306 THE BACTERIOPHAGE AND ITS BEHAVIOR 



ment of corpuscles appeared to be more active. This is not beyond 

 reason, for we know, indeed, that very minute amounts of certain anti- 

 septic substances exercise a stimulating action upon the growth of 

 various species of bacteria. 



Brutsaert^"^ reports that the corpuscles lose their virulence in 4 per 

 cent solutions of quinine hydrochloride. Recovery of the lost viru- 

 lence was slow; in his experiments it was not restored to its initial titre 

 until after 20 to 22 passages. 



Glycerol. The bacteriophage is destroyed by pure undiluted glycerol 

 (d'Herelle and Bablet^"- ^2°). A mixture of 0.25 cc. of a bacteriophage 

 (Shiga) and 5 cc. of anhydrous glycerol becomes completely inactive 

 after 8 days if kept in sealed ampoules at a temperature of 37°C. 



Subsequent experiments have shown that the Staphylo-bacteriophage 

 behaves just as do races active for the Shiga bacillus. The change 

 brought about is a complete destruction, for it is impossible to restore 

 the lost virulence by passages. 



Proca^2 suspended a mixed culture of bacteriophage-5. coli from agar 

 in anhydrous glycerol and observed that after 24 hours the bacterio- 

 phage was destroyed. Transplants to bouillon gave normal cultures 

 of B. coli. This would indicate that the bacteriophage is more sensitive 

 to the action of glycerol than is the bacterium,* 



Brutsaert^^^ has also reported that the bacteriophage is destroyed by 

 anhydrous glycerol. 



In concluding this discussion of the effects of organic substances on 

 the bacteriophage it may be added that Tomaselli^^^ states that filtrates 

 of B. suhtilis have no effect upon the bacteriophage corpuscles, and that 

 lonesco-Mihaiesti^'"' has shown that the corpuscles are unaffected by 

 lecithin and cholesterol. 



9. VARIABILITY IN THE RESISTANCE OF THE BACTERIOPHAGE 



As first suggested by Otto, Munter and Winkler,^^® and later confirmed 

 by a number of authors (Bruynoghe and Brutsaert,"^ Watanabe ®^^ 

 Reichert^^") , not only each race of the bacteriophage, but even each 

 individual bacteriophage, behaves at different times in a different 

 manner toward harmful agents, either physical or chemical. This 

 individuahty does not stop even there, for with a bacteriophage which is 



* If this experiment of Proca is confirmed another method of purifying mixed 

 cultures will be available. 



