AND ITS RELATION TO ANIMAL LIFE 69 



and in mankind. Herein lies the suscepti- 

 bility or want of immunity in animal life to 

 disease. 



As haemoglobin is allied to the proteids and 

 a red modification of chlorophyll, it follows 

 that the haemoglobin of the animal varies 

 as the chlorophyll or chlorophyll products 

 vary in the plants eaten. In other words, 

 the carbohydrates, fats, and proteids of the 

 animal vary as the haemoglobin, which is 

 proved to vary by analysis ; see under Varia- 

 tion. 



It is recognized in most if not all bacterial 

 diseases that there is a deficiency of carbo- 

 hydrates, fats, and proteids, and that proteids 

 when present are fatal to these bacteria. 



Therefore as haemoglobin, to all intents and 

 purposes, is a proteid, it must be fatal to 

 pathogenic bacteria when present in normal 

 quantities. 



It is recognized that there is always a de- 

 ficiency of haemoglobin in these bacterial 

 diseases, but it is thought by some that the 

 bacteria cause the deficiency, that is, that the 

 bacteria eat up what is a poison to themselves, 

 which is, as far as I know, contrary to all the 



