10 years 51 " 64 " } {Gained 2 in. and 6 lbs. 11 years 53 " 70 " } {a year. 12 years 55 " 79 " } 13 years 57 " 88 " } 14 years 59 " 100 " } {Gained 2 inches and 15 years 61 " 109 " } {about 9 lbs. a year. 16 years 63 " 117 " } GENERAL DEVELOPMENT The accompanying illustration (Fig. 14), taken from Dr. Yale, represents the developmental changes at one, five, nine, thirteen, seventeen, and twenty-one years. Each figure is divided into four equal parts, and as we watch the development from the baby who at one year, as Dr. Yale says, is four heads high, at the age of twenty-one the legs and the trunk have much outgrown the growth of the head, so that at this age the head is only two-thirteenths or less of the whole length of the body. The legs have grown more rapidly and equal one-half the entire body length. The trunk has not kept pace with the legs, for as you will see from the diagram the line reaches the navel of the child in one year, while in the adult it is much lower. The rapid growth of the legs is accomplished after nine years of age. [Illustration: Fig. 14. Developmental Changes] The proportions of the head, chest, and abdomen are exceedingly important in the growing child. At the end of the first year the head, chest, and abdomen are about uniform in circumference. The head may measure one-fourth of an inch more, but the chest and abdomen should both measure eighteen inches in circumference at this time. Should the head or the abdomen be two inches larger than the chest; the attention of the physician should be called to it, for either are indicative of conditions that should be carefully investigated. NORMAL BREAST WEANING As a general rule the normal, healthy, breast-fed baby is given a feeding of a bottle each day after he is ten months old. These bottles are increased in number until, by the time the baby is a year old, he is gradually weaned from the breast. Should the ninth month of baby's life arrive in the hot summer months we urge the mothers to continue breast feeding, with possibly the addition of some fruit juices, as noted elsewhere, until early autumn. Under no circumstances should the baby be weaned and compelled to use cow's milk during the season of the year when the risks of contamination are greatest. If the baby is nursed up to the close of his first year he hardly need be trained to use the bottle, but may take his food from a cup. From one to two months should always be consumed in weaning the baby, unless sudden weaning is necessitated by ill health, as noted elsewhere. The baby should have, if possible, from thirty to forty days to accustom himself to cow's milk exclusively.