548 SCIENCE PROGRESS 



curd-forming element of the milk-proteins, is present in great 

 excess ; moreover the delicate whey-proteins, which constitute 

 the bulk of the proteins in human milk, are only present in 

 relatively small amount in cows' milk. This will be clearly 

 seen from the proportions in the following table : 



Proteins in Human Milk and in Cows' Milk 



1-50 



3'5° 



Thus, in a given quantity of human milk the whey-proteins 

 will be twice as much as the caseinogen, while in cows' milk the 

 caseinogen will be two and a half times as much as the whey- 

 proteins. It must further be borne in mind that human milk is 

 not of constant composition. It varies with the individual mother 

 and with the age of the infant. Consequently, it is necessary, 

 in connection with substitute-feeding, to provide a method 

 which meets the varying requirements. 



The procedure carried out in the milk-laboratory of the 

 Infants Hospital illustrates all the essential factors and the 

 measures by means of which the special and varying require- 

 ments of the infant are met. 



The fundamental principle underlying the work of the milk- 

 laboratory is the adherence to the standard of human milk in 

 its natural condition. No methods of boiling, pasteurising 

 or otherwise cooking milk are allowed. All the sterilisation 

 that is effected is applied not to the milk but to the vessels 

 coming in contact with it. Some of the processes to be 

 described are rather more elaborate than may be necessary for 

 the average healthy infant ; but it must be remembered that 

 the hospital is dealing with infants who are critically ill and 

 that the dietetic adjustments for them need to be of the most 

 refined character. Nevertheless, the general principles apply 

 to the substitute-feeding of all infants. As soon as the milk is 

 received in the laboratory the cream is tested in order to deter- 

 mine the exact amount of fat it contains. This having been 

 ascertained, a standard cream is prepared by the addition of the 

 proper amount of fat-free milk. Whey is prepared from the 



