516 OF THE NERVOUS SYSTEM AND ITS ACTIONS. 



910. There is another doctrine, however, in regard to the functions 

 of the Cerebellum, first propounded by Gall ; which ought not to be 

 altogether passed by. According to the system of Phrenologists, the 

 Cerebellum is the organ of the sexual instinct ; and its connexion with 

 the motor function is limited to the performance of the movements, to 

 which that instinct leads. This doctrine derives no support, however, 

 from the facts supplied by Comparative Anatomy ; for there is a com- 

 plete want of correspondence between the size of the Cerebellum in 

 different animals, and the power of their sexual instinct. Again, 

 although Pathology has been appealed to, as showing a decided con- 

 nexion between disease of the Cerebellum and affection of the Genital 

 organs (manifesting itself in priapism, turgescence of the testes, seminal 

 emissions, &c.), yet it appears, on a careful examination of evidence, 

 that such a sympathy is comparatively rare, not being displayed in 

 more than one out of every seventeen cases of Cerebellic disease. And 

 where it is manifested, it is explicable quite readily by the known fact, 

 that this kind of excitement of the genital organs may be produced by 

 excitement of the spinal cord and medulla oblongata. Little or no 

 light has been thrown on this question by experiment. It was asserted 

 by Gall, that the Cerebellum is very small in castrated animals ; but 

 this assertion has been met by the most positive counter-statements on 

 the part of Leuret, who has shown that the average weight of the Cere- 

 bellum (both absolutely, and in proportion to the weight of the entire 

 encephalon) is even greater in Geldings, than in Stallions or Mares. It 

 is asserted, however, that the results of observation in Man lead to a 

 positive conclusion, that the size of the Cerebellum is a measure of 

 the intensity of the sexual instinct in the individual. This assertion 

 has been met by the counter-statement of others, that no such relation 

 exists. There are, of course, very great difficulties in regard to the 

 collection of accurate information on this subject ; and the question 

 must be at present regarded as sub judice. 



911. It may be added, that the idea of a special connexion between 

 the sexual instinct and the Cerebellum, is not inconsistent with the view 

 of its function previously stated ; and it would seem to derive some 

 confirmation from the fact, that an unusual amount of muscular exer- 

 tion appears to have a peculiar tendency to depress the sexual passion, 

 even whilst it increases the general vigour of the system. If the Cere- 

 bellum be really connected with both kinds of functions, it does not 

 seem unlikely that the excessive employment of it upon one, should 

 diminish its energy in regard to the other. Further, it seems not 

 improbable, that the Lobes of the Cerebellum are the parts specially 

 concerned in the regulation of the muscular movements ; whilst the 

 central portion (constituting the Vermiform process in Man, but form- 

 ing the entire cerebellum of many of the lower Vertebrata, such as the 

 Prog) may contain the centre of the sexual sensations, and may thus be 

 the instrument of the consensual actions to which they give rise. 



7. Functions of the Cerebrum. 



912. The view which has been taken of the Comparative structure of 

 the Nervous system, in different animals, leads to the conclusion, that 



