212 PUBLIC HEALTH BACTERIOLOGY 



ANAPHYLAXIS. 



I. GENERAL PRINCIPLES. 



As already defined, anaphylaxis is a supersensitiveness 

 induced in man and animals by the injection of certain 

 substances, mostly, so far as is known, of an albuminous 

 nature. The ideas on this subject have grown around 

 anomalous phenomena following on the injection of diph- 

 theria toxin and antitoxin. Thus v. Behring and others 

 noted that occasionally animals highly immune to the 

 toxin showed excessive susceptibility to small doses of 

 the toxin. Very soon after the introduction of the serum 

 treatment of diphtheria in 1894, certain symptoms were 

 observed to follow the injection of the serum, which, at 

 first ascribed to the antitoxin contained in it, were finally 

 found to be due to the horse serum which carried the 

 antitoxin. These symptoms were hence called " Serum 

 Sickness " or " Serum Disease " and were mostly a rash 

 of an erythematous nature, and fever. These come on in 

 most cases about the ninth day, but vary from the third 

 to the nineteenth. Fever is not always present, and the 

 rash is quite often urticarial, and occasionally scarlatini- 

 form or morbilliform, is local to the point of injection or 

 becomes general, is fugitive or persistent. Articular 

 pains may accompany the rash, and may be severe. The 

 frequency of these symptoms varies ; from 30 to 55 

 per cent of the cases treated with serum are stated to 

 show them in some degree or other. Some oedema is 

 also noted by Currie, as accompanying the rash. The 

 similarity of these symptoms to those of the specific 

 infective diseases is striking, and led to the name " serum 

 disease," which has therefore an incubation period (after 

 subcutaneous injection) averaging nine days, and a 

 duration of two days on the average. That these 

 symptoms were due to the horse serum, and not to the 

 antitoxin, has been proved by such symptoms foUowing 

 the injection of the normal serum of the horse. Another 

 group of symptoms which on rare occasions followed the 

 use of serum, was not at once recognized as due to it, but 

 by the accumulation of cases and certain special features 

 connected with them, the causal action of the serum was 



