THE MODIFICATIONS IN LACTATION.
We have seen that during pregnancy, the breasts undergo marked changes, and that in many women, it is possible at the end of pregnancy to express a few drops of milk from the breasts. But this milk is serous, yellow, and contains only a few true milk globules. From the second day, oftener the third after delivery, the milk is secreted.
According to Schroeder, the sources of the milk are two. The liquid portion is a simple transudation from the blood, and the morphological elements come from the gland cells of the breast. In these glands, under the influence of swelling of the cells, there is produced a finely granular deposit, which unites into drops of fat. (Figs. 263 to 265.) The primitive glandular cells, round, finely granular, which have lost their nuclei, are known as colostrum corpuscles. Finally, these break up into fat drops of different size, and, together with the transudation from the blood, form an emulsion: this is the milk. (Schroeder.) The colostrum, which is yellow-white and sweet to the taste, contains much butter and sugar. When fresh it is alkaline.
Simon, in 100 parts of colostrum, found: Solids 17.20; casein 4; sugar 7; butter 5. The perfected milk contained only 11.23 solids.
Marchand, in 100 parts of colostrum, found: Proteids 17.20; lactine 6.30; butter 4.50; salts .25; water 71.63.
In 100 parts of milk, he found: Proteids 1.90; lactine 5.30; butter 4.50; salts .18; water 88.12.
Under the microscope, milk contains a large number of semi-transpar. ent globules, varying in size, and isolated epithelial cells, at times mucous globules. According to Raspail, the milk globules are composed of albu min and of fat; Henle and Simon believe that their coating is casein, and their contents is fat. Donne and H. Nesse believe that the milk globules are simply fat. According to Schroeder, the fatty parts of the milk are composed of albuminoid matter, and the albumin of the colostrum is transformed into casein. Kemmerich has shown that in colostrum fresh from. the breasts, casein increases as albumin diminishes; nevertheless, according to Zahn, perfect milk contains a little albumin. Kehrer says that the casein is contained within the debris of the glandular cells, which, swollen, and rendered invisible, make,, with the serum of the milk, a clear mucus, and determine the emulsion of the fat globule.
The colostrum contains fat globules (often, also, mucous corpuscles, and pavement epithelial cells), and, in addition, granular, round corpus cles, yellow in color, larger than the milk globules, and these corpuscles are known as colostrum corpuscles, granular bodies of Donne, who first described them. They are in particular abundant in the first days of the puerperium, and do not completely disappear till the fifth or sixth day, according to Donne, till the end of a few weeks, according to other authorities.
Milk contains a mixture of fat drops, more or less voluminous, and these are the milk corpuscles, which are surrounded by an albuminoid mem brane, which Ascherson has called the haptogene membrane. (Naegele and Grenser.) The phenomena which accompany the establishment of the function of lactation have been carefully studied by Chantreuil, and he makes the distinction into local and general phenomena.
Local are the increase in size and in consistency of the breasts, the excretion of the milk, the changes in the nipples.
At the end of the second day, usually during the third, the breasts in crease in size, the skin becomes tense, traversed by bluish vessels. The nipples project less. At the moment of the appearance of the milk, the milk ducts are felt hard under the skin. If the breast be squeezed at the level of the nipple, the milk exudes. Frequently, above all in the primipara, an cedema, generally localized at the areola, results. When the function of lactation is established, sugar appears in the urine. Ac cording to Blot, glycosuria is a constant accompaniment of the appearing with the milk, and disappearing at the end of lactation. Blot calls it, on account of its constancy, physiological glycosuria. Le Conte denies the truth of Blot's assertion, and says that the reaction obtained by him was not that of sugar, but of uric acid. The researches of Ben ecke, Winckel, etc., in Germany confirm Blot's opinion.