ADAPTATION OF ORGANISMS 339 



and the CYTOTOXINS which actually destroy the foreign cells. 

 Various specific antibodies may be naturally present in the 

 blood a part of the heritage so that an individual is 

 immune to certain diseases due to pathogenic organisms. 

 Or the antibodies may be produced in response to the para- 

 sites themselves, and the individual acquires immunity only 

 after undergoing the disease. Finally, immunity may be 

 artificially acquired by various means, such as VACCINATION, 

 which stimulate the production of antibodies so that the 

 individual is fore-armed, as it were, in the event of an infec- 

 tion. But the subject of immunity has become a science in 

 itself within the past few years a science which has as its 

 basis the exploitation of the marvelous power of adaptation 

 of protoplasm as exemplified in coping with disease-producing 

 parasites. 



C. INDIVIDUAL ADAPTABILITY 



We may now turn to a survey of the highest expression 

 of adaptation evolved by nature, which is revealed in rela- 

 tively simple form in the behavior of the lower organisms, 

 gains definiteness and content as we ascend the animal series, 

 and becomes the basis of the intelligence and all that the 

 mental life of Man involves. It is the adaptation which 

 renders Man essentially superior to adaptation enables 

 him to a large extent to control, instead of being controlled 

 by, his environment. "It seems that nature, after elaborat- 

 ing mechanisms to meet particular vicissitudes, has lumped 

 all other vicissitudes into one and made a means of meeting 

 them all" - the nervous mechanism. 



That organisms respond to environmental changes, we are 

 well aware. Life itself is the result of in fact, is a con- 

 tinuous flow of physico-chemical actions, interactions, and 

 reactions with the surroundings. But by the behavior of 



