244 THE BACTERIOPHAGE AND ITS BEHAVIOK 



containing lactose, levulose, saccharose, and also glycerine remain 

 alkaline. After a month the lactose, saccharose and levulose media 

 remain alkaline. Secondary cultures, and also mixed cultures, give the 

 indol reaction but do not react on either neutral red or lead acetate. 

 The resistant bacilli are inagglutinable, have a high viability, and are 

 more virulent for man. In Part III of this monograph we will consider 

 a case of B. dysenteriae Hiss septicemia in which the bacillus was resistant 

 to the action of the bacteriophage (d'Herelle^-^). 



Races of the bacteriophage virulent for B. dysenteriae Hiss have been 

 isolated from the intestinal contents of dysentery convalescents (d'Her- 

 elle^^"). They may be encountered under the same conditions as are 

 those races virulent for the Shiga bacillus. 



3. B. dysenteriae Flexner (Eberthella paradysenteriae) 



Races of the bacteriophage virulent for B. dysenteriae Flexner may 

 frequently be encountered under the conditions noted for the preceding. 



All of the races which I have isolated were active for certain strains 

 of B. coli; although with some, activity for other varieties of dysentery 

 baciUi was lacking. 



With reference to the bacteriophage, Flexner bacilli constitute a 

 homogeneous species. Resistant bacilli ferment glucose, levulose, 

 maltose, and mannite. They do not ferment lactose, do not blacken 

 lead acetate in an agar medium, and do not react on neutral red. They 

 form indol. They are inagglutinable by a specific serum and possess 

 a high viability. 



The atypical character of certain strains of B. dysenteriae when 

 freshly isolated from the organism may surely be ascribed to their 

 resistance to the bacteriophage. Elsewhere we will consider a typical 

 case. Furthermore, this observation is of general significance, applica- 

 ble not to dysentery bacilli alone (d'Herelle^^O- 



A Flexner-bacteriophage was isolated for the first time from the 

 stools of dysentery convalescents (d'Herelle^^"). 



4. Different intestinal bacilli (para- or pseudo-dysentery organisms) 



In cases of enteritis, bacilli may often be found which do not present 

 all of the distinguishing characters of B. dysenteriae, B. typhosus, or the 

 paratyphoids. Some of these strains may deviate from the descriptions 

 a great deal. Nevertheless, it would appear that they may be the cause 

 of the disease. 



