THE MECHANISM OF BACTERIOPHAGY 103 



fore. Nevertheless, no bacteria had been introduced into the bouillon 

 and obviously none of the bacteria present in the sac had been able to 

 reach the external medium, since the bacteriophage corpuscles, them- 

 selves much smaller than the bacteria, did not pass through the sac. 

 This last fact is the more certain since the culture in the sac did not 

 undergo bacteriophagy. 



Sacs of least permeability. Here no change took place after incuba- 

 tion. The number of corpuscles in the bouillon did not increase nor 

 did the bacterial culture within the sac show any evidence of bacteri- 

 ophagy.* 



WoUman concluded that even though bacteria were not present 

 the bacteriophage commenced to develop because of the presence of 

 certain diffusible bacillary products. These substances passed through 

 the membranes impermeable to the bacteriophage corpuscles. He 

 compared this behavior of the bacteriophage corpuscle to that of 

 Dictyostelium mucoroides. With this, a Myxomycete, Pinoyf has shown, 

 by means of a technic comparable to that of WoUman, that develop- 

 ment starts because of the presence of diffiusible products of B. 

 fluorescens, although normally, the IMyxomycete develops only in the 

 presence of living bacteria. 



Asheshov has personally told me that he has repeated Wollman's 

 experiment with the same results. 



It is necessary, then, to conclude that the multiplication of bacterio- 

 phage corpuscles can take place, at least to a certain degree, in the 

 absence of the bacterial cell, and that for this development the cor- 

 puscles utilizes certain diffusible products present in the culture of 

 susceptible bacteria. 



In any case, it is certain that these diffusible products can be utiUzed 

 by the bacteriophage corpuscle only immediately after their derivation 

 from the bacterium, for on several occasions, employing a variety of 

 procedures, I have tried to cultivate the corpuscles in filtered bac- 

 terial cultures or in autolysates, always unsuccessfully. This fully 

 agrees with further observations made by Pinoy on the Myxomycete, 

 which, although developing to some extent in bacterial products dif- 

 fusing through a collodion membrane never multipUes in autolysates 

 or in culture filtrates. 



* This last statement is based upon a verbal communication; it does not appear 

 in the paper of WoUman. ^^- 



t Pinoy, E. — Role des bacteries dans le developpement de certaines Myxomy- 

 cetes. Ann. Inst. Pasteur, 1907, £1, 622; 686. 



