AND ITS RELATION TO ANIMAL LIFE 33 



by the chlorophyll, and the chlorophyll is 

 governed by the iron and nitrogen that plants 

 find available. 



Therefore other carbohydrates, fats, and 

 finally proteids must be controlled by the 

 chlorophyll food of the plant, and as animal 

 life obtains its proteid food already formed, 

 then it follows that the proteid food of animal 

 life must vary as the proteids in the food 

 eaten. That this variation is considerable I 

 shall show in the following chapter. 



Animal life, then, deficient in proteids, 

 through a corresponding deficiency in the food 

 eaten, becomes more or less devitalized, and 

 consequently more or less liable to various 

 bacterial diseases ; further, when the animal 

 contains these proteids in anything approach- 

 ing normal quantities, the said animal is 

 immune to innumerable bacterial diseases, 

 as it is admitted that pathogenic bacteria can- 

 not live in the presence of proteids. (See 

 chapter on Immunity.) 



To show the value of carbon compounds in 

 food 



I remember some twenty years ago a flock 

 of ewes and lambs were driven past a country 



D 



