ANAPHYLAXIS 25 



others carry on until a mixed vaccine is discovered to be 

 necessary. Success in vaccine-therapy also depends on 

 the correct dosage and the observance of a right interval 

 between doses. 



Anaphylaxis. Instead of an injection rendering the 

 subject less sensitive to further injections of the same 

 substance, the reverse sometimes occurs, certain poisons 

 creating a peculiar sensibility on the part of the organism 

 towards themselves under conditions that would lead one 

 to anticipate a tolerance. Delille defines anaphylaxis as 

 ' a state of acquired vulnerability in an organism to a 

 second injection of a substance to which, at the time of 

 its first injection, it was indifferent.' For the production 

 of anaphylaxis an interval (the latent or incubation period) 

 must elapse between the first or sensitising dose and the 

 second or reacting dose. The minimum length of time 

 is said to be ten days, and should the second dose be 

 administered within this time anaphylaxis will not develop. 

 The length of time for which a sensitising dose will remain 

 effective in increasing sensibility is not known. 



Anaphylaxis is in some measure specific i.e., the 

 second injection must be of the same nature as the first. 

 While it has been mainly studied by the injection of horse 

 serum into guinea-pigs, the phenomenon has been obtained 

 with proteins, toxins, animal sera, glycogen, peptone, 

 trypsin, saponin, sodium oleate, in fact it is asserted that 

 any colloid will induce anaphylaxis. While crystals do 

 not produce the reaction, quinine, antipyrin, and iodoform 

 are apparent exceptions, and in some predisposed persons 

 inevitably lead to urticaria and anaphylactic sickness. 



It is necessary that the substance injected be foreign to 

 the animal used, and that the sani3 or an allied substance 

 be employed for the reacting as for the sensitising in- 

 jection. A guinea-pig sensitised with horse serum will 

 not react if the second injection be sheep serum or goat 

 serum, but it should react if the second injection be donkey 

 or mule serum. 



Animals injected with a particular organism are 

 anaphylactised by the corresponding toxin in a strictly 

 specific manner. Curious to say, it is necessary that the 

 sensitising and the exciting dose must take place through 

 the same route. 



Anaphylaxis in vitro may be induced by adding horse 



