24 MILK AND ITS HYGIENIC RELATIONS 



Schlossmann also gives figures as below : 



The figures need no comment. They show the futility of fat 

 estimation unless a mixed sample of all the milk secreted at one 

 time is obtained, and the great importance from a nutritive stand- 

 point that the infant should obtain the end milk in the gland ; 

 otherwise it loses much of the fat. 



F. The Composition of Milk in Relation to Amount of Milk 

 Produced. The constancy in the percentage of certain constituents of 

 the milk, which has already been shown to be the case, suggests that 

 no fixed amount of these substances is secreted in the twenty-four 

 hours, but that the daily output varies roughly with the total milk 

 produced. Special attention has been devoted to this point by 

 Bamberg, who found that the differences in composition of human 

 milk were due to the individual women, and did not arise from 

 the secretion of varying amounts of milk. This holds good even 

 with a greatly increased milk production. 



Bamberg took samples before and after the child had been 

 fed, so as to obtain a medium sample. The analysis of a number 

 of samples showed that the percentage amount of protein, sugar, 

 and total ash are all independent of the amount of milk produced. 

 Bamberg also includes fat in the list, but this is not in accordance 

 with results obtained by other observers. 1 



G. The Effect of Different Intervals of Milking. The effect 

 produced on the amount of milk given by a wet-nurse by altering 

 the intervals of feeding, was studied by Helbich (2), and is dealt 

 with in Chap. VIII. 



Eckles and Shaw (3) carried out a study of the alterations in 

 composition of cows' milk due to a change in the intervals of 

 milking, and obtained the figures shown on p. 25. 



It is usually believed that the low fat-content frequently found 

 in the morning milk of cows is due to the longer interval elapsing 

 between the evening and morning, than between the morning and 

 evening milking. Eckles and Shaw's (3) figures, however, show 

 considerable variations in fat-content where, as throughout these 



1 Cp. below, pp. 42-43, on variation in fat-contents. 



