THE NERVOUS SYSTEM 301 



the bird is at first dull and inactive, but after a time it 

 regains its power of spontaneous movement. It can fly, 

 avoid obstacles, balance itself on a perch, but it does 

 not recognize its associates, pays no attention to its young 

 and shows no evidence of any knowledge of the things it 

 had previously learned. A German physiologist, Goltz, 

 has succeeded in the difficult operation of removing the 

 entire cerebrum from a dog, and in keeping the animal 

 alive for several months. After recovery from the opera- 



Pic. 214. Median section through brain. A, B, C, D, lobes of the 

 cerebrum; E, cerebellum; F, arbor vitas; H, pons Varolii; K, medulla. 

 (After Leidy.) 



tion the dog was able to walk about spontaneously and 

 even became unusually active. It would growl and snap 

 when its paw was seized and it would eat food placed in 

 contact with its nose, but it would reject meat or milk made 

 bitter with quinine. While the dog could hear and could 

 react to light, it recognized none of its old acquaintances 

 either by sight or sound. Everything it had acquired 

 by memory was lost, and it became a creature of pure in- 



