410 THE GLASDULAR ORGANS. 



Skimmed milk is, of course, specifically heavier than full milk, 

 and a higher specific gravity is accordingly also noted in milk which 

 is poor in fat than in rich milk. 



Reaction. Woman's milk and that of most herbivorous animals 

 is uniformly amphoteric, owing to the presence of diacid and inon- 

 acid phosphates in association with the calcium compound of casein. 

 The relative values of the acid and basic components in cows 7 milk 

 and human milk are given below in terms of decinormal sodium 

 hydrate and sulphuric acid solution. The figures have reference to 

 100 c.c. of milk and are average values (Courant): 



T 1 oH 2 S0 4 Ratio. 

 Human milk ............. 10.8 c.c. 3.6 c c. 3:1 



Cows' milk .............. 41.0 c.c. 19.5 c.c. 2:1 



Human milk is thus relatively more alkaline than cows' milk, but 

 is absolutely both less alkaline and less acid. 



Mares' milk is alkaline and that of the carnivorous animals acid. 



Chemical Composition. A general idea of the chemical composi- 

 tion of the milk of different animals and of woman may be formed 

 from the following analyses, which are taken from Konig, Gorup- 

 Besanez, Hoppe-Seyler, and others : 



Human. Cow. 



Water ................ 872.40-892.90 842.8-860.0 



Solids ................ 108.00-127.60 140.0-157.2 



Albumins (total) ........ 16.13- 36.91 33.0- 43.2 



Albumin (proper) ........ 3.50- 9.91 1.2- 2.8 



Casein ............. 12.80- 27.00 30.2- 42.0 



Fats .............. 25.60- 43.20 40.0- 64.7 



Lactose ............. 53.90- 60.90 43.4- 50.0 



Salts .............. 1.650- 4.200 6.3-* 7.1 



A survey of this table thus shows that human milk contains a 

 smaller amount of albumins and fats but more lactose than cows 7 

 milk. 



In addition to the above components the milk contains traces of 

 urea, kreatin, kreatinin, hypoxanthin, cholesterin, animal gum, and, 

 curiously enough, citric acid, which is present as a calcium salt to 

 the extent of from 0.18 to 0.25 per cent. Besides these, we find a 

 small amount of lecithins and a yellow lipochrome. 



Goat. Sheep. Mare. Ass. Dog. Cat. 



Water ...... 869.1 835.0 900.6 900.0 754.4 816.3 



Solids ...... 130.9 165.0 99.4 100.0 245.6 183.7 



Albumins . . 36.9 57.4 18.9 21.0 99.1 90.8 



Fats .... 40.9 61.4 10.9 13.0 95.7 33.3 



Lactose . . . 44.o 39.6 66.5 63.0 31.9 49.1 



Salts .... 8.6 6.6 3.1 3.0 7.3 5.8 



Analysis of the inorganic components of human milk has given 

 the following results (Bunge) : the figures of the first column were 

 obtained at a time when but little sodium chloride was ingested, 

 while those of the second column were gotten while the woman 

 ingested 30 grammes a day (the total ash is calculated as 1000. parts 

 by weight) : 



