14 Variations in Bacteria Caused by Change of Medium 



in every case to tubes of litmus-carbohydrate-serum-water, in which 

 the production of acid and gas was noted. The time of the appearance 

 of the phenomena in each case is recorded in Table V. 



Since the organisms were originally the same, variations observed in 

 the carbohydrate media are referred to changes of the bacteria 

 during growth in the eight media selected. From this Table it is seen that 

 great variations in the enzyme production of bacteria are produced 

 by appropriate changes in the environment. This is evidenced by the 

 widely differing results obtained by the organism after becoming 

 accustomed to different metabolic conditions. The organism from 

 Medium I behaves precisely as a B. Coli Communior, while from 

 Media VI and VII it possesses almost the type characteristics 

 of a B. Coli Communis. Although bacteriologists have been 

 accustomed to regard them as distinct species, we have been able, 

 by the aid of fatty acids in the culture medium, to obtain what prac- 

 tically amounts to a transposition from one to the other. 



AGGLUTINABILITY 



In order to test variability, if any, in the agglutinability of the 

 organism after removal from the eight specified environments, sera were 

 prepared from rabbits injected with the organisms grown on Media 

 I, III, V, and VII. The sera were then used in producing aggluti- 

 nation of the organism grown on all the different media. The results 

 are given in Table VI. 



TABLE VI 



Agglutinated organism (B. Coli) grown on 



