COLOSTRUM. 625 



The quantity of mineral bodies in 1000 parts of cow's milk is, according 

 to the analyses of SOLDNER, as follows: K 2 O 1.72, Na 2 O 0.51, CaO 1.98, 

 MgO 0.20, P 2 O 5 1.82 (after correction for the pseudonuclein) , Cl 0.98 

 grams. BUNGE * found 0.0035 gram Fe 2 3 . According to SOLDNER 

 the K, Na, and Cl are found in the same quantities in whole milk as in 

 milk-serum. Of the total phosphoric acid 36-56 per cent and of the lime 

 53-72 per cent is not in simple solution. A part of this lime is combined 

 with the casein ; the remainder is found united with the phosphoric acid 

 as a mixture of dicalcium and tricalcium phosphates which is kept dis- 

 solved or suspended by the casein. The bases are in excess of the mineral 

 acids in the milk -serum. The excess of the first is combined with organic 

 acids, which correspond to 2.5 p. m. citric acid (SOLDNER). 



The gases of the milk consist chiefly of CO 2 , besides a little N and 

 traces of O. PFLUGER 2 found 10 vols. per cent CO 2 and 0.6 vol. per cent 

 N calculated at C. and 760 mm. pressure. 



The variation in the composition of cow's milk depends on several 

 circumstances. 



The colostrum, or the milk which is secreted before calving and in the 

 iirst few days after, is yellowish, sometimes alkaline, but often acid, of 

 higher specific gravity, 1.046-1.080, and richer in solids than ordinary 

 milk. The colostrum contains, besides fat-globules, an abundance of 

 colostrum-corpuscles nucleated granular cells 0.005-0.025 mm. in 

 diameter with abundant fat-granules and fat-globules. The fat of colostrum 

 has a somewhat higher melting-point and is poorer in volatile fatty acids 

 than the fat from ordinary milk (NILSON 3 ) . The iodine equivalent of the 

 colostrum-fat is higher than that of milk-fat. The quantity of cholesterin 

 and lecithin is generally greater. The most apparent difference between 

 it and ordinary milk is that colostrum coagulates on heating to boiling 

 because of the absolutely and relatively greater quantities of globulin and 

 albumin that it contains. 4 The composition of colostrum varies consider- 

 ably. KONIG gives as average the following figures in 1000 parts: 



Water. Solids. Casein. Albumin and Globulin. Fat. Sugar. Salts. 



746.7 253.3 40.4 136.0 35.9 26.7 15.6 



The influence which food exercises upon the composition of milk will 

 be discussed in connection with the chemistry of the milk secretion. 



In the following table is given the average composition of skimmed milk and 

 certain other preparations of milk : 



Water Proteins. Fat. Sugar. Lactic Acid. Salts. 



Skimmedmilk 906.6 31.1 7.4 47.5 ... 7.4 



Cream 655.1 36.1 267.5 35.2 ... 6.1 



Buttermilk 902.7 40.6 9.3 37.3 3.4 6.7 



Whey 932 . 4 8.5 2.3 47 . 3.3 6.5 



1 Zeitschr. f. Biologie, 10. 2 Pfluger's Arch., 2. 3 See Maly's Jahresber., 21. 



4 See Sebelien, Maly's Jahresber., 18, and Tiemann, Zeitschr. f. physiol. Chem., 

 25. See also Simon, ibid., 33; Winterstein and Strickler, ibid., 47. 



