130 K. S. LASHLEY AND JOHN B. WATSON 



September 10. Up to today signs of sex activity or interest 

 have been lacking. Today erection appeared. Mother had 

 fed, and had carried baby to the shelf. He was restless and 

 danced about trying to get down. She tried to nurse him three 

 or four times but he always struggled to free himself. Finally 

 she held on tightly to him and began to pick him around the 

 sex organs. Erection appeared. The mother continued to pull 

 at organ and to push back fore-skin. Baby became very quiet 

 and began to nurse, pulling at the short rope attached to her 

 collar with one hand and reaching back to play with his own 

 sexual organs. I have seen the mother pick over his sexual 

 organs often before but this never before produced an erection. 

 Apparently the testicles have not yet descended. They are 

 plainly apparent, being lodged about two inches from the end 

 of the scrotum. Whether there is any actual descension or 

 merely downward growth from this point is not easy to say. 



September 12. Baby very active. Mother at first would not 

 come down for food. Young monkey made several tentative 

 efforts. Finally mother came down without him leaving him 

 upon the shelf. He was frantic and cried and danced in rage. 

 She paid not the slightest attention to him and even when she 

 went back she did not take him up or allow him to nurse. He 

 was very eager to eat of her milk soaked bread but dared not 

 reach for it. He made several playful strikes, rearing up on 

 hind legs and striking with fore feet. Several times when he 

 attempted to nurse she pulled him away and put her head down 

 on a level with his and frowned in his face. We have here 

 another step in the process of separation between the two. 



September 12-1S. Tenth week. 



Eyes, which were deep blue at first, have changed into brown, 

 characteristic of species. No evidence yet of cutting of molars. 

 Seems to be slow period of development. 



October 21, 22, 2j. Fifteenth week. 



For several weeks development of new responses has been 

 slow. The monkey has been in the best of health and growth 

 is apparently normal. 



On the above dates it was noted that the young monkey was 

 able to run down and up the inclined plane very readily. Long 



