161 
ANTAGONISM ON B. FLUORESCENS AND B. TyPpHosus 
IN CULTURE. 
P. A. TETRAULT. 
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 « 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. 469 came from the Kral 
laboratories, Germany. No. 31 also came from the University of Chicago, 
*The Antagonism Exhibited by Certain Saprophytic Bacteria against the B. typhosus Gaffky. 
Jour. of Inf. Diseases. Nov. 5, 1914. 
11— 4966 
