THE PSYCHIC DEVELOPMENT OF YOUNG ANIMALS 147 
the cerebrum is but indifferently active as yet, the 
lower nervous centres are constantly receiving impulses 
coming from peripheral parts, the viscera included, and 
if these are of an abnormal or disturbing character, 
there result those forms of expression or external re- 
presentation of the ingoing effects, mostly movements 
which we can correlate with their causes. Hence the 
young animal expresses its feelings of discomfort as 
hunger, cold, etc., by movements, some of which result 
in cries, whining, ete., and experiments, as well as the 
behaviour of animals born without the cerebrum, show 
that the higher parts of the brain may be little 
concerned. 
The feeling of discomfort from being in an atmos- 
phere that is not warm enough, is different somewhat 
from the sensation, likewise disagreeable, of a body 
too cold being placed against the skin. Effects not 
confined to the surface, but modifying the whole of the 
vital processes, result from the former, as it is well 
known that very young animals cannot exist at all 
in a temperature below a certain rather high point as 
compared with that endurable by mature animals. 
Nothing is more striking than the efforts the animal 
makes almost as soon as it is born to place itself in 
an environment of comfort. The importance of this 
instinct—just as fundamental as sucking, ete.—will be 
evident when one considers that the vital processes 
cannot continue except under these conditions. It is 
even more important than that there should be a supply 
of food within the first few hours. 
SUCKING.—Sucking has been so frequently referred 
to by writers as an example of a perfect instinct, that 
I have taken pains to give some details regarding it, 
and to trace its modifications and final decline. 
It will be observed by any one who will, without 
prejudice, examine the subject, that sucking is not 
