417 



secrete, has always been considered as very like the chyle, which it re- 

 sembles in its white colour, its smell, and its saccharine taste. Like the 

 chyle, it is the least animalized fluid, the sweetest, that on which the ac- 

 tion of the organs produces the least effect, and that which preserves 

 most the characteristic qualities of the food taken by the nurse. 



It is well known, that instead of giving medicines to infants at the 

 breast, we most frequently administer the medicine to the nurse ; thus, 

 the milk acquires purgative qualities, and acts on the bowels of the child, 

 when the nurse has been purged*. The chyle is white and opaque, only 

 in those animals which suckle their young ; in the others, it is as trans- 

 parent as lymph. (Cuvier.) 



In the last place, if the arteries carried to the breasts the materials of 

 their secretion, these vessels ought to increase in size, when these organs 

 become twice, or even three or four times larger than natural; in the 

 same manner that, in open cancer, and in other similar affections, in 

 jwr.hich the determination of blood being increased, the calibre of the ves- 

 sels is proportioned to them. Nothing, however, of the same kind occurs, 

 whatever size the breasts may acquire from the presence of milk ; their 

 arteries preserve their almost capillary minuteness, as I had an oppor- 

 tunity of ascertaining, by injecting the mammae of a woman twenty-nine 

 years of a|*e, who died in the second month of suckling, and whose breasts 

 were remarkable by their size, and by the quantity of milk they were able 

 to secrete. 



Notwithstanding all these reasons, which have long made me adopt the 

 opinion of the celebrated Haller, who considers the milk as immediately 

 extracted from the chyle, I own that it must be considered as hypotheti- 

 cal, and resting solely on probability. The impossibility of demonstra- 

 ting, anatomically, the branches going from the mesentery to the breasts, 

 without communicating with the thoracic duct, gives still greater proba- 

 bility to the generally received opinion, which makes the milk, like all 

 the other secreted fluids, with the exception of the bile, to be supplied by 

 arterial bloodf. 



The milk does not resemble chyle, in every respect, though it may .be 

 considered as extracted from the food|, changed in its way to the mam- 

 mae, by the glands through which it has passed, and especially by the ac- 

 tion of the organs themselves. This action is so evident, that, as Bordeu 

 observes, "There are women who seem to have no milk in their breasts, 

 which are flaccid and empty ; but as soon as the child excites them, they 

 become distended, and the milk comes spontaneously." It is well 

 known, and the same author has pointed it out, that women, cows, and 

 the females of other animals, allow themselves more willingly to be sucked 

 by a suckling that knows how to excite their sensibility, and to apply due 

 iritation to the nipple ; and that, on the contrary, they retain their milk, 



* This only takes place when such purgatives are used as are readily absorbed into 

 the circulation. Copland. 



f The passage of injections from the arteries into the lactiferous tubes, and the cir- 

 cumstance of blood having 1 been drawn from an exhausted breast, when the child has 

 been allowed to suck too Jong- ; and, lastlj;, analogy, leave no doubt of the true source 

 of the fluid secreted by the mainmie. Copland. 



" Lac utilis aliment! superfluum." Gal. De Usu part. Lib. VII. Cap. XXII. 



