384 THE BACTERIOPHAGE AND ITS BEHAVIOR 



last injection. Their first observation showed that the serum of the 

 rabbit so treated had no effect upon the growth of B. coli. They then 

 mixed a suspension of the homologous CoU-bacteriophage and the 

 serum, and introducing 5 drops of this mixture into bouillon which 

 they then seeded with a drop of a B. coli culture, they found that 

 after incubation the colon bacilli had developed as abundantly as in a 

 control tube which did not'^contain bacteriophage. From this they 

 concluded that the serum of the animal, prepared by injections of the 

 bacteriophage, possessed antibacteriophagic properties; that in the 

 presence of the antiserum the bacteriophage failed to manifest its 

 presence by the usual reaction. 



They heated, according to their method, the culture which had re- 

 ceived the mixture of antiserum and of bacteriophage at 58°C., ef- 

 fected a few passages, and found that the bacteriophage was absent. 

 Consequently, there has been, they said, a destruction through the 

 action of the serum. We will ascertain in a moment if this last de- 

 duction is correct. 



However that may be, whether the observed effect was due to an 

 inhibition or a destruction, the fact remains that the serum of an ani- 

 mal, prepared by injections of a bacteriophage suspension, possesses 

 an antibacteriophagic property. 



The first serum obtained by Bordet and Ciuca neutrahzed the action 

 of ten times its volume of a suspension of the homologous bacterio- 

 phage. They then found that the antiserum inhibited the process 

 of bacteriophagy both on agar and in a liquid medium, for when they 

 impregnated agar slants with the serum, and implanted them with a 

 secondary culture of bacteriophage-5. coli, they obtained a normal 

 growth, from which the subcultures remained normal indefinitely. 

 The B. coli was "cured," as they expressed it. But if these bacteria 

 have been cured, they remain resistant nevertheless. Bruynoghe^^^ 

 seeded a mixed culture of bacteriophage-^, coli into a mixture of 

 equal parts of bouillon and antiserum. After a series of 6 subcultures 

 he isolated colonies on agar and found that all of them were resistant. 



Bordet and Ciuca also noted that the antibacteriophagic property 

 of a serum could be estabhshed passively. When a normal rabbit is 

 injected with some blood from a rabbit which has received repeated 

 injections of the bacteriophage, within a few hours the blood of the 

 normal rabbit has acquired the antibacteriophagic property. 



And finally, they observed that after a series of injections of cultures 

 of normal B. coli,- — the same strain as that at whose expense the bac- 



