Let us see, then, exactly what his condition is. In the first place,
he is, as Virchow, an authority on physiological subjects declares,
merely a spinal animal. Some of the higher brain centers do not yet
exist at all, while others are in too incomplete a state for service.
The various sensations which the baby experiences--heat, light,
contact, motion, etc.--are so many stimuli to the development of these
centers. If the stimulus is too great, the development is sometimes
unduly hastened, with serious results, which show themselves chiefly
in later life. The child who is brought up a noisy room, is constantly
talked to and fondled, is likely to develop prematurely, to talk and
walk at an early age; also to fall into nervous decay at an early age.
And even if by reason of an unusually good heredity he escapes these
dangers, it is almost certain that his intellectual power is not
so great in adult life as it would have been under more favorable
conditions. A new baby, like a young plant, requires darkness and
quiet for the most part. As he grows older, and shows a spontaneous
interest in his surroundings, he may fittingly have more light, more
companionship, and experience more sensations.

[Sidenote: Weight at Birth]

The average boy baby weighs about seven pounds at birth; the average
girl, about six and a half pounds. The head is larger in proportion
to the body than in after life; the nose is incomplete, the legs short
and bowed, with a tendency to fall back upon the body with the knees
flexed. This natural tendency should be allowed full play, for the
flexed position is said to be favorable to the growth of the bones,
permitting the cartilaginous ends of the bones to lie free from
pressure at the joints.