340 THE BACTERIOPHAGE AND ITS BEHAVIOR 



Like the preceding, this experiment leaves no doubt as to the independ- 

 ence of the characters of the bacteriophage from the bacterium at whose 

 expense it has reproduced. The bacteriophage is, then, unquestionably 

 autonomous. 



IX. The autonomy of the bacteriophage is shown also by the experi- 

 ments of Bordet and Ciuca.^^ Indeed, these authors state that "Sero- 

 logical study indicates, therefore, that the lytic power is a really new 

 character." This is, in terms adapted to their point of view, a recogni- 

 tion of autonomy. 



We will see later, that as a result of the repeated injection of an ani- 

 mal with a bacteriophage suspension, an anti-bacteriophagic property 

 appears in its serum. 



Bordet and Ciuca treated some rabbits as follows: 



Rabbit 1; received a series of injections of a culture of normal B. 

 coli. 



Rabbit 2; received a like number of injections of this same B. coli 

 after it had been bacteriophaged. 



Rabbit 3; received the same series of injections of a secondary culture 

 derived from the same strain of B. coli. 



They found that the sera of the last two animals neutralized the 

 homologous bacteriophage, while the serum of the first had no neutra- 

 lizing property whatever. The bacteriophage possesses, then, antigenic 

 properties peculiar to itself and definitely different from those inherent in 

 the bacteria at whose expense it develops. Thus, it is an autonomous 

 being. 



Wollman and Brutsaert'^* have recently repeated this experiment and 

 have reached the same conclusion, — the autonomy of the bacteriophage. 



X. Proof of the autonomy is also derived from another experiment of 

 the same authors. Bordet and Ciuca^- impregnated agar slants with 

 the anti-bacteriophagic serum and then seeded them with a secondary 

 culture of bacteriophage-5, coli. After incubation they found that 

 the growth was a normal culture of B. coli, all sub-cultures were normal, 

 and the bacteriophage had been eliminated, — that is, "cured" accord- 

 ing to Bordet's expression. 



If a bacterium iafected by a bacteriophage can be "cured" by serum 

 therapy it is evident that the bacteriophage must be a parasite, foreign 

 to the bacterium.* 



* Prausnitz^^^ saturated an anti-bacteriophagic serum (Shiga) with the homol- 

 ogous bacteria, and found that the antibacterial properties were removed while 

 the anti-bacteriophagic properties persisted. He concluded from this that the 

 bacteriophage is different from the bacterium, that is, an autonomous being. 



