary. 
 
 The combination which I have brought to your notice is 
 frequently met in the clinic of intracerebral hemorrhage ; it 
 makes a somewhat complicated condition, and one in which 
 the interpretation of symptoms might be rendered difficult. 
 In this way, if one is not well forewarned of the difficulties, 
 
 Primitive lisemorragic center 
 in internal capsulej 
 
 arcle of prixnit^cUer. 
 Successive extensions from ihe center. 
 
 Zxt.Wall 
 Ext. Capsule 
 
 iteirial Capsule. 
 
 ICaudated nucleus of corpus strialum. 
 
 FIG. 24. Human brain. Section through the anterior portion of the internal 
 capsule, showing the location, mode of formation, and extension of hemorrhages at 
 the anterior portion of the internal capsule. (Hemiplegias.) 
 
 they would be tempted (and the error has often been com- 
 mitted) to attribute certain symptoms to destruction of some 
 one of the gray ganglia, as to the thalamus opticus, or the 
 
CENTRAL ARTERIES. 8 1 
 
 corpus striatum, which were only the result of a neighboring 
 accident and the incidental compression of the internal capsule. 
 
 The subject is worth further explanations. 
 
 Let us suppose the recent formation of a hemorrhagic cen- 
 tre in the lieu Selection. The blood would then be extrav- 
 asated outside of the lenticular ganglion, virtually into the 
 space of which we have already spoken ; and the third seg- 
 ment of the lenticular ganglion, otherwise called tine putamen, 
 would generally be in part torn away. I have told you that 
 under such circumstances the external wall of the extravasated 
 spot, including the convolutions of the island of Reil, the ante- 
 rior wall, and the internal capsule, would resist the pressure 
 of the extravasated blood, while the gray ganglia are gener- 
 ally crowded in their entirety towards the ventricular cavities. 
 It is clear that the substance of the internal capsule would 
 necessarily be more or less forcibly compressed by such a 
 change (Fig. 24). Respecting the symptoms produced, two 
 conditions might ensue. 
 
 Sometimes the extravasated centre is restricted to those 
 portions of the lenticular ganglion which correspond to the 
 anterior half or two- thirds of that body ; that is, to the domain 
 of the lenticulo-striated artery. In consequence, the anterior 
 part of tJie internal capsule would be immediately affected by 
 compression. The effect would be exclusively a motor hemi- 
 plegia of the opposite side of the body (Fig. 22). Sometimes, 
 generally extending from before backward, the extravasation 
 would crowd to the most posterior parts of the lenticular 
 ganglion ; pressure would then be made upon the posterior 
 part of the internal capsule, and symptoms of cerebral hemi- 
 anaesthesia would follow those of motor hemiplegia. 
 
 Figures 24 and 25 will enable you to easily recognize 
 the precise locality, and the mode of formation and exten- 
 sion of the various centres of central hemorrhage (see also 
 Fig. 23). 
 
 One word more upon the interpretation of these facts. 
 After having recognized during life the following symptoms ; 
 motor hemiplegia with hemianaesthesia, and at post-mortem 
 the existence of a spot involving the lenticular ganglion, 
 
82 
 
 DISEASES OF THE BRAIN. 
 
 would you be led to conclude from the close relation of these 
 two orders of facts that the lenticular ganglion controlled both 
 sensation and voluntary motion of the opposite side ? 
 
 Such conclusion would not be very legitimate, for, had the 
 patient survived, and the extravasation absorbed and left as 
 a representative only a yellow linear cicatrix, the hemianaes- 
 thesia, and even the motor paralysis, notwithstanding partial 
 destruction of the lenticular ganglion, would doubtless have 
 disappeared, leaving no traces. 
 
 Successive extension 
 of primitive center. 
 
 I 
 
 Tbgressrre extension 
 .of primitive center. 
 
 9 
 
 
 
 ernal capsuikL 
 
 FIG. 25. Human brain. Section through the posterior portion of the internal 
 capsule, showing location, mode of formation and extension of hemorrhages at the 
 posterior portion^of the internal capsule. (Hemiancesthesia. ) 
 
 That which has been said respecting hemorrhages of the 
 lenticular ganglion applies equally to hemorrhages which oc- 
 cur in the posterior portion of the bodies of the thalami op- 
 tici. These hemorrhages result from a rupture of the external 
 anterior optic, or lenticulo-optic artery. They are generally 
 indicated by a more or less marked hemiplegia, and nearly 
 always also by a more or less complete hemianaesthesia, pro- 
 vided the hemorrhage be sufficiently extensive. Should it 
 
CENTRAL ARTERIES. 83 
 
 be at once concluded (as so many authors have said and still 
 repeat) that the thalami optici are the seat of common sensa- 
 tion ? Incontestably, no ; besides, it would be easy to cite 
 numbers of facts where a hemorrhagic lesion of the posterior 
 tract of the thalamus opticus produced, in the first phase of 
 the malady (that is to say, when conditions of pressure existed), 
 sensitive and sensorial disturbances, which disturbances ceased 
 in the later stage, that is, from the date where reabsorption 
 removed the pressure from the posterior or lenticulo-optic 
 region of the internal capsule. 
 
 It would be superfluous to continue. I think I have suf- 
 ficiently demonstrated that in regional diagnosis, as concerns 
 the various parts of the central masses of the brain, it is the 
 participation or the non-participation of the anterior or pos- 
 terior regions of the internal capsule which determines the 
 situation. 
 
 IV. The propositions which I have offered possess a prac- 
 tical interest which will not escape your attention. Hitherto 
 they have been presented in the form of a postulate. It is 
 now proper to establish them by demonstration ; or, in other 
 terms, to give you that proof which will serve to insure them 
 a permanent place in the records of human pathology. 
 
 We ought also to give, as far as we can, the theory of the 
 facts concerned ; that is, we should enter as far as possible 
 into the anatomical and pathological reasons. To accom- 
 plish this, we are obliged to return once more to the normal 
 anatomy of the brain, in order to complete in some respects 
 the ideas already acquired. 
 
 In the preceding exposd, the predominant role in the patho- 
 logical anatomy of the central masses which is sustained by 
 the two main departments of the internal capsule, has been 
 shown, together with the proof, and they justify the descrip- 
 tions which we have made concerning the anatomical consti- 
 tution of the grand tract. Now, it is necessary to go a little 
 further, and seek for that which is peculiar to the anterior or 
 lenticulo-striated region of the capsule, in distinction from 
 that which is peculiar to the posterior, or lenticulo-optic re- 
 
DISEASES OF THE BRAIN. 
 
 gion, where lesions produce only symptoms of cerebral hemi- 
 ancestJiesia. We will commence with the last. 
 
 A. The recent anatom- 
 
 Peduncular fibres, going! 
 to Corpus striatum ; 
 
 Lenticular nucleus. 
 
 ical researches of Mey- 
 nert have furnished us in 
 this respect with very 
 important information. 
 They have been given in 
 detail in a work of one of 
 his auditors, Huguenin, 
 Professor at Zurich. 1 
 They consist of dissec- 
 tions and also in compari- 
 sons of thin slices, hard- 
 ened, and examined by 
 transmitted light. 
 
 The brain being placed 
 upon its base, the lateral 
 ventricles are opened in 
 such manner as to lay 
 bare the superior face of 
 the central masses those 
 which are contiguous to 
 the various parts of the 
 isthmus ; after that, by 
 minute dissection, are 
 PC ~ successively removed : 
 1st, tegmentum, or upper 
 
 part of the peduncle ; 2d, the tubercula quadrigemina ; 3d, 
 the entire thalami optici. 
 
 This being done, the inferior parts of the peduncle (pes 9 
 crusta) are brought to view, and higher up (in the region 
 of the internal capsule), the fasciculi of peduncular fibres run- 
 ning to the caudated ganglion. The fibres belonging to the 
 internal capsule, which goto the lenticular ganglion, occupy a 
 plane situated beneath and external to the preceding fasciculi. 
 
 Tasiculus^ol direct peduncular fibres 
 going to cortical substance of occip'l loBe. 
 
 1 Allgem. Path, der Krankh., etc., p. 119, Fig. 82, Zurich, 1873. 
 
CENTRAL ARTERIES. 85 
 
 Attentively observing the internal and posterior parts of 
 the diverging fibres thus exposed, there is to be discovered a 
 fasciculus, detached as it were from the main body, and which, 
 without entering the substance of the gray ganglia, turns 
 backward as soon as it reaches the inferior border of the len- 
 ticular ganglion (Fig. 26). 
 
 That, you see, is a direct fasciculus, since the fibres of which 
 it is composed enter the diverging fibres without stopping in 
 the gray substance of the central masses ; it is, moreover, as 
 the description shows, a separate fasciculus. 
 
 What is the destination of these nerve-fibres ? With man 
 it is nearly impossible to say ; but in some monkeys, accord- 
 ing to Meynert, their course can be easily followed into the 
 body of the white substance of the occipital lobe, just outside 
 the posterior cornu of the lateral ventricle (cor nu posterius, 
 ventriculi later alls}. They finally terminate in the body of 
 the gray cortical substance of the occipital lobe. 
 
 B. Does there exist any anatomical reason for supposing 
 that the fasciculus in question is really composed of centripetal 
 fibres, having as a function the transmission of sensitive im- 
 pressions to the surface of the posterior regions of the brain ? 
 Meynert so thinks, and for the reason that (according to him) 
 these fibres, by comparing thin slices, can be followed down 
 the length of the cerebral peduncle to the protuberance 
 (foot, inferior part) ; in the peduncle they occupy the most 
 external part. Reaching the protuberance, they go to the 
 posterior part of the pyramidal fasciculus, and maintain very 
 nearly the same location in the anterior pyramid to the point 
 of decussation. There (contrary to that which occurs with 
 the most internal fasciculi of the pyramid, which pass into 
 the lateral columns of the spinal cord) they decussate, and 
 then join the posterior spinal fasciculi. I am not able to guar- 
 antee the entire authenticity of the last part of the tract as- 
 signed by Meynert to the fibres which compose the most pos- 
 terior portion of the internal capsule. 
 
 Such is at present the share of normal anatomy, and it 
 affords an independent illumination of our subject. But how- 
 ever important this aid, it would, without pathological anat- 
 
86 DISEASES OF THE BRAIN. 
 
 omy and experimentation, be entirely insufficient to solve 
 the problem ; and once more we repeat that physiology and 
 pathology cannot be deduced from an unassisted contempla- 
 tion of pure anatomical facts. 
 
 C. We are now at the proper point to introduce clinical and 
 anatomico-pathological proofs. At the present time they are 
 abundant. It will suffice to note the observations of Ludwig 
 Tiirck, the pioneer in this road, 1 those of his compatriot 
 Rosenthal, 2 those which I have collected at the Salpetriere, 
 and finally those which have been gathered by Veyssiere 
 and Rendu, the first in his inaugural thesis, 3 the second 
 in his thesis for agregation* 
 
 The comparison of these observations gives the following 
 uniform results: 1st, that lesions confined to the posterior 
 lenticulo-optic region of the internal capsule necessarily result 
 in that form of hemianaesthesia which I call cerebral, and in 
 which sensations controlled by the cerebral nerves, that is, 
 the optic and olfactory nerves, are so affected as to faithfully 
 reproduce the characteristics of hysterical hemianaesthesia ; 
 2d, that on the contrary, in all cases where the lesions involve 
 only that part of the capsule which lies between the lenticular 
 ganglion and the head of the caudated ganglion, anaesthesia 
 is absent. 
 
 These contributions of pathological anatomy and clinic are 
 by themselves of incontestable and prime importance ; but 
 combined with the testimony of pure anatomy, they assume 
 a standard value. 
 
 That is not all ; experimentation has in turn brought its 
 share of facts, which also repeat the same story. 
 
 Under the guidance of pathological knowledge, experi- 
 mentation has corrected itself. It had previously been sup- 
 
 1 Tiirck, see Charcot. Lectures upon Maladies of the Nervous System, t. I., 2d 
 ed., p. 315. 
 
 2 Rosenthal, Klinik der Nervenkrankheiten, 2d Aufl., Stuttgart, 1875. 
 
 3 R. Veyssiere, Recherches cliniques et experimentales sur 1'hemianesthesie de 
 cause cerebrale. These de Paris, 1874. 
 
 * H. Rendu, Des anesthesies spontanees. These d'agregation, Paris, 1875, pp. 
 27 and 95. 
 
CENTRAL ARTERIES. 
 
 Lenticular nucleus 1 
 Section of ant. portion"* ! 
 .of internal capsule; | 
 Caudatedn{id,ei 
 A of corporal: 
 
 Inkcapsuk 
 
 posed that the centre of sensitive impressions was not in the 
 brain proper, nor in the thalami optici, but lower down, in 
 the protuberance, or perhaps in the crura cerebri. 
 
 Pathology controverted 
 that assertion, in showing 
 that a lesion situated above 
 those points, in certain re- 
 gions of the brain itself, was 
 quite sufficient to invariably 
 produce a total hemianaes- 
 thesia. Recent experimental 
 researches made by Duret 
 and Veyssiere, in the labor- 
 atory of Vulpian, have given 
 results also in conformity 
 with pathological teaching. 
 
 An ingenious instrument, 
 consisting of a trocar from 
 which at a desired moment 
 escapes a spring, is 
 duced through the cranial 
 wall into the central masses, to a depth and in a direction 
 calculated through previous experiments. Thus, with a little 
 experience, either of the two portions of the internal capsule 
 can by itself be injured. 
 
 If in these experiments the lesion reaches the posterior 
 capsule, hemiansesthesia of the opposite side of the body 
 certainly ensues ; generally there is associated with it a cer- 
 tain degree of motor paralysis ; this (motor paralysis), on the 
 contrary, occurs unaccompanied with anaesthesia whenever 
 the lesion is confined to any point of the anterior two-thirds, 
 leaving the posterior third of the internal capsule untouched. 
 (Figs. 27 and 28.) 
 
 Such in brief are the substantial results of these experiments. 
 
 After the foregoing, you will see that everything concurs to 
 establish the existence of direct fasciculi of centripetal nerve- 
 fibres in the posterior part of the internal capsule, having for 
 function the conduction of sensitive impressions coming from 
 the opposite side of the body towards the centre. 
 
 ilnt. cap&ula 
 of optic nerves, 
 
 FIG. 27. Transverse section of a dog's 
 intro- brain, five millimetres anterior to the optic 
 chiasma. 
 
88 DISEASES OF THE BRAIN. 
 
 Emanating from the foot of the central peduncle, these 
 fasciculi, as they leave the capsule, run directly towards the 
 formation of the diverging fibres, without communicating 
 with the gray ganglia of the central masses. Near their ori- 
 gin, that is, at the inferior part of the capsule, these fasciculi, 
 pressed into a narrow space, might be affected in great num- 
 
 Caudat^d nuclei 
 
 % Inf. capsule, post.portion. 
 
 FIG. 28. Transverse section of a dog's brain, on a plane with the tubercula mam- 
 millaria. ( Carville and Duret. ) 
 
 bers by a single stroke, by a very minute lesion, and be fol- 
 lowed by very marked anaesthesia. It can be understood, on 
 the other hand, that higher up, on a level with the foot of 
 the diverging fibres, a lesion of the same extent would, by 
 reason of the divergence of the fibres, produce much less 
 marked effects. This is, in fact, the case. There exist many 
 examples of well-marked hemianaesthesia in connection with 
 slight lesions of the foot of the diverging fibres. 
 
 It should now be determined if lesions extended to the 
 occipital lobes, and especially to their gray cortex, produce 
 crossed hemianaesthesia. Unhappily the facts which can be 
 cited in that regard are not sufficiently explicit, and the ques- 
 tion must remain in suspense until more ample information 
 is obtained. 1 However that may be, it is now recognized 
 
 1 In the observations which I have collected of superficial softenings of the 
 occipital lobe, there were frequent hyperaesthesias, painful sensations of all sorts 
 in the opposite limbs, hallucinations of vision, etc., as well as hemianaesthesia or 
 amblyopia. 
 
CENTRAL ARTERIES. 89 
 
 that the fasciculi which compose the posterior part of the in- 
 ternal capsule, and their direct emanations, cannot be con- 
 sidered as a centre of sensitive and sensorial impressions. 
 These fasciculi can only represent a highway, a cross-road, 
 where the centripetal fibres of which it is composed are all 
 represented before diverging to the superficial parts of the 
 brain. 
 
TENTH LECTURE. 
 
 CEREBRAL HEMIAN^STHESIA (CONTINUED). CROSSED AM- 
 BLYOPIA. LATERAL HEMIOPIA. 
 
 Summary t Resume of the Characters of Cerebral Hemianeesthesia. 
 Its Resemblance to Hysterical Hemian&esthesia. Anaesthesia In- 
 volves General Sensibility in its Various Forms, and also the Special 
 Senses. Hysterical Amblyopia. Ophthalmoscopic Examination. 
 Concerning Functions. Diminution of Visual Acuteness. Concen- 
 tric and General Contraction of the Field of Vision, etc. Crossed 
 Amblyopia with Hemianaesthesia from Cerebral Causes. Symptoms. 
 Lesions of the Cerebral Hemispheres which Produce Hemianaesthe- 
 sia Produce also Crossed Amblyopia and; not Lateral Hemiopia. 
 Hemiopia. Hypothesis of Semidecussation. Unilateral Homologous 
 Hemiopia. Varieties of Hemiopia. 
 
 GENTLEMEN : 
 
 In the last lecture I attempted to prove that a peculiar form 
 of hemianaesthesia is a necessary consequence of lesions in 
 the posterior regions of the internal capsule, or of its emana- 
 tions in the diverging fibres, no matter whether these lesions 
 be destructive, compressive, or suspensive, the value of which 
 last term I will soon explain. 
 
 I have based this proposition not alone upon pathological 
 and clinical anatomy, but also upon the facts of experimenta- 
 tion. I have given, too, some contributions from pure anatomy 
 which, to be sure, in certain respects, require confirmation, 
 but such as they now are, they permit us to look into the 
 mechanism by which the hemianaesthesia in question is pro- 
 duced. 
 
 There are some features relative to the totality of symptoms 
 and their anatomical and physiological interpretation, that I 
 have purposely left in shadow, so as not to overcrowd the 
 picture. I propose now to recur to them. 
 
CROSSED AMBLYOPIA. LATERAL HEMIOPIA. 9 1 
 
 I. First, let me in a few words recite the clinical characters 
 of that kind of hemianaesthesia which I propose to call cere- 
 bral hemiancesthesia, in order to distinguish it from all other 
 forms of obscuration or diminution of sensibility, the origin 
 of which is not recognized as depending upon a lesion of the 
 brain proper. 
 
 It is only lately that cerebral hemianaesthesia from gross 
 organic lesion " coarse disease" as H. Jackson, with a lib- 
 erty quite English, terms it has been the object of attentive 
 study. The picture it presents is exactly that of hysterical 
 hemianaesthesia ; this last, being at present better known, 
 will more naturally serve as a prototype. 
 
 Hysteria, you know, presents a unilateral anaesthesia. 
 Total anaesthesia is relatively rare. An antero-posterior plane 
 through the median line of the body marks the limit of insen- 
 sibility, which line upon the trunk, however, is somewhat 
 overstepped on the sternum in front, and on the spinal crest 
 behind. This is a detail of secondary importance. 
 
 The head, the limbs, and the body on one side, then, are 
 all affected at the same time. There may naturally be de- 
 grees in the functional disturbance, but more frequently it 
 embraces all kinds of common sensibility ; the sense of touch, 
 of pain, and of temperature are often simultaneously obscured 
 or suppressed. 
 
 The insensibility extends to the profound parts ; it affects 
 the muscles, which may be electrically excited without the 
 patient's consciousness of it. The mucous membranes are not 
 spared. Finally, let us add and this is the point which 
 above all others I just now desire to make prominent hemi- 
 anaesthesia does not include common sensation alone, it in- 
 volves also the sensorial apparatus of the same side of the 
 body affected with cutaneous anaesthesia, and that sensorial 
 hemiancesthesia takes in, not only the nerves coming from 
 the bulb, such as those of taste and hearing, but also the 
 nerves of smell and vision, the origins of which are in the 
 brain proper. 
 
 Such is the common picture of the hemianaesthesia of hys- 
 teria. If we compare the hemianaesthesia really cerebral 
 
92 DISEASES OF THE BRAIN. 
 
 with this, we will see a perfect resemblance, even to the 
 smallest detail. 
 
 We have already carefully brought to light the resemblance 
 as concerns common sensation, 1 and Magnan has done the 
 same in that which concerns troubles of hearing, smell, and 
 taste. 2 I see nothing to add to what has been said upon the 
 subject. Lately we have been more particularly occupied 
 with those phenomena which concern vision. In my service 
 at Salpetriere, Dr. Landolt has devoted himself to researches 
 in that direction, the results of which merit brief mention. 
 
 It seems to me of interest to offer some facts showing that, 
 even as relates to visual troubles (and this you will soon rec- 
 ognize as of great consequence), absolutely the same things 
 occur in real cerebral lesions as with those simply hysterical. 
 Abstraction seems to exhibit here its proverbial changeabil- 
 ity ; the unilateral amblyopia of hysterics differs in no essen- 
 tial character from the crossed cerebral amblyopia recognized 
 as having an organic origin. 
 
 Let us first examine hysterical amblyopia. 
 
 II. 1st. Here diminution more or less pronounced, and 
 sometimes (though rarely) absolute loss of vision upon the 
 side corresponding to the hemianaesthesia, is the first easily 
 recognized symptom. 
 
 2d. A more minute study develops the following peculiar- 
 ities : There exist in the bottom of the eye no alterations 
 appreciable by the opthalmoscope. The pupil and retina are 
 entirely normal. Comparative examination of the posterior 
 portions of the two eyes shows also no appreciable difference 
 in their vascularization. 
 
 If the ophthalmoscope does not betray alterations in am- 
 blyopia of hysteria, it is not the same with subjective func- 
 tional phenomena. This is what is learned through that 
 method of examination. 
 
 1 Charcot. Lectures upon Maladies of the Nervous System, ist ed., 1872. 
 3 Magnan. Upon Hemianaesthesia of General Sensibility and of the Special 
 Senses in Chronic Alcoholism. Gaz. hebd., 1873, pp. 729 and 746. 
 
CROSSED AMBLYOPIA. LATERAL HEMIOPIA. 93 
 
 3d. Visual acuteness, studied after ordinary rules, often 
 shows itself reduced by one-half or even more. 
 
 4th. There exists a general and concentric contraction of the 
 field of vision. 
 
 5th. Careful analysis has recognized certain peculiarities 
 which deserve attention ; they concern the concentric and 
 general contraction of the field of vision for colors. 
 
 Many authors, among others Galezowski, have heretofore 
 remarked the frequent accompaniment of achromatopsia and 
 dyschromatopsia with hysteria. These are the special points 
 of observation made in my service by Landolt. 
 
 I would recall to you that in the normal state, all regions of 
 the visual field are not, for some reason, equally apt in percep- 
 tion of colors. There are colors for which the visual field is 
 physiologically more extended than for others, and these 
 differences in the extent of the visual field always occur in 
 the same subject according to the same law for each color. 
 Thus the widest field of vision is for blue ; then yellow, then 
 orange, red, green, and lastly violet, which is only perceived 
 by the most central parts of the retina. Now, in the patho- 
 logical condition with which we are occupied, the normal 
 condition exists, though in various degrees exaggerated. 
 Indeed the various circles which in this investigation corre- 
 spond to the limits of vision for each color, are contracted 
 concentrically in a more or less marked manner, but still 
 based upon the law recognized for the normal state. 
 
 From this you can easily foresee the numerous combinations 
 which may arise in cases of hysteria where this kind of am- 
 blyopia has attained a high degree. The violet circle may 
 contract to nothing, then as the malady advances the same 
 will occur consecutively with the green, red, and orange ; 
 the yellow and blue remain to the last ; observation demon- 
 strates that these are the two colors for which sensitiveness 
 is longest preserved in cases of hysteria. Finally, in extreme 
 cases, it may happen that perception of all colors ceases, and 
 then to the eyes of the patient colored objects would all be- 
 come reduced to the appearance of a sepia drawing. 
 
 Such is the series of phenomena which we have over and 
 
94 DISEASES OF THE BRAIN. 
 
 over observed in hysterical amblyopia. Now, these are all 
 met with in their different shades, in various cases of crossed 
 amblyopia accompanied with hemianaesthesia and arising 
 from a lesion in the centre of the brain, such as we have re- 
 cently examined. The same is true of diminution of visual 
 acuteness ; of concentric and general contraction of the visual 
 field of colors, even where no pathognomonic lesions at the 
 bottom of the eye are appreciable with the ophthalmoscope, 
 etc. 1 
 
 I insist especially upon this last characteristic, because it 
 permits a clear separation of the functional trouble from those 
 usually caused by intercranial, organic lesions. I allude to 
 the alterations at the bottom of the eye, easily discovered 
 with the ophthalmoscope, and commonly known under the 
 name of papillary strangling or neuro-retinitis, and which is 
 so frequently seen as a consequence of encephalic tumors, 
 whatever may be their nature or location? and also following 
 various lesions acting more or less directly on the optic 
 bands. 
 
 In making known to you that crossed amblyopia is a con- 
 sequence of lesions within the brain, I have stated a fact of 
 major importance for the theory of cerebral localization. But 
 it cannot escape you that this fact is in formal contradiction 
 to generally diffused ideas. Indeed, if the theory put forth in 
 1860, by Alb. de Graefe, 3 and which still appears to hold un- 
 divided sway, as witness an interesting work recently pub- 
 
 1 New researches made for me by Landolt have demonstrated that contraction 
 of the field of vision for colors, in ovarian hysteria with hemiansesthesia, is always 
 experienced in both eyes at the same time ; only it is incomparably more pro- 
 nounced in the eye corresponding to the side affected with the anaesthesia. The 
 same peculiarity is encountered in all cases, which have been examined in this re- 
 spect, of cerebral hemiatuzsthesia arising from organic lesions. Therefore the 
 term crossed amblyopia, used in these lectures, will not be taken as absolutely 
 literal, since the obscuration of sight affects, unequally to be sure, both eyes. 
 
 2 See upon this subject the interesting work of Dr. Annuske. Die Neuritis 
 Optica bei Tumor Cerebri, in Arch, fur Ophthalmologie, 19 Bd., Abth. III., 
 I873. P- 165. 
 
 3 A. de Graefe. Gazette hebdomadaire, 1860, p. 708. See, also, Vortrage aus 
 der V. Graefe' schen Klinik. Monatsbl. f. Augenhlkde., 1865, Mai. 
 
CROSSED AMBLYOPIA. LATERAL HEMIOPIA. 95 
 
 lished by Dr. Schoen, 1 be credited, it is not crossed amblyo- 
 pia which determines exclusively unilateral lesions of the 
 brain, but a different visual trouble, namely, lateral homol- 
 ogous hemiopia ; in other words, a cerebral lesion of the left 
 substance of the brain should, according to the theory in 
 question, produce suppression or obscuration of the right 
 half of the visual field, and the reverse in case of a lesion in 
 the right half of the brain. 
 
 I believe that I can protest against this theory as being at 
 least too absolute, and I offer against it the following propo- 
 sition : cerebral lesions of the hemispheres zvhtch produce hemi- 
 an&sthesia produce also crossed amblyopia, and not lateral 
 hemiopia. 
 
 I am not prepared, let it be well understood, to decide that 
 lateral hemiopia is never the consequence of a lesion in the 
 substance of the brain, but I am disposed to believe that 
 such cases, if they really exist, are phenomena of contiguity 
 the effects, for example, of a more or less direct participation 
 of the optic bands. I do not believe that there now exists a 
 single observation clearly showing, except in this way, the 
 development of lateral hemiopia as a consequence of a lesion 
 of the posterior part of the internal capsule or the foot of 
 the diverging fibres, while a number of facts exist where such 
 a lesion has produced crossed amblyopia with all the charac- 
 teristics that we have just assigned to it. 
 
 III. We must give some details relative to the symptoms 
 of hemiopia and the presumed anatomical cause of its develop- 
 ment. 
 
 You know that this singular phenomenon, so often observed 
 in clinic, has long since suggested an anatomical hypothesis 
 according to which the optic nerves in man do not make a 
 complete decussation in the optic chiasma, but that which is 
 called a semidecussation. That hypothesis is an old one. It is 
 generally attributed to Wollaston, but it is really due to New- 
 ton y who expressed it in 1704, in his Treatise upon Optics^ and 
 
 1 Schoen. Archiv der Heilkunde, 1875, ist Heft. 
 
96 DISEASES OF THE BRAIN. 
 
 which Vater, in 1723, employed to explain three cases of hemi- 
 opia which had fallen under his observation. 1 I will recall the 
 hypothesis. 
 
 Among the nerve-tubes which form the bands of the optic 
 nerves there are those which, as has been said, decussate 
 in the chiasma and those which do not. (See Fig. 29.) 
 These last, that is, the non-decussating nerve-tubes, occupy 
 the external sides in the bands, in the chiasma, and also in the 
 optic nerves and the retina, whereas at all of these points the 
 fasciculi which decussate occupy the internal sides. It follows 
 that the non-decussating fasciculi, of the left band, for example, 
 being affected, would affect the left half of the retina of the 
 left eye, while the decussating fasciculi of the same band would 
 affect the left half of the right eye, the fasciculi of the right 
 optic bands operating of course after the same principle in- 
 versely. 
 
 In other words, the fasciculi which compose the optic band 
 of the left side would go to the left half of each retina, and 
 the reverse would occur with the nerve-fasciculi coming from 
 the optic bands of the right side. 
 
 It must be remembered that anatomically speaking this 
 arrangement of the optic nerve-fibres is entirely hypothetical. 
 If, indeed, various authors, among others Hannover, 2 Longet, 
 Cruveilhier, Henle, 3 and more recently Gudden, 4 have thought 
 themselves able to offer anatomical proof, there are others, 
 such as Biesiadecki, 8 E. Mandelstamm, 6 and Michel, 7 who con- 
 tradict it, and appealing to the same order of arguments 
 
 1 Knapp. Archives of Scientific Medicine, New York, 1872. 
 
 2 Hannover. " Das Auge," Beitrage zur Anatomic, Physiologic, und Patholo- 
 gic dieses Organs, Leipzig, 1872. 
 
 3 Henle. Nervenlehre. Ueber die Kreutzung im Chiasma Nervorum Optico- 
 rum. 
 
 4 Gudden. Arch, fur Ophthalmologie, 1874, t. 20, 2d Abth. 
 
 5 E. Biesiadecki. Ueber das Chiasma Nervorum Opticorum des Menschen und 
 der Thiere. Wiener Sitzber. d. math. Naturwiss. Classe B., d. 42 Jahrg. 1861, 
 p. 86. 
 
 6 E. Mandelstamm. " Ueber Sehnervenkreuzung und Hemiopie." Arch, fur 
 Ophthalmologie, t. 16, 1873, p. 39. 
 
 1 Michel. Ueber den Bau des Chiasma Nervorum Opticorum. Same work, p. 
 59, Taf. I., Fig. IV. See also Bastian, The Lancet, 1874, July 25, p. 112. 
 
CROSSED AMBLYOPIA. LATERAL HEMIOPIA. 
 
 97 
 
 attempt to demonstrate that the nerve-fibres of the optic 
 nerves, even in man, submit to a complete decussation. In 
 short, it may be said that at present the question is far from 
 being settled. I repeat that the semidecussation is only 
 an hypothesis ; but that hypothesis explains, far better than 
 any of its substitutes, all the facts observed in clinic. In the 
 scheme herewith given it will be seen how easily it serves to 
 interpret the various modes of hemiopia. (Fig. 29.) 
 
 Sfemi- decussation in chiastna., 
 Xfisionfiere would produce temporal.hemiopia.i 
 
 litres decussating in -chiasma 
 
 ^on-decussating fibres in-chiasma, 
 
 I esloTL here .pro duces nasal heml 
 
 L esion of optic ancL 
 producing right lateral 
 hemiopia 
 
 right eys 
 /"// running' to leflliemispli^ref 
 
 .esionJiece.pMaiacea nasal "hemlopia 
 
 I eft Hemi sphere . Lesion 
 here would produce crossed?, 
 light atnbtyupia . \\ 
 
 Tibree from rigKl \\ 
 eye . ending in left ^hemisphere 
 
 lemisphere. 
 'J)ecussation Lack of genicular todies* 
 
 FIG. 29. Scheme to explain the phenomena of lateral hemiopia and crossed am- 
 blyopia. 
 
 We will first consider unilateral homologous hemiopia, that 
 which, according to writers, can occur only as the direct con- 
 sequence of an intracerebral lesion of the brain. It is clear 
 that according to the theory, a lesion situated at 5 in such 
 way as to interrupt the tract of the fasciculi of the left optic 
 band, those fibres which crossed in the chiasma (d), and also 
 7 
 
98 DISEASES OF THE BRAIN. 
 
 those which did not cross (a), would result in affecting the left 
 half of each retina (//), in other words, might obscure or 
 completely suppress the entire extent of the visual field of the 
 right side (lateral right hemiopid}. Lateral left hemiopia 
 would ensue from a lesion affecting in the same manner the 
 optic band of the right side. 
 
 Thus speaks theory ; as for facts, there are numerous ex- 
 amples which demonstrate that lateral hemiopia is really the 
 consequence of a lesion bearing upon one of the optic bands. 1 
 The effect will remain the same, no matter upon what part 
 of the band, between its origin in the genicular body and its 
 termination in the chiasma, the lesion occurs. Lateral hemio- 
 pia may also be produced not only by a lesion in the band 
 itself, but also as a contiguous phenomenon in consequence 
 of lesions hemorrhage or tumors developed in parts which 
 are in more or less immediate relation with the tract, such, for 
 example, as the lower part of the cerebral peduncle (pes) or in 
 the pulvinar. 
 
 Other modes of hemiopia are not difficult to interpret. A 
 lesion, a tumor, for example, situated at (3), that is, upon the 
 median part of the chiasma in such way as to involve only 
 the decussating optic fibres (c, d) might paralyze the left 
 
 (1) half of the retina of the right eye as well as the right half 
 
 (2) of the retina of the left eye, and so produce what is called 
 temporal hemiopia. Saemisch foretold, in a case of this 
 kind, while the patient still lived, that such was the location 
 of the lesion, and autopsy fully justified his prediction. 2 
 
 On the contrary, that hemiopia, called nasal, characterized 
 by the suppression of the median portion of the field of vision, 
 would be produced if the course of the direct fibres (a, b) 
 only were interrupted, at the chiasma, for example, in conse- 
 quence of lesions occupying each side symmetrically at the 
 points (4, 4). This is a combination which is indeed rare. 
 There exists, however, some examples ; among others one 
 
 1 See, among others, the case of E. Miiller in the Arch, fiir Ophthalmologie, 
 VIII. Band i, S. 160. 
 * See also E. Muller in Meissner's Jahresbericht, 1861, S. 458. 
 
CROSSED AMBLYOPIA. LATERAL HEMIOPIA. 99 
 
 carefully described by Knapp. 1 In this case it resulted from 
 a pressure upon the points indicated, by the anterior cerebral 
 arteries and the posterior communicant artery enlarged and 
 indurated by an atheromatous degeneration. 
 
 I will dwell no longer upon these forms of hemiopia, which 
 do not at present directly interest us, but return to lateral 
 hemiopia. It seems an established fact that this visual trouble 
 is the necessary result of a lesion of the optic bands ; it is 
 also generally affirmed to be the necessary consequence of a 
 lesion which may affect the optic nerve-fibres beyond the 
 corpora geniculata (7) in their deep intracerebral tract (in 8, 
 9). In my opinion, clinical and pathological anatomy con- 
 tradict that assertion at all events, when made in too absolute 
 a manner ; and in this respect I can but repeat that which I 
 just now have said; I do not believe that there now exists 
 a solitary observation showing, beyond doubt, the develop- 
 ment of lateral hemiopia in consequence of an intracerebral 
 lesion outside of all participation of the optic tracts , whereas 
 facts exist where a lesion of the posterior part of the internal 
 capsule, or the foot of the diverging fibres, has produced 
 hemianaesthesia, and at the same time crossed amblyopia, a 
 visual trouble very diverse from hemiopia. 
 
 That being the case, how can we understand, in a sche- 
 matic view, that effect of a cerebral lesion, while at the same 
 time we recognize the incontestable fact of hemiopia being 
 the consequence of a lesion of the optic bands ? 
 
 To this end a slight modification of the common scheme 
 will suffice. It is generally admitted that the nerve-fibres 
 coming from the right eye and the left eye which compose 
 each of the optic bands continue their course beyond the 
 corpora geniculata uninterruptedly into the very depths of the 
 corresponding hemispheres, and that view accords with the 
 prevailing idea that a lesion of the optic nerve-fibres in their 
 intracerebral course is equivalent to a lesion of the optic 
 bands, and consequently produces hemiopia. 
 
 I propose to admit, on the contrary, that only the fasciculi 
 
 1 Arch, of Scientific and Practical Medicine, 1873, p. 293. 
 
100 DISEASES OF THE BRAIN. 
 
 of the bands which decussate in the chiasma (c, d) reach their 
 profound depths, whatever they may be, without new decus- 
 sation ; whereas the direct fasciculi do completely decussate 
 beyond the corpora geniculata, before entering into the 
 depth of the hemispheres (8, 9) ; this occurs upon an undeter- 
 mined point of the median line, perhaps in the tubercula 
 quadrigemina. From that arrangement it would result that 
 the fasciculi (b, d), reunited, for example, in a point of the 
 left hemisphere (8), would represent the totality of the fibres 
 coming from the retina of the right eye, and that the fasciculi 
 (a, c) would represent the totality of fibres coming from the 
 left eye. The optic fibres, according to that, in their pro- 
 found course, are at length all reduced to the type of com- 
 plete decussating fibres, and one can comprehend that, in an 
 apparatus so constructed, a lesion of the optic bands would 
 produce lateral hemiopia, although a lesion situated deeply 
 in the substance of the brain would to the contrary produce 
 crossed amblyopia. 
 
 I give you this hypothesis for whatever it is worth. At 
 present it has no anatomical base. But at all events it fur- 
 nishes, if I am not deceived, an easy means of very simply 
 representing the tolerably complex facts revealed by clinical 
 observation. 
 
ELEVENTH LECTURE. 
 
 ORIGIN OF THE CEREBRAL PORTION OF THE OPTIC 
 
 NERVES. 
 
 Summary : Relations of Crossed Amblyopia and Sensitive Hcmi- 
 aneesthesia, Resulting from a Lesion of Hie Internal Capsule. 
 Cerebral Origin of the Optic Nerves. Diverging Fibres of Reil. 
 Radiating Cortico-optic Fasciculi. Anterior Fibres (Anterior Roots 
 of the Thalami Optici) ; Middle Fibres (Lateral Expansion) ; Poste- 
 rior Fibres (Cerebral Expansion of the Optic Nerves) ; Anatomical 
 Relations between the Cerebral Expansion of the Optic Nerves and 
 the Centripetal Portions of the Radiating Fibres (Sensitive Hemi. 
 anaesthesia). Optic Bands. Origin of the External Root (Thalami 
 Optici); External Genicnlate Bodies, Anterior Tubercula Quadri- 
 gemina. Origins of the Internal Root (Internal Genicnlate Bodies, 
 Posterior Tubercula Q,uadrigeinina). Relation between the Mass 
 of Gray Substance and the Gray Cortex of the Encephalon. Cortico- 
 optic Radiating Fasciculi. Effects of Lesions of the Anterior Tu- 
 bercnla Q,uadr igemina. Facts of Lateral Hemiopia of Supposed 
 Intra-cerebral Origin. 
 
 GENTLEMEN : 
 
 I hope that I have demonstrated the existence of crossed 
 amblyopia as a symptom of lesion in the posterior part of the 
 internal capsule, or of the corresponding irradiations of the 
 foot of the diverging fibres. 
 
 At the same time I have attempted to prove de Graefe's 
 proposition, that homologous hemiopia might be (crossed 
 amblyopia excluded) the only functional trouble of vision 
 following a lesion of the cerebral hemispheres, to be at least 
 too sweeping, and that the arguments upon which it rests 
 ought to be completely revised. 
 
 I now wish to examine whether normal anatomy can ex- 
 plain why the sensorial trouble in question, that is, crossed 
 amblyopia, is a frequent, as it were habitual, accompaniment 
 
102 DISEASES OF THE BRAIN. 
 
 of sensitive hemianaesthesia resulting from a lesion of the in- 
 ternal capsule. 
 
 This hemianaesthesia of common sensibility, you remember, 
 may be produced through the existence of a fasciculus of 
 direct centripetal fibres, that is, fibres not stopping in the 
 gray ganglia of the central masses, and which, upon issuing 
 from the internal capsule, form the very posterior portion of 
 the diverging fibres. 
 
 Does there exist a connection, a more or less immediate 
 relation, between that sensitive fasciculus and the sensorial 
 fasciculi designed to put the apparatus of vision in communica- 
 tion with the gray cortex of the brain ? To enter upon this 
 question it is first necessary to study the origin of the pro- 
 found or cerebral part of the optic nerves. We will examine 
 this difficult subject, which is still obscure in more than one 
 point. I must not, however, omit giving you the principal 
 outlines, if only to indicate the direction in which our future 
 researches should be made, and where pathological anatomy 
 will very likely be called to play a dominant part. 
 
 According to the general plan, the encephalic nerves ought 
 to encounter, before penetrating the brain itself, one or more 
 masses of gray substance, Avhich it is agreed to call the gan- 
 glions of origin, and the expansions arising from these ganglia 
 put these nerves in an indirect rapport with the gray cortex 
 of the cerebral hemispheres. 
 
 A priori, there is nothing to induce belief that the optic 
 nerves escape the rule. In fact, they do not escape it, but 
 their distributions are very complicated and ill-known, espe- 
 cially in some of the details. 
 
 I. I will pause an instant to note the construction of a por- 
 tion of the diverging fibres of Reil. 1 
 
 1 The various fasciculi, peduncular or otherwise, which form the diverging fibres, 
 (fibres convergentes of Luys) (systZme de projection de i r ordre of Meynert) com- 
 pose the greater portion of the white central mass called centrum ovale, which the 
 gray cortex of the hemispheres envelops and encloses like a purse. They, how- 
 ever, do not represent the totality of that mass. It contains, beyond these, fasci- 
 culi entirely foreign to the preceding, but which mix with them. These last fasci- 
 culi constitute that which Meynert calls the system of association. One may 
 distinguish in a general way the two orders of fasciculi which compose this system. 
 
CEREBRAL PORTION OF THE OPTIC NERVES. 
 
 103 
 
 In the scheme which I present to you and which is bor- 
 rowed from Huguenin (loc. cit. , pi. 69, page 93), the ablation 
 
 Ltoflent.nudeus., 
 
 PiLeis uniting two convols, i T .! . 
 
 a* 1 ) j Fasjculus arcuattis. 
 
 Tasicrulu^ JongiUid.in ' 
 
 Pulvfnar.''' ; / 
 Horn of Ammok / 
 
 ExLeriLCorpora geniculata'. *./." ' a L^ ., 
 
 Pos't.horn of -latyentricle. 
 
 Caniatedextr. of. corpus slriat'um. 
 
 FIG. 30. Antero-posterior section of a monkey's brain (Cercocebus cinomolgus} 
 showing the connecting fibres of the brain. (Meynert, Strieker's Hand-book.) 
 
 of the superior parts of the hemispheres, including the corpus 
 callosum, has laid bare the ventricular cavities. You will 
 
 One kind consists of commissures which unite the homologous parts of the two 
 hemispheres. Such, for example, are the corpora callosa and the anterior com- 
 missure. The others are composed of fibres having a general antero-posterior 
 direction, which bring into relation the various points of the same hemisphere. 
 Fig. 30, borrowed from Meynert (loc. cit., Fig. 233), representing the anterior 
 section of the brain of a monkey {Cercocebus cinomolgus], very well exhibits the 
 direction of the principal fasciculi of the antero-posterior system of association. 
 There are to be seen the fibres uniting two convolutions (fibra proprice), well 
 described by Gratiolet, the fasciculus arcuatus, the fibres of which extend beneath 
 the corpus callosum from the occipital to the frontal lobe ; the inferior longitudinal 
 fasciculus which joins the occipital lobe to the extremity of the sphenoidal lobe, and 
 finally, the fasciculus uncinatus, which runs nearly vertical and which joins the 
 frontal to the sphenoidal lobe. 
 
104 
 
 DISEASES OF THE BRAIN. 
 
 notice particularly the inferior part, or the posterior cornu of 
 the ventricle which here plays an important role in topogra- 
 phy (Fig. 32). 
 
 Fibres of optic thalamus 
 extending to the periphery 
 
 Caudated nucleus 
 
 Fibres of caudated nucleus 
 extending to\ the- periphery 
 
 Direct 
 fibres. 
 
 
 
 FIG. 31. Scheme illustrative of the different orders of peduncular fibres. (Hugue- 
 nin.) 
 
 The caudated ganglion has been detached and its outlines 
 are represented by a dotted line ; its diverging fibres, that is 
 
CEREBRAL PORTION OF THE OPTIC NERVES. 10$ 
 
 to say, the plane of the cortico-striated radiating fibres, have 
 also been removed. Thus is uncovered the plane of the cor- 
 tico-optic radiating fibres. In these last fasciculi it is possible 
 to distinguish three groups of fibres : 1st, the anterior ones 
 called anterior roots of the thalami-optici (Vordere Stiel), they 
 are directed towards the frontal regions ; 2d, others are mid- 
 dle or lateral ; 3d, and finally, the posterior ones are desig- 
 nated by Gratiolet, who first 1 well studied them, under the 
 name of optic cerebral expansions, or expansion of the optic 
 nerves (Sehstrahlungen). The fasciculi of the last group, 
 which are the special object of our study, are separated from 
 the cavity of the posterior cornu only by the ependymus and 
 the tapetum, a special expansion of the splenium of the corpus 
 callosum. 
 
 It is in this same region, but on a deeper plane, that the 
 cerebral expansions of the fasciculi of centripetal fibres are 
 spread, the lesion of which produces sensitive hemianaesthe- 
 sia of cerebral origin. There exists, then, a relation of pro- 
 pinquity, of contiguity, between these fasciculi and the optic 
 expansions, and that relation would well explain anatomi- 
 cally the frequent coexistence of hemiansesthesia and crossed 
 amblyopia if it could be well established that those fasciculi 
 which bear the name of optic expansions are really a more or 
 less direct prolongation of the optic nerves. 
 
 II. We will make a little digression upon this point in 
 order to ascertain what is known about the gray ganglia at 
 the base of the encephalon, outside of the brain proper, where 
 the optic nerves originate. 
 
 Here it seems proper to examine the exterior architecture 
 of the parts which we are about to consider. 
 
 After detaching the entire isthmus from the encephalon, 
 leaving attached the thalami optici, an examination of the 
 posterior face of the preparation thus obtained will discover 
 as follows : 1st, anteriorly, on each side, are the thalami op- 
 tici, which separate the third ventricles ; 2d, posteriorly, the 
 
 1 See Gratiolet, Anat. comparee, t. II., p. 181 et suiv. Luys, loc. cit., p. 173. 
 
io6 
 
 DISEASES OF THE BRAIN. 
 
 tubercula quadrigemina, both anterior and posterior ; 3d, 
 externally, the anterior conjunctive fibres connecting by their 
 internal extremities with the anterior tubercula quadrigemina, 
 
 ^l(.TQOl Of 
 
 ^ Optic thaJamiis , 
 
 Corpus, 
 striatuiri 
 
 Arch, and 
 three pillars' 
 
 ions 
 
 Corpora"? 
 quadrigemma 
 
 Horn of Ammon' 
 JEbst-liom of la 
 
 -^ of 
 
 Gratiolet. (optic) 
 
 FIG. 32. Radiations from the thalamus opticus. (Huguenin.) 
 
 the posterior conjunctive fibres connecting with the posterior 
 tubercula quadrigemina. Then, in the same region, by raising 
 the posterior extremity of the thalami optici, or pulvinar, 
 may be seen, internally, the internal geniculate body, and ex- 
 
CEREBRAL PORTION OF THE OPTIC NERVES. IO/ 
 
 ternally, a gray mass, somewhat more voluminous, which is 
 the external geniculate body. 
 
 Behind and above these parts are to be seen the loop of 
 Reil, the processus cerebelli ad testes, the cerebral pedun- 
 cles, the restiform bodies, and the middle cerebral pedun- 
 cles. 
 
 The internal and external geniculate bodies are notably the 
 first two ganglia of gray substance with which the optic nerves 
 enter into rapport on their way to the encephalon. The optic 
 nerves posterior to the chiasma take the name of optic tracts, 
 or optic bands, and in the posterior two-thirds they are divided 
 into two tracts which may be considered as roots, the one 
 internal, the other external. 
 
 The external is most voluminous and also most important. 
 It furnishes several fibres which run to various gray ganglia. 
 1st. There can be seen a fasciculus which goes to the external 
 geniculate body. These bodies are a tolerably voluminous 
 mass of gray substance, enclosing ganglionic cells, stellate or 
 fusiform, of considerable dimensions, and which are to be 
 found well represented in the work of Henle (Fig. 177, p. 
 249). 2d. A second fasciculus, situated within the preceding, 
 enters the inferior portion of the thalamns about twelve milli- 
 metres anterior to the extremity of the pulvinar. Upon a 
 transverse section, such as is represented in the work of Mey- 
 nert (Fig. 249, II. R.), the fasciculus in question is situated 
 between the external geniculate body and the foot of the 
 peduncle. The existence of this fasciculus, affirmed by 
 Gratiolet, is also very explicitly recognized by Meynert, 
 Henle, and Huguenin. 3d. A third fasciculus which, accord- 
 ing to Gratiolet, should be the most apparent and best known 
 of the roots of the optic nerves, winds around the external 
 geniculate bodies and enters the anterior tuberculum quadri- 
 geminus of the corresponding side. 1 The description which 
 Gratiolet has given of this, confirmed also by Vulpian and 
 Huguenin, 2 is perfectly exact as concerns the most of mam- 
 
 1 Gratiolet, loc. cit., p. 180. 
 
 2 Huguenin, WestphalPs Arch., V. Bd., ist Heft, 2d Heft, 1875. 
 
108 DISEASES OF THE BRAIN. 
 
 mifera. 1 It does not hold true in the same degree for the 
 monkey; and in man, though the fasciculus exists, it can be 
 anatomically demonstrated only by great care. 2 
 
 It is thus seen that the external roots of the optic nerves 
 take their origin in three ganglia of gray substance, to wit : 
 1st, the thalami optici ; 2d, the external geniculate bodies ; 
 3d, the anterior tubercula quadrigemina (nates). Such cer- 
 tainly are the principal sources of the optic nerves in man, 
 and with a great number of animals they are probably the 
 only ones ; at least this seems to be established by the inter- 
 esting experiments of Gudden, 3 consisting of the extirpation 
 of the eyeballs of very young rabbits. In the animals thus 
 operated upon, when killed some months thereafter, it was 
 observed that consecutive atrophy had ensued in the central 
 parts upon the anterior tubercula quadrigemina (nates), the 
 thalami optici, and the external geniculate bodies ; on the 
 other hand, the posterior tubercula quadrigemina (testes) and 
 the internal geniculate bodies did not participate in the atrophy. 
 
 The internal roots, though less important than the external, 
 should not be neglected, especially when relating to man. 
 You know that they are connected with the internal geniculate 
 bodies. These internal geniculate bodies contain only rudi- 
 mentary nerve-cells (Henle), and consequently cannot be 
 considered as a centre in the same sense as can the external 
 geniculate bodies. The nerve-fasciculi of the internal root, it 
 may be either after traversing the geniculate bodies, or by a 
 direct course, proceed to a final termination at the anterior 
 tubercula quadrigemina (nates). 
 
 Quite recently Huguenin (Arch, fur Psychiatrie, 1875, V. 
 Bd., Fasc. .2, p. 344) has maintained that the internal roots of 
 
 1 For brains of the rabbit and dog, see plate, Gudden's work (Arch, of Ophthal., 
 XX., 1875) ; for brain of cat, the plates of Forel (Beitrage zur Kenntniss der 
 Thalamus Opticus). Sitzbericht. der k. Akad., LXVI. Bd., 1872, T. II., 
 Fig. 10. 
 
 8 A fourth fasciculus, situated outside of the one which stops in the external genic- 
 ulate body, is spread upon the thalamus and takes part in forming the Stratum 
 zonale. Previously indicated by Arnold and Gratiolet, this fasciculus is described 
 and represented also by Meynert, p. 436. 
 
 8 Gudden. Arch, fur Ophthalmol., XX. 
 
CEREBRAL PORTION OF THE OPTIC NERVES. 109 
 
 the optic nerves, in man at least, are in anatomical rapport 
 with the posterior tubercula quadrigemina, either directly 
 or by the intermediation of the internal geniculate bodies. 
 According to that, the posterior tubercula quadrigemina 
 could not, in man, be excluded, as it seems to be in animals, 
 from the apparatus of the optic nerves. This is not in con- 
 tradiction with the teaching of certain facts concerning gray 
 tabetic induration of the optic nerves. Quite recently, in an 
 ataxied woman blind for fifteen years gray induration of 
 the optic nerves could be followed beyond the chiasma along 
 the optic bands quite to the geniculate bodies. The tuber- 
 cula quadrigemina, the anterior (nates), as well as the pos- 
 terior (testes), had very nearly retained the white color of the 
 normal state, but they both were manifestly reduced in size 
 (case of Magdaliat 1 ). I have observed several cases, all sim- 
 ilar to the preceding. 
 
 We must now examine how the various masses of gray 
 substance which have been enumerated are brought into 
 relation with the gray cortex of the encephalon. The con- 
 nection is established, as I have shown, by a system of fibres 
 which constitute the most posterior portion of the radiations 
 of the thalami optici (cortico-optic diverging fasciculi), and 
 which are sometimes called the optic radiations of Gratiolet. 
 You can follow these somewhat complex anatomical details 
 in the following plate, which I borrow from the work of Mey- 
 nert, and which represents the brain of a monkey (Cercocebus 
 cinomolgus] (Fig. 33). 
 
 It can there be seen how the fasciculi of fibres, or radiations, 
 leaving the external geniculate bodies, the internal geniculate 
 bodies, the pulvinar, and the anterior tubercula quadrigem- 
 ina (these last by the intermediation of the anterior con- 
 junctive arms), go by a recurrent way to associate with a 
 medullary fasciculus which is only a collection of the direct 
 peduncular centripetal fibres that we have already described 
 (Lectures VIII. and IX., Fig. 26), and upon which the com- 
 mon sensibility of the opposite side of the body depends. 
 
 1 The anterior and posterior conjunctive arms were remarkably atrophied ; they 
 had a heavy white color, a little tinted with yellow. 
 
no 
 
 DISEASES OF THE BRAIN. 
 
 With that collection of fibres are doubtless mingled other 
 fibres coming from the olfactive tract by way of the anterior 
 commissure, the extremities of which, according to the de- 
 scriptions of Burdach and Gratiolet, are directed posteriorly 
 
 Denial extremity. 
 
 Ertfrance of 
 fiss.of Srlvius. 
 
 Segments' of 
 lentic. nucleus. 
 
 'orpus callosutn. 
 
 ueue of caudated 
 "nucleus , 
 
 Ant. horn o 
 lat. ventricle, 
 
 Septum lucid _ . 
 .Crus cerebri. (foot) 
 Ant .commissure. 
 
 ddle ventricle, 
 ddle commissure^ 
 
 .ddle ventricle. 
 
 Optic thalamus^ 
 '.to corp, genie. 
 
 rpus callosum. 
 
 Corpora 
 
 JM&\ 
 
 Corpora quadr. extern. 
 Corpora quadrigemina 
 
 Horn of/ 
 
 Post.iiom.ofLatVent. 
 tic thalamug. 
 
 Occipital region, 
 
 FIG. 33. Antero-posterior horizontal section of the left hemisphere of a monkey's 
 brain ((Jercocebus cino molgus}. (Meynert, Strieker's Handbook.) 
 
 into the substance of the occipital and sphenoidal lobes. 
 Clinical facts lead to the belief that there also are mingled 
 decussating nerve-fibres connected with the auditory and 
 gustatory nerves. If that arrangement, now altogether hy- 
 pothetical, should come to be anatomically verified, it can 
 
CEREBRAL PORTION OF THE OPTIC NERVES. Ill 
 
 be understood how crossed obscuration of the smell, taste, 
 and hearing should, in the same manner as amblyopia, be an 
 ordinary symptom of cerebral hemiancssthesia^ 
 
 The encephalic region to which I have drawn your atten- 
 tion, and which responds to the most posterior part of the 
 foot of the radiating fibres (couronne rayonnante), may be 
 considered, then, as a highway where, in the depths of the en- 
 cephalon, are encountered, within a very narrow space, all the 
 sensitive and sensorial lines of travel. This is a highway ; 
 it is not a centre. The cerebral centre, properly speaking, 
 should be sought in the prolongations of the medullary fibres, 
 in the gray cortex of the occipital and sphenoidal lobes. 
 
 We shall return to this point in connection with localiza- 
 tions in the cortical system. 
 
 III. You might have observed in the preceding anatomical 
 expose that the tubercula quadrigemina seem to furnish the 
 only point where the fasciculi of the optic nerves, after their 
 decussation in the chiasma, again approach each other upon 
 the median line. This is the point where that supplementary 
 decussation is effected, which, according to my hypothesis, 
 would reduce the optic nerve to the same footing as other 
 nerves. That is a question which at present seems difficult 
 to resolve by exclusively anatomical means. Upon the 
 median line, between the tubercula quadrigemina, numerous 
 decussations of fibres are without doubt anatomically demon- 
 strated. But it cannot be decided whether these decussated 
 fibres are really in connection with the optic nerves, and es- 
 pecially whether they are the prolongations of optic fibres 
 non-decussating in the chiasma. Experimentation, and above 
 all pathological anatomy, should certainly have the first place 
 in the solution of this question. The experiments of Flou- 
 rens have already shown that with mammifera and with birds, 
 the ablation of the optic tubercles produce amblyopia or 
 crossed amaurosis. But this is with animals in which the 
 
 1 According to the theory, cerebral hemiansesthesias should be distinguished 
 from those dependent upon a lesion of the protuberance or the cerebral peduncles 
 (crus cerebri) by non-participation in the last case of vision or smell. 
 
112 DISEASES OF THE BRAIN. 
 
 ocular axes are directed externally and in which the decus- 
 sation in the chiasma is doubtless complete. 
 
 With man the elements for the solution of the problem are 
 as yet defective. With him lesions of the tubercula quadri- 
 gemina are not rare, but they ordinarily are bilateral, and 
 consequently producing bilateral blindness, they can prove 
 nothing. In fact, it is still a question whether lesions of the 
 anterior tubercula quadrigemina will, like a lesion of the optic 
 bands, produce lateral hemiopia, or if, on the contrary, they 
 will produce crossed amblyopia, as would be in keeping with 
 my hypothesis. In favor of my hypothesis, I can as yet cite 
 but one case, reported by Dr. Bastian, and in which a unilat- 
 eral lesion of the anterior tubercula quadrigemina had pro- 
 duced crossed amblyopia. 
 
 But that fact is at present the only one, and besides it is 
 related with too little detail to be received as decisive. 1 
 
 IV. It remains to ascertain if crossed amblyopia is the 
 only kind of functional trouble of the vision which can be 
 produced by a lesion of the brain proper, or if, on the con- 
 trary, hemiopia may not also follow as a consequence of cer- 
 tain pathological localizations in the hemisphere. That is a 
 point which, I think, no one is at present competent to de- 
 cide. I incline, however, in the absence of contradictory 
 autopsies, to believe that in most instances of hemiopia 
 which have been ascribed to a lesion of the brain, the lesion 
 has either not occupied the deep regions of the hemisphere, 
 or that it has extended to the basilar portions in such manner 
 as to involve more or less directly one or the other of the 
 optic bands. 
 
 To show that deep lesions of the brain produce hemiopia 
 lateral hemiopia cases are specially cited where the visual 
 disturbance is suddenly developed upon an apoplectic stroke, 
 and where, at the same time, the limbs of one side are affected 
 with motor hemiplegia, and sometimes also with anaesthesia. 
 Nothing is better established in clinic than facts of this kind, 
 
 1 H. C. Bastian, The Lancet, 1874, 25th July. 
 
CEREBRAL PORTION OF THE OPTIC NERVES. 113 
 
 of which Schoen, quite recently, in an interesting work, has 
 cited several examples. 1 But the conduction of the autopsies 
 have to the present been faulty, and it may be queried if the 
 lesion found in these cases occupied really the deep brain, or, 
 on the contrary, the base of the encephalon. It seems estab- 
 lished, you have not forgotten, that destruction or compres- 
 sion of one of the optic bands produces lateral hemiopia ; and, 
 on the other hand, the anatomical relation which exists be- 
 tween the bands and certain parts of the isthmus, such, 
 among others, as the crura cerebri, is well known. Such 
 being the case, it could not be otherwise than that a lesion 
 properly localized, as, for example, in a crus cerebri, might 
 result in producing at the same time lateral hemiopia and 
 motor hemiplegia, and perhaps also hemianaesthesia. Hem- 
 orrhage, suddenly developed in the substance of the pos- 
 terior part of the thalami optici, might, as can be understood, 
 be followed with the same effect. It is evident that these 
 diverse combinations are only phenomena of propinquity. 
 
 In any case, it should be known that among instances 
 which have been reported of lateral hemiopia of supposed 
 intracerebral origin, there are a certain number which in some 
 respects do not conform to the interpretations that I have 
 proposed. Such, among others, are those where right lateral 
 hemiopia develops itself in concert with aphasia, and some- 
 times also with various modifications of the sensibility or 
 motion of the limbs of the right side of the body. 2 
 
 These facts do not constitute a homogeneous group ; the 
 first category includes a form peculiar to migraine , 3 that is, 
 symptoms essentially transitory, returning by accesses, and 
 above all marked by scintillations, vertigo, more or less 
 marked lateral hemiopia, and sometimes also with a certain 
 
 1 Arch, der Heilkunde, p. 19, 1875. 
 
 2 Various cases of this kind have recently been related by Bernhardt (Berliner 
 klin. Wochen., 32, 1872, and Centralblatt, 1872, 39), and by Schoen (loc. cit.). 
 See also H. Jackson, A Case of Hemiopia with Hemianaesthesia and Hemiplegia, 
 in the Lancet, Aug. 29, 1874, p. 306. 
 
 3 See respecting this form of migraine the works of Tissot, Labarraque, Piorry, 
 and Latham (on Nervous Sick Headache, Cambridge, 1873), and above all the re- 
 cent work of Ed. Liveing (on Megrim, etc., London, 1873). 
 
 8 
 
114 DISEASES OF THE BRAIN. 
 
 degree of aphasia and numbness in the face and limbs of the 
 right side. Headache, nausea, and vomiting usually end the 
 attack. It is clear that these cases cannot be ascribed to a 
 durable, material alteration. It is not thus with the cases of 
 the second category, where the concurrence of aphasia, hemi- 
 plegia, and hemiopia- remain permanent. 1 
 
 At present I do not see how these various cases, revealed 
 by clinic, can be anatomically explained upon the hypothesis 
 of a single lesion. I can only call attention to the difficulties, 
 the solution of which is reserved to the future. 
 
 1 It can be understood that a voluminous tumor might produce all the results 
 noted in both categories, and it has happened in a case recently published by 
 Hirschberg in the Archives of Virchow (Virchow's Arch., T. 65, I Heft, p. 116). 
 This patient had, besides very characteristic right lateral hemiopia, aphasia, and 
 hemiplegia of the right limbs. Upon autopsy there was found in the substance of 
 the left frontal lobe, a tumor the size of an apple, of the kind called vascular 
 glioma. The optic tract of the left side was very flattened. The views enter- 
 tained in the present chapter find a confirmation in that fact, since the hemiopia 
 there noted may belong to compression of the optic tract, 
 
TWELFTH LECTURE. 
 
 SECONDARY DEGENERATION. 
 
 Summary : Anterior or Lenticulo-Striatcd Region of the Central Masses 
 (Anterior Two-thirds of Internal Capsule, the Caudated and 
 Lenticular Ganglia). Influence of Lesions in these Regions upon 
 the Production of Motor Hemiplegia. Experimental Facts. Accord 
 "between these and the Facts of Human Pathology. Difference 
 between the Lesions of the Caudated Ganglion and those of the 
 Anterior Part of the Internal Capsule Secondary Degenerations, 
 or Descending Scleroses. Lesions which Produce them; Impor- 
 tance of the Locality and Extent of these Lesions. Characteristics 
 of Descending Scleroses ; Extent; Appearance of the Lesion upon the 
 Crus Cerebri, the Protuberance, the Anterior Pyramid, and the Lat- 
 eral Fasciculus of the Spinal Cord. Analogies and Differences be- 
 tween Lateral Sclerosis from Cerebral Cause, and Primitive Fascicu- 
 lated Sclerosis of the Lateral Fasciculi. Symptoms Belonging to Sec- 
 ondary Sclerosis ; Motor Impotency, Permanent Contractions. Mus- 
 cular Atrophy Produced by Extension of the Lateral Sclerosis to the 
 Cornua of the Gray Substance. Descending Sclerosis Following 
 a Lesion of the Cortex. Demonstration of the Direct Peduncular 
 Fibres ; Anatomico-Pathological Facts. The Locations of Cortical 
 Lesions which Produce Secondary Degenerations Correspond to 
 the Locations of Centres called Psycho.Motor. 
 
 GENTLEMEN : 
 
 We must again turn to the anterior regions of the central 
 masses, for the purpose of studying more carefully the ana- 
 tomical and pathologico-physiological effects of lesions occur- 
 ring in that locality. 
 
 That region, which may be called the lenticulo-striated, in 
 contradistinction to the posterior or lenticulo- optic region, 
 embraces, you remember, 1st, the anterior two-thirds of the 
 white tract called the internal capsule ; 2d, internally from 
 this, the large extremity or head of the caudated ganglion ; 
 3d, outside, by the side of the island of Reil, the anterior two- 
 thirds nearly of the lenticulate ganglion. 
 
DISEASES OF THE BRAIN. 
 
 Observation, and that many times repeated, demonstrates 
 as I have already remarked in the course of these lectures 
 Lectures VIII. and IX., pp. 70 and 71), that common motor 
 hemiplegia, unaccompanied by derangement of sensibility, is 
 the almost inevitable consequence of even the smallest lesions 
 occurring in the various parts which I have enumerated, 
 provided always that the lesions in question produce the de- 
 
 Corpus/^ r ** 
 callosum-iv^-" ' ^ 
 
 Chalamus 
 
 FIG. 34. An old softening of the middle portion of the caudated ganglion and the 
 internal capsule. (Right side.) 
 
 struction or the sudden compression of the nerve -elements of 
 the affected area, instead of merely a slowly effected dis- 
 placement, as is often seen in the case of tumors. 
 
 I called attention to an important distinction which should 
 be established. This is, that lesions, even extensive and 
 deep, which remain limited to the gray ganglia (caudated 
 and lenticular ganglia), produce, as a general rule, symptoms 
 relatively slight and transient, while lesions comparatively 
 
SECONDARY DEGENERATION. 1 1/ 
 
 slight, which involve the white tract (internal capsule), give 
 rise to a motor hemiplegia, not only very decided, but also 
 of long duration and often incurable (Fig. 34). 
 
 Let us try and ascertain the reason of these differences. 
 First, concerning the intensity of the paralytic symptoms in 
 cases of lesions of the internal capsule compared to that mild 
 degree in cases of lesions limited to the gray ganglia ; then 
 we will examine the transitory character of hemiplegia in the 
 last kind of cases as contrasted with the permanence of the 
 same symptom which almost invariably results from lesions 
 of the internal capsule. 
 
 I. Concerning the first point, I will remind you again of 
 the anatomical construction of the internal capsule. That 
 tract embraces : 1st. The direct peduncular fibres that is, 
 those originating beneath the gray cortex, and which enter 
 the inferior portion of the crura cerebri without having entered 
 into relation with the lenticular or caudated gray ganglia. 
 2d. The indirect peduncular fibres, which, on the contrary, 
 originate in the lenticular or caudated ganglia, and have no 
 connection with the gray cortex. For the moment we will 
 leave unnoticed those fasciculi of fibres which extend from the 
 cortical substance to the gray ganglia of the central mass. 
 
 We will suppose that the various peduncular fibres, direct 
 and indirect, are centrifugal, and that they transmit to the 
 periphery the motor influence developed, it may be, in the 
 gray cortex of the brain, or in the lenticular and caudated 
 gray ganglia. 
 
 With this hypothesis it is easy to comprehend that a small 
 lesion of the internal capsule, especially near its inferior part, 
 in the vicinity of the foot of the cerebral peduncle, where all 
 the fibres are reassembled in a narrow space, would, at one 
 blow, suppress the influence of the gray cortex and that of 
 the two gray ganglia ; while, on the contrary, a lesion limited 
 to the lenticular ganglion would leave free the action of the 
 caudated ganglion and that of the gray cortex. The effects 
 of various combinations of this sort which might happen can 
 easily be imagined ; lesion of the caudated ganglion, of cer- 
 
Il8 DISEASES OF THE BRAIN. 
 
 tain regions of the gray cortex, of the two gray ganglia, with 
 or without the participation of the peduncular fibres of the 
 internal capsule, etc. 
 
 I attach no more importance to this theoretical view than 
 is permissible. It adapts itself well to the facts obtained by 
 clinical observation upon man, and I will add also that it is 
 in no part contradicted (you may judge for yourselves) by 
 experiments made with animals. 
 
 For a long time it has been known l that with the majority 
 of animals motor disturbances produced by the methodic de- 
 struction of various parts of the encephalon, particularly of 
 the brain, differ considerably in a general way from similar 
 pathological lesions of corresponding parts in man. 
 
 In the interpretation of these experimental facts, and in 
 their application to human pathology, there should be taken 
 into account, among other things, the greater or less inferior- 
 ity of the species of animals and the more or less advanced 
 age. Thus, the entire ablation of a cerebral hemisphere of a 
 pigeon (and still more marked, of course, with a reptile) 
 would produce no trouble which could be compared to hemi- 
 plegia. It is nearly the same with the rabbit. A feebleness 
 slightly noticeable in the limbs of one side of the body is the 
 only consequence of such a lesion in the rabbit. Standing 
 and jumping are still possible, even though the entire brain 
 has been destroyed, provided always that the protuberance 
 remains intact. 2 With the dog, the results become notably 
 different. From the last experiments made in the laboratory 
 of Vulpian, by Carville and Duret, the results of methodic 
 ablation of the various parts of the dog's brain greatly resem- 
 ble those observed in cases of corresponding lesions of the 
 cerebral hemisphere in man. 
 
 If the experiments were made upon the monkey, it is prob- 
 able that the resemblance would be still more manifest and 
 complete. 
 
 Here is a brief expose of the principal results obtained by 
 
 1 See upon this subject Longet. Trait e de physiologic, t._III., p. 431, and 
 Vulpian. Le9ons sur la physiologic generate, etc., p. 676. 
 
 2 Vulpian, Longet. 
 
SECONDARY DEGENERATION. 
 
 119 
 
 lenticular 
 Section of ant. portion^ j 
 of internal capsule j 
 
 Caudatedniidjei 
 *, of .corpora 'strata. 
 
 t 
 
 the experiments of Carville and Duret : 1st. In the dog, ab- 
 lation of the gray substance of the central cortex of those 
 regions called motor centres produced a temporary weakness 
 (paresis) of the limbs upon 
 the opposite side. 2d. The 
 extirpation of the caudated 
 ganglion produced an anal- 
 ogous but more marked 
 paresis. Nothing can at 
 present be said of the len- 
 ticular ganglion, the ablation 
 of which, owing to its topo- 
 graphical position, could not 
 be effected ; l 3d. If, on the 
 contrary, the lesion be made 
 upon the inferior part of the 
 internal capsule, it produces 
 in both fore and hind limbs 
 of the opposite side, not 
 only a simple paresis, but 
 a well-marked motor paraly- 
 sis which resembles the hemiplegia in man resulting from le- 
 sions of the same parts (Fig. 35). Held suspended by the 
 skin of the back, the animal thus operated on could still stand 
 on the sound limbs, but the affected ones hung flaccid, inert^ 
 and no longer capable of any movement except that which was 
 purely reflex. 
 
 In short, you see from these interesting researches, which 
 are worthy of multiplication, that the contradiction long since 
 noticed between animals and man, relative to the influence of 
 various parts of the hemisphere of the brain upon movement of 
 the opposite limbs that contradiction, I say, seems no longer 
 to exist when the specimen for the comparison is relatively high 
 in the animal scale. (Fig. 36.) 
 
 Perhaps it is not here out of the way to recall that even in 
 
 1 In this respect it is difficult to utilize the experiments of Nothnagel with caus- 
 tic injections. These injections must almost necessarily produce phenomena of 
 excitation, which assuredly introduce a complication. 
 
 InLcapsule, 1 /'' j \ !Int. capsule, 
 Chiasma of optic nerves * 
 
 FIG. 35. Transverse section of adog' 3 
 brain, five millimetres anterior to the opti 
 chiasma. (Operation, of Veyssttre.} 
 
I2O 
 
 DISEASES OF THE BRAIN. 
 
 the dog the result of experiments by both Carville and 
 Duret and Veyssiere lesions of the posterior part of the inter- 
 nal capsule produced crossed hemianaesthesia the same as 
 with man. 
 
 II. I think the previous considerations may render plain 
 the reason why hemiplegias resulting from destructive lesions 
 
 Caudat^d nuclei 
 
 InV. capsule, ppstportion. 
 
 HornsV--'-" 
 of-Ammon. 
 
 FIG. 36. Transverse section of a dog's brain on a plane with the tubercula mammil- 
 laria. (Carville and Duret. ) 
 
 confined to the substance of the gray ganglia are as a rule 
 temporary, while those resulting from lesions in the substance 
 of the internal capsule are, on the contrary, of longer dura- 
 tion, and often even absolutely incurable. 
 
 Through the hypothesis proposed, it can easily be under- 
 stood how the lenticular and caudated ganglia and the regions 
 called the motor centres in the gray cortex of the hemispheres 
 could mutually supplement each other in their functions, so 
 long as the conducting fasciculi which form the capsule have 
 preserved their integrity, and could continue to maintain the 
 relations of any one of the gray centres in question with the 
 peripheric parts ; whereas this could not take place if the 
 continuity of these fasciculi had been decidedly interrupted. 
 
 I will add that in all probability this supplementing may be 
 established not only between the various gray ganglia, but 
 also between the various parts of the same ganglion. It is 
 
SECONDARY DEGENERATION. 121 
 
 demonstrated, at least as concerns the caudated ganglion of 
 the corpus striatum, that partially destructive lesions affecting 
 the most diverse regions of the ganglion are uniformly ex- 
 pressed by a more or less marked and transitory, but total 
 hemiplegia ; that is, affecting at the same time both the face 
 and the limbs. In this respect there can be distinguished no 
 difference between the head, the tail, or the middle part of 
 the caudated ganglion. It would thus seem that H. Jackson 
 was correct in remarking that each parcel of the striated body 
 represented in miniature the entire body. Moreover, experi- 
 mentation gives results in conformity with those furnished by 
 clinical observation, in showing that partial excitation of the 
 caudated ganglion, however effected, always produces move- 
 ments of the entire opposite side of the body, and never dis- 
 associated movements ; localized, for example, in one limb, or 
 in a portion of a limb. 1 
 
 In case of a destructive lesion of the internal capsule, a 
 slow regeneration of the nerve-elements may, on the contrary, 
 permit the gradual re-establishment of the functions. Now, 
 that labor of restitution, if it is really sometimes accomplished, 
 most certainly is not always so ; it occurs only as an excep- 
 tion. It is placed beyond doubt, indeed, by very numerous 
 observations, that those lesions which to a certain extent de- 
 stroy the motor fibres of the internal capsule, have, as an 
 almost necessary consequence, the production of a fascicular 
 lesion which, commencing immediately below the site of the 
 lesion, can be traced in the corresponding side to the foot of 
 the peduncle, along the protuberance, and the anterior pyr- 
 amid to the level of the bulbular decussation, and beneath 
 this into the spinal cord, on the side opposite to that of the 
 lesion, through the entire length of the lateral fasciculus down 
 to the lumbar enlargement. 
 
 III. I think some explanations concerning the anatomy 
 and pathological physiology of secondary degenerative or de- 
 scending scleroses, as they still may be called, will not here 
 
 1 Experiences of Ferrier, Carville and Duret. 
 
122 DISEASES OF THE BRAIN. 
 
 be amiss. They are incontestably one of the principal causes 
 of the persistence of motor impotency in the cases under con- 
 sideration. In my opinion, we must also join to them the 
 major part of permanent contractions, called late contractions 
 (tardive^ which in these cases sooner or later take possession 
 of the paralyzed limbs, and in a general way play a predom- 
 inant role in the prognosis of cerebral hemorrhage. 
 
 1st. Let us first pause in face of a fact which really rules 
 the question : cerebral lesions (en foyer), considered as re- 
 spects their location, are not all equally able to produce con- 
 secutive sclerosis. 
 
 Thus, among these lesions, some are never followed by 
 descending sclerosis, while others almost surely are. To this 
 last kind belong destructive lesions, however slight, which, 
 according to the important observation of L. Turck, involve 
 the fasciculi of the internal capsule in their course between the 
 lenticular and caudated ganglia, that is, along the anterior 
 two-thirds of the capsule. On the contrary, those lesions con- 
 fined to the substance of the gray cerebral masses, namely, 
 the lenticulated and caudated ganglia and the thalami optici, 
 produce no consecutive sclerosis. 
 
 That remarkable fact was thoroughly brought to light by 
 L. Tiirck 2 in 1851. Vulpian and I have both recognized 
 its entire exactitude in -the researches which we have made 
 together at Salpetriere from 1861 to i866. 3 The important 
 works of Bouchard have equally confirmed it. 4 There are also 
 a certain number of other facts, furnished by L. Tiirck, not less 
 interesting, and of which the following is the gist : 
 
 1 We are indebted, as is known, to Dr. Todd for having established a distinc- 
 tion between early and late (precoce et tar dive) contraction in the limbs of an 
 apoplectic. The first appears at the commencement and is nearly always transitory ; 
 the other does not appear before the fourteenth to the thirtieth day after the attack, 
 is situated always in the limbs of the side opposite to the lesion, and in the 
 majority of cases is permanent. 
 
 3 L. /Tiirck. Ueber secundare Erkrankung einzelner Riickenmarkstrange und 
 ihrer Forsetzungen zum Gehirne. Sitzungsber. der mathnatur. Classe d. K. Ak., 
 1851. Idem., XI. Bd., 1853. 
 
 s A. Vulpian. Physiologic du systeme nerveux, Paris, 1866. 
 
 4 Ch. Bouchard. Des degenerations secondaires de la molle epiniere. In Arch, 
 gen. de medecine, 1866. 
 
SECONDARY DEGENERATION. 
 
 123 
 
 2<d. Lesions situated outside of the central masses, in the 
 centrum ovale of Vieussens, produce descending sclerosis, 
 provided they are not too far removed from the foot of the 
 radiating fibres (couronne rayonnante). 
 
 3d. Lesions of the gray cortical substance of the hemi- 
 spheres, when they are very superficial, such, for example, as 
 those which habitually accompany meningitis, do not produce 
 descending sclerosis. 
 
 'Center of 
 Softening: 
 
 FIG. 37. Cortical ischaemic softening without involving the central masses. 
 
 4th. On the contrary, cortical lesions which are both 
 extended and profound, that is, involving both the gray sub- 
 stance and the subjacent medullary substance, as seen in 
 cases of ischaemic softening resulting, for example, from the 
 obliteration of a voluminous branch of the Sylvian artery 
 (see Fig. 37) these lesions, I say, even when there is no par- 
 ticipation of the central masses, produce in certain cases con- 
 secutive sclerosis as marked as that which depends upon a 
 lesion of the anterior region of the internal capsule. 
 
 Among these conditions there is one especially relating to 
 the location of cortical lesions, which should be made partic- 
 ularly clear. We have observed that superficial softenings 
 (yellow patches) occupying either the occipital lobe, the pos- 
 
124 
 
 DISEASES OF THE BRAIN. 
 
 terior parts of the temporal or sphenoidal lobe, or the ante- 
 rior regions of the frontal lobe, are not succeeded by consec- 
 utive fascicular sclerosis, while on the other hand these scle- 
 roses, as a rule, follow lesions of the two ascending convolu- 
 tions (ascending parietal and ascending frontal), and the con- 
 tiguous parts of the parietal and frontal lobes (Fig. 38). Fur- 
 ther on I will return more especially to this point, which I 
 now merely mention. 
 
 FIG. 38. Human brain, left side ; destruction of the ascending parietal convolu- 
 tion and a great part of the ascending frontal convolution. 
 
 5th. In brief, the locality and extent of the lesion seem 
 here to be the two fundamental conditions ; the nature of the 
 lesion seems to have no marked influence. The required 
 locality and extent being given, descending sclerosis should 
 follow, provided the lesion is a destructive one, that is, one 
 capable of interrupting the course of the medullary fibres. 
 Centres of hemorrhage or softening, and simple or syphilitic 
 encephalitis, have in this respect much the same rank. It is 
 not the same with certain tumors which, through a long period 
 of evolution, only crowd back or to one side the medul- 
 lary elements without interrupting their continuity. This is 
 the reason why they may exist, even in the regions above 
 specified, unaccompanied by consecutive fascicular scle- 
 rosis. 
 
SECONDARY DEGENERATION. 125 
 
 IV. As for the anatomy of fascicular sclerosis, I refer for 
 details to the important memoire published by Bouchard. I 
 will only remind you of some facts to which our present stud- 
 ies give a particular interest. 
 
 1st. I will commence by recalling that sclerosis following a 
 lesion (en foyer) in the cerebral hemispheres always occupies 
 one-half of the lateral fasciculi. It is more or less marked and 
 more or less extensive according to the size of the fasciculus ; 
 but always extends down to the inferior end of the lumbar en- 
 largement, never stops by the way. They are always descend- 
 ing, in the sense that, taking origin on a level with the point 
 of lesion, they never extend except below that point ; they 
 are never found above it, towards the gray cortex. The 
 atrophy of one or several of the convolutions, or even of the 
 entire hemisphere, such as is seen when a central lesion (en 
 foyer) is developed in very young subjects, is not necessarily 
 the result of a sclerosis. That arises from an arrest of de- 
 velopment which may be compared to atrophy, which, under 
 like circumstances, is to be seen in the limbs upon the side 
 of the body affected by hemiplegia (infantile spasmodic hemi- 
 plegia). 
 
 2d. Microscopic examination alone, in cases which have 
 existed for some time and are rather marked, can recognize 
 some of the most prominent characters of the alteration. Let 
 us suppose a yellow patch, interrupting in the left hemisphere 
 the course of the fibres of the internal capsule in its middle 
 third. In such a case the foot of the crus cerebri of the left 
 side will appear flatter and narrower than that of the opposite 
 side. There will also be seen a grayish band situated upon 
 the middle part of the peduncle, 1 which upon an antero-pos- 
 terior section does not extend beyond the gray layer of Soem- 
 mering. The gray color disappears at the level of the protu- 
 berance ; it is found again below, in the bulb, where it occu- 
 pies the entire extent of the anterior pyramid on the side 
 corresponding to the cerebral lesion ; the affected pyramid is 
 
 1 The situation occupied by that band varies according to the location of the 
 central lesion ; it is nearer the internal border of the foot of the peduncle in pro- 
 portion as the lesion of the capsule is situated anteriorly. 
 
126 DISEASES OF THE BRAIN. 
 
 narrowed and flattened ; lower down, the teeth of the bulbu- 
 lar decussation show more distinctly than in the normal con- 
 dition by reason of the contrast which exists between the 
 sound and diseased sides. Below the decussation it is in the 
 opposite side of the spinal cord (opposite to the affected 
 hemisphere), in the lateral fasciculus, that the sclerosis should 
 be sought for ; the alteration is in the form of a triangular 
 space, of gray color, situated immediately external and ante- 
 rior to the corresponding posterior gray cornu, the area of 
 which lessens in proportion as the sections are made lower 
 down on the cord. 
 
 3d. Microscopic studies, made upon sections properly hard- 
 ened and prepared, greatly contribute to our knowledge. 
 In the first place, they furnish the means for locating more 
 exactly the topography of the lesion, and to make known, in 
 the spinal cord, for example, the precise limitation of the area 
 in the lateral fasciculus. The other white fasciculi and the gray 
 cornua remain entirely unchanged. It is to be noticed, at the 
 same time, that the roots of the nerves, anterior and poste- 
 rior, as well as the meninges, exhibit no trace of alteration. 
 
 Lastly, the microscope makes known also the nature of the 
 morbid process, and furnishes proof of a gray induration a 
 sclerosis which differs in no essential particular from that 
 observed in cases of primitive fascicular sclerosis. 1 
 
 4th. Here is the place to call attention to the analogies 
 which exist in an anatomico-pathological point of view be- 
 tween consecutive fascicular sclerosis, of cerebral origin, and 
 those primitive and symmetrical fascicular scleroses of the lat- 
 eral fasciculi which I last year described in connection with 
 spinal muscular atrophy (amyotrophies spinales}. 
 
 These analogies are considerable, since the same alteration 
 (gray induration) is in both cases located in the same tissue. 
 But there are also variations worthy of notice ; thus, in prim- 
 itive sclerosis the fascicular lesions are necessarily double, that 
 
 1 Those cases where the extension of the lesion exceeds its habitual limits, the 
 invasion, for example, of the anterior gray cornua, which will be considered farther 
 on, are certainly among the most decisive arguments which can be employed to 
 establish the irritative nature of the morbid process. 
 
SECONDARY DEGENERATION. 
 
 127 
 
 is, they occupy the lateral fasciculi of both sides simulta- 
 neously, instead of one side only, as is always the case in con- 
 secutive sclerosis, when the lesion from which it arises is uni- 
 lateral. I will also add that it is very much less extended 
 transversely, and there is reason to believe, therefore, that 
 beyond the cerebro-spinal or pyramidal fibres, which are the 
 only ones affected in consecutive sclerosis, primitive sclero- 
 
 FIG. 40. 
 
 FIG. 39. 
 
 FIG. 39. Transverse section of the spinal cord in a case of consecutive lateral fas- 
 cicular sclerosis ; from softening of the optico-striated bodies and the internal capsule. 
 (Cervical region.) 
 
 FIG. 40. Transverse section of the spinal cord in a case of consecutive lateral 
 fascicular sclerosis. (Dorsal region.) 
 
 sis invades also the spinal fibres of the lateral fasciculus (com- 
 pare Figs. 39, 40, and 41, and Figs. 42, 43, and 44). 
 
 FIG. 41. 
 
 FIG. 42. 
 
 FIG. 41. Transverse section of the spinal cord in a case of consecutive lateral 
 fascicular sclerosis. (Lumbar region.) 
 
 FIG. 42. Transverse section of the spinal cord in a case of primitive lateral 
 fascicular sclerosis. (Middle portion of cervical enlargement.) 
 
 Finally, primitive sclerosis has a great tendency to extend 
 to the neighboring spinal regions, to the white fasciculi, and 
 
128 
 
 DISEASES OF THE BRAIN. 
 
 especially the anterior cornua of the gray substance, which 
 is not the rule in the consecutive form. 1 
 
 FIG. 43. 
 
 FIG. 44- 
 
 FIG. 43. Transverse section of the spinal cord in a case of primitive lateral fas- 
 cicular sclerosis. (Middle of dorsal region. ) 
 
 FIG. 44- Transverse section of the spinal cord in a case of primitive lateral 
 fascicular sclerosis. (Middle of lumbar enlargement.) 
 
 1 Here are some more precise details relative to the anatomical differences 
 existing between consecutive lateral sclerosis and primitive lateral sclerosis, amyo- 
 trophic. They are examinations made upon hardened transverse sections, where, 
 even in the bulb, secondary sclerosis has involved nearly all the fibres of the ante- 
 rior pyramid, and in the spinal cord the lesion occupies only a comparatively nar- 
 row space in the lateral fasciculus. Upon a transverse section made at the cervi- 
 cal enlargement, the lesion is seen as a triangle with very clearly defined borders, 
 the apex of which is directed inward toward the angle which separates the ante- 
 rior from the posterior gray cornua, the base a little rounded, does not extend to 
 the circumference of the cord, neither does it involve the antero-external border of 
 the posterior cornu (Fig. 39). In the dorsal region the sclerotic portion pro- 
 gressively diminishes in diameter and tends to resume an oval form (Fig. 40). 
 Finally, in the lumbar enlargement (Fig. 41), it resumes as in the cervical region, a 
 sort of triangle, but in this locality the base of the triangle is quite superficial, next 
 to the pia mater. 
 
 In primitive lateral sclerosis, the sclerotic zone occupies in a general way the 
 same region as does consecutive sclerosis, but its area is much greater. Thus, 
 anteriorly, the lesion tends to invade the anterior radiating zones, and internally 
 it extends so as to come in contact with the nerve-fibres (perhaps sensitive) which 
 constitute the profound part of the lateral fasciculi (see Figs. 42, 43, 44). It must 
 be added that here the borders of the lesions become ill-defined. In some cases 
 they seem to be confounded with the gray substance. It is known that the gray 
 substance is regularly invaded by sclerotic alterations in cases of lateral amyotro- 
 phic sclerosis, whereas it is very exceptional in consecutive sclerosis from cerebral 
 cause. 
 
 From the preceding considerations there is reason to think that consecutive 
 sclerosis affects only one part of the nerve-fibres which compose the lateral fas- 
 ciculi, namely, the cerebro-spinal fibres ; whereas, in primitive sclerosis, it invades 
 
SECONDARY DEGENERATION. 129 
 
 There is, however, a chapter of exceptions which in this 
 connection is particularly interesting. 
 
 IV. The facts gathered in the course of the preceding 
 expose enable us to justify the proposition with which this 
 chapter commenced. We have established in an anatomical 
 point of view that there exists a very considerable analogy 
 between primitive and consecutive forms of lateral fascicular 
 sclerosis. That assimilation can be followed upon the clini- 
 cal field. It is known, indeed, that motor loss, contraction of 
 the limbs, at first transient, then permanent, with sponta- 
 neous or provoked trepidation, etc., provide a symptomatic 
 group which reveals during life the existence of primitive 
 fascicular spinal sclerosis, that is, independent of any cerebral 
 lesion. Now all the essential characters of these symptoms 
 are reproduced in sclerosis arising from a lesion in the brain, 
 the clinical picture, in fact, of common permanent hemiplegia. 
 It may be said, then, that there exists a relation between the 
 phenomenon of " permanent contraction " and " lateral sclero- 
 sis," the physiological reason of which at present completely 
 eludes us, but the reality of which is nevertheless established 
 by a great number of observations. 1 
 
 In my opinion, it is not the retraction of the cerebral cica- 
 trix, as Todd would hold, nor yet encephalitis supervening 
 from proximity to the lesion, as very many authors at present 
 maintain, which can explain the apparition of those contrac- 
 tions in hemiplegias called tardy (tardive) ; on the contrary, 
 it is more reasonable to attribute it to a chronic myelitis in 
 the lateral fasciculus resulting from the cerebral lesion. I will 
 avoid discussion, and once more refer you to the work already 
 cited of Bouchard, in which will be found all the proofs that 
 can be adduced in favor of my opinion. 
 
 Consecutive sclerosis resulting from cerebral lesion ac- 
 
 the entire lateral system, including not only the cerebro-spinal and pyramidal 
 fibres, but also those fibres which both commence and terminate in the spinal 
 cord those fibres properly called spinal fibres. 
 
 1 Permanent contraction of the limbs, as is seen in other complaints, such ds hys- 
 teria, may exist without lateral spinal sclerosis ; but when that lesion exists, per- 
 manent contraction is an habitual symptom, 
 
 9 
 
130 DISEASES OF THE BRAIN. 
 
 quires, after a given time, a kind of independent existence, 
 automatic ; this is evinced by special symptoms. By reason 
 of this autonomy the lesion may happen to extend beyond 
 the limits habitually assigned to it in the lateral fasciculus, and 
 invade the adjacent parts of the spinal cord, the substance of 
 the gray cornua, for example ; in such cases it is comprehen- 
 sible that important modifications may occur in the symp- 
 tomatic tableau ; thus, the muscles of the paralyzed limbs, 
 which in permanent hemiplegia ordinarily preserve their nor- 
 mal texture for a long time, and but slowly emaciate, are 
 subject, in certain cases, to a degenerative atrophy, more or 
 less rapid, at the same time that the rigidity of the contrac- 
 tion gives way to renewed flaccidity. In several examples 
 of this kind, Pierret and I have demonstrated, in addition to 
 the classic lateral sclerosis, a lesion of the anterior gray cornu 
 of the same side, including the destruction of the large nerve- 
 cells of that region. The invasion of the posterior gray cor- 
 nu might in like manner explain the appearance of certain 
 partial anaesthesia in common hemiplegia. Lastly, the exten- 
 sion of the initiative process, whether along the whole course 
 of the lateral fasciculus of the corresponding side, or be it of 
 the lateral fasciculus of the opposite side, would doubtless ex- 
 plain the fact that, contrary to common observation, the con- 
 traction of the lower limb is at some one period considerably 
 greater, or sometimes extends to the opposite limb. 1 
 
 V. To the present I have only occupied myself with fas- 
 cicular sclerosis arising from lesion of the central cerebral 
 masses. I now wish to give a moment to those produced by 
 lesions of the cortex. So far as concerns the affection of the 
 spine or the bulb, lateral sclerosis, from lesions of the cen- 
 tral masses, in no way differs from that following lesions of the 
 cortex. The special conditions of development constitute all 
 the difference, and this calls for new details. 
 
 You remember how you have been led to admit, on the 
 grounds of a very probable hypothesis, the existence of di- 
 
 1 In this connection see Bastian Paralysis from Brain Diseases, etc., p. 141. 
 London, 1875. 
 
SECONDARY DEGENERATION. 131 
 
 rect peduncular fibres that is, those which, after leaving the 
 foot of the peduncle, traverse the internal capsule without 
 entering the gray ganglia of the central masses, and conse- 
 quently do not stop until they reach the gray cortical sub- 
 stance ; besides the arguments already employed, some facts 
 of experimentation can be cited in favor of the existence of 
 such fibres, even with animals of low scale, the rabbit for ex- 
 ample. Thus in the experiments already noticed of Gudden, 1 
 made upon very young animals, it is seen that eight months 
 after the removal of the anterior part of a hemisphere, the 
 central masses, thalami optici, and corpora striata being un- 
 touched, the internal capsule of the corresponding side atro- 
 phies in a remarkable manner. It is clear that such atrophy 
 would not occur if the internal capsule, as some anatomists 
 hold, were exclusively composed of indirect peduncular fibres, 
 that is, of fibres terminating in the substance of the central 
 gray ganglia. 
 
 Chance brought to the notice of Carville and Duret 2 a 
 lesion in a dog which had destroyed all the white substance 
 of the frontal portion of a lobe without directly affecting the 
 central gray ganglia or the internal capsule. In this case 
 there was a very marked atrophy of the foot of the peduncle, 
 the protuberance, and of the pyramidal bulb of the side" cor- 
 responding to the cerebral lesion. 
 
 The reality of these direct peduncular fibres in man seems 
 in its turn to be proven by the production of the secondary 
 degenerations which, as we have said, are a result of exten- 
 sive and deep lesions of the gray cortical substance. 
 
 Do these direct peduncular fibres, after their disappearance 
 in the diverging fibres, spread indifferently to all parts of the 
 hemisphere, or are they assigned to special departments of 
 the gray cortex ? The facts which I have collected towards 
 the study of that question plead in favor of the last hypothe- 
 sis. These observations, collected for me at the Hospital of 
 Saltpetriere during the last fifteen years, relate to cases of 
 
 1 Archiv fur Psychiatric, Bd. II., 1870, pi. VIII. 
 3 Archives de physiologic, 1875. 
 
132 
 
 DISEASES OF THE BRAIN. 
 
 long-standing ischaemic softening. 1 The lesions in these cases 
 appeared as yellow patches of variable size, extending more 
 or less deeply into the subjacent white substance and occu- 
 pying the most diverse regions of the surface of the hemi- 
 spheres. In all the cases it is expressly mentioned that the 
 softenings had left the central masses, thalami optici, cau- 
 dated and lenticular ganglia, and internal capsule, entirely 
 untouched. My observations may be divided into two 
 groups. 
 
 FIG. 45. Human brain, left side ; destruction of the ascending parietal convolu- 
 tion and a great part of the ascending frontal convolution. 
 
 The first includes those cases where no permanent hemi- 
 plegia existed during life, and where autopsy discovered no 
 consecutive degeneration. In all these cases the convolu- 
 tions fed by the Sylvian artery, and especially the ascending 
 frontal and parietal convolutions, had remained unharmed. 
 The yellow patch occupied one of the following regions, 
 namely, some part of the sphenoidal lobes, the quadrilateral 
 lobule, the cuneus, one or both of the occipital lobes, and a 
 region ranging over the anterior two-thirds of the frontal 
 lobes. 
 
 1 The most of these observations are accompanied by designs made from nature ; 
 it can be understood that the place and extent of the lesion are thus more exactly 
 located, and consequently the ordinary insufficiency of description is avoided. 
 
SECONDARY DEGENERATION. 133 
 
 In all cases of the second group, there had been, on the 
 contrary, a permanent hemiplegia, and the consecutive sclero- 
 sis was perfectly marked. The distinguishing feature of these 
 cases was, that the lesion always involved more or less one or 
 the other of the ascending frontal or parietal convolutions, 
 chiefly in their superior half, and often both of the convolu- 
 tions were at the same time affected ; besides, the regions 
 nearest to the frontal and parietal convolutions generally 
 participated. The design which I place before you is a very 
 marked example (Fig. 45). 
 
 From the preceding, as I before said, it would seem that 
 secondary sclerosis, resulting from destructive lesions of the 
 cerebral cortex, are subordinate to location. I will add, in 
 conclusion, that those portions of the cortex a lesion of 
 which determines secondary degenerations exclusively, cor- 
 respond to those parts which experimentation with the mon- 
 key has designated as the psycho-motor centres. They are 
 the same also where the gray cortical substance contains the 
 largest pyramidal cells. 
 
 I have brought into relief an important fact, which should 
 be utilized in the study of localization in the cerebral cortex ; 
 a difficult study which we will attempt in our next lectures. 
 

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