THE COMPOSITION OF MILK 735 



Tne secretion of the first few days is called the colostrum. It contains a 

 larger per cent, of solids, has the large granular colostral corpuscles, is more 

 alkaline than ordinary milk, and has a specific gravity of 1040 to 1046. 



The mammary glands have been isolated from the nervous system to 

 determine whether or not the association in time between their changes and 

 the changes in the uterus were of a nervous nature. The isolated mammas 

 develop and begin lactation at parturition as in the normal. It would seem 

 that here, too, there is some special form of stimulation through the medium 

 of the blood. Yet one must not draw the conclusion that the nervous system 

 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/z in diameter. 

 The old view that they have an investing membrane of albuminous material 

 is now generally discarded. 



COMPOSITION OF COLOSTRUM (PFEIFFER). 



Proteins 5-7 1 



Fat 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 I2 -05 



Sodium chloride . . . 21.77 



Iron oxide and alumina 3 7 



100.00 



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

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

 appended. 



