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THE 
 
 ANATOMY OF THE BRAIN, 
 
 WITH 
 
 A GENERAL VIEW 
 
 c; / ' 
 
 k* v- v. mJJ 
 
 OF THE 
 
 NERVOUS SYSTEM. 
 
 BY 
 
 G. SPURZHEIM, M.D. 
 
 OP THE UNIVERSITIES OP VIENNA AND PARIS; LICENTIATE OF THE ROYAL COI.LEOE OP 
 PHYSICIANS IN LONDON. 
 
 TRANSLATED FROM THE UNPUBLISHED FRENCH MS. 
 
 By R. WILLIS, 
 
 MEMBER OP THE ROYAL COLLEGE OP SURGEONS IN LONDON. 
 
 WITH ELEVEN PLATES. 
 
 LONDON : 
 
 PUBLISHED BY S. HIGHLEY, 174, FLEET-STREET, 
 
 and Webb- Street , St. Thomas’s Hospital ; 
 
 SOLD ALSO BY HILL AND SON, EDINBURGH; AND CHARLES 
 ARCHER, DAME-STREET, DUBLIN. 
 
 MDCCCXXVI. 
 
LONDON: 
 
 PRINTED BY WILLIAM CLOWES, 
 Northumberlanc -court. 
 
 
Preface ......... vii 
 
 Section I. — General Considerations ... 1 
 
 Of the Existence of the Pulpy and Fibrous Sub- 
 stances ........ 2 
 
 Of the Structure of the Two Nervous Substances . 3 
 
 Of the Use of the Pulpy Nervous Substance . 6 
 
 Of the Origin of the Nervous System ... 10 
 
 Of the Mode of Formation of the Nervous System . 16 
 
 Of the General Form of the Nervous System . IS 
 
 Of the Structure and Use of Ganglions . . .19 
 
 Section II. — Division of the Masses composing the 
 
 Nervous System ..... 23 
 
 Section III. — Of the Nervous Masses of Voluntary 
 
 Motion, and of the External Senses . . 36 
 
 Of the Nervous Mass of the Vertebral Column . 50 
 
 Of the Pretended Cerebral Nerves ... 68 
 
 Of the Quadrigeminal Bodies .... S3 
 
 Section IV. — Of the Best Method of Dissecting the 
 Brain ........ 95 
 
 Section V. — Of the Cerebellum . . . 106 
 
 Section VI. — Of the Brain ..... 143 
 
 Decussation of the Anterior Pyramids . . 146 
 
 Two portions of the Crura and Cerebral Masses 153 
 
VI 
 
 CONTENTS. 
 
 PAGE 
 
 Comparative Anatomy of tlie Brain . . . 159 
 
 Structure of the Convolutions . . . .163 
 
 Section VII. — Of the Commissures of the Nervous 
 
 Apparatuses . . . . . . 178* 
 
 Section VIII. — Of the Communications of the Ner- 
 vous Apparatuses . . . . .195 
 
 Section IX. — Of the Anatomico-Physiological Rela- 
 tions of the Nervous Apparatuses . . 204 
 
 Explanation of the Plates and Figures . . .216 
 
PREFACE. 
 
 The affective and intellectual faculties of man, 
 both in their healthy and diseased condition, 
 are unquestionably dependent on the body ; 
 and, among the various branches of anthro- 
 pology, anatomy is the basis of all the others. 
 The organic apparatuses, which are indis- 
 pensable to the mental manifestations, con- 
 sist of the brain, cerebellum, spinal cord, and 
 the nerves of the external senses and vo- 
 luntary motion. To make known the struc- 
 ture of these parts is the special object of 
 this volume. 
 
 History proves that the structure and des- 
 tination of the nerves were long unknown. 
 Hippocrates and Aristotle, for instance, con- 
 founded, under the same general title, liga- 
 ments, tendons, nerves, and even blood-ves- 
 sels. Hippocrates believed that the nerves 
 terminated in muscles and bones, and pro- 
 duced voluntary motion. Herophilus, who 
 lived nearly three centuries before the com- 
 
Viii PREFACE. 
 
 mencement of the vulgar era, was the first 
 who discovered the connexion of the nerves 
 with the brain, and who looked on them as 
 the instruments of sensation. Erasistratus 
 divided the nerves into those of sensation and 
 those of motion ; the first he derived from 
 the brain, the second from the membranes. 
 Galen held that the nerves of sensation arose 
 from the brain, and those of voluntary mo- 
 tion from the spinal cord. In the sixteenth 
 and succeeding centuries the brain and nerves 
 were subjects of much research, but it is only 
 in our own times that they have begun to be 
 understood, — that their true structure has 
 been discovered, and that new and unthought- 
 of functions have been proved to belong to 
 them. 
 
 The nervous being the most delicate tis- 
 sues of the body necessarily required ex- 
 tremely careful and often-repeated examina- 
 tion to be understood, and this they could 
 not receive during ages when prejudice op- 
 posed insurmountable obstacles to the dissec- 
 tion of dead bodies. It is therefore easy to 
 conceive why such slow progress was made 
 in the anatomical knowledge of the nervous 
 system. 
 
PREFACE. 
 
 IX 
 
 Dr. Gall is the original author of a new 
 physiological doctrine of the brain. The 
 discovery of the ground-work of this is all 
 his own, and he had even gone very far in 
 rearing the superstructure before the year 
 1804, when I became his colleague. From 
 this period we continued labouring in common 
 until 1813, when our connexion ceased, and 
 each began to pursue the subject for himself. 
 The works which Dr. Gall has published in 
 his own name fix the extent of his phrenolo- 
 gical knowledge. My ideas, too, are deve- 
 loped in my own publications : history v/ill 
 assign to each of us his share in the works 
 that have issued under our joint names. 
 
 It was in the year 1800 that I attended for 
 the first time the private course of lectures 
 which Dr. Gall had been in the habit of deli- 
 vering occasionally at his house for four 
 years. At this time he spoke of the necessity 
 of the brain to the manifestations of mind, of 
 the plurality of the mind’s organs, and of the 
 possibility of discovering the development of 
 the brain by the configuration of the head. 
 He pointed out several particular organs of 
 different memories, and of several sentiments, 
 but he had not yet begun to examine the 
 
X 
 
 PREFACE. 
 
 structure of the brain*. Between 1800 and 
 1804 he modified his physiological ideas, and 
 brought them to the state in which he pro- 
 fessed them at the commencement of our 
 travels •f. 
 
 Dr. Gall having met with a woman, fifty- 
 four years of age, who from her infancy had 
 laboured under dropsy of the brain, and who, 
 nevertheless, was as active and intelligent as 
 the generality of females in her own rank of 
 life, and being convinced that the brain was 
 the indispensable organ of the soul, expressed 
 himself in terms similar to those which Tul- 
 pius had used before him, on observing a 
 person afflicted with hydrocephalus, who ex- 
 hibited good intellectual faculties, viz., the 
 structure of the brain must be different from 
 what it is commonly supposed to be. He 
 now felt the necessity of examining the 
 mind’s organ anatomically. As his medical 
 practice occupied his time, he employed M. 
 Niclas, a student, to dissect for him ; but the 
 
 * Exposition cle la Doctrine de M. Gall, par Froniep, 3mc 
 edit. 1802. 
 
 t Bisclroff Exposition de la Doctrine de M. Gall, sur le Cer- 
 eau et le Crane, Berlin, 1S05 ; et Bloede, la Doctrine de Gall 
 suv les Fonctions du Cerveau, Dresden, 1805. 
 
PREFACE. 
 
 XI 
 
 spirit of this gentleman’s researches was 
 merely mechanical, as is allowed in our joint 
 work, entitled “ Anatomie et Physiologie du 
 Systeme nerveux en general, et du Cerveau 
 en particular*.” 
 
 Having completed my studies in 1804, I 
 was associated with Dr. Gall, and devoted 
 myself especially to anatomical inquiries. At 
 this period, Dr. Gall, in the Anatomy, spoke 
 of the decussation of the pyramidal bodies, 
 of their passage through the pons Varolii, of 
 eleven layers of longitudinal and transverse 
 fibres in the pons, of the continuation of the 
 optic nerve to the anterior pair of the qua- 
 drigeminal bodies, of the exterior bundles of 
 the crura of the brain diverging beneath the 
 optic nerves in the direction which Vieussens, 
 Monro, Vicq d’Azyr, and Reil *f* had followed, 
 the first, by means of scraping, the others, 
 by cutting the substance of the brain. Dr. 
 Gall shewed further, the continuation of the 
 anterior commissure across the striated bo- 
 dies ; he also spoke of the unfolding of the 
 brain that happens in hydrocephalus. The 
 notion he had conceived of this, however, 
 
 * Preface to the first vol. p. 16. 
 
 f Gren’s Journal, 1795, i. p. 102. 
 
Xll 
 
 PREFACE. 
 
 was not correct ; for he thought that the con- 
 volutions resulted from the duplicature of a 
 membrane, believing that the cerebral crura 
 entered the hemispheres on one side, expanded 
 there, and then folded back on themselves 
 by the juxtaposition of the convolutions. 
 The true structure of the convolutions, and 
 their connexion with the rest of the cerebral 
 mass, were not described until our joint Me- 
 moir was presented to the French Institute 
 in 1808. 
 
 The mechanical direction which the ana- 
 tomical investigations had taken did not ap- 
 pear to me satisfactory. Guiding myself in 
 my inquiries by physiological views, always 
 comparing structure with function, I disco- 
 vered the law of the successive additions to 
 the cerebral parts ; the divergence in every 
 direction of the crural bundles towards the 
 convolutions ; the difference between the di- 
 verging fibres and those of union ; the gene- 
 rality of commissures ; the true connexion 
 of the convolutions with the rest of the cere- 
 bral mass, and the peculiar structure which 
 admits of the convolutions being unfolded 
 (an event that occurs in hydrocephalus of the 
 cavities), whilst the mass lying at their bot- 
 
PREFACE. 
 
 Xlll 
 
 toms, and belonging, for the most part, to 
 the apparatus of union, or of the commis- 
 sures, is pushed by the water between the 
 two layers composing them ; lastly, I demon- 
 strated the structure of the nervous mass of 
 the spine, and I flatter myself with having 
 arrived at the best method of dissecting the 
 brain, and exposing its parts. 
 
 What is my object then in publishing this 
 volume ? Our large work is too expensive 
 for the generality of medical students, and, 
 further, the method pursued in the discus- 
 sions there is only calculated for professed 
 anatomists ; whilst this book will be both 
 less costly, and it will be adapted to the stu- 
 dent as well as to the more advanced anato- 
 mist. Moreover, many new ideas, possess- 
 ing a great share of interest, may now be 
 added ; for since Dr. Gall and I first pub- 
 lished, the study of the nervous system has 
 engaged the especial attention of anatomists 
 and physiologists. I have, myself, continued 
 inquiring, and conceive that I have made se- 
 veral new discoveries. I have, however, 
 copied some passages from the first volume 
 of the large work already mentioned, and 
 also given reduced drawings of several of its 
 
xiv 
 
 PREFACE. 
 
 plates ; because I think I have acquired a 
 right to this volume, by its publication in our 
 joint names, by my discoveries that form its 
 principal object, and by all I did in further- 
 ance of its publication. All the drawings 
 were executed under my superintendence 
 from anatomical preparations, made and de- 
 termined on by me ; the engraver worked by 
 my directions ; no plate was sent to press 
 without my approval ; the descriptions of the 
 plates, and the anatomical details are mine ; 
 and I furnished the literary notices in regard 
 to the nerves of the abdomen and thorax, to 
 those of the vertebral column, of the five 
 senses, of the cerebellum, and of the brain. 
 
 Whoever desires more copious historical 
 details than this volume will be found to 
 contain, I refer to our Memoir, addressed to 
 the French Institute, and to the first volume 
 of our great work, commenced in common, 
 and continued .by Dr. Gall singly after the 
 middle of the second volume. 
 
 The influence our labours have had on the 
 study of the nervous system is incontestable. 
 To be convinced of this, it is enough to ex- 
 amine the state of knowledge in regard to the 
 anatomy, physiology, and pathology of the 
 
PREFACE. 
 
 XV 
 
 brain and spinal marrow, when Dr. Gall and 
 I developed our ideas on these matters, 
 whether it was by teaching orally, by dis- 
 secting publicly, or by means of our writings. 
 I confess there is great satisfaction in the 
 consciousness of having contributed to the 
 important reform that has been effected in 
 regard to the nervous system. I am only 
 sorry to observe, that many of our ideas are 
 appropriated by the authors of recent publi- 
 cations, without any mention of the source 
 whence they were derived, or of the indivi- 
 duals who first struck them out, or reduced 
 them to certainty by direct proofs. We are 
 commonly enough mentioned, it is true, 
 when such of our assertions as appear weak 
 are the subjects of criticism, but our names 
 are kept in the background when points of 
 importance become the matter of discussion. 
 The public, for instance, by referring to the 
 proper place, may judge whether Mr. J. 
 Cloquet, in his £t Anatomy of Man/’ has been 
 sufficiently explicit in stating, that he has 
 copied every one of the plates of the human 
 brain contained in our large work. M. Ser- 
 res, whose Memoir was deemed worthy of 
 its prize by the Academy of Sciences of 
 
XVI 
 
 PREFACE. 
 
 Paris, in the first volume of his work, uses 
 our names no fewer than fifteen times, in 
 connexion with a single idea which he 
 fancies he can refute; and generally along 
 with every fact that looks unfavourable to 
 our opinion, he names us, but he always 
 forgets to cite us in relation to very many 
 fundamental conceptions which we had an- 
 nounced at the same time. They who have 
 written to the following effect:— “ M. Serres 
 has proved clearly the erroneousness of 
 M. Gall’s observations, and replaced them 
 by others,” may undeceive themselves by at- 
 tending to the remark I have just made. 
 
 M. Serres’s publication forces me likewise 
 to request the reader to distinguish between 
 a multitude of words and facts on the one 
 hand, and the corollaries which result on the 
 other. I agree with those who, in works of 
 science, pay especial regard to truths de- 
 monstrable to others, to ideas available in 
 practical life, and to clearness and simplicity 
 of style. To what purpose may serve the 
 following passage, which occurs in the pre- 
 liminary discourse of M. Serres, where, 
 after having said that a monster may be a 
 vegetation of its like, that it may have 
 
PREFACE. 
 
 XVII 
 
 two heads, two tails, and six or eight ex- 
 tremities, but that it would remain strictly 
 confined to the limits of its class, he ex- 
 claims : — “ This wonderful 'phenomenon is un- 
 doubtedly connected with the general harmony 
 of creation. What may be its cause ? We 
 know it not, and in all likelihood we shall re- 
 main ignorant of it for ever. It is one of 
 the mysteries of creation , whose surface is 
 meted by man, but whose depths are sounded, 
 and known to God alone 
 
 This phenomenon does not appear to me 
 more extraordinary than that a kitten is not 
 a puppy, or that the crab-tree does not pro- 
 duce pears. If the egg of a bird in its or- 
 dinary state cannot produce a mammiferous 
 animal, why should the germ of this same 
 egg, if it chance to be imperfectly developed, 
 produce a deformity like to one of the mam- 
 malia? Were the case thus, there would be 
 some cause for an amazement, but the univer- 
 sal fact of every animal producing its kind, 
 
 * “ Cetetonnant phdnomene est sans doute lid a l’harmonie 
 generale de la creation. Quelle peut en etre la cause ? Nous 
 l’ignorons et vraisemblablement nous l’ignorerous toujours. 
 C’est un des mysteres de la creation, dont l’homine mesurela 
 surface, mais dont Dieu seul sonde et connait la profondeur.” 
 
XV111 
 
 PREFACE. 
 
 is not, in my eyes, more astonishing than any 
 other natural event. 
 
 Further, the mass of facts cited, the num- 
 ber of dissections made, ought never to im- 
 pose on us, nor be made a means of concealing 
 the truth. Many of the anatomists who had 
 lived before us dissected some hundreds of 
 brains, and they made a boast of their doings 
 in this way ; but they did not perceive that 
 which I pledge myself to have discovered 
 before I had dissected a dozen ; for instance, 
 the successive additions to the cerebral parts, 
 and the two kinds of fibres, to wit, the di- 
 verging, and the fibres of union. Anatomists 
 and physiologists had certainly looked upon 
 heads without number ; but before Dr. Gall’s 
 appearance, had failed to discover the seat 
 of a single cerebral organ. A solitary indi- 
 vidual, a beggar, enabled him to detect the 
 organ of self-esteem, precisely as the fall of 
 a single apple revealed the law of gravita- 
 tion to Newton. Anatomists had seen many 
 human brains without remarking any differ- 
 ences among them ; these, however, are, to 
 say the least, as constant as similarities. The 
 point that essentially interests science is, the 
 
PREFACE. 
 
 XIX 
 
 discovery of the truth, and this is then con- 
 firmed and established by all ulterior obser- 
 vations. 
 
 The anatomy of the peculiar system ne- 
 cessary to the affective and intellectual ma- 
 nifestations, as well as anatomy in general, 
 admits of consideration in several ways. 
 
 First, it is simply descriptive, that is, phy- 
 sical appearances alone are examined, such 
 as the form, the size, and colour of parts, 
 the tissues which compose them, and their 
 connexions. 
 
 The nomenclature of the encephalon, of 
 itself suffices to shew that such views had 
 principally guided anatomists in their study 
 of its structure. We still speak of the' brain, 
 of the cerebellum, of hemispheres, lobes, 
 convolutions, and anfractuosities ; of a for- 
 nix, an infundibulum or funnel, and of pi- 
 siform and striated, and quadrigeminal and 
 pyramidal, and olivary and harrow-shaped 
 bodies ; of a pineal gland, of a hippocampus's 
 foot, of a writing-pen, and many other parts, 
 some with very offensive names. Such views 
 are easily conceived to be but little useful in 
 medicine. This is the reason why the gene- 
 
XX 
 
 PREFACE. 
 
 rality of practitioners are satisfied with know- 
 ing the membraneous envelopes of the ence- 
 phalon, the large blood-vessels, the sinuses, 
 the great masses of the brain and cerebellum, 
 and the principal cavities. Of these views, 
 however, I shall only take such notice as 
 may be necessary to recognize the parts 
 spoken of in my physiological and pathologi- 
 cal considerations. 
 
 M. Serres, in the first page of his work on 
 the Anatomy of the Brain, says, “Up to the 
 present time, (1824,) no one has dreamt o 
 uniting into a body of doctrine all the know- 
 ledge acquired on the anatomy, the physiology 
 and the pathology of the brain and nervous 
 system. I enter on the attempt to overtake 
 this vast subject Dr. Gall’s and my own 
 works belie this assertion, and they have only 
 to be consulted to prove that all our inquiries 
 were directed into this very channel. We 
 have constantly insisted on the importance 
 of studying the nervous system under all re- 
 lations at once. From the year 1817 to 1823, 
 
 * “ Jusqu’a ce jour (1824) personne n’a songe a reunir en 
 corps de doctrine les connaissances acquises sur l’anatomie, la 
 physiologie et la pathologie du systcme nerveux, Je vais 
 essayer de parcourir ce vaste sujet.” 
 
 *-+5 
 
preface:. 
 
 xxi 
 
 I regularly delivered “ a Course of Lectures on 
 the Anatomy, Physiology, and Pathology of the 
 Brain and External Senses ,” twice a year. My 
 course was always so announced, according 
 to the custom in Paris, by public placards ; 
 and my auditors must recollect that in my 
 introductory discourse, I uniformly insisted 
 on the importance and necessity of studying 
 these branches in connexion. From the above, 
 it will be evident that M. Serres was mistaken 
 when he published himself “ the first to at- 
 tempt to overtake (essay er de par courir) this 
 vast subject/’ Nevertheless, I most willingly 
 allow that the principal consideration is not 
 the having been the first to examine the ner- 
 vous system : the true merit of the inquirer 
 consists in that which he has effected, that 
 which he had discovered, and justice in these 
 particulars will, in time, be assuredly ren- 
 dered to all. If, on occasion, I seem more 
 especially solicitous in shewing the errone- 
 ousness of M. Serres’s opinions, it is only 
 because these have received the sanction of 
 the French Institute, whose influence is great 
 over the public mind. 
 
 2. Anatomy is physiological, when the 
 
XXII 
 
 PREFACE. 
 
 structure of parts is studied in relation to 
 their functions. This kind of anatomical know- 
 ledge is essentia] to practical medicine ; for 
 without it, the seat of deranged functions 
 cannot be understood. For this reason, there- 
 fore, my anatomical details will always be 
 given in harmony with the physiological ideas 
 I entertain of the apparatus destined to the 
 manifestation of the affective and intellectual 
 faculties. 
 
 3. Anatomy is peculiarly human, or, it 
 comprehends the other beings of creation. In 
 the latter event, it is entitled comparative 
 anatomy, and this is a field that possesses 
 much interest for the anatomist, physiologist, 
 and practical physician ; I shall, therefore, 
 enter upon it at frequent intervals, always 
 with the view of advancing the knowledge 
 on the affective and intellectual nature of 
 man. 
 
 4. Anatomy is entitled pathological , when 
 it treats of the organic changes undergone by 
 parts whether examined in connexion with, 
 or independently of, their deranged functions. 
 Inquiries in this direction belong less to the 
 present volume, than to that I have published 
 
PREFACE. 
 
 XX111 
 
 on Insanity. To it, therefore, I refer the 
 reader for details. 
 
 The object of this compendium, then, is to 
 present the principal views that may be taken 
 of the physiological and comparative anatomy 
 of the apparatus destined to the affective and 
 intellectual manifestations. It will be found 
 divided into nine sections: — in the first, I 
 make some general reflections on the nervous 
 system ; in the second, I speak of the division 
 of the nervous apparatuses ; in the third, I 
 treat of the nerves of voluntary motion and 
 of the external senses ; in the fourth, I discuss 
 the best mode of examining the structure of 
 the brain ; in the fifth, I describe the cere- 
 bellum particularly ; in the sixth, I do the 
 like in regard to the brain ; in the seventh, 
 I examine the commissures ; in the eighth, 
 the communication of the nervous parts with 
 each other ; and in the ninth, I go into some 
 anatomical points connected with physiology. 
 The work will prove that I rather adhere to 
 philosophical views and principles, than to 
 mere description of the physical qualities 
 belonging to individual masses, although this 
 last be the most common, I might almost say 
 
XXIV 
 
 PREFACE. 
 
 the only, plan that is generally pursued. I 
 have endeavoured, in an especial manner, to 
 class together the parts that constitute parti- 
 cular apparatuses, a practice which to our 
 predecessors was entirely unknown, as is 
 abundantly evident from their nomenclature 
 of the brain and its parts. 
 
ANATOMY OF THE BRAIN, 
 
 fr- 
 
 Section I. 
 
 General Considerations. 
 
 Nerves are whitish cords that pervade the 
 bodies of the more perfect animals ; they are 
 always made up of many filaments, each of 
 which, however minute, is a tube that holds in 
 its interior a peculiar pulpy substance, consti- 
 tuting one among the elements of organization. 
 It is to a multitude of such tubular filaments, 
 enveloped in a common sheath, that the term 
 nervous cord, or nerve, is usually applied. These 
 cords, as well as their component filaments, vary 
 much in thickness and consistency. The last 
 quality depends entirely on the texture of the 
 enveloping membrane. 
 
 The nervous system comprises two distinct 
 substances : the one gelatinous or pulpy, and 
 usually of a grayish or brownish hue ; the other 
 fibrous, and of a more or less perfect white 
 
 B 
 
2 
 
 colour. They are commonly spoken of in books 
 as the cineritious and medullary substances. 
 
 Of the Existence of the Pulpy and Fibrous 
 Substances. 
 
 Comparative anatomists are not agreed upon 
 the constantly-conjoined existence of the two ner- 
 vous substances. Some admit the presence of 
 the white without that of the gray, especially in 
 the spinal mass of many inferior animals, as 
 reptiles and fishes. The nervous ganglions 
 of the asterice are also said to contain no gray 
 matter. 
 
 The above observation is evidently made in 
 consequence of more attention being given to the 
 colour than to the essential nature of the pulpy 
 substance. Pulpiness, not colour, is its distin- 
 guishing character. There are animals whose 
 humours, or, as was formerly said, whose blood 
 is white. The essential consideration is evi- 
 dently, in this case, the existence, not the colour, 
 of the nutritious fluid. Should it not also be so 
 in regard to the first or pulpy nervous substance, 
 which in the majority of animals is of an ash- 
 gray or brown colour ? Undoubtedly it should, 
 for it is well known to vary in complexion, not 
 only in different species of animals, but even in 
 individuals of the same kind, according to their 
 state of bodily health. The pulpy substance is 
 
3 
 
 commonly extremely pale in the brains of those 
 who die of dropsy or pulmonary consumption. 
 
 The pulpy substance is found in the ganglions, 
 and in the nervous masses of the head and 
 spine of vertebral animals. In the mammiferous 
 classes especially, it occurs on the surface of all 
 the convolutions of the brain and cerebellum, (a 
 circumstance from which it derives its title, cor - 
 tical,) in the masses called striated bodies, and 
 optic thalami, in the interior of the crura of the 
 brain, of the annular pro" £U >erance, of the dentated 
 body, of the cerebellum, of the medulla oblongata, 
 of the spinal cord through its entire length, and of 
 all the ganglions of the body. It never of itself 
 composes an isolated unit or whole, it is always 
 in connexion with the white or fibrous sub- 
 stance. Occasionally it lies in masses of varying 
 magnitude, and again it occurs in layers, or it 
 runs along in slips following the nerves in their 
 course. 
 
 Of the Structure of the two Nervous Substances. 
 
 The first nervous substance is pulpy or gelati- 
 nous, and of a colour varying from deep brown to 
 pale ash-gray or white. Its intimate structure 
 is unknown. Ruysh, Vieussens, and almost all 
 the cotemporaries of Haller, regarded it as a 
 tissue of very fine blood vessels. Ackermann of 
 Heidelberg, and Walter of Berlin, in our own 
 
 B 2 
 
times, have held it to consist of an extremely-at- 
 tenuated prolongation of vessels, in the course of 
 becoming still more minute, ultimately to com- 
 pose the white or fibrous substance. This is a 
 very ancient idea ; it may be traced as far back 
 as the age of Praxagoras, who fancied that the 
 nerves originated where the arteries ended. Al- 
 binus, and, at a later period, Scemmerring, have 
 proved by their injections, that besides very mi- 
 nute blood-vessels, there also exists a peculiar 
 substance in the emeritus nervous mass. The 
 first or pulpy substance, therefore, can only be 
 said to have an immense quantity of blood-ves- 
 sels distributed through it. 
 
 Vicq d’Azyr believed that he could trace 
 fibres in the pulpy substance ; but what he saw 
 was the white or truly fibrous substance, inter- 
 mingled or uniting with the gray. 
 
 The second, or white, nervous substance, is 
 essentially fibrous, but it varies much in its de- 
 grees of consistency. Anatomists have differed 
 extremely in their notions of its intimate struc- 
 ture. Some have maintained it to be solid, 
 others have said that it was tubular. Some have 
 found it, like the pulpy substance, composed of 
 globules ; and whilst some have held it possessed 
 of no blood-vessels, others have argued for its 
 entire composition of these. 
 
 Lewenhoeck, Yieussens, and Steno, believed 
 that the white nervous substance was fibrous. 
 
5 
 
 This is the opinion which Dr. Gall and I have 
 espoused. By scraping it in the brain according 
 to the direction of its fibres, these may be seen 
 with the naked eye, and if the scraping mo- 
 tion be oblique or transverse to their course, 
 they will be seen to be drawn from their na- 
 tural direction, or to be torn. If the brain be 
 boiled in oil, or macerated in diluted nitric or 
 muriatic acid, or in vinegar, or alcohol, or if 
 it be frozen, the fibrous structure of its white 
 substance will be rendered extremely apparent. 
 Some, however, say, that the fibrousness is then 
 the consequence of a chemical change. As the 
 same result, however, is constantly obtained, and 
 as the fibres, whichever of the processes be 
 employed, are regularly disposed in correspond- 
 ing situations in a similar manner, the fibrous 
 structure must of necessity be recognised as na- 
 tural and inherent. 
 
 A few authors have attributed the fibrous ap- 
 pearance of the white substance to the impres- 
 sions of blood-vessels. This mistake may be de- 
 tected at once by comparing the course of the 
 blood-vessels with that of the cerebral fibres. 
 
 The reality of the fibrousness of the white 
 substance is further opposed, by saying that 
 when the brain is cut, it does not appear, and that 
 it is produced by the force employed to tear the 
 tougher cerebral masses asunder. 
 
 To this I reply, that it is impossible, by means 
 
6 
 
 of a clean and smooth cut, to discover the struc- 
 ture of any extremely delicate and soft part 
 whatsoever. Such a method is not even available 
 in those cerebral parts that are incontestably 
 fibrous, as the pyramidal bodies, the annular pro- 
 tuberance, the peduncles of the brain, &c. 
 
 M. Bogros, of Paris, read a paper to the Aca- 
 demy of Sciences, on the 25th of May, 1825, in 
 which he maintained that every nervous fibre is 
 perforated by a canal from its origin to its ex- 
 treme termination. The accuracy of this state- 
 ment is far from being ascertained. 
 
 The white nervous substance is generally 
 called medullary. This name, however, ought to 
 be discontinued for two reasons : in the first 
 
 i 
 
 place the idea we form of marrow excludes the 
 conception of fibrousness ; and again, the func- 
 tions of the nervous fibres are so superior to those 
 of the marrow, that it is a pity to designate both 
 by the same word. The name is evidence of the 
 error that was anciently committed, when every 
 thing contained in an osseous cavity was consi- 
 dered as marrow. 
 
 Of the Use of the Pulpy Nervous Substance. 
 
 Different opinions have prevailed ever since 
 the times of Vesalius and Piccoluomini, who di- 
 rected the attention of anatomists in a particular 
 manner to this subject, respecting the use and 
 
7 
 
 destination of the pulpy or gray substance. It 
 has frequently been regarded as an organ of se- 
 cretion, whether of vital spirits or of a nervous 
 fluid. Unity of sentiment, it is probable, will 
 not be readily obtained upon this particular 
 point: but seeing that the rudiments of each 
 new shoot in trees are developed in a deposition 
 of mucilaginous-looking matter ; that the carti- 
 lages in animal bodies are successively liquid, 
 gelatinous, and cartilaginous, and that several 
 turn into firm bone ; that anatomists, in many in- 
 stances, have agreed in deriving the nerves from 
 ganglions ; that the brain, too, is at first fluid, 
 then gelatinous, and ultimately fibrous ; in fine, 
 that the pulpy nervous substance is always found 
 where the white fibres become more numerous ; 
 that these are implanted, so to say, into it, and 
 that a great quantity of blood-vessels are ex- 
 panded on it ; Dr. Gall and I have said, that to 
 us it appears to be the source or nourisher of 
 the white fibres. Let us, however, distinguish 
 in this, as in every other place, between facts 
 and inferences. Supposing that our ideas con- 
 cerning the inference were really inexact, the 
 peculiarities I have mentioned, and the essen- 
 tial importance of the pulpy substance to the 
 nervous functions, must ever be admitted. 
 
 Having said that a gray colour is not an essen- 
 tial in the character of the pulpy substance, no ob- 
 jection to our notions of its uses can be derived 
 
s 
 
 from the fact of its supposed absence in the gan- 
 glions of the asterice. A gelatinous or pulpy matter 
 does certainly enter into their constitution, and 
 this is sufficient. 
 
 The white substance is also said to be present 
 in the brain and spinal cord before the pulpy or 
 gray appears. If by this the existence of the 
 nervous masses that become white prior to an 
 evident separation into two substances, and to 
 the developement of convolutions, be understood, 
 I agree ; but if the rudiments of the brain, ce- 
 rebellum, and spinal cord, be said to be white, 
 and not gray in the first instance, I positively 
 deny the assertion. The nervous masses of the 
 head and spine are pulpy or gelatinous, and 
 decidedly grayish in colour before they are 
 white. Neither Dr. Gall nor I have ever thought 
 of saying, that the portion of the completely-de- 
 veloped nervous system, which is pulpy and gray, 
 gives birth to that which is white and fibrous. 
 We did but intend to announce the fact of a ge- 
 latinous and grayish state of the brain preceding 
 its fibrous and white condition, precisely as we 
 should say of its entire mass, that it is liquid 
 before it becomes gelatinous. 
 
 Our idea of the formation of the nervous system 
 seems more especially plausible, when it appears 
 to be perfectly analogous to what takes place in 
 the osseous. Bone begins by being gelatinous, it 
 is then cartilaginous, and ultimately solid and 
 
9 
 
 earthy. I repeat, however, that no one can he 
 more impressed than myself with the difficulty 
 of drawing general conclusions ; I am, there- 
 fore, very far from anxious to impose such as I do 
 infer upon others. I only insist on the necessity 
 of exactness in regard to the facts related. Putting 
 our theory of the formation out of the question 
 entirely, then, Dr. Gall and I still assert our 
 title to be considered as the first who discovered 
 and made known the general relation that pre- 
 vails in man and the mammalia, between the 
 pulpy and fibrous substances of the brain and its 
 several parts. 
 
 Messrs. Foville and Pinel Grandchamp have 
 of late inferred, from pathological observations, 
 that the superficial cineritious substance of the 
 brain presides over intellectual functions, and 
 its white and deep-seated gray mass over loco- 
 motion. 
 
 I am disposed to set much store by patholo- 
 gical observations, yet I do not see that we dare 
 place unlimited confidence in them alone. Truth 
 is, I conceive, universally harmonious ; truth 
 consequently cannot have been attained in any 
 case until anatomy and physiology and patho- 
 logy accord exactly. Now, who will maintain 
 that the locomotive powers of animals are great 
 in proportion as their brains contain more of the 
 white nervous substance, and as the striated bo- 
 dies and the supposed origins of the optic nerves 
 
 * * 
 
10 
 
 (thalami) are large ? Or who will say that the 
 locomotive capacities of inferior tribes, in whose 
 brains the gray substance predominates, are less 
 remarkable than their intellectual endowments ? 
 These positions are alike untenable. Dr. Gall 
 and I suppose that each nervous apparatus is 
 composed of the two peculiar substances, the 
 pulpy and the fibrous, and that both are necessary 
 to produce an instrument adequate to perform a 
 particular function. 
 
 Of the Origin of the Nervous System. 
 
 The brain has very generally been regarded as 
 the sole and common origin of every part of the 
 nervous system. Even the old anatomists, who 
 classed the brain along with the viscera of the 
 chest and belly, and treated of its structure in 
 their chapter of Splanchnology, mistook it, how- 
 ever strange the error may seem, for the source 
 of all the nerves. In their eyes, the spinal cord 
 was a prolongation of the cerebral mass, and the 
 great sympathetic, and the nerves of the abdo- 
 men and thorax, were continuations of the ence- 
 phalon and spinal cord. This erroneous view, 
 as it was espoused, was especially defended, by 
 observing that the commands of the will issued 
 from, and that all consciousness resided in, the 
 brain. These facts, however, do, in truth, prove 
 no more than the communication of the nervous 
 
11 
 
 masses of the body with those of the head. The 
 muscular fibres, we see, are excited by the 
 nerves, but they are not, therefore, continua- 
 tions of the nervous filaments. 
 
 The notion, however, was so palpably erro- 
 neous, that anatomists were not long in calling 
 its soundness in question, more especially in re- 
 gard to the nerves of vegetative life. Winslow *, 
 for instance, separated the great sympathetic 
 from the spinal cord and brain; he even regarded 
 the bundles that run between its ganglions or 
 masses, as simple branches of communication ; 
 and went so far as to say, that all the ganglions 
 ought to be considered as peculiar origins of 
 nerves, and, consequently, as so many little 
 brains. 
 
 Scemmerring likewise observes, that the sympa- 
 thetic, having an independent existence, may 
 rather be said to go to, than to come from, the 
 spinal cord. He adds, that it never forms a 
 trunk in any wise proportionate to the number 
 and size of its communicating branches, and that 
 it never loses itself among muscles, but follows 
 the course of the blood-vessels f . 
 
 Bichat has expressed his opinion in the most 
 positive manner upon this subject. “ The ideas 
 of anatomists,” says he “ upon this important 
 perve, seem to me very little accordant with what 
 
 * Anatomy. f Hirn und Neryen. 
 
 t Sur la Vie et laMort. 
 
12 
 
 nature proclaims to be just. All agree in repre- 
 senting it as a medullary cord, extending from the 
 head to the os sacrum, sending various branches, 
 in its course, to the neck, the chest, and the ab- 
 domen; having, in short, a distribution analogous 
 to the spinal nerve, from which, or from those 
 of the neck, it is said by some to derive its 
 origin. Whatever the name chosen to designate 
 it may chance to be, sympathetic, intercostal, tri- 
 splanchnic, the mode of considering it will still 
 be found to remain unchanged. 
 
 “ This mode I regard as altogether erroneous. 
 In fact there exists no such nerve as these names 
 are used to signify. That which is taken for a 
 nerve is, in truth, but a suite of communications 
 between different nervous centres, situated at va- 
 rious distances from each other. 
 
 “ These centres are the ganglions, scattered 
 through the different regions of the body. They 
 have all an independent and isolated action. 
 Each is a particular magazine, sending a multi- 
 tude of ramifications, to carry into the respective 
 organs the irradiations of the centre whence they 
 proceed. 
 
 “ What anatomist,” he continues, “ has not 
 been struck by differences among the nerves ? 
 Those of the brain are larger, whiter, more dense, 
 less numerous, and offering few varieties ; whilst 
 extreme tenuity, great number, especially around 
 the plexuses, grayish colour, peculiar softness 
 
13 
 
 of tissue, frequently occurring varieties, are, on 
 the other hand, the distinguishing characters 
 of the nerves that issue from the ganglions. 
 The only exceptions in either case are in the 
 branches of communication between the cere- 
 bral nerves, and in a few of the twigs that unite 
 the little nervous centres.” Bichat thought it 
 essential to realize these views in the descrip- 
 tive anatomy. That commonly given is not cal- 
 culated to convey an exact notion, either of the 
 nervous centres, or of the nerves that emanate 
 from them. 
 
 Comparative anatomy, and acephalic monstrosi- 
 ties among the mammalia and man, furnish in- 
 controvertible proofs of the brain not being the 
 origin of the nervous system at large. To com- 
 pare the nervous systems of different tribes is a 
 task attended, with much difficulty ; but very 
 many of the inferior animals have nerves, al- 
 though they have nothing that may be likened to 
 a brain. Their nervous system, consequently, 
 cannot have had the origin commonly assigned 
 to it by authors. 
 
 There are also many anatomical descriptions, 
 to be found in books, of acephalic monsters, of the 
 more perfect animals, and of the human kind, 
 whose nervous system, notwithstanding the ab- 
 sence of brain, was quite perfect. That nerves 
 may exist without a brain is therefore established 
 as a truth beyond the sphere of doubt. 
 
14 
 
 Some writers, however, relying on the autho- 
 rity of Morgagni, Haller, and Sandifort, have 
 maintained that the brains of acephali exist in 
 the first instance, but that dropsy of the cavities 
 destroys the parts, which, at birth, are found 
 wanting, along with the membranes and bony 
 covering. 
 
 But no one ever saw an acephalic child whose 
 brain and skull exhibited traces of such destruc- 
 tion. The integuments of the upper part of the 
 head, where the destructive process is princi- 
 pally supposed, are commonl/'entire and healthy. 
 Neither has any one in these cases discovered 
 the cicatrices of ulcers, nor traces of erosion, 
 nor of simple absorption. The bones that com- 
 pose the basis of the skull, when they exist in 
 acephali, are smooth and round at the edges. 
 The whole inferior part of the encephalic mass, 
 too, and the optic, auditory, olfactory, and other 
 nerves, occasionally occur in a perfectly sound 
 and natural state. How did these nerves and 
 tender cerebral parts resist the action of a fluid 
 that dissolved or caused the absorption of mem- 
 branes and firm bone? It must be allowed then, 
 that the brain may be primitively wanting, just 
 as may the legs or arms, and that the nervous ap- 
 paratus of the body does not derive from the 
 brain. 
 
 The first anatomical principle in regard to the 
 nervous system therefore is, that it is not an unit , 
 
15 
 
 but consists of many essentially different parts, which 
 have their own individual origins, and are mutually in 
 communication. 
 
 This principle Dr. Gall and I regard as essen- 
 tial to our physiological researches and deduc- 
 tions. No anatomist before us was ever so much 
 interested in demonstrating its truth. We con- 
 ceive that we have proved it satisfactorily in re- 
 gard to the brain, as Bichat had done before us, 
 to the nerves of the chest and belly. 
 
 In addition to our first anatomical principle, 
 there are three subjects that require to be taken 
 into consideration separately ; these are, — 1st, 
 The mode in which the individual parts of the 
 nervous system are formed ; 2d, the order of 
 developement of these parts ; and, 3d, their reci- 
 procal relations. 
 
 Dr. Gall and I, in our publications and anato- 
 mical demonstrations, have always spoken of the 
 mode and order in which the cerebral parts are 
 formed and developed ; however, we never 
 touched upon these points but in a general way, 
 our attention being more especially given to the 
 consideration of the plurality of the nervous ap- 
 paratuses, of their communications, and of their 
 mutual relations, the whole in harmony with 
 our physiological and philosophical inquiries. 
 Mr. Tiedemann, and, after him, Mr. Serres, have 
 treated in a particular manner of the formation 
 
and successional developement of the several 
 parts composing the nervous system. 
 
 Of the Mode of Formation of the Nervous System. 
 
 I have no intention of entering into any dis- 
 cussion upon Encephalogejiy. My researches have 
 not been of extent sufficient to qualify me either 
 to admit or to reject the opinions promulgated 
 by M. Serres upon this subject. According to 
 this gentleman, the spinal cord, the cerebellum, 
 and the brain, are developed from the circum- 
 ference towards the centre, and not, as ana- 
 tomists had hitherto admitted, from the centre 
 towards the circumference. He tells us, that 
 there are many centres of formation, and that 
 each apparatus is composed by several pieces, 
 which are joined together, the extremities com- 
 mencing, the middles terminating, the union. 
 According to him, too *, the arteries exert a par- 
 ticular directing influence over the develope- 
 ment of the nervous system. The spinal cord, 
 he conceives to be formed under the guidance of 
 the intercostal, the cerebellum under that of the 
 vertebral, and the brain under that of the carotid 
 arteries. 
 
 The vessels of the spinal cord, he says, ap- 
 pear first, and the outline of this part is soonest 
 * Tom i. p. 568, et seq. 
 
17 
 
 apparent. The common carotids appear next, 
 and then the internal vessels of that name, which 
 are distributed to the crura or legs of the brain, 
 and to the bodies called quadrigeminal, and these 
 are now evolved. The vertebral arteries reach 
 the cranium last, and the cerebellum is the latest 
 formed of all the nervous masses. 
 
 “ The brain,” he states, “ is developed from 
 before backwards, and the cerebellum from be- 
 hind forwards, according to the direction of the 
 blood-vessels. From this it comes that the cal- 
 lous body is evolved from behind forwards, as the 
 arteria callosa gradually appears.” 
 
 I intend in another place to cite M. Serres’s 
 notions upon the formation of some particular 
 apparatuses. Here I only observe that he dif- 
 fers from M. Tiedemann upon a very principal 
 point ; whilst M. Serres proclaims a successive 
 development from the circumference towards the 
 centre, M. Tiedemann publishes the reverse of 
 this as the truth. I also confess that a great 
 number of M. Serres’s opinions appear to me 
 little probable. Hr. Baron* lately shewed the 
 body of an hydrocephalic child to the Academy 
 of Medicine in Paris, and proved that though the 
 carotid arteries existed, the anterior cerebral 
 lobes were wanting. M. Serres had made too 
 hastily a contrary report upon this very case to 
 * Bulletin des Sciences Mcdicales, Juin, 1825, p. 175. 
 
 c 
 
18 
 
 the Philomathic Society the day before Dr. Baron 
 made the dissection. 
 
 In recognising the whole importance of ence- 
 phalogeny, or the doctrine of cerebral formation, 
 it still appears to me that its laws cannot be at 
 variance with those that may be demonstrated in 
 the brain when it has arrived at maturity of 
 growth. I farther opine, that conclusions drawn 
 from the structure of the adult brain, are to be 
 preferred to such as are founded on it in its em- 
 bryotic state. I shall, in more places than one, 
 have occasion to refer to this argument, and es- 
 pecially when I come to treat of the anterior 
 commissure and callous body, to the end that 
 I may rectify the erroneous opinions promulgated 
 by M. Tiedemann. My great and sole object is 
 to know the structure of the brain, such as it may 
 be demonstrated in harmony with physiology and 
 pathology. 
 
 Of the general Form of the Nervous System. 
 
 The form of the nervous system, it may be 
 conceived, varies according to the radiated, glo- 
 bular, or elongated configuration of the ani- 
 mal body, of which it is a constituent. It can- 
 not be alike in the star-fish, worm, and cater- 
 pillar. (PI. i. fig. 1.) Generally then, and even 
 as its particular parts are concerned, the ner- 
 
19 
 
 vous system exhibits the greatest varieties of 
 form. 
 
 Its masses* too, occur aggregated, as in the 
 skull, and spinal canal, or in the form of nerves 
 properly so called, or collected into knots differ- 
 ing in form, size, consistency, and colour, and en- 
 titled ganglions. Nerves frequently emanate from 
 distant and opposite sources to unite, anastomose, 
 or twine together, and then to separate and run 
 off in different directions. This is the particu- 
 lar arrangement to which the term plexus is ap- 
 plied. Ganglions and plexuses often form an in- 
 tricate tissue together. 
 
 Of the Structure and Use of Ganglions. 
 
 Ganglions are bodies composed of the two 
 nervous substances : the white or fibrous, and 
 the gelatinous or pulpy, into which the first is 
 plunged. The pulpy matter of the ganglions is 
 commonly of a gray colour, of different degrees 
 of intensity ; sometimes, however, it has a 
 yellowish, a reddish, or a whitish cast ; it is 
 easily distinguishable from the nervous filaments 
 which it surrounds. The fibres of the white 
 substance, the second element of the ganglions, 
 anastomose repeatedly ; they also cross each 
 other frequently, sometimes in every direction, 
 or in their course parallel with that of the nerve 
 upon which the ganglion is formed. Ganglions 
 
 C 2 
 
20 
 
 of this last kind are commonly oval-shaped, but 
 those in which several nerves meet and inoscu- 
 culate, have for the most part very irregular 
 forms. 
 
 Anatomists have always entertained very dif- 
 ferent opinions upon the uses of the ganglions. 
 Some, with Willis, have ascribed to them the 
 secretion of what they style vital spirits ; others, 
 with Yieussens, conceive them destined to se- 
 parate and to strengthen the nervous fibres ; 
 many of the moderns again, Bichat, Reil, and 
 others, think with Johnstone, that they serve to 
 isolate from the influence of the brain the parts 
 which receive their nerves from them. The latter 
 authors divide the nervous systems into two parts • 
 a cerebral and a ganglionary. 
 
 The theory of vital spirits is now forgotten. 
 The ganglions are also proved to do more than 
 merely separate or direct the nervous filaments, 
 as Meckel the elder, Zinn, Scarpa, and others, 
 have supposed. “ A glance,” says Bichat*, “ en- 
 ables us to discover the greatest differences 
 among them, (the ganglions.) There is evi- 
 dently as great a distinction between the gan- 
 glions and the nerves that issue from them, as 
 there is between the cerebral nerves and the 
 brain itself. There is difference of consistency and 
 other outward qualities, and there is difference of 
 properties. Were the nerves that come from the 
 * Anatomie Generate, T. 1. 
 
21 
 
 spinal cord merely unravelled in their passage 
 through the ganglions, this would be but a differ- 
 ence of form, not of nature, and their properties, 
 therefore, would remain the same. Why has not 
 nature placed ganglions on the nerves of the 
 limbs as on those of internal parts? If there be 
 only a resolution of nerves into finer filaments irr 
 ganglions, why is there no constant proportion 
 between the fibres that enter on one side, and 
 those that issue from the other? Did the nerve 
 that penetrates the superior cervical ganglion 
 from above expand in its interior, and having re- 
 united its filaments form the cord that issues from 
 below, it ought evidently to be of precisely the 
 same size at its exit as at its entrance. Such a re- 
 lation, indeed, between the nerves of the oppo- 
 site extremities of ganglions, ought to be quite 
 general. But a very cursory examination shews 
 that a contrary disposition almost invariably ob- 
 tains. The size of the ganglions should be re- 
 lative to that of the nerves, whose expanded 
 fibres are said to compose them Why then are 
 the intercostal ganglions so small, and the trunks 
 which unite, or rather, to use the common phrase, 
 originate, and then leave them so large ? And 
 why, on the contrary, is the superior cervical 
 ganglion so voluminous, and its nervous branches 
 so minute ? How can the frequent interruptions 
 among the ganglions in the human kind, which 
 in a host of animals are quite regular, be ex- 
 plained, if the nervous filaments which enter 
 
22 
 
 be continuous with those which issue from them ? 
 How comes it that the ganglions and their nerves 
 bear no exact proportion to the cerebral nerves, 
 if the latter give them birth or expand in them ? 
 Why, in fine, has not the pain, that is transmitted 
 by both kinds of nerves, the same character ?” 
 Scemmerring has made reflections very similar 
 to these of Bichat. 
 
 Notwithstanding all this, the opinion in regard 
 to the use of the ganglions, which Johnstone, 
 Bichat, and Reil entertained, and which others 
 have adopted from them, is by no means exact. 
 They do not interrupt the reciprocal influence of 
 the brain and nerves of the spinal cord, nor of 
 the brain and viscera of the chest and belly, 
 either in the healthy or pathological state of the 
 body. They most certainly do not prevent im- 
 pressions made on parts supplied with nerves 
 from them, or diseased sensations of the viscera 
 from being felt. On the contrary, the ganglions 
 would appear essential to the structure of 
 nerves of sensation. They, however, abstract the 
 parts they furnish with nervous energy, from the 
 influence of the will. They also originate ner- 
 vous fibres ; and serve, farther, as points of com- 
 munication between different nerves. Lastly, as 
 the existence of a nervous fluid is not impos- 
 sible, nay, as in all likelihood such a fluid does 
 exist, the ganglions may probably aid in its se- 
 cretion or evolution, and modify its circulation or 
 distribution. 
 
23 
 
 Section II. 
 
 Division of the Masses composing the Nervous 
 System. 
 
 We have already seen, among the general con- 
 siderations, that the nervous system is not a 
 simple unit, but an aggregation of parts, that 
 originate and may exist separately, but which 
 are in intimate communication, as was required 
 on account of the influence their functions exert 
 mutually. The functions of the abdominal vis- 
 cera, for instance, act upon those of the brain, 
 and those of the brain influence digestion, circu- 
 lation, the secretion of bile, &c. The nervous 
 system, therefore, cannot be compared to a net, 
 as is sometimes done, if, by this, similarity of 
 nature in its constituent parts be implied. On 
 the contrary, as differences are evident, divisions 
 become indispensable. 
 
 But the task of determining the instruments 
 specially dedicated to particular functions, is one 
 of great difficulty. The ordinary division of the 
 nervous masses is indisputably defective. A true 
 one can only rest on the nature of the functions 
 performed. These functions are naturally sepa- 
 rated into two grand classes : vegetative, or orga- 
 nic functions, and phrenic, or functions having 
 
24 
 
 place with consciousness. The nervous masses be- 
 longing to the first of these are, in common lan- 
 guage, the great sympathetic nerve, and the gan- 
 glions and plexuses of the thorax and abdomen. 
 Bichat has divided them into a multitude of appa- 
 ratuses, individually necessary to the offices of the 
 particular viscera. This division is, in my appre- 
 hension, founded in nature. I regard the nervous 
 masses of vegetative life as independent of those 
 of phrenic life, in as far as their existence is 
 concerned. I also incline to admit as many dif 
 ferent kinds of nerves as ' different vegetative 
 functions ; I farther recognise their communica- 
 tions among themselves, and with the masses of 
 the phrenic functions. 
 
 The nervous masses of vegetative life are very 
 simple in the lower tribes of beings ; they are 
 more numerous as we mount in the scale, and as 
 the functions of vegetative life become compli- 
 cated. Their general arrangement, as was to be 
 expected, varies according to the form and dis- 
 position of the viscera in species and individuals. 
 If visceral functions, locomotion, and manifesta- 
 tions of sensibility be united, it is also conceiv- 
 able that to separate the peculiar nerves of these 
 dissimilar operations from each other, w T ould be 
 next to impossible. This consideration shews 
 why some anatomists have compared the nerves 
 of the caterpillar and worm to the great sympa- 
 thetic; whilst others have likened them to the 
 
25 
 
 intervertebral ganglions, or to the spinal cord 
 itself. 
 
 In the vertebral classes of animals, and espe- 
 cially in the mammalia, the nervous masses are 
 distinctly separated, first, into those of vegetative 
 life, and, second, into those of phrenic functions. 
 Each of these may farther be subdivided into 
 two parts : the first into nerves of viscera, or, as 
 M. de Blainville * expresses himself, into a vis- 
 ceral portion, and into nerves of communication ; 
 that is, an apparatus which establishes sympathy 
 among the visceral nerves mutually, and be- 
 tween these and the nervous masses of the ex- 
 ternal senses, and of the affective and intellec- 
 tual functions. 
 
 The second, or nervous masses of phrenic life, 
 again, are commonly divided into the brain, pro- 
 perly so called, the cerebellum, medulla oblon- 
 gata, and spinal cord, together with the nerves 
 of these four parts. 
 
 M. de Blainville ranges the nervous masses of 
 phrenic life under two titles : the one he styles 
 Central, the other Ganglionary . “ The first, or 
 
 central,” says he f , “ is susceptible of three de- 
 grees of development; is always situated above 
 the intestinal canal, begins with the oesophagus 
 or pharynx, and is prolonged, more or less 
 
 * Bulletin des Sciences par la Societe Philomatique de Paris, 
 1821, MarsetAvril. 
 
 t Op. cit. p. 44. 
 
26 
 
 backwardly, so as to correspond to a greater or 
 smaller number of rings of the body when they 
 exist. 
 
 “ The second, or ganglionary,consists of a very 
 variable number of pairs of ganglions, disposed 
 in a slightly different manner on each side of the 
 first. 
 
 “ The central portion is always composed of 
 two similar halves, situated, the one to the right, 
 the other to the left, and more or less inti- 
 mately united, or drawn together by means of 
 the peculiar apparatus, styled commissure. It is 
 divided into two rigorously similar portions : a ver- 
 tebral and a cephalic, included, as their titles im- 
 ply, the one in the vertebral canal, the other in 
 the cranium. Both contain gray and white sub- 
 stance, and longitudinal and transverse commis- 
 sures. 
 
 “ The cephalic portion consists, 1st, of an in- 
 ferior bundle called pyramidal, which passes un- 
 der the annular protuberance, continues long dis- 
 tinct from the cerebral peduncles, and runs to 
 terminate in the anterior, or olfactory lobe, of the 
 brain. 2d. Of a superior bundle, which con- 
 tinues, in the first place, under the name of pro- 
 longation of the quadrigeminal bodies, to the 
 cerebellum, and running on the outer sides of 
 the internal geniculated bodies, is lost on the 
 hemispheres ; and, in the second, of a deep 
 bundle, which may be followed to the mammil- 
 
27 
 
 lary bodies, and from thence into the optic tha- 
 lami. The bundles named peduncles of the 
 pineal gland, which are expended on the optic 
 thalamus, are also to be regarded as belonging to 
 this cephalic portion.” 
 
 The same author subdivides his second or 
 ganglionary portion into ganglions without, and 
 ganglions with, external apparatus. Among the 
 former he reckons the olfactory masses, the hemi- 
 spheres properly so called, the quadrigeminal 
 bodies, and the cerebellum. The olfactory nerve, 
 according to him, is a cerebral mass, in which 
 his inferior central bundle terminates. The he- 
 mispheres, he conceives, form another ganglion, 
 having no external apparatus, but one transverse, 
 (the callous body,) and two longitudinal commis- 
 sures (the peduncles of the brain and the fornix). 
 It is to this ganglion that the convolutions be- 
 long. He farther regards the striated bodies as ap- 
 pertaining to the convolutions, but remarks that, 
 for certain, their fibres do not originate there 
 to go to the hemispheres. The quadrigeminal 
 bodies are the third, and the cerebellum the 
 fourth, ganglion, without external apparatus. 
 
 The title, visceral part of the nervous system, ap- 
 pears to me well chosen, but I do not think that 
 the division into central and ganglionary parts, 
 or the other subdivisions proposed, deserve the 
 same approval. 
 
 In the first place, I cannot see that they are 
 
28 
 
 based on anatomical observation ; I do not be- 
 lieve, for instance, that M. de Blainville can de- 
 monstrate the continuation of the inferior bundle, 
 or pyramidal body, into the olfactory nerve, nor 
 that he can trace what he calls the deep bundle 
 ( faisceau profond ) of his central portion into 
 the mammillary bodies. Neither do I think that 
 his divisions and subdivisions of the nervous 
 mass pertaining to phrenic life, are consistent 
 with physiological facts; but this in anatomical 
 classification is quite essential : it is even acknow- 
 ledged by M. de Blainville himself as its basis. 
 “ We ought,” says he *, “ to consider the ner- 
 vous system as subdivided into as many parts as 
 there are grand functions performed by the ani- 
 mal body.” 
 
 According to the ideas of M. Desmoulins, the 
 parts which constitute the complete cerebro-spinal 
 system of mammalia, are — 1st, the spinal cord ; 
 2d, the cerebellum, which is itself composed of 
 three parts ; 3d, the optic lobes, or quadrigemi- 
 nal bodies ; 4th, the lobes of the brain ; 5th, the 
 olfactory lobes. These five parts are admitted by 
 M. Desmoulins not to be always complete in the 
 other classes of vertebral animals, and also to be 
 wanting, individually, without detriment to the 
 rest. The sturgeon, lamprey, frog, and some 
 other creatures, have, he says, no cerebellum ; 
 the skate and shark no cerebral lobes ; many 
 
 * Op. cit. p. 40. 
 
29 
 
 bony fishes no olfactory lobes ; in short, he 
 concludes, that generally speaking, the notion 
 concerning the unity of the nervous system is a 
 chimera. 
 
 In opposition to M. Demoulins’s views, Dr. 
 Bailly has maintained that every vertebra, or every 
 segment, through the whole length of the animal 
 body, contains the same nervous elements ; that 
 belonging to each of the vertebrae of the head and 
 spine, there are nerves of sensation, of motion, of 
 digestion, and of an intellectual system, charged 
 with the task of appreciating the impressions 
 communicated by the others, and of producing 
 determinations. 
 
 In my apprehension, the cerebro-spinal system 
 is not a simple unit, but a compound of many 
 distinct apparatuses, each of which has particular 
 functions, which, being taken together, constitute 
 phrenic life. The several instruments are formed 
 after a general plan, but the physical qualities, as 
 the density, form, size, and colour, of all, indivi- 
 dually, differ not only in the classes and in the 
 species, but also in the members composing each 
 kind ; the number of particular organs is likewise 
 greater or smaller in the classes and species, ac- 
 cording to the amount of the primary functions, 
 or faculties; lastly, each of the apparatuses is 
 simple, or it is compound. 
 
 No one, however, can be said to be perfectly 
 simple ; each is, at least, double, or one of a pair. 
 
30 
 
 The organs of motion and of touch are evi- 
 dently multiplied. 
 
 It is essential, in dividing and subdividing the 
 parts of which the cerebro-spinal system is com- 
 posed, to keep in harmony with physiology and 
 pathology, and to distinguish between what is 
 common to all, and what is peculiar to each of 
 them. The first grand division must embrace the 
 instruments of motion, and of the five external 
 senses; the second comprise the organs of the 
 affective and intellectual functions. 
 
 I think they do wrong who confound the spi- 
 nal cord with the cerebral masses, and designate 
 both by a common title, such as encephalon or brain. 
 It is long since Dr. Gall and I pointed out this 
 error, but it is still very generally sanctioned, by 
 the French Academy of Sciences, for instance, so 
 late as 1820 , its prize having been accorded to the 
 memoir of M. Serres upon the following title. — 
 “ Donner une description comparee du cerveau 
 dans les quatre classes des animaux vertebres, 
 et particulierement dans ceux des reptiles et des 
 poissons, cherchant a determiner l'analogie des 
 differentes parties de cet organe, ou marquant 
 soigneusement les changes des formes et des pro- 
 portions eprouvees, et suivant aussi profondement 
 que possible les racines des nerfs cerebreaux/’ 
 Here the brain and its nerves only are evidently 
 spoken of. M. Serres, however, deemed it pro- 
 per to consider the nervous mass of the spine as 
 
SI 
 
 well as of the cranium, and he has designated 
 these two systems by the same name, without 
 any objection being made by the Academy to 
 this arrangement. 
 
 Let us turn to the facts that prove the brain 
 and the spinal cord to be perfectly distinct and 
 independent of each other. These facts are ana- 
 tomical, physiological, and pathological. I here 
 assume as an established point, that the functions 
 of the spinal cord differ entirely from those of the 
 brain. The development and demonstration of 
 this truth belong to physiology. I have, accord- 
 ingly, examined it particularly in my work on 
 Phrenology. Physiological experiments and pa- 
 thological facts tend equally to show that the 
 brain and spinal cord are masses possessed of 
 distinct functions that cannot be confounded. 
 This volume being destined solely to the discus- 
 sion of anatomical views, I shall, at present, 
 confine myself to such evidence as anatomy affords 
 of the mutual independence of each of the nervous 
 masses mentioned. 
 
 And first — all that has been said, in a general 
 way, upon the origin of the nerves, and their 
 existence, independently of the brain, applies 
 particularly in the case of the spinal cord. The 
 spinal cord sometimes exists in part, sometimes 
 entirely, when the brain is altogether wanting. 
 If, to this, it be objected that the brain had been 
 removed by absorption, the answer I have given 
 
82 
 
 to the same proposition, in reference to the nerves 
 in general, must be repeated here. There is, 
 also, one, and but one, case on record, in which 
 the brain existed, without the spinal cord*. It 
 occurred in a child whose head or heads are pre- 
 served in the Hunterian Museum, in London ; 
 this child was born with one skull placed vertically 
 upon another. Each of these contained a brain 
 invested with its usual membranes ; the dura 
 mater of each brain adhered closely to that of 
 the other, and both were supplied by blood- 
 vessels issuing from common trunks. Parts, con- 
 sequently, as the brain and spinal cord that exist, 
 or not, independently of each other, cannot con- 
 stitute one and the same apparatus. 
 
 2. The nervous masses of the spinal canal and 
 cranium bear no regular proportion to each other. 
 Man, with liis voluminous brain, has a smaller 
 spinal cord than the ox or horse, whose brain is 
 so much less. Bartholin in former times, and 
 Scemmerring in our own days, made this remark ; 
 nevertheless, they both continued to speak of the 
 spinal cord as a process or continuation of the 
 brain. 
 
 3. The spinal cord is well known not to de- 
 crease in size as it descends in the vertebral 
 canal, and as it sends off nerves. Its volume is 
 even augmented, where its nerves are largest and 
 
 * See Philosoph. Trans, for 1790, March 25th, and for 179S, 
 Dec. 13 th. 
 
S3 
 
 most numerous; this is obvious, especially to- 
 wards its sacral end, as may be seen by turning to 
 PI. i. fig. 2, where this part of the spinal cord of 
 a fowl is represented; and yet the spinal cord is 
 commonly considered as a prolongation of the 
 white substance of the brain and cerebellum ! 
 
 4*. The direction of its nerves, especially in the 
 mammalia, proves to a certainty, that the spinal 
 cord is not a continuation of the nervous mass of 
 the cranium. Every pair of spinal nerves is made 
 up by several bundles: (PI. i. fig. 3; a part of the 
 spinal cord of a calf ;) some of these issue from 
 below, and run upwardly; others come from 
 above, and proceed down and outwardly. Now 
 it would be absurd to suppose that these bundles 
 were continued, or derived either from the lower 
 or upper extremity of the spinal cord. They un- 
 doubtedly originate at the place whence they 
 issue individually. 
 
 In regard to the fifth, sixth, seventh, and other 
 pairs of nerves, styled cerebral (PI. vi. fig. 1), 
 their direction also shows that they do not come 
 either from the brain or cerebellum. Santorini, 
 when speaking of the course of the fifth pair, 
 remarks, that after descending from the brain, it 
 turns back and runs upwards ; and he adds — “ if 
 it do not probably come from below, entirely 
 like the accessory nerve.” 
 
 The proofs, confirmatory of the mutual inde- 
 pendence of the spinal cord aud hemispheres of 
 
 D 
 
34 
 
 the brain and cerebellum, serve also to demon- 
 strate the propriety of separating the nerves, 
 styled cerebral, from the brain itself. The evi- 
 dence in this, as in the other case, is anatomical, 
 physiological, and pathological. For the reasons 
 already given, I here rest on anatomical testimo- 
 nies alone ; for information on the others, I refer 
 to my physiological and pathological treatises*. 
 
 To proceed, then, we see monsters, occasionally, 
 born without any of the proper cerebral masses, 
 but with olfactory, optic, and acoustic nerves, 
 either severally or altogether perfect ; and on the 
 contrary, these nerves, individually, or generally, 
 have been found in a state of atrophy, whilst the 
 brain was sound and well developed in all its 
 parts. There is no proportion, whatever, between 
 the cranial nerves and the true cerebral mass. 
 Many animals have them much larger in propor- 
 tion to their brain than man. 
 
 I repeat, therefore, that I divide and subdivide 
 the nervous masses according to their offices: 
 first, into nerves of vegetative functions ; secondly, 
 of external sense, and locomotion ; lastly, of affec- 
 tive and intellectual operations : these last inhere 
 in parts, which I style truly cerebral, super- 
 added to the nerves of the senses. 
 
 We shall, afterwards, see that the masses be- 
 longing to the last-named class of functions require 
 
 * Phrenology ; or, the Doctrine of the Mind; Lond. 1S25. 
 Observations on Insanity ; Lond, 1816. 
 
35 
 
 subdividing into instruments of particular func- 
 tions, after the manner of the external senses. 
 
 This principle of the plurality of the nervous 
 apparatuses is the basis of these anatomical con- 
 siderations, and is indispensable to the physiolo- 
 gical researches in which Dr. Gall and I have so 
 long been engaged. It has been, and is still, 
 contested, and at the same time it is brought for- 
 ward as new. A reference, however, to the date 
 and matter of our publications, will assign it to 
 those who can claim it by right. The general 
 idea of a plurality of organs, indeed, must be 
 allowed to be very ancient, and not the discovery 
 of any modern author ; before Dr. Gall appeared, 
 however, none of the cerebral functions had been 
 specified, and before our combined investigations 
 were made public, the structure of no special 
 apparatus had been demonstrated ; for the parts of 
 the encephalon that bear distinguishing titles, do 
 not, by any means, constitute particular organs. 
 The special determination, as well anatomical as 
 physiological, consequently, belongs to Dr, Gall 
 and myself. 
 
 D 2 
 
36 
 
 Section III. 
 
 Of the Nervous Masses of Voluntary Motion and 
 of the External Seiises. 
 
 These masses include the spinal cord, with its 
 nerves, and the nerves of the head, distinguished 
 by the title, cerebral nerves. They may, therefore, 
 be divided and spoken of as spinal or vertebral, and 
 as cranial. The former, principally contained in 
 the canal of the vertebral column, are more con- 
 siderable in size, and are entirely destined to the 
 functions of feeling and voluntary motion ; the 
 latter are less voluminous, but besides nerves of 
 voluntary motion and of feeling, they include 
 nerves of taste, hearing, sight, and smell. 
 
 Anatomists have, at all times, separated the 
 nerves of four of the senses, to wit — smell, taste, 
 sight, and hearing, from those appropriated to 
 feeling; they have also regarded the third, fourth, 
 and sixth pairs of nerves as especially destined 
 to motion ; but they have confounded all the other 
 trunks of the medulla oblongata and spinal cord, 
 and supposed the whole to pertain to feeling. 
 
 It is long since I maintained the necessity of 
 subdividing these nerves, and of admitting se- 
 parate fibres for the functions of touch and 
 
37 
 
 of motion. My opinion was founded on facts, 
 and reasonings anatomical, physiological, and 
 pathological. It was long ago remarked that feel- 
 ing and voluntary motion were not always im- 
 paired or annihilated simultaneously ; sometimes 
 the one, sometimes the other of these functions 
 was seen to be totally lost, whilst the other 
 remained unimpaired. The conclusion then fol- 
 lowed, and it had already been seized by Erasi- 
 stratus of Alexandria, that there were nerves of 
 motion, and nerves of feeling. Pathological facts, 
 therefore, first fixed the attention of physicians 
 on this point, as they also gave the first idea of 
 a decussation of nervous fibres in the brain, and 
 of the peculiar structure of the convolutions. 
 
 To the above, some have replied that the ad- 
 mission of two sorts of nerves to explain the 
 isolated lesion, whether of voluntary motion or 
 of feeling, was unnecessary ; the loss of motion, 
 they say, is consequent on a minor degree of 
 cerebral affection, the destruction of feeling on 
 disease of a graver and more extensive description. 
 
 This objection is purely speculative, and is to- 
 tally unsupported by experience. To make it even 
 plausible, it should surely be capable of stand- 
 ing the test of physiological proofs in the healthy 
 state, that is to say, sensibility and volition should 
 be shown to be mere degrees of the same power, 
 volition being the lower of the two ; but obser- 
 vation is very far from confirming such an opinion. 
 
38 
 
 Physiology, and analogy, in reference to the 
 other senses, appear to determine feeling as a 
 function entirely distinct from voluntary motion, 
 and to prove each of these functions as manifested 
 by the medium of a special organ or nerve. The 
 functions of touch are active and passive, like 
 those of the other external senses. The muscles 
 are called into action, would the internal faculties 
 employ any of the senses to cognize impressions 
 from without. They aid touch in feeling, as they 
 assist sight in looking, hearing in listening, and 
 the olfactory nerves in smelling. The nerves of 
 voluntary motion, i. e., of its organs, the muscles, 
 cannot propagate impressions of touch, nor the 
 nerves of the skin those of motion. The impres- 
 sions propagated by the nerves of motion come 
 from within, as those transmitted by the nerves 
 of feeling are derived from without. The muscles, 
 alone, produce sensations of fatigue or weariness, 
 and these have no relation to the nerves of feeling • 
 
 O 
 
 we may be excessively fatigued, and at the same 
 time, have the sense of touch extremely vigorous. 
 
 Physiological and pathological facts being strik- 
 ingly and universally favourable to the idea of 
 distinct nerves of feeling and motion, and four of 
 the senses being evidently provided with peculiar 
 nervous apparatuses, I have always maintained the 
 probability of the same law obtaining, in regard 
 to the fifth, and even invited anatomists to use 
 their endeavours to verify the point, and to de- 
 
39 
 
 monstrate the muscular as distinct from the cuti- 
 cular nerves. 
 
 To the above notion, it has been objected, that 
 the nerves of feeling and of motion issue together 
 from the spinal cord, and, as a consequence of 
 this, that the nature of every fibre, of the same 
 pair, must be essentially the same. To this 
 I always answered that the objection is neither 
 valid on the strength of the fact, nor on that of 
 the inference from it. For the spinal pairs are 
 composed of two roots, the one dorsal, the other 
 abdominal ; and further, each root is, itself, com- 
 posed of many bundles. I also stated that this 
 structure was less conspicuous in the fifth cranial 
 nerve than in the spinal pairs ; but that, never- 
 theless, the difference of its bundles, and their 
 dissimilar functions, were recognised. One, all 
 allow, is appropriated to taste, whilst the rest 
 belong to sensation in general. In conformity 
 with the above view, the glossopharyngeal has 
 always appeared to me destined to the third sort 
 of the lingual functions, that is, to general feeling. 
 
 The above ideas were published in my English 
 work, “The Physiognomical System in 1815; 
 and in 1818, in my French book, entitled, 
 “ Phrenologie j\” In all the courses of lectures 
 I have delivered since these works issued from 
 the press, I have broached similar ideas, and en- 
 couraged those of my auditors, whom opportunity 
 
 * First and Second Edition, p. 23. t Op. cit. p. 236. 
 
40 
 
 favoured, to enter on the inquiry, and to endea- 
 vour to trace the nervous fibres from their peri- 
 pheral expansions to their origin in the spinal 
 cord. 
 
 The subject has, indeed, been advanced by 
 the labours of Messrs. C. Bell and Masrenclie. 
 
 o 
 
 Mr. Bell has recognised a difference between the 
 nerves of sensation in general and those of re- 
 spiration *. He admits, in the first instance, that 
 every apparatus operating a single function, is 
 provided with but one nerve ; that parts which 
 receive two nerves, whose origins are differ- 
 ent, perform two functions ; and that organs, 
 whose nerves are derived from several sources, 
 effect various, and not merely stronger, func- 
 tions of one specific kind. He regards as respi- 
 ratory nerves the pneumogastric, with its vocal 
 branch ; the glossopharyngeal ; the accessory of 
 Willis ; the facial ; the hypoglossal, and the dia- 
 phragmatic (the phrenic). 
 
 Mr. Bell has further established a difference 
 in function between the facial nerve, (portio 
 dura of the seventh pair,) and the branches of 
 the fifth pair. He has proved by his experiments, 
 that the facial gives no impression of pain when 
 it is cut, but that the effect of the operation is to 
 abstract the parts upon which it is ramified from 
 
 * On the Nerves ; giving an Account of some Experiments 
 on their Structure and Functions. Read before the Royal Society 
 of London, July 12, 1S20. 
 
41 
 
 the influence of the respiratory motions. Lesions, 
 on the contrary, of the fifth pair, produce pain, 
 and the parts it supplies become insensible, when 
 its branches are cut across. He still further 
 cites cases, in which sensibility remained unim- 
 paired, although the side of the face was com- 
 pletely paralyzed in its movements. 
 
 Mr. Bell has given his attention more particu- 
 larly to the influence exerted by the facial nerve 
 on respiration, and by the function of respiration 
 on parts that receive branches from this source. 
 The facial he styles, in particular, nerve of ex- 
 pression. Being a nerve of motion, however, it 
 may, independently of any additional considera- 
 tion, be entitled a nerve of expression. That it 
 may be influenced by respiration, no one will 
 probably deny, but it may also unquestionably 
 act independently of this function. Mr. Bell, 
 indeed, has not in this instance adhered rigo- 
 rously to his principle recognised in theory, and 
 mentioned above, viz., that no nerve performs 
 two functions-— the facial, on his own data, can 
 only be a nerve of one kind of function, 
 
 I chanced very lately to see a case where the 
 voluntary motion of the right side of the face was 
 lost, whilst its sensibility remained ; both feeling 
 and motion on the left side were intact ; the 
 movements of the tongue were also natural ; but 
 if the person attempted to spit, the saliva was 
 
42 
 
 always thrown to the right by the action of 
 the left and healthy half of the cheeks and lips. 
 
 M. Serres gives the case of a young man, who 
 was constitutionally epileptic, and troubled with 
 a slight ophthalmy in the right eye. The latter 
 affection increased gradually, the cornea became 
 opaque, the sight decayed more and more, and 
 was, in fine, entirely destroyed ; the other organs 
 of sense and motion on the same side were suc- 
 cessively paralyzed ; the eye, eye-lid, nostril, 
 and half of the tongue, lost their powers, whilst 
 on the left they remained in a state of perfect 
 integrity. This patient died. On dissection, 
 there was found, first, an organic change of the 
 ganglion of the fifth pair; it Avas enlarged, of a 
 yellow colour, and vascular beloAV ; second, a 
 conversion of the nerve itself, at its insertion into 
 the annular protuberance, into a yellow gelati- 
 nous-looking matter, similar to the ganglion, and 
 penetrating, in little processes, the substance of 
 the protuberances in the direction of the nervous 
 insertions. The muscular branches of the nerve, 
 however, Avere found healthy on the othenvise 
 affected side ; the process of mastication, there- 
 fore, had never been injured. 
 
 The difference in the functions of the facial 
 nerve and fifth pair, affords a new proof of the 
 distinction betAveen nerves of feeling and nerves 
 of motion. 
 
43 
 
 M. Magendie * found that sensibility was de - 
 stroyed when the dorsal roots of the spinal 
 nerves were cut through, and that motion suf- 
 fered when the abdominal origins were the 
 subjects of his experiments. He also observed 
 that the abdominal side of the spinal cord was 
 less sensible to pricking or cutting than the 
 dorsal ; but that the introduction of a probe 
 along the axis of the part did not seem to have 
 any influence either upon motion or sensation. 
 The case of a man, who died in his sixty-sixth 
 year at Charenton, seems to corroborate these 
 ideas. During the last seven years of his life 
 his organs of motion had been paralyzed, but 
 those of sensation remained uninjured ; his in- 
 tellectual faculties were almost annihilated, and 
 his excretions were all involuntary. Thus re- 
 duced, he died. On opening the body, the pyra- 
 midal and olivary bodies were found pulpy, and 
 of a dirty gray colour. The same change was 
 observed along nearly the whole of the anterior 
 surface of the spinal cord, and penetrating 
 through almost the whole thickness of the fibrous 
 bundles that compose it. The abdominal roots 
 of the spinal nerves were still visible, but their 
 consistence was much diminished. The dorsal 
 surface of the cord, on the contrary, and its in- 
 vesting membranes, were in a healthy condition. 
 
 * Journal de Physiologic Experimentale et Pathologique, 
 tom. iii. 
 
I am, however, rather inclined to question the 
 accuracy of the report in reference to the brain 
 and cerebellum, when they are stated to have 
 been in a natural state ; for I observe that the 
 skull was eburneous, and three times thicker than 
 common. Such changes of the cranium are, I 
 believe, constantly accompanied by alterations in 
 the encephalic masses. 
 
 M. Magendie also mentions a singular case, 
 observed by M. Rullier, of a man who died at 
 the age of forty-four. Up to his last hour this 
 person possessed great moral energies, strong 
 generative powers, free motion of his lower 
 limbs, and perfect sensation in his upper extre- 
 mities. The arms, however, were rigid, their 
 muscles being permanently contracted, and often 
 painful. They were rotated inwards, and 
 pressed to the sides of the body, from which they 
 could not be separated, but with some consider- 
 able effort. The fore-arms were in a state of 
 uneasy pronation, the hands flexed, and all 
 the fingers bent. On dissecting the body after 
 death, “ the spinal cord, examined with care, ap- 
 peared in its natural state, from its upper end as 
 low down as the exit of the fourth pair of cervi- 
 cal nerves. The dorsal surface of its two lower 
 thirds was also healthy, but between the por- 
 tions named, and through a space corresponding 
 to the branching of eight or nine pairs of nerves. 
 
45 
 
 (six or seven inches in extent,) there was a very 
 decided alteration. The spinal cord was there 
 so extremely soft and diffluent, that the sheath 
 formed by the dura mater seemed filled with a 
 true fluid, which, indeed, flowed upwards or 
 downwards, as the body was inclined. A punc- 
 ture being made through the sheath, a consider- 
 able quantity of fluid instantly escaped.” 
 
 The last passage of this report, in reference to 
 the puncture of the dura mater, does not seem 
 to me very exact ; because in a preceding sen- 
 tence it is stated, that “ below the part of the 
 arachnoid, which adhered to the spinal cord, 
 its proper membrane seemed charged with a 
 great number of vessels, both arteries and veins, 
 all loaded with blood.” This description leads 
 me to conceive that the dura mater was slit 
 lengthwise, and separated from the arachnoid 
 and proper investing membrane of the spinal 
 cord. If this were not so, the dura mater must 
 then have adhered to the two inner membranes, 
 and the puncture, consequently, could not have 
 been confined to the first alone. I'am confirmed in 
 this opinion by what M. Magendie says, when 
 he adds, that the man had probably lost a good 
 third of the nervous matter of the spinal cord, 
 that the communication between its cervical and 
 dorsal parts was, so to say, maintained by the 
 membrane only ; for there seemed to remain no 
 more of its entire thickness than a layer of white 
 
46 
 
 substance, scarcely two lines broad, and pro- 
 bably altered in its structure. 
 
 The state of the nervous pairs, corresponding 
 to the part of the spinal cord that was destroyed, 
 ought also, in my opinion, to have been men- 
 tioned. Information on the structure of the re- 
 maining thin layer of nervous substance would 
 likewise have been interesting ; was it composed 
 of longitudinal fibres, serving as a means of 
 communication between the upper and lower 
 portions of the spinal cord ? Is it at all probable, 
 that this office was performed by the sheath as 
 stated ? If it was, the sheath, most certainly, was 
 neither the arachnoid nor the dura mater. The 
 nevrilema, that envelopes the pulpy nervous sub- 
 stance immediately, could alone execute such an 
 office. 
 
 M. Boulay, jun., veterinary surgeon at Paris, 
 relates the case of a horse, whose hind legs 
 were completely paralyzed, whilst their sensibi- 
 lity was extreme. On opening his body, the whole 
 of the lower part of the spinal cord was found 
 soft and diffluent. There were no traces of 
 change in the superior portion. The nervous 
 substance of the lumbar and sacral pairs of nerves 
 was but little consistent, and their sheaths were 
 red and inflamed. 
 
 The distinction of the nervous roots into dor- 
 sal and abdominal, accords with the two sorts of 
 function performed by the spinal mass. This 
 
47 
 
 subject, however, still requires elucidation ; for 
 M. Magendie remarks, that “ when the posterior 
 roots, covered even with their sheaths, are irri- 
 tated, signs of extreme suffering are manifested ; 
 and, what is particularly deserving of notice, 
 contractions of those muscles that receive nerves 
 from below the place so irritated are excited ; 
 these contractions, too, only occur on the side 
 of the body the nervous fibres of which are 
 pricked.” According to the observations of the 
 same author, the abdominal surface of the spinal 
 cord is not altogether insensible when irritated. 
 The communication between the spinal cord and 
 the nerves of the vegetative functions is also 
 known to be established by means of fibres, 
 which communicate directly with the abdominal 
 roots of the spinal nerves ; nevertheless, the will 
 has no influence over the functions of the vis- 
 cera. Moreover, the fibres of the dorsal roots 
 are evidently larger than those of the abdominal ; 
 both are in proportion to the volume of the parts 
 to which they are distributed, and both send off 
 branches that run into muscles. It is improbable, 
 therefore, that the dorsal roots are solely des- 
 tined to general sensation. Neither does it seem 
 to me at all likely, that the spinal cord and its 
 nerves are mere conductors of sensation, and of 
 volition in reference to motion. I rather con- 
 ceive that they aid in maintaining the powers of 
 those parts to which they are distributed ; for in- 
 
48 
 
 stance, that the muscles, or instruments of mo- 
 tion, acquire their power, in part, through the in- 
 fluence of their nerves, whilst the will to make 
 the muscles act resides in the brain. Thus I do 
 not believe that the only office of the spinal cord, 
 with its nervous roots, is to establish a commu- 
 nication between external impressions and the 
 brain, and between the brain and the instruments 
 of motion — the muscles. To me it seems pro- 
 bable, that a very small part of the spinal cord 
 suffices for these purposes ; the particular por- 
 tion, or organ, however, cannot, in the present 
 state of our knowledge, be specified. The ex- 
 periments of M. Magendie prove the abdominal 
 roots to include the conductors of volition ; but 
 as each of these is composed of two halves, the 
 one superior, the other inferior, and, in man, of 
 two distinct cords, it would be interesting to re- 
 peat and to extend the experiments, and by 
 cutting the halves separately, to ascertain whether 
 both propagate the dictates of the will ; or if 
 this task is limited to one, to that, namely, 
 which does not communicate with the inter- 
 costal nerves. The ganglions of the intercostal 
 nerves, as well as those of the dorsal roots of 
 the spinal cord, may possibly prevent the will 
 influencing the functions of the parts, to which 
 these nerves are distributed. 
 
 The set of experiments instituted by Dr. Bel- 
 lingeri, and detailed in a Memoir read before the 
 
49 
 
 Royal Academy of Sciences at Turin, in Fe- 
 bruary, 1824, do not tend to throw any new light 
 on this interesting subject. They confirm the 
 general idea upon the presence of separate 
 nerves of sensation and of motion in the spinal 
 cord ; but they, farther, accord motion to the 
 nerves that issue from the dorsal roots. Dr. Bel- 
 lingeri says, his experiments prove, 1st, that the 
 posterior roots of the lumbar and sacral nerves 
 produce the motions of extension in the lower 
 extremities ; 2nd, that the posterior roots alone 
 preside over sensation ; 3rd, that the anterior 
 roots produce the motions of flexion in the sa- 
 cral extremities, and do not aid in perceiving 
 external impressions ; 4th, that the posterior 
 bundles of the spinal cord preside over the mo- 
 tions of extension of the inferior extremities, 
 and have no connexion with perceptions of touch ; 
 5th, that the white substance of the spinal cord, 
 and the nervous fibres that arise from it, are ap- 
 propriated to motion ; and, 6thly, that the gray 
 substance of the cord and the nervous fibres that 
 spring from it, belong to sensation. 
 
 I have copied these statements from the 
 ‘ Revue Encyclopedique,’ vol. xxi. p. 723. The 
 ‘Bulletin des Sciences Medicales,’ for June, 1825, 
 also records these experiments, the inferences 
 from which are in opposition to those deduced by 
 M. Magendie from his own. 
 
 I do not think with Dr. Bellingeri, that the 
 
 E 
 
50 
 
 vertebral nerves can be divided into those which 
 come from the white, and those which issue from 
 the gray, substance of the spinal cord ; because, 
 on examining the structure of this part and its 
 nerves, I find that the origins of the latter inva- 
 riably present the same appearance ; they are 
 universally implanted, as it were, into the gray 
 substance of the cord. 
 
 From all I have said, it must be evident that I 
 do not doubt the presence of two distinct species 
 of nerves among those that issue from the spinal 
 cord in particular, one propagating impressions 
 from without, the other conveying the dictates 
 of volition, in regard to motion, from within. 
 This subject, however, is obviously involved in 
 much obscurity, and will require ulterior and 
 farther investigation to be rendered clear. 
 
 Let us now examine the structure of the ner- 
 vous mass of the spine, known under the title of 
 spinal cord, or spinal marrow. 
 
 CHAPTER I. 
 
 Of the Nervous IS lass of the Vertebral Column. 
 
 The spinal cord is found in all vertebral animals, 
 whilst in the avertebralia, such as worms, in- 
 sects, the Crustacea, and mollusca, the nerves 
 form masses, which are separate and distinct in 
 
51 
 
 the ratio of their functions. The digestive powers 
 of the avertebralia commonly predominate over 
 those of general sensibility ; and the same gan- 
 glions that supply the viscera with nerves, also 
 supply the muscles. In the vertebralia, on the 
 contrary, where sensation and motion play prin- 
 cipal parts, there are particular nervous masses 
 destined to each kind of function. 
 
 The spinal cord having always the same func- 
 tions, may be conveniently compared in the four 
 classes of vertebral animals. In all, its structure 
 is essentially the same ; modifications only are to 
 be observed. 
 
 General Considerations on the Spinal Cord of 
 Man and Animals. 
 
 The nervous mass of the spine is composed of two 
 similar halves, one on each side of the mesial plane 
 of the body. They are parted to a certain depth 
 by two longitudinal clefts, the one, of course, on 
 the dorsal, (pi. i. fig. 5,) the other on the abdo- 
 minal surface, (pi. i. fig. 4, s — s ), and united be- 
 tween these fissures by a commissure, or appara- 
 tus of union, (pi. i. fig. 6 and 7. 9- — 9-). This com- 
 missure is pierced in its interior by a canal, which 
 is more or less distinct in different animals, (pi. i. 
 fig. 8 and 9,) and is especially visible during the 
 earliest periods of life. 
 
 The canal of the spinal cord has given rise to 
 
 E 2 
 
muc h discussion, and nothing certain is even now 
 concluded in regard to it, neither as to the space 
 it occupies, nor to the mode of its formation. Be- 
 fore explaining my own views upon this point, I 
 shall quote a passage, published in the first vo- 
 lume of our large work on the “ Anatomy and 
 Physiology of the Brain and Nervous System.” 
 
 “ M. Demangeon and Messrs. Devilliers, uncle 
 and nephew, afforded us the opportunity of exa- 
 mining a case of Spina bifida, conjoined with 
 considerable hydrocephalus. From the second 
 to the fourth lumbar vertebra, the spinous pro- 
 cesses of which were wanting, there extended 
 a membraneous pouch about two inches in diame- 
 ter. .During the eighteen days which the child 
 survived its birth, a great quantity of fluid exuded 
 continually from this pouch. Having cut away 
 some of the other vertebrae, we observed no swell- 
 ing of the dura mater, neither did any fluid escape 
 when we slit open this membrane lengthwise. It 
 was only between the arachnoid and the proper 
 vascular coat, that a small quantity had accumu- 
 lated, and it communicated with the pouch. 
 
 “ The spinal cord was of its usual form. We 
 shook the head, and turned it in every direction, 
 but could perceive no communication between the 
 water collected in the ventricles of the cerebral 
 hemispheres and the spinal cord or its membranes. 
 
 “ To learn, positively, whether or not any 
 communication did exist between the pouch and 
 
53 
 
 interior of the spinal cord, we cut this across in 
 the neck ; it appeared in the usual state : on blow- 
 ing, however, through a pipe upon the transverse 
 cut, each half of the cord presented an openings 
 about the magnitude of a middle-sized goose-quill. 
 The two canals were separated by the commis- 
 sure. We could not inflate the spinal cord through 
 its entire length at once. We could only effect 
 this partially. Downwards, the air penetrated 
 freely for three inches, but there the canals were 
 no farther pervious, so that no communication 
 existed between them and the pouch. Neither 
 could we perceive that there was any fluid in the 
 canals. The pouch, itself, was formed partly by 
 the dura mater and tunica arachnoides. Its supe- 
 rior edge touched the lower extremity of the 
 spinal cord. Although we had blown into the two 
 halves of the spinal marrow in so easy and uniform 
 a manner, we still could not determine whether 
 the canals were to be considered as an effect of 
 disease or not. We, therefore, examined the 
 spines of children at the period of birth, of others 
 somewhat older, and of adults ; in all we disco- 
 vered a corresponding organization. We, however, 
 found that the canals did not expand before the 
 blow-pipe so readily in children somewhat ad- 
 vanced, and in adults, as they did in subjects in 
 the earliest infancy ; we, therefore, to show the 
 fact, prefer the bodies of newly-born children. 
 In other respects, precisely similar openings on 
 
54 
 
 each side are to be observed in all ; the interior 
 surfaces too, being always smooth. If the blow- 
 ing into the canals be continued from below until 
 as many as six or eight lines are opened, and only 
 five or six lines are cut off in succession, so that 
 the opening may be always maintained, the canals 
 may be followed into the medulla oblongata, the 
 tuber annulare, under the corpora quadrigemina, 
 through the crura cerebri, and even on to the 
 supposed optic thalami and the commencement 
 of the corpora striata. Although no opening be 
 observable into the fourth ventricle, nor into the 
 aqueduct of Sylvius, nor into any other of the ce- 
 rebral cavities, this structure, nevertheless, would 
 incline us to admit the possibility of a fluid being 
 secreted by the canals, and producing a true 
 dropsy of one or both cavities of the spinal cord. 
 
 “ Each half of the spinal cord then may be con- 
 sidered as a membrane doubled on itself, along the 
 middle line of which the gray substance, although 
 without apparent division, may, by a slight blast, 
 be separated, so as to form the sides of a canal. 
 
 “ No violent separation can here be supposed ; 
 for, in the first place, it is effected with perfect 
 ease, whilst in other situations, and even where 
 the gray substance is much softer, no disjunction 
 can be operated without the greatest difficulty. 
 Secondly, where a separation of parts is the con- 
 sequence of violence, the edges are ragged and 
 uneven ; whilst in the case cited, the surfaces are 
 
55 
 
 continuous and smooth. Thirdly, the openings 
 in the situations mentioned, are always found 
 in the same places, are perfectly equal, being 
 sometimes quite round, sometimes oval-shaped, 
 sometimes slightly angular, and running now ho- 
 rizontally, then vertically, obliquely, or in a semi- 
 circular direction, according as the curves of the 
 medulla oblongata, of the pons Varolii, of the 
 crura cerebri, of the optic thalami, or the parts 
 that surround the canal determine. If the air be 
 propelled too forcibly, the canal will burst where 
 the gray substance is the most slightly covered 
 by nerves, as at the places where the nerves issue, 
 although the tearing off of these does not, of 
 itself, give any outlet to the air.” 
 
 Since the above was written, I have seen rea- 
 son to change my opinion, and I now consider 
 the canals to be mere effects of the blowing. I 
 have produced them in birds and fishes as well 
 as in man. They are not, however, I must here 
 observe, to be confounded with the true canal of 
 the spinal cord — the canal that exists in the inte- 
 rior of the commissure or apparatus of union. 
 This is quite uniform, and is occasionally the seat 
 of disease, getting filled with serum. It is more 
 or less distinct in animals of the inferior classes, 
 and in the embryos of those of superior tribes. In 
 the human foetus, it is commonly visible during 
 the first four or five months from conception. 
 After this date it is generally, though not inva- 
 
56 
 
 riably, obliterated. This explains how its exist- 
 ence has been at one time admitted, at another 
 denied, and how, in extraordinary cases, it has 
 even been found in advanced old age, as Charles 
 Etienne, Columbus, Morgagni, Senac, Portal, 
 and other authors have observed. The canal of 
 the spinal cord appears to be analogous to the 
 aqueduct of Sylvius. 
 
 M. Serres has said that the spinal marrow in 
 young embryos consists of two cords, which unite 
 first in front and compose a gutter, but which 
 coming together, speedily get blended behind. 
 The interior of the spinal marrow is then hollow, 
 and forms a long canal, which is gradually filled 
 up by the deposition of successive layers of gray 
 substance secreted by the pia mater, which has 
 insinuated itself into the canal. 
 
 This account does not appear to me correct and 
 conformable to nature. I allow that the two cords 
 unite at the bottoms of the clefts, but I likewise 
 maintain that each contains gray matter in its in- 
 terior, in the direction of the two nervous roots 
 that are implanted. But were the spinal mass 
 developed, and its canal obliterated, as M. Serres 
 would have us believe, by the deposition of gray 
 substance in successive layers, this process ought, 
 evidently, to go on in the interior of each of the 
 cords composing it, and not in the canal between 
 the two similar halves. 
 
 The corresponding parts of each half of the 
 
57 
 
 spinal cord are voluminous in the ratio of their 
 implanted nerves. This proposition is strikingly 
 exemplified, by comparing the spinal cord of ani- 
 mals, whose superior are larger than their inferior 
 extremities, with that of others, whose inferior are 
 of greater size than their superior limbs. 
 
 I have already said that there is a mass of gray 
 substance contained in the interior of each half 
 of the spinal cord, proportionate, in quantity, to 
 the volume of the corresponding parts of the same, 
 and to the nervous roots that issue at the place. 
 The gray substance is disposed in a crescent form 
 on either side of the apparatus of union, towards 
 which the concave aspects are turned. (PI. i. fig. 
 9 and 10). 
 
 The white fibres of the spinal cord, on both 
 abdominal and dorsal surfaces, follow the gray 
 substance throughout its extent, so that there 
 are two nervous roots in each half : one dorsal, 
 another abdominal. (PI. i. fig. 9 and 10.) The 
 dorsal roots, generally, and the entire dorsal mass 
 (PI. i. fig. 9 and 10), are more considerable than 
 the abdominal roots and corresponding half. The 
 dorsal roots communicate with the intervertebral 
 ganglions (pi. i. fig. 3, 4, a— a), and the latter 
 are proportionate to the former. 
 
 No division of the spinal cord into dorsal and 
 abdominal portions is effected by two such chan- 
 nels as separate it into halves laterally; it is, 
 at most, only marked by the ligamentum d&ntatum 
 
58 
 
 which attaches the cord, on either side, to the dura 
 mater. (PI. i. fig. 3, 4, 5, and 6.) Neither is it 
 proper to look on the lateral portions of the spinal 
 cord, as each composed of three bundles extend- 
 ing from its one to its other extremity. They are 
 much rather to be considered as nervous mem- 
 branes folded on themselves, and forming a tube, 
 containing gray substance. (PI. i. fig. 10.) 
 
 The fissures on the abdominal and dorsal aspects 
 of the spinal cord, are quite constant. The first 
 is shallower, but more conspicuous, than the other. 
 (PI. i. fig. 10.) 
 
 The abdominal nervous roots of the spinal 
 cord communicate with the nerves of the thorax 
 and abdomen ; those of the dorsal surface fre- 
 quently inosculate, and filaments from one pair 
 of nerves often run to join the fasciculi composing 
 another. (PI. i. fig. 5.) 
 
 Among the general considerations on the spinal 
 cord, the question respecting its uses still remains 
 for examination. 
 
 Anatomists have been in the frequent habit of 
 speaking of a central mass in the nervous sys- 
 tem, from which they conceive all its other parts 
 to arise. The brain, cerebellum, and spinal cord, 
 have very commonly been so entitled. M. de 
 Blainville, however, separates the brain and ce- 
 rebellum from the central mass. These he ar- 
 ranges along with the external senses and inter- 
 vertebral ganglions under the general title, Gan- 
 
59 
 
 glionary Portion of the nervous system, and he 
 confines the central mass exclusively to the spi- 
 nal cord and medulla oblongata. In his view, 
 the ganglionary is only added to, and not derived 
 from, or produced by, the central portion. The 
 two nervous roots of the spinal cord are, he says, 
 mere fibres of communication between the cen- 
 tral part of the nervous system and the nerves of 
 sensation and voluntary motion, which originate 
 in the intervertebral ganglions. 
 
 To me anatomical, as well as physiological, 
 facts, seem to militate against this opinion of 
 M. de Blainville. In the first place, the inter- 
 vertebral ganglions belong to the dorsal roots 
 only of the spinal nerves. Our author, conse- 
 quently, forgets to mention the origin and use of 
 the abdominal roots entirely. But is it not pro- 
 bable, that both dorsal and abdominal roots arise 
 in the same manner? The filaments of the spinal 
 roots, too, are in proportion to the corresponding 
 masses of the cord whence they issue. Now, as 
 the abdominal roots have no intervertebral gan- 
 glions, and as they are evidently detached from 
 the spinal cord, ought we not to conclude that the 
 dorsal roots are so in like manner ? 
 
 Another proof of the untenableness of M. de 
 Blainville’s notion, exists in the size of the ner- 
 vous filaments of the spinal cord. The apparatus 
 of communication is never so large as the parts 
 that communicate ; what a difference, for ex- 
 
60 
 
 ample, between the volume of the nervous 
 masses of vegetative and of phrenic life, and their 
 communicating fibres ! 
 
 Neither is M. de Blainville’s opinion supported 
 by physiology. The ganglionary portion, he con- 
 ceives to be sufficient for the performance of its 
 own functions, that is to say, adequate of itself 
 to feel, and to cause the execution of voluntary 
 motion ; what then becomes of the central por- 
 tion ? what is its use ? Admitting it to establish 
 communications between the different parts of 
 the nervous system, it cannot, however, exist 
 solely for such a purpose ; its volume is by much 
 too considerable to permit such a supposition 
 to be entertained. Again, it most certainly is 
 not destined to the affective and intellectual 
 operations, for there is no proportion between 
 them and the developement of the spinal cord. 
 On the contrary, it is certain that general sensa 
 tion and voluntary motion are in direct relation 
 to the volume of the nervous masses of the ver- 
 tebral column. Animals, eminently endowed with 
 these two functions, have always a considerable 
 spinal cord, and its parts proportionate to the 
 organs which receive their nerves from thence. 
 The several parts of the spinal cord are also 
 augmented, as the apparatuses of sensation and 
 of motion are increased in number or size. 
 Further, the spinal cord is developed at a much 
 earlier period of life than the cerebral masses ; 
 
 * 
 
61 
 
 it has acquired solidity and firmness, while the 
 brain is still pulpy and devoid of fibres; and in 
 harmony with this law, children display great 
 muscular activity, — their love of bodily exercise 
 is insatiable, before their mental faculties appear 
 in any degree of vigour. 
 
 M. Serres, who admits all the organic systems, 
 the nervous in particular, to be developed from 
 the circumference towards the centre, maintains 
 that the nerves are fully developed when the 
 spinal cord and brain are still in a fluid state. In 
 conformity with this his hypothesis, he denies 
 that the spinal cord gives origin to its nerves. 
 These, according to him, are only implanted 
 into it. 
 
 Dr. Bailly conceives, as I have said, the same 
 nervous elements to belong to every particular 
 vertebra, i. e . , nerves of sensation, of motion, of 
 digestion, and of the intellectual functions. He 
 speaks of eight cords that compose the intellec- 
 tual system of the vertebral column : the infe- 
 rior mediam cord, continuous with the pyramidal 
 eminence, and terminating anteriorly in the ce- 
 lebral hemisphere ; the lateral inferior cord, end- 
 ing in the internal layer of the corpora quadrige- 
 mina ; the superior lateral cord, which termi- 
 nates in the cerebellum ; and the inferior median 
 cord, finishing in the lateral convolutions of the 
 medulla, — convolutions which are most largely 
 
62 
 
 developed in cartilaginous fishes, and which cor- 
 respond to the ribbon of gray substance of mam- 
 miferous animals. These eight longitudinal 
 cords, four on each side, according to this au- 
 thor, exercise functions analagous to those of the 
 cerebral hemispheres, the internal slip of the 
 quadrigeminal bodies, the cerebellum, and the 
 lateral convolutions of the fourth vertricle in 
 fishes, or the gray band in the mammalia. The 
 medulla oblongata, in the same gentleman’s view, 
 presents alternately an intellectual cord and a ner- 
 vous pair. 
 
 These physiological suppositions will, I make 
 no doubt, share the fate of so many others, that 
 are now forgotten. In my opinion, the spinal 
 cord is, 1st, the origin of the nerves styled 
 spinal ; 2nd, an apparatus that contributes to 
 muscular and sensitive powers ; and 3rd, a means 
 of communication between the cerebral opera- 
 tions, the sense of touch, the power of motion in 
 general, and the functions of vegetative life col- 
 lectively. 
 
 Particular Considerations in regard to the Spinal 
 Cord. 
 
 Before the development of extremities in the 
 embryo, in animals also that naturally have none, 
 and in cases of monstrosity where they are want- 
 
63 
 
 ing, the spinal cord has no enlargements. These 
 appear with, and are in proportion to, the extre- 
 mities.' 
 
 In the lower animals the spinal cord extends 
 farther into its bony canal than in the human 
 kind. Up to the fourth month of the human 
 embryo’s existence, it runs to the extremity of 
 the coccyx ; but the peculiar structure, termed 
 cauda equina, which is more remarkable in man 
 than in any other animal, becomes more and 
 more apparent after this period. The caudal ap- 
 pearance is produced by the sacral and lumbar 
 nerves. 
 
 The spinal cord of the human kind com- 
 monly terminates by one or two little knobs, (of 
 which the superior, when there are two, is the 
 larger,) opposite to the second lumbar vertebra, 
 and it is then attached by means of a tendinous 
 slip to the bottom of the vertebral canal. 
 
 The spinal cord is commonly divided into four 
 portions: a cervical, dorsal, lumbar, and sacral. 
 Each of these detaches several pairs of nerves, 
 the number of which varies in different species 
 of animals ; in man it amounts to thirty pairs, 
 five being sacral, a like number lumbar, twelve 
 dorsal, and seven cervical. 
 
 The spinal cord of man, as of animals, is en- 
 larged, and contains a larger quantity of gray 
 substance at those places where the great nerves 
 of the extremities are detached, than at any 
 
64i 
 
 oilier. Although many anatomists, M. Serres 
 among the rest, deny that the spinal cord of man 
 and animals is enlarged at, and contracted be- 
 tween, the origins of each pair of nerves, I still 
 adhere to the opinion which, in conjunction with 
 Dr. Gall, I published long ago ; and I again ap- 
 peal to nature for confirmation of its accuracy. 
 These alternate enlargements and contractions 
 are more or less conspicuous, in the ratio of the 
 volume of the nervous pairs ; they are, for in- 
 stance, more apparent in the ox and horse than 
 in man. If, however, the human spinal cord, 
 stripped of its dura mater, and arachnoid cover- 
 ing, be held profile-wise against the light, the 
 undulated line of its edges will be abundantly 
 obvious. In the large work on the “ Anatomy of 
 the Brain and Nervous System,” we have given 
 drawings of this structure from the spinal cord of 
 the calf and of man. PI. i. fig. 3, is a portion 
 of the spinal cord of a calf. 
 
 Several anatomists have spoken of numerous 
 transverse folds to be observed, especially on the 
 abdominal surface of the spinal cord ; these be- 
 come very distinct when the cord is taken from 
 out its bony canal, and one end is brought towards 
 the other; they disappear entirely, however, 
 when the part is stretched. Such folds, there- 
 fore, appear to result from the bending ot the 
 cord, and not to belong to any original pecu 
 liarity of organization. 
 
65 
 
 On either side, and at some little distance from 
 the great median fissure, two superficial channels 
 may be observed on the dorsal surface of the 
 human spinal cord (pi. i. fig. 5, a — a.) They ex- 
 tend as far as, or a little way beyond, the first 
 dorsal vertebra. The two bands between the 
 median and these superficial fissures, are de- 
 veloped at the earliest period ; their structure is 
 even complete, when the rest of the spinal cord 
 is still a grayish and pulpy mass. The bands on 
 the external edges of the dorsal and abdominal 
 median fissures, appear, in general, to attain ma- 
 turity of structure before any of the lateral masses. 
 
 By opening the mesial abdominal fissure, and 
 stripping off the vascular tissue, the nervous fibres 
 will be seen running lengthwise and parallel to 
 the lateral bands, (pi. i. fig. 6 ;) but in the dorsal 
 cleft, they will be found descending perpendicu- 
 larly from the surface towards its bottom. (PI. i. 
 fig. 7.) 
 
 The structure of the apparatus of union has not 
 the same appearance at the bottom of both fissures. 
 If the edges of the one on the dorsal aspect be 
 gently separated, two white bands will be disco- 
 vered running lengthwise (pi. i . fig. 7, S- — 9-) , almost 
 as occurs in the middle line of the great cerebral 
 commissure (raphe of the corpus callosum) ; at 
 the bottom of the abdominal fissure, on the con- 
 trary, filaments will be observed running trans- 
 versely from the sides towards the median line. 
 
 F 
 
66 
 
 These bundles do not meet, they rather interlace, 
 each terminating on either side between the two 
 that come from the opposite side. (PI. i. fig. 6,^ — &.) 
 
 Besides the peculiarities of its shortness com- 
 pared with the vertebral canal, and of its termina- 
 tion in the cauda equina, the spinal cord of man 
 presents another striking peculiarity in the direc- 
 tion in which its nerves are detached. The 
 direction in which the spinal nerves are sent off, 
 varies widely in different classes of animals. In 
 man, their course is downwards and outwards ; this 
 depends evidently on the vertical posture, by 
 which man is distinguished from the other mam- 
 malia, and on the shortness of his spinal cord 
 compared with its bony canal. In the human 
 kind, only the first pair of cervical nervous roots 
 on the dorsal surface (pi. i. fig. 5), and the two 
 first pairs upon the abdominal (pi. i. fig. 4), 
 have one set of bundles coming from above, down- 
 wards, and another from below, upwards ; all the 
 other pairs are detached more and more obliquely 
 downwards, to gain the vertebral holes by which 
 they issue, in proportion as they arise nearer to 
 the sacral extremity of the spinal cord. In other 
 animals, on the contrary, whose spinal nervous 
 masses occupy the entire length of the vertebral 
 canal, the nerves are sent off directly opposite to 
 the intervertebral spaces at which they issue. 
 (PI. i. fig. 3.) 
 
 I have still to speak of the superior extremity 
 
67 
 
 of the spinal cord. By the words spinal marrow 
 or cord, most anatomists understand the nervous 
 mass that extends throughout the spinal canal 
 up to the occipital hole; others, Messrs. Soem- 
 merring and Chaussier among the number, say 
 that it goes as far as the annular protuberance. 
 They consequently include the pyramidal and 
 olivary bodies, the accessory, vocal, glossopha- 
 l’yngeal and hypoglossal nerves, all the mass, in 
 short, commonly named medulla oblongata , They 
 speak of two portions — one cranial, another spinal, 
 of the spinal cord; the first being, of course, con- 
 tained in the skull, the second in the canal of the 
 vertebral column. 
 
 The organization of the spinal nervous mass 
 cannot be said to change entirely when it enters 
 the cranium: several pairs of nerves are still de- 
 tached precisely in the same manner as they are 
 in the spine; the nerves too, in both cases, per- 
 form similar functions. The proper spinal masses 
 are also intimately connected with those of the 
 medulla oblongata. In this last part, however, the 
 abdominal fissure is interrupted by the decussa- 
 ting bundles of the pyramidal bodies ; the size of 
 the mass is also very sensibly increased here, and 
 there is no regular proportion between the proper 
 spinal cord and the mass that extends from the 
 occipital hole to the annular protuberance. More- 
 over, the roots of several cerebral nerves, as they 
 are styled, are found in this last mass, as also the 
 
 F 2 
 
68 
 
 rudimentary parts of the brain and cerebellum. 
 Lastly, the word spinal refers to a particular situa- 
 tion — the spine. These reasons may suffice to 
 make us limit the title spinal cord to the mass 
 included in the vertebral canal, and extending 
 from the occipital hole or commencement of the 
 pyramidal decussation to the cauda equina or 
 horse’s tail. 
 
 CHAPTER II. 
 
 Of the pretended Cerebral Nerves ; or, of the Cranial 
 Nerves of the External Senses and Voluntary 
 Motion. 
 
 It is usual for anatomists to consider the ner- 
 vous mass lying between the occipital hole 
 and annular protuberance, as distinct and particu- 
 lar. In former times, this part was taken for a 
 prolongation of the brain and cerebellum, and, 
 therefore, called medulla oblongata. In man it is 
 composed of parts, named severally, pyramidal 
 bodies, which are two in number, anterior (pi. vi. 
 fig. 1., 1 — c.) and posterior (pi. xi. in the middle 
 line) ; olivary bodies (pi. vi. fig 1 , a.); restiform 
 bodies (pi. xi. e. e.) ; accessory nerves (pi. i. fig. 3, 
 4, and 5; pi. vi. fig. 1,2 — 3); hypoglossal nerves 
 /pi. vi. 4) ; vocal nerves (ib. 6) ; glossopharyngeal 
 
69 
 
 nerves (ib. 7)7 < auditor y nerves ( ib - 9 ) ; facial 
 nerves (ib. 11); ana abductor nerves (ib. 10.) 
 
 At the conclusion of thP last chapter, I remarked 
 that it was a mistake to coi?f° und die part called 
 medulla oblongata and the spinal cord together. 
 I here subjoin that the medulla oblongata j s no t 
 a separate and particular nervous ma.ss : it gives 
 origin to the nerves above-mentioned, atfd also to 
 the fifth pair; but there is yet one portion of each 
 of its halves which belongs, decidedly, to the 
 cerebellum, and another which pertains to the 
 brain. 
 
 The volume of the medulla oblongata yaries 
 greatly in the different classes of animals ; its size 
 is determined by the nerves that arise from if* 
 and by the bundles that proceed to the cerebellum 
 and brain. Its increase beyond the size of the 
 spinal cord, is more remarkable in reptiles than 
 in fishes, in birds than in reptiles, and is espe- 
 cially considerable in the mammalia, which, gene- 
 rally, have the medulla oblongata as well as spinal 
 cord proportionately larger than man, because the 
 nerves detached from these parts are larger in 
 them than in the human kind. 
 
 At present, I mean only to speak of the sup- 
 posed cerebral nerves. The pyramidal, olivary, 
 and restiform bodies will be examined along with 
 the cerebellum and brain of which they are parts. 
 
 The opinions of authors upon the origin of the 
 nerves of the head, are very various. In general 
 
70 
 
 they are derived from the brain, hence their 
 name cerebral. But some writers limit the title 
 brain to the hemispheres, and join the striated 
 bodies, the optic tbalami, the cerebral legs and 
 annular protuberance to the medulla oblongata; 
 or, otherwise, they look on all these as parts of 
 the spinal cord, and then say that no nerve what- 
 ever arises from the brain, that is, from the hemi- 
 spheres immediately. By thus extending the limits 
 of the medulla oblongata and spinal cord, how'- 
 ever, parts that belong essentially to the brain 
 are included. The principle we lay down, there- 
 fore, that no nerve originates in the brain, and 
 that every nervous part has its own origin, so that 
 the nerves can no more be derived from the brain 
 than can the various nervous pairs from each 
 other, cannot possibly be confounded with any 
 of the foregoing opinions of authors. 
 
 The proofs we adduce in support of our posi- 
 tion, as to the independent origin of the various 
 nervous parts, are constantly the same ; all, there- 
 fore, that has been said to demonstrate the spinal 
 cord to be no continuation of the brain, applies to 
 the nerves of the head, and proves that they do 
 not owe their being to the brain, and that no one 
 pair derives its existence from any other. In the 
 first place, the nerves of the head bear no pro- 
 portion to the brain in size; and then, these 
 nerves exist in acephalous monsters, whose brain 
 never had being. Moreover, the course taken 
 
71 
 
 by the nerves towards the cranial holes through 
 which they pass, proves in the most positive man- 
 ner that they are not continuations of the cerebral 
 fibres. In examining the individual nerves, I 
 shall speak of their several peculiarities, as origin, 
 structure, and connexion are concerned. 
 
 The nerves of the head, as of the spine, have 
 been long classed into pairs. The number of 
 pairs reckoned, how r ever, varies considerably ; 
 sometimes they are said to be seven, sometimes 
 eight, or nine, or according to M. Soemmerring’s 
 method of counting as many as twelve. How- 
 ever, the mode of indicating the several pairs of 
 nerves numerically, and speaking of the first pair, 
 the second pair, the third pair, and so on, pos- 
 sesses no practical advantages, because, besides 
 the number, the functions of each pair must still 
 be learned. It is better, therefore, to designate 
 each pair of the cranial nerves in succession from 
 its functions or its destination. 
 
 Some authors have divided the nerves accor- 
 ding to their places of detachment, into nerves of 
 the brain, of the cerebellum, of the annular protu- 
 berance, and of the medulla oblongata. This 
 attempt at classification was necessarily very de- 
 ficient, for it is based upon an error in regard to 
 the origins of the nerves ; the actual place of 
 origin being confounded with that at which they 
 issue immediately from the general mass. 
 
72 
 
 Of the Accessory Nerve. 
 
 The accessory nerve is found in man and the 
 other mammalia. (PI. i. fig. 3, 4, 5, and pi. vi. 
 fig. 1, 2 — 3.) It arises from the cervico-spinal 
 
 mass and medulla oblongata. Its filaments come 
 from the dorsal surface of these parts, and vary 
 in number, in thickness, and in length, not only 
 in different individuals of different species, but 
 even on the two sides of the same subject. The 
 first filaments are detached at various heights, 
 sometimes higher, sometimes lower, in the spinal 
 cord, issuing from the level of the seventh cervi- 
 cal pair in one instance, and from that of the fifth 
 in another. The accessory recedes from the 
 spinal cord and medulla oblongata, as it ap- 
 proaches the pneumogastric nerve, along with 
 which it escapes from the cranium. I have al- 
 ready said, that Mr. Charles Bell arranges the 
 accessory among the nerves of respiration. In 
 contributing to this function, it produces mo- 
 tion, and is influenced by the will ; nevertheless 
 it is detached, as we have seen, from the dorsal 
 surface of the spinal cord. 
 
 Of the Pneumogastric Nerve. 
 
 The pneumogastric occurs in all vertebral! ani- 
 mals. In man (pi. vi. fig. 1, 6), it issues by nu- 
 
73 
 
 merous filaments between the olivary, (ibid a,) 
 and the restiform (e e) bodies, nearer to the lat- 
 ter, however, than to the former. It unites with 
 a great number of other nerves, a circumstance 
 that has obtained for it the title vagus. Its 
 branches run to the larynx and pharynx, to the 
 thyroid gland, the vessels of the neck, and the 
 great conduits of the heart, to the lungs, the 
 liver, spleen, pancreas, stomach, and duode- 
 num. As some of its principal branches are dis- 
 tributed to the organs of voice, and as its le- 
 sions derange the functions of these parts, it has 
 also been called the vocal nerve. The commu- 
 nications by its means established, and its ex- 
 tensive distribution, explain the sympathies 
 that exist between the throat, lungs, stomach, 
 heart, &c. 
 
 Of the Glossopharyngeal Nerve. 
 
 In the mammalia and man, (pi. vi. fig. 1, 7,) 
 this nerve comes off from the medulla oblongata, 
 just before the pneumogastric, by a great many 
 filaments, which, speedily uniting into one or 
 more bundles, compose a trunk that runs to be 
 ramified on the pharynx and muscles of the 
 tongue. It appears to be destined to general 
 sensation. 
 
74 , 
 
 Of the Hypoglossal Nerve. 
 
 The hypoglossal in man arises partly near the 
 olivary and pyramidal bodies, and partly lower 
 down, by several filaments that are detached, 
 and get united after the manner of the cervical 
 nerves.- (PL vi. fig. 1, 4.) It supplies the tongue 
 with motive power, and acts in mastication, de- 
 glutition, speaking, singing, &c. 
 
 Of the Abductor Nerve of the Eye. 
 
 This nerve arises in all mammiferous animals, 
 from the abdominal surface of the medulla ob- 
 longata. (PI. vi. fig. 1, 10.) In some, as the 
 horse, ox, and deer, it mounts all the way along 
 with, and by the side of, the pyramidal bodies, 
 in the form of a band, which, on reaching the 
 annular protuberance, divides into two. In the 
 human subject it is generally covered by some 
 transverse fibres of the protuberance. Its dis- 
 tribution, as its name implies, is to the abductor 
 muscle of the eye. 
 
 Of the Facial Nerve. 
 
 The facial is detached from the spinal cord in 
 the same manner as the nerves I have just dis- 
 cussed. Its true origin is readily seen in the 
 
75 
 
 lower animals ; but in man, (pi. vi. fig. 1 , 11,) it 
 (or some of its filaments at least) seems to come 
 from the annular protuberance. This happens 
 in consequence of its being covered entirely, or 
 partially, by the transverse fibres of the part 
 mentioned. The distribution of this nerve is to 
 the muscles of the face ; it also communicates 
 freely with all the three branches of the fifth 
 pair. 
 
 Of the Motor Nerve of the Eye. 
 
 The filaments composing this nerve, (pi. vi. 
 and pi. x. fig. 1, 15,) issue from the blackish 
 body of the cerebral legs (pi. x. fig. 1, 30) ; 
 these unite and go to supply the superior, inter- 
 nal, inferior straight, and inferior oblique, muscles 
 of the eye, and the elevator of the upper eye-lid. 
 It is detached in all vertebral animals, from the 
 cerebral crura behind the tuber cinereum, or ash- 
 coloured tubercle, (pi. vi. 17,) which is situated 
 immediately backwards from the junction of the 
 optic nerves. 
 
 Of the Nerve of the Superior Oblique Muscle of the 
 
 Eye. 
 
 This nerve, (pi. vi. 13,) springs by several fila- 
 ments behind the posterior pair of quadrigemi- 
 nal bodies in the mammalia, (pi. xi. fig. 1, o,) and 
 
76 
 
 behind the bigeminal bodies in the other classes 
 of animals. It has no prerogative over the other 
 nerves of motion in expressing the affections and 
 passions ; the name patheticus, or ogling nerve, 
 therefore, which it has obtained, is misapplied. 
 Although a nerve of motion, it arises from the 
 dorsal surface of the nervous mass. 
 
 Of the Trigeminal Nerve. 
 
 The trigeminal (pi. vi. fig. 1, 12) arises from 
 the medulla oblongata. Its place of origin is ap- 
 parent in those animals, as reptiles, birds, and 
 fishes, which have no annular protuberance, and 
 also in the mammalia which have it of small size; 
 but in man, the monkey, and other tribes, where 
 this part is very large, the trigeminal seems to 
 arise from it; the nerve, however, is, in fact, only 
 covered by some of its transverse fibres, (pi. viii. 
 fig. 1, i — k.) and the origin of the nerve is, in fact, 
 the same in all animals. To shew it in the hu- 
 man kind, the fibres of the annular protube- 
 rance that cover it, must, of course, be dissected 
 away. 
 
 The trigeminal nerve is distributed to every 
 part of the face, to the muscles of the forehead, 
 of the eye-lids, nose, lips, jaws, and ears ; it 
 communicates with the organs of all the five 
 senses, and of voluntary motion, and brings 
 these and the other parts of the body, the face, 
 
77 
 
 neck, trunk, and extremities, into relationship 
 mutually. 
 
 One branch of the trigeminal is ramified on 
 the tongue, and is regarded as the true gusta- 
 tory nerve. It is, therefore, destined to cognize 
 an impression of a specific kind, viz., taste. If 
 some feel disposed to regard taste as a sort of 
 touch, they must, at least, admit the impossibility 
 of confounding or assimilating this species of per- 
 ception with sensation in general. 
 
 • 
 
 Of the Auditory Nerve. 
 
 The auditory (pi. vi. 9), as well as the nerve 
 last discussed, must exist in the avertebral 
 tribes, but its origin and peripheral expansion 
 only become distinct and complex as we ascend 
 in the scale of beings. The origin of the audi- 
 tory nerve is in many fishes confounded with 
 that of the facial and trigeminal ; in some kinds, 
 however, it is more distinct, and is the same as 
 in reptiles and birds. The auditory nerve always 
 arises laterally and posteriorly to the cerebellum. 
 In the mammalia it comes from the fourth ven- 
 tricle, and traverses in its course a band of gray 
 substance, lying between the restiform body and 
 the cerebellum. In man certain white lines may 
 commonly be seen in the fourth ventricle, (pi. ix. 
 fig. 1. t.) which Piccoluomini was the first to con- 
 sider as the origins of the auditory nerve. These 
 
78 
 
 lines, or streaks, are almost imperceptible in some 
 subjects, but in others they are very numerous 
 and distinct. They are observed to vary on each 
 side, being occasionally larger and more nume- 
 rous on one than on the other Sometimes they 
 occur disposed in rays, sometimes in pencils, 
 and, again, they run in parallels, often lying 
 higher on one than on the other side. They at 
 one time appear as little flattened bands, at ano- 
 ther as rounded and salient cords. Piccoluo- 
 mini’s opinion of their use seems now to be very 
 generally adopted ; it is certain, indeed, that 
 some of them do unite with the auditory nerve, 
 but others run to the anterior cerebellar lobes, and 
 others dip into the middle of the cerebellum. 
 Although many of the mammalia have much 
 larger auditory nerves than man, these white 
 fibres are nevertheless wanting in all. In them, 
 there is a broad band on either side, extending 
 from the one auditory nerve to the other, imme- 
 diately behind the annular protuberance, and 
 above all the ascending bundles, except the py- 
 ramidal bodies. (PI. iv. fig. 2, c.) This band ap- 
 pears to be an apparatus of union or commissure. 
 It does not give origin to the facial nerve, as some 
 anatomists have supposed. 
 
 Of the Optic Nerve. 
 
 Since the days of Eustachius and Varolius, the 
 
79 
 
 majority of anatomists have derived this nerve 
 (pi. vi. fig. 1, 20.) from certain masses, which 
 have, in consequence, been entitled thalami of 
 the optic nerves. (Pl. x. fig. 1, p .) Others, 
 however, followed some of its fibres backwards 
 to the anterior of the quadrigeminal bodies. (PI. 
 xi. fig. 1, n .) And it is easy in the mammalia to 
 do this. A broad slip issues from the anterior 
 quadrigeminal body of either side, which turns 
 round upon the outer edge of the thalamus, 
 simply superimposed upon the cerebral crura, 
 but attached to the neighbouring masses along 
 its external edge, as far as its junction with 
 its fellow of the opposite side. (PI. viii. fig. 1, w, 
 iv, iv.) From the tuber cinereum, (pl. vi. fig. 1, 
 17.) the optic nerve receives many additional 
 fibres, which join it in right lines, and without 
 decussating. (Pl. viii. fig. 2, 20.) 
 
 It is the opinion of many anatomists, that the 
 optic nerves, at their junction, unite intimately 
 without decussating ; many others, on the con- 
 trary, think that either nerve crosses to the side 
 opposite to that on which it had arisen. The 
 numerous cases described by authors, and the 
 facts which Dr. Gall and I have collected, prove 
 that atrophy of one optic nerve is continued on 
 the opposite side after the junction of the two. 
 
 We, therefore, agree with those who recognise 
 a partial decussation of the optic nerves in man 
 and the mammalia. The fibres of the outermost 
 
80 
 
 portions appear to continue their course onwards 
 without decussating. 
 
 It was a great error to consider the eminences 
 called optic thalami, as the sources of the optic 
 nerves. There is, in fact, no proportion what- 
 ever between these parts and the nerves of vision. 
 In the horse, ox, sheep, &c., the optic nerves are 
 as large as in man, but the thalami, in the human 
 kind, are much larger than in these animals. 
 
 A very cursory examination of the structure of 
 the thalami also shows a mere superficial layer 
 attached to the optic nerve and the whole of the 
 interior fibres proceeding in a divergent manner, 
 backwards, to be distributed to the cerebral 
 convolutions. (PI. x. fig. 1 , p. P. P.) 
 
 When the optic nerve is affected with atrophy, 
 the corresponding thalamus is diminished only 
 in as far as the nerve itself is lessened; the inte- 
 rior of the thalamus suffers no change, but the 
 atrophy of the nerve continues on to the anterior 
 quadrigeminal body which belongs to it. I once 
 found, in the brain of a woman who had died 
 insane, the thalamus of the left side half converted 
 into pus; the corpus striatum of the same side 
 was also much shrunk, but the optic nerve was 
 healthy, and resembled, in all respects, its fellow 
 of the opposite side, in the vicinity of which no 
 organic change could be detected. The anterior 
 pair of quadrigeminal bodies were also in their 
 natural state. 
 
81 
 
 The two thalami are rarely of equal size ; the 
 one on the left side is commonly the smaller. It, 
 therefore, becomes necessary to guard against 
 attributing to atrophy of an optic nerve an ap- 
 pearance that depends on natural conformation. 
 
 Until Dr. Gall and I showed the mistake, the 
 optic tubercles of birds and reptiles were con- 
 founded with the thalami; these tubercles (pi. xi. 
 fig. 2 and 3, n.), however, correspond to the ante- 
 rior pair of quadrigeminal bodies. The parts, 
 called thalami (pi. xi. fig. 2, p.), also exist in the 
 two classes of creatures mentioned, besides the 
 true optic ganglions, (ib. n .) 
 
 It is a difficult matter to say whether the long 
 elevated bodies that occur immediately behind 
 the crossing of the optic nerves in fishes (pi. ii. fig. 
 P, 6, 8, 16), and correspond to the optic ganglions 
 of birds, that is to say, to the pair of ganglions 
 (pi. iii. fig. 5, 6, 7, 10, and 11, n.) which comes im- 
 mediately after the cerebellum, or whether they 
 ought to be likened to the bodies which are styled 
 mammillary. (PI. vi. fig. 1, 16.) The optic nerves 
 of fishes seem to arise from, at all events they 
 communicate with, these bodies. By comparing 
 pi. ii. fig. 4< and 6, 16, with pi. iii. fig, 12, n., the 
 optic ganglions in birds, and especially in mam- 
 miferous animals, will be seen to be separated 
 and pushed upwardly and laterally by the medulla 
 oblongata, cerebral legs, and annular protube- 
 rance. Moreover, the optic nerves in fishes adhera 
 
 G 
 
82 
 
 to several other parts, as they do in the higher 
 classes of vertebral animals and in man. It is 
 from this circumstance that a great part of the 
 other masses, especially those that follow the 
 cerebellum, are called optic ganglions; but these 
 bear no proportion to the optic nerves (pi. ii. fig. 
 5, 7, and 10, n.), and to me, it seems more rea- 
 sonable to allow, with M. Arsaky*, that the 
 complicated structure of the optic ganglions in 
 fishes, explains the functions of the derived nerves, 
 which, in reptiles, birds, and the mammalia, are 
 evidently aided in their functions by the other 
 parts with which they communicate. 
 
 The implantation of the optic nerve in fishes 
 into the inner edge of its ganglion, which causes 
 the greatest part of this mass to appear before 
 and above it, bears a striking analogy to the 
 adhesion of the same nerve to the brain in other 
 classes of animals, and confirms the idea in ques- 
 tion. It is rendered still more probable, as the 
 same peculiarity of structure is found in con- 
 nexion with the olfactory nerves of fishes. And 
 further, the oblong bodies, which, in fishes, lie 
 behind the crossing of the optic nerves, cannot 
 possibly be supposed analogous to the mammillary 
 bodies of mammiferous tribes, because these last 
 belong to the fornix, and this is a part which 
 fishes have not. I may still add that the mammil- 
 
 * Dissertatio de Piscium Cerebro et Medulla Spiuali; Halce. 
 1313. 
 
83 
 
 lary bodies bear no proportion to the optic nerves, 
 and that the oblong bodies of fishes above-men- 
 tioned do, regularly. 
 
 The oblong bodies of fishes, probably, corre- 
 spond to the gray tubercle, (tuber cinereum) of 
 the mammalia. This tubercle, in the higher classes 
 of beings, always sends fibres to the optic nerves, 
 which, after this accession, advance of increased 
 size in their course. (PI. viii. fig. 2 — 17.) 
 
 The connexion of the optic nerve with such a 
 number of cerebral parts, renders its exact origin 
 uncertain. To appreciate this truth in its full 
 force, it will be necessary to reflect on what I 
 have still to say of the quadrigeminal bodies. 
 
 Of the Quadrigeminal Bodies. 
 
 The title, corpora, or tubercula quadrigemina, is 
 applied to two pairs of round elevations, situated 
 behind the legs of the brain. They are only 
 found in the mammalia and in man. (PI. xi. fig. 1, 
 n, o .) They are joined together by a transverse 
 band (ib. x), and they communicate with the 
 part called valve of Vieussens (ib. y ), with the 
 bundles that proceed from the medulla oblongata, 
 and with the pretended optic thalami (ib. p.). I 
 have already spoken of the large band, belonging 
 to the optic nerve, that issues from the anterior 
 pair of these bodies. Being in communication 
 with the bundles which come from the posterior 
 
 G 2 
 
84 . 
 
 part of the medulla oblongata, there can be no 
 doubt but the quadrigeminal bodies have their 
 origin lower down in this nervous mass ; but as 
 the optic nerves arise from the anterior pair in 
 the mammalia, and as these nerves issue in birds 
 from a couple of ganglions, separated from the 
 general cerebral mass, (for, in birds, they are only 
 united to the bundles that proceed from the me- 
 dulla oblongata) the analogy and office of these 
 ganglions cannot be called in question. The 
 destination of the posterior pair of quadrigeminal 
 bodies is much less obvious. 
 
 M. Serres* thinks that the bigeminal tubercles 
 of fishes, reptiles, and birds, and the quadrigemi- 
 nal bodies of mammiferous animals and man, are 
 the same mass, destined, in all, to originate the 
 optic nerves, and that the division into two pairs 
 happens merely from a transverse furrow, which, 
 as it runs more or less forwards or backwards, 
 equalizes them, or causes in one case the ante- 
 rior, in another the posterior pair to predominate. 
 
 The posterior are intimately connected with 
 the anterior tubercles, it is true ; but there is a 
 white band which issues from the anterior pair, 
 joins a small collection of gray substance, called 
 oorpus geniculatum externum (pi. viii. fig. 1, q), is 
 thereby increased in size, and then continues its 
 course into the optic nerve ; in like manner there 
 
 * Anatomie du Cerveau ; Preface. Rapport de M. Cuvier. 
 
85 
 
 runs a band from the posterior pair, which unites 
 with a mass of gray substance, entitled corpus 
 geniculatum internum (pi. xi. fig. 1, r-)> and gain- 
 ing, consequently, in size, afterwards dips under 
 the optic nerve, and is continued on towards the 
 middle cerebral lobe. ' This structure proves, at 
 the least, that the anterior and posterior pairs of 
 the quadrigeminal bodies are no parts of one and 
 the same nervous mass. 
 
 M. Serres also fancies that the corpora quadri- 
 gemina serve as a basis, according to which the 
 other parts of the encephalon are determined 
 (“ les tubercules quadrigeminaux servent de base a la 
 determination des autres parties de I’encephale ); ” and 
 he investigates their relations with many particular 
 cerebral parts. His assumption seems to me as 
 incorrect and untenable as the one I have just 
 examined, according to which, the quadrigeminal 
 bodies are parts of one mass similar to the bige- 
 minal tubercles of birds and reptiles. 
 
 “ The quadrigeminal tubercles,” says M. Serres, 
 “ are developed in all the classes, and in every 
 family of each class, in a ratio, directly as are the 
 optic nerves and the eyes. Fishes have the largest 
 quadrigeminal tubercles, and the most remarkable 
 eyes and optic nerves. The very considerable 
 size of their quadrigeminal bodies, indeed, has 
 led anatomists, up to the present time, into the 
 error of supposing them to be the hemispheres of 
 
86 
 
 the brain. After fishes come reptiles, then birds, 
 next, among mammiferous animals, the rodentia, 
 and in succession, the ruminantia, the carnivora, 
 the quadrumana and man.” 
 
 I have already shown, that in fishes generally, 
 the ganglions called optic, are disproportionate 
 in size to the nerves of vision ; and I have said 
 that part of these masses was, probably, destined 
 to other functions. The optic nerve of the carp 
 (pi. ii. fig. 4, 20) is smaller than that of the 
 roach (pi. ii. fig. 11, 20), but the so styled optic 
 ganglions (ib. n.) exist in these fishes in an in- 
 verse proportion. 
 
 “ The spinal marrow and the corpora quadri- 
 gemina,” says M. Serres in another place/ £ are 
 so rigorously developed in the ratio of each other 
 that the size .of the first being given in any class 
 or in any of its families, the volume of the latter 
 may be determined with precision,” 
 
 But the bigeminal tubercles in the carp (pi. 
 ii. fig. 5, n.) are much larger, in proportion to 
 the spinal cord, than in the eel (pi. ii. fig. 1) and 
 the roach (pi. ii. fig. 11.). M. Serres, himself, 
 has given representations of the optic apparatus 
 in the cassowary, ostrich, and other birds, much 
 larger in proportion to the spinal cord, than it is 
 in the many mammiferous animals whose brains 
 he has figured; and the disproportion between 
 the developement of the quadrigeminal bodies 
 
87 
 
 and spinal cord, is even greater in the dolphins 
 and porpoises, than in the ox, camel, and horse. 
 
 The most cursory glance over the physiology 
 of living beings also shows the utter erroneousness 
 of M. Serres’s position. Powers of voluntary 
 motion and of touch never bear any direct pro- 
 portion to the faculty of vision. The mole is, 
 certainly, far more remarkable for its muscular 
 strength than for its eye-sight, and the owl for its 
 powers of vision than for its bodily vigour. 
 
 I shall discuss the several relations which M. 
 Serres believes he has found between the quadri- 
 geminal bodies and other parts of the nervous 
 system, as I treat of these in succession. 
 
 M. Bailly, in his Memoir on the Comparative 
 Anatomy of the Nervous System in the four Classes 
 of Vertebral Animals, maintains that the corpora 
 quadrigemina anteriora et posteriora, the corpora 
 geniculata externa et interna are mere parts of the 
 optic lobe of inferior classes. He speaks of the 
 unfolding of the quadrigeminal bodies in fishes, 
 and of two systems of fibres very different from 
 each other: the one exterior and belonging to the 
 optic nerves ; the other interior, and being the ex- 
 pansion of a cord of the medulla oblongata. “ In 
 fishes and reptiles,” says he, “ the internal have 
 a much greater relative developement than the 
 external fibres ; in mammiferous animals, the ex- 
 ternal fibres alone remain ; the internal exist as 
 mere rudiments.” 
 
88 
 
 Dr. Gall* also says he is “ convinced that the 
 posterior pair of the corpora quadrigemina is a 
 ganglion, for the purpose of reinforcing or perfect- 
 ing the optic nerve.” He adds, “ the modes in 
 which these two pairs assist the function of vision 
 must differ, for they occur in various proportions 
 to each other, in the different species of animals ; 
 in some, indeed, the posterior two are scarcely 
 perceptible, or are even entirely wanting, although 
 vision be perfect, as happens in the case of birds.” 
 
 This diversity of opinion is to be accounted for, 
 by recalling to mind the delicacy of the cere- 
 bral organization, and the intimate connexion of 
 the parts with each other. When anatomists ob- 
 serve one or two parts connected together, they 
 very commonly conceive the one to be derived 
 from the other. By-and-by I shall treat, in a 
 separate section, of the communications of the 
 nervous masses, and of the importance of this 
 arrangement. Meantime, I shall pass my opinions 
 respecting the quadrigeminal bodies in review 
 before my reader. 
 
 The mammalia alone have quadrigeminal bo- 
 dies. Both pairs, however, have not, I conceive, 
 similar offices, for there is no proportion between 
 them indiscriminately, nor the bundles of fibres 
 which issue in different directions from each. The 
 fibres of the anterior pair, as I have said, join the 
 
 *Sur les Fonctions du Cerveau. — Ed. in 8vo. Vol. vi. p. 55. 
 
89 
 
 optic nerves, those of the posterior plunge under 
 the optic nerves, and are lost on the middle lobes 
 of the brain. The optic nerve communicates, by 
 means of superficial bands, with the posterior pair 
 of the quadrigeminal bodies, with the internal 
 and external geniculated bodies, with the mid- 
 dle and anterior cerebral lobes, and with the mass 
 called tuber cinereum. 
 
 Reptiles and birds have only one pair of rounded 
 tubercles, before and by the sides of the cere- 
 bellum. (PI. iii. fig. 2, 3, 4>, 5, 7, 10 and 11, n .) 
 These are readily seen, by throwing back the 
 cerebellum. On examining their structure, they 
 are found, in the first place, to be hollow (pi. 
 iii. fig. 9, side B. n.), and to detach a super- 
 ficial layer that communicates with the medulla 
 oblongata behind, and with the optic nerve and 
 base of the brain before ; and, in the second place, 
 to be connected by their lower parts with the 
 optic nerves and the cerebral crura or legs. This 
 structure of the optic ganglions in birds and rep. 
 tiles, corresponds to that of the anterior pair of 
 the quadrigeminal and external geniculated bo- 
 dies in mammiferous animals, as in them the one 
 and superficial layer of the anterior pair is con- 
 tinued into the optic nerve, whilst the other and 
 deeper is connected with the crura of the brain. 
 
 In fishes, the optic nerves always communicate 
 with the basis of the pair of tubercles that suc- 
 ceeds the cerebellum, and this pair is connected 
 
90 
 
 with the medulla oblongata ; but it and the optic 
 nerves have not, mutually, any regular or fixed 
 proportion, whilst the optic nerves and the rounded 
 tubercles that lie immediately behind their cross- 
 ing, are constantly developed in the ratio of each 
 other. The optic nerve, in fishes, moreover, com- 
 municates with the basis of the cerebral masses 
 that come after the cerebellum, precisely as it is 
 connected in the mammalia with the anterior and 
 middle lobes of the brain. 
 
 In proportion, therefore, as the cerebral masses 
 and fibrous bundles, or their successive additions, 
 diminish in number through the four classes of 
 vertebral animals, the primary optic ganglions 
 approach each other, and lie between or among 
 such cerebral parts as still exist; but as the brain 
 gets complicated, and vision exerts an important 
 influence upon its functions, the primary optic 
 ganglions lie backwards, in order that the appa- 
 ratus of vision may, conveniently, be brought 
 into communication with the cerebral parts whose 
 functions it especially aids. 
 
 Of the Olfactory Nerve , 
 
 Very different opinions have been, and are still 
 entertained by anatomists in regard to the origin 
 of the nerve of smell. Some of the moderns have 
 described it as arising from the masses called 
 striated bodies ; but there is no proportion, what- 
 
91 
 
 ever, between them and the nerve ; and further, 
 porpoises and dolphins have the striated bodies, 
 but no olfactory nerves. The nerves of smell 
 also exist in many acephalous monsters, whose 
 striated bodies are, of course, wanting. 
 
 The olfactory nerve, in the human kind, has 
 three roots ; of these, the interior (pi. vi. 21) is 
 the shortest, but broadest, and the exterior the 
 longest (ib. 18), for it extends to the bottom of 
 the fissure of Sylvius. These different roots are, 
 as it were, impacted in the cerebral substance ; 
 they approach by degrees, and having met, ad- 
 vance in the form of a single nervous trunk. In 
 man, the nerve parts from the anterior lobe at the 
 place where the convolutions commence, and runs 
 along the cleft formed between the innermost of 
 the anterior and inferior of these, accompanied 
 throughout its whole course by a very distinct 
 streak of cineritious substance. Immediately 
 above the cribriform plate of the ethmoid bone, it 
 encounters a considerable quantity of very soft 
 gray substance, with which it forms a sort of bulb. 
 (PI. vi. fig. 1, 23.) The nerve, here, gains a 
 mighty increase in size, and passing by numerous 
 filaments through the cribriform plate of the 
 ethmoid bone, it is lost upon the lining mem- 
 brane of the nose. 
 
 The olfactory nerve of monkies (pi. v. fig. 3), 
 and of seals, resembles that of man very nearly. 
 In the class mammalia, generally (pi. iv. fig. 2) 
 
92 
 
 a great many nervous fibres may be seen arising 
 from the anterior part of the middle cerebral lobe ; 
 these join the fibres that spring from the inferior 
 surface of the anterior convolutions, and compose 
 a broad and rounded band, which, remaining 
 attached to the anterior lobe, runs slightly inwards 
 until it arrives at the ethmoid bone, when, pre- 
 cisely, as in man, it meets a large mass of gray 
 substance (pi. iv. fig. 2, 3, and 4, 23), and in- 
 creases in size so much, that after its exit by the 
 ethmoidal holes, it suffices to cover the entire 
 surfaces of the large superior spongy bones. 
 
 The bulb that is formed over the ethmoid bone, 
 if it be incised, or have a piece taken out, will be 
 found to be hollow. Its internal white layer in 
 the lower animals communicates immediately with 
 the anterior cavity of the brain, so that by blow- 
 ing into the bulb of the olfactory nerve, the air 
 will penetrate and inflate the lateral ventricles. 
 Soemmerring says, that the olfactory nerve of the 
 human embryo, at an early period, is also hollow, 
 and that air blown into it reaches the cavities of 
 the brain. The same experiment will, occasion- 
 ally, though very rarely, succeed in the adult. 
 When we observe the olfactory nerve so very 
 large in the mammalia, whilst the mass of anterior 
 convolutions is but inconsiderable, and, on the 
 other hand, the nerve in the human kind so small 
 and surrounded by the thick masses of the ante- 
 rior lobe, we may conceive why the experiment 
 
93 
 
 should succeed so readily in animals, and be so 
 rarely practicable in man. 
 
 The olfactory nerve, it may be almost unne- 
 cessary to state, is proportionate in size to the 
 extent of external apparatus over which it is dis- 
 tributed. 
 
 In birds the nerve of smell is detached from 
 the anterior and inner part of the front lobe, but 
 its fibres are distinct from those of the brain ; 
 one of its bands too, which may be compared 
 with the external root of the same nerve in man, 
 runs towards the fissure of Sylvius and the middle 
 lobe. This band, however, is not equally appa- 
 rent in all birds. It is still less distinct in rep- 
 tiles. 
 
 In fishes the olfactory nerve arises by two very 
 distinct roots ; certain fibres of great delicacy 
 bring it into communication with the foremost 
 cerebral ganglions, and others of a firmer tex- 
 ture and whiter colour connect it with the lon- 
 gitudinal band, which, in these animals, lies in 
 the middle line between the various ganglions, 
 and communicates with the medulla oblongata. 
 (PI. ii. fig. 9 and 13.) 
 
 Some anatomists have considered the entire 
 mass of the anterior cerebral ganglion in the skate 
 (pi. ii. fig. 8, 1,2, 3), and all the three pairs of gan- 
 glions in the eel (pi. ii. fig. 1, 1, 2, 3), as des- 
 tined to originate the olfactory nerve. But the 
 error here committed is proclaimed by the fact 
 
94 
 
 of the origins being always in proportion to the 
 nerves themselves, and there being none what- 
 ever between the masses mentioned and the ol- 
 factory nerves of fishes. In regard to these gan- 
 glions, therefore, that which has been stated 
 respecting those of vision must be repeated : the 
 olfactory nerve is in communication with cere- 
 bral parts, destined to affective and intellectual 
 functions. 
 
95 
 
 Section IV. 
 
 Of the best Method of dissecting the Brain. 
 
 Before Dr. Gall and I began our researches on 
 the structure of the brain, anatomists, in their 
 dissections and descriptions, had no other object 
 in view than to know the forms of the whole, or 
 of its particular masses, the colours, connexions, 
 and consistency, of its individual parts. To at- 
 tain their end, they were in the habit of cutting 
 down the brain by slices, and examining and 
 noting the appearances presented by each in suc- 
 cession, until they arrived at the base. “ The 
 most accredited method, 5 ’ says M. Cuvier *, “ of 
 the schools, and usually recommended in books 
 of anatomy, is to take away successive slices of 
 the organ (the brain), and to remark the appear- 
 ances offered by each. This is the easiest in 
 practice for the demonstration, but it is the most 
 difficult for the imagination. The true relations 
 of parts, which are always seen cut across, escape 
 not the pupil alone, but the master himself.” 
 Willis f was the first who objected to the 
 
 * Rapport des Commissaires de l’lnstitut de France, on 
 our Memoir, entitled “ Recherches sur le Systeme Nerveux en 
 General, et sur le Cerveau en Particular.” 
 t Cerebri Anatomia. 
 
96 
 
 practice of considering, as distinct parts, all the 
 forms accidentally produced by such a mode of 
 dissection. He himself viewed the cerebral 
 parts in their connexions. He says too, that the 
 anatomical demonstration of the brain should be 
 begun at the basis ; by basis, however, let me 
 observe, he understood the striated bodies and 
 thalami. Ascending from these to the superior 
 parts, and returning on the inferior in succes- 
 sion, his attention was confined to the larger 
 masses, which he designates by names that indi- 
 cate physical qualities only. “ From the striated 
 bodies,” for example, he says, “ the legs of the 
 medulla oblongata are prolonged ; remaining 
 apart for a short way, they then approach and 
 get blended into a common stalk, composed, as 
 it were, of two peduncles or stems.” 
 
 As the Committee of the French Institute have 
 conceived themselves authorized to assimilate 
 the method of dissecting the brain, described in 
 our Memoir, with the plan pursued by Aarolius 
 and Yieussens, and have interpreted these au- 
 thors in a way which their language will not 
 bear, I hope it will not be found amiss, if I 
 extract a few passages from our Memoir, follow- 
 ing them by some observations on the report. 
 
 “ The brain,” say the Committee, “ is at- 
 tacked from below ; the medulla oblongata is 
 pursued across the bridge of Varolius, through 
 the thalami of the optic nerves, and the striated 
 
97 
 
 bodies, when its fibres expand and compose the 
 hemispheres. The hemispheres also, if we 
 choose, may, by tearing their lateral attachments 
 to the crura cerebri, be unfolded, the medulla 
 oblongata and cerebellum be split longitudinally, 
 and each half of the former shewn as a sort of 
 stem implanted into the hemisphere of its own 
 side, like the stalk of a mushroom into its cap.” 
 They add, “ It is probable that this method 
 would have had more vogue, were it not ex- 
 pressed in a rude drawing by Varolius, and had 
 not the work of Vieussens remained, it would be 
 difficult to say wherefore, in a sort of discredit, 
 which it by no means deserves.” 
 
 In reply to this we cite the following passages, 
 from the works of the two authors mentioned 
 above *. “ The generality of anatomists,” says 
 
 Varolius, “ think the spinal marrow begins at 
 the occipital hole only ; I can bring proof to the 
 contrary. It arises on the one hand below the 
 ventricles of the brain, and on the other from 
 the middle and inferior part of the cerebral basis. 
 In the same manner as the brain, from out its 
 substance, first produces that considerable trunk, 
 the spinal marrow, from which the ocular nerves 
 soon arise ; in the same manner the cerebellum 
 pushes from itself a considerable process, which 
 
 * Constantii Varolii Anatomicse, sive de Resolutione 
 Corporis Humani Libri Quatuor. Frankforti, 1591 ; and, Vieus-* 
 senius, Neurographia Universalis. 
 
 H 
 
98 
 
 I call bridge of the cerebellum, out of which the 
 auditory nerves then issue “ That the sense 
 of touch may inhere in all parts, and that all 
 parts may convey images of objects, cognized 
 by touch, to the primary sensorium, there are 
 four roots issuing from the brain and cerebellum 
 to form a considerable trunk, the spinal marrow, 
 from which nerves are sent off and distributed 
 to every part of the body f.” “ For my part, 
 
 seeing that there were several cerebral organs 
 situated about the base of the head, and that the 
 brain by its weight (especially in the dead) 
 compressed these against the skull, I deemed the 
 ordinary mode of dissection liable to many in- 
 conveniences. This is the reason why I am in 
 the habit of commencing the dissection at the 
 opposite part of the head ; that is to say, at the 
 basis of the brain, and by so doing, each of its 
 organs is so clearly exhibited, that it seems as if 
 nothing further could be desired. This method, 
 however, which differs from the usual one, is 
 also very difficulty.” Let any one read Varo- 
 lius’s letter to Mercurialis, and he will be con- 
 vinced, from his entire description, that he con- 
 fined himself to the various forms and appear- 
 ances visible in the brain and cerebellum ; that 
 he did no more than attack the brain mechani- 
 cally, turning and returning it without order or 
 
 * Varolius, p. 26. 
 
 f Ibid. p. 36. + Ibid. p. 140. 
 
99 
 
 method, going from the cerebellum to the optic 
 and olfactory nerves, and from the optic and ol- 
 factory nerves coming back to the cerebellum. 
 Let me add, that Varolius himself says, that the 
 mass he calls spinal marrow is comprised be- 
 tween the annular protuberance and the cere- 
 bral hemispheres ; and further, that he conti- 
 nually speaks of the spinal cord as a production 
 of the brain. What the Committee of the French 
 Institute make Varolius say, consequently, is not 
 to be found in his works. 
 
 Let us now turn to and review the method of 
 dissection practised by Vieussens, which, ac- 
 cording to the Committee of the French Insti- 
 tute, is “ the same that Varolius employed, but with 
 greater order a?id details In his first thirteen plates 
 he shews nothing but sections of the brain from 
 above downwards. He begins his demonstration 
 with the convex part of the hemispheres, and then 
 passes to the corpus callosum. The better to 
 expose this, he cuts off the entire superimposed 
 hemispheres by a horizontal sweep, and then by 
 properly trimming the mass that is left, he forms, 
 what he calls, the centrum orale, in which he 
 concentrates all the medullary fibres that, ac- 
 cording to him, arise from the cortical sub- 
 stance of the brain, and from which he makes 
 nervous fibres descend to every part of the body. 
 He then passes on to the transparent partition 
 
 (valvula Vieussenii), that has since gone by his 
 
 H 2 
 
100 
 
 name, to the fornix, to the choroid plexus, to the 
 nates, to the testes, &c. &c. 
 
 “ We have,” he says, in one place expressly, 
 “ explained in a clear and complete manner, all 
 that concerns the superior part of the brain and 
 medulla oblongata; we have also examined the 
 cerebellum externally and internally; we have 
 only then, following the order of dissection which 
 we have adopted, to examine what is found without 
 and within the basis of the brain, properly so 
 called, and the spinal marrow.” 
 
 “ After the exact explanation,” he proceeds, 
 “ of all that is to be seen on the upper part of the 
 brain and spinal marrow, or that belongs to the 
 cerebellum, in order to find with ease, and to 
 describe with care that which is found at the 
 basis of the brain, properly so called, and of the 
 spinal marrow, we take away the cerebellum by 
 cutting its peduncles transversely, and turn over 
 the brain, freed from its convex parts by partial 
 sections, and then Ave show the divided trunks 
 of the anterior arteries of the base of the brain — 
 the ten pairs of nerves — the infundibulum — the 
 two white prominences situated near the infun- 
 dibulum — the two processes of the cerebellum 
 towards the medulla oblongata, which run into 
 the major annular protuberance of Willis — the 
 pyramidal bodies — the olivary bodies — and the 
 spinal nerves which join the par vagum.” 
 
 It was always from his oval centre that Yieus- 
 
101 
 
 sens began his sections and descriptions of the 
 brain. His principles, indeed, did not permit him 
 to follow any other method of demonstration. 
 
 In our answer to the Committee of the Institute, 
 Dr. Gall and I have gone more deeply into de- 
 tails ; but the passages cited above will suffice to 
 shew that the methods of Varolius and Vieussens 
 are directly opposed to our manner of dissecting 
 and considering the brain and its parts. Vieussens, 
 in deriving all the nervous fibres from his oval 
 centre, proves himself to have had no idea of the 
 successive reinforcement of the cerebral masses. 
 I may, indeed, say generally, that an examination 
 of all the anatomical works published before our 
 time, and an inquiry into the various modes in 
 which the brain has been dissected, whether in 
 public or in private schools, will not fail to con- 
 vince every candid mind that there is not even a 
 hint at the anatomico-phvsiological views which 
 we have given to the world. These views some 
 modern anatomists have adopted, but we still ad- 
 vance our claim of right to be considered as the 
 discoverers and introducers of a new method of 
 dissecting the brain — as the first demonstrators 
 of the anatomy of its masses in harmony with 
 their physiology. 
 
 What, then, is our mode of investigating the 
 structure of the various cerebral masses? I have 
 already shewn (in the preceding section), that we 
 consider the nerves commonly entitled cerebral. 
 
102 
 
 as independent of each other, and that we regard 
 the masses of the cerebellum, and brain, properly 
 so called, as added to the nerves of the five 
 senses and of voluntary motion. This point of doc- 
 trine established, we view the brain not as an unit 
 or single organ, but as an assemblage of particular 
 apparatuses destined to special and determinate 
 functions, after the manner of the nerves of the 
 external senses. 
 
 To this it may be said, that several anatomists 
 have spoken of many peculiar parts, that they 
 have even designated these by appropriate names, 
 consequently, that our ideas on the plurality of 
 apparatus are not new. 
 
 There is no doubt whatever, but that all anato- 
 mists have recognised distinct parts in the brain, 
 and given them names according to their physical 
 qualities. They have found hemispheres, convolu- 
 tions, cavities, striated bodies, pea-shaped bodies, 
 stalks or legs of the brain and cerebellum, writing 
 pens, rams’-horns, semicircular tape-worms, pyra- 
 midal and olive-like bodies, &c., &c. Now we, 
 in shewing that the individual masses, so named, 
 do by no means constitute special apparatuses, 
 performing peculiar functions, differ from all the 
 anatomists who have gone before us. We were, 
 also, the first to prove the relative proportions that 
 exist between several of the cerebral masses, and 
 to examine them in their mutual relations. If I 
 continue to make use of the mechanical nomen- 
 
103 
 
 clature, to speak of parts in particular, which can 
 no longer be considered as special apparatuses, 
 it is only for the sake of being more readily un- 
 derstood. My connected description will shew 
 what masses I look upon as peculiar organs. 
 
 Our physiological views do not, it must be 
 evident, allow us to go on cutting the brain into 
 slices ; this procedure, indeed, ought rather to be 
 entitled a destruction, than an anatomical demon- 
 stration of the cerebral structure ; it is precisely 
 as though one should pretend to dissect a leg or an 
 arm, by slicing down these members transversely, 
 or to shew the structure of the thoracic and abdo- 
 minal viscera, by treating the trunk in a similar 
 manner, and giving names to the appearances 
 exposed after each successive slice. We commence 
 our dissection at the place where the proper cere- 
 bral masses are added to the nervous parts already 
 described; we trace them in their continuations, 
 and in their connexions mutually, and with the 
 nerves of the five senses and of voluntary motion; 
 in short, we proceed in the dissection of the brain 
 in a manner precisely analogous to that which is 
 followed in the anatomical demonstration of the 
 other parts of the body. 
 
 Besides the above general anatomical principle 
 as regards procedure, it is important to know that 
 on account of their extremely delicate organiza- 
 tion, the structure of several cerebral parts may 
 
104 
 
 be more easily and clearly exposed by means of 
 scraping than by cutting. This is the reason why 
 I frequently prefer the handle to the blade of 
 the scalpel for removing parts that cover those 
 whose course I would shew, — for instance, the 
 passage of the pyramidal bodies across the annular 
 protuberance — the continuation of the anterior 
 commissure through the striated bodies into the 
 middle lobes of the brain, and of the anterior 
 pillars of the fornix, onwards to the mammillary 
 bodies and interior of the thalami. 
 
 The brain should be removed from the cranium, 
 care being taken not to tear the crura at the 
 superior edge of the annular protuberance, (an 
 accident that is very apt to occur,) nor to injure 
 the medulla oblongata at the lower edge of the 
 same part, and to cut the spinal mass so low 
 down as to obtain, besides the entire medulla 
 oblongata, the upper part of the true spinal cord. 
 The brain thus freed from the skull, is then to be 
 put into a plate, with the basis uppermost. The 
 cerebellum and medulla oblongata having lost 
 the support of the bone, now fall backwards. 
 (PI. vii. fig. 1.) In this position, all the appear- 
 ances presented by the base of the brain are 
 visible. Having considered the cranial nerves in 
 the manner described in the preceding section, 
 the structure of the true cerebral masses is to be 
 examined, commencing with that of the cerebel- 
 
105 
 
 lum. As I treat of the several parts, I shall 
 always indicate the procedure that appears to me 
 the most convenient for exhibiting their ana- 
 tomy *. 
 
 * The method of dissecting the brain which M. Laurencet of 
 Lyons proposes, seems founded on imaginary notions, rather 
 than on the observance of nature and fact. According to him, 
 the nervous system is like two trees reversed, the branches of 
 the one being continuous with the roots of the other, or after the 
 manner of the sanguiferous system. The spinal cord, he says, 
 consists of four bundles, which, in the medulla oblongata, are 
 the anterior and posterior pyramids. The anterior, after their 
 decussation, he supposes to continue across the pons Varolii, 
 the crura cerebri and corpora striata, towards the corpus callo- 
 sum and the convolutions, from thence to the fornix, to the 
 thalami, corpora quadrigemina, cerebellum and posterior pyra- 
 mids. The number of nervous fibres is assumed to be every- 
 where the same ; there are only bulgings and contractions in 
 succession. M. Laurencet cuts the parts, and then tells us how 
 they are formed. 
 
106 
 
 Section V. 
 
 Of the Cerebellum. 
 
 To avoid all risk of confusion, I repeat once 
 more that I separate the nervous mass of the 
 spine and the cranial nerves from the brain, and 
 that I confine this last appellation to the entire 
 nervous mass, added to the nerves of the external 
 senses and of voluntary motion. I also repeat that 
 the first anatomical principle of the nervous sys- 
 tem, generally, applies to the brain in particular, 
 that is to say, this mass is not a simple unit, but 
 a collection of many peculiar instruments. As this 
 proposition is of great importance, I shall examine 
 it here at some length. It is to be established by 
 anatomy, physiology, and pathology. The phy- 
 siological and pathological proofs of its truth, are 
 contained in the second section of my Work 
 on Phrenology, wherein I treat of the plurality 
 of the organs. In this place, consequently, I 
 shall confine myself to illustrative anatomical 
 considerations. 
 
 That the cerebral parts are more or less nume- 
 rous in different tribes of animals, is a fact which 
 cannot be gainsaid. Many writers, among others, 
 Dr. Gall*, say that the faculties of animals are 
 
 * Anat. et Phys. du Cerveau, t. iii. p. 364. 
 
107 
 
 multiplied in proportion as their brains are complicated. 
 Were this remark universally correct, it would 
 serve as a positive proof of the brain’s being an 
 assemblage of organs. But without reckoning the 
 difficulty, not to say the impossibility of deter- 
 mining, anatomically, even in birds and mammi- 
 ferous animals, the constituent parts of the brain, 
 and admitting that as true which mechanical ana- 
 tomy demonstrates, viz . : — that the brain is made 
 up of a greater or smaller number of bundles, it 
 must still be observed that each particular bundle 
 cannot, legitimately, be assumed as composing a 
 peculiar organ. There are several cerebral masses 
 which, although more or less compound, do not, 
 therefore, cease to be mere units. Take the cere- 
 bellum as an example. This is extremely simple 
 in fishes, and very complicated in man, neverthe- 
 less it is but a single instrument in both. The same 
 law applies to several other cerebral parts, which, 
 although exceedingly complex, only compose the 
 instrument of a single function. Thus the first 
 fact showing the structure to be more or less 
 complicated, is no satisfactory or conclusive evi- 
 dence as to the plurality of the cerebral organs — 
 this induction is still only problematical. 
 
 Dr. Gall derives another anatomical proof of 
 the principle under discussion, from the analogy 
 that subsists between the organization of the 
 brain and that of the other nervous systems. 
 This analogy, however, is very limited. The 
 
108 
 
 spinal cord affords no example of it. Although 
 composed of many parts, or numerous pairs of 
 nerves, its functions are but repetitions of two of 
 different kinds: viz . , sensation and motion. But 
 the particular organs of the brain must be as 
 distinct as the acoustic, optic, and olfactory 
 nerves. 
 
 A better anatomical illustration follows from 
 the fact of all parts of the brain not being de- 
 veloped simultaneously, and of their volumes 
 severally bearing no regular proportion to each 
 other. The size of the cerebellum, for instance, 
 is not in any direct ratio to that of the brain, 
 neither are the three lobes of the cerebral he- 
 mispheres proportionate to each other. The 
 same law applies in regard to all the individual 
 parts of these lobes. 
 
 These proofs, founded on the non-simultaneous 
 development and non-proportionate volume of 
 the individual portions of the encephalon, are 
 strengthened by facts, which shew that the cere- 
 bral parts may severally be wanting. M. Jade- 
 lot was so kind as to shew Dr. Gall and me an 
 hydrocephalic child, in the Hopital des Enfants 
 Malades, at Paris, many of the superior convo- 
 lutions of both hemispheres of whose brain were 
 wanting, so that there was a hole communicating 
 on each side with the lateral ventricles. The 
 edges of these holes were smooth, and all the 
 appearances bespoke a congenate or primary de- 
 
109 
 
 feet of organization. The brain, of which a 
 drawing is given in pi. v. fig. 5 and 6, belonged 
 to a girl, who died, aged seventeen, and was 
 idiotic from birth. She died in the asylum at 
 Cork. Dr. Abell, of that town, and Dr. Cheyne, 
 of Dublin, had the goodness to send me the na- 
 tural skull, and casts, in plaster, of the brain 
 and bust. A comparison of this brain with one 
 of a healthy and well-constituted individual (pi. 
 vi. fig. 1 and 2), will show its anterior lobes to 
 be exceedingly deficient, and the convolutions 
 that commonly exist in the upper region of the 
 forehead to be wanting altogether. It is even 
 less complicated, and more poorly developed, 
 especially anteriorly, than the brain of the ourang- 
 outang. (PI. v. fig. 8 and 4.) Mr. Stanley, of 
 London, preserves a similar idiotic brain in 
 spirits. 
 
 The anatomical evidence, from the want of pro- 
 portion among, and the non-simultaneous develop- 
 ment and entire absence of, the cerebral parts, 
 although plausible, is not, however, decisive in 
 proving the plurality of the organs. The tes- 
 timony these facts supply only becomes conclu- 
 sive, when they are united to physiology. Alone, 
 they do not prove that the functions of the 
 parts, whose development is neither simulta- 
 neous nor proportionate, and Avhich, individually, 
 may be wanting, are dissimilar. — The branches 
 of a tree shoot in succession, yet all bear the 
 
110 
 
 same [fruit. But those cerebral parts are indu- 
 bitably the same, however dissimilar in physical 
 appearance, if like functions appear with their 
 presence, increase with their growth, are vigorous 
 in proportion to their masses, and wanting with 
 their absence. Cerebral parts, on the other hand, 
 differ if like functions do not appear with 
 their development, be not manifested in vigour 
 corresponding to their volumes, and exist or not 
 independently of their presence or absence. 
 
 Certain it is, therefore, that liow important so- 
 ever it may be to classify the cerebral organs, 
 anatomy alone would never enable us to attain 
 such a consummation. The aid of physiology 
 is indispensably requisite. Now Dr. Gall and I 
 claim the merit of having been the first to com- 
 pare the relations between the development of 
 different cerebral parts and peculiar functions ; 
 and our physiological anatomy of the brain 
 proves, that the parts indicated in books of 
 descriptive anatomy as distinct masses, such, for 
 instance, as those styled pons or bridge, pyrami- 
 dal and olive-like bodies, thalami, mammillary 
 bodies, callous or hard body, &c. & c., do not 
 constitute particular organs. 
 
 Some anatomists have expressed doubts as to 
 the possibility of proving the presence or ab- 
 sence of individual parts in the human brain, 
 especially in the hemispheres and their convolu- 
 tions ; because, say they, the physical appear- 
 
Ill 
 
 ance of these is not invariable. But, provided 
 essentials be not confounded with modifications, 
 the very reverse of the above assumption may 
 easily be proved. The lobes are always to be 
 distinguished from one another, and certain con- 
 volutions from others, with the same certainty 
 as the annular protuberance is to be discrimi- 
 nated from the crura of the brain, the quadrige- 
 minal from the mammillary, and the pyramidal 
 from the restiform or olive-like bodies. The ge- 
 neral form and direction of the convolutions, even 
 of the human brain in its complication, are, in 
 fact, remarkably regular. Thus, the transverse 
 convolutions of the superior lateral and middle 
 parts of the hemispheres are never found run- 
 ning in any other direction, never longitudinally 
 for example. Those that lie longitudinally again, 
 as they do under the squamous suture, behind 
 the temporal bone, and on either side of the ol- 
 factory nerve, are never met with disposed trans- 
 versely. 
 
 “ Shew Gall,” says Dr. Rudolphi *, “ the or- 
 gans of theft, of murder, and of the religious 
 sentiment separated from the cerebral mass, and 
 be sure he would not know them.” Dr. Gallf, 
 in his reply to this, contents himself with say- 
 ing, <c Shew M, Rudolphi morsels of the spinal 
 
 * Physiologie, ii. Band, Berlin, 1823. 
 t Sur les Fonctions du Cerveau, tom. vi. p. 138. 
 
112 
 
 marrow or medulla oblongata, and be sure he 
 would not know them; yet are the spinal mar- 
 row and medulla oblongata proved to be aggre- 
 gates of different nerves.” This answer of 
 Dr. Gall does not satisfy me. In the first place, 
 I have shewn the brain to be composed of many 
 parts, whose functions are essentially different, 
 whilst all the portions of the spinal cord have 
 similar offices. Dr. Gall’s reply, therefore, is 
 simply evasive. But, for my part, I will accept 
 M. Rudolphi’s proposition directly ; for I main- 
 tain that he who has studied the forms of the 
 peripheral expansions of the cerebral organs, 
 will always be able to distinguish, in man, the 
 organ of acquisitivenes from that of destruc- 
 tiveness, and that of veneration from either, (the 
 organs of theft, murder, and the sentiment of 
 religion, in M. Rudolphi’s nomenclature,) as easily 
 as an ordinary observer will the olfactory from 
 the optic nerve. I am ready at any time, per- 
 sonally, to verify the above statement. 
 
 However, I still admit, that the convolutions 
 forming parts of any particular apparatus, pre- 
 sent many modifications in reference to size and 
 number of anfractuosities. Such modifications 
 occur, not only in the brains of different indivi- 
 duals, but even in the two hemispheres of the 
 same brain. Variety, however, need not be 
 confounded with essential configuration. I have 
 
113 
 
 remarked, that the organs which are best nou- 
 rished, and most largely developed, have gene- 
 rally the smallest number of anfraetuosities. 
 
 The importance of classing the cerebral organs 
 is, as I have said, evident. Researches to this 
 end interest the anatomist, the physiologist, and, 
 above all, the practical physician, on account of 
 the brain’s influence on the vegetative functions, 
 on the origin, duration, character, and cure of a 
 long list of diseases, especially of such as de- 
 pend on moral causes. To render such inquiries 
 complete, they must be extended into compara- 
 tive anatomy, always in the view of proving the 
 brain to be an assemblage of organs, destined to 
 dissimilar functions, mutually in relation, liable 
 to disease severally, and likewise to derange each 
 other reciprocally. 
 
 To compare the spinal cord, and even the cra- 
 nial nerves, in the different classes of vertebral 
 animals, is by no means a very arduous task. But 
 to do the like in regard to the brain is one of ex- 
 treme difficulty. Anatomists commonly set out 
 with the human brain in their eye as a type of 
 comparison ; this they consider as an unit hav- 
 ing two hemispheres, a corpus callosum, an an- 
 terior, middle, and posterior commissure, an 
 infundibulum, fornix, feet of a hippocampus, 
 mammillary bodies, striated bodies, optic tha- 
 lami, a semicircular tenia or tape-worm, quadri- 
 geminal bodies, crura or legs, a valve of Yieus- 
 
 i 
 
114 
 
 sens, a pons, bridge, or annular protuberance, a 
 cerebellum, having also crura or legs, a medulla 
 oblongata, pyramidal, olivary, and restiform bo- 
 dies, four ventricles, an aqueduct styled of Syl- 
 vius, and several other parts : and then they 
 proceed to recognise or deny the existence of 
 parts according to mere physical appearances, 
 especially forms and situations. 
 
 Such a mode of proceeding, however, is quite 
 inadequate to establish a system of comparative 
 cerebral anatomy. The brain, in the first place, 
 is not an unit, but an assemblage of particular 
 apparatuses, that require severally to be specified ; 
 and again, it is certain that the isolated masses, 
 such as they are described in books of anatomy, 
 do not constitute peculiar organs, but that several 
 of them, indeed, sometimes go to the formation 
 of one. The cerebellum is found, either with or 
 without an annular protuberance; the anterior 
 pyramidal bodies are not one organ, but consist 
 of parts of many; they are, in fact, the rudiments 
 of the organs of the intellectual faculties. And 
 further, the physical appearance of apparatuses 
 which are known to have analogous functions, is 
 often exceedingly different. Without knowing 
 the functions of the cerebral parts, it is, therefore, 
 impossible to demonstrate either their identity 
 or their difference. What anatomist, unacquainted 
 with the function of smell, w T ould ever have con- 
 cluded that the olfactory nerves of the skate. 
 
115 
 
 flounder, chicken, seal, ox, and man, were analo- 
 gous masses? Certainly, similarity of appearance 
 would never have led to the conclusion ; and dif- 
 ferences in appearance among the other cerebral 
 masses, are not less remarkable than in the olfac- 
 tory nerve throughout the four classes of vertebral 
 animals. Thus, I conceive that the comparative 
 anatomy of the brain can neither be itself ad 
 vanced, nor afford satisfactory conclusions with- 
 out the aid of physiology. 
 
 The common and objectionable manner of ex- 
 amining the structure of the encephalon, led 
 anatomists to conclude that they had discovered 
 the same cerebral masses in the mammalia as in 
 man, and, because the forms of the parts were 
 different, to deny their existence in birds and the 
 inferior classes of animals. In all the lower tribes 
 of creation, they supposed another and a different 
 composition of the encephalon. 
 
 I claim the merit of having been the first to 
 maintain that the analogy or difference of cere- 
 bral parts, in different classes, ought to be de- 
 termined by the combined aid of anatomy and 
 physiology. I have no hesitation in saying that 
 the relations of the cerebral masses, as they are 
 indicated by M. Serres in his prize memoir, are 
 very far from having replied in a satisfactory man- 
 ner to the question propose d by the Institute of 
 France. I also think it ma.y not be out of place 
 to state that Baron Cuvier, perpetual secretary to 
 
 12 
 
116 
 
 the physical class of the French Institute, in his 
 analysis of the academy’s labours for the year 
 1820, has mentioned the name of Dr. Gall in re- 
 ference to two points only, on which M. Serres 
 differs with the Doctor, whilst he reports se- 
 veral other and important facts and views, dis- 
 covered by me, and published conjointly with 
 Dr. Gall, as forming part of the memoir of M, 
 Serres; such, for instance, as the relation between 
 the annular protuberance and the lateral parts of 
 the cerebellum, and that between the corpus 
 callosum and the cerebral hemispheres. 
 
 In admitting as an anatomico-physiological 
 principle, that the particular organs of the cerebral 
 functions bear no proportion relatively, in the 
 same way as the instruments of the external 
 senses are in no direct ratio one to another, I 
 deny generally, as I have already done particu- 
 larly, in regard to the spinal cord, the proposi- 
 tion of M. Serres, according to which, “ the tuber- 
 cula quadrigemina serve as a basis of determination to 
 the other parts of the encephalon * The quadrige- 
 minal bodies do, in nowise, bear any direct pro- 
 portion to the anterior, middle, and posterior lobes 
 of the brain. These masses exist independently 
 of each other, and belong to apparatuses that are 
 totally distinct. The quadrigeminal tubercles are 
 
 * “ Les tubercules quadrigeminaux servent de base de deter- 
 mination aux autres parties de l’Encepbale,” Rapport, &c., 
 p. 67 ; and Serres’s Anatomie, &c. vol. 1 , Preface. 
 
117 
 
 absolutely smaller in man and the dog, than in 
 the horse and ox, but the brain of the animals 
 last mentioned is larger than that of the dog, and 
 smaller than that of man. Each special apparatus 
 must be determined by itself, and by comparison 
 with its particular function. 
 
 In many fishes there are portions of gray ner- 
 vous substance to be observed, forming ganglions 
 on the lateral edges of the medulla oblongata. (PI. 
 ii. fig. 3, 5, 12, 13, e .) By removing the cerebel- 
 lum, a ganglion may, in many species, be seen in 
 the middle line (pi. ii. fig. 13, 43); this ganglion 
 is, sometimes, naturally exposed. (PI. ii. fig. 5, 
 43). All these masses pertain to the nerves that 
 issue from them. 
 
 The nervous mass immediately succeeding 
 these ganglia, is the first cerebral apparatus; it is 
 distinguished by the name of cerebellum, and ex- 
 ists in all vertebral animals lying on the dorsal sur- 
 face of the medulla oblongata. Its name is de- 
 rived from the anatomy of man, in whom the corre- 
 sponding mass is smaller than the brain, properly 
 so called. This example, among many others that 
 might be cited, proves how defective that nomen- 
 clature of the encephalon is, which is founded 
 on the physical qualities of the human brain. Is it 
 not astonishing that anatomists, who deny to fishes 
 a cereberum or brain, should still acknowledge 
 them possessed of a cerebellum or little brain? 
 Let me, therefore, repeat, that a good nomencla- 
 ture should have for its basis the nature of the 
 
118 
 
 functions performed by the particular instruments. 
 My only reasons, as I have said already, for con- 
 tinuing to use the old and faulty names, is to 
 make myself understood more readily. 
 
 The cerebellum or organ of amativeness, is com- 
 plicated in different degrees in the four classes of 
 vertebral animals ; its form and its volume vary 
 exceedingly, but it regularly communicates pos- 
 teriorly with the nervous mass of the spine on 
 either side, and anteriorly with the bigeminal or 
 quadrigeminal bodies. 
 
 “ To acquire accurate notions of the cerebellum 
 in the superior classes,” says M. Cuvier, “ accord- 
 ing to M. Serres, they must, in the first instance, 
 be taken from fishes. In these animals, this or- 
 gan is formed of two very distinct parts — a middle 
 lobule deriving its roots from the ventricle of the 
 quadrigeminal tubercles, and two lateral portions 
 coming from the restiform bodies; the two parts 
 are insolated and disjunct in the whole of the 
 class pisces, a circumstance that has occasioned 
 them to be mistaken*.” 
 
 Now this fact is not, by any means, so general 
 
 * “ Pour avoir des notions exactes surles cervelets des classes 
 supferieures d’apresle Memoire de M. Serres, il faut d’abord les 
 emprunter aux poissons. — Chez les poissons cet organe est 
 forme de deux parties tres distinctes: d’un lobule median, preuant 
 ses racines dans le ventricule des tubercules quadrigeminaux, et 
 de feuillets lateraux provenant du corps restiforme : les deux 
 parties sont isolees, disjointes dans toute la classe des poissons 
 ce qui les avail fait meconnaitre .” — Rapport des Travaux de la 
 Classe Physique pendant VAnnte 1820, p. 67. 
 
119 
 
 as M. Serres would have us suppose. What are 
 his reasons, let me ask, in the first place, for class- 
 ing the ganglion 1 have just pointed out as 
 situated in the fourth ventricle (pi. ii. fig. 5 and 
 13, 43), along with the cerebellum? — He can have 
 none. And again, in the eel (pi. ii. fig. 1) — in the 
 cod (pi. ii. fig. 2) — in the flounder (pi. ii. fig. 7) 
 — in the roach (ib. fig. 11), and many others, the 
 surface of the cerebellum is quite smooth. In the 
 skate, on the contrary, it is evidently composed 
 of several ramifications. (PI. ii. fig. 3.) 
 
 In fishes, generally, there is a bundle which, 
 with its fellow of the opposite side, forms a hollow 
 mass stretched above the fourth ventricle, and 
 covered on its peripheral surface with gray sub- 
 stance. It is, for the most part, loose at one ex- 
 tremity only; it has either a pointed, a rounded, 
 or a flattened form, and is most commonly turned 
 towards the back. In the skate, however, it has 
 two loose extremities, the one pointing forwards, 
 the other backwards. 
 
 Reptiles, in general, have a cerebellum, com- 
 posed of two parts, which are hollow, superficially 
 smooth, and in communication with each side of 
 the medulla oblongata. In some of the class, it is 
 extremely small, as in the toad and frog (pi. iii. 
 fig. 2), which, in this respect, resemble the stur- 
 geon among fishes; in other reptiles, however, 
 and of the number is the crocodile, the cerebel- 
 lum, as in the skate and shark, is furrowed on the 
 
120 
 
 surface, and bears marks of a more complicated 
 structure. 
 
 The ramified and lamellar structure of the ce- 
 rebellum (pi. iii. fig. 5, 6, 7, 9, 10, and 11), and 
 its division into median and lateral portions, 
 become very evident and regular in birds and 
 mammiferous animals. In birds (pi. iii. fig. 5, 7, 
 10, and 11), the middle or primary portion is 
 large compared with the lateral parts. These, 
 indeed, are scarcely evolved in the class aves, 
 they, however, become ever more remarkable in 
 size and number^ of ramifications, in proportion 
 as we mount from the lowest up to the highest of 
 the mammiferous tribes and reach man. In the 
 foetus, the cerebellum, even of those animals in 
 which it afterwards presents numerous convolu- 
 tions, is always quite smooth. The primary por- 
 tion of the cerebellum, in all birds, is divided into 
 several branches ; the middle and upper one of 
 these is the most remarkable. Below and in front 
 of the fourth ventricle, in the same class, there 
 occurs a little lobule, the volume of which, like 
 that of the lateral parts, is much augmented in the 
 mammalia. These peculiarities of structure prove 
 that oviparous animals, in general, cannot be said 
 to have a simple cerebellum. 
 
 The cerebellum of fishes, of reptiles, and of 
 birds (pi. xi. fig. 3, 62), is constantly hollow. 
 Its cavity communicates with the fourth ventricle 
 (ib. m), or space between the cerebellum and 
 
121 
 
 medulla oblongata. The cerebellum of the mam- 
 malia is, on the other hand, invariably solid ; the 
 fourth ventricle is the only cavity in its vicinity. 
 (PI. xi. fig. 1, m.) 
 
 The anatomical principle laid down in regard 
 to the regularity of proportion, between the cine- 
 ritious and white substances, and to the occur- 
 rence of cineritious matter at the origins of ner- 
 vous masses, is confirmed by the structure of the 
 cerebellum. At the place of this organ’s attach- 
 ment to the medulla oblongata, there is always 
 an accumulation of pulpy substance to a greater 
 or smaller amount ; that is to say, the quantity 
 is great, or small, relatively to the volume of 
 the entire cerebellum. In man it composes an 
 irregularly-shaped mass, toothed or serrated 
 around the edges. This collection of cineritious 
 intermixed with white matter, is described in 
 books of anatomy under various names, such as 
 corpus rhomboideum, corpus dentatum, zig-zag, 
 and kernel of the cerebellum. I speak of it un- 
 der the title of ganglion of the cerebellum. 
 
 Vicq d’Azyr believed that the ganglion of 
 the cerebellum was only to be found in the hu- 
 man kind. But in 1808, conjointly with Dr. Gall, I 
 shewed that it exists in the mammalia generally * ; 
 and I now add, that it is very distinct in birds. 
 Whenever the cerebellum is somewhat consi- 
 derable, it may always be demonstrated. Its 
 * Vid Memoire sur l’Anatomie du Cerveau, &c. 
 
122 
 
 small size and pale colour were probably the 
 causes of its existence being overlooked. But it 
 is matter of prime importance not to confound 
 the forms assumed, and the lighter or deeper 
 shades of colour possessed by the pulpy sub- 
 stance, with its necessary existence. 
 
 The quantity of cineritious substance at the 
 origin of the cerebellum is in the direct ratio of 
 the entire mass, and not merely of the lateral 
 parts of that organ. It is very conspicuous in 
 birds, although the lateral parts of their cere- 
 bella be but rudimentary. In man too, a portion 
 of the ganglion may easily be demonstrated run- 
 ning towards the vermiform process (the pri- 
 mary part) of the cerebellum. 
 
 From what I have said, it follows that this 
 ganglion is not situated in the middle of the ce- 
 rebellum, but commences where this mass is 
 connected with the medulla oblongata. Yicq 
 d’Azyr commits a capital error in his plate xxxi. 
 fig. 20, in representing the ganglion of the cere- 
 bellum as placed so much externally, so near to 
 the anterior edge of the organ to which it be- 
 longs, and so far distant from the medulla ob- 
 longata. 
 
 In forming the cerebellum, nature has, in all 
 animals, pursued the same plan. Two bundles 
 constantly bring it into connexion with the two 
 sides of the medulla oblongata ; these are of va- 
 riable size ; they meet a greater or smaller quan- 
 
123 
 
 tity of gray substance, and proceed strengthened 
 in proportion to the quantity of this substance 
 encountered ; they then regularly compose a pri- 
 mary portion, which in the lowest tribes is smooth 
 superficially, but which, as the scale is mounted 
 in, appears furrowed transversely, or divided 
 into lamellae, and gets complicated by the addi- 
 tion of lateral masses, laminated in like manner. 
 This lamellar structure is exposed by a vertical 
 cut through the cerebellum ; it bears the name 
 of arbor vitae, on account of its supposed re- 
 semblance to the foliage of the thuya, or tree of 
 life. (PI. viii. and ix. fig. 1 and 2.) 
 
 Although the human cerebellum be very com- 
 plicated, the elements of a precisely similar for- 
 mation to that of the lower animals, may without 
 difficulty be traced. One slip from the ganglion 
 forms with its fellow of the opposite side the 
 vermiform process, or primary portion, which by 
 a cut carried through the middle line, may be 
 seen afterwards dividing commonly into seven 
 principal parts. (PI. vii. fig. 2, and pi. x. fig. 1, 
 and pi. xi. fig. 1. A.) These divide into branches, 
 and these again into leafets, differing in each 
 case in number, length, and volume generally. 
 
 The other slips or bundles that issue from the 
 ganglion proceed backwards, upwards, down- 
 wards, and outwards, and expand into layers, 
 which are disposed horizontally. Those that 
 come from the middle of the ganglion are the 
 
124 
 
 longest, the others are successively shorter as 
 they issue nearer to the commencement of the 
 ganglion. (PL viii. fig. 1, pi. ix. 1 and 2, and pi. 
 xi. fig. 1, B.) 
 
 The peripheral extremities of the bundles 
 thus disposed in lamellae, are, as well as when 
 they expand and form an uninterruptedly smooth 
 surface, covered with a layer of cineritious sub- 
 stance. 
 
 By a section carried vertically through the 
 middle of the ganglion in the direction of its 
 bundles, eleven principal trunks or branches are 
 commonly exposed. The nearer the cut runs to 
 the middle, or posterior edges, of the cerebellar 
 hemispheres, the greater will be the number of 
 branches discovered, as their quantity will be 
 fewer in proportion as it passes nearer to the 
 mesial line of the body. Two branches may fre- 
 quently be seen intimately united near the base 
 of the ganglion (pi. ix. fig. 2, and pi. xi. fig. 1. 
 B.), and forming, for some little way, a common 
 stalk ; but in other cases they proceed quite dis- 
 tinctly from the very beginning. Still greater 
 varieties are to be detected in the interior 
 divisions and subdivisions, which are unimpor- 
 tant, and require no particular mention. 
 
 The ganglion of the cerebellum varies con- 
 siderably in form, and this, not only in diffe- 
 rent species, but even in different individuals 
 of the same kind of animals. Its appearance 
 
125 
 
 also changes according to the mode in which it is 
 cut ; horizontally incised, it has the figure ex- 
 pressed in pi. viii. fig. 2, B. s . ; obliquely, the form 
 represented in pi. xi. fig. 1, B. s . ; and, verti- 
 cally, the contour given in pi. viii. fig. 1, and 
 pi. ix. fig. 1 and 2 s. A horizontal cut shews 
 it in its greatest extent. 
 
 Although the portions or ramifications of the 
 cerebellum be divided into parallel lamellae, they 
 do not ultimately lie parallel to each other ; each 
 portion thus considered is placed obliquely. 
 Neither are the furrows on the outer surface pa- 
 rallel. (PI. vi. fig. 1 and 2. PI. viii. fig. 1, B.) 
 Scemmerring has remarked, and exposed the 
 error generally committed by anatomists in this 
 matter in their drawings. It is also a mistake to 
 suppose, that the furrows of the cerebellum pe- 
 netrate deeply into its substance. They only do 
 so in the clefts that mark its principal divisions. 
 
 In the mammiferous class of animals the cere- 
 bellum is augmented by the addition of a mass, 
 known variously by the names pons Yarolii, 
 tuber annulare, or mesolobe. The transverse 
 fibres of this part evidently belong to the hemi- 
 spheres or lateral portions of the cerebellum, to 
 Which they bear a marked and regular propor- 
 tion. (PI. viii. fig. 2.) No one can deny to Dr. 
 Gall and me the merit of having first detected 
 the relations that exist between the annular pro- 
 tuberance and cerebellar hemispheres. M. Tiede- 
 
126 
 
 mann * says, that we err in deriving the trans- 
 verse fibres of the annular protuberance from 
 the cineritious substance covering the leafets of 
 the cerebellum, because these transverse fibres 
 are visible before any division into lamellae can 
 be recognised in the cerebellum. This reasoning 
 of M. Tiedemann, however, does not seem very 
 conclusive, since the annular protuberance and 
 cerebellum are developed at the same time. It is, 
 on the other hand, at least certain, that M. Tie- 
 demann is himself mistaken, in supposing the 
 transverse fibres of the annular protuberance to 
 come in part from the corpus dentatum (gan- 
 glion of the cerebellum.) f The annular protu- 
 berance lies most evidently anteriorly and quite 
 externally to the ganglion of the cerebellum ; its 
 fibres, moreover, may easily be demonstrated, as 
 commencing directly from the lamellas of the 
 hemispheres. (PI. viii. fig. 2.) 
 
 I, for my part, insist rather on the progressive 
 augmentation of the cerebellum in the different 
 classes of animals, than on the successive in- 
 crease of its individual constituent parts. It ap- 
 pears certain, that the several parts of the ce- 
 rebellum are not simultaneously developed ; that 
 some of these are visible at an earlier period than 
 others, But it still remains a point of great dif- 
 
 * Anatomie du Cei’veau dans le Foetus Humain, Nurnberg, 
 1816. 
 
 t Op. cit. p. 107. 
 
127 
 
 ficulty to determine the part which serves as the 
 centre of departure or originator of the others. 
 Are the various portions developed after the man- 
 ner of the graft of a fruit-tree, or are there 
 branches thrown off in succession, or, are the rudi- 
 ments of the whole called into a being at once, 
 and maturity of growth then acquired by each in 
 succession ? The first supposition, I confess, ap- 
 pears the most probable to myself. It is not 
 unreasonable also to presume, that the fibres 
 of communication, and the fibres of the commis- 
 sures, or apparatuses of union, appear together, 
 whilst the peculiar apparatus which is to perform 
 a special function, acquires the form, volume, 
 and organic condition necessary to this duty by 
 degrees. 
 
 Although the cerebellum be ever more com- 
 plicated as we ascend in the scale of beings, it 
 is a fact, that animals do not exhibit faculties in 
 proportion as this mass presents a larger number 
 of lamellae or ramifications. Neither is it found 
 that the intellectual and other general mental 
 powers of individuals of the human kind in- 
 crease, or are active in the ratio of the cere- 
 bellar lamellae, as was once maintained by Mala- 
 carne. 
 
 Many authors have said, that the cerebellum 
 contained, in proportion to its bulk, more cine- 
 ritious substance than the brain, and as a conse- 
 quence of this notion, it came to be regarded as 
 
128 
 
 softer than the brain. Both of these assumptions 
 are incorrect. The primary mistake was pro- 
 bably committed from vertical sections having 
 always been employed to expose the internal 
 structure, i. e., the arbor vitae of the cerebellum, 
 whilst horizontal slicing was the method fol- 
 lowed in regard to the brain. But let an opposite 
 procedure be adopted ; let the cerebellum be 
 trenched horizontally, and the brain vertically, 
 and, for certain, more cineritious substance will 
 then appear in the brain than in the cerebellum. 
 The cerebral convolutions again, it is natural to 
 think, will, on account of their mere thickness, 
 seem firmer than the cerebellar leafets ; but care- 
 ful examination proves that in one case the 
 brain, and in another the cerebellum, possesses 
 the greatest degree of consistency. Age and for- 
 tuitous circumstances, as disease, &c., exert a 
 particular influence in this respect. 
 
 From what has been said when discussing the 
 nerves of the external senses and voluntary mo- 
 tion, it may almost be unnecessary here to state, 
 that none of them arises from the cerebellum. 
 
 All the parts of the cerebellum are double, 
 or exist in pairs ; its primary portion or vermiform 
 process, is no exception to the law ; all its parts, 
 however, are not necessarily symmetrical ; the 
 elements composing each side are alike, but the 
 size of the essential bundles, the length and 
 thickness of their branches, the number of sub- 
 
129 
 
 divisions of these, and the form and lie of the 
 lamellae vary extremely in different individuals, 
 and often on both sides of the same cerebellum, 
 the entire mass of one side being not unfrequently 
 more largely developed than that of the other. 
 
 In their descriptions of the cerebellum, anato- 
 mists still make mention of two soft and thin 
 layers, the one of which unites the upper part 
 of the posterior pyramidal bodies with the lower 
 portion of the vermiform process (the primary 
 or essential mass), whilst the other brings the 
 cerebellum into connexion with the quadrigemi- 
 nal tubercles. The latter is commonly known by 
 the name of the valve of Yieussens, or by the 
 singular title of processus u cerebello ad testes. (PI. 
 xi. fig. 1 and 3. y.) Reil styles them the supe- 
 rior and inferior medullary veils. 
 
 The valve of Vieussens, or layer of commu- 
 nication between the primary portion of the ce- 
 bellum and quadrigeminal tubercles, may be dis- 
 tinctly traced through all the four classes of ver- 
 tebral animals. It increases in size in the ratio 
 of the distance and nervous masses, between the 
 cerebellum and quadrigeminal tubercles. The 
 inferior veil, on the contrary, is but just apparent 
 in birds ; in the mammalia, however, like the 
 superior, it is conspicuous, although varying in 
 size in the different species composing the class. 
 
 The idea of a determinate proportion between 
 the brain and cerebellum is one still very gene- 
 
 K 
 
130 
 
 rally entertained. Authors on the comparative 
 anatomy of the brain have even drawn up tables 
 of this supposed proportion. “ It is easy,” says 
 M. Cuvier *, “ to ascertain the proportionate 
 weight of the brain and cerebellum, because no 
 variation in health, and no change in the bodily 
 condition, as to obesity or leanness, exert any 
 influence on them.” But it is long since Dr. Gall 
 and I shewed, that the cerebellum has no re- 
 gular proportion to the brain. In the adult a 
 small cerebellum is often met conjoined with a 
 very large brain, and in other cases the cerebel- 
 lum occurs of great size, while the brain is par- 
 ticularly small. M. Chaussier has also observed, 
 that the cerebellum composed at one time the 
 sixth, at another the seventh, and at another, 
 and more rarely, the tenth of the weight of the 
 encephalon. In newly-born infants, he found 
 that it was the thirteenth, the fourteenth, the se- 
 venteenth, and, in one instance, no more than 
 the thirtieth part, by weight, of the encephalon. 
 Whoever, indeed, will be at the pains to com- 
 pare the encephalon of children of two, four, six, 
 and ten, and of young people up to their six- 
 teenth year, will be convinced, that relatively 
 to the brain the cerebellum is at these periods 
 smaller than in adult age. If any exception to 
 the rule be found, it must be regarded as an in- 
 dividual peculiarity of organization. Moreover, 
 * Lean’s d’Anatomie Compaiee, vol. ii. p. 152. 
 
131 
 
 the cerebellum is generally larger in men than in 
 women, and in males than in females of the same 
 kind of animal. 
 
 Let us now examine some points of M. Series’s 
 Prize Memoir, in relation to the cerebellum. 
 
 He says*, “ it may appear singular, that the 
 cerebellum should not be formed till after the 
 quadrigeminal tubercles ; nevertheless, there is 
 no exception to this fact in any class.” 
 
 Now this fact will not appear singular, but seem 
 perfectly natural to those who are acquainted 
 with the functions of the apparatus that arises 
 from the quadrigeminal bodies, and with the 
 office of the cerebellum. As the optic nerve has 
 to act long before the cerebellum, its organiza- 
 tion requires to be complete long before that of 
 the cerebellum needs to be perfect. Further, the 
 brain is also developed at a later period than the 
 quadrigeminal bodies, the cerebellum conse- 
 quently presents nothing whatever that is singu- 
 lar in this respect. 
 
 “ The vermiform process,” says M. Serres in 
 another place f, “ comes from the quadrigeminal 
 tubercles, whilst the other part, issuing from the 
 restiform bodies, constitutes the hemispheres of 
 the cerebellum. The two elements of the cere- 
 bellum, (the vermiform process and lateral parts,) 
 also, though united, are still entirely independent 
 of each other.” 
 
 t Ibid. p. 68. 
 
 K 2 
 
 * Rapport de Hnstitut, 1820, p. 68. 
 
132 
 
 These propositions do not to me seem founded 
 in nature. Were we to admit the bigeminal bo- 
 dies of fishes and reptiles, and the quadrigemi- 
 nal tubercles of the mammalia, as the source of 
 the vermiform process, or primary portion of the 
 cerebellum, we should then expect some regular 
 proportion in the development of these parts to 
 each other. But M. Serres himself excepts rep- 
 tiles. “ In all the classes except that of rep- 
 tiles,” he says *, “ the median lobe of the cere- 
 bellum ( processus v er mien lair e superieur,) is deve- 
 loped in the direct ratio of the quadrigeminal 
 bodies.” Now this exception is of itself suffi- 
 cient to refute M. Serres’s entire assumption. 
 However, let the cerebellum be compared with 
 the optic tubercles in the sturgeon, in the eel 
 (pi. ii. fig. 1), flounder (pi. ii. fig. 4), skate (pi. 
 ii. fig. 3), barbel (pi. ii. fig. 12), pigeon, turkey, 
 dog, and other animals, to procure data, by 
 which to estimate the utter erroneousness of 
 M. Serres’s opinions. On dissecting the cerebel- 
 lum of mammiferous animals, the vermiform pro- 
 cess, as well as the other ramifications, generally, 
 will be seen communicating distinctly with the 
 defltated body, or ganglion of this organ. Lastly, 
 and still further, to expose this error relative to the 
 origin of the primary portion of the cerebellum, let 
 us recur to pathological anatomy, as well to the 
 cases produced accidentally or by disease, as to 
 
 * Rapport de l’lnstitut, 1820. p. 68. 
 
133 
 
 those created intentionally, or by mutilations 
 Atrophy of the optic nerves, caused in any way. 
 is well known to extend to the anterior pair of 
 quadrigeminal bodies ; no one, however, has yet 
 imagined that it was continued on to the median 
 lobe, or primary portion of the cerebellum. The 
 optic tubercles and the vermiform process, there- 
 fore, exist independently of each other ; they 
 are connected, only that they may exert a mutual 
 influence. 
 
 It is not the same in regard to the median lobe 
 and the lateral parts of the cerebellum. True it 
 is, that these two masses are not necessarily pro- 
 portionate to each other ; this fact, however, does 
 not prove each entirely independent of the other, 
 as M. Serres has presumed *. I take his own man- 
 ner of viewing the matter in illustration : he re- 
 gards the bigeminal tubercles of birds, reptiles, and 
 fishes, and the quadrigeminal bodies of the mam- 
 malia and man, as essentially analogous masses ; 
 the quadrigeminal appearance in mammiferous 
 tribes, he conceives to arise from a transverse 
 furrow, which, in the human kind, commonly 
 passes across the middle of the mass, which, in 
 the carnivora, runs more anteriorly, and in the 
 ruminantia and rodentia, passes more posteriorly, 
 and thus makes the two pairs of tubercles ap- 
 pear of nearly equal size, or causes the front or 
 back pair to predominate f. The two pairs of 
 * Rapport, &c. p. 66. t Ibid. p. 68. 
 
134 . 
 
 tubercles, therefore, vary in proportionate size in 
 the different tribes of mammiferous animals, pre- 
 cisely as do the median and lateral lobes of the 
 cerebellum. Now if, according to M. Serres, the 
 dissimilar development of the different pairs of 
 the quadrigeminal bodies does not prove their 
 independence, I do not see that it is reasonable 
 to regard diversity of development of the median 
 and lateral lobes of the cerebellum as any proof 
 of their independence. 
 
 M. Serres thinks that the spinal cord, the me- 
 dian lobe of the cerebellum, and the quadrigemi- 
 nal tubercles are developed in the direct ratio of 
 each other, and in the inverse ratio of the cere- 
 bellar hemispheres and annular protuberance. 
 
 I have said that M. Serres himself excepts the 
 class of reptiles from this law. and I have added 
 other facts which refute his opinion regarding 
 the dependence of the median cerebellar lobe on 
 the quadrigeminal bodies. I have also shewn 
 above, that the direct ratio of development which 
 M. Serres recognises between the spinal cord 
 and the quadrigeminal tubercles has no founda- 
 tion in nature. An appeal to the same authority 
 also proves that M. Serres deceives himself, when 
 he fancies the spinal cord, the median cerebellar 
 lobe, and the quadrigeminal tubercles to be 
 developed inversely as the lateral parts of the 
 cerebellum and annular protuberance. For in 
 lishes, reptiles, and birds, there are no cerebellar 
 
135 
 
 hemispheres, and no annular protuberance. The 
 lateral parts of the cerebellum and annular pro- 
 tuberance are, in fact, developed in a greater or 
 less degree in different tribes, but never inversely 
 as the optic tubercles and spinal cord are con- 
 cerned. The flounder (pi. ii. fig. 7), and carp 
 (pi. ii. fig. 5), have optic tubercles of greater size 
 than the eel (pi. ii. fig. 1), which of the three 
 kinds, however, has the most voluminous spinal 
 cord. 
 
 M. Serres also notices several relations between 
 the annular protuberance and different other ce- 
 rebral parts. Dr. Gall and I were the first who 
 shewed the development of the annular protu- 
 berance in the direct ratio of the cerebellar hemi- 
 spheres. No other one of the relations, mentioned 
 by M. Serres, is constant; and, consequently, no 
 other can be laid down as a law. The annular 
 protuberance, for instance, is not regularly de- 
 veloped in the inverse ratio of the cerebellar 
 median lobe, of the quadrigeminal tubercles, and 
 spinal cord, as M. Serres pretends *. The annular 
 protuberance, in general, is relatively less con- 
 siderable in women than in men, but the spinal 
 cord is not developed in an inverse ratio in the 
 two sexes. I shall expose another of M. Serres’s 
 errors, in supposing the annular protuberance to 
 bear a directly proportionate development to the 
 
 * Rapport, &c., p. 69. 
 
136 
 
 corpus callosumf , when I come to speak of the 
 last-named cerebral mass. 
 
 The advantage, it seems to me, would be little 
 commensurate with the labour of ascertaining 
 all the modifications presented by the cere- 
 bella of different animals, and of giving titles to 
 every lobule superadded to the primary or median 
 portion. Such inquiries appear to me the rather 
 superfluous, as I view the entire cerebellum in the 
 light of a single organ or apparatus, and as per- 
 forming only one species of function. 
 
 I have still to add, that the cerebellum, like 
 every other organ, is not only more or less com- 
 plex in the different kinds of animals, but also 
 that its several constituent parts are modified in 
 the various individuals of the same species. The 
 organ too, I may here observe, is developed 
 at rather a late period of life, a fact which I have 
 already had occasion to cite, in shewing that there 
 was no regularity of proportion between the brain 
 and cerebellum ; I, however, call my readers’ at- 
 tention to the phenomenon, at present, in order 
 that he may understand the tardy appearance 
 of the function of the part (the sexual appetite). 
 For the sake of physiology, I also adduce in this 
 place, the fact of the larger size, generally, of the 
 cerebellum in men and males, than in women and 
 females of the several kinds. 
 
 * Rapport, &c., p. 72. 
 
137 
 
 The cerebellum, then, is an apparatus of a 
 structure, more or less complicated in different 
 species of animals, having a greater or smaller 
 development in the two sexes, and in different 
 individuals of the same kind, and being in direct 
 communication with the medulla oblongata and 
 quadrigeminal tubercles. 
 
 To obtain as clear and comprehensive ideas of 
 the position and external and internal structure 
 of the cerebellum, as possible, I request my 
 reader to turn to, and peruse the plates in the 
 order as follows : — 
 
 For differences of form, of volume, and of su- 
 perficial structure, see pi. ii. figs. 1, 2, 5, 7, 10, 
 11, 12; pi. iii. figs. 2, 3, 4, 5, 7, 10, and 11 ; pi. iv. 
 figs. I, 3, 5, and 6; pi. v. figs. 3, 4, 5, and 6; pi. vi. 
 figs. 1 and 2. For the appearances and connec- 
 tions in the median line, examine pi. viii, fig. 2. 
 
 In oviparous animals, the cerebellum is hollow, 
 as is seen in pi. xi. fig. 3, 62. In the mammalia 
 and man it is solid ; in them, there is nothing that 
 can be likened to a cavity, except the separation 
 between its primary portion and the medulla ob- 
 longata, or rather the posterior part of the annu- 
 lar protuberance ; see pi. vii. fig. 2, m; and pi. xi. 
 fig. 1, m. 
 
 The disposition of the cerebellar ramifications, 
 from birds up to man, is lamellar, as it is presented 
 in pi. iii, fig. 1; pi. viii. fig. 1 and 2; pi. ix. fig. 
 1 and 2; and pi. xi. figs. 1, 3. 
 
138 
 
 For the appearance and structure of the cere- 
 bellar commissure (annular protuberance,) in- 
 spect pi. iv. fig. 2; pi. v. figs. 3 and 5; pi. vi. 
 fig. 11, 2; and pi. viii. figs. 1 and 2. 
 
 The ganglion of the cerebellum (dentated body) 
 is represented in pi. viii. figs. 1,2; and pi. xi. 
 fig. 1, B. s. 
 
 To demonstrate the connexion of the cerebel- 
 lum with a bundle of the restiform body, the me- 
 dulla oblongata must be pushed to one side, and 
 the auditory nerve and a thin layer interposed 
 between the medulla and the cerebellum, scraped 
 off with the handle of the scalpel. The second 
 bundle of the restiform body, reckoning from the 
 posterior pyramid, will then be seen to plunge 
 into the cerebellum. By entering the point of the 
 knife at the insertion of this bundle, and cutting 
 the cerebellum vertically, so that about two thirds 
 of its substance may be left externally, and the 
 other third remain internally, the communication 
 of the cerebellum with the medulla oblongata; its 
 ganglion, from the entrance of the connecting 
 bundle of the restiform body to about its middle ; 
 the ramifications of the white substance; and the 
 peripheral extremities of the various branches 
 universally covered with cineritious matter, con- 
 stituting the appearance denominated arbor vitee, 
 will all be exposed. These peculiarities are repre- 
 sented in pi. viii. fig. 1. 
 
 To see that the uniting fibres of the cerebellum, 
 
139 
 
 composing the annular protuberance or commis- 
 sure, are distinct from those of the bundle that 
 connects it with the medulla oblongata, the last- 
 named part must be turned aside, and the vocal, 
 glosso-pharyngeal, facial, and auditory nerves re- 
 moved with the handle of the scalpel ; the fibres 
 of union will now be seen gathering themselves 
 from the peripheral parts, and lying over the 
 bundle that springs from the medulla oblongata, 
 and plunges into the cerebellar ganglion. Finally, 
 every cut in the direction of the cerebellar 
 lamellae exhibits a white surface, as is pictured in 
 pi. viii. fig. 2. 
 
HO 
 
 SECTION VI. 
 
 Of the Brain. 
 
 In the preceding section, I have shewn anatomy, 
 physiology, and pathology, concurring to prove 
 the cerebellum a single and peculiar instrument. 
 In this respect, it is the opposite of the mass pro- 
 perly styled brain. I have, already, exposed the 
 anatomical proofs of the brain’s complexness, 
 and for the evidence which physiology and pa- 
 thology afford, referred my reader to the respec- 
 tive treatises upon these subjects*. 
 
 Conviction of the brain, properly so called, 
 being an assemblage of instruments, is readily 
 obtained ; but to specify the limits of these instru- 
 ments, individually, in the different species of 
 animals, is a matter of extreme difficulty, if it be 
 not, perhaps, impossible. 
 
 Let us follow the procedure of nature in this 
 part of our inquiry, and, commencing with the 
 most simple brains, pursue them in their increas- 
 ing complexness as we mount in the scale of 
 beings, until we arrive at that of man, the most 
 complicated of all. They who have gone into 
 the comparative anatomy of the nervous masses, 
 
 * Phrenology or the Doctriue of the Mind; Lond. 1825, 
 and Observations on Insanity ; Lond. 1816. 
 
141 
 
 have constantly assumed the human brain as their 
 type of comparison. This they have always viewed 
 as a simple mass; and then, the hemispheres, 
 the three lobes, the callous body, the anterior, 
 middle and posterior commissures, the infundibu- 
 lum, the mammillary bodies, the fornix, the sep- 
 tum lucid um, the hyppocampus’s foot, the streaked 
 bodies, the optic thalami, the semicircular tsenia, 
 the quadrigeminal tubercles, the aqueduct of 
 Sylvius, the valve of Vieussens, the peduncles of 
 the brain, the annular protuberance, the medulla 
 oblongata with its pyramidal, olivary, and resti- 
 form eminences, and lastly, the ventricles and 
 their communications, have been their grand ob- 
 jects of comparison. The existence of parts, as 
 this specimen of the nomenclature, in use, suffi- 
 ciently proves, appears, therefore, to be admitted, 
 or denied according to mere physical indications, 
 the form and situation of the masses being es- 
 pecial guides to the conclusions formed. 
 
 But this mode of studying the comparative 
 anatomy of the brain, is insufficient. In the first 
 place, it is certain that the mass, styled brain, 
 consists of a multiplicity of instruments perform- 
 ing particular functions ; again, it is undeniable 
 that the cerebral parts, as they are spoken of, in 
 systems of descriptive anatomy, do not constitute 
 entire and special organs ; that several of them, 
 indeed, occasionally, go to compose a single ap- 
 paratus, a circumstance which we have observed 
 
142 
 
 in reference to the cerebellum, when treating of 
 that part. Further, it is no less obvious that the 
 identity of the individual organs in the various 
 classes of animals, ought to be determined by 
 means of physiology, seeing that the forms of 
 those which are known to be analogous often vary 
 immensely. I have already said,that no anatomist, 
 Avho, in ignorance of the sense of smell, should 
 examine the mere configuration of the encephalic 
 masses, would venture to maintain that the olfac- 
 tory nerves of the skate, flounder, fowl, seal, and 
 ox, were masses performing analogous functions. 
 And the outward appearances of the other cere- 
 bral instruments are not less diversified than are 
 those of the organ of smell. It is, consequently, 
 in vain attempting to advance the comparative 
 anatomy of the brain, without a knowledge of the 
 affective and intellectual faculties of animals, and 
 of the functions performed by the different cere- 
 bral organs. 
 
 The brain being made up of very many parts, 
 whose functions are entirely dissimilar, the con- 
 nexion of these with the nervous masses of vo- 
 luntary motion, and of the five external senses, 
 with the spinal cord in particular, requires to be 
 examined. The cerebral organs have several 
 primary roots, or bundles in the medulla ob- 
 longata ; these bundles have been particularized 
 by the names anterior and posterior pyramidal, 
 and olivarv, and restiform bodies. From what has 
 
143 
 
 been already said, however, it is evident that 
 the last-mentioned masses do not belong exclu- 
 sively to the brain ; we have seen that they in- 
 clude the roots of several nerves, and the pri- 
 mary bundles of the cerebellum. In the human 
 kind all the three portions of the medulla ob- 
 longata are very distinct ; but they severally be- 
 come less and less evident as we descend in the 
 scale of beings, and when we arrive at fishes 
 we are almost tempted to doubt their existence 
 altogether. Some, indeed, go so far as to deny 
 these animals a brain. To me, however, it ap- 
 pears that every vertebral animal has a brain in 
 the strict and proper sense of the word ; all have 
 a nervous mass superadded to the nerves of 
 the external senses and voluntary motion; and 
 fishes, which besides a cerebellum, seem to 
 have ganglions of nerves of sense only, may be 
 proved to possess a true brain in addition. The 
 proof lies in this, that ganglions in general are 
 proportionate to the nerves arising from them ; 
 but the ganglions of the skate, and the three 
 pairs of ganglions which, in the eel, are regarded 
 as the origins of the olfactory nerves, and the 
 optic ganglions of the carp, pike, and many others 
 of the class, are much too large in proportion 
 to the nerves which issue from them. I, there- 
 fore, contend, that the olfactory and optic 
 nerves of fishes communicate with certain cere- 
 bral parts, destined to peculiar functions, pre- 
 
cisely as the same nerves do in birds and the 
 mammalia, with this difference only, that 
 the masses they communicate with are of dif- 
 ferent sizes in these different species of animals. I 
 repeat then, that with M. Arsacky », I conceive 
 the complex structure of the optic ganglions in 
 fishes to explain the functions which in reptiles, 
 birds, and mammiferous animals, are obviously 
 performed by certain parts with which the optic 
 nerves communicate. I apply the same idea to 
 the ganglions of the olfactory nerves. In the 
 eel, for example, I only give the anterior pair to 
 these nerves ; and in the skate, no more than 
 the outer parts of the ganglions with which they 
 communicate. 
 
 M. Cams, in his work on the brain f, broaches 
 an idea that deserves a passing notice ; it is to 
 determine whether, when the cerebral parts are 
 separated from each other at their peripheral ex- 
 tremities, this is to be regarded as a sign of per- 
 fection or of imperfection. M. Cams himself con- 
 siders the brain to be perfect in proportion as its 
 masses approach unity. The brain of the eel is, 
 according to him, extremely imperfect, on ac- 
 count of the separation of its constituent parts. 
 
 This opinion seems to me too general, and 
 but little satisfactory. We know that the brain 
 
 * Dissertatio de Piseium Cerebro et Medulla Spinali, Halse, 
 1813. 
 
 t Carus, Darstellung des Gehims, Leipzig, 1814. 
 
145 
 
 and the cerebellum are always separate from 
 each other. In proportion too as the last is per- 
 fected in the four classes of vertebral animals, 
 its different parts become more numerous, more 
 distinct, and lie farther from each other, espe- 
 cially towards their peripheral extremities. The 
 brains of reptiles, of birds, and of several mammi- 
 ferous animals, consist of two smooth hemispheres ; 
 in proportion, however, as the brain in superior 
 classes of beings has more numerous offices to 
 perform, that is, as it increases in perfection, 
 the division into lobes becomes distinct, and con- 
 volutions appear. The cerebral hemispheres of 
 the human foetus are at first smooth, but as the 
 encephalon is developed, the separation of its 
 peripheral parts grows ever more conspicuous. 
 
 I divide the functions of the brain into two 
 classes: viz., affective and intellectual; and, in 
 harmony with this physiological division, I re- 
 cognise two kinds of cerebral parts. The ante- 
 rior pyramidal bodies I consider the rudiments of 
 such as belong to the intellectual operations ; and 
 the other bundles of the medulla oblongata (in 
 man they consist of the olivary and part of the 
 restiform bodies) which run across the annular 
 protuberance to communicate with many of the 
 cerebral masses, as the roots of those that pertain 
 to the affective manifestations. 
 
 This separation into two systems of parts is 
 
 L 
 
146 
 
 very evident from the medulla oblongata up- 
 wards, as far as the pretended optic thalami and 
 striated bodies in man and the mammalia. Let us 
 then examine them one after another through 
 their entire course, commencing with the bundles 
 of the intellectual faculties. 
 
 The pyramidal bodies are scarcely to be de- 
 monstrated in birds, and still less are they to be 
 seen in reptiles and fishes ; in the lowest mam- 
 miferous tribes, however, they are abundantly 
 evident. They differ in general size and length, 
 not only in the various species of animals, but 
 also in individuals of the same, especially of the 
 human kind. In man they usually commence 
 about twelve or fifteen lines below the annular 
 protuberance. As they approach this mass, they 
 increase gradually in size, and it is in consequence 
 of this structure that they have obtained their 
 name. 
 
 There is a striking peculiarity in the mode 
 of origin of these bundles : the primary fibres 
 of each do not issue from the same side as that 
 on which they lie, but uniting, in the first in- 
 stance, into two, three, or as many as five little 
 cords, they cross the mesial line of the body, 
 one above another, from below upwards ; the 
 bundles of the right pyramidal body, there- 
 fore, come from the left side, and those of the 
 left pyramidal body from the right side of the 
 
147 
 
 spinal cord. The structure just described is 
 termed the decussation of the pyramidal bodies. 
 It is a constant peculiarity, but it is modified as 
 the number of decussating cords is concerned. 
 When they are numerous, the appearance that 
 results very much resembles plaited straw. In 
 some very rare instances the two pyramidal bo- 
 dies cross, as entire and undivided masses, from 
 one side to the other. 
 
 The decussation of the pyramidal bodies is a 
 point of much importance in a physiological 
 and pathological point of view. It is very long 
 since cases of disease impressed the idea of a 
 nervous decussation on the minds of medical 
 men. Lesions on one side of the head were 
 often observed to occasion so unfortunate a 
 symptom as palsy on the opposite side of the 
 body. Hippocrates himself mentions the cir- 
 cumstance, but Aretffius was the first who at- 
 tempted to explain it, by supposing a decussa- 
 tion of the nerves at their origin in the brain. 
 Dion Cassius is the next who speaks of a decus- 
 sation of the cerebral nerves and spinal cord, but 
 with him the subject dropt, and the attention of 
 the medical world was only recalled to the fact 
 in 1581, by Fabricius Hildanus. The true de- 
 cussation of the pyramidal bodies, however, was 
 first described by Mistichelli, in 1709 ; it was 
 noticed by Petit in the year following, and at 
 later periods by Lieutaud, Santorini, and Win- 
 
 L 2 
 
148 
 
 slow. The same authors also speak of other de- 
 cussations, but probably on mere supposition. 
 
 Modern anatomists, before Dr. Gall and my- 
 self, were divided in opinion upon the subject of 
 decussation. Many admitted the fact, but no one 
 pointed put the place of its existence. Yicq 
 d’Azyr, for example, confounds the simple trans- 
 verse fibres between the two halves of the spi- 
 nal cord with the true decussation of the pyra- 
 midal bodies. Many others, among the number 
 Prochaska, Barthez, Sabatier, Boyer, Dumas, 
 Bichat, and Chaussier, have, in the most positive 
 terms, denied the decussation of the pyramidal 
 bundles altogether, as we have shewn in our 
 reply to the report of the Committee of the 
 French Institute upon our Anatomical Memoir. 
 
 To demonstrate the decussation of the pyra- 
 midal bundles, we do not require any such mace- 
 ration as Santorini believed necessary. It is 
 sufficient to strip off the pia mater to shew the 
 structure. Let a slight cut be made through the 
 membrane in the median line, without implicating 
 the cords beneath, the edges then separated 
 gently, and the decussation will appear. It will 
 now be easy to reckon the number of bundles, 
 and to take them away in succession with the 
 handle of the scalpel. (PI. viii. fig. 1 — 1.) 
 
 The decussation at this place is incontestable ; 
 but whether there be any similar peculiarity in 
 other situations, and whether that of the pyra- 
 
149 
 
 mi dal bodies suffices to explain all pathological 
 phenomena, are points that still remain undeter- 
 mined. 
 
 Some authors believe that the bad symptoms 
 which attend lesions of the encephalon are al- 
 ways manifested on the side of the body oppo- 
 site to that on which the injury occurs. Others 
 again cite cases where injuries of one cerebral 
 hemisphere have caused pathological symptoms 
 on the same side of the body. “ Although the 
 palsy of the body,” says Haller*, “produced 
 by injury done to the brain, be commonly mani- 
 fested on the opposite side, it often enough hap- 
 pens, that derangements of the brain and cere- 
 bellum affect the same side (as that on which they 
 happen).” He quotes De Haen, Schlichting, Mor- 
 gagni, and others, in illustration of the fact. 
 Prochaska believed that when the opposite side 
 of the body suffers from cerebral affections, it is 
 principally when the striated bodies are the seats 
 of disease. 
 
 Anatomy has as yet demonstrated no other de- 
 cussation in the medulla oblongata than that of 
 the pyramidal bundles. No crossing of fibres 
 has ever been found of the primary bundles of 
 the cerebellum, nor of the posterior cerebral 
 lobes, although physiological experiments and 
 pathological facts tend alike to prove that the in- 
 fluence of the cerebellar hemispheres is propa- 
 * Physiologia, t. iv. p. 333. 
 
150 
 
 gated to the opposite side of the body. May not 
 the cerebellum possibly act only through the me- 
 dium of the brain ? To such an hypothesis the 
 inability to perceive any proper lesion of the 
 brain cannot be well opposed as an objection ; 
 because it is not at all times possible to deter- 
 mine precisely whether the cerebral fibres are 
 healthy or diseased. The lesions may be per- 
 ceptible in one and not in another part. I con- 
 ceive that the cerebellum may be evidently dis- 
 ordered, and that the brain may suffer, in conse- 
 quence, without our being able to detect any traces 
 of disease in its organization, whilst the opposite 
 side of the body exhibits pathological symptoms. 
 The connexions of the various parts, and the re- 
 sulting influence of each on the others recipro- 
 cally, render observations on these matters diffi- 
 cult, and the conclusions deduced more or less 
 suspicious. Farther researches on the decussa- 
 tion of the nervous parts, not immediately con- 
 nected with the masses of the anterior pyramidal 
 bundles, are still wanted. The optic nerves de- 
 cussate partially, and this is the cause why the 
 eye is frequently deranged on the same side as 
 that on which the brain is diseased. 
 
 Let us now follow the pyramidal bundles in 
 their course towards the annular protuberance ; 
 and first, let us remark the fibres which are de- 
 tached from the pyramidal, towards, and around 
 the olivary bodies, the media of communication. 
 
151 
 
 probably, between these different bundles of the 
 medulla oblongata. (PL viii. fig. 2, 64*.) May 
 not these connecting fibres explain the influence 
 of the lateral cerebral parts upon the opposite 
 sides of the body ? 
 
 The pyramidal bodies, just as they enter the 
 annular protuberance, are somewhat contracted in 
 their thickness (ib. c), but they are, by no means, 
 interrupted in their course. Immediately after 
 having plunged into that mass, they separate into 
 several bundles, and are mingled with cineritious 
 substance (ib. f). Here, many new fibres arise 
 and join the others; all advance, some of them 
 disposed in layers, and some intersecting the bun- 
 dles of the annular protuberance.’ The pyramidal 
 bodies are so much increased in their passage, 
 that on emerging from the annular protuberance, 
 they compose the anterior and outer two-third 
 parts of the cerebral crura or legs (ib. g). 
 
 To see the structure of the annular protube- 
 rance distinctly, that is to say, to see the trans- 
 verse uniting fibres of the cerebellar hemispheres, 
 the longitudinal fibres communicating with the 
 pyramidal bodies, and crura of the brain, and the 
 cineritious substanee intermingled with each, an 
 incision of about a line in depth must be made 
 across the transverse fibres ; if the cut be made 
 deeper than this, it must not be carried in a straight 
 line, but in the slightly-curved direction of the 
 longitudinal bundles ; the transverse must now 
 
152 
 
 be separated from the longitudinal layers with 
 the scalpel, by pushing those, on the outside, to- 
 wards the hemispheres of the cerebellum, and 
 those on the inside, towards the mesial line of 
 the annular protuberance. 
 
 By this means, the mode in which the longi- 
 tudinal, or bundles of the pyramidal bodies are 
 augmented in the annular protuberance, as it 
 were in a true ganglion, is made evident. (PI. vii. 
 fig. 2, 88, and pi. ix. fig. 2, /.) 
 
 If these longitudinal bundles only are to be 
 examined, it is sufficient, by pushing the handle 
 of the scalpel upwards from its inferior edge, to 
 remove the transverse layer of the annular pro- 
 tuberance that covers them. 
 
 Certain it is, therefore, that great errors are 
 committed when the two crura of the brain are 
 described as blended together, and the annular 
 protuberance is styled a compound of the me- 
 dullary or white substances of the brain and 
 cerebellum. 
 
 The great bundles called crura of the brain, 
 thus appear to be, in part at least, a continuation 
 of the pyramidal bodies increased in size and 
 in perfection. These crura, as they advance, also 
 contain cineritious matter in their interior, from 
 which, additional fibres are continually sent off 
 to join and strengthen those that have come from 
 below. 
 
 In mammiferous tribes, the cerebral crura are 
 
153 
 
 very evidently divided into two parts, viz., an 
 anterior and external, and a posterior and internal 
 mass. Two superficial furrows mark their limits 
 respectively. They bear no regular proportion 
 to each other. In the human kind, the anterior 
 and external portion composes, as I have already 
 said, two-thirds, at least, of the entire crura ; but 
 in the lower animals, the posterior is, by much, 
 the more considerable portion of the two. 
 
 Before advancing further in our examination 
 of the longitudinal bundles which we have fol- 
 lowed from the pyramidal bodies across the an- 
 nular protuberance, let us first consider the origin 
 and progress of the bundles that compose the 
 posterior and inner portion of the cerebral crura. 
 
 I have already had occasion to say that anato- 
 mists, besides the pyramidal, speak of the olivary 
 and restiform bodies of the medulla oblongata of 
 man. I have also shewn that the restiform bodies 
 contain the origins of the primary bundles of the 
 cerebellum, and of the vocal, glosso-pharyngeal, 
 facial, and trigeminal nerves. The remaining 
 fibres of these, and the fasciculi of the olivary 
 bodies, mount behind the ganglion of the pyra- 
 midal bundles in the annular protuberance, and 
 joining themselves with, aid the completion of 
 the cerebral crura. In this course, they gain 
 some increase in size, which, however, is incon- 
 siderable compared with that of the pyramidal 
 
154 . 
 
 bundles. (PI. vii. fig. 2, 87, 90, and pi. ix. fig. 2, 
 a 70, 70.) 
 
 The olivary bodies are, themselves, true gan- 
 glions, and present the general forms (pi. ix. fig. 2, 
 a,) and modifications observable in the ganglion 
 or dentated body of the cerebellum. (PI. ix, 
 fig. 2, s .) Their size varies greatly in different 
 individuals. The cineritious and white substances 
 are observed to be variously distributed through- 
 out them. The modified appearances of the in- 
 terior of the olivary bodies depend, as in other 
 cases, on the mode in which they are incised for 
 examination. 
 
 The second, or posterior and inner portion of 
 the cerebral crura, is intimately connected with 
 the quadrigeminal bodies. In the mammalia, it 
 is much more voluminous than the anterior mass ; 
 and as we descend in the scale of beings, its re- 
 lative proportion increases continually. 
 
 These two portions of the cerebral crura con- 
 tain, so to say, the roots or primary bundles of the 
 hemispheres of the brain, properly so called. 
 They, however, it is evident, must be immensely 
 increased in volume before they can form such a 
 mass as the brain. It is at the upper extremity 
 of the anterior portion, where the optic nerve 
 winds over, and is attached to it by a pulpy layer, 
 that is to say, at the outer part of the striated 
 bodies, that the great augmentation takes place. 
 
155 
 
 After this, the fibres advance of unequal lengths, 
 and expanding into layers covered on their pe- 
 ripheral extremities with cineritious substance, 
 ultimately form the inferior, anterior, and exter- 
 nal convolutions of the front and middle cerebral 
 lobes. 
 
 To shew that the lower and inner convolutions 
 of the middle lobe, are formed by the anterior 
 and outer crural bundles, the middle lobe must 
 be removed. This is easily effected, as it is sepa- 
 rated from the anterior lobe by the fissure of 
 Sylvius. Besides the depth and extent of the 
 Sylvian fissure by this means exposed, certain 
 short convolutions which do not reach the surface, 
 will also be brought into view. These convolu- 
 tions lie hidden between the middle lobe and 
 the superior cerebral parts. The bundles which 
 issue from under the optic nerve, will also now 
 be seen to belong to the middle lobe, and to 
 the anterior part of the posterior lobe. (PI. viii. 
 fig. 1, w, w.) 
 
 If the entire outer part of the striated bodies 
 be removed, the manner in which the convolu- 
 tions, situated along the middle region of the he- 
 mispheres, on a level with the temples, arise from 
 the bundles in continuation with the pyramidal 
 bodies, will be made apparent. (PI. ix. fig. 1.) 
 The pyramidal bodies, their ganglions in the 
 annular protuberance, the anterior and outer por- 
 tions of the cerebral crura, and the convolutions 
 
156 
 
 in which their bundles terminate, are always de- 
 veloped in the direct ratio of each other. 
 
 Let us now trace the posterior and inner bun- 
 dles of the cerebral crura to their termination. 1 
 These plunge into a thick, massy, and firm gan- 
 glion, flattened in the middle, and unequal above, 
 and posteriorly ; this is generally known under 
 the name of optic thalamus, it having been long 
 regarded as the origin of the visual nerve. The 
 error, here committed, I have exposed in speaking 
 of the apparatus of vision. 
 
 These ganglions, commonly called thalami, are 
 developed in the direct ratio of the cerebral con- 
 volutions dependent on them. The posterior and 
 inner portions of the cerebral crura being larger 
 in the lower animals than the anterior and outer 
 masses of the same, it follows that the convolu- 
 tions of the upper and posterior parts of the he- 
 mispheres, must be more considerable than those 
 of the anterior and middle lobes. The most in- 
 ternal part of the thalamus, is the largest in ani- 
 mals, consequently, so is the mass of convolutions 
 that belongs to it. 
 
 In the interior of the cerebral ganglion we are 
 now discussing (pi. ix. fig. 2, p), there are a great 
 number of very fine nervous filaments ; these unite 
 at its superior edge into bundles, which then 
 diverge towards the convolutions in the man- 
 ner of rays. 
 
 The two portions of the ascending masses, called 
 
157 
 
 cerebral crura, which I have just described, may 
 be separated from each other either by the blow- 
 pipe, or a stream of water. At the place, how- 
 ever, where they issue from the thalami to enter 
 the striated bodies, their fibres are all so inti- 
 mately united by a transverse tissue, that any 
 farther partition of the two portions becomes im- 
 possible. 
 
 The anterior bundles of the thalamus traverse 
 the striated bodies. These are so named, be- 
 cause, when cut in the usual mode, anatomists 
 fancied they beheld alternate streaks of white, 
 and of cineritious substance. But the gray mat- 
 ter is not disposed in bundles ; it is a mere mass 
 traversed by white diverging fibres. By scraping 
 away to about the middle, or to the place where 
 the large white bundles pass, the cineritious sub- 
 stance will be seen disposed in the form of streaks 
 between them ; a closer inspection, however, 
 proves that it only lies in the intervals between 
 the fibrous bundles. 
 
 The masses styled optic thalami and striated 
 bodies, therefore, are true ganglions, in which 
 the primary bundles of the brain are increased in 
 their progress to completion in the convolutions 
 of the brain ; for the radiated diverging fasciculi 
 expand into layers, and, being covered with cine- 
 ritious substance on their extremities, compose 
 the convolutions. 
 
 The faultiness of the ordinary method of ex- 
 
158 
 
 amining the structure of the brain will now be, 
 in some degree, appreciated. Instead of tracing 
 the masses from their rudimentary state upwards 
 to completion, anatomists have been in the habit 
 of commencing the dissection by mutilating the 
 parts when already arrived at perfection. 
 
 By scraping the parts, Vieussens followed, and 
 has given a rude drawing of the nervous bundles 
 in connexion with the pyramidal bodies. These 
 fasciculi, however, he derives from his oval centre; 
 he was altogether ignorant of their destination — 
 the formation of the convolutions. He conceived 
 them all to unite in the pyramidal bodies ; he, 
 therefore, had no idea of the successive addi- 
 tions to, or of the augmentations of, the primary 
 bundles. 
 
 Vicq d’ Azy r has attempted to imitate the prepara- 
 tion of Vieussens in his twenty-second and twenty- 
 third plates; but the mass of gray substance, and 
 the nervous bundles which traverse, and partly 
 arise from it lying obliquely, he could not possibly 
 succeed by his horizontal incisions. In the striated 
 bodies he only saw alternate streaks of white and 
 gray substance ; these he also regarded as coming 
 from above downwards, to pass united in a single 
 bundle across the annular protuberance. He 
 has, moreover, neglected several rudimentary 
 bundles entirely ; he regarded the streaks of the 
 superior as shorter thtan those of the interior 
 parts, in consequence of having cut them first. 
 
159 
 
 and he was quite ignorant of their prolongation 
 into the convolutions. He only makes them pro- 
 ceed forwards, overlooking their sideward and 
 backward directions altogether. Vicq d’Azyr, 
 therefore, has done nothing more than picture, 
 and that in a faulty manner too, mutilated pieces 
 of the encephalon. 
 
 I conceive it of importance further to remark, 
 that the nervous fasciculi are less numerous but 
 larger in the posterior and middle than in the 
 anterior region. In the latter they are very nu- 
 merous, but also very small. (Vol. ix. fig. 2, and 
 pi. x. fig. 1, A. P. P.) This anatomical fact cor- 
 responds with what we know of the physiology 
 of the brain, and explains wherefore the organs 
 situated in the forehead are more numerous but 
 smaller than those which lie in the occipital 
 region. 
 
 Let us now glance over the comparative ana- 
 tomy of the cerebral parts, the structure of which 
 we have examined particularly in man. 
 
 The anterior pyramidal bodies are generally 
 distinct in mammiferous tribes, but they are 
 comparatively smaller than in the human kind. 
 The lateral parts of the medulla oblongata are 
 not formed like the olivary and restiform bodies 
 with which they correspond in man ; their fibres, 
 however, are certainly prolonged beneath and 
 across the transverse uniting fibres of the cere- 
 bellum. At their exit from this mass, the ante- 
 
160 
 
 rior and external parts of the cerebral crura are 
 observed to be proportionately smaller than the 
 internal and posterior portions. The relative 
 size of the two portions of the crura, indeed, are 
 found to vary exceedingly in the different tribes 
 of the mammalia. The anterior and outer bun- 
 dles, or continuations of the pyramidal bodies, 
 extend under the optic nerves (which by their 
 external edges communicate with the cerebral 
 masses precisely as in man), and on the external 
 parts of the striated bodies gain an increase of 
 size in the direct ratio of the anterior convolu- 
 tions of the middle lobes, of the outer convolu- 
 tions of the front lobes, and of those around the 
 
 • 
 
 fissure of Sylvius. The description of this ex- 
 ternal portion of the striated bodies is entirely 
 omitted in the work of Tiedemann. The posterior 
 and internal parts of the cerebral crura are inti- 
 mately connected with the quadrigeminal bodies ; 
 they then plunge into the pretended optic tha- 
 lami, and join themselves to the striated bodies ; 
 their structure, in short, is analogous to that of 
 the same parts in man. 
 
 In birds and the inferior classes all traces of 
 pyramidal bodies, visible in the mammiferous 
 tribes, disappear, and all analogy, as regards form, 
 with the medulla oblongata of man is lost. The 
 medulla oblongata, however, of all vertebral ani- 
 mals is invariably augmented downwardly and 
 outwardly in proportion as nerves of greater or 
 
161 
 
 smaller size are detached, or as the rudimentary 
 bundles of the proper cerebral masses are thence 
 derived. The mere outward form, here as else- 
 where, is not the essential consideration. It is 
 quite certain that several parts of the medulla 
 oblongata proceed forwards, and pass under the 
 optic nerve ; and that in birds and reptiles there 
 lies a mass below the posterior cerebral lobes, 
 and on the inner side of the crura, which resem- 
 bles in every thing the supposed optic thalamus ; 
 and, finally, that in the two classes mentioned, 
 the advancing bundles encounter true striated 
 bodies. (PI. xi. fig. 2 and 3, l. /.) 
 
 The pretended optic thalami and striated bo- 
 dies, or the two principal ganglions of the cere- 
 bral hemispheres, consequently, exist in birds 
 and reptiles, precisely as they do in man and the 
 mammalia. M. Serres must therefore be mis- 
 taken when he denies striated bodies in the 
 brains of these animals *. 
 
 Dr. Gall and I were unquestionably the first 
 who distinguished the true optic ganglions from 
 the supposed optic thalami, which are masses 
 belonging to the brain, and who demonstrated 
 the relations between the two cerebral ganglions 
 and the hemispheres. 
 
 Among fishes, in fine, certain cerebral masses 
 in the form of ganglions, and covered externally 
 
 * Rapport, &c. p. 70. 
 
 M 
 
162 
 
 with cineritious substance, are always to be found. 
 When treating of the optic and olfactory nerves, 
 I proved that the entire encephalic mass could 
 not be destined to originate them. But it is a 
 difficult task to compare analogous cerebral parts 
 in different tribes and classes of animals. In 
 fishes the medulla oblongata is evidently con- 
 tinued forwards, and from it are detached, in 
 succession, the primary bundles of the cerebel- 
 lum, and of the cerebral nerves ; but M. Serres 
 promulgates an error when he says, that the ce- 
 rebral hemispheres of fishes are simple rounded 
 bulbs, lying before the quadrigeminal tubercles, 
 in which the crura expand. Two longitudinal 
 bands we can observe continued onwards to the 
 
 % 
 
 olfactory nerves, with which a larger or smaller 
 number of ganglions communicate ; but whilst 
 the functions of these shall remain undiscovered, 
 they can only be designated according to their 
 numerical order. (PI. ii. fig. 1 and 13 ; 1, 2, 3, 4.) 
 The anatomists also certainly err, who speak of the 
 restiform bodies as simple bundles. The olivary 
 bodies, as they are not to be demonstrated in the 
 greater number of animals, cannot belong to the 
 quadrigeminal tubercles, as M. Tiedemann sup- 
 poses. 
 
 In reptiles, birds and the mammalia, the pro- 
 longation of the two great cerebral ganglions 
 compose the hemispheres, as they are styled, of 
 the brain. The volume of these varies extremely 
 
 a) 
 
163 
 
 in different kinds, and even in different indivi- 
 duals of the same species of animals, and this not 
 only in their totality, but also as their various 
 portions are concerned. 
 
 The external surface of the cerebral hemi- 
 spheres in reptiles, birds and several mammalia, 
 is smooth. The division into three lobes, how- 
 ever, is always marked by slight furrows, and 
 the individual parts are dissimilarly developed 
 in different situations. In the greater number of 
 the mammalia, as in man, the hemispheres are 
 convoluted, and furrowed to a greater or less 
 depth. 
 
 Of the Structure of the Convolutions , and of the 
 possibility of unfolding them. 
 
 The unfolding of the cerebral convolutions has 
 sometimes been considered as the essential point 
 in the anatomical discoveries of Dr. Gall and 
 myself. This is the reason why some have taken 
 particular pains in combating the possibility of 
 this operation. The fact is in itself of great im- 
 portance ; it affords several explanations that 
 particularly interest both physiology and patho- 
 logy. Many cases of disease would be quite in- 
 explicable without a knowledge of the structure 
 of the cerebral convolutions ; yet not this, but 
 the demonstration of the plurality of the nervous 
 instruments, their independent existence, and 
 
 M 2 
 
164 . 
 
 their connexions with each other, constitute the 
 essentials in our anatomical inquiries. 
 
 It has often been, and is still said, that the 
 vascular membrane, by plunging at intervals 
 among the white substance, to convey the blood- 
 vessels necessary for its nourishment, is the cause 
 of the cerebral convolutions and anfractuosities ; 
 but no part of the structure is thus mecha- 
 nical. The convolutions internally consist of 
 white fibres, which are covered on their extre- 
 mities with cineritious substance. These fibres, 
 which terminate the nervous bundles of the cere- 
 bral crura, are not all of the same length. Many, 
 especially of those which are situated on the outer 
 sides of the convolutions, terminate immediately 
 beyond the exterior walls of the cavities ; the 
 others extend to distances progressively greater 
 as they run more centrally, those of the interior 
 extending the farthest of all. It is in conse- 
 quence of this peculiar structure that prolonga- 
 tions and depressions are formed on the surface 
 of the hemispheres. The cineritious substance 
 follows all the forms composed by the white 
 fibres, and covers every elevation and depression 
 with a layer. 
 
 The fibres of analogous bundles are not pro- 
 longed in every individual to the same distance, 
 not even in the two hemispheres of the same 
 brain. I find that the parts which are most 
 largely developed have the fewest inequalities 
 
165 
 
 on the surface of the convolutions, the fewest de- 
 pressions, and even the smallest number of an- 
 fractuosities. They are simply voluminous, and 
 their peripheries are regular and smooth. 
 
 The convolutions are for the most part in- 
 clined slightly to the roof of the ventricles ; they 
 rarely stand up vertically. Their peripheral edge 
 is very frequently depressed, and this gives them 
 an appearance similar to that which a fold of 
 paper takes when its edge is pressed slightly in- 
 wards. (PI. ix. fig. 1 and 2.) 
 
 When a convolution is cut across vertically, the 
 white substance will be observed of greater thick- 
 ness at its bottom than at its top. This happens 
 from the nervous fibres losing themselves succes- 
 sively on either side in the cineritious enveloping 
 layer, whilst those of the centre only run to the 
 extremity. 
 
 A clean cut only shews the white substance of 
 the convolutions as a simple mass. No line of 
 separation can be perceived in any direction. 
 Nevertheless, it may be demonstrated to consist 
 of two layers covered externally by cineritious 
 matter. These layers meet in the middle line of 
 the convolutions, and are slightly agglutinated by 
 means of a very delicate nevrilema. 
 
 On this structure is founded the possibility of 
 separating, without injuring, the fibrous layers, 
 and thus of extending or unfolding each convo- 
 lution into a simple sheet. 
 
166 
 
 Before citing any anatomical evidence in sup- 
 port of the above fact, I shall give, as briefly as 
 possible, the history of its discovery. Dr. Gall 
 having had several opportunities of dissecting 
 hydrocephalic heads, found, as Morgagni had be- 
 fore him, the brain distended like a larsre blad- 
 der, several convolutions having entirely, and 
 others in part, disappeared. The internal sur- 
 face of the enlarged cavities was uniformly white; 
 and, generally, the nervous fibres and the blood- 
 vessels that accompanied them were distinctly 
 perceptible. He also met with a female, fifty- 
 four years of age, whose head was much en- 
 larged, without doubt in consequence of consider- 
 able dropsy of the brain. In person she was thin, 
 but she was as active and intelligent as women 
 usually are in her own sphere of life. Dr. Gall 
 being convinced that the brain is indispensable 
 to the intellectual manifestations, drew, as I have 
 said in the preface, the same inference as Tul- 
 pius had done before, viz., that the encephalic 
 mass cannot be disorganized or destroyed in 
 those persons who, being affected with hydroce- 
 phalus, still preserve their understanding en- 
 tire ; and farther, that the structure of the brain 
 must be different from Avhat is commonly sup- 
 posed. 
 
 The female, whose case is quoted above, hap- 
 pening to die of an inflammation of the bowels. 
 Dr. Gall found that the cerebral cavities con- 
 
167 
 
 tained about four pounds of pure and limpid 
 water. The convolutions of the upper part of 
 the forehead, and of the superior region of the 
 head, had disappeared entirely ; lower down, 
 however, they were distinct in different degrees. 
 In the interior of the great cavities, the fibrous 
 structure and the blood-vessels appeared very 
 conspicuous. I saw this head dissected at Dr. 
 Gall’s house, but neither of us at that time had 
 any definite idea of the mode in which the cavi- 
 ties had been enlarged, the convolutions oblite- 
 rated, and the cineritious substance made to ap- 
 pear spread over the entire surface, like an enve- 
 lope of nearly equal thickness. 
 
 This case, however, gave a new impulse to 
 our anatomical inquiries on the encephalon. We 
 began by attempting to imitate artificially the 
 state of the brain in hydrocephalus. Having 
 stripped off the pia mater, we insinuated our 
 fingers into the great cavities ; and by pressing, 
 more particularly against their posterior walls, we 
 found, with pleasure, that after overcoming a 
 slight resistance at the commencement, the con- 
 volutions separated along their interior, with all 
 readiness, into two parts. Even this rude expe- 
 riment made us conceive the possibility of the 
 gradually increased and unremitting pressure of 
 the water, as it accumulated in hydrocephalus, 
 unfolding the hemispheres into a membraneous 
 
168 
 
 sheet, without destroying any of the nervous 
 fibres. 
 
 By degrees our anatomical discoveries were 
 increased, and our ideas of the change effected 
 on the cerebral masses in hydrocephalus became 
 exact. 
 
 The imagination of Dr. Gall’s auditors was 
 somehow more struck by the experiment above 
 related, than by the whole of our cerebral ana- 
 tomy besides. Our opponents, by the same rea- 
 son, have conceived themselves particularly 
 called upon to disprove its practicability. In 
 their zeal, they have sometimes put sentences into 
 our mouths which we never uttered ; we have 
 been made to say, for instance, that the entire 
 brain could be unfolded into a membrane without 
 any laceration of fibres ; our idea has also been 
 travestied, by reporting that we regard each sepa- 
 rate convolution as a sort of little purse. 
 
 The question concerns the structure of the 
 convolutions only, and the possibility of proving 
 them composed of two distinct layers, separable 
 from each other. Let us, therefore, proceed to 
 the inquiry. 
 
 If a convolution be cut vertically across to its 
 base, a very gentle pressure with the finger on 
 the cut surface will suffice to separate its two 
 fibrous layers. The surfaces by which these were 
 agglutinated will, even after this rude procedure, 
 
169 
 
 remain perfectly smooth and equal. At the base 
 of the convolutions there is a mass which pre- 
 vents any further disjunction of their component 
 layers. Of the structure of this mass I shall 
 speak, when I treat of the commissures , or uniting 
 fibres of the cerebral parts. 
 
 If a portion of hemisphere, lying above the 
 ventricles, be taken in one hand, and the ventri- 
 cular surface be lightly pressed on by the other, 
 the mass at the base of the convolutions, which 
 has just been mentioned, will be torn, and the two 
 layers of the several convolutions then yield rea- 
 dily and maybe forced apart by the fingers. Whilst 
 this is doing, we may always observe a slight fur- 
 row along the line of every separation, and the 
 blood-vessels coursing along the same. Now this 
 could not happen, were not the convolutions 
 composed of two fibrous layers, not united by 
 transverse fibres, but simply agglutinated by 
 means of a fine and yielding cellular tissue. 
 
 If the convolutions be cut off externally to the 
 cavities, they may be readily unfolded, and with- 
 out any tearing of parts. 
 
 The convolutions, hardened in alcohol, in di- 
 luted nitric or muriatic acid, or in oil by simple 
 boiling, may also be unfolded with perfect ease 
 in the middle line, and only in the middle line of 
 their agglutination. No vestige of laceration 
 will there be perceived, but the fibrous expan- 
 
170 
 
 s on either side will become exceedingly dis- 
 tinct. 
 
 It is objected that the fibres may be separated 
 at every point, and by the side of the middle 
 line of the convolutions. Now this is as it ought 
 to be, because each layer is made up of many 
 fibres, running in one and the same direction. 
 The fibres of every ligament and muscle may be 
 parted in like manner ; but this fact does not do 
 away with the existence of entire ligaments and 
 muscles, distinct and easily separable from each 
 other. Moreover, the nervous fibres on the outer 
 surfaces of the layers, as they are continually and 
 successively dipping into the cineritious sub- 
 stance, may the more readily be separated from 
 each other, the more the bundles lie externally on 
 which the attempt is made. 
 
 To prove further that the convolutions consist 
 of two fibrous layers but slightly agglutinated, 
 the following experiment may be tried : — 
 
 Let a convolution be cut transversely, and 
 blown upon at random through a pipe ; both the 
 white and the gray substance may, although with 
 some difficulty, be destroyed ; but no disjunction 
 of fibres nor of the two substances will be ef- 
 fected. But let the stream of air be directed on 
 its middle line, and it will instantly be split from 
 the apex to the base. (PI. ix. fig. 1, 1 — 2.) If the 
 same experiment be made on a convolution that 
 
171 
 
 is slightly depressed at its summit, it will open 
 at the base by a simple cleft, but at the upper 
 part this will branch off towards the two corners. 
 (Pl. ix. fig. 1. 1 — 2.) 
 
 When, instead of air, water is thrown with a 
 syringe on a convolution cut transversely, the se- 
 paration is operated in a similar manner: this fluid 
 too, may be pushed for three or four inches along 
 the middle line, between the layers ; it will even 
 follow all the windings, and fill all the subdivi- 
 sions of the convolutions that occur in this space. 
 If after their injection the superior edge of the 
 convolutions be cut away longitudinally, to the 
 depth of about two lines, they will be found di- 
 vided into two equal parts ; and the manner in 
 which the fibres penetrate and lose themselves in 
 the cineritious substance on either side will also 
 be distinctly seen. 
 
 Water thrown with violence upon the outer 
 surface of a convolution will wash away the gray 
 and one half of the white substance ; as soon, 
 however, as it reaches the middle line, it will 
 penetrate to the right and left, and separate the 
 two layers to the extent of an inch or two each 
 way, as in the former experiment. Here also, as 
 in the former case, the direction and distribution 
 of the nervous fibres will be rendered very ap- 
 parent. 
 
 All these demonstrations prove incontestably 
 that the convolutions consist of two fibrous layers 
 
172 
 
 agglutinated together, and surrounded by cine- 
 ritious substance. Nevertheless, authors still 
 continue to speak of the cerebral pulp, or of the 
 medullary and pulpy substance of the convolu- 
 tions. But the idea of a mere pulpy matter is in 
 contradiction to all known anatomical and phy- 
 siological phenomena. Were the white sub- 
 stance pulpy, it would be destroyed or carried 
 away by a stream of air or water directed upon 
 it. It would be impossible, on the supposition 
 of a pulp, to account for the similar result of the 
 various experiments related, viz., the regular se- 
 paration of the convolutions into two layers along 
 the course of their middle line. 
 
 In connexion with the idea of a cerebral pulp, 
 that of hydrocephalus, to any considerable extent, 
 becomes an impossibility, because the slightest 
 distension of any one portion of the brain would 
 tear the pulp, and the disease could no longer 
 proceed. But many cerebral parts are often seen 
 completely unfolded, and still resisting the con- 
 tained fluid, although they be stretched into a 
 membrane scarcely two lines in thickness. Simi- 
 lar changes, too, are frequently undergone by the 
 majority of the convolutions, without any lacera- 
 tion or destruction of parts. 
 
 Some anatomists appear to have felt this diffi- 
 culty, and, to escape, have said that the cineritious 
 substance was very tenacious, even more so than 
 the white, and that this quality enabled it to re- 
 
173 
 
 sist laceration, and to suffer the expansion pecu- 
 liar to considerable hydrocephalus. 
 
 But all good anatomists know full well that the 
 cineritious is much softer than the white sub- 
 stance, that the first is never seen disposed in 
 layers, except where the last occurs in distinct 
 bundles; indeed, that in the very places where 
 the cineritious substance appears in layers, it falls 
 into pulp the moment the white fibres are taken 
 away. 
 
 In hydrocephalus, some anatomists have pre- 
 tended to see nothing more, no other change, than 
 a mere extension of the cerebral cavities. But 
 on this supposition, how may the entire disap- 
 pearance of the convolutions be explained 1 Were 
 the cavities merely distended, the convolutions 
 would only be separated more widely from each 
 other ; they would never be unfolded ; their com- 
 ponent layers would not, from a naturally vertical, 
 assume a horizontal position. 
 
 The structure of the convolutions once familiar, 
 however, we readily conceive a capacity in the 
 hemispheres to undergo great changes without 
 the occurrence of any actual disorganization. We 
 even perceive that when the cerebral fibres chance 
 to be elongated, this does not necessarily imply 
 derangement of intimate structure : vision is well 
 known often to remain perfect when the optic 
 nerve is very much lengthened. 
 
 Anatomy, consequently, shews how it comes 
 
174 
 
 that individuals affected with dropsy of the brain 
 may manifest all their intellectual and affective 
 faculties. We cannot now say with Walter, Ack- 
 ermann, and so many others, that in hydrocepha- 
 lus there is destruction or absorption of the orga- 
 nization, and that the mental functions are all 
 necessarily annihilated. The physiology of the 
 brain being now established, the existence of this 
 mass of organs is seen clearly to be indispensable, 
 and its disorganization impossible in those hydro- 
 cephalic persons, who exhibit affective and intel- 
 lectual faculties. All this is made evident by our 
 discoveries in anatomy and physiology. 
 
 It still remains for me to make some inquiries 
 into the comparative anatomy of the cerebral 
 hemispheres. To shew the presence of the brain 
 in the lower animals is not enough ; the particu- 
 lar organs that compose the hemispheres must be 
 determined in addition ; the resemblances to the 
 three cerebral lobes of the human kind, and to 
 the individual portions of each being also demon- 
 strated. Anatomists are not even agreed as to 
 the existence of the posterior lobes in all mammi- 
 ferous tribes. Messrs. Cuvier, Tiedemann, Serres, 
 and others, maintain that the posterior lobes of 
 the brain are only found in man and the quadru- 
 mana. They rest their opinion on the fact of the 
 cerebellum, in all the other classes, being unco- 
 vered by the brain. The conclusion here, how- 
 ever, is faulty, and the generally horizontal pos- 
 
175 
 
 ture of animals explains, in the most satisfactory 
 manner, why the cerebellum, instead of lying 
 under, is situated behind the posterior lobes. Let 
 me observe, once for all, that no part whatsoever 
 may be denied on account of mere difference of 
 configuration. Were it thus, the existence of the 
 front and middle lobes, in all the lower animals, 
 might also be disputed with perfect propriety. 
 The bulb of the olfactory nerve is covered by 
 certain cerebral parts, in man, monkeys, and the 
 phocse ; but in the generality of mammiferous 
 animals and birds, it lies, altogether, anterior to 
 the cerebral hemispheres ; nevertheless, no one 
 concludes that they, therefore, want the front 
 lobes. On the other hand, it is a great error to 
 assume with M. Series *, as an axiom, that — “ The 
 encephalon of all vertebral animals is constructed 
 after one uniform type, and with the same ele- 
 ments,” or with M. Cuvier f, to say that — “The 
 brains of the mammalia have the same parts as 
 that of man.” 
 
 In principle, I maintain that the cerebral he- 
 mispheres of animals are composed of a greater 
 or smaller number of parts, as different from each 
 other as the optic from the auditory nerves. The 
 existence of the posterior lobes of animals is not 
 to be doubted, seeing that the ganglion, out of 
 which they proceed (thalamus), is found in them. 
 
 * Anatomie du Ceryeau. t Anat. Comparee, t. ii. 
 
176 
 
 as well as in man. Moreover, the functions of 
 the human posterior cerebral lobes are also mani- 
 fested by animals. To the above, it is still ne- 
 cessary to add, that variety in the peripheral 
 expansions of individual organs, indicates neither 
 the absence nor presence of any one in particular: 
 one hemisphere that is entirely smooth, and ano- 
 ther that is furrowed in all directions, may both 
 of them contain the same elementary parts. This 
 consideration it was which induced me to say, 
 that the comparative anatomy of the brain could 
 not be advanced without the assistance of physi- 
 ology. With the aid of physiology, however, 
 discoveries of great interest might, undoubtedly, 
 be made. The analogy that exists between the 
 brains of the cat family (pi. iv. fig. 5), of the dog 
 tribes (pi. iv. fig. 6), of the sheep, monkey, and 
 other kinds, is as striking as the general similarity 
 of disposition and character of each. The same 
 law holds in the case of man. Individual organs, 
 however, are more or less developed in every 
 species of the same genus. In pi. v. fig. 1 and 2, 
 I have given representations of the brains of two 
 species of monkey. They are, evidently, much 
 alike considered in general; but still, the ante- 
 rior lobes in fig. 1, are smaller, comparatively, 
 than in fig. 2. The brain of the ourang-outang is 
 figured in the same plate, fig. 3 and 4, and the 
 brain of an idiot girl, fig. 5 and 6. There is a 
 striking general resemblance between the two, 
 
177 
 
 yet the front lobes of the ourang-outang are more 
 considerable than those of the idiot. In a pre- 
 cisely similar manner are the different constituent 
 parts of the healthy human brain dissimilarly de- 
 veloped, and their specification is matter of espe- 
 cial interest in the study of man. 
 
 N 
 
178 
 
 Section VII. 
 
 Of the Commissures or Fibres of Union. 
 
 All the proper cerebral organs, like the other 
 instruments of phrenic life, occur in pairs, or are 
 double, from the medulla oblongata up to their 
 expansion in the convolutions. This, probably, hap- 
 pens because of their importance, and to the end, 
 that the congenerate parts may supply each other’s 
 places, should either chance to be injured. But in 
 addition to the parts already described, there are 
 others still that contribute to the formation of the 
 brain. These have been long known by the 
 name of commissures. 
 
 Anatomists speak of the great commissure or 
 corpus callosum, and of the anterior, middle, and 
 posterior commissures of the brain. Until Dr. 
 Gall and I published, it was the custom to take 
 merely mechanical views of these, without at- 
 tempting to discover their relations with the other 
 cerebral parts, their derivations, or the causes 
 of their dissimilarity in different animals, and this 
 too, although Vicq d'Azyr had said* that “the 
 commissures seemed to exist for the purpose of 
 establishing sympathetic communications between 
 the different parts of the brain.” 
 
 The successive additions made to the diverg- 
 ing bundles, in their course from the medulla 
 * Memoires de l’Acad. des Sciences de Paris, 1781. 
 
179 
 
 oblongata to the convolutions, is a point in ana- 
 tomy that is now generally admitted. I conceive 
 that I have discovered another or second order of 
 fibres, which, with Dr. Gall, I distinguish by the 
 title, converging fibres, or apparatus of union. 
 This discovery, however, is disputed. M. Tiede- 
 mann calls it a chimera *. Dr. Gall, in the sixth 
 volume of his work, in 8vo., on the Functions of 
 the Brain, replies at great length to M. Tiedemann, 
 and to those who dispute the converging fibres. 
 For my part, I here address the same reproach to 
 M. Tiedemann, which I have laid against him 
 in another place, and in a general manner. He 
 has admitted laws from researches made on the 
 brain of the embryo, which are in contradiction 
 with the structure demonstrable in the adult. 
 
 Nothing can be easier than, by dissection, to 
 prove the two orders of cerebral fibres: the di- 
 verging and the converging, and to shew that the 
 mass or bundle called corpus callosum belongs to 
 the converging order. 
 
 The corpus callosum extends anteriorly and 
 posteriorly beyond the striated bodies. (PI. x. 
 fig. 1.) Its thickness, at either extremity, is 
 greater than at its middle. (PI. vii. fig. 2, x, ju..) The 
 fibres which compose the folds of the corpus cal- 
 losum, proceed evidently from the convolutions 
 which form the most anterior and posterior parts of 
 the hemispheres, and by no means from the tha- 
 
 * Bildung's-geschichte des Gehirns, Niirnberg, 1816, p. 156. 
 
 N 2 
 
180 
 
 lami and striated bodies. (PI. x. fig. 1, 39 and 40.) 
 Their direction, consequently, is entirely differ- 
 ent from that of the bundles constituting either 
 of the two great cerebral ganglions. If the fibres 
 of the supposed thalami be followed towards the 
 posterior lobes, by scraping the parts, the converg- 
 ing fibres may readily be observed passing out 
 betwixt them. (PI. x. fig. 1, P.) Moreover, the 
 two folds (ib, 39 and 40) of the corpus callosum 
 are always proportionate in size to the fissures 
 that part the hemispheres before and behind, or 
 otherwise, to the convolutions on either side of 
 the fissures, but by no means to the diverging 
 fibres. The corpus callosum is softer and much 
 larger than the bundles of the striated bodies ; 
 the fibres of either of these masses, consequently, 
 cannot be mere continuations of the other. 
 
 But, in fact, the entire difference of the two 
 orders of fibres cannot possibly be called in ques- 
 tion, saving at the middle of the corpus callo- 
 sum, or place opposite the striated bodies ; and 
 even here, the analogy that exists between the 
 middle and the extremities of the mass, may be 
 assumed a sufficient index of an analogous forma- 
 tion. The scalpel, however, sets the matter com- 
 pletely at rest. The converging mass, I must not 
 forget to state, does indeed communicate with 
 the great cerebral ganglions, by means of a 
 superficial band or layer, which has obtained the 
 title of semicircular tape-worm. On examining 
 
181 
 
 the middle part of the corpus callosum attentively, 
 its edge, opposite the great celebral ganglions, 
 will be seen to consist of this semicircular band 
 alone. It is composed of its own fibres, so to 
 say, and increases in thickness as the middle line 
 is approached, for the fibres become gradually 
 thicker till they meet, in the same way as the 
 folds increase, as they advance on each side to 
 their junction. 
 
 In attempting to imitate the naturally unfolded 
 state of the brain in hydrocephalus, by pressing 
 upon the roof of the cavities with the fingers, a 
 certain quantity of resistance is always expe- 
 rienced at the bottoms of the convolutions. This 
 proceeds from a tissue formed by the interlace- 
 ment of the two orders of cerebral fibres. This 
 tissue once torn, the line between the layers of 
 the convolutions is entered immediately, and 
 they are then unfolded with perfect ease. 
 
 Were the diverging fibres or bundles of the 
 great cerebral ganglions prolonged directly into 
 the corpus callosum, it would be extremely diffi- 
 cult to understand how they could be elongated 
 to the degree occasionally observed in hydroce- 
 phalus. The disappearance of the convolutions 
 too, would be altogether incomprehensible ; the 
 water would act against the corpus callosum and 
 the walls of the cavities, but there would be no 
 reason for the unfolding of the convolutions. 
 With the true structure in view, however, all that 
 
182 
 
 happens in hydrocephalus is easily explained ; 
 there is neither absorption nor increase of the 
 cerebral parts ; the converging and diverging 
 fibres have but to change positions ; to separate at 
 the place of their intersection, at the bottoms of 
 the convolutions ; the convolutions to split in the 
 line of their component layers, and the change is 
 completed. I, for my own part, feel inclined 
 rather to recognise increase than diminution of 
 the cerebral mass in hydrocephalus. Why, indeed, 
 should not that happen in regard to the brain 
 which so plainly occurs as the investing mem- 
 branes are concerned ? How greatly is not the 
 arachnoid coat, the dura mater, and even the os- 
 seous covering of the whole augmented? All 
 concurs then to prove the presence of two or- 
 ders of fibres in the brain as well as in the cere- 
 bellum. 
 
 And now a question of much interest presents 
 itself ; it is this : are the bundles styled corpus 
 callosum and annular protuberance, true commis- 
 sures or organs of union ? It is quite certain that 
 the annular protuberance belongs to the la- 
 teral parts of the cerebellum, and that it appears 
 with, and is proportionate to, these. It is also 
 undeniable, that the corpus callosum is in rela- 
 tion to the cerebral hemispheres, precisely as is 
 the annular protuberance to the lateral parts of 
 the cerebellum. We have seen too, that both 
 the brain and cerebellum are composed of two 
 
183 
 
 orders of fibres. On the other hand, the nervous 
 apparatus of animal life is universally double, and 
 united in the middle line by means of commis- 
 sures. I believe, indeed, that the law of com- 
 missures is quite general ; but I doubt of each 
 congenerate pair of fibres having its own com- 
 missure, or bundle uniting in the middle line. 
 This, in the first place, cannot possibly be the 
 case in the spinal cord and medulla oblongata, 
 because the apparatus of union is there much 
 less considerable than the several halves of these 
 masses. The same thing may be said in regard 
 to the annular protuberance and corpus callosum. 
 These bundles, compared with the white masses 
 of the cerebellar and cerebral hemispheres, are 
 much too inconsiderable. It would seem, there- 
 fore, that a small mass is sufficient to unite the 
 two congenerate halves. Still, the mass that 
 unites, and the mass that is united, not being of 
 equal dimensions, does not gainsay the possibility 
 of the commissures being proportionate to the 
 congenerate parts that are joined. 
 
 M. Serres maintains *, that the corpus callo- 
 sum is proportionate to the annular protuberance, 
 and that the hemispheres of the brain are deve- 
 loped in the direct ratio of those of the cere- 
 bellum. It is easy to demonstrate this error. 
 The masses mentioned vary extremely, and are 
 never developed directly in the ratio of each 
 * Rapport, &c., p. 72. 
 
184 
 
 other, neither in different kinds, nor in different in- 
 dividuals of the same kind of animals. To be con- 
 vinced of this truth, it is enough to glance over 
 the tables of the comparative sizes of the brain 
 and cerebellum, which various authors (among the 
 number M. Cuvier) have drawn up. The pro- 
 portion between the brain and cerebellum even 
 varies in the same individual at different periods 
 of life. The cerebellum attains its complete 
 growth later than the cerebral parts generally. 
 
 As to the proportion between the annular 
 protuberance and cerebellar hemispheres, and 
 that between the corpus callosum and hemi- 
 spheres of the brain, recognised by M. Serres, 
 these are facts announced by Dr. Gall and me, 
 long before this gentleman’s publication ap- 
 peared. 
 
 It still remains to be seen, whether or not 
 the annular protuberance and corpus callosum 
 are true commissures. These parts are only 
 found in man and the mammalia ; in birds, rep- 
 tiles, and fishes, they are wanting. Birds and 
 reptiles, however, have undoubtedly cerebral he- 
 mispheres, with two great ganglions ; and, as in 
 them, the other commissures, entitled anterior, 
 middle, and posterior, are of a size proportionate 
 to the lateral masses, and are situated as in man 
 and other superior tribes, they cannot be assumed 
 to supply the place of the corpus callosum. It 
 follows, therefore, either that the union of the 
 
185 
 
 cerebral hemispheres of birds is established ac- 
 cording to another law than that of the mam- 
 malia, or that the annular protuberance and 
 corpus callosum are not true commissures, in 
 which event they would have to be considered as 
 mere constituent parts of the cerebellar and ce- 
 rebral apparatus. Dr. Gall and I committed an 
 error in the first volume of our large work, when 
 we treated of a part in birds, as analogous to 
 the corpus callosum of quadrupeds. In the suc- 
 ceeding section of this book I shall show that the 
 mass in question corresponds, not to the corpus 
 callosum, but to the fornix of mammiferous ani- 
 mals. There, too, I shall prove that we did 
 wrong, in classing the entire fornix among the 
 commissures. 
 
 My doubts of the propriety of regarding the 
 annular protuberance and corpus callosum as 
 commissures, increase in consequence of the 
 existence of two longitudinal bands, running 
 along the middle line of the latter, forming what 
 is called its raphe (pi. x. fig. 1), and of the 
 layer of fibres between the raphe, and between 
 the two halves of the annular protuberance, simi- 
 lar to that which occurs between the peduncles 
 of the brain. (PI. vii. fig. 2, A, p., x.) 
 
 Lastly, Reil relates a remarkable case * of a 
 woman, above thirty years of age, whose intel- 
 lectual faculties were very limited, and whose 
 * Archiv fur die Physiologie, B. ii. S. 341. 
 
186 
 
 corpus callosum was found split in the middle 
 line through its entire length. 
 
 Last year, (1825,) through the kindness of 
 Messrs. Morgan and Keys, surgeons to Guy’s Hos- 
 pital, London, I had an opportunity of seeing a 
 similar case. The name of the man in whom it 
 occurred was James Cardinal, a portrait of whom 
 I gave, in 1815, in my work, entitled « The Phy- 
 siognomical System,’ which Dr. Gall copied in 
 his continuation of our large work, and which I 
 myself re-published last, year in my book on 
 Phrenology. I do not think that any case more 
 remarkable than James Cardinal’s has ever been 
 the subject of observation. He bad hydroce- 
 phalus to an enormous amount, and manifested 
 the affective and intellectual faculties. The 
 greater part of the water was accumulated be- 
 tween the brain and dura mater, but the lateral 
 cavities were at the same time distended by about 
 a pint of fluid, which communicated freely with 
 the liquid collected without the brain, as the 
 corpus cailosum, with its extreme folds, was 
 split through its entire length along the median 
 line. Its masses on either side, together with 
 the lateral convolutions, were quite distinct. The 
 union of the corpus callosum from this would not 
 appear essentially necessary to the unity of func- 
 tion of the two cerebral hemispheres. Never- 
 theless, I regard the corpus callosum, as well as 
 the convolutions, necessary to produce an organi- 
 
187 
 
 zation fitted for its peculiar functions. This 
 structure, perhaps, has some advantages as the 
 vegetative functions of the parts are concerned ; 
 it may possibly have the same end as the cavities 
 and anfractuosities, of which I shall speak more 
 particularly by-and-by. 
 
 With the exception of regarding the corpus 
 callosum as an apparatus of union, I see no reason 
 to alter any of the other ideas relative to this 
 mass, published by Dr. Gall and me in our Me- 
 moir to the French Institute in 1808, and in the 
 first volume of our large work ; I still maintain 
 the proportions between its different parts and 
 diverse cerebral masses ; the dissimilar course 
 of the diverging and converging fibres ; the accu- 
 mulation of fibres at its two extremities, in con- 
 sequence of the anterior and posterior fissures of 
 the hemispheres. The direction of the fibres 
 forming the raphe, will, perhaps, be better ex- 
 plained in the succeeding section, which treats 
 of the communication of the nervous appara- 
 tuses. The structure of the raphe appears to 
 be more analogous to that of the fimbriated body, 
 or its slip communicating with the fornix, and of 
 the semicircular tape-worm of Haller ( lamia semi- 
 circular is ). 
 
 The idea formed of the folds of the corpus 
 callosum, depends on the view that is taken of 
 the mass lengthwise and from above. Anato- 
 mists, contemplating it in this way, have ima- 
 
188 
 
 gined that it was folded down upon itself before 
 and behind, in consequence of the prolongation of 
 the cavities into the anterior and posterior lobes 
 between the superior and inferior masses of con- 
 volutions. 
 
 The error of classing the fimbriated body and 
 the entire fornix among the apparatuses of union 
 is evident. To be convinced of the mistake, it 
 is enough to remember the direction of the fibres 
 composing these parts. The bundles of neither 
 ever cross the median line ; they always run into 
 lateral masses, and are undoubtedly instruments 
 of communication. 
 
 In the mammalia, there lies a band upon the 
 medulla oblongata behind the annular protube- 
 rance, which Dr. Gall and I have regarded as a 
 commissure of the auditory nerves. Our view in 
 this particular may be disputed, and I leave the 
 point still undetermined. The band, however, 
 is certainly in connexion with the auditory 
 nerves. 
 
 Let us now treat of the undoubted fibres of 
 union, or of the true commissures. And, first, the 
 nervous masses of the vertebral column are con- 
 nected in the median line by a peculiar order of 
 fibres. (PI. i. fig. 6, 9.) 
 
 In the fourth ventricle of fishes, especially of 
 those in which the lateral edges of this cavity 
 resemble ganglions, certain transverse fibres may 
 be distinctly seen behind and before the median 
 
189 
 
 ganglion, and uniting the tsvo cerebral halves. 
 (PI. ii. fig. 13, e, e.) 
 
 I am much inclined to think that the nervous 
 instruments are principally connected at their 
 origins. The two halves of the cerebellum of 
 all vertebral animals, for instance, are united by 
 transverse fibres running between the two pri- 
 mary bundles that come from the sides of the 
 medulla oblongata. In the sturgeon, frog (pi. iii. 
 fig. 2), and other fishes, and reptiles, where the 
 cerebellum is so small, there is a thin white slip 
 which joins the two sides together. In other 
 fishes (pi. ii. fig. 13), and reptiles, whose cere- 
 bellum is larger, as also in birds, we may per- 
 ceive a white layer at the bottom of the cerebel- 
 lar ventricle, terminated in birds at its anterior 
 edge by a small tubercle. (PI. iii. fig. 8, 43.) A 
 similar apparatus is found in man, and in all 
 mammiferous animals. 
 
 The cerebellum is at a greater or smaller dis- 
 tance from the bigeminal or quadrigeminal bo- 
 dies. This accounts for the different lengths of 
 the part styled valve of Vieussens, which consists 
 of a thin slip of fibres running transversely be- 
 tween the cerebellum, the edges of the primary 
 bundles that expand into the organs of the affec- 
 tive faculties, and the bigeminal or quadrigeminal 
 bodies. (PI. xi. fig. 1, y.) 
 
 To shew the interior of the fourth ventricle, 
 the union of the two cerebellar hemispheres, and 
 
190 
 
 the Vieussenian valve in man and the mammalia, 
 the brain must be laid on its superior surface (pi. 
 vi. fig-. 1), the annular protuberance and the me- 
 dulla oblongata separated, and the two halves 
 pushed aside. 
 
 In fishes there is scarcely a part analogous to 
 the valve of Vieussens. This happens from the 
 vicinity of the cerebellum and the other ganglions. 
 In birds, however, the part is very distinct. (PI. 
 iii. fig. 6, and pi. xi. fig. 3, y.) 
 
 Behind the bigeminal bodies in birds (pi. xi. 
 fig. 3), and the quadrigeminal bodies in the 
 mammalia and man (pi. xi. fig. 1), at the point 
 where the nerve of the superior oblique eye-mus- 
 cles goes off (ibid. 13), there is a transverse 
 uniting band. 
 
 The bigeminal or quadrigeminal bodies are 
 always united by commissures or transverse 
 bands. (PI. iii. fig. 6, and pi. xi. fig. 1, 2, 3, x.) 
 The body called pineal gland is always found in 
 animals possessed of the great inferior ganglion 
 of the brain (thalamus). I do not believe that it 
 occurs among fishes. M. Tiedemann entertains 
 the same opinion ; but M. Serres * declares, that 
 the pineal gland is to be demonstrated in all the 
 four classes of vertebral animals. According: to 
 him, the body has two sets of peduncles, one 
 issuing from the optic thalamus, another from 
 
 * Rapport, &c., p. 69, 70. 
 
191 
 
 the quadrigeminal tubercles. He, however, is 
 in evident contradiction with himself when he 
 adds, that the thalamus does not exist in fishes. 
 
 Anatomists now-a-days are agreed as to the 
 part in question being no gland, but a nervous 
 mass composed of white and cineritious sub- 
 stance. Its form and size vary extremely in dif- 
 ferent classes of animals. It always lies between 
 the true optic and the great inferior ganglions of 
 the brain. It has four connecting slips, two on 
 either side. The posterior pair run backwards 
 and downwards, and adhere to the proper gan- 
 glions of the optic nerves. (PI. vii. fig. 2, and 
 pi. x. fig. 1, B. s.) 
 
 It is at the fore-part of the pineal gland that the 
 granular concretions which have attracted so 
 much notice are principally found. Malacarne * 
 says, that he has seen them in the pineal gland 
 of a goat, and Soemmerring f , that he has de- 
 tected them in that of a fallow deer. 
 
 Des Cartes is generally known to have con- 
 sidered the pineal gland as the seat of the soul. 
 At the present day, it were useless to repeat the 
 arguments that Steno | has employed against the 
 Cartesians in refutation of their error. 
 
 I only speak of the pineal gland in this place 
 
 * Encephalotomia di alcuni Quadvupedi, Mantua, 1795. 
 
 t Vom Him und Ruckenmark, Maynz, 1/88. 
 
 X Discourse on the Anatomy of the Brain, inserted in Win- 
 slow’s Anatomy. 
 
192 
 
 for the sake of connexion, for it appears to be- 
 long, at least, as much to the instruments of 
 communication as to those of union. 
 
 The part which, by anatomists, is entitled pos- 
 terior commissure, is found lying anteriorly to 
 the proper optic ganglion, and at the commence- 
 ment of the great inferior ganglion of the brain, 
 into which it plunges immediately. (PI. iii. fig. 
 9, pi. vii. fig. 2, and pi. xi. fig. 1, ».) 
 
 The transverse fibres, usually termed the soft 
 or middle commissure, may be readily seen ex- 
 tending between the great inferior cerebral gan- 
 glions in the mammalia. (PI. xi. fig. 1, 46.) Many 
 authors have doubted the existence of this part 
 in man. It may unquestionably be demonstrated 
 in the human brain, but its very delicate fibres 
 are easily torn, and care is required in the attempt 
 to point it out. But it may be most readily shewn 
 from below by separating the crura, the annular 
 protuberance, and the medulla oblongata. 
 
 I now come to a commissure that is quite con- 
 stant in all vertebral animals. In man, it is called 
 the anterior commissure. Its regular occurrence, 
 like that of the posterior commissure and uniting 
 fibres of the quadrigeminal or bigeminal bodies, 
 is an index of its importance. In the eel (pi. ii. 
 fig. 1), and barbel (ib. figs. 12 and 13), it lies be- 
 tween the second pair of ganglions, beginning the 
 reckoning from before (ib. fig. 13, 61) ; in the floun- 
 der (ib. fig. 4), the roach (ib. fig. 11), and others, it 
 
193 
 
 is situated between the olfactory ganglions. In all 
 the animals possessed of striated bodies, viz. rep- 
 tiles, birds, and the mammalia, it always lies an- 
 teriorly to the junction of the optic nerves. It 
 traverses the striated bodies, and is continued on- 
 wards between the anterior and middle lobes. 
 (PI. iii. figs. 6 and 9 ; pi. viii. figs. 1 and 2, and 
 pi. xi. figs. 1 and 2, 61.) 
 
 In all the mammalia, the anterior commissure is 
 composed of two parts : the one of these commu- 
 nicates with the olfactory nerve, the other, as in 
 man, is prolonged towards the fissure of Sylvius 
 between the anterior and middle lobes. This 
 discovery I published in the spring of 1821, in 
 a thesis, entitled Encephalotomie *. The portion 
 running to the olfactory nerve forms an arc, the 
 convexity of which is turned backwards, the con- 
 cavity forwards. (PI. iv. fig. 4, 31.) 
 
 In man, the anterior commissure traverses the 
 exterior half of the striated bodies ; it communi- 
 cates first with the innermost convolutions of the 
 anterior lobes, then with those situated at the 
 bottom of the Sylvian fissure, and lastly, with those 
 in the fore part of the middle lobe. It thus forms 
 an arc, whose longest and concave edge is directed 
 backwards. (PI. viii. fig. 2, 61.) 
 
 M. Chaussier f and M. Tiedemann regard 
 the anterior commissure as a continuation of 
 
 * Vide p. 23. t Anatomie du Cerveau, p. 71. 
 
 % op. cit.,p. 138. 
 
 o 
 
194 
 
 the cerebral crura. Anatomy exposes this error. 
 Having laid the brain on its superior surface, (pi. 
 vi. fig. 1, and pi. viii. fig. 2,) turn back the optic 
 nerves and separate the hemispheres slightly, a 
 white cord about the thickness of a writing-pen 
 will be brought into view. Remove the super- 
 imposed parts without implicating the anterior 
 commissure itself, and its passage across the stri- 
 ated bodies will be distinctly perceived. Arrived 
 at the anterior extremity of the middle lobes, the 
 anterior commissure divides into a great number 
 of filaments that communicate with the convolu- 
 tions. I shall bring this section to a close, by 
 proposing the following question : — Is the ante- 
 rior commissure proportionate to the cerebral 
 masses destined to the intellectual faculties ? 
 
195 
 
 Section VIII, 
 
 Of the Communications of the Nervous Apparatuses , 
 
 Thus far advanced, we have seen that the nervous 
 system is an aggregation of organs performing 
 special functions ; that the instruments of phrenic 
 life exist in pairs, and that there is a particular 
 structure, by which congenerate parts are united. 
 Another essential consideration refers to the com- 
 munication with each other of the peculiar nervous 
 apparatuses, an arrangement which is indispensa, 
 ble to account for the mutual influence, or, as it 
 is termed, the sympathies of the functions. 
 
 The functions of the thoracic and abdominal 
 viscera are evidently mutually influential, and 
 the nerves of vegetative life, generally, communi- 
 cate together. Again, vegetative and phrenic life 
 are mutually related; imperfect digestion, for 
 example, disturbs the intellectual energies, and 
 excessive mental application, or moral sadness, 
 interrupts the process of digestion. The commu- 
 nications between the nerves of the thorax and 
 abdomen, and the anterior roots of the spinal and 
 cranial nerves, especially the pneumogastric, the 
 hypoglossal, the abductor, the facial, and the tri- 
 geminal, are well known anatomical facts. 
 
 Further, the spinal nerves are intimately con- 
 
 02 
 
196 
 
 nected with each other ; there are longitudinal 
 bands that run along the edges of the two fissures 
 of the spinal cord ; these are, especially, evident 
 on the dorsal aspect of the cervical portion (pi. 
 i. fig. 5.), and on each side, at the bottom of the 
 dorsal fissure. (PI. i. fig. 7.) The nerves of volun- 
 tary motion and of sensation are also most inti- 
 mately connected. 
 
 Moreover the nerves of motion, of general sen- 
 sation, and of the various special sensations, taste, 
 smell, hearing, and sight, communicate with each 
 other. 
 
 The mutual influence of the organs of motion, 
 of the external senses, and of the affective and 
 intellectual faculties, equally require an organic 
 communication. The physiological experiments 
 or mutilations which have been made in reference 
 to this subject, are not, by any means, satisfac- 
 tory. The cerebellum, which, according to M. 
 Rolando, gives the locomotive power, and to 
 M. Flourens, regulates the motions, is in more 
 intimate connexion with the dorsal than with the 
 abdominal roots of the spinal nerves ; yet M. Ma- 
 <rendie has been led to conclude that the dorsal 
 
 o 
 
 roots of these nerves preside over sensation, whilst 
 the abdominal are the special organs of motion. 
 It is, however, certain that the external senses 
 and the organs of motion, aid, to a greater or less 
 amount, the cerebral functions, properly so called. 
 It is to this end, consequently, that the nervous 
 
197 
 
 masses of motion, and those of general and 
 special sensation, communicate with the organs 
 of the affective and intellectual faculties. This 
 communication is established by means of the 
 medulla oblongata, the decussation of some of 
 whose component bundles, explains the effects of 
 cerebral injuries being frequently manifested on 
 the side of the body opposite to that on which 
 they occur. 
 
 The sense of taste is subservient to the functions 
 of digestion and nutrition, and its instrument is a 
 branch of the trigeminal, a nerve of general sen- 
 sation, supplying the organs of mastication, and 
 arising very nearly from the same place as 
 the glossopharyngeal, the pneumogastric and the 
 facial. 
 
 The auditory nerve embraces the primary bun- 
 dles of the organs of the affective powers, and 
 these it assists more generally, especially among 
 animals, than those of the intellectual faculties : 
 males and females call on each other as the season 
 of love draws near ; the cries of the young bring 
 the mother to their aid ; the barking of the dog, 
 the grunting of the hog, the crying of the monkey, 
 collect other individuals of their several kinds to 
 render assistance ; all the animals that plant sen- 
 tinels, know the sounds of alarm ; and the courage, 
 secretiveness, or circumspection of many species 
 is excited by peculiar tones, appreciated by the 
 sense of hearing. The cock taunts his adversary 
 
198 
 
 by crowing ; the sparrow, turkey, common fowl, 
 and many other kinds of birds advise their young 
 of an enemy’s approach, and by their cries admo- 
 nish them to keep quiet, or to seek security by 
 flight. 
 
 The optic nerve aids almost all the affective and 
 intellectual faculties. Instead of running directly 
 from its origin to the eye, it therefore turns out- 
 wardly, and, in its course, communicates with all 
 the parts adjacent, from its ganglion, onwards, to 
 the tuber cinereum ; so that in order to turn it 
 back in man, it must be torn away from a thin com- 
 municating layer all the way along its outer edge 
 as far as the external geniculated body. Phre- 
 nology shews that vision assists more immediately 
 those organs situated backwardly, laterally, and 
 anteriorly, than those in the middle line of the 
 head, such as veneration, firmness, hope, justice, 
 &c. In all animals, the optic nerve is, evidently, 
 connected with a great number of cerebral masses. 
 
 The nerve of smell always communicates with 
 the anterior cerebral lobes, and in animals this 
 sense aids in a very particular manner the facul- 
 ties that know external objects, their qualities, 
 their relations, and the phenomena they pre- 
 sent. Animals examine their food, their friends, 
 their enemies, their dwellings, &c. &c., by means 
 of smell. 
 
 The olfactory nerve also communicates with 
 the anterior convolutions of the middle lobes, 
 
199 
 
 especially with the part that corresponds to the 
 hippocampus’s foot, or the ammons’ horn. If 
 there be a cerebral part presiding over the func- 
 tions of hunger and thirst, it would appear to be 
 situated in this neighbourhood. I am confirmed 
 in this supposition by the vicinity of the organ of 
 destructiveness. 
 
 To conclude, nature has taken great pains to 
 establish an intimate connexion between the dif- 
 ferent cerebral parts themselves. Two longitudi- 
 nal bands, running at the bottom of the dorsal 
 fissure of the spinal cord, are continued into the 
 fourth ventricle. In fishes they run as far as the 
 olfactory ganglions. (PI. ii. fig. 13.) 
 
 The cerebellum, as I have already shewn, al- 
 ways communicates with the medulla oblongata, 
 and the bigeminal or quadrigeminal bodies. 
 
 The parts successively added to form the cere- 
 bral hemispheres are connected together by trans- 
 verse bands or interlacing fibres. A band of this 
 nature is sometimes seen below the olivary bo- 
 dies. (PI. viii. fig. 2, 64.) Different other trans- 
 verse interlacements are visible in every human 
 brain that is moderately consistent, 1st, at the 
 superior edge of the annular protuberance (pi. 
 viii. fig. 1, 33) ; 2ndly, in the middle of the cere- 
 bral crura (pi. vi. fig. 1, and pi. viii. fig. 1, 34) ; 
 3rdly, below the optic nerve (ib. fig. 1, 35); 
 4thly, at the place where the fibres issue to enter 
 the superior convolutions of the middle lobe 
 
200 
 
 (pi. viii. fig. 1, 36) ; 5thly, between the two great 
 cerebral ganglions (ibid. 37) ; 6thly, at the exter- 
 nal edge of the striated bodies (pi. viii. fig. 1, and 
 pi. ix. fig. 1, 38). These interlacing bundles do not 
 occur on the external surfaces only, they also pe- 
 netrate the interior of the masses to which they 
 belong. 
 
 The greater part of the fornix, that is to say, the 
 fimbriated bodies running from the hippocampus’s 
 foot, the posterior and anterior pillars, and the 
 longitudinal fibres between them, as also the 
 mammillary bodies and their prolongations, are 
 evidently apparatuses of communication. (PI. x. 
 fig. 1, B. 57 — 62.) The anterior pillars of the fornix 
 traverse the tuber cinereum, and plunge into the 
 mammillary bodies, from whence another bundle 
 issues, to be lost in the great ganglion of the or- 
 gans of the affective faculties (thalami). (PI. x. 
 fig. 1, 16.) In the mammalia the fornix further 
 communicates with the two longitudinal bands of 
 the corpus callosum (raphe), and with the sep- 
 tum lucidum, which last in its turn communicates 
 with the raphe, and with a band lying before the 
 optic nerves. (Ibid. 57, 58, 59.) The raphe itself, 
 and also the semicircular tape-worm of Haller 
 (pi. xi. fig. 1, A. 32), appear to be instruments of 
 communication, the first between the converging 
 fibres themselves, the other between the great ce- 
 rebral ganglions and the converging fibres. 
 
 These parts are strikingly analogous in all the 
 
201 
 
 mammalia. In birds and reptiles there are fibres, 
 which, from the middle lobes, the contours of the 
 posterior lobes, and from the median line, come 
 together towards the base of the brain, and form 
 a bundle that communicates with the cerebral 
 crura behind the optic nerves. This fibrous layer, 
 or bundle of birds, consequently, resembles the 
 fornix and septum lucidum of mammalia. (PI. iii. 
 fig. 6, and pi. xi. fig. 3, B. 60.) 
 
 In fishes, besides the two longitudinal bands 
 that run the whole length of the encephalic 
 masses, each ganglion sends a slip of communica- 
 tion to its neighbour, the cerebellum to the optic 
 ganglion, this to the succeeding one, and so on 
 successively, whilst the most anterior of all sends 
 fibres to join the common longitudinal band of 
 the olfactory nerves. (PI. ii. fig. 13.) 
 
 The mass entitled infundibulum lies behind 
 the junction of the optic nerves. It is evidently 
 traversed by white filaments, and communicates 
 with the tuber cinereum. (PI. ii. fig. 4, 6, 8 ; pi. 
 iii. fig. 12; and pi. vi. fig. 1, 17.) 
 
 The influence of the anterior pyramidal bodies 
 on the propagation of the will, towards the instru- 
 ments of motion, deserves some attention. Ac- 
 cording to phrenological observations, the anterior 
 lobes of the brain contain the organs of the per- 
 ceptive and reflective intellectual faculties, with- 
 out which there would be no will *. Now these 
 * See Philosophical Principles of Phrenology, Lond. 1825, p. 32. 
 
202 
 
 lobes are intimately connected with the pyra- 
 midal bodies, and these last communicate directly 
 with the abdominal half of the spinal cord, 
 whence, as it appears, the nerves especially ap- 
 propriated to propagate the will are detached. 
 
 Lastly, in the animals whose brains are smooth 
 on the surface, the peripheral connexion of the 
 individual organs is manifest ; in the other kinds, 
 whose brains are convoluted, it is extremely inte- 
 resting to trace the connexion of the different 
 cerebral masses composing special instruments. 
 These connexions explain the mutual influence 
 of the faculties. The organs of analogous powers 
 are regularly in each other’s vicinity ; the convo- 
 lutions that compose them even run into each 
 other. The organ of philoprogenitiveness com- 
 municates with that of inhabitiveness, and with 
 that of courage; the organ of courage also commu- 
 nicates with that of attachment, and with that of 
 destructiveness ; the organ of seeretiveness com- 
 municates immediately with that of destructive- 
 ness, and with that of circumspection ; the organ 
 of benevolence communicates with the organ of 
 veneration ; the organ of firmness is in communi- 
 cation with those of all the faculties around it — 
 veneration, justice, and self-esteem ; the organ 
 of justice runs into that of the love of acquiring — 
 this is connected with that of construction ; the 
 organs of the perceptive faculties are all linked 
 together, as are those of the reflective powers in 
 
203 
 
 like manner ; the organ of artificial language is 
 placed across the organs of the intellectual facul- 
 ties generally. Thus, the especial pains which 
 nature has taken to establish communications be- 
 tween the cerebral parts cannot be overlooked; 
 and, as I have already said, it is this arrangement 
 that enables us to understand the mutual in- 
 fluence of their functions respectively. 
 
204 
 
 Section IX. 
 
 Of the Anatomico- Physiological Relations of the 
 Nervous Apparatuses. 
 
 In Phrenology it is an admitted axiom, that 
 structure does not reveal function ; still, it is cer- 
 tain that there is a relation between the organic 
 structure of an apparatus and its functions. Many 
 considerations bearing upon this point are con- 
 tained in the works which Dr. Gall and I have 
 published conjointly as well as severally. In this 
 place it will be enough merely to refresh the 
 reader’s memory. 
 
 No affective or intellectual function is ever 
 manifested without a brain ; and these functions 
 appear simultaneously with the brain : this organ 
 is in the first instance pulpy, it increases in 
 growth, becomes fibrous, and advances gradually 
 to its maturity ; but after the meridian of life has 
 been passed it shrinks again, and the convolutions 
 become less plump, and seem less firmly packed 
 than in youth and manhood’s prime. The nerves 
 also decrease in old age. The cerebral fibres in 
 declining years acquire density and firmness, but 
 they lose in specific gravity. In conformity with 
 these facts, the mental faculties of newly-born 
 children are confined to voluntary motion, to the 
 
205 
 
 sensation of hunger, and to some obscure feel- 
 ings of pain ; by slow degrees the functions of 
 the external senses become perfect; the child 
 begins to attend to outward objects, to act upon 
 these, to manifest determinate desires and clear 
 notions ; it becomes in succession boy, youth, 
 and man, when the faculties shew themselves 
 in their utmost energy ; little by little they now 
 begin to lose strength, and old age is at length 
 marked by blunted sensibilities, and enfeebled 
 intellectual powers. A defective development 
 of the brain prevents the exhibition of affective 
 and intellectual faculties, and causes idiotism. 
 Men of great and general abilities have always a 
 voluminous brain. Different cerebral parts are dif- 
 ferently developed in the two sexes, in different 
 nations, and in different individuals of the same 
 people. The cerebral organization is oftentimes 
 alike in several of the members of a family. In 
 all these cases it is easy to prove a relation be- 
 tween the condition of the brain and the affective 
 and intellectual manifestations. 
 
 The brains of different species of animals vary 
 in density, in texture, and probably in their ge- 
 neral organic constitution. This is the reason 
 why functions essentially similar offer so many 
 modifications, and never correspond in degree 
 of energy with that of the development of their 
 instruments : that is to say, the affective and in- 
 tellectual aptitudes cannot be measured by the 
 
206 
 
 absolute size of their organic apparatuses. Size, 
 however, is one condition essential to energy ; 
 and other conditions being equal, the largest or- 
 gans will shew the greatest vigour. 
 
 It would appear that, in conformity with the 
 law established in regard to electrical pheno- 
 mena, the energy of nervous apparatuses de- 
 pends in a great measure on their quantity of 
 surface, more on this, perhaps, than on their com- 
 ponent quantity of nervous matter. M. Desmou- 
 lins, in his Memoir to the Academy of Sciences 
 of Paris, attempts to prove, 1st, that integrity of 
 surface is the only constant condition for the pro- 
 duction of nervous actions ; 2nd, that the inten- 
 sity and perfection of nervous actions depend on 
 the proportionate extent of nervous surfaces ; 
 and 3rd, that the nervous actions are performed 
 and transmitted by the surface. 
 
 I do not mean to say that the quantity of a 
 nervous apparatus has no influence on the energy 
 of its functions ; but the influence of the peri- 
 pheral expansion is certainly great. May it be, 
 on this account, that the cerebral apparatuses are 
 hollow or lamellated ? In the inferior classes of 
 animals, the nervous masses are very commonly 
 hollow. 
 
 Cavities and anfractuosities unquestionably in- 
 crease the surface of organs. Have the annular 
 protuberance and corpus callosum of man and the 
 mammalia a like destination ? The cavities and 
 
207 
 
 convolutions also facilitate the circulation of the 
 blood, and thus appear to produce twofold good 
 effects. 
 
 Let us turn, then, and examine the cerebral 
 cavities and their communications. The common 
 number of cavities reckoned is four. The fourth 
 is formed by the separation between the cerebel- 
 lum and medulla oblongata. (PI. ii. fig. 13 ; pi. 
 vii. fig. 2 ; pi. x. fig. 1 ; pi. xi. figs. 1 and 3, m.) 
 The dimensions and development of the fourth 
 ventricle, says M. Desmoulins, coincides with 
 the development of the eighth pair of nerves. 
 Now to me the fourth ventricle seems nothing in 
 itself, and not at all proportionate either to the 
 cerebellum, or the eighth pair of nerves. It, in 
 fact, depends entirely for its size on the united 
 breadth of the medulla oblongata and develop- 
 ment of the cerebellum. Is the cerebellum broad 
 and the medulla oblongata narrow, the fourth 
 ventricle will be narrower than it would have 
 been, were the medulla and cerebellum both 
 broad. In the sturgeon, frog, toad, &c., the 
 fourth ventricle is of considerable magnitude, and 
 the cerebellum very small. 
 
 The fourth ventricle runs between the annular 
 protuberance and valve of Vieussens on to the 
 aqueduct of Sylvius, or canal between the crura of 
 the brain and the commissure of the quadrigeminal 
 bodies. (PI. vii. fig. 2, <p ; pi. x. fig. 1, cp .) This 
 Canal (iter a quarto ad tertium ventriculum ) then 
 
208 
 
 opens into the third cerebral ventricle, or sepa- 
 ration between the great ganglions of the affec- 
 tive faculties. (PI. xi. fig. 1, M.) 
 
 The third ventricle communicates on both 
 sides of the median line by the cleft between 
 the fornix and the great ganglions of the affective 
 powers (pi. x. fig. 1), with the lateral cavities 
 which extend into the anterior, posterior, and 
 middle lobes. 
 
 The communication between the lateral cavi- 
 ties of the brain and the third ventricle is thus 
 established, and not by a natural opening, styled 
 foramen Monroi, nor by any supposed rupture of 
 the septum lucidum. 
 
 Having placed the brain on its superior surface, 
 and cut through the optic nerves, the crura, the 
 annular protuberance, and medulla oblongata at 
 their junction in the median line, and separated 
 the two halves, an opening will be seen between 
 the anterior pillar of the fornix and the great 
 inferior ganglion of the brain. This opening, 
 just described, was called a foramen, by Dr. 
 Monro of Edinburgh, and anatomists have en- 
 titled it foramen Monroianum. It is, as we 
 have seen, no true foramen or hole, but a 
 mere part of the great cleft that brings the third 
 ventricle into communication with the great lateral 
 cavities. 
 
 From this peculiar structure of the cerebral ca- 
 vities, it must appear evident that a great accu- 
 
209 
 
 initiation of water can never be found in one 
 hemisphere only. A small quantity may un- 
 doubtedly be collected in the lateral and poste- 
 rior parts of one of the great ventricles ; but, 
 whenever it becomes considerable, it raises the 
 fornix, flows into the third ventricle, and from 
 this immediately gains the cavity of the oppo- 
 site side. All the observations which have been 
 made are consistent in this particular. The large 
 hydrocephalic crania preserved in museums prove 
 universally that both hemispheres have been dis- 
 tended. 
 
 Some anatomists speak of a fifth ventricle be- 
 tween the two layers of which the septum luci- 
 dum consists ; but in this sense every anfrac- 
 tuosity may be called ventricle. 
 
 M. Serres* is much mistaken when he main- 
 tains that in fishes, reptiles, and birds, there is no 
 , ventricle, and that the brain is a solid mass. In 
 fishes each ganglion is hollow ; and in reptiles 
 and birds there is a cavity between the striated 
 bodies (the great cerebral ganglions) and the 
 fibrous band, precisely as there is one in the 
 mammalia between the two cerebral ganglions, 
 the fornix, and the septum lueidum. (PI. xi. 
 figs. 2 and 3.) 
 
 Here it will not be out of place to take a 
 general and cursory view of what are entitled 
 physiological experiments ; the means which, in 
 
 * Rapport, p. 77, 
 
 P 
 
210 
 
 the eyes of experimenters, ought to establish 
 and confirm the physiology of the nervous sys- 
 tem in general, and of the brain and its parts in 
 particular. Dr. Gall and I have always declared 
 against such violent means of obtaining conclu- 
 sions. We prefer observing the relations be- 
 tween the development of different parts and the 
 exhibition of particular functions, and investi- 
 gating pathological facts. However, I do not 
 incline to neglect any means, whatever its nature ; 
 I conceive that it is a great mistake to confine 
 inquiries within any one particular channel. Mr. 
 Charles Bell regards anatomical research as the 
 means the most favourable to the progress of 
 physiology; Messrs. Magendie, Flourens, and 
 others, on the contrary, prefer physiological ex- 
 periments, in other words, mutilations ; whilst 
 M. Lallemand, again, seems to give the prefer- 
 ence to pathological observations. Pathological 
 cases appear to have been more fertile hitherto in 
 results both anatomically and physiologically, than 
 mutilations. Observing, for example, that the 
 effects of the lesion of one side of the brain 
 were proclaimed on the opposite side of the 
 body, the decussation of the anterior pyramidal 
 bodies was sought for and discovered. Observing 
 that great distention of the cerebral hemispheres 
 did not impede affective and intellectual mani- 
 festations, the structure of the convolutions was 
 inquired into and demonstrated. Remarking that 
 
211 
 
 sensibility may be lost without the powers of 
 motion suffering, and that the power of loco- 
 motion may be lost without that of sensation 
 being disturbed, researches on the nerves of 
 these two sorts of functions have been instituted, 
 and so on. Pathological facts, however, cannot 
 be interpreted in opposition to physiological ob- 
 servations. Will any one say with M. Foville, 
 that the superficial substance of the brain pre- 
 sides over the intellectual functions, and the 
 white and deep-seated masses of gray substance 
 over locomotion, because he has observed that 
 derangements of these two orders of functions 
 accompanied organic alterations of the superfices, 
 or internal parts of the brain? Will any one say 
 again, with Messrs. Foville and Serres, that the 
 great ganglion of the affective faculties (thalamus) 
 and its white fibres are in relation to the motion 
 of the arm and the ganglion of the intellectual 
 faculties (corpus striatum) and its radiating fibres 
 to the motion of the leg? Is it not necessary, 
 before such a proposition be received as correct, 
 to prove physiological observations in harmony 
 with these pathological cases ? This, however, 
 has not and cannot be done : hence there cannot 
 possibly be any truth in the above surmises. 
 
 Physiological experiments would tend to the 
 establishment of yet more extraordinary ideas. 
 M. Magendie pretends, that without the trige- 
 minal nerve (fifth pair), we could neither hear, 
 
 P 2 
 
212 
 
 nor see, nor smell ; that the cerebellum is neces- 
 sary to precision in all movements forward, as 
 every severe wound of the cerebellum renders 
 motion in this direction impossible ; that the 
 crura of the brain, the quadrigeminal tubercles, 
 the pretended thalami, and the striated bodies, 
 have all functions relative to motion ; lastly, that, 
 the nerves arising from the posterior roots of the 
 spinal cord belong to sensation, and those of the 
 anterior roots to motion, whilst M. Bellingeri * 
 says, that his experiments lead him to conclude 
 that the function of the posterior roots is motion, 
 especially motion of extension, and not sensa- 
 tion. He thought he could confidently advance, 
 that when feeling only was paralyzed, the seat of 
 the disorder was in the cineritious substance ; 
 that in palsy of the locomotive powers without 
 loss of feeling, the disease was exclusively in 
 the white substance ; and that in palsy of both 
 functions the two substances were altered at the 
 place where the nerves distributed to the affected 
 parts arise. In fine, if the loss of motion be a 
 more frequent symptom than the loss of feeling, 
 this, according to our author, happens from the 
 white substance being situated on the outside of 
 the spinal cord, and consequently, in his esti- 
 mation, being more exposed than the gray to the 
 action of external agents. 
 
 The cerebellum, by the experiments of M. 
 
 * Mem. dell’ Academia delle Scienze di Torino, tom. 30. 
 
213 
 
 Rolando, is made out an electrometer, or sort of 
 voltaic pile, and the sole source of a fluid that 
 excites motion; whilst M. Flourens, by his expe- 
 riments discovers that the cerebellum is the 
 balancer, or governor, or regulator of voluntary 
 motion. 
 
 In the opinion of some experimenters, the qua- 
 drigeminal tubercles are the seat of vision ; but 
 M. Flourens is led to consider them as the simple 
 conductors of vision, which is not changed into 
 perception but in the brain itself, because he 
 found that on cutting away a lobe, he produced 
 blindness of the opposite eye. 
 
 The medulla oblongata, according to M. Flou- 
 rens, is the central magazine, the vital knot of 
 the nervous system, to which all impressions 
 must come, to be appreciated ; from which the 
 commands of the will must emanate, to be exe- 
 cuted ; to which it is sufficient for parts to be 
 attached, in order to live, and from which to be 
 detached, is sufficient cause of death. But M. 
 Fodera, from his experiments, believes that the 
 medulla oblongata is the seat of dozing and of 
 sleep ; he even accords to this part of the ence- 
 phalon, some influence on the production of moral 
 phenomena. 
 
 Lastly, according to M. Flourens, the brain 
 includes sensibility and will ; without brain, no 
 sensation, no will. M. Rolando observed that 
 dozing and stupidity supervened each time he 
 
214 
 
 cut away the cerebral lobes. He conceives the 
 brain to be, at once, the seat of the sensitive and 
 intellectual faculties, and the agent of the cere- 
 bellum’s regulating and directing power on the 
 motions, an agent, however, which cannot influ- 
 ence the motions without the cerebellum, their 
 immediate cause. 
 
 The reader must have felt the jarring and 
 contradictory nature, and insufficiency of the pre- 
 ceding opinions. They do not appear to me 
 worthy of any detailed refutation. Their con- 
 tradictions bespeak clearly enough their falsity. 
 I do not deny the facts, as they are reported by 
 the experimenters, but I think these gentlemen 
 over-eager and too ready to draw conclusions : I 
 see them unapt to distinguish between facts and 
 their causes, between primary and secondary 
 causes, and to separate powers and conditions to 
 activity from actions. I also think that they ne- 
 glect the mutual influence of the several instru- 
 ments too much ; and that they frequently attri- 
 bute to one condition, that which belongs to seve- 
 ral. The trigeminal nerve aids the nerve of vision, 
 but the optic nerve is the instrument of sight ; 
 the olfactory nerve is assisted in its office by the 
 nerves of inspiration, of the nostrils, but it alone 
 procures the special sensation we entitle smell. 
 
 These physiological experiments or mutilations, 
 would reduce the functions of the spino-cerebral 
 system to a very small compass ; and it is but 
 
215 
 
 natural that I should declare for the physiological 
 observations made in the state of health, by con- 
 sidering the relation between the development of 
 special organs, and the energy of peculiar mani- 
 festations. These observations are collected, and 
 their results proclaimed in the volume entitled 
 Phrenology. 
 
 I conclude this treatise by repeating, that the 
 anatomical knowledge of the nervous system in 
 general, and of the brain in particular, must be 
 in harmony with physiology and pathology ; and 
 that any one of these three departments must be 
 modified whenever there is contradiction in refer- 
 ence to any of the others. 
 
216 
 
 EXPLANATION 
 
 OF 
 
 THE PLATES AND FIGURES. 
 
 Plate I. 
 
 Fig. 1. Four ganglions, with their branches of commu- 
 nication, of the caudal extremity of a caterpillar. This 
 arrangement of the nervous system reigns through the 
 entire length of the body of caterpillars and worms. 
 
 Fig. 2. The caudal extremity of the spinal marrow of 
 a fowl, with the origin of the three last pairs of dorsal 
 nerves. 
 
 Fig. 3. The three superior cervical pairs of nerves in a 
 calf, seen on the abdominal surface. The dura mater and 
 arachnoid are slit longitudinally and turned aside, so as 
 to expose the mode in which the nervous filaments come 
 from the common mass, their different directions, and the 
 passage of the bundles through the dura mater. The com- 
 mencement of the intervertebral ganglions (a) is covered 
 by the reflected membranes. Between the different pairs 
 of nerves, the teeth of the ligamentum dentatum ( b ) are 
 Been on each side of the nervous mass ; these ligaments 
 separate the abdominal from the dorsal roots, and are 
 attached to the dura mater by means of slips, naturally 
 different in size and position. At the origin of each pair 
 of nerves, a swelling is perceivable, varying in magnitude, 
 in proportion to the volume of the issuing nerve. The 
 
direction of the nervous fibres from before backwards, and 
 from behind forwards, is evident. 
 
 2, 3. The accessory nerve. 
 
 5. Median abdominal fissure. 
 
 Fig. 4. The four superior cervical pairs f nerves in man, 
 seen from before. 
 
 Fig. 5. The five superior cervical pairs of nerves in man, 
 seen from behind. 
 
 The membranes, ligamentum dentatum, accessory nerve, 
 intervertebral ganglions, bulgings and contractions of the 
 nervous mass, are, absolutely, the same as in Fig. 3. On the 
 dorsal surface there are, frequently, fibres of communica- 
 tion from one pair of nerves to the other, for instance, 
 between the fourth and fifth pairs. 
 
 Fig. 4. 5 — 5. Median abdominal fissure. 
 
 Fig. 5. 5 — 5. Median dorsal fissure. 
 
 a — x. Lateral dorsal channels. 
 
 Fig. 6. The edges of the two abdominal halves sepa- 
 rated, permitting a view of the structure at the bottom of 
 the abdominal fissure. 
 
 /3 — /3. Lateral cords. 
 
 3- — 3. Apparatus of union of the two halves situated at 
 the bottom of the abdominal fissure. 
 
 Fig. 7. The edges of the two dorsal halves, separated, 
 permitting a view of the structure at the bottom of the 
 dorsal fissure. 
 
 j2 — /3. Lateral edges . 
 
 — 9-. Apparatus of union of the two halves situated at 
 the bottom of the dorsal fissure. 
 
 Fig. 8. Transverse section of the cervical nervous mass 
 of a carp. 
 
 Fig. 9. Transverse section of the cervical nervous mass 
 of a fowl. 
 
218 
 
 Fig. 10. Transverse section of the cervical nervous mass 
 of a man. 
 
 In the three last figui-es, the general type is the same : 
 two halves of the spinal cord ; two median fissures, an 
 anterior and a posterior. 
 
 S. Exit of the abdominal roots of the nerves. 
 
 y. Exit of the dorsal roots of the nerves. 
 
 Plate II. — Brains of Fishes. 
 
 Fig. 1 . The brain of an eel seen from above. 
 
 Fig. 2. The brain of a cod seen from above. 
 
 Fig. 3. The brain of a skate seen from above. 
 
 Fig. 4. The brain of a carp seen from below. 
 
 Fig. 5. The brain of a carp seen from above. 
 
 Fig. 6. The brain of a flounder seen from below. 
 
 Fig. 7. The brain of a flounder seen from above. 
 
 Fig. 8. The brain of a cod seen from below. 
 
 Fig. 9. The optic nerves in the cod are thrown back, to 
 permit a view of the two roots of the olfactory nerves. 
 
 Fig. 10. The brain of a pike, with the cavity of the 
 optic ganglion exposed. 
 
 Fig. 11. The brain of a roach. 
 
 Fig. 12. The brain of a barbel seen from above. 
 
 Fig. 13. The interior of the brain of a barbel, prepared 
 to permit a view of the ganglions, their communications, 
 and junctions. 
 
 Plate III. — Brains of Reptiles and of Birds. 
 
 Fig. 1. The spino-cerebral system of a frog seen from 
 below. 
 
 Fig. 2. The brain of a frog seen from above. 
 
 Fig. 3. From M. Carus’s work. — The brain of a lizard 
 (lacerta iguana) seen from above. 
 
219 
 
 Fig. 4. From M. Carus’s work. — The brain of a young 
 crocodile seen from above. 
 
 Fig. 5. The brain of a common fowl seen from above. 
 
 Fig. 6. The brain of a fowl. — The two hemispheres 
 separated to shew the cerebellum, the optic ganglions, 
 their commissure, the commencement of the supposed optic 
 thalami, and the part analogous to the fornix of the 
 mammalia. 
 
 Fig. 7. The brain of a turkey seen from above. 
 
 Fig. 8. The brain of a turkey with the cerebellum cleft 
 posteriorly, to shew its lamellar structure. 
 
 Fig. 9. The brain of a common fowl, prepared to shew 
 the cavity of the optic ganglion, the posterior commissure, 
 v. ; the beginning and continuation of the great cerebral 
 ganglions. 
 
 Fig. 10. The brain of a duck seen from above. 
 
 Fig. 11. The brain of a goose seen from above. 
 
 Fig. 12. The bx - ain of a goose seen from below. 
 
 Plate IV. — Brains of Mammiferous Animals. 
 
 Fig. 1. The brain of myrmesophaga didactyla seen from 
 above, copied from the work of Tiedemann. 
 
 Fig. 2. The brain of a hare seen from below. 
 
 Fig. 3. The brain of a hare seen from above. 
 
 Fig. 4. The brain of a hare placed on its upper surface, 
 like Fig 2 ; the mass below the crura cerebri is cut olf ; the 
 crura are separated and pushed sidewards, to see the under 
 surface of the posterior lobes ; the fornix, 60 ; the posterior 
 fold of the corpus callosum, 40; the anterior pillar of 
 the fornix y; the anterior commissure, 61, and its two 
 portions. 
 
 Fig. 5. The brain of a cat seen from above, 
 
220 
 
 Fig. 6. The brain of a dog seen from above. All parts 
 are reduced to the fourth of their natural size. 
 
 Plate Y. 
 
 [The brains and their parts, represented in this plate, and all 
 preparations of the human brain, in the following plates, 
 are only a fourth of their natural size.] 
 
 Fig. 1. The brain of the monkey, simia sabcea, seen 
 from above. 
 
 Fig. 2. The brain of the monkey, simia capucina, seen 
 from above. 
 
 Fig. 3. The brain of the ourang-outang seen from below. 
 
 Fig. 4. The brain of the ourang-outang seen from the 
 right side. 
 
 Fig. 5. The brain of an idiotic girl seen from below. 
 
 Fig. 6. The same brain of the idiotic girl seen from the 
 right side. 
 
 Plate VI. 
 
 Fig. 1. The basis of the human brain. — All the parts 
 are in pairs, but not quite symmetrical. The brain is taken 
 from the skull, and turned on its upper surface; the cere- 
 bellum and medulla oblongata have fallen backwards ; the 
 different investing membranes are removed ; the cerebral 
 and nervous masses alone are visible. 
 
 To take the human brain from the skull, I make an in- 
 cision from one ear to the other, turn the integuments 
 backwards and forwards, and detach the temporal muscles 
 from the bone. If it is requisite to preserve the skull, 
 it must be sawed about three-quarters of an inch above 
 the superciliary ridge, round on each side to the middle of 
 the occipital bone ; if it be no object to keep the skull 
 
221 
 
 entire, Bichat's plan, which is much easier and more 
 speedily accomplished, may be followed ; it consists in 
 using the sharp edge of a hammer along the course indi- 
 cated, and breaking instead of sawing the skull. In this 
 way infinitely less risk is run of injuring the membranes 
 and cerebral convolutions than when the saw is employed. 
 There then usually issues a greater quantity of fluid 
 from between the membranes, and from out of the vessels 
 of the neck when they are divided, in consequence of the 
 shaking the parts have undergone ; the cerebral mass also 
 sinks to a greater extent, and the dura mater does not 
 look so tightly stretched over the convolutions, but the 
 internal organization suffers no change. 
 
 When the skull-cap is removed, I cut the dura mater 
 on each side of the longitudinal sinus before and behind, 
 and transversely between the ears ; I then turn down the 
 flaps, detaching the falciform process of the dura mater 
 in the frontal region, and turn it backwards. I now bring 
 back the head, so that the base becomes the superior part ; 
 I support it with the left hand in the occipital region, and 
 the brain then lies on the palm of the hand. Their own 
 weight almost always suffices to detach the anterior and 
 middle lobes from their places, — at the most, the slightest 
 assistance from the fingers accomplishes this. The bulb 
 of the olfactory nerve generally separates from the eth- 
 moid bone of itself, or the handle of the scalpel detaches 
 it with ease. The optic nerves, the infundibulum, the 
 oculo-motors, the abductor nerves of the eye, the nerves 
 of the superior oblique, and the trigeminal pair, must be 
 cut in succession ; I now depress the head upon the hand, 
 first on one, then on the other side, pushing at each time 
 the hemispheres from the tentorium, in order to cut this 
 part across. After this, I detach the nervous pairs and 
 
222 
 
 blood-vessels situated near the medulla oblongata; and, 
 lastly, I cut the cervical nervous mass below the occi- 
 pital hole, as low down as possible, not to damage the 
 decussating fibi’es. I raise the cerebellum with the fingers 
 of the right hand, and lift the entire cerebral mass from 
 the cranium. There is one precaution that is very neces- 
 sary to be taken, it is, to support the hemispheres with 
 the flat of the hand properly, to prevent the crura from 
 being torn before the tentorium is cut, and to guard 
 against the same accident, in regard to the medulla oblon- 
 gata below the annular protuberance. 
 
 A hammer or a saw, and two scalpels, the one to sepa- 
 rate the integuments and the muscles, the cither to cut the 
 membranes and the nervous parts suffice for this operation. 
 It is well to have the second scalpel long in the handle, to 
 secure the cervical nervous mass beiug easily divided low 
 enough down. 
 
 Fig. 2. A skull sawed vertically through the middle of 
 the forehead, the vertex and the occiput, to expose the 
 exterior and lateral surface of the brain, cerebellum, an- 
 nular protuberance, and medulla oblongata in their natu- 
 ral situations. The bone here supports the cerebellum 
 and medulla oblongata, whilst in Fig. 1 they had sunk 
 downwards and backwards. 
 
 Plate YII. 
 
 Fig. 1 . A skull sawed horizontally in a line from above 
 the eye-brows, by the middle of the temples, and the 
 upper part of the occipital bone. The membranes and 
 blood-vessels are removed, and the two hemispheres are 
 seen from above. 
 
 Fig. 2. The skull, brain, and cerebellum cut vertically 
 
223 
 
 through the median line, and in their natural situations. 
 In this preparation the various parts are retained in their 
 proper places, not without considerable difficulty. 
 
 Plate YIII. 
 
 Fig. 1. A preparation exhibiting various parts about 
 the base of the brain. 
 
 Side B. The hemisphere of the cerebellum entire ; its 
 primary bundle is seen to plunge between the facial nerve, 
 11, and the auditory nerve, 9. The trigeminal nerve, 12, 
 is entirely covered by the transverse fibres of the cerebel- 
 lum; the olivary body, a, plunges through the transverse 
 fibres of the cerebellum ; a portion of the transverse mass 
 is removed to exhibit the course of the pyramidal bundle, 
 1 — c, which begins to diverge and to be augmented. The 
 optic nerve is in its natural position ; on its outer edge the 
 expansion of the nervous bundles, W, W, W, in the in- 
 ferior convolutions of the middle lobe, is seen. 
 
 Side A. A vertical section of the cerebellum guided 
 through the entrance of its primary bundle, and the mid- 
 dle of its ganglion, s, shewing the augmentation of the 
 primary bundle in the ganglion, and the ramifications and 
 subdivisions of the nervous cords. All the transverse 
 fibres of the annular protuberance, which cover the tri- 
 geminal nerve, and the prolongation of the pyramidal bun- 
 dle, are cut away. The continuation of the olivary body, 
 a, is still covered by the transverse bundles. The optic 
 nerve is raised from the crura, g, and cut across at q. 
 The pyramidal bundle is thus exposed from the decus- 
 sation, 1, to the transverse interlacement beneath the 
 optic nerve. The mass of gray substance seen on the op- 
 posite side has been scraped off, in order to expose the 
 
224 
 
 two cords of the mammillary bodies, 16, the one near 
 the transverse interlacement, 35, the other towards the 
 fornix. The nervous fibres that expand in the convo- 
 lutions, and contribute to their formation, are cut at h, h, 
 between 35 and 37, on a level with the anterior commis- 
 sure, and the middle lobe is removed altogether. The 
 mass of gray substance of the great superior cerebral gan- 
 glion (striated body), and a part of the convolutions lying 
 at the bottom of the great fissure, D, between the anterior 
 and middle lobes, are incised in the same direction The 
 way in which this collection of gray substance is divided 
 by the nervous bundles, P, at its internal, l, and its ex- 
 ternal, L, parts, the mode in which fine filaments tra- 
 verse the external part of the gray mass, the manner in 
 which the convolutions, 44 — 45, are formed by the pos- 
 terior cords of the cerebral crura placed before q, and 
 the length and the depth of the great fissure, between 
 the anterior and middle lobes, are all exposed in this pre- 
 paration. By the removal of the middle lobe, the side 
 of the great lateral ventricle, N, has become visible. 
 This ventricle is continued backwards, inwards, and for- 
 wards, below the crura of the brain, g. Only a small 
 portion of the anterior lobe is cut off. 
 
 Fig. 2. The great commissure of the cerebellum (annu- 
 lar protuberance), b; the anterior commissure, and the 
 commissure of the anterior lobe (the anterior fold of the 
 corpus callosum), 39, are here represented. 
 
 Side A. The anterior edge of the cerebellum is removed 
 by a vertical cut from within outwards, to expose the 
 conveyance of the uniting fibres towards the median line ; 
 the middle and anterior lobes of the brain are entire ; the 
 optic nerve is turned back, to exhibit the augmentation it 
 has received from the gray mass situated at its junction. 
 
225 
 
 The communication of the white fibres, 63, before the optic 
 nerve, and in front of the anterior commissure, 61, toge- 
 ther with the septum lucidum, and the connexion of the 
 olfactory nerve with the inferior convolutions of the an- 
 terior lobe, are also to be seen. 
 
 Side B. The lower portion of the cerebellum is re- 
 moved by a horizontal incision, 65, which passes by the deep 
 channel seen on side A. 
 
 To shew the anterior commissure, I cut the optic nerves 
 at their junction, reflect their two extremities, and from 
 the middle of the commissure I begin with the handle of 
 the knife to remove all the parts that cover it, taking care 
 to injure none of the fibres of the commissure itself. One 
 part of the convolutions, the interior of which is called 
 foot of the hippocampus, 29, and the anterior internal con- 
 volutions of the middle lobes, are cut off. 
 
 The brain has been left in the cranium, but as this has 
 been cut away above the cerebellum, and a part of the pos- 
 terior cerebral lobes, these masses have fallen out of their 
 natural situations ; and on the side B, the convolutions of 
 the middle lobe have been pushed outwards, because the 
 commissure was prepared from within outwards. 
 
 Plate IX. 
 
 Fig. 1. The cranium sawed on the right side; the cut 
 passes vertically by the middle of the cerebral and cere- 
 bellar hemispheres, and by the right orbit. The great 
 union of the cerebellum, b, is cut transversely behind the 
 exit of the trigeminal nerve, and the external part of the 
 cerebellum is removed. The cerebral parts which, in 
 pi. viii. fig. 1, were situated between the transverse inter- 
 lacement, 35, and the nervous bundles, P, are taken 
 
 Q 
 
226 
 
 away, so as to jjermit a view of the divergeance of the 
 fibres in all directions. 
 
 By comparing this figure with the first figure of pi. 
 viii. the different appearances of the same parts prepared 
 in their situations, with the support of the cranium, and 
 deprived of this by being taken out of the skull, will be 
 appreciated. 
 
 Fig. 2. The cranium sawed perpendicularly in the 
 middle line of the head. All the parts which are seen in 
 pi. vii. fig. 2, even to the convolutions, indicated by Ro- 
 man letters, are here removed by cutting or scraping, in 
 order to shew the passage of the pyramidal bodies, 1 — c, 
 across the annular protuberance, f, the augmentation of 
 the diverging bundles in the great inferior ganglion (optic 
 thalamus) p, and the course of the bundles which issue 
 from them. 
 
 The course of the bundles, which communicate directly 
 with the anterior pyramids, is principally shewn in fig. 1 ; 
 whilst the manner in which the internal and posterior 
 convolutions of the hemispheres are formed by the ner- 
 vous fibres of the great inferior ganglion of the brain, 
 (thalamus opticus,) is seen in fig. 2. 
 
 Plate X. 
 
 Fig. l.The brain laid on its superior surface. The side 
 B, exhibits the entire nervous mass of the brain and 
 cerebellum, cleft in the median line from the medulla ob- 
 longata to the fornix, and laid on the side. The gray mass 
 behind the junction of the optic nerves, and a small part 
 of the pretended thalami have been scraped away, to 
 expose the two internal cords of the mammillary bo- 
 dies, 16, the one running towards the transparent septum, 
 
227 
 
 57, 58, 59, the other plunging into the interior of the 
 great inferior ganglion, p, p. Side A. The medulla ob- 
 longata and cerebellum are cut near the annular protu- 
 berance. At 30, a part of the median layer is removed, 
 to expose the continuation of the oculo-motor nerve into 
 the black substance. The posterior part of the great in- 
 ferior ganglion, the half of the pineal gland with two 
 cords, and the quadrigeminal bodies, are as on the opposite 
 side B ; the anterior part of the great inferior ganglion is 
 cut on, to shew the prolongation of the internal posterior 
 cord of the mammillary bodies, with the transverse inter- 
 lacement 36, pi. viii. ; the septum lucidum, the fornix, the 
 internal portion of gray substance of the corpus striatum, 
 and several internal convolutions of the posterior and mid- 
 dle lobes, are removed, to shew the great diverging bundles 
 P, P, and the masses of union, known by the name of 
 corpus callosum, in the great cerebral cavities N, N. The 
 anterior 39, and the posterior 40, fold; and the raphe of 
 this mass are perceived. The direction of the converging 
 fibres from behind is forwards and inwards, from before 
 backwards and inwards, and from the middle directly in- 
 wards. Lastly, the interlacing of the diverging bundles 
 with the fibres of union is presented. 
 
 Fig. 2. The brain of a goose laid on its upper surface. 
 Side B. The cerebellum and the hemisphere of the brain 
 entire ; the medulla oblongata cleft along the median line, 
 and one of its halves put aside. 
 
 Side A. The half of the medulla oblongata, its adhe- 
 rence to the cerebellum, and its continuation towards the 
 brain at the crus are divided, to expose the communication 
 between the cerebellum and the optic ganglion, which 
 is hollow, and communicates from its anterior by means 
 of a white layer with the brain. 
 
 Q 2 
 
228 
 
 Fig. 3. The brain of a goose laid on its superior sur- 
 face. Side B. The half of the brain and medulla ob- 
 longata, as in B, fig. 2 ; but the inferior and posterior 
 part of the cerebellum is here cleft, to exhibit its lamellar 
 structure. The optic ganglion and the optic nerve are 
 taken away to show the continuation of the anterior com- 
 missure, 61, and the entrance of the crus, p, into the 
 hemisphere. 
 
 Plate XI. 
 
 Fig. 1. The human brain laid on its base ; the primary 
 part of the cerebellum and the corpus callosum are split 
 along the median line. The posterior surface of the me- 
 dulla oblongata, the posterior pyramidal bodies, the pri- 
 mary bundles of the cerebellum, and a third portion of 
 the restiform bodies, e — e ; the interior of the fourth 
 ventricle, m, the communication of the cerebellum, y, with 
 the quadrigeminal bodies, n, o, and their union, x, the ori- 
 gin of the sympathetic nerve, 13, the pineal gland E, with 
 its two anterior cords ; the posterior commissure, v, the 
 soft commissure, 46, and the anterior commissure, 61, 
 cleft. On the side A, only the fornix and the septum lu- 
 cidum are removed, to expose the striated bodies and tha- 
 lami lying beneath. Side B. The primary bundle of the 
 cerebellum and the parts, seen on the surface of side A, 
 have been removed by a horizontal cut from within out- 
 wards, and from before backwards, on a level with the 
 white fibres situated in the fourth ventricle, t. The internal 
 portion of the anterior part of the brain has also been 
 cut away by a vertical incision, in order to expose the di- 
 vision of the striated bodies into two parts, /, L, by the 
 passage of the great bundles P. 
 
229 
 
 This vertical cut is not made to begin more posteriorly, 
 for fear of injuring the commissures visible along the me- 
 dian line. To exhibit the passage of the bundles from 
 the medulla oblongata across the great ganglions, and the 
 augmentation of the parts, the cut must be carried, pi. 
 vi. fig. 1, through the middle of the anterior pyramidal 
 bodies, 1 — c, through the annular protuberance, b, the 
 crura of the brain, g, in the direction of the organ IX. 
 
 Fig. 2 and 3. The brains of geese laid on their inferior 
 surfaces. Fig. 3. Side B. The hemisphere of the brain 
 put aside, and the cerebellum cleft along the median line, 
 to shew its lamellar structure and internal cavity, 62. Side 
 A. The optic ganglion exposed, n ; a part of the crus and 
 anterior internal portion of the brain to the junction 
 of the optic nerves removed ; part of the crus and of the 
 striated bodies seen interiorly remaining. 
 
 Fig. 2. The cerebellum cleft along its inferior surface, 
 and spread out on each side ; the pretended optic thalami 
 on both sides, n, and the striated bodies, l, l, on side A, are 
 in the natural state ; whilst on side B the radiated layer of 
 cerebral substance is visible anteriorly, P ; the anterior 
 commissure, 61, is perceived in its full length. The pos- 
 terior portion of the hemisphere, 60, untouched. 
 
 Explanation of the Signs in the Figures. 
 
 A and B. Sides of preparation. 
 
 D. Convolutions at the bottom of the figure of Sylvius. 
 
 E. Pineal gland. 
 
 L. External portion of the great superior ganglion, 
 (striated body.) 
 
230 
 
 M. Third ventricle. 
 
 N. Great lateral ventricles. 
 
 P. The bundles of the striated bodies. 
 
 a. Olivary bodies. 
 
 b. Annular protuberance. 
 
 c. Entrance of the anterior pyramids under the annular 
 protuberance. 
 
 d. Transverse band below the pons Varolii in mammi- 
 ferous animals. 
 
 e. Restiform bodies. 
 
 f. Passage of the anterior pyramids through the annu- 
 lar protuberance. 
 
 g. Peduncles of the brain. 
 
 h. Section of the bundles which go to the middle lobe. 
 
 i. Origin of the trigeminal nerve. 
 k. Exit of the trigeminal nerve. 
 
 I- Intei’nal part of the great superior ganglion (striated 
 body). 
 
 m. Fourth ventricle. 
 
 n. Anterior pair of the quadrigeminal bodies. 
 
 o. Posterior pair of the quadrigeminal bodies. 
 
 p. Great inferior ganglion (thalamus). 
 
 q. Corpus geniculatum externum. 
 
 r. Corpus geniculatum internum. 
 
 s. Ganglion of the cerebellum (corpus dentatum). 
 
 t. White fibres in the fourth ventricle. 
 
 u. Junction of the optic nerves. 
 
 v. Posterior commissure. 
 
 w. Fibres in communication with the external edge of 
 the optic nerve. 
 
 x. Commissure of the quadrigeminal bodies. 
 
 y. Valve of Vieussenius. 
 
 Lateval fissure of the spinal cord. 
 
231 
 
 /3. Mesial edge of the spinal cord. 
 y. Anterior pillar of the fornix. 
 
 &. Abdominal root of the spinal nerves. 
 q. Dorsal root of the spinal nerves. 
 
 3-. Commissure of the spinal cord. 
 
 X. Extremity of the corpus callosum. 
 
 1 *. Middle part of the corpus callosum. 
 
 <p. Aqueduct of Sylvius. 
 
 I. Decussation of the anterior pyramids. 
 
 2 — 3. Accessory nerve. 
 
 4. Hypoglossal nerve. 
 
 5. Mesial fissure of the spinal cord. 
 
 6. Pneumogastrical nerve. 
 
 7. Glossopharyngeal nerve. 
 
 8. Ganglion of the auditory nerve. 
 
 9. Auditory nerve. 
 
 10. Abductor nerve. 
 
 II. Facial nerve. 
 
 12. Trigeminal nerve. 
 
 13. Superior oblique nerve. 
 
 14. Section of the annular protuberance. 
 
 15. Common oculo-motor nerve. 
 
 16. Mammillary body. 
 
 17. Cineritious tubercle. 
 
 18. External root of the olfactory nerve. 
 
 19. Middle root of the olfactory nerve. 
 
 20. Optic nerve. 
 
 21. Internal root of the olfactory nerve. 
 
 22. Infundibulum. 
 
 23. Bulb or ganglion of the olfactory nerve 
 
 25 — 26. Anterior lobe of the brain. 
 
 26— 27. Middle lobe of the brain. 
 
 27 — 28. Posterior lobe of the brain. 
 
232 
 
 29. Convolutions, which, viewed from within, form the 
 pes hippocampi. 
 
 30. Black substance in the peduncles of the brain. 
 
 31. Commissure of the olfactory nerve in animals. 
 
 32. Semicircular band or tape-worm of Haller. 
 
 33. Transverse band at the upper edge of the annular 
 protuberance. 
 
 34. Transverse band in the midst of the peduncles. 
 
 35. Transverse band under the optic nerve. 
 
 36. Transverse band of the bundles which go to the 
 middle lobe. 
 
 37. Transverse band of the great superior ganglion. 
 
 38. Place where the diverging and uniting fibres de- 
 cussate. 
 
 39. Anterior fold of the corpus callosum. 
 
 40. Posterior fold of the corpus callosum. 
 
 41. Upper surface of the primary part of the cere- 
 bellum. 
 
 42. Inferior surface of the primary part of the cere- 
 bellum. 
 
 43. Tubercle of the fourth ventricle in fishes. 
 
 44 — 45. Cerebral convolutions behind the great fissure 
 of Sylvius. 
 
 46. Soft or middle commissure. 
 
 47 — 48. Situation of the organ of amativeness. 
 
 48 — 49. Situation of the organ of inhabitiveness. 
 
 50 — 51. Situation of the organ of self-esteem. 
 
 51 — 52. Situation of the organ of firmness. 
 
 52 — 53. Situation of the organ of veneration. 
 
 53 — 54. Situation of the organ of benevolence. 
 
 54 — 55. Situation of the organ of comparison. 
 
 55 — 56. Situation of the organ of eventuality. 
 
 57, 58, and 59. Septum lucidum. 
 
233 
 
 60. Fornix. 
 
 61. Anterior commissure. 
 
 62. Interior of the nervous substance of the cerebellum. 
 
 63. White fibres, which unite with the septum lucidum. 
 65. Horizontal section of the cerebellum. 
 
 70. Nervous bundles of the organs of the affective 
 faculties. 
 
 86, 87, 88, 90. Intermedial layers of fibres between the 
 two halves of the cerebral masses. 
 
 \ 
 
 i. Organ 
 
 of Amativeness. 
 
 ii. 
 
 . Philoprogenitiveness. 
 
 hi. . 
 
 . Inhabitiveness. 
 
 IV. 
 
 . Adhesiveness. 
 
 V. 
 
 . Combativeness. 
 
 VI. 
 
 . Destructiveness. 
 
 VII. . 
 
 . Secretiveness. 
 
 VIII. . 
 
 . Acquisitiveness. 
 
 IX. 
 
 . Constructiveness. 
 
 X. 
 
 Self-esteem. 
 
 XI. . 
 
 . Love of approbation 
 
 XII. . 
 
 . Cautiousness. 
 
 XIII. 
 
 Benevolence. 
 
 XIV. . 
 
 . V eneration . 
 
 XV. . 
 
 . Firmness. 
 
 XVI. . 
 
 . Conscientiousness. 
 
 XVII. 
 
 . Hope. 
 
 XVIII. 
 
 . Marvellousness. 
 
 XIX. 
 
 . Ideality. 
 
 XX. . 
 
 . Mirthfulness. 
 
 XXI. . 
 
 . Imitation, 
 
xxii. Organ 
 
 of Individuality. 
 
 XXIII. . . 
 
 Configuration. 
 
 XXIV. . . 
 
 Size. 
 
 XXV. . . 
 
 Weight and resistance. 
 
 XXVI. * . 
 
 Colouring. 
 
 XXVII. . . 
 
 Locality. 
 
 XXVIII. . . 
 
 Calculation . 
 
 XXIX. . . 
 
 Order. 
 
 XXX. . . 
 
 Eventual ity. 
 
 XXXI. . . 
 
 Time. 
 
 XXXII. . 
 
 Melody. 
 
 XXXIII. . . 
 
 Language. 
 
 XXXIV. . . 
 
 Comparison. 
 
 XXXV. . 
 
 Causality. 
 
 THE END. 
 
PL . I. 
 
 Fia.S. 
 
 Published ty D^Sp urskeini 189.6 
 

 
 
 
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