MECHANISM OF PROTEIN HYDROLYSIS AND IMMUNIZATION 59 



regular routine of its internal chemical processes, that the excre- 

 tions of the other organisms are no longer noxious to it. If we 

 choose, we may say that the organism has developed autobodies 

 or antitoxins against the offending neighbor organism. Thus it 

 would appear that the production of such antibodies must be 

 one of the most fundamental and primordial of life processes. 

 It is a function that is retained throughout the history of all 

 descendants of the protozoan, even to the remotest cell of the 

 highest organism. 



The reason for this is not far to seek; for it is a familiar 

 axiom of the evolutionist that all life is a struggle; and it is 

 obvious that the developing organism must come constantly in 

 contact with other organisms. With each new one, the old 

 struggle must be renewed with slightly new aspects, and new 

 methods must be found to equalize the adverse conditions 

 introduced. 



As the organism evolves to a multi-cellular condition, and de- 

 velops the various members and organs that mark the higher 

 animals, it will pass constantly to new environments and come 

 in contact with new enemies. Every time it encounters a new 

 type of food, be it vegetable or animal, it will present a new 

 problem to its chemical laboratory of the digestive and the 

 assimilative system. And unless this chemical laboratory proves 

 adequate to the new task put upon it, the organism will die. 



It follows that every existing organism has been able to run 

 this gauntlet and to find a solution of the new problems pre- 

 sented to it. 



In other words, every existing organism has learned to digest 

 and assimilate a great variety of proteins ; developing mechanisms 

 for neutralizing their poisons, until foods that were toxic have 

 now become wholesome. 



In this view, it will be observed, there is no suggestion that 

 one kind of protein rather than another is poisonous. It is simply 

 that each specific type of protein is somewhat antagonistic to 

 organisms composed of any other type of protein. It is only a 

 cannibalistic protein diet that can be said to be intrinsically harm- 

 less. But cannibalism involves the penalty of probable race 

 extinction ; and so in the nature of things evolutionary all living 

 organisms have learned to feed on the protein of other races 

 of organisms, adapting their own metabolic processes until they 

 are able to deal effectively with the offending side-chains in the 

 foreign molecule. Such a process of adaptation requires time, 

 and we may take it for granted that foreign proteins are "whole- 

 some" to any given organism somewhat in proportion to the 

 length of time during which the ancestors of that organism have 

 been accustomed to ingest it. That any given protein food is 



