VARIATIONS IN MILK. 



227 



cows, or good cheese cows, as the case may be. Such variations are 

 likewise often popularly referred to peculiarities in the color of these ani- 

 mals ; and, indeed, there is a general impression of the same kind as re- 

 spects the milk of women, that that of fair women is inferior to that of 

 brunettes. L'Heritier, who has examined into this matter, selected two 

 females of the same age, 22 years, and caused them to adopt the same 

 diet and the same mode of life. The one was a blonde, the other a bru- 

 nette. The following table exhibits the most marked of his results 



Milk of Women of different Temperaments. (From UHeritierS) 



The average of the various analyses he made shows the same general re- 

 sult, though not so strikingly, the number being for the solid constitu- 

 ents, in the case of the blonde, 120, and for that of the brunette, 134. 



As would be expected, the constitution of the milk varies greatly with 

 the diet. Simon found that in the case of a very poor woman, influence of 

 who had been almost deprived of the necessaries of life, the diet on milk - 

 quantity of solid material was only 8.6 per cent. On giving her a nutri- 

 tious meat diet it rose to 11.9 per cent. Being again reduced, by cir- 

 cumstances, to the utmost destitution, the solid residue sank to 9.8 per 

 cent. ; and on once more being supplied with a nutritious meat diet, the 

 percentage rose to 12.6. These results illustrate in a striking manner, 

 as will be presently seen, the function of the mammary gland. Simon 

 also found, in this particular case, that the relative quantities of casein 

 and sugar do not greatly vary with these extreme dietary variations, but 

 that the absolute quantity of butter does. On the two occa- Qri in of the 

 sions of starvation, it was as low as 8 parts in 1000 of milk, casein and of 

 and on the two of full nutritious diet, it rose to 34 and 37 thebutter - 

 respectively. From this it seems to follow that while the amount of 

 butter in milk is determined by the quantity and quality of the food, the 

 amounts of casein and sugar are, to a considerable degree, independent 

 thereof, and hence I believe their origin is to be attributed to changes 

 taking place in the system, and that these substances are more immedi- 

 ately furnished from metamorphoses of its structures. 



The casein and the sugar are reciprocally related to each other, the 

 quantity of casein steadily increasing from the time of par- Relative uan 

 turition until a fixed proportion is attained. At parturition tity of casein 

 the quantity of sugar is at its maximum, a gradual decline a sugar ' 

 then occurring until its proportion likewise becomes nearly constant. 



