MILK. 83 



entirely disappears from the secreting culs-de-sac during the 

 period of greatest functional activity of the gland, and 

 nothing is left to perform the work of secretion but the 

 amorphous membrane of the vesicles. 



Conditions which modify the Lacteal Secretion. Yery 

 little is known concerning the physiological conditions -which 

 modify the secretion of milk. When lactation is fully 

 established, the quantity and quality of the milk secreted 

 become adapted to the requirements of the child at differ- 

 ent periods of its existence. In studying the composition 

 of the milk, therefore, it will be found to vary considerably 

 in the different stages of lactation. It is evident that, as 

 the development of the child advances, a constant increase 

 of nourishment is demanded ; and, as a rule, the mother is 

 capable of supplying all the nutritive requirements of the 

 infant for from eight to twenty months. 



During the time when such an amount of nutritive mat- 

 ter is furnished to the child, the quantity of food taken 

 by the mother is sensibly increased ; but observations have 

 shown that the secretion of milk is not much influenced by 

 the nature of the food. It is necessary that the mother 

 should be supplied with good, nutritious articles ; but as 

 far as solid food is concerned, there seems to be no great 

 difference between a coarse and a delicate alimentation ; 

 and the milk of females in the lower walks of life, when the 

 general condition is normal, is fully as good as in women 

 who are enabled to live luxuriously. It is, indeed, a fact gen- 

 erally recognized by physiologists, that the secretion of milk is 

 little influenced by any special diet, provided the alimenta- 

 tion be sufficient and of the quality ordinarily required by 

 the system, and that it contain none of the few articles of 

 food which are known to have a special influence upon lac- 

 tation. So long as the mother is healthy and well nourished, 

 the milk will take care of itself; and the appetite is the 

 surest guide to the proper variety, quality, and quantity of 



