161 



Antagonism on B. Fluorescens and B. Typhosus 

 in Culture. 



P. A. Tetratjlt. 



It is a fact long established that when two organisms live together 

 in close relationship, the association will be one of tolerance, of mutual 

 benefit or of one-sided injury. The term antagonism as used in this paper 

 has more the meaning of one-sided injury. The phenomenon, for the bac- 

 teria, was recognized as far back as 1888 when Freudenreich and Garre, 

 working independently, demonstrated specific antagonisms between given 

 bacterial forms. The last named worked especially with B. typhosus. It 

 was found that the typhoid organism did not thrive in a medium where 

 certain other bacteria had previously grown ; in other words, the cell 

 secretions were toxic for B. typhosus. 



W. D. Frost,* working on this same problem, discusses a number of 

 theories advanced to account for this phenomenon. 



One theory is that of the exhaustion of the food supply. All the 

 available food has been extracted from the medium by the first organism 

 growing on it. This was controverted by Olitzky by demonstrating that 

 Micrococcus aureus would grow on a medium which had nourished a 

 previous crop of bacteria but which did not permit the growth of B. 

 typhosus. 



Another theory was that of enzyme action. This, Frost says, could 

 not hold in this case because enzymes are colloidal in nature and could 

 not pass through a collodion membrane. 



A history and comparison of the different cultures used in my work 

 is given below. 



All the cultures came from The Museum of Natural History, New 

 York. No. 29 was obtained originally from the University of Chicago 

 and was isolated from the swimming pool. No. 409 came from the Krai 

 laboratories, Germany. No. 31 also came from the University of Chicago, 



"The Antagonism Exhibited by Certain Saprophytic Bacteria against the 6 . typhosus Gaffhy. 

 Jour, of Inf. Diseases. Nov. 5, 1914. 



11— 4'JGG 



