MICROBIAL ANTAGONISTS 223 



or to the variability of the antagonizing agent as regards strain specific- 

 ity and the production of the active antibacterial substance. 



MICROBIAL ANTAGONISTS AND DISEASE CONTROL 



In 1 885, Cantani treated a tubercular patient with a culture of a sapro- 

 phytic organism, designated as Bacterium termo; the results were 

 highly favorable (104). He expressed the hope that other infectious 

 diseases readily accessible and of a local nature could be effectively 

 treated with saprophytic bacteria which are antagonistic to the patho- 

 gens. Following this work of Cantani, Zageri ( 1009) inoculated S. "pyo- 

 genes into animals suffering from anthrax j the rise in temperature 

 caused by the streptococcus reduced the viability of the anthrax. The 

 growth of an antagonistic organism was found to change the environ- 

 mental conditions favorable to the pathogen, thus causing its attenua- 

 tion. These results received the immediate attention of other investi- 

 gators (226, 844). 



Gate and Papacostas (318) observed that mixed infections were usu- 

 ally mild, a phenomenon later confirmed. Mixed cultures of the Fried- 

 lander bacillus and of C. difhtheriae gradually gave a predominance of 

 the former on repeated transfer} the morphology of the diphtheria 

 organism changed toward a more homogeneous state on staining. The 

 use of culture filtrates gave no evidence that the diphtheria toxin was 

 neutralized by the antagonist, either in vivo or in vitro; however, when 

 the two organisms were grown together no toxin was formed, nor was 

 toxin produced when the filtrate of the culture of the antagonist was 

 used to grow C. difhtheriae. The therapeutic use of filtrates was, there- 

 fore, suggested. Lactic acid bacteria were also employed successfully 

 i^'T^G) in the treatment of diphtheria. 



By allowing an antagonist to act upon a disease-producing organism 

 that has previously been heated to 56° C, a hydrolyzate was obtained 

 which could be employed as a vaccine (347). Bezangon (53) treated 

 typhoid sufferers with a culture of E. typhosa lysed by means of Ps. 

 aeruginosa. Gratia (347) said, however, that this type of hydrolyzate 

 will bring about heat production, but the use of a preparation obtained 



