FUNCTIONS OF THE CEREBELLUM. 527 



however, are produced by removing parts of its substance. 

 Flourens (whose experiments have been abundantly con- 

 firmed by those of Bouillaud, Longet, and others) extir- 

 pated the cerebellum in birds by successive layers. Feeble- 

 ness and want of harmony of the movements were the 

 consequence of removing the superficial layers. When he 

 reached the middle layers, the animals became restless 

 without being convulsed ; their movements were violent 

 and irregular, but their sight and hearing were perfect. 

 By the time that the last portion of the organ was cut 

 away, the animals had entirely lost the powers of spring- 

 ing, flying, walking, standing, and preserving their equi- 

 librium. When an animal in this state was laid upon its 

 back, it could not recover its former posture ; but it 

 fluttered its wings and did not lie in a state of stupor ; it 

 saw the blow that threatened it, and endeavoured to avoid 

 it. Volition, sensation, and memory, therefore, were not 

 lost, but merely the faculty of combining the actions of the 

 muscles ; and the endeavours of the animal to maintain its 

 balance were like those of a drunken man. 



The experiments afforded the same results when repeated 

 on all classes of animals ; and, from them and the others 

 before referred to, Flourens inferred that the cerebellum 

 belongs neither to the sensitive nor the intellectual appa- 

 ratus ; and that it is not the source of voluntary movements, 

 although it belongs to the motor-apparatus ; but is the 

 organ for the co-ordination of the voluntary movements, or 

 for the excitement of the combined action of muscles. 



Such evidence as can be obtained from cases of disease of 

 this organ confirms the view taken by Flourens ; and, on 

 the wiiole, it gains support from comparative anatomy; 

 animals whose natural movements require most frequent 

 and exact combinations of muscular actions being those 

 whose cerebella are most developed in proportion to the 

 spinal cord. 



M. Foville holds that the cerebellum is the organ of 



