Although the fetus frequently changes its position during the earlier months of pregnancy, generally by the beginning of the tenth lunar month it has assumed a permanent posture. It has then reached such a size that it can best be accommodated in the cavity of the uterus if its various parts are folded together so as to give the fetus an ovoid shape. To secure this form its back is arched forward, and its head bent so that its chin touches its chest; its arms are crossed just below the head, its legs raised in front of the abdomen, and its knees doubled up. In this form the fetus occupies the smallest possible space.

With relation to the mother the position of the child, for several weeks before birth, is one in which its long axis is parallel to the long axis of her body. This remains true no matter whether the head or the buttocks are to precede at the time of birth. In ninety-seven out of a hundred cases, however, the head lies lowermost and consequently is the first portion of the child to be born. The opposite position, in which the head is the last portion born, is, even with the most skillful treatment, somewhat more serious for the infant, though not for the mother.

THE NEWBORN INFANT.—The baby at birth is not a miniature man. As compared with an adult its head and abdomen are relatively large, its chest relatively small; its limbs are short in proportion to the body; and at first glance it appears to have no neck at all. The middle point of a baby's length is situated about the level of the navel, whereas in a man the legs alone represent approximately half his height. The changes after birth consist chiefly in growth; but not altogether, since at least one organ, the thymus gland, becomes smaller and completely disappears during childhood, and other organs, especially the liver, are proportionately smaller in the adult than in the infant.

The body of the infant also differs from that of the man in possessing greater softness and flexibility. These qualities depend upon the nature of its skeleton, which is composed of more bones than later in life, when several have fused together to form one to give the mature body a more rigid frame. Furthermore, the individual bones are not so firm, consisting of an elastic material called cartilage, so that some movements which in an adult would cause such serious injuries as fractures and dislocations are perfectly harmless to a newborn child.

The legs are not only short in proportion to the body but are always curved, and the feet are held with the soles directed toward one another, a position clearly abnormal in the adult. But every mother should know that these are natural conditions in the infant, and are the result of the posture of the child before birth. They soon straighten out. The bowed legs of an adult are of an entirely different origin, resulting from a disturbance of nutrition in infancy called rickets.

A small amount of short wooly hair is usually found over the back of a newborn infant. More conspicuous, however, is the presence there of a gray, fatty substance which, though always more abundant over the back, is at times distributed over the whole body; rarely is it entirely absent. The material, technically named the vernix, is the product of the glands in the skin and is a perfectly normal secretion. After its removal, which is readily accomplished by greasing the infant with lard or vaselin before giving the initial bath, it never reappears.

A varying amount of hair covers the head of the infant. No significance should be attached to the quantity, for the conviction that exists, especially among negroes, that a heavy suit of hair for the child occasions "heart-burn" in the mother during pregnancy is without foundation. The color of the hair at birth does not indicate its ultimate shade; changes are often noted during infancy. Similarly the permanent color of the eyes is not assumed until later; at the time of birth the eyes are generally, if not always, blue in color.

A baby's head is a matter of great concern to the family. Occasionally, the skull is round and well shaped from the moment of birth, but more often it is long and narrow; sometimes the form is even startling to the inexperienced. The peculiar shape of the head results, of course, from its passage through the birth-canal and is not a sign of any disease. In a few weeks, or even less, the strange appearance passes away. It is unwise to attempt to alter the shape of the head by bandaging or massaging since the growth of the brain will spontaneously accomplish what is desired; interference can do no good, and may do serious harm.

Nature facilitates an appropriate molding of the head during birth so as to permit its easy passage through the bony pelvic cavity of the mother, and gains that end in two ways. The bones of the head remain pliable until after the infant is born, and, further, their edges are not welded together as in an adult, but are separated from one another by an appreciable distance. During the act of birth the edges are brought into contact or even overlap, materially reducing the size of the head. Within a few hours after birth the bones again spread apart, and some months elapse before they begin to unite; the union is not completed until some time during the second year of infancy.

Many mothers are anxious to know how far the senses of the infant have developed when it enters the world. This problem has stimulated some scientific investigation, though hardly so much as its interest would justify. Two lines of inquiry have been pursued toward its solution. The objective point of one of these has been to determine how nearly the sense organs of the newborn correspond anatomically to those of an adult; that is how perfectly has their organization been completed. The other has been to learn how the infant reacts when the various senses are stimulated; the interpretation of these reactions is, however, particularly liable to error and sometimes amounts only to guesswork.