418 THE NERVOUS SYSTEM. 



absolute weight of the cerebellum is 61 grains, and in geldings 

 70 grains ; and its proportionate weight, compared with that 

 of the cerebrum, is, on average, as 1 : 6.59 in mares ; as 1 : 5.97 

 in geldings, and only as 1 : 7.07 in stallions. 



On the whole, therefore, it appears advisable to wait for 

 more evidence before concluding that there is any peculiar and 

 direct connection between the cerebellum and the sexual in- 

 stinct or sexual passion. From all that has been observed, no 

 other office is manifest in it than that of regulating and com- 

 bining muscular movements, or of enabling them to be regu- 

 lated and combined by so informing the mind of the state and 

 position of the muscles that the will may be definitely and 

 aptly directed to them. 



The influence of each half of the cerebellum is directed to 

 muscles on the opposite side of the body ; and it would appear 

 that for the right ordering of movements, the actions of its two 

 halves must be always mutually balanced and adjusted. For 

 if one of its crura, or if the pons on either side of the middle 

 line, be divided, so as to cut off from the medulla oblongata 

 and spinal cord the influence of one of the hemispheres of the 

 cerebellum, strangely disordered movements ensue. The ani- 

 mals fall down on the side opposite to that on which the crus 

 cerebelli has been divided, and then roll over continuously and 

 repeatedly ; the rotation being always round the long axis of 

 their bodies, and from the side on which the injury has been 

 inflicted. 1 The rotations sometimes take place with much ra- 

 pidity ; as often, according to M. Magendie, as sixty times in a 

 minute, and may last for several days. Similar movements 

 have been observed in men ; as by M. Serres in a man in whom 

 there was apoplectic effusion in the right crus cerebelli ; and by 

 M. Belhomme in a woman, in whom an exostosis pressed on 

 the left crus. 3 They may, perhaps, be explained by assuming 

 that the division or injury of the crus cerebelli produces paral- 

 ysis or imperfect and disorderly movements of the opposite 

 side of the body ; the animal falls, and then, struggling with 

 the disordered side on the ground, and striving to rise with the 



1 Magendie and Miiller, and others following them, say the rotation 

 is towards the injured side ; but Longet and others more correctly 

 give the statement as in the text. The difference has probably arisen 

 from using the words right and left, without saying whose right and 

 left are meant, whether those of the observer or those of the observed. 

 When, for example, an animal's right crus cerebelli is divided, he 

 rolls from his own right to his own left, but from the left to the right 

 of one who is standing in front of him. 



8 See such cases collected and recorded by Dr. Paget in the Ed. 

 Med. and Surg. Journal for 1847. 



