AND ITS RELATION TO ANIMAL LIFE 73 



various diseases, but if the public knew the 

 exact truth of the subject it would so simplify 

 it that every intelligent person would know all 

 that was required. 



As it is recognized that animal life must take 

 the proteids into its system already formed, 

 so the proteids must vary in the animal as 

 they vary in the vegetable food eaten, and as 

 the range of variation in plant food is very 

 great, so the range must be correspondingly 

 great in animal life. 



It is also recognized that proteids are fatal 

 to pathogenic bacteria, so that animal life rich 

 in proteids would be highly immune to patho- 

 genic bacteria, while animal life poor in pro- 

 teids would be very susceptible to disease. 



So that the difference between immunity 

 and susceptibility to disease is the difference 

 between a good supply and a poor supply of 

 proteids in the system, this depending, as I 

 have shown, upon the food and ultimately 

 upon the soil from which the necessary iron 

 and nitrogen must be obtained. 



As practical evidence it is well known in 

 South Africa that injections of bile rendered 

 cattle immune to rinderpest. 



