386 INFECTION AND IMMUNITY. 



Somewhat more difficult is the question regard- 

 ing the primary toxicity of such substances as are 

 contained in eel serum, various phytalbumins and 

 bacteria. It has been shown by Doerr and Kau- 

 bitschek that by heating or by acidifying eel serum 

 it is possible to remove the primary toxicity with- 

 out taking away the property of producing anaphy- 

 laxis. In a similar way it has been shown by 

 Eosenau and Anderson., Vaughan, and others, that 

 bacterial proteins free from toxic action can pro- 

 duce anaphylaxis. It has also been shown that 

 whereas in primarily toxic serum the larger the 

 dose the greater the toxicity, in anaphylaxis sensi- 

 tization smaller doses sensitize more readily than 

 large ones. 



That hypersusceptibility to true toxins does oc- 

 cur, however, has been demonstrated in the case of 

 diphtheria toxin and tetanus toxin. The phe- 

 nomena here, however, are distinct from anaphy- 

 laxis in the fact that the incubation period is 

 absent, that the symptoms come on gradually after 

 the second dose, and lastly, that after a certain 

 length of time which corresponds to the incuba- 

 tion time of anaphylaxis, immunity or decrease in 

 susceptibility, occurs in contrast to anaphylaxis. 

 We must conclude, then, that toxicity and sensi- 

 tizing properties are distinct from each other. 



The anaphylactogen comes into consideration in 

 and Toxicity. t j ie p r j mar y or sensitizing dose and in the second- 

 ary or toxic dose. Many experiments have been 

 carried out to determine whether or not the sen- 

 sitizing and toxic action are dependent on the 

 same substance or similar qualities of the same 

 substance. It was found, for instance, that in the 



