BACTERIOPHAGE AS AN ANTIGEN 6^6 



bouillon, were implanted with a drop of a bouillon culture of B. dysen- 

 teriae Shiga. To the first of these tubes a drop of the antiserum- 

 bacteriophage mixture was added. The tube was thoroughly shaken, 

 and a drop was transferred to the second tube. In the same way, a 

 drop of the second tube was carried over to the third. In this way we 

 procured a series of three tubes, all having essentially the same number 

 of B. dysenteriae together with decreasing concentrations of the anti- 

 serum-bacteriophage mixture. The tubes were incubated at 37°C. 

 for 24 hours. Normal cultures of Shiga bacilli developed in the three 

 bouillon tubes and plantings made from them on agar also yielded 

 normal cultures. These results would indicate that the bacteriophage 

 had been destroyed. But the experiment was continued further; the 

 tubes were returned to the incubator, and after a second incubation for 

 24 hours it was found that in the first tube of the series a dissolution 

 of the bacteria had commenced. Furthermore, transfers from this 

 tube to agar remained sterile. Tubes 2 and 3 of the series still showed 

 a normal culture of B. dysenteriae at this time, but after incubation for 

 a further 24 hours dissolution had taken place in both of these. Agar 

 cultures made from these tubes remained free of growth. 



The conclusion that the effect observed here is that of an inhibition 

 only has been questioned, the objection being based upon the obser- 

 vation that sometimes, with particularly active antisera and particu- 

 larly sensitive races of the bacteriophage, bacteriophagy never takes 

 place, even after several days, and that in such cases it is impossible, 

 even by repeated passages, to reveal the presence of the bacteriophage. 

 Hence, this proves that the bacteriophage is destroyed. 



But even if such antisera exist, which may be possible, it does not 

 alter the significance of the experiment reported above. For this 

 experiment* shows unquestionably that after 24 hours there was a 

 complete inhibition, for no plaques appeared on the agar transfers, 

 even those made from the first tube where the number of corpuscles 

 was very considerable. And it is just as certain that on the following 

 day bacteriophagy was effected, and the spreading made on agar re- 

 mained sterile. There was, therefore, an inhibition, with a later 

 reactivation. In what way could this take place? 



Prausnitz has demonstrated that in a bacteriophage suspension 

 certain of the corpuscles are endowed with a very definite resistance, 

 and that the number of these sero-resistant corpuscles is the greater 

 when the quantity of antiserum added is small. This suggests the 



* I have repeated this experiment since these results were first published. 



