274 THE BACTERIOPHAGE AND ITS BEHAVIOR 



certainly granules derived from the bacteria, granules which are as yet 

 undissolved. 



As for the granules which are to be seen within the bacteria during the 

 process of bacteriophagy, many observations but add to my belief that 

 they are bacteriophage corpuscles, or masses of corpuscles, visible 

 because of the difference in refraction between the substance of the 

 corpuscles and that of the bacterium. 



Filtrahility 



Because of the following experiment, I believe^^^ the bacteriophage 

 corpuscle to be about the same size as the molecule, or perhaps it would 

 be better to say, the micella, of serum globulin. 



To 100 cc. of physiological saline 10 cc. of a Shiga-bacteriophage fil- 

 trate and 2 cc. of an anti-tetanus serum were added. A few cubic 

 centimeters of this mixture were placed in each of a number of sacs, 

 prepared of collodion in such a way that the sacs of the series possessed 

 an increasing scale of permeability. Each sac was dialyzed against 

 physiological saline, the level of the fluid within the sac being 3 to 4 cm. 

 higher than that of the external fluid in order to provide a shght pressure. 

 Tests made under these conditions showed that with all of the sacs 

 through which the antitoxin passed, the bacteriophage passed also, 

 and that the bacteriophage was retained wherever the antitoxin failed 

 to dialyze. 



Subsequent experiments of this same type have been performed with 

 races of the bacteriophage virulent for B. coli, B. typhosus, Pasteurella 

 pestis, Pasteurella hovis, and for the staphylococcus and in all instances 

 the results have been similar to those detailed above. It is interesting 

 to note, however, that on many occasions I found that the bacteriophage 

 passed through the walls of the sac which, in the series of increasing 

 permeability came immediately before the first one which allowed pas- 

 sage of the globulins. This would suggest that the bacteriophage cor- 

 puscle may be slightly smaller than the micella of serum globuHn.* 



* Let us note in passing, that to state, as certain authors have done, that the 

 bacteriophage "passes," or "does not pass" through collodion membranes, with- 

 out specifying the degree of porosity of the membrane with which they were 

 working, is without meaning. It is the same as saying that "a mouse can not 

 pass through a hole," which is true if we are considering the eye of a needle, but 

 is manifestly false if we have in mind a railroad tunnel. 



These authors seem to be ignorant of the fact that collodion membranes may 

 be prepared in which the pores are greater than 100mm in diameter, while other 

 membranes may have pores of but 1mm- It is unfortunate that the published re- 

 sults warrant such comments. 



