58 TUBERCULIN DIAGNOSIS 



It is evident from the above figures that by the use of the i per cent, tuber- 

 culin a grade of specificity is reached which can be considered quite high, as 

 the non-tuberculous react only in a very small percentage of cases, while exist- 

 ing tuberculosis is detected in 80 per cent, of the subjects. Clinical examina- 

 tions of the positive reacting patients show that the latter belong to the 

 group of active tuberculosis. Absolute reliance, however, in the determi- 

 nation as to whether the positive reaction given is due to an active or 

 latent tuberculosis, cannot even be placed on the ophthalmo reaction. 



According to several authors, it is claimed that typhoid fever, rheumatism, and 

 syphilis (in the stage of eruption) are very prone to give a positive ophthalmo reaction, 

 without the presence of a simultaneously existing tuberculosis. 



In conclusion, therefore, the author finds it difficult to make any 

 general statement as to the preference of one or the other test for diagnostic 

 purposes. 



In children the application of the Pirquet reaction, and in adults the 

 ophthalmo reaction, are given preference to Koch's subcutaneous reaction; 

 provided, no contraindications exist against the first, and that treat- 

 ment with tuberculin is not to be undertaken. In the latter instance, the 

 recurrent ophthalmo reaction when the tuberculin therapy is instituted, 

 authorizes the use of Koch's subcutaneous diagnostic method. 



Mallein, Trichophytin. 



Similar to old tuberculin, the Mallein (Helmann and Kelning) has been obtained 

 from cultures of Glanders bacilli and the Trichophytin (Plato) has been isolated 

 from the Trichophyton fungi. Mallein has already attained its practical application 

 for the diagnosis of glanders in veterinary medicine. Like tuberculin it is harmless 

 in normal organisms, but brings about temperature and a local reaction at the site of 

 the injection when inoculated into glanders stricken animals. Various general symp- 

 toms may also appear. Its employment in a manner analogous to the ophthalmo 

 reaction is also possible. 



The Prognostic Value of the Local Tuberculin Reactions. 



The fact that the tuberculin reaction in cachectic tuberculous indi- 

 viduals is usually negative has led different observers to regard the degree 

 of the local reaction in a given case as a guide to the prognosis. If, as is 

 considered, the strength of a reaction depends upon the dose of tuberculin, 

 the degree of susceptibility of the organism and its reactive power, the 

 following theoretical possibilities may be considered. 



(a) With mild clinical manifestations, a reaction obtained only after 

 large doses of tuberculin would speak for a favorable prognosis because 

 the hypersusceptibility of the individual toward tuberculin is still mild. 



