THE PSYCHIC DEVELOPMENT OF YOUNG ANIMALS 121 



When a puppy is removed from the others in its pen 

 it manifests little uneasiness, but quite the reverse if 

 placed on the floor of the kennel, which is covered with 

 sawdust. It creeps about and cries. 



14tk day. Unable to get any evidence of seeing 

 objects, as no sign is given of any kind when various 

 things are moved before the eyes, nor is the winking 

 reflex any better established. 



They seem, as before, to crawl against the board wall 

 of the pen without noticing it. The eyes are more 

 fully opened. 



The loudest noises, including the sounding of a shrill 

 dog-whistle, that can be easily heard a quarter of a 

 mile away, causes no reflex movements of the ears, or 

 any other movement to indicate the possession of 

 hearing. On the other hand, a slight breath of air 

 causes reflex movements. 



To-day I made a definite test of the temperature 

 sense. A glass pestle was heated till it could not be 

 comfortably borne on my skin anywhere, when its end, 

 about half an inch in diameter, was placed against the 

 paw of the puppy, which was rapidly withdrawn. A 

 similar reaction followed the application of ice, but not 

 so quickly. 



They now begin to use the jaws apart from sucking. 

 They stand better and move faster, the hind limbs 

 being, however, much less under control than the front legs. 



I suspected that the beginning of play appeared to- 

 day, but was not quite certain. 



The tendency to growl is manifesting itself in sleep. 



15^ day. Eyelids continue to grow apart, so that 

 more of the globe of the eye can be seen. They seem 

 to wink reflexly a shade more readily under the former 

 tests, but more promptly with the finger close to the 

 eye than with the entire hand moved as close as pos- 

 sible before the face. 



