256 THE BACTEEIOPHAGE AND ITS BEHAVIOR 



bacteriophagy with B. coli takes place in a manner identical to that with 

 B. dysenteriae. 



The resistant forms have been studied in particular by Bordet and 

 Ciuca, and by Gratia, and their papers have been analyzed at length 

 in the chapter dealing with resistance of the bacteria. They will not be 

 considered again here. 



8. The pneumohacillus of Friedldnder {Encapsulatus pneumoniae) 



Caublot^"^ having isolated a Friedlander bacillus from a blood culture 

 and having shown that it presented all of the characters of the species 

 attempted to find in the stools of the recovered patient (one month 

 after his discharge from the hospital) a bacteriophage virulent for the 

 organism isolated from the circulation. As a matter of fact he found a 

 bacteriophage having at first a moderate virulence but after a few pas- 

 sages causing complete bacteriophagy of a bouillon suspension. When 

 spread upon agar it gave characteristic plaques. Its virulence ex- 

 tended to other strains. The author states, without any further descrip- 

 tion, that the secondary colonies on agar are formed of atypical bacterial 

 elements. 



9 . The bacillus of Flacherie* 



Races of the bacteriophage virulent for this bacterium are frequently 

 encountered in the intestinal tracts of healthy worms found in infected 

 establishments (d'Herelle^^^. The activity of such a bacteriophage 

 has been found to be the same for 3 strains of the bacillus isolated from 

 the intestines of sick worms. Nevertheless I would classify this bac- 

 terium among the heterogeneous species for the tests have not been 

 sufficiently numerous with regard to the number of strains involved to 

 afiirm that it is homogeneous. The same may also be said with regard 

 to the bacillus of Friedlander. 



cording to the colonies, from a refractory state to a state of low resistance. From 

 the first isolation one may obtain, then, susceptible colonies but they are hardly 

 different in appearance from ultra-pure resistant colonies and in order to avoid 

 error it is always wise to make a series of subcultures in order that a possible 

 resistance may be lost. 



* Flacherie of silk worms 'does 'not seem to be a single disease. Several bac- 

 terial species appear to produce diseases manifesting the same characteristics. 

 The flacherie which I observed occurred in the silk worm establishments of Indo- 

 China. 



