84 THE BACTERIOPHAGE AND ITS BEHAVIOR 



The following protocol deals also with B. dysenteriae, but with another 

 race of the bacteriophage. It has already been published^^^ in reply to 

 the communications of several authors, Bordet among others, who have 

 affirmed that the bacteriophage principle exists in a soluble form, 

 despite the proof of corpuscular nature which I had given from the time 

 of my first publication''^'' and which has been re-stated at different times. 

 Incidentally, none of these authors have discussed this experiment; 

 they have all passed it over in silence. In an effort to make the matter 

 clear, and to settle the point at issue I have presented the data several 

 times, and have even offered, in case any doubt remained, to actually 

 demonstrate the phenomenon. No one accepted the challenge, indeed, 

 no one has since even mentioned the question. 



In this experiment, 10 cc. of a 10~^*' dilution of a bacteriophage prin- 

 ciple active for B. dysenteriae were distributed, 1 cc. to each tube, into 

 10 supensions of dysentery bacilli. In 5 of these suspensions bacterio- 

 phagy was complete; in the other 5 the phenomenon did not take place; 

 they remained cloudy. 



Additional experiments of the same nature, carried out with a princi- 

 ple extremely active for the Staphylococcus aureus follow. 



Ten cubic centimeters of a 10"^" dilution of this bacteriophage prin- 

 ciple were divided, 1 cc. to each tube, among 10 tubes each containing 

 a suspension of 100 million staphylococci per cc. After 72 hours of 

 incubation at 32°C. all 10 suspensions were clear. Ten cc. of the 10~^^ 

 dilution of the same principle were Ukewise distributed among 10 tubes 

 of the same staphylococcus suspension. After 72 hours at 32°, 2 were 

 clear, 8 were turbid. 



In the same way, 10 cc. of the 10~^- dilution were distributed among 10 

 tubes of the suspension. After 72 hours all were turbid. 



Each of the two dissolved suspensions, obtained by adding the 

 material of the 10^^^ dilution, was in turn diluted to 10~^'. The 10 cc. 

 of each of these two dilutions were distributed into 10 tubes of staphylo- 

 coccus suspension. After 72 hours incubation at 32°C., of the 10 

 suspensions to each of which was added 1 cc. of one of the dilutions, 1 

 was clear, 9 were turbid; for the second dilution, 2 were clear, 8 were 

 cloudy. 



All of the suspensions which remained turbid were subjected to 

 numerous control examinations and all yielded normal cultures of the 

 staphylococcus. These turbid suspensions have been filtered serially, 

 and in no case did the filtrates cause the shghtest reaction which could 

 be ascribed to bacteriophagy. 



