ALLERGIC REACTIONS 287 



material under examination contains albumins which are still capable 

 of undergoing solution, even though they be present only in traces. 

 Uhlenhuth and Beuiner thus mention that they obtained positive 

 results with blood which had undergone putrefaction and had been 

 left exposed to the air for two years, as well as with dried blood 

 stains which were more than fifty years old. 



ALLERGIC REACTIONS 



By the term allergic reaction in the clinical sense we understand 

 the specific symptomatic response on the part of the infected and 

 hence sensitized organism to be parenteral reintroduction of the cor- 

 responding antigen. Among the infectious diseases such reactions 

 have been notably studied in connection with tuberculosis, but are 

 evidently destined to play an important role in the diagnosis of 

 other diseases as well. In the present work we shall confine our 

 attenton to the tubercular test and the luetin reaction in their 

 relation to the diagnosis of tuberculosis and syphilis respectively. 



The Tuberculin Test. It will be recalled that the tubercular guinea- 

 pig responds quite differently to the introduction of living tubercle 

 bacilli than does the normal animal. For whereas in the latter a 

 local reaction occurs only after from ten to fourteen days, definite 

 changes can be detected in the former already within twenty-four 

 to forty-eight hours. But while in the primarily non-tubercular 

 animal the local lesion then remains active to the end, local recovery 

 occurs in the reinjected tubercular pig. If an emulsion of dead 

 organisms (tuberculin) be used instead, as much as 0.5 gram may 

 be injected, intraperitoneally even, in the case of the normal animal 

 without producing any deleterious results, while similar treatment 

 of the tubercular guinea-pig would lead to a fatal ending. If the 

 injection is made subcutaneously, and the dose is chosen sufficiently 

 small as not to kill, a severe local reaction will result, as in the first 

 instance, where living organisms were used, and incidentally it will be 

 observed that in the tubercular in contradistinction to the non-tuber- 

 cular animal, temporarily at least, certain general symptoms of illness 

 develop, of which a rise in temperature is the most striking and the 

 most constant. Evidently the primary inoculation, while increasing 

 the resistance of the animal to subsequent infection with the organism 



