COMPOSITION OF HUMAN MILK IN AUSTRALIA. 173- 



difficulty in collecting samples large enough for analysis 

 by this means, the use of the breast pump was resorted to r 

 and all of the samples except the first two or three were 

 collected with it. 



In the case of each sample of human milk the nurses 

 were instructed to record the following particulars : — 



1. Age of mother. 



2. Number of pregnancies. 



3. Age of child. 



4. Time of collection of sample. 



5. Time of last suckling. 



6. Breast from which sample was taken. 



The nurses were directed to obtain the whole sample 

 from one breast whenever possible, and to endeavour to 

 empty the breast completely. The samples of milk were 

 collected between 6 a.m. and 9 a.m.; the analyses were 

 begun at about 10 a.m. of the same morning, so that all the 

 estimations were made upon perfectly fresh milk. 



Methods of Analysis. — Determinations of density, total 

 solids, fat, and total protein, were made on the samples of 

 human milk obtained. The amounts of solids not fat, and 

 of solids not fat and not protein (chiefly milk-sugar) have 

 been calculated by difference. 



The densities of the milks were determined with a 

 pyknometer. The pyknometer used for the first twenty- 

 five samples had a volume of about 8*5 cc, but as the 

 quantities of milk obtained were occasionally smaller than 

 this, a pyknometer having a volume of only about 2*7 cc. 

 was used for the rest of the determinations. The levels of 

 the pyknometer were adjusted after it had hung in a water 

 thermostat for at least ten minutes; the densities given 

 are for a temperature of 25° O. Their values are given to 

 one part in 10,000. 



