LACTATION. 27 



established. The oil-globules of the milk are formed by a 

 sort of fatty degeneration of the gland-cells, which finally 

 fall to pieces; the cream is thus set free in the watery and 

 albuminous secretion formed simultaneously, while newly 

 developed gland-cells take the place of those destroyed. In 

 the milk first secreted after accouchment (the colostrum) the 

 cell destruction is incomplete, and many cells still float in the 

 liquid, which has a yellowish color; this first milk acts as a 

 purgative on the infant, and probably thus serves a useful 

 purpose, as a certain amount of substances (biliary and 

 other), excreted by its organs during development, are found 

 in the intestines at birth. 



Human milk is undoubtedly the best food for an infant 

 in the early months of life; and to suckle her child is useful 

 to the mother if she be a healthy woman. There is reason 

 to believe that the processes of involution by which the large 

 mass of muscular and other tissues developed in the uterine 

 walls during pregnancy are broken down and absorbed, 

 take place more safely to health if theTiatural milk secretion 

 is encouraged. Many women refuse to suckle their children 

 from a belief that so doing will in jure their personal appear- 

 ance, but skilled medical opinion is to the contrary effect; 

 the natural course of events is the best for this purpose, 

 unless lactation be too prolonged. Of course in many cases 

 there are justifiable grounds for a mother's not undertaking 

 this part of her duties; a physician is the pioper person to 

 decide. 



In a healthy woman, not suckling her child, ovulation and 

 menstruation recommence about six weeks after childbirth; 

 a nursing mother usually does not menstruate for ten or 

 twelve months; the infant should then be weaned. 



When an infant cannot be suckled by its mother or a wet- 

 nurse an important matter is to decide what is the best food 

 to substitute. G-ood cow's milk contains rather more fats 

 than that of a woman, and much more casein; the following 

 table gives averages in 1000 parts of milk: 



Woman. Cow. 



Casein 28.0 54.0 



Butter 33.5 43.0 



Milk sugar 44.5 42.5 



Inorganic matters 4.75 7.75 



