COMPOSITION OF HUMAN MILK IN AUSTRALIA. 197 



after different periods of rest, were compared in the present 

 case, it was found that after half an hour the percentage 

 of fat was 3*07; after one hour it was 2*95, and after that 

 fluctuated irregularly. No definite relation between the 

 time of rest of the mammary gland and the percentage of 

 fat of the milk yielded is apparent, therefore, from these 

 results. 



10. Summary. 



1. Certain values of the percentages of constituents other 

 than fat of human milk of the first week post partum 

 occurred much more frequently than others. These values 

 were: — total solids, 12*8; solids not fat, 9*8; protein, 1*9; 

 Solids not fat and not protein, 7*6. 



2. There was no definite percentage of fat near which 

 the percentages in the majority of the samples lay, but 

 the results were fairly evenly distributed over the whole 

 range of values found. The average percentage of fat 

 was 3*14. 



3. The average percentage of fat increased from 2*84 

 to 4*13 during the first eleven days of suckling; the average 

 percentage of protein decreased from 3*30 to 1*69 during 

 the same period. 



4. The age of the woman, the number of pregnancies, 

 the volume of the sample, the time since the last with- 

 drawal of milk from the breast, and the breast from which 

 the sample was taken, appeared to have no distinct effect 

 on the composition of the milk examined. 



5. A new method for the estimation of protein in milk 

 has been described. 



In conclusion, I wish to express my thanks to Professor 

 Sir Thomas Anderson Stuart, in whose laboratory this work 

 was carried out, and to Dr. H. G. Chapman for his advice 

 and helpful suggestions. 



