OTHER BACTERIA 99 



cocci, for example, were found to be able to live for long periods to- 

 gether with nonhemolytic streptococci. Peculiar antagonistic relations 

 between pneumococci and staphylococci were also reported (15). Adap- 

 tive alterations could be expected in the growth of bacteria in mixed 

 cultures (31). Which of the two organisms antagonizes the other was 

 believed to depend frequently upon the numerical abundance of one or 

 the other (244). 



OTHER AEROBIC AND ANAEROBIC BACTERIA 



The antagonistic action of Klebsiella pneumoniae against B. anthracis 

 has been reported (216, 676, 823). Freudenreich (299) found that the 

 filtrate of this antagonist repressed the growth of a number of bacteria 

 including the diphtheria (52, 634) and plague (246) organisms. 



Other aerobic bacteria were found capable of exerting antagonistic 

 effects against one or more organisms, these effects varying considerably 

 in nature and intensity. It is sufficient to mention the action of P. vul- 

 garis against B. anthracis and P. festis (246, 898)5 of Ps. aviseftica 

 against B. anthracis (672) and E. tyfhosa (299) j of Bacterium lactis 

 aerogenes against B. anthracis (365, 367) and P. festis (246). B. an- 

 thracis is capable of iso-antagonism (781, 827) and of antagonizing cer- 

 tain other organisms, including E. tyfhosa and Bacterium acidi lactici 

 (299, 827). Certain Myxobacteriales have been shown (841) to be ca- 

 pable of bringing about the lysis of various plant-disease-producing bac- 

 teria j a thermostable lytic substance, passing through cellophane but 

 not through a Seitz filter, was obtained. Although certain bacteria like 

 Achromohacter lifolyticum were found capable of reducing the patho- 

 genicity of M. tuberculosis^ no active cell-free extract could be ob- 

 tained (82). 



The morphology of one bacterium may be considerably modified by 

 the presence of another. Living cultures of L. bulgaricus influenced the 

 variation of E. coli from the "S" to the "R" phase, inhibited develop- 

 ment of the organism, and even brought about its lysis. No active sub- 

 stance could be demonstrated j the lactic acid itself had only a limited 

 effect (11). Korolev (499) has shown that when a yellow sarcina was 

 added to solid media a stimulating effect was exerted on the growth of 



