THE PSYCHIC DEVELOPMENT OF YOUNG ANIMALS 121 
When a puppy is removed from the others in its pen 
it manifests little wneasiness, but quite the reverse if 
placed on the floor of the kennel, which is covered with 
sawdust. It creeps about and cries. 
14th 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paw of the puppy, which was rapidly withdrawn.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 undercontrol 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. 
15th 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 Bone moved as close as pos- 
sible before the face. 
