THE GENERAL COMPOSITION OF MILK 



ii 



Sugar appears to have a remarkably constant percentage both 

 among different breeds and among individuals of the breed. 



The authors carried out numerous researches into the nature of 

 the fat, and concluded that no variations occurred in the melting- 

 point of the fat which could be attributed to the breed of the cow. 



Eckles has shown that yearly variations occur in the amount 

 of fat in cows' milk. 



It would appear that there are no data as to the differences 

 in composition of human milk, as a result of difference of race, 

 although such differences may quite likely exist. 



B. Variations in Composition due to the Period of Lactation. 



It is well known that the milk given in the early days after 

 parturition is different in quality from the milk of later periods ; 

 also that alterations occur upon the approach of cessation of 

 lactation, and owing to disease. 



All these points require consideration, and it will be convenient 

 to consider first of all the general trend of the changes occurring 

 as the period of lactation passes on ; then to consider the special 

 composition of the milk in the early days after parturition. The 

 question of disease will be dealt with briefly. 



The alterations in special constituents of the ash due to the 

 period of lactation will be dealt with under the appropriate headings. 



Human Milk. Comprehensive investigations were made by 

 Pfeiffer in 1895 and by Schlossmann in 1900 upon the alterations in 

 human milk due to the period of lactation. Pfeiffer's figures are 

 as follows : 



