SPORE-FORMING BACTERIA 



93 



tagonistic effect upon many pathogenic bacteria, bringing about their 

 complete lysis. The time required for such lysis was 48 hours for gram- 

 positive cocci, 5 days for the typhoid and paratyphoid organisms, and 

 8 to 12 days for E. coli and M. tuberculosis (693). The action of B. 



TABLE 12. BIOCHEMICAL CHARACTERISTICS OF ACTIVE AND INACTIVE 

 STRAINS OF SPORE-FORMING SOIL BACTERIA 



subtilis upon various bacteria is also growth-inhibiting. This property is 

 due to the formation of one or more antibiotics which have been de- 

 scribed in the literature under several different names. 



Cultures of B. subtilis found (453) to have a high activity against 

 plant pathogenic bacteria yield an antibiotic that was designated (460) 

 subtilin. Other preparations designated by the same name (759) have a 

 strong bacteriostatic, bactericidal, and lytic effect upon a variety of bac- 

 teria, including B. anthracis, C. di-phtheriae, and Sh. dysenteriae; the 

 activity of the culture filtrate was about 4 to 1 6 units and there was a 

 marked parallelism between the antibacterial properties of the filtrate 

 and its proteolytic action. 



A water-soluble, nontoxic, relatively heat-stable compound was iso- 



