ANTAGONISTIC PROPERTIES 



117 



isolated at random from different soils, 49, or 20 per cent, of the cultures 

 were actively antagonistic} 57, or 23 per cent, showed some antagonistic 

 properties; and 138, or 57 per cent, possessed no antagonistic action at 

 all (Table 18). A somewhat similar distribution of antagonistic prop- 

 erties was observed among a group of well-identified species taken from 

 a type culture collection, embracing 161 pure strains. Only one of the 

 members of the genus Nocardia proved to be antagonistic ; only one of 

 the Micromonospora forms was active. Most of the antagonists were 

 found among the members of the genus Stre-ptomyces. These cultures 

 were also examined for bacteriolytic properties, living S. aureus being 



TABLE 15. ISOLATION OF ANTAGONISTIC ACTINOMYCETES 

 FROM VARIOUS SUBSTRATES 



From Waksman, Horning, Welsch, and Woodruff (958). 



Note. The organisms in group I were the most active antagonists, those in groups II and III had more limited 



antigonistic properties, and those in group IV showed no antibacterial effects with the methodg used. 



