268 THE BACTERIOPHAGE AND ITS BEHAVIOR 



B. dysenteriae. There are, then, two "diseases" affecting staphylococci, 

 the one probably "organic" and caused by a change of an enzymatic 

 nature,^ — the phenomenon of bacterioclysis of Twort. The other is 

 certainly of an infectious nature, as is proved by the data to appear in a 

 later chapter,— this is the phenomenon of bacteriophagy. 



Do both of these phenomena take place with B. pyocyaneus? It is 

 very probable. But however that may be, insofar as the phenomenon 

 of bacterioclysis of B. pyocyaneus is concerned, we have absolute 

 proof that it is not due to a bacteriophage. We will see, as a matter of 

 fact, in a later chapter, that all bacteriophages, whatever may be the 

 race to which they belong and whatever may be the bacterium at the 

 expense of which they reproduce, pass through collodion ultra-filters 

 if the pores are sufficiently open to permit the passage of the serum 

 albumin micella.* But the agent which causes the phenomenon of 

 irridescent spots on B. pyocyaneus cultures does not pass through collo- 

 dion filters, as shown first by Otto and Munter.^^^ These authors have 

 not, however, drawn any deductions from this fact. I have investigated 

 the question and I have shown that the diameter of the particles which 

 are responsible for this phenomenon is far greater than that of the 

 bacteriophage corpuscles. Taking as test material a mixture of races 

 of the bacteriophage active for B. dysenteriae, B. coli, B. typhosus, B. 

 pestis, and the staphylococcus, all of the races pass through or all do not 

 pass through, depending on the size of the pores. I have then added 

 to this mixture of bacteriophage races the "principle" responsible for 

 the phenomenon of bacterioclysis with B. pyocyaneus and I have never 

 found this to pass through. Seven strains of B. pyocyaneus, all giving 

 these irridescent spots, have given uniformly negative results. 



Therefore, the phenomenon observed with B. pyocyaneus can not be 

 bacteriophagy. Its manifestations are entirely different and it is 

 caused by a principle which lacks the characteristics of the bacterio- 

 phage. The principle is certainly associated in some way with the func- 

 tion of pigment production, for all strains which produce pyocyanin 

 show these iridescent spots upon agar, their number, and their extent 

 as well, being related to the quantity of pigment produced. 



* Some authors do not appear to realize that the size of the pores depends upon 

 the mode of preparation. They speak of membranes without specifying the size 

 of the pores. To say, as certain authors have said, that "the bacteriophage does 

 not pass through collodion membranes" is exactly the same thing as sajdng "mice 

 can not pass through holes." In one case, just as in the other, it is necessary to 

 specify the size of the hole which restricts the passage. 



