=Head and Chest.= The circumferences of the head and chest are about the same at birth, the chest being possibly a little the smaller of the two. Both measure about 13½ inches, gradually increasing to about 16½ inches in six months and to 18 inches by the end of the first year. =Fontanelles.= The posterior fontanelle, the one at the crown of the head, usually closes in six or eight weeks but the larger, anterior fontanelle is not entirely closed until the baby is about eighteen or twenty months old. =Teeth.= Although it occasionally happens that a baby has one or two teeth at birth, the average infant has none until the sixth or seventh month, when the two lower, central incisors appear. After a pause of a few weeks the two upper, central incisors come through, followed by the two lateral incisors in the upper jaw. At the end of the first year, therefore, the average baby has six teeth, or eight if the lower lateral incisors have appeared by the first birthday, as they sometimes do. This is the usual course of dentition, during the first year, as shown in Fig. 42, but there are wide variations among entirely well and normal babies, the first tooth sometimes not appearing before the tenth, eleventh or even twelfth month. As a rule, however, an entire lack of teeth by the time the baby is a year old is regarded as an evidence of faulty nutrition. [Illustration: FIG. 42.—Diagram showing first, or “milk,” teeth and the ages at which they usually appear. ] The baby who is properly fed and cared for, cuts his teeth with little or no trouble, in spite of the widely current but seriously mistaken belief that a teething baby is a sick baby. We have no way of estimating the number of babies who die, needlessly, as a result of this dangerous conviction, for if the baby is sick while teething, the trouble is all too often accepted as a normal occurrence and is not given the attention it needs until too late. Frail, delicate babies may have convulsions each time that a tooth is cut and if a baby is having digestive trouble, this is likely to grow worse while he is teething. But cutting teeth is a normal process and the healthy, properly fed baby suffers little or no inconvenience while it is in progress. =Stools and Urine.= During the first two or three days the stools are of dark green, tarry material called meconium. In the course of two or three days they begin to grow lighter and shortly the normal stools appear, these being bright yellow in color, of a smooth, pasty consistency and having a characteristic odor. During the first month or six weeks the baby’s bowels may move three or four times daily, but after this they usually move but once or twice in the course of twenty-four hours. As the nourishment is increased, the stools grow somewhat darker and firmer and finally become formed. [Illustration: FIG. 43.—Appearance of cord immediately after birth. ]