400 THE BACTERIOPHAGE AND ITS BEHAVIOR 



many years ago thoroughly studied and explained this question of 

 anti-antisera. 



9. THE ACTION OF ANTIBACTERIAL SERA 



Various authors (Bail/^ Machado and da Costa Cruz/^'-'^^^ and others) 

 have attempted to show that a serum which is purely antibacterial 

 can neutraUze the action of the bacteriophage to the same degree and 

 in the same way as does an antibacteriophagic serum. 



Machado and da Costa Cruz^^^-^" provide experimental data ac- 

 cording to which it would appear that the addition of a single drop of 

 an anti-Shiga serum, with an agglutinating titre of 1:5000, to 10 cc. 

 of bouillon inoculated with 16 drops of a suspension of the bacteriophage 

 impairs bacteriophagic action to some extent. If 10 drops of the anti- 

 bacterial serum is added to 16 drops of the bacteriophage suspension 

 the action of the bacteriophage is completely prevented. 



They further found that if an extract of Shiga bacilli was added to 

 the bouillon the inhibitory action of the antibacterial serum was 

 abolished; bacteriophagy took place. 



They concluded, as had Bail in an earUer contribution, that the 

 neutraHzing action of an antibacterial serum and of an antibacterio- 

 phagic serum upon the bacteriophage is of the same nature. 



But proof to the contrary can be obtained in a very simple manner. 

 If a drop of a suspension of the bacteriophage is added to 10 cc. of the 

 homologous antibacterial serum, that is, a serum agglutinating the 

 bacterium at the expense of which the bacteriophage had developed, it 

 will be found after any interval of time whatever, in my experiments 

 varying from 1 day to 6 months, that the proportion of living and virulent 

 corpuscles is exactly the same as in a control preparation made with 

 physiological saline. 



These experiments have been made with a Shiga-bacteriophage and 

 an anti-Shiga serum, agglutinating at 1 : 6500, derived from a horse; with 

 a Coli-bacteriophage and the serum of a rabbit which had received a 

 series of injections with the same strain of B. coli as that used in making 

 the passages of the bacteriophage; and with a Staphylo-bacteriophage 

 and its corresponding antistaphylococcus serum. The results with 

 these various antisera and with the diverse races of the bacteriophage 

 warrant the conclusion that an antibacterial serum does not exercise 

 the slightest destructive effect upon the bacteriophage itself. 



In their determinations Machado and da Costa Cruz must have 

 worked with a Shiga-bacteriophage of low virulence, for in repeating 



