.HUMAN MILK. 629 



water to 5 volumes and the addition of 60-80 cc. N/10 acetic acid for 

 each 100 cc. milk. The mixture is first cooled for 2-3 hours and then, 

 after shaking, warmed on the water-bath to 40 for a few minutes. 



Even after those differences are eliminated which depend on the imper- 

 fect analytical methods employed, the quantitative composition of woman's 

 milk is variable to such an extent that it is impossible to give any average 

 results. The numerous analyses, especially those made on a large number 

 of samples by PFEIFFER, ADRIANCE, CAMERER and SOLDNER/ have posi- 

 tively shown that woman's milk is essentially poorer in proteins but 

 richer in sugar than cow's milk. The quantity of protein varies between 

 10-20 p. m., often amounting to only 15-17 p. m. or less, and is dependent 

 upon the length of lactation (see below) . The quantity of fat also varies 

 considerably, but ordinarily amounts to 30-40 p. m. The quantity of 

 sugar should not be below 50 p. m., but may rise to even 80 p. m. About 

 60 p. m. may be considered as an average, but it should be borne in mind 

 that the quantity of sugar is also dependent upon the length of lactation, 

 as it increases with duration. The amount of mineral bodies varies 

 between 2 and 4 p. m. 



From a quantitative standpoint, the most essential differences between 

 woman's and cow's milk are the following: As compared with the quan- 

 tity of albumin, the quantity of casein is not only absolutely but also rela- 

 tively smaller in woman's milk than in cow's milk, while the latter is 

 poorer in milk-sugar. Human milk is richer in lecithin, at least relatively 

 to the amount of protein. BUROW found 0.49-0.58 p. m. lecithin in cow's 

 milk and 0.58 p. m. in woman's milk, which corresponds to 1.40 per cent 

 for the first milk and 3.05 per cent for the second, calculated on the 

 percentage of protein. NERKING and HAENSEL found as average for 

 lecithin in cow's milk 0.63 p. m. and in woman's milk 0.50 p. m. KOCH 

 found that both human milk and cow's milk contain lecithin as well as 

 cephalin: The total quantity of both bodies in human milk was 0.78 

 p. m. and in cow's milk 0.72-0.86 p. m. The quantity of nucleon is 

 greater in woman's milk. WITTMAACK claims that cow's milk contains 

 0.566 p. m. nucleon, and -woman's milk 1.24 p. m., and according to 

 VALENTI the quantity of nucleon in human milk is indeed still higher. 

 SIEGFRIED finds that the nucleon phosphorus amounts to 6.0 per cent of 

 the total phosphorus in cow's milk and 41.5 per cent in woman's milk, 

 and also that in human milk the phosphorus is almost all in organic com- 



1 Pfeiffer, Jahrb. f. Kinderheilkunde, 20, also Maly's Jahresber., 13; V. Adriance 

 and J. Adriance, A Clinical Report of the Chemical Examination, etc., Archives of 

 Pediatrics, 1897; Camerer and Soldner, Zeitschr. f. Biologic, 33 and 36. In regard 

 to the composition of woman's milk, see also Biel, Maly's Jahresber., 4; Christenn, 

 ibid., 7; Mendes de Leon, ibid., 12; Gerber, Bull. soc. chim.. 23; Tolmatscheff, Hoppe- 

 Seyler's Med.-chem. Untersuch., 272. 



