SPORE-FORMING BACTERIA 89 



clarified. The lysed solutions of pneumococcus prepared by the use of 

 the filtrate of B. subtilis could be used for purposes of vaccination. In 

 this connection, Nicolle spoke of the work of Metchnikoff who had 

 proved, in 1897, that organisms belonging to the B. subtilis group are 

 capable of destroying various bacterial toxins. 



Rosenthal (806) isolated, from soil and from fecal matter, facultative 

 thermophilic antagonistic bacteria belonging to the B. mesentericus 

 group capable of dissolving both living and dead bacteria. The simul- 

 taneous growth of the antagonist with V. comma and other bacteria 

 brought about the clarification of the culture of the latter in about 5 or 

 6 days. These bacteriolytic organisms were designated as "lysobacteria." 

 It was recognized that the action of antagonists is different from that of 

 phage in several respects: (a) the filtrate of the antagonist is active 

 against other bacteria j (b) both living and dead cultures of bacteria are 

 dissolved J (c) antagonistic action is not so specific as that of phage j (d) 

 races of E. coli resistant to phage are dissolved by the filtrate of the an- 

 tagonist. The active substance was believed to be of the nature of an 

 enzyme. Friedlander's bacillus was not acted upon, possibly because of 

 the formation of a pellicle by the bacillus. The active substance was 

 formed in 4 to 5 days but increased in activity after 2 to 3 weeks. It was 

 essential that a surface pellicle of the organism be maintained. Sub- 

 merged growth was less favorable. Fresh filtrates had the greatest ac- 

 tivity, the property being lost after storage for 3 months. The substance 

 was thermolabile, activity being destroyed at 70° C. The filtrate of an 

 organism dissolved by the action of the antagonist proved to be as ac- 

 tive as the filtrate of the culture of the antagonist. It acted injuriously 

 upon intestinal bacteria not only in vitro but also in vivo. 



Much and associates (664) isolated several strains of B. •mycoides 

 that possessed strong antagonistic properties. The active strains were 

 said to be found only rarely in nature. They gave a mesentericus-like 

 growth, producing a pellicle and no turbidity in bouillon. One strain 

 was able to lyse 20 species of bacteria, another acted upon 18, a third 

 on 12, and a fourth on only 7. Marked differences were shown to 

 exist in the degree of antagonistic activity of the different strains. 

 P. vulgaris, E. tyfhosa, and V. comma were lysed in 24-hour bouillon 

 cultures as a result of adding pieces of agar containing colonies of the 



