BACTERIOPHAGE AS AN ANTIGEN 403 



that this change may not prevent the fixation of the corpuscle to the 

 bacterial cell. 



To consider the phenomenon from another point of view, we know 

 that in order for the fixation to take place it is essential that there be an 

 approach of the corpuscles to the bacteria, and KabeHk^^"* seems to 

 have shown that the primum movens for this coming together resides 

 in a phenomenon of chemotaxis on the part of the bacteriophage cor- 

 puscle. This chemotaxis is necessarily determined by some bac- 

 terial product to be found in the liquid, in the same way, for example, 

 as the chemotaxis of the fern antherozoid for the oosphere is deter- 

 mined by a secretion of malic acid by the latter. If the antibacterial 

 substance precipitates the substance which determines the chemotaxis, 

 the drawing together can not occur.* 



Such are the hypotheses which may be formulated in an effort to 

 explain the mechanism whereby an antibacterial serum modifies the 

 process of bacteriophagy. Which hypothesis is true? I do not know. 

 But in any case, one fact is certain, and that is that such a serum 

 exerts no direct action upon the bacteriophage protobe itself. 



10. THE PHENOMENON OF ANTIPHYLAXIS 



When we immunize an animal by giving it a series of injections, 

 using cultures of a toxic bacterium, such as B. dysenteriae Shiga,'\ we 

 know that the serum of this animal acquires an antitoxic property. 



A culture of Shiga bacilli, transformed through bacteriophagy to a 

 suspension of bacteriophage protobes, still contains the bacillary 

 toxins. To be convinced of this it is only necessary to inject rabbits, 

 some with a quantity of culture sufficient to cause a posterior paralysis 

 and death, and others with a suspension of the bacteriophage im- 

 mediatelij after bacteriophagy. A comparison of the effects will show 

 that the latter substance is as toxic as is a normal culture, indeed, it 

 may be more so. 



* To the observation that in order to fix itself to the bacterium the bacteriophage 

 corpuscle may require that some product secreted by the bacterium be found in 

 the liquid, Hauduroy draws the singular conclusion that the bacteriophage must 

 bea "complex," formed of a living corpuscle and a soluble bacterial product. Man 

 has an incessant need for oxygen, but it would be a poor definition of a man to say 

 that he is a complex formed of a body and oxygen. Nor is the antherozoid of a 

 fern formed of a complex with malic acid. 



t Endo- or exo-toxins; what do we mean? As has been said by Nicolle the 

 urine is an endo-urine or an exo-urine, depending upon whether it is in the bladder 

 or in a test-tube. There is about the same difference between an endo- and an 

 exo-toxin, 



