UBIQUITY OF BACTERIOPHAGE 435 



fact that animals are unquestionably ingesting all of the time a wide 

 variety of races. The most logical explanation for this apparently 

 illogical situation is that most probably only that race which forms a 

 symbiosis with the intestinal B. coli persists. 



8. THE BACTERIOPHAGE IN THE EXTERNAL ENVIRONMENT 



From the data which have been presented in previous chapters 

 it is obvious that the bacteriophage protobe possesses a high degree 

 of vitality. Its resistance to the different destructive agencies to which 

 it is exposed in nature, — a resistance almost equal to that of the bac- 

 terial spores,- — permits it to survive the majority of influences to which 

 natural conditions subject it. Because of its minute size it is certainly 

 carried by seepage water through soils which are impermeable to bac- 

 teria. It should, because of these facts be found in all materials which, 

 at any time, have been exposed to pollution by excreta. And this is, 

 in fact, what the studies of many investigators show to be the case. 



Without discussing the presence of the bacteriophage in food prod- 

 ucts, and it has been found there (sausage ; van der Hoeden^"*) because 

 of some accidental contamination occurring in the abattoir or in the 

 manipulation of the product; without considering its presence, a per- 

 fectly natural thing, in products derived from the intestinal mucosa, 

 such as enterokinase (Pico,^i° Kuttner,^^^ Borchardt^^),* it is of signifi- 

 cance to know that the bacteriophage may be found in the external 

 world, particularly in drinking water. 



* The presence of the bacteriophage being constant in the intestine as is readily 

 demonstrated, particularly in animals because of the multiple virulences which 

 it shows, it is perfectly natural to find it in products derived from the intestine. 

 The three authors mentioned have, however, constructed theories as to the nature 

 of the bacteriophage on the basis of their findings. According to their method 

 of reasoning, inasmuch as the bacteriophage may be found in products derived 

 from the intestine it must be an intestinal enzyme. As it is easy to demonstrate 

 that B. coli is present in commercial preparations of enterokinase, and even of 

 pancreatin, one might just as logically conclude that B. coli is derived from the 

 intestinal enzymes. As a matter of fact, Combiesco"^ has shown that when the 

 bacteriophage is present in preparations of trypsin and of enterokinase, it repre- 

 sents an impurity, for it resists a temperature which destroys the enzyme. Fol- 

 lowing out the same idea, I have purified contaminated samples of enterokinase 

 by treating them with anhydrous glycerol or with alcohol. The bacteriophage is 

 destroyed by either the glycerol or alcohol, while the enzymes are left unmodified, 

 at least for a period of time adequate for the destruction of the bacteriophage. 

 Flu^'s has shown that the pancreatic juice of the cat, if collected without admix- 

 ture with other substances, never contains a bacteriophage. 



