NERVOUS CONTROL OF ANIMAL MOVEMENTS. 349 



into a revolving motion, and turns on himself like a ball. The former 

 movements are chiefly produced by lesions of the encephalon, and were 

 obtained very neatly in a frog from which were removed the cerebral 

 lobes of the left side. The movements were made from the left side 

 toward the right. 



What fixed attention at first in the attitude of this frog was, that 

 all the right part of the body had the carriage and aspect of a frog 

 without a cerebrum (Fig. 2). The hind-foot of this side approached 

 the body more, and was gathered in a heap, as shown in Fig. 3, while 

 the fore-foot was equally drawn up, and had the position that we have 



Fig. 3. 



A Frog that has lost the Left Half of the Cerebrum. 



seen to be constant in frogs in which the cerebrum had been removed. 



At the same time, the entire animal leaned a little to the right side. 

 This inclination of the body is neither constant nor inevitable with 

 animals which have only the movements in a circle ; it is, on the con- 

 trary, constant and forced with those that have the turning motion. 



The attitude of this frog changed, and was even reversed, when it 



