120 ROBERT M. YERKES 



vations. After she had been returned to her own cage the 

 remnant was noticed on the floor of the large cage. I picked it 

 up. Gertie evidently noticed my act, for although at a distance 

 of at least ten feet from me, she made a sharp outcry and 

 sprang to the side of the cage nearest me. I held the piece of 

 skin (it looked more like a bit of rat skin than the remains of 

 a monkey) out to her and she immediately seized it and rushed 

 with it to the shelf at the top of the cage. 



" Two days later the remnant was missing, and careful search 

 failed to discover it in the cage. It is probable that Gertie had 

 carelessly left it lying on the floor whence it was washed out 

 when the cages were cleaned. On this date Gertie seemed 

 quieter than for weeks previously. 



" Thus it appears, that during a period of five weeks the in- 

 stinct to protect her offspring impelled this monkey to carry its 

 gradually vanishing remains about with her and to watch over 

 them so assiduously that it was utterly impossible to take them 

 from her except by force. 



"After reading this note in manuscript, Doctor Hamilton in- 

 formed me that Gertie had behaved toward her first still-birth 

 as toward her second. And, further, that Grace, a baboon, 

 also carried a still-birth about for weeks. 



" I am now heartily glad that my early efforts to remove 

 the corpse were futile, for this record of the persistence of ma- 

 ternal behavior seems to me of very unusual interest to the 



genetic psychologist . ' ' 



Fear 



In connection with the multiple-choice experiments Skirrl 

 exhibited what seemed to be instinctive fear as a result of his 

 unfortunate experience with nails in the floor of box 1. He 

 seemingly referred his misadventure to some unseen enemy under 

 the floor, and this in spite of the fact that he was given abundant 

 opportunity to examine the floor of the box, but not until after 

 the dangerous nails had been clinched. His long continued 

 avoidance of the experiment boxes and his still more persis- 

 tent hesitancy in entering them, coupled with his almost ludi- 

 crous efforts to see beneath the floor through the holes cut for 

 the staples on the doors, gave me the impression of supersti- 

 tious fear of the unseen. As I watched and recorded his beha- 

 vior day after day during the period of most pronounced fear, 



