PROPERTIES AND COMPOSITION OF MILK. 335 



COMPOSITION OF HUMAN MILK. 



Water 902-717 to 863-149 



Caseine (desiccated) 29-000 " 39-000 



Lactoproteine I'OOO " 2-770 



Albumin traces " 0-880 



f Palmitine 17-000 " 25-840 



Butter, 25 to 38 ) Oleine 7-500 " 11-400 



( Butyrine, caprine, caprome, caprilene etc. 0-500 " 0'760 



Sugar of milk (lactose) 37-000 " 49-000 



Sodium lactate (?) 0-420 " 0-450 



Sodium chloride 0-240 " 0-340 



Potassium chloride 1-440 " 1-830 



Sodium carbonate ! . . 0-053 " 0-056 



Calcium carbonate 0-069 " 0-070 



Calcium phosphate 2-310 " 3-440 



Magnesium phosphate 0-420 " 0-640 



Sodium phosphate 0-225 " 0*230 



Ferric phosphate (?) 0-032 " 0-070 



Sodium sulphate 0*074 " 0-075 



Potassium sulphate traces. 



1,000-000 1,000-000 



( Oxygen 1-29 } 



Gases in solution < Nitrogen 12-17 30 parts per 1,000 in volume. (Hoppe.) 



' Carbon dioxide. 16*54 ) 



The proportion of water in milk is subject to certain changes, but these 

 are not so considerable as might be expected from the great variations in 

 the entire quantity of the secretion. As regards the quantity of milk in the 

 twenty-four hours, the influence of drinks, even when nothing but pure water 

 is taken, is very marked ; and although the activity of the secretion is much 

 increased by fluid irigesta, the quality of the milk usually is not affected, and 

 the proportion of water to the solid matters remains about the same. 



Nitrogenized Constituents of Milk. Very little remains to be said con- 

 cerning the nitrogenized constituents of human milk, after what has been 

 stated in connection with alimentation. The different constituents of this 

 class undoubtedly have the same nutritive office and they appear to be iden- 

 tical in all varieties of milk, the only difference being in their relative pro- 

 portions. It is a matter of common experience, indeed, that the milk of 

 many of the lower animals will take the place of human milk, when prepared 

 so as to make the proportions of its different constituents approximate the 

 composition of the natural food of the child. A comparison of the composi- 

 tion of human milk and of cow's milk shows that the former is poorer in nitro- 

 genized matters and richer in butter and sugar ; and consequently, the upper 

 strata of cow's milk, properly sweetened and diluted with water, very nearly 

 represents the ordinary breast-milk. 



Caseine is by far the most important of the nitrogenized constituents of 

 milk, and it supplies nearly all of this kind of nutritive matter demanded by 

 the child. Lactoproteine, described by Millon and Commaille, is not so well 

 defined, and albumin exists in the milk in very small quantity. 



