THE BACTERIOPHAGE IN DISEASE 



179 



phage active for the Shiga organism (+), extremely active for 

 B. coli (+ + + +), and but very slightly active for the dysentery 

 bacillus found in the patient f-f ). Against this last bacillus the 

 virulence increased during the course of the three following days, 

 reached its maximum activity (+ + ++), fell away somewhat 

 (++), and then definitely regained its full virulence (+ + + +) 

 These fluctuations in virulence were reflected in the condition 

 of the patient. At the end of convalescence there remained only 

 a slight activity (+) of the bacteriophage against B. coli. 



Day of the Disease 



^2 )H 



FIG. 3. VICTOR KER (6 years) DYSENTERY (SHIGA) 



f B. dysenteriae from the patient 



Virulence for \ B. dysenteriae, stock strain - - 



(B.coli 



Stools contained blood 



3. Victor Ker. ... (5 years, fig. 3). The dysentery was due to 

 the Shiga bacillus, was of moderate severity, and was contracted 

 by contact with the patient next discussed. When admitted to 

 the Hospital, on the third day of the disease, the intestinal bac- 

 teriophage already manifested an average virulence (++) for 

 the stock Shiga strain as well as for the strain isolated from the 

 patient. This virulence increased rapidly and maintained a 

 high value up to the time of complete convalescence (+H h). 

 It then abruptly disappeared. 



