Bacteriology. — "On the Bacteriophage and the Se //-pur I fi cation 

 of Water", by Prof. P. C. Flu. " 



(Communicated at the meeting of Dec. 30, 1922). 



In 1896 Hankin M reported that tlie water of various rivers in 

 India, i.a. the Yiimna and the Ganges possesses llie property of 

 rapidly destroyinj^ cliolera-vibriones. He was disposed lo ascribe this 

 property to a volatile snbstance, which he assumed to occur in the 

 water of the said rivers. 



Subsequent experimenters have demonstrated that all so-i-alled 

 surface-waters have (he faculty of exterminating microbes, notably 

 fortuitous pathogenic germs, at a rate depending on the nature of 

 the water and the temperature of the environment. 



Emmerich, who studied this phenomenon, the so-called selfpuri- 

 fication of water, believed that in this process (he part of germicide 

 must be assigned to protozoa (Rhizopods, Flagellates and Ciliates) 

 which occur in every surface-water. This view was adhered to by 

 nearly all inquirers, who had occupied themselves with the i)lienomenon. 



D'HÉRKi.i.K refers in his work "Le bacteriophage, son role dans 

 riminuriité" to the phenomenon observed by Hankin which he 

 thoroughly believes to be merely the effect of a bacteriophage pre- 

 sent in the water. 



Now, we know that bacteriophages are inactivated at a tempera- 

 ture above 75° C, and that Hankin could heat water of the said 

 rivers in a closed vessel (a sealed-np glass tube) for half an hour 

 up to 115° C, without depriving it of its bactericidal capacity. We 

 also know that, on heating up the Yuinna, and the Ganges-water 

 during the same interval and up to the same temperature (but in 

 an open vessel), it really lost its bactericidal capacity. 



Now, in view of these facts it will be difïicult to side with 

 d'HerelIjE, although we must admit at the same time that protozoal 

 action does not explain the phenomenon any better. 



Still, it cannot be denied that after d'Herei.le's significant disco- 

 very and after the establishment of the presence of bacteriophages 

 attacking various germs in all sorts of surface-waters, in seawater 

 and even in the effluent from septic-tanks and from oxidation-beds, 



1) Annales de I'Instituut Pasteur Vol. X pag. 175 and 511. 



