THE SPINAL CORD AND CEREBELLUM 131 



because of the very complicated nature of the 

 mechanism we have to deal with, yet a thorough 

 consideration of the following cases will materially 

 help to establish the truth of the above statements. 



' When* in an animal — monkey, cat, or dog, for 

 instance,' says Foster — ' the whole cerebellum is 

 removed, and the immediate effects of the operation 

 have passed away, the condition of the animal is 

 such as to excite wonder that the loss of so large and 

 apparently important an organ has brought about so 

 little change. Its psychical powers do not appear to 

 be at all impaired or changed ; it is as alert and 

 intelligent as before. Sight, hearing, and the other 

 special senses seem unaffected. There are no distinct 

 signs of its cutaneous or general sensibility being 

 deficient or altered. The most that can be observed 

 is a deficiency in its movements ; these are marked 

 by a certain amount of what we may for the present 

 speak of under the general term of " inco-ordination." ' 



The same author then relates the results of the 

 removal of one-half of the cerebellum. This operation 

 leads to no change in the psychical condition nor in 

 the development of sensations, but to an abnormal 

 state of the motor mechanism. If the right half of 

 the organ be removed, ' the animal uses the left side, 

 and especially the left limbs, more than the right ' ; it 

 leans and falls to the right side, and ' shows by the 

 character of its movements that the muscles of the 

 right side are not being worked in a normal manner.' 

 * Poster, loc. cit., p. 1206. 



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