The milk of all animals contains a relatively small quantity of mineral matter; judged from this standpoint, the mineral matter would seem of minor importance, but it is actually as vital as any other constituent. Without it the bones would hot harden properly; and other services which it performs are absolutely essential to life. As we should expect, human milk contains all the mineral ingredients necessary for the development of the infant; indeed, with the single exception of iron, they are present in the precise amounts in which they are needed. In this omission, however, nature is guilty of no oversight, since the infant has already been provided by the time of birth with a rich supply of iron. THE TECHNIQUE OF NURSING.--Since the mother should have opportunity to recuperate from the fatigue of labor, physicians generally recommend that an interval of at least twelve hours elapse between the birth of the infant and the time it is first put to the breast. Moreover, the best interests of the infant demand that it be kept warm and left undisturbed while becoming accustomed to its new environment. There is no immediate need of food; and if there were, nature does not fit the mother to supply it, for at this time the breasts contain merely small quantities of colostrum. Some babies nurse vigorously at the outset, but later, discouraged because they get so little, become indifferent and restless, or even decline to take the breast. And the mother, who is handicapped by inexperience and by the awkwardness of nursing in a recumbent position, often feels desperate. Fortunately technical difficulties are confined to the first few days, and, trying as they sometimes are, no one should be discouraged or imagine that she is incapable of nursing; for practically every woman who persists will succeed. For a week or ten days the mother will nurse in the recumbent posture. She turns to one side or the other, according as the right or left breast is used, and holds the corresponding arm to receive and support the baby, which will lie beside her. Then with the opposite hand she holds the breast, placing her thumb above and her fingers below so as to keep it from the baby's face, for only in this way can the infant breathe freely. One must also remember that the infant draws the milk into the terminal ducts chiefly with the back of its mouth, and drains the ducts by compressing the base of the nipple with its jaws; the infant therefore should take into its mouth not only the nipple, but also the areola, the area of deeply colored skin round about it. Mothers frequently disregard these directions, and the failure of their infants to nurse properly may be thus explained, for it is impossible to secure undisturbed nursing unless they are obeyed.