BACTERIOPHAGY IN A FLUID MEDIUM 59 



We may here state what has been demonstrated in this connection 

 up to the present time for different bacteria when subjected to the 

 action of homologous races of the bacteriophage. 



B. typhosus. Bacteriophagy takes place at temperatures up to 

 41°C. ; it is even more active at this temperature than at 37° (Kuttner^^^). 

 The phenomenon does not take place at 45°C. (Kuttner^®^). 



B. dysenteriae. A complete dissolution of dysentery bacilli takes 

 place at temperatures between 8° and 41°C. (d'Herelle^^O, but the time 

 required for the end result to be attained is very variable. 



Three tubes, each containing a normal suspension of Shiga bacilli* 

 are inoculated with 10~^ cc. of a filtrate containing the bacteriophage. 

 These tubes are placed, one at 8°C., one at 22°, and the third at 37°. 

 Subsequent examination shows that in the suspension held at 8° the 

 bacteria have been completely dissolved after 16 days. In the one 

 held at 22° dissolution is complete after 25 hours. In the one kept at 

 37° the dissolution is complete after 13 hours, 



B. pestis. Two races of the bacteriophage have been tested against 

 a single strain of B. pestis. In both cases the maximum temperature 

 limit for complete dissolution was 41°, with the optimum temperature 

 at 37°C . 



Staphylococcus. Against a single strain of Staphylococcus aureus 

 two different races of staphylococcus bacteriophage were tested; 

 the first, race H, caused a complete dissolution at temperatures up to 

 43°C., the other, race B, only up to 41°. The optimum for the first 

 was at about 32°, for the second at about 3G°C. 



B. coli. Doerr and Griiningeri^^ have reported that bacteriophagy 

 of B. coli does not take place at 43°, despite the fact that the strain 

 of B. coli used by them developed at this temperature. It seemed, 

 indeed, from their experiments that the bacteriophage, acting under 

 such conditions of temperature, totally disappeared from the medium 

 at the end of 5 to 7 hours. In attempting to verify this experiment, 

 the results of which appeared to be rather unusual, I obtained entirely 

 different results. Details of these experiments follow. The B. coli, 

 strain H, was isolated from a case of cystitis. The bacteriophage, 



* When, in the description of an experiment the volume of a suspension is not 

 stated, it should always be understood to be 10 cc. In the same way, in order to 

 avoid repetitions such as would make the explanation unnecessarily long, unless 

 indicated to the contrarj^, the culture medium is a beef bouillon (400 grams of 

 muscle extracted per liter) with 1 per cent of peptone and 0.8 per cent of salt. 

 The reaction is adjusted to a pH of 7.8. 



