INORGANIC FOODS. 



369 



L. Hugonnenq l obtained quite similiar values : 



Except as regards the composition of the human infant and human 

 milk, we find by a comparison of the corresponding values that there is a 

 striking agreement between the ash of the young animal and that of the 

 milk. In the case of human beings, however, we do not find any such 

 agreement. Bunge explains this fact by the assumption that the ash 

 content of milk has not only the task of building up tissue, but also serves 

 in the preparation of the excreta, especially the urine. The more rapid 

 the growth of the suckling, the less apparent will be the influence of the 

 latter function. It is, therefore, in general not to be expected that the 

 percentage composition of the milk and that of the infant will agree so 

 closely in the case of human beings as with animals, such as dogs, rabbits, 

 and guinea pigs, which require the mother's milk for but a short time after 

 birth, but are soon placed upon a diet of green fodder. It is easy to see 

 that a milk corresponding closely to the chemical composition of the young 

 as regards the inorganic constituents will be more suitable for animals 

 which develop very rapidly, whereas with species which develop more 

 slowly, the building up of the separate tissues does not take place so uni- 

 formly and there are not so many changes taking place at the time when 

 the growing organism changes to another source of nourishment. 



We now come back to our first question: Does the suckling when it 

 abandons the mother's milk and passes to other food receive a sufficient 

 supply of inorganic salts? The following table gives a summary of the 

 amounts of inorganic substances contained in the more important foods : 2 



100 Parts by Weight of Dry Substance Contain : 



1 Compt. rend. 128, 1419 (1899). Cf. Cornelia de Lange: Z. Biol. 40, 526 (1900). 



2 Bunge: Z. Biol. 45, 532 (1902). 



