98 BACTERIA AS ANTAGONISTS 



Phytomonas tumefacienSy even to the extent of suppressing vegetative 

 malformations brought about by the latter (69). Streftococcus cremoris 

 was active against Streftococcus lactis (979), Streftococcus mastidis 

 against S. lactis and Lactobacillus acidophilus^ and Streftococcus muco- 

 sus against P. festis (246). Rogers (765) reported an antagonistic effect 

 of S. lactis against L. bulgaricus; the active substance was thermostable 

 and was unable to pass through a bacterial filter (150, 178, 669, 676). 



Freudenreich (299) first emphasized the antagonistic action of 

 staphylococci against various bacteria. The list was later enlarged to in- 

 clude gram-positive acid-resisting forms (211), corynebacteria (52, 

 213, 214), and the plague organism (246). Some of these antagonists 

 were found to be able to lyse the dead cells of their own kind (351, 994- 

 996) as well as those of various other organisms. Gundel (370) isolated 

 from staphylococci an active lipoid which had bactericidal properties. A 

 water-soluble, alcohol-insoluble substance, said to be an enzyme capable 

 of bringing about the lysis of corynebacteria, was isolated from a strain 

 of staphylococcus (213, 214). 



Various micrococci possess strong antagonistic properties. Lode 

 (541 ) isolated a micrococcus which affected a variety of microorganisms 

 three or more centimeters away, the active substances being dialyzable. 

 An organism related to Micrococcus tetragenus and described as Micro- 

 coccus antibioticus (211) was found to possess a strong antagonistic ac- 

 tion against V . comma^ M. tuberculosisy E. tyfhosa. Ph. tumejacienSy 

 Br. melitensisy various spore-forming bacteria, numerous cocci, and 

 others (627). Diplococci exerted an antagonistic action against various 

 bacteria (541 ), including pyogenic staphylococci and streptococci in the 

 sputum (363), spore-formers, and gram-negative bacteria (447). They 

 produced, under aerobic conditions only, a filterable substance that was 

 heat resistant. 



The antagonistic action of pneumococci has definitely been estab- 

 lished (212, 244, 246, 368, 571, 634, 669, 733). The active substance 

 of these organisms was said (541) to be thermolabile, since it was de- 

 stroyed at 80° to 85° C. } it was produced only under aerobic conditions. 

 In reviewing the literature on the longevity of streptococci in symbiosis, 

 Holman (425) observed that many chances of error are inherent in 

 mixed cultures, particularly with closely similar organisms j pneumo- 



