12 THE BACTERIOPHAGE AND ITS BEHAVIOR 



with the contents of a plague bubo, after becoming immediately turbid 

 through the development of B. pestis, became within the space of a 

 few hours absolutely cleared. The phenomenon was known in his 

 laboratory by the name of "B. pestis suicide." Unquestionably it 

 was due to the bacteriophage; in these particular cases B. pestis and 

 the bacteriophage being co-existent in the bubo developing toward 

 recovery. 



Pinoy has informed me that at the beginning of the late war, being 

 in Morocco engaged in the preparation of anti-typhoid vaccine, he 

 isolated a strain of B. paratyphosus A which presented definite plaques, 

 comparable in all respects to those which I have shown to be produced 

 by the bacteriophage. 



Also during the war, while stationed at Tiflis where he had charge 

 of the sanitary control of the water of the Koura river, Ehava observed 

 the following phenomenon. The water under examination was added 

 to a peptone-water medium. After incubation for a few hours a speci- 

 men removed from near the surface of the medium showed micro- 

 scopically an abundance of vibrios with a normal form. Transfers to 

 agar gave a light dull layer of growth which was microscopically com- 

 posed of a culture of the vibrios. Some 12 hours later, from both the 

 peptone water and the agar all trace of the vibrios had disappeared. 

 This observation was made several times, always giving a similar 

 result and it was impossible to obtain a culture of a vibrio which had 

 once commenced to develop and then disappeared a few hours later. 

 This phenomenon was inexphcable up to the time when he noted the 

 first communications dealing with the bacteriophage. 



It is, therefore, certain that a large number of bacteriologists have 

 accidentally demonstrated that such a strange phenomenon may take 

 place in a sohd or a liquid culture. But, because of the impossibihty 

 of reproducing the phenomenon at will, they have been unable to 

 pursue the study and they have not ventured to publish such things 

 since they appeared to be at variance with all known facts. 



It is, indeed, simply to the strangeness of the phenomenon of bac- 

 teriophagy, to its character of being what might be called paradoxical 

 that I owe the chance, so rare in contemporary science, of having been 

 able to perfect the study of such an extremely complex phenomenon, 

 to have had time to investigate its effects in nature, chiefly from the 

 point of view of the cure of infectious disease, to study their experi- 

 mental reproduction, even to make to this end a voyage and a year's 

 stay in Indo-China, there to more readily observe human and animal 



