THE CEREBRUM 131 



will feel pity for the mutilated animal. Instead, he cannot 

 watch it long without finding it amusing. He becomes 

 convinced that it is not a sensitive and suffering creature, 

 but an elaborate mechanical toy. It adjusts itself to 

 external conditions with great success so far as the imme- 

 diate exigency is concerned, but with no anticipation of 

 the future nor reminiscence of the past. In default of 

 stimulation it is relatively inert. It is customary to say 

 that it does nothing spontaneously. The word, however, 

 is a vague one and may well be avoided. An action is 

 called "spontaneous" when we cannot tell how it was 

 caused. Some actions of the decerebrate bird may be 

 placed in this class. 



A pigeon without a cerebrum can be kept alive for 

 weeks, but only by constant care. It will not find food 

 or water for itself, though they may be placed in its cage. 

 In flying and walking it passes around obstacles, but all 

 the evidence goes to show that there is no appreciation 

 of the objects in its path. Another pigeon exists for it 

 simply as a mass of matter, with no more power to stimu- 

 late than a block of wood. The former mate or the young 

 bird appealing for food these are treated merely as 

 things with which a collision is to be avoided. It is 

 clear that the eyes serve well to regulate locomotion with 

 reference to the surroundings, but they are deprived of 

 the power to cause any reaction based upon the indi- 

 vidual experience of the bird. 



Detailed accounts of the behavior of the decerebrate 

 pigoen may be found in larger works and they are full of 

 interest. The main points to be insisted on are (1) that 

 the muscular capabilities of the bird remain little im- 

 paired in the absence of the cerebrum, and (2) that these 

 muscular activities no longer signify that memories 

 connected with the past life of the pigeon are aroused. 

 It is probably fair to claim that the word "memory" in 

 this statement can be used either in its subjective or ob- 

 jective sense. Moreover, it is not only the previous accu- 

 mulation which is destroyed, but also the possibility of ac- 



