BACTERIOPHAGY IN A FLUID MEDIUM 71 



sium chloride retards the process; that magnesium sulfate and the 

 phosphates of sodium and of potassium, in low concentrations, possess 

 a stimulating action, especially with races of the bacteriophage of but 

 weak potency. I have not observed these effects in bacteriophagy 

 with other bacterial species. This apparently warrants the conclusion 

 that when a salt, in small amounts, seems to exercise an inhibitory or 

 a stimulating effect, it is because it favors or interferes with the develop- 

 ment of the bacteria, rather than because it exerts any specific direct 

 effect upon the process of dissolution. 



Body fluids and other substances 



When added to a bacterium-bacteriophage mixture, substances 

 devoid of action upon the bacteria, have, in general, no effect upon the 

 phenomenon. Thus, the process is not modified, for example, by 

 normal serum, ascitic fluid, or urine (d'Herelle^^^). Bile is unques- 

 tionably inhibitory. 



Antiseptics 



Kabeshima^^^'^^'' has stated that the bacteriophagy of B. dysenteriae 

 occurs even in the presence of antiseptic substances, for example, in 

 media containing sodium fluoride or an excess of chloroform. If these 

 observations are correct, they are quite at variance with the results 

 which I had obtained. At my suggestion Bablet^' has repeated the 

 experiments of Kabeshima. From his (Bablet) experiments, very 

 carefully performed, and carried out as were those of Kabeshima upon 

 B. dysenteriae, it appears that in a bouillon medium containing 1 per 

 cent of sodium fluoride, the bacteriophage principle does not regenerate 

 for after three passages in such a medium it has completely disappeared. 

 Under such conditions, therefore, bacteriophagy does not take place. 



The results were the same in the medium containing chloroform. 



I have shown^-^ that bacteriophagy does not take place in media 

 saturated with essences of thyme or of cloves, even though in such 

 media the bacteria remain alive for at least 48 hours. 



Wolff and Janzen®-^ have reported that bacteriophagy is not accom- 

 plished in the presence of different antiseptics, such as optochin, eucu- 

 pin, vusin (these three substances being derivatives of quinin), chinosol 

 yatren, trypaflavine, rivanol, and malachite green, even if these sub- 

 stances are added in quantities so small that the bacteria are killed 

 only after an appreciable interval. Under these circumstances, al- 

 though bacteriophagy is lacking, the bacteriophage is not destroyed; 



