THE COMPOSITION OF MILK 699 



exerts no influence on the mammary gland. Stimulation of the nerves to the 

 gland produces vascular changes that increase or decrease the quantity of 

 secretion. Many observations have been noted in women, which show that 

 the secretion of milk is sharply influenced by, or even completely suppressed 

 by, nervous states. 



The Composition of Milk. Milk has a specific gravity of 1028 

 to 1034. Its fat is held in emulsion. Under the microscope, it is found that 

 the milk globules vary in size, the majority being from 2 to 3 p. in diameter. 

 The old view that they have an investing membrane of albuminous mate- 

 rial is now generally discarded. 



COMPOSITION OF COLOSTRUM (PFEIFFER). 



Proteids 5.71 



Fat i 2 . 04 



Sugar 3.74 



Salts 0.28 



Water 88.23 



100.00 



SALTS IN WOMAN'S MILK (ROTCH). 



Calcium phosphate 23.87 



Calcium silicate 1.27 



Calcium sulphate 2.25 



Calcium carbonate 2 . 85 



Magnesium carbonate 3-77 



Potassium carbonate 23 .47 



Potassium sulphate 8.33 



Potassium chloride 12 .05 



Sodium chloride 21 . 77 



Iron oxide and alumina -37 



100. oo 



In addition to the oil or butter fat, milk contains certain proteids, milk- 

 sugar, and several salts. Its percentage composition is given in the tables 

 appended. 



CHEMICAL COMPOSITION OF MI-LK. (AFTER FOSTER, HARRINGTON, et a/.) 



Human. Cow. Mare. Bitch. 



Water 87.30 87 90 76 



Solids 12.70 13 10 24 



Fats 4-oo 4-0 2.0 10.0 



Proteids i-S 4-Q 2.5 10.0 



Sugar 7-0 4-3 5- 



Salts.. o- 20 -7 -5 -5 



