302 THE BACTERIOPHAGE AND ITS BEHAVIOR 



anhydrous sodium sulfate with a bacteriophage filtrate, and triturate 

 the mass so obtained, without causing a destruction of the corpuscles. 

 Bacteria also resist this treatment. 



Copper sulfate. A 1 per cent solution of this salt destroys the bac- 

 teriophage (Shiga) in 4 days.^^i 



Oxygen. Arloing, Langeron and Sempe^^ have reported that shaking 

 in the open air has no destructive effect upon the bacteriophage. 



8. ACTION OF ORGANIC COMPOUNDS 



Alcohol. Kabeshima has stated^^^ that the bacteriophage resists the 

 action of alcohol for several months, but I can not accept this statement 

 for I have found, as has everyone else who has worked on the subject, 

 that the corpuscles are destroyed in less than 48 hours by 90 per cent 

 alcohol. Indeed, de Poorter and Maisin^^^ report that in 94 per cent 

 alcohol, and even in 70 per cent, destruction occurs in less than 24 hours. 

 Appelmans'^^ states that a bacteriophage, originally active in a dilution 

 of 10"^", was active only to a dilution of 10~^ after 6 hours of contact 

 with 50 per cent alcohol. He found further that this titre remained 

 intact for at least 20 days. 



Watanabe'''^^ has observed a variation among different races as to their 

 resistance to alcohol, for according to his experiments some races were 

 already destroyed after 2 hours in 50 per cent alcohol, while other races, 

 a majority, were destroyed after contact for 20 hours. All of the races 

 with which he worked were destroyed by 75 per cent alcohol within a 

 period of 30 minutes. 



Once more it appears that there are differences in susceptibility, and 

 these variations must be associated with differences in virulence. 



Bronfenbrenner and Korb^^ have found that the bacteriophage was 

 rapidly destroyed by absolute alcohol at ordinary temperature, but that 

 it resisted for 5 or 6 days if held at 0°C. 



Considering all of these findings it appears that the results obtained 

 by the different workers are not strictly in accord, a fact unquestionably 

 referable to differences in the technic employed. The fact, as I have 

 shown, that a pure filtrate introduced into alcohol presents a much 

 greater resistance than does the same filtrate previously diluted with 

 water is suggestive. The reason for this difference is certainly the fact 

 that in the first case the protein materials (derived from the culture 

 medium and from the dissolved bacterial bodies) are energetically 

 coagulated, the bacteriophage corpuscles become enclosed in a mass of 

 material which protects them from the action of the alcohol. This 



