CHAP. XI.] FUNCTIONS OF THE CEREBELLUM. 361 



connected slightly indeed with the hemispheres of the brain, but 

 most extensively with the mesocephale, the medulla oblongata, and 

 the spinal cord. Now it is not unworthy of notice that its connexion 

 with the brain proper is more immediately with that part which we 

 regard as the centre of sensation ; namely with the optic thalami, 

 through the processus cerebelli ad testes. And it cannot be doubted 

 that the muscular sense materially assists in the co-ordination of 

 movements. 



The cerebellum is connected with the medulla oblongata and 

 spinal cord by the restiform bodies, and the posterior columns of 

 the cord, and with the mesocephale by the fibres of the pons. 

 Thus this organ is brought into union with each segment of 

 the great nervous centre, upon which all the movements and 

 sensations of the body depend. It would be difficult to con- 

 ceive any other affection for which so elaborate a provision would 

 be necessary, excepting that of regulating and co-ordinating 

 the infinitely complex movements which the muscular system is 

 capable of effecting; more especially when it is plain that the 

 antero-lateral columns of the cord and the anterior pyramids 

 and olivary columns supply all the anatomical conditions which 

 may be necessary for the development of acts of sensation and 

 volition. 



So far, then, we derive from experiment and from anatomy argu- 

 ments highly favourable to Flourens' theory of the use of the cere- 

 bellum. The results of pathological inquiry afford no satisfactory 

 information on this point ; for so closely connected are the trans- 

 verse fibres of the pons with the anterior pyramids in the meso- 

 cephale, that the morbid influence of any deep-seated lesion of 

 either hemisphere of the cerebellum is very readily transferred to 

 that segment, and produces symptoms precisely resembling those of 

 lesion of either cerebral hemisphere. The signs referrible to cerebellar 

 lesion are therefore obscured by those which result from the affection 

 of the pyramidal bodies. A few cases, however, have been put on 

 record in which a tottering gait, like that of a drunken man, and a 

 defective power of co-ordination existed in connexion with a dis- 

 eased state of cerebellum.* 



It remains for us to notice the celebrated theory of Gall, that the 

 instinct of propagation has its seat in the cerebellum; which, indeed, 

 according to the author of the theory, and the majority of his followers 

 of the phrenological school, is exclusively devoted to that function. 



* Andral, Clin. Med. t. v.p.428. 



