CULTURAL CHARACTERISTICS 115 



non-specific poisons (ptomaines, bases, nitrites, acids, gases, 

 etc.); (d) production of specific poisons (toxins). 



ANTIBODY FORMATION. 



Bacteria cause the formation of specific "antibodies" when 

 properly introduced into animals. This must be considered 

 as a physiological activity, since it is by means of substances 

 produced within the bacterial cell that the body cells of 

 animals are stimulated to form antibodies. (See Chapters 

 XXVI-XXIX.) 



STAINING. 



The reaction of bacteria to various stains is dependent on 

 their physico-chemical structure and hence is a result of 

 physiological processes, but is best discussed separately 

 (Chapter XIX). 



CULTURAL CHARACTERISTICS. 



The same is true of the appearance and growth on different 

 culture media (Chapter XX). 



