i 2 8 THE CHEMISTRY OF THE TISSUES AND ORGANS. 



Normal human milk. The following table gives some of the 

 principal analyses that have been published : 



The most constant feature in these analyses is the relatively low 

 percentage of proteids and high percentage of sugar. 



Among other constituents of human milk are, 0*32 per cent, of 

 cholesterin (Tolmatscheff), O05 of citric acid, 10 and 078 n of unknown 

 extractives; the last are more abundant in the colostrum, and less 

 abundant in cows' milk (Soldner and Camerer). 



Variations in the composition of the milk occur with the stages of lactation, 12 

 in the milk from the two breasts and between the first and last portions of 

 the milking, 13 with the complexion 14 (Vernois and Becquerel questioned 

 by Tolmatscheff), with the age of the individual (Pfeiffer), and with menstrua- 

 tion (Vernois and Becquerel). The nature and quality of the food have a 

 considerable influence on the quality of the milk. 15 



The salts of human milk are thus given by Bunge 16 in parts per 1000. 



K 9 



CaO 

 MgO 



A. 



0-780 

 0-232 

 0-328 

 0-064 



B. 



0-703 

 0-257 

 0-343 

 0-065 



Fe 9 3 



A. 



0-004 

 0-473 

 0-438 



B. 



0-006 

 0-469 

 0-445 



1 Jahresb. ii. d. Fortschr. d. Thier-Chem., Wiesbaden, 1874, S. 168. 



2 "Med. Chem. Untersuch.," Bd. ii. S. 272. 



3 Bull. soc. chim., Paris, tome xxiii. 4 Diss., Erlangen, 1877. 



5 Jahrb.f. Kinderh., Leipzig, Bd. xx. 6 Diss., Heidelberg, 1881. 



7 Diss., Strassburg, 1876. 8 Ztschr.f. EioL, Mlinchen, 1896, Bd. xxxiii. S. 43. 



9 Arch.f. d. ges. Physiol., Bonn, Bd. Ivi. S. 558. 



10 The presence of citric acid has also been noticed by Scheibe, Landw. Versuchs. Stat., 

 Berlin, Bd. xxxix. 



11 J. Munk (Virchow's Archiv, Bd. cxxxiv. S. 501) gives the proportion of extractive 

 nitrogen to total nitrogen as 1:11 in human and 1:16 in cows' milk. 



12 Pfeiffer, loc. cit. ; Vernois and Becquerel, Compt. rend. A cad. d. sc., Paris, tome xxxvi. 

 p. 188. 



13 Sourdat, ibid.> tome Ixxi. ; Brummer, Arch.f. d. ges. Physiol., Bonn, Bd. vii. 



14 1'Heritier, "Traite de chim. pathol.," Paris, 1842. 



15 Decaisne, Gaz. med. de Paris, 1871, p. 317. These are very interesting observations 

 made during the siege of Paris. Other work on the influence of food on milk is that by 

 Szubotin, Centralbl. f. d. med. Wissensch., Berlin, 1866, S. 337, and by Commaille, quoted 

 by Konig, "Chem. d. menschl. Nahrungs. u. Genussmittel, " Bd. ii. S. 235. The question 

 of the influence of diseases and drugs will be found discussed in works on Therapeutics 

 and Pathology. 16 Ztsclir. f. JSioL, Mimchen, Bd. x. 



