722s 



PHYSIOLOGY OF THE NERVOUS SYSTEM. 



all the anatomical conditions necessary for 

 the developement of acts of sensation and 

 volition. 



It thus appears that Flourens' views re- 

 specting the office of the cerebellum derive 

 considerable support both from experiment and 

 from anatomy. When we come to collect the 

 evidence on this subject which has been fur- 

 nished by the effects of disease, we obtain very 

 little information of a satisfactory kind. A 

 superficial lesion of either cerebellar hemi- 

 sphere or of the median lobe does not cause 

 paralysis, but may produce delirium or con- 

 vulsions, as a superficial lesion of either ce- 

 rebral hemisphere may; but a deep-seated 

 lesion of the cerebellum involving the central 

 white substance which is continued from the 

 cms cerebelli causes hemiplegia on the oppo- 

 site side. This similarity between the effects 

 of cerebellar and of cerebral disease is a re- 

 markable and highly interesting fact, but one 

 which considerably increases the difficulty of 

 obtaining from pathological phenomena any 

 contribution to the solution of physiological 

 questions. It may be explained thus : the 

 transverse fibres of the pons passing through the 

 mesocephale would propagate to this segment 

 the morbid influence of any deep-seated lesion 

 of the cerebellum, and thus affect the adjacent 

 pyramid, which again would affect the opposite 

 half of the body just as if the morbid influence 

 originated in the cerebral hemisphere. It is, 

 then, this secondary affection of either pyra- 

 midal body which obscures the proper signs 

 referable to cerebellar lesion. 



A few cases, however, have been put on re- 

 cord, in which a tottering gait, like that of a 

 drunken man, and a defective power of co- 

 ordination existed in connection with a diseased 

 state of cerebellum. A striking instance of 

 this occurred under my own observation: a 

 young surgeon, who had recently received an 

 appointment in the medical service of the 

 army, was in attendance in the military hos- 

 pitals at Chatham, preparatory to his nomina- 

 tion to a regiment. It was observed that as 

 he walked he staggered to so great a degree 

 that he was suspected of drinking to excess, 

 and was put under arrest on this account. 

 It was soon, however, found that he was suffer- 

 ing under symptoms of diseased brain, and 

 he was sent up to town and placed under my 

 care. I found that his principal symptom was 

 extreme difficulty in the coordination of his 

 movements, accompanied by a sense of gid- 

 diness in the head. He could neither stand 

 nor walk, yet there was no distinct paralysis, 

 for while he was in the recumbent posture he 

 could move about his limbs freely. After a 

 time he became amaurotic and comatose. The 

 post-mortem examination revealed softening of 

 the left crus cerebri and a patch of yellow soft- 

 ening on the corresponding restiform body : 

 there was in addition a recent deposit of lymph 

 at the base of the brain around the optic com- 

 missure. 



I must now notice two other hypotheses as 

 to the office of the cerebellum ; the first is that 

 of Foville; the second that of Gall. Foville 



supposed that the cerebellum is the centre of 

 sensation, " the focus of sensibility." The 

 objections which appear fatal to this hypothesis 

 are derived from anatomy and from patholo- 

 gical observation. The cerebellum wants that 

 general connection with sentient nerves, (direct 

 as well as indirect,) which might be expected 

 if it performed the office in question. Not one 

 of the nerves of pure sense has any connection 

 with it. Moreover the diseased states of cere- 

 bellum do not give rise to any privation of 

 sensibility such as might be expected where 

 the centre of sensation was the part involved. 



The most celebrated view of the office of the 

 cerebellum is that put forward by the distin- 

 guished Gall. He supposed that the instinct 

 of propagation has its seat in this organ, and 

 therefore referred to it as the source of all 

 sexual and generative impulses. 



Gall's view rests on two assumptions ; first, 

 that the instinct of generation or of reproduc- 

 tion is " the most indispensable and most pow- 

 erful of all the instincts;" and, secondly, that 

 great width of the occipital region of the skull 

 and thickness of the back of the neck indicate 

 great developement of the cerebellum. 



It is by reason of the assumed transcendant 

 importance of the generative instinct that so 

 large a portion of the encephalic mass (an 

 eighth or ninth part of the whole) has been 

 assigned by Gall to exercise an exclusive in- 

 fluence over it. 



This first position taken by Gall seems to me 

 untenable. Can we separate the sexual instinct 

 from the emotions, from those especially which 

 are clearly instinctive in their nature ? I ap- 

 prehend not. The same part of the brain 

 would probably exercise its influence upon all 

 the emotional actions. But even if the sexual 

 instinct were separable from the other instincts, 

 it seems very questionable whether it is of that 

 paramount importance as to need a separate 

 organ of great, magnitude, of complex structure, 

 and of extensive connections with the rest of 

 the cerebro-spinal centre. If we compare it 

 with the instinct of self-preservation, as mani- 

 fested in providing either for the wants of the 

 body or for defence against assault, it certainly 

 cannot be admitted lo have a superior influence 

 to this the most pressing of all. Yet, even to 

 this instinct, a separate seat has not been 

 assigned in the brain.* 



The second position which Gall assumes, 



* This argument was used, nearly totidem ver- 

 bis, in Mr. Bowman's and my Physiology in 

 discussing this subject. It and other objections 

 to Gall's doctrine, which we made, have been 

 criticised by Mr. Noble, of Manchester, a most 

 zealous phrenologist, who, like many of that 

 school, is impatient of the slowness of belief 

 of those who do not completely embrace the opinions 

 which he advocates. Mr. Noble seems to think 

 that the existence of a surmise of Spurzhcim's, 

 of a single recorded observation of Dr. A. Combe, 

 which led him to suggest that a certain large convo- 

 lution, seen by him in the brain of a lady who had 

 great fear of death, who evinced " perpetual 

 anxiety about her own death," should be assigned 

 as the seat of a faculty to be called " love of life," 

 and soine observations of Dr. Vimont, which Mr. No- 

 blo docs not value so much as the sinyle observation 



