ANIMAL AUTOMATISM. 229 



feed itself, although food put into its mouth is swal- 

 lowed. On irritation, it jumps or walks ; if thrown into 

 the water it swims. If it be put on the hand, it sits 

 there, crouched, perfectly quiet, and would sit there for 

 ever. If the hand be inclined very gently and slowly, 

 so that the frog would naturally tend to slip off, the 

 creature's fore paws are shifted on to the edge of the 

 hand, until he can just prevent himself from falling. 

 If the turning of the hand be slowly continued, he 

 mounts up with great care and deliberation, putting first 

 one leg forward and then another, until he balances 

 himself with perfect precision upon the edge; and, if 

 the turning of the hand is continued, over he goes 

 through the needful set of muscular operations, until he 

 comes to be seated in security, upon the back of the 

 hand. The doing of all this requires a delicacy of co- 

 ordination, and a precision of adjustment of the muscu- 

 lar apparatus of the body, which are only comparable to 

 those of a rope-dancer. To the ordinary influences of 

 light, the frog, deprived of its central hemispheres, 

 appears to be blind. Nevertheless, if the animal be put 

 upon a table, with a book at some little distance between 

 it and the light, and the skin of the hinder part of its 

 body is then irritated, it will jump forward, avoiding 

 the book by passing to the right or left of it. Although 

 the frog, therefore, appears to have no sensation of light, 

 visible objects act through its brain upon the motor 

 mechanism of its body.* 



* Sec the remarkable essay of Goltz, " Beitriigc zur Lchre von den 



