552 THE BACTERIOPHAGE 



ary cultures, that they represent the individuals which aged before they under- 

 went complete lysis, seems inadequate. Even very young subcultures from the 

 secondary growths are resistant to lysis. It is also difficult to explain, on this basis, 

 why a given secondary growth will resist the action of the bacteriophage which caused 

 its selection, but will undergo lysis by another closely related phage. 



Equally inadequate is the attempt to ascribe the resistance in general to slime or 

 mucus production. Although some cultures under the influence of phage give rise to 

 slime-producing variants which resist the phage action, and although this phenomenon 

 has been considered as a specific protective action on the part of bacteria,' slime pro- 

 duction seems apart from the usual phenomena of resistance to phage, particularly be- 

 cause such cultures are resistant to all lytic agents without discrimination.^ This fact, 

 together with the evidence that removal of slime, by bile for instance, renders the 

 bacteria both agglutinable and susceptible to lysis,^ seems to indicate that this type 

 of variants differs from usual resistants and owes its properties entirely to the mechan- 

 ical protection of the slime. Furthermore, since only a few species of bacteria give 

 rise to slime-producing variants, this phenomenon cannot explain the mechanism of 

 resistance to phage in general. 



Perhaps a systematic study of the resistance of various bacteria, simultaneously 

 to various chemicals and phages, will open the way to a satisfactory explanation of 

 this question. 4 



SIGNIFICANCE OF BACTERIOPHAGE IN INFECTIOUS DISEASES 



Numerous investigators have shown that the distribution of bacteriophage in 

 nature is as wide as that of bacteria. It is universally agreed that when bacteriophage 

 is removed from its environment and placed under suitable conditions in contact 

 with susceptible bacteria in vitro, it causes their rapid disappearance. The question 

 naturally arises as to its effect on bacteria in the very environment where both exist 

 simultaneously, as in the intestinal canal of animals, or in polluted water or soil. It 

 is evident that if bacteriophage behaves in the human body, for instance, as it does 

 in a test tube, it must greatly influence the course of infection. This is actually 

 claimed by a number of investigators.^ 



The intestinal canal of a fetus does not contain any bacteriophage.'' In the first 

 few days of extra-uterine life, however, the intestinal canal becomes infected with 

 bacteria, and some time about the fourth to seventh day after birth phage can be 

 demonstrated in the feces. Usually the phage which shows its appearance at this 

 time is active against B. coli only.^ It has been claimed that, as result of infection 



' Grumbach, A., and Dimtza, A.: loc. cit. 



- Kimura, S.: Zlschr.f. Immnnitalsforsch. ii. exper. Thcnip., 42, 507. 1925. 



3 Sonnenschein, C: Centralbl. f. Bakteriol., Orig., 100, 11. 1926. 



■t Hoder, F., and Suzuki, K.: loc. cit. 



s d'Herelle calls attention to the fact that phage therapy in its crudest form was practiced in 

 connection with dysentery in the Middle Ages (d'Herelle F.: Proc. Amsterdam Acad. Sc, p. 836. 

 1925)- 



* d'Herelle, V.: The Bacteriophage and Its Behavior, p. 423. 1926; Pierret, R., and Bilouct, 

 v.: Compt. rend. Soc. de bioL, 93, 635. 1925; Sanderson, E. S.: /. Exper. Med., 42, 377. 1925. 



'Suranyi, L., and Kramar, E.: Monalschr.f. Kinderh., 28, 330. 1924. 



