BACTEKIOPHAGOUS ULTBAMICROBE 



129 



The complement is fresh guinea pig serum, titrated. 

 The hemolytic system is the usual anti-sheep system. 



By itself, the lysin does not fix complement, on the contrary, as 

 shown by tube 6, it rather activates hemolysis. There is, there- 

 fore, an antibody associated with the lysin which fixes the com- 

 plement. 



It is difficult to reach a conclusion regarding this curious ex- 

 periment. Later investigations will show that there is a relation 

 between the amboceptor of Bordet and the lysin of the 

 bacteriophage, since it acts as two different principles, acting in 

 an identical manner, in so far as complement fixation is concerned. 



All of these experiments show that the bacteriophagous ultra- 

 microbe secretes a principle, precipitable by alcohol, resisting a 

 temperature of 58C., and persisting for several months in the 

 cultures of the bacteriophage. This principle, aside from its 

 solvent action, exercises a powerful opsonic action upon the bac- 

 teria for which the ultramicrobe from which it is derived possesses 

 a virulence. The opsonic activity appears proportional to the 

 virulence of the bacteriophage for the bacterium under consid- 

 eration. Bacteria which have acquired a resistance to the bac- 

 teriophage are equally resistant to phagocytosis. In addition, 

 from another viewpoint, we will see that they possess an increased 

 virulence. 



