52 STELLA BURNHAM VINCENT 



These hairs are probably dead but occasionally there is a hair 

 which causes a squeal when pulled. 



Here are some more notes taken from those of the animals 

 which were used in the discrimination tests. They are reported 

 here because the behavior seems significant. 



July 22, (ii weeks). Rats tested again today. Lip still 

 insensitive. There is one thing noticeable for the last week or 

 so. If they are taken up in the hand they root with their snouts 

 like little pigs. The act is quite unlike the dainty touches which 

 they usually give with their noses and vibrissae. Differences 

 in the vibrissae are still to be seen but they are not so marked. 

 Many of the old hairs have fallen and new ones are coming in. 



Aug. 7, (13 weeks). There appears to be a little sensitivity 

 among the outer vibrissae, not when pulled or touched but the 

 skin about them seems to be a little sensitive. There is still 

 the same rooting action with the snout. 



Aug. 17, (15 weeks). The animals are refusing to open the 

 swinging doors of the box which they have before pushed open 

 easily with a blow of the nose. They come up to the door, sit 

 before it and wait for it to be opened for them. There appears 

 to be no reason for this unless their noses are growing hyper- 

 sensitive. The doors swing freely from above, are very light 

 and have caused no trouble previously but if they are not pushed 

 with sufficient force they sometimes swing back before the 

 animal gets through and strike the nose or head. The normal 

 animal does not mind this but these seem to. The behavior is 

 becoming very marked in all. 



