AND ITS RELATION TO ANIMAL LIFE 37 



compounds found in man vary as they vary 

 in the vegetable and animal foods eaten. 



In Encyclopaedia Britannica, vol. xix. p. 50, 

 we find 



" The formation of organic nitrogenous sub- 

 stances may take place in any living cell, and, 

 unlike the formation of non-nitrogenous or- 

 ganic substance, it goes on quite independently 

 of the presence of chlorophyll and of the 

 action of light. But there is evidence to show 

 that in green plants it is especially in the cells 

 which contain the chlorophyll, that the pro- 

 cess goes on." 



The importance of this statement lies in 

 the fact that though nitrogenous substances 

 can be produced in chlorotic plants, still the 

 process is incomplete, and the quantity pro- 

 duced less than the normal. In other words, 

 the amount produced will have a certain ratio 

 to the chlorophyll, and hence to the iron. 



Hence animals living on chlorotic vegeta- 

 tion will not only be deficient in iron and 

 various carbon compounds, but also in nitro- 

 genous compounds or proteids. The fact 

 previously quoted, that proteids can only be 



