THE PERCENTAGE COMPOSITION OF COW'S MILK. 31 



The following figures are based on extensive experiments which 

 the author has carried out during a long period of years in different 

 places in Germany, as well as on other available German observa- 

 tions, and represent the average chemical composition of the day's 

 milk of large herds of cows (75 to 150), and the limits within which 

 the percentages of the separate constituents of such milk vary. 



Average. Limits of Variation. 



Water, 87'75 87-5 to 89-5 



Fat, 3-40 2-7 4-3 



Nitrogenous matter, ... 3*50 3'0 4'0 



Milk-sugar, 4-60 3'6 5-5 



Mineral matter ., '75 '6 ,, '9 



100-00 



The specific gravity of milk of this composition is 1 '031 65 at 

 15 C. The ratio of fat to nitrogenous substance is 100 : 103; 

 and the nutritive ratio 1 : 3"74. The composition of the total 

 solids is as follows: 



Fat, 27-75 



Nitrogenous matter, 28*57 



Milk-sugar, 37"56 



Mineral matter, 6*12 



100-00 



Under ordinary conditions, the milk-sugar is the largest con- 

 stituent of the milk solids. The nitrogenous matter is slightly 

 in excess of the fat. 



The average composition, according to the author's observations, of 

 the whole day's milk of comparatively large herds of cows in North 

 Germany, and of the countries bordering on the German Ocean, which 

 contain large-sized lowland cattle, is as follows : 



Specific gravity, 1-0314 



Water, 88-00 



Fat, 3-25 



Nitrogenous matter, ... ... ... 3 -40 



Milk-sugar, 4'60 



Mineral matter, 0*75 



100-00 

 By the term " total solids " is understood all the constituents of 



