548 THE BACTERIOPHAGE AND ITS BEHAVIOR 



obtain a maximal virulence as I have defined it (complete and permanent 

 dissolution of normal suspensions of 250 million bacilli per cubic centi- 

 meter) races of the bacteriophage with a very high virulence may be 

 used, but those less active should never be employed. To use, either 

 for prophylactic or for therapeutic purposes, races of the bacteriophage 

 of moderate or even strong virulence, is to decide in advance that suc- 

 cess or failure makes no particular difference. 



I should also add that it is indispensable, even though the race of 

 bacteriophage used is of maximum virulence and does not permit 

 secondary cultures to develop, to filter the suspensions to be used for 

 therapeutic purposes through a candle of known efficiency. 



In addition, and on this point of general apphcation it is impossible 

 to place too much emphasis, it is imperative to administer the suspen- 

 sion just as early in the course of the disease as is possible. Early in 

 the disease the bacteriophage has but one thing to do — to cause bac- 

 teriophagy, — and this is all that is required. Naturally, the bacterio- 

 phage is unable to cause even the slightest modification in organic 

 lesions which have already developed. And, inasmuch as the adminis- 

 tration of the bacteriophage is always harmless, even if the diagnosis is 

 later proved to have been erroneous, it should be used at once without 

 awaiting a confirmatory laboratory diagnosis. '^-^ 



As regards dysentery. Otto and Munter,^®^ ^nd later Davison, ^^^ re- 

 ported that their attempts at treating bacillary dysentery were complete 

 failures. It is only fair to say that these authors made their attempts 

 early in their study of bacteriophagy, without apparently having a 

 sufficient knowledge of the distinctive characteristics of the bacterio- 

 phage, and, indeed, since in both of these reports the conclusion is 

 reached that the active principle is a ferment derived from the bac- 

 terium, any idea of virulence could hardly have been within their con- 

 ception. They most certainly used bacteriophage races of weak viru- 

 lence, and the results could not be other than those which they ob- 

 tained. This hypothesis seems the more probable, in that it so happens 

 that da Costa Cruz passed through the same experience before he 

 obtained the very beautiful results which we have just noted Two 

 years prior to the publication of the report from which we have just 

 quoted, that is, at the beginning of his work on the subject of bacterio- 

 phagy, he attempted the treatment of dysentery with suspensions of the 

 bacteriophage, and he concluded that the therapeutic value was pre- 

 cisely zero, "quite the opposite to what d'Herelle assumed."* 



* In his paperi" he states that the results obtained in this first series of experi- 

 ments were completely negative, "despite the great activity of the bacteriophage 



