202 FUNCTIONS OF THE NERVOUS SYSTEM. 



the Cerebellum, or in its substance ; but it is to be remembered, that in all 

 such lesions the Medulla Oblongata is involved, and these symptoms, equally 

 with paralysis, may be due to affection of that organ.* Further, the converse 

 does not by any means hold good ; for the proportion of cases of disease of 

 the Cerebellum, in which there is any manifest affection of the sexual organs, 

 is really very small, being, according to the calculations of Burdach, not above 

 one in seventeen. The same physiologist states that such affections do pre- 

 sent themselves, although very rarely, \vhen the Cerebrum is the seat of the 

 lesion. A large number of facts adduced by Phrenologists in support of their 

 views such as the erections and emissions which often take place during 

 hanging may be explained as well, or even better, on the hypothesis that 

 the Cerebro-spinal axis (that is, the Spinal cord with the Medulla Oblongata) 

 is the seat of this instinct. And this hypothesis is much more conformable to 

 the results of experiment and disease than that which locates it in the Cere- 

 bellum. For it has been found that mechanical irritation of the Spinal Cord, 

 and disease in its substance, much more frequently produce excitement of the 

 genital organs, than do lesions of the Cerebellum. This view is entertained 

 by Miiller, and by most physiologists who have taken a comprehensive and 

 unbiased survey of the phenomena in question. 



276. Among the arguments adduced by Gall and his followers in proof of 

 the connection between the Cerebellum and the sexual instinct, is one which 

 would deserve great attention, if the facts stated could be relied on. It has 

 been asserted, over and over again, that the Cerebellum, in animals which 

 have been castrated when young, is much smaller than in those which have 

 retained their virility, being, in fact, atrophied from want of power to act. 

 Now it is unfortunate, that vague assertion, founded on estimates formed by 

 the eye from the cranium alone, is all on which this position rests ; and it will 

 be presently shown, how very liable to error such an estimate must be. The 

 following is the result of a series of observations on this subject, suggested by 

 M. Leuret,t and carried into effect by M. Lassaigne : The weight of the 

 Cerebellum, both absolutely, and as compared with that of the Cerebrum, -was 

 adopted as the standard of comparison. This was ascertained in ten Stallions, 

 of the ages of from nine to seventeen years ; in twelve Mares, aged from seven 

 to sixteen years ; and in twenty-one Geldings, aged from seven to seven- 

 teen years. The average weight of the Cerebrum in the Stallions was 433 

 grammes; the greatest being 485 gr., and the least (which was in a horse of 

 ten years old) being 350. The average weight of the Cerebellum was 61 gr.; 

 the greatest being 65 gr., and the least 56 gr. The average proportion borne 

 by the weight of the Cerebellum to that of the Cerebrum, was, therefore, 1 to 

 7-07 ; the highest (resulting from a very small Cerebrum) being 1 to 6-25 ; 

 and the lowest (resulting from an unusually large Cerebrum) being 1 to 7'46. 

 Throughout it might be observed, that the variation in the size of the Cerebellum 

 was much less than in that of the Cerebrum. In the twelve Mares, the average 

 weight of the Cerebrum was 402 gr. ; the highest being 432 gr. and the lowest 

 336 gr. That of the Cerebellum was 61 gr. ; the highest being 66 gr. (which 

 was in the individual with the smallest Cerebrum), and the lowest 58 gr. 



* A case has been recently communicated to the Author, in which the sexual desire, 

 which had been always strong through life, but which had been controlled within the 

 limits of decency, manifested itself, during: a period of some months preceding death, in 

 a most extraordinary degree; on post mortem examination, a tumour was found on the 

 Pons Varolii. This fact harmonizes with the view given in the text ( 278), that the 

 sexual instinct, if connected with the cerebellum at all, has its seat in the central lobe; 

 but it also corresponds equally well with the idea, that the Medulla Oblongata is its 

 centre. 



f Anat. Comp. du Systdme Nerveux, torn. i. p. 427. 



