BACTERIA SUSCEPTIBLE TO BACTERIOPHAGY 259 



intraperitoneal injection of a culture of a diphtheria bacillus of low 

 toxicity. After 4 days he isolated from the intestinal contents a 

 bacteriophage which proved to be avirulent for the strain injected and 

 for three other toxic strains, but virulent for one atoxic strain. From 

 another guinea-pig, which died 40 hours after a subcutaneous injection 

 of a very toxic bacillus, he isolated a bacteriophage which was but 

 slightly active on 7 strains and inactive with 3, among which was the 

 strain injected. 



He procured on 3 different occasions races from the stools of an infant 

 convalescent of diphtheria. One of these filtrates contained a bacterio- 

 phage active for the strain isolated from the patient and for 7 other 

 strains, of which 3 were toxic. A second filtrate was active upon 5 

 strains and inactive with three others. The third filtrate was devoid 

 of all activity. 



He also isolated virulent bacteriophages from the peritoneal exudates 

 of guinea-pigs which had previously received an intraperitoneal injec- 

 tion of a diphtheria bacillus culture. Here the intestinal contents also 

 contained the bacteriophage. And, finally, attempting to isolate races 

 of the bacteriophage from old cultures of Corynebaderium diphtheriae 

 Blair found one strain which yielded a filtrate possessing a weak activity. 



The majority of the bacteriophages isolated caused bacteriophagy 

 also with different organisms of the colon-typhoid-dysentery group.* 



13. Nodule bacteria of the Legummosae {Rhizobium radicicolum) 



Gerretsen, Gryns, Sack, and Sohngen,-^ in a remarkable contribution 

 which has, it would appear, passed unnoticed, have described their 

 experiments upon bacteriophagy with Bacterium radicicolum. 



They worked upon nodules derived from the roots of clover, of lupin, 

 and of sarrandella. These nodules were first of all washed in a solution 

 of sublimate, 1 : 1000, and then they were passed successively through 



* Blair refers in his paper to a note of Botez^^ in which this author pretends 

 to have induced the formation of bacteriophages by the action of methyl violet 

 on cultures of various bacteria, Corynebacterium diphtheriae among others. I 

 do not know what Botez regards as bacteriophagy but in any case I am able to 

 affirm, on the basis of many experiments, that his conclusions are erroneous. As 

 a matter of fact several investigators, of whom Polettini Bruno^-^ and Tomaselli*^' 

 were among the first, have refuted the work of Botez and the latter has not sub- 

 stantiated his claim. It is extremely vmfortunate that such errors should pass 

 from paper to paper. It would seem to me that the first thing to do when one 

 encounters a contested point, and especially when the author does not support 

 this point, is to verify the finding before holding it established. 



