300 



THE BACTERIOPHAGE AND ITS BEHAVIOR 



To turn to the other aspect of the subject, namely, the resistance 

 of the bacteriophage corpuscle to cold, I am, insofar as I am aware, 

 the only one who has studied the question. While at the University 

 of Leiden I carried out at the Institute of Refrigeration a few experi- 

 ments on the effect of cold upon the bacteriophage. The results are 

 interesting.* 



The suspensions were enclosed in thick glass tubes sealed in the flame. 

 The tubes were then placed for 10 minutes in liquid air. In some in- 

 stances exposure to the cold was repeated several times. The essential 

 data obtained are given in table 29. 



All of these races of the bacteriophage were of maximum virulence; 

 control suspensions, inoculated with 0.001 cc. of an unfrozen filtrate, 

 underwent bacteriophagy, dissolution being complete and permanent. 



These experiments show, insofar as they go, that the young corpuscles 

 resist exposure to a temperature of about -180°C., while the older 

 corpuscles are destroyed. 



7. ACTION OF INORGANIC CHEMICAL SUBSTANCES 



The reports of those who have determined the effect of inorganic 

 chemical agents upon the bacteriophage will be merely summarized. 



Acids and bases. Eliava and Pozerski^^- found that a Shiga-bac- 

 teriophage was destroyed by standing for 24 hours in media with a pH 

 of below 2.5 or above 8.4. In these experiments the pH values were 



* These experiments were made but a short time before my departure from 

 Leiden, and I have not yet had an opportunity to repeat them. I present them, 

 therefore, subject to confirmation. Causes of error are so easily overlooked that 

 a single experiment of this type has but limited value. 



