J. BRONFENBRENNER 553 



during life, this phage may adapt itself to a variety of bacteria. If, following an in- 

 fection, the adaptation of Bacteriophagum intestinale to an infecting bacterium takes 

 place quickly, the latter is destroyed before any symptoms of disease have appeared.' 

 If it responds to infection more slowly, the adaptation may not be completed early 

 enough to prevent the appearance of first symptoms of disease, but with the devel- 

 opment of "virulence," the Bacteriophagum intestinale may still check further prog- 

 ress of infection. The disease can thus develop fully only if the invading organism 

 remains unopposed by the phage. This occurs, for instance, when the invading bac- 

 terium happens to be resistant to phage or when it develops resistance in vivo dur- 

 ing the process of slow adaptation of phage. In such cases the "refractory" bacteria 

 may give rise to "formation of 'ultrabacteria' with an invasion of all the organs by 

 these filterable forms. "^ In isolated instances of infection, the phage carried by the 

 individual may totally fail to become adapted ("inertia of phage") to the invading 

 bacterium and thus permits unopposed development of infection. According to 

 D'Herelle, during epidemics this does not happen because "Frotobios bactcriophagus 

 is transmitted from one individual to another just as is the bacterium itself" and thus 

 "either the bacteriophage has acquired virulence (for the invading bacterium) in the 

 body of the individual who harbors it, or this individual has been 'contaminated' by 

 a bacteriophage which has acquired a virulence in another individual, "-^ In short, 

 according to D'Herelle,^ Hauduroy, Philibert, and others, the course of infection is 

 determined by the presence and the ready adaptability of phage. 



If the invading organism is susceptible to lysis and the phage acting upon it is 

 present, the prognosis of recovery is warranted. In cases ending with death, either 

 bacteria are found to be resistant or the phage fails to become adapted ("inertia").^ 

 On the basis of these findings, clinical use of bacteriophage for therapeutic purposes 

 has been attempted in a great variety of diseases. The results of these attempts are 

 evaluated by D'Herelle as follows: 



Phagotherapy represents a specific therapy for the bacillary dysentery and for staphy- 

 lococcus infections. The results obtained in a few cases of bubonic plague allow us to hope 

 that it is the same for this disease. With respect to the other infectious diseases, the results 

 obtained are encouraging, but as yet a perfect method of treatment has not been attained.^ 



These conclusions of D'Herelle and his collaborators have not been confirmed 

 in many instances. In the first place, several investigators were not able to establish 

 the relation between the presence of active bacteriophage and the progress of infec- 



'd'Herelle, F. : Compt. rend. Acad, de sc, 170, 72. 1920. 



^d'Herelle, F.: The Bacteriophage and Its Behavior, p. 478. 1926. 



sd'Herelle, F.: ibid., p. 508. 1926. 



4 "Every time one of the rats survived the infection consequent to the ingestion — and survival 

 is relatively frequent^I could demonstrate in the blood removed by heart puncture on the fourth 

 to sixth day after the infecting meal a bacteriophage virulent for the infecting bacterium" (d'Herelle, 

 F.: ibid., pp. 471-72. 1926). 



s Button, L. O.: loc. cit.; Stolz, J.: quoted from J.A.M.A., 85, 2002. 1925; de Jong, S., and 

 Hauduroy, P.: Bull. Soc. nied. des hop. de Paris, 49, 1561. 1925; Ilauduroy, P.: Fressc med., 33, 

 525- 1925- 



^d'Herelle, F.: Bacteriophage and Its Behavior, p. 577. 1296. 



