l6 Journal of Comparative Neurology and Psychology. 



February 14. Y was in the cage with a gray mouse for fifteen 

 minutes. She followed it about striking it gently with her paws. 

 When it ran up the side of the cage she ran up after it and brought 

 it down in her mouth, but she did not injure it. 



February 15. The same gray mouse was put into the cage with 

 Z for twenty minutes. The mouse climbed up to the top of the 

 cage. Z went up and smelled of it four times before she knocked 

 it down with her paw. She did not pay very much attention to 

 it during the last five minutes. 



February 15, Y was put in with the mouse for twenty minutes. 

 He soon discovered it up at the top of the cage. After he had 

 gone up and smelled of it three times he seized it with his teeth 

 and threw it down. He switched his tail and his claws rattled 

 on the floor as he ran after it, but he never growled. In all of 

 these trials the cats had not been fed meat for at least twenty-four 

 hours. 



February 16. A white mouse was put in with X. The cat 

 played with it as usual. After a few minutes M (the mother cat) 

 was put into the cage with X. She killed and ate the mouse 

 while X looked on. X did not dare to approach as M growled 

 very ominously whenever X moved. After M had finished eating 

 the mouse I took her out and put another mouse in with X. She 

 played with it just as she had played with the other one. I could 

 not see that her behavior was influenced in the least by the tragedy 

 she had just witnessed. When Z was put into the cage with her 

 X seized the mouse in her mouth whenever Z approached, but 

 as long as Z did not move she played with it as usual. When the 

 mouse was given to Z she would not let X have it. After a few 

 minutes Z was taken out and M was put in with X. M killed the 

 mouse at once and began to play with it. She let X have it, but 

 the latter would not eat it, until M had exposed the raw flesh; then 

 she ate it at once. M was now removed and another mouse put 

 in with X. She played with it as usual, but made no attempt to 

 kill it. 



February 19. A white mouse was put into the cage with X for 

 ten minutes. She was no rougher w^ith it than usual. But when 

 Y was put in with her she seized the mouse and began to growl. 

 When the mouse ran toward Y he did not attempt to seize it even 

 when it was nearer to him than it was to X. After removing Y, 

 I fed M a little meat in sight of X. She at once left the mouse, 



