Dr. Edgar estimates that the loss through the lochia amounts to something over three pounds, and the loss through fluids from the tissues, from nine to ten pounds. According to Dr. Slemons, the loss in fluids equals about 1/10th of the patient’s weight at the beginning of the puerperium, while all agree that the uterus decreases about two pounds in weight. All told, then, the patient may normally lose from twelve to fifteen pounds during the puerperium. This loss may be somewhat controlled, however, by a suitable diet, and under most conditions the patient should return to not less than her pre-pregnant weight by the end of the sixth or eighth week. =Menstruation.= Although in the ideal course of events, the mother does not menstruate while nursing her baby, that is, for eight to ten months, Dr. Slemons estimates that about one-third of all nursing mothers begin to menstruate about two months after delivery, while according to Dr. Edgar one-half of those who do not nurse their babies begin to menstruate in six weeks after delivery. Menstruation is more likely to return early in primiparæ than in multiparæ. Patients sometimes wonder whether this early discharge is menstrual or lochial, and though they can not tell, a physician can easily decide by examination, and it is important that he be given the opportunity to do so. A nursing mother may menstruate once and then not again for several months or a year; or she may menstruate regularly and nurse her baby satisfactorily at the same time, though menstruation is usually regarded as unfavorable to lactation. =Lactation.= During the first two or three days after the baby is born, the breasts secrete a small amount of yellowish fluid called colostrum, which differs from milk chiefly in that it contains less fat and more salts and serum-albumen than milk and in the fact that it coagulates upon boiling. About the third day after delivery, the meagre amount of colostrum is replaced by milk and as it increases rapidly in amount, the breasts usually become tense and swollen at this juncture, and sometimes very painful; but this turgidity usually subsides after a day or two. The function of the breasts, that of secreting milk, is definitely stimulated by the baby’s suckling and will not continue for more than a few days without this stimulation, a fact to be remembered if it is desirable for any reason to dry up the breasts. The ideal condition is for the breasts to secrete a quantity and quality of milk which will adequately nourish the baby for eight or ten months. The reverse of this condition is sometimes found in very young or in elderly women, or in very fat or frail, undernourished women.