668 MILK. 



seems to cause no constant, direct action on the quantity of the milk 

 constituents. 1 From feeding experiments with different foods we come 

 to the conclusion that the character of the food is of comparatively little 

 influence, while the race and other conditions play an important role. 

 Watery food gives a milk containing an excess of water and having little 

 value. In the milk from cows which were fed on distillers' grain COM- 

 MAILLE 2 found 906.5 p. .m. water, 26.4 p. m. casein, 4.3 p. m. albumin, 

 18.2 p. m. fat, and 33.8 p. m. sugar. Such milk has sometimes a peculiar 

 sharp after-taste, although not always. TANGL and ZAixscHEK 3 could 

 not find any difference in the average composition of the milk produced 

 after feeding with dry and with moist fodder. 



Chemistry of Milk-secretion. That the constituents which occur 

 actually dissolved in milk pass into the secretion and not alone by filtra- 

 tion or diffusion, but more likely are secreted by a specific secretory 

 activity of the granular elements, is shown by the fact that milk-sugar, 

 which is not found in the blood, is to all appearances formed in the glands 

 themselves. A further proof lies in the fact that the lactalbumin is not 

 identical with seralbumin; and lastly, as BuNGE 4 has shown, the mineral 

 bodies secreted by the milk are in quite different proportions from those 

 in the blood-serum. 



Little is known in regard to the formation and secretion of the specific 

 constituents of milk. The older theory, that the casein was produced 

 from the lactalbumin by the action of an enzyme, is incorrect, and prob- 

 ably originated from mistaking an alkali albuminate for casein. Better 

 founded is the theory that the casein originates from the protoplasm 

 of the gland-cells. According to BASCH'S researches, the casein is formed 

 in the mammary gland by the nucleic acid of the nucleus being set 

 free and uniting intra-alveolar with the transudated serum, thus form- 

 ing a nucleoalbumin, the casein. The untenableness of this view has 

 been shown by LOBISCH, and the investigations, of HILDEBRANDT 5 

 upon the proteolytic enzyme of the mammary gland, and the autolysis 



1 In regard to the literature on the action of various foods on woman's milk, see 

 Zalesky, " Ueber die Einwirkung der Nahrung auf die Zusammensetzung und Nahr- 

 haftigkeit der Frauenmilch," Berlin, klin. Wochenschr., 1888, which also contains the 

 literature on the importance of diet on the composition of other kinds of milk. In 

 regard to the extensive literature on the influence of various foods on the .milk pro- 

 duction of animals, see Konig, Chem. d. menschl. Nahrungs und Genussmittel. 3. Aufl., 

 1, 298. See also Maly's Jahresber., 29-40, and Morgen, Beger and Fingerling, Landw. 

 Versuchsst., 61, and Raudnitz, Monatschr. f. Kinderheilk. 



2 Cited from Konig, 2, 235. 



3 Landwirt. Vers. St. 1911. 



4 Lehrbuch d. physiol. und pathol. Chem., 3. Aufl., 93. 



6 Basch, Jahrb. f. Kinderheilkunde, 1898; Hildebrandt, Hofmeister's Beitrage, 5; 

 Lobisch. ibid., 8. 



