EXPERIMENTS ON THE CEREBELLUM 173 



This harmonises with the results Ferrier obtained 

 from his stimulation experiments (i). He found that 

 stimulation of the different parts of the cerebellum 

 causes associated movements of the eyes, and that 

 the direction of the movement changes with the posi- 

 tion of the electrodes. The head also moves in the 

 same direction as the eyes. Movements of the limbs 

 were also observed, but it could not be determined 

 whether or not they were associated with the move- 

 ments of the head. From this we may conclude that 

 possibly or probably the movements which are pro- 

 duced by stimulation of the cerebellum are somewhat 

 related to those movements which are produced by 

 stimulation or injury of the semicircular canals, only 

 that the stimulation experiments on the cerebellum, 

 according to Ferrier, often yield no results. 



Extirpation of the cerebellum leaves the sensory 

 and psychic functions of the animal undisturbed. It 

 is only in the movements that peculiar disturbances 

 appear, which are described differently by the differ- 

 ent authors. The motions of the animals resemble 

 somewhat those of a patient suffering from St. Vitus's 

 dance, inasmuch as they do not reach the intended 

 aim and are often excessive in character. It is neces- 

 sary that the head of a dog whose cerebellum has been 

 injured be held in the dish when it eats, for if not held 

 every effort sends the head so much too far that the 

 animal is not able to get its food. This disturbance 

 is most pronounced immediately after the operation 

 and may disappear more or less after a certain time. 



