SUMMARY OF CHAPTER X 



EXPERIMENTAL DATA UPON THE NUTRITIVE VALUE OF RAW AND 

 BOILED MILK AS A FOOD FOR THE YOUNG OF DIFFERENT SPECIES 



THE utilisation of boiled milk, in contradistinction to raw milk, as 

 a food for infants and young animals has formed the subject of 

 much discussion and of a considerable amount of experimentation. 

 The experiments have been conducted upon a variety of animals, 

 and results have been obtained which aid in the general question 

 of the feeding of infants. At the same time there are many 

 difficulties connected with animal experimentation upon this 

 subject, which must be afforded due consideration in forming 

 an estimate of the value of the work carried out. 



Difficulties in Connection with Animal Experiments. Although 

 it may appear that the simplest method of arriving at a satisfactory 

 conclusion in regard to the nutritive value of boiled milk, as opposed 

 to raw, would be by experimentation upon animals, certain circum- 

 stances arise which markedly vitiate the value of such work. It 

 has already been pointed out that the composition of milk of 

 different species varies very greatly. Hence in the first place, in 

 determining the animal to be used for the purpose of experi- 

 mentation and the kind of milk which is to be given, the com- 

 position of the milk should be considered so as to ensure, if 

 possible, some degree of similarity of composition between the 

 milk of the species itself and of the milk to be used for the 

 purpose of feeding. 



Serious practical difficulties, however, occur in obtaining samples 

 of the milk of certain species for use in feeding experiments. For 

 instance, certain species are extremely difficult to milk. They 

 appear to have the power to some extent of refusing to yield milk 

 if they so wish. 



It has been shown in Chap. II that in order to obtain an average 

 sample, especially an average fat sample, it is necessary that the 

 gland should be completely emptied and an estimation made of 

 the mixed sample. In the case of some animals this is impos- 

 sible, so that the estimations are probably not accurate. Even 

 if the precise composition were known it would be difficult to 



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