BACTERIOPHAGE AS AN ANTIGEN 385 



teriophage had developed, — no antibacteriophagic property appeared 

 in the serum, but if they injected a mixed culture the serum became 

 antibacteriophagic. This might, indeed, have been predicted. I 

 have shown that the injection of rabbits with very old mixed cultures 

 (staphylococcus or Shiga) which had undergone several transplants, 

 yields antibacteriophagic sera although they are weak. 



The bacteriophage functions, therefore, as a specific antigen, an 

 antigen not found in the normal bacterium. Such is the conclusion 

 of these authors. 



According to Prausnitz^^^ the antibacteriophagic property is ther- 

 mostabile, resisting a temperature of 75°C. 



Otto, Munter and Winkler^^" found that different races of the bac- 

 teriophage do not possess identical antigenic properties, and they also 

 state that the higher the virulence of the bacteriophage, the stronger 

 is the antigenic property. The protocols of their experiments do not 

 seem to accord with this conclusion, as we will see later when we con- 

 sider the question of the specificity of antibacteriophagic sera. 



A very interesting observation made by these same authors, is that 

 if the antibacteriophagic serum is combined with bacteria which have 

 fixed the bacteriophage corpuscles, that is, when the serum is not added 

 until an hour after the bacteriophage is introduced into the bacterial 

 suspension, the corpuscles escape the action of the neutrahzing princi- 

 ple, for when spread on agar, no growth appears after incubation. 

 This is additional evidence that bacteriophagy can take place on a 

 solid medium.* 



These experiments of Otto, Munter and Winkler were confirmed 

 by Wagemans,''^^ who also reported that different bacteriophages do 

 not cause the appearance of "anti" properties having an equal neutral- 

 izing capacity. Certain of the antisera inhibited the action of the 

 homologous bacteriophage when they were mixed with the suspension 

 in a proportion of 1 to 1000, while others, under the same conditions, 

 appeared to have no neutralizing property at all.f They proved 

 that the nature of the animal inoculated contributed in no way to the 

 differences in the activity of the antisera, but that the variable results 



* This shows also that the bacteriophage corpuscles penetrate into the bacteria. 

 If they were only adherent to the surface it would be difficult to understand why 

 they should be protected against the action of the serum with which they are 

 bathed, 



t Comparable differences have been repeatedly observed with the bacteria 

 and their antisera; never with the toxins. 



