l6 PLANT DISEASE 



quantity of oxygen and to give off the maximum 

 quantity of carbonic debris, or food for patho- 

 genic bacteria, at the same time storing up in 

 the system the maximum percentage of pro- 

 teids. Such an animal must be more immune 

 than one with a deficient haemoglobin, where 

 oxygen and iron are deficient and carbonic 

 debris in excess. 



In other words, the condition of immunity 

 will vary directly with the assimilation into the 

 system of normal food, and the degree of im- 

 munity will vary inversely with the amount of 

 chlorotic food consumed. 



In a later chapter I shall go more fully into 

 the variations in the quality of given food 

 products, as shown by chemical analysis, and 

 hope to make it clear that to these variations 

 are due in many cases the liability to contract 

 disease and the lack of power to resist its 

 effects which cause so many premature deaths. 



I venture to think, however, that I have said 

 enough to indicate the intimate relations ex- 

 isting between the animal and vegetable king- 

 doms, and to show that variations in the 

 vegetable world must produce variations in the 

 animal world, for which it provides food, and 



