BACTERIA SUSCEPTIBLE TO BACTERIOPHAGY 257 



10. B. proteus (Proteus vulgaris) 



I have found two races of bacteriophage which were very virulent for 

 this organism at the time of isolation from the stools of two infants who 

 had died of infantile cholera.^^^ We will later say more with regard to 

 this point. When tested against a dozen strains of B. proteus only 3 

 were found to be susceptible and they were the same ones for each of 

 the two races. Two strains of B. proteus Xig were refractory. 



A bacteriophaged suspension, freed of bacilli by filtration, is extremely 



toxic for rabbits immediately after the dissolution of the bacilli. The 



subcutaneous injection of 0.5 cc. causes death within a few hours. 



After about 10 days the toxicity has diminished to almost nothing, 



and at this time the rabbit survives the intravenous injection of 2 cc. 

 (d'Herelle^^i)^ 



In the urine of a patient suffering from typhus fever Otto, Munter 

 and Winkler"^' found a bacteriophage virulent for B. typhosus, which, 

 after two passages, acquired a virulence for B. proteus Xig. In another 

 case, also of typhus fever, they found a race of the bacteriophage which, 

 after a few passages with the Flexner dysentery strain, was virulent for 

 B. dysenteriae Shiga, for the Hiss strain, and for B. proteus Zig. Un- 

 questionably these races had a virulence for the proteus strain when 

 they were isolated, and the virulence was enhanced for B. proteus 

 Xi9 simultaneously with that for B. typhosus in the first case and for 

 the dysentery bacilli in the second. 



Fejgin^ '"'■2 01.202 j^^g studied bacteriophagy and the bacterial forms 

 isolated from secondary cultures of B. proteus Xig. Unfortunately she 

 did not determine whether she was dealing with contaminated resistant 

 strains or with ultrapure strains, either resistant or susceptible. 



Fejgin first isolated a bacteriophage from an old culture of proteus 

 Xi9 obtained from Weil's laboratory. After about 15 passages it 

 brought about the dissolution of a suspension within 6 to 8 hours. The 

 filtrate contained from 3 to 6000 million bacteriophage corpuscles per 

 cubic centimeter. 



Plantings of secondary cultures on agar yielded five strains, with 

 which the colonies were respectively irregular, round, opaque, white, 

 and chromogenic. 



Among the white strains she observed two types: short rods with 

 very little motility and rod-shaped organisms that were very motile. 



Of three chromogenic cultures two were a bright yellow, 1 a canary- 

 yellow. All three strains liquefied gelatin slowly along the line of punc- 

 ture but they caused no reaction with sugars nor on milk, and did not 

 produce indol. 



