56 TUBERCULIN DIAGNOSIS 



In young children on the other hand, v. Pirquet's method should be 

 the one of choice. In addition to its being entirely harmless, and easily 

 applied, it possesses a high diagnostic value. 



As for Koch's subcutaneous reaction, it is specific, inasmuch as it is a rare 

 exception to get a negative reaction in an active tuberculous process. 

 This occurs only in cases either with very severe cachexia or those with 

 freely circulating antituberculin in* the blood. If the latter two possi- 

 bilities are excluded, the absence of a positive reaction speaks decidedly in 

 favor of the absence of tuberculosis. 



The interpretation of a positive reaction as to the existence of clinically 

 active tuberculosis cannot be so definitely answered. From the recent 

 work of most authorities, however, it seems to be taken for granted that a 

 positive reaction does mean an active tuberculosis; still, this statement 

 requires a great deal of consideration and limitation. 



In this connection the statistics of Franz are of interest. Out of 400 

 apparently healthy soldiers in one of the Austrian regiments who in 1901 

 their first year of service, received an inoculation of 0.003 c.cm. of tuber- 

 culin, a positive result was found in 61 per cent, of the cases. In the fol- 

 lowing year (1902) 100 of the soldiers were re-inoculated and all of those 

 who reacted positively the first time, did so a second time, in some instances 

 even though the second dosage was smaller. Moreover, fourteen others 

 who responded negatively the previous year showed positive results this 

 time, making a total of 76 per cent. Out of 323 men inoculated for the 

 first time in 1902, 68 per cent, reacted positively. It must be mentioned, 

 however, that the majority of the members of this regiment came from a 

 very tuberculous 1 district. The same author also examined a Hungarian 

 regiment in a tuberculous-free district, and under similar circumstances 

 found a positive reaction in 38 per cent, of cases. Although these figures 

 may be exceptionally high, they are without doubt conclusive as to the 

 fact that Koch's reaction cannot be considered specific for "active" 

 tuberculosis. Franz in addition gives important statistics concerning the 

 health of the inoculated soldiers whom he examined for years following the 

 inoculation. The appended charts taken from the most recent publica- 

 tion of Franz (Wien. Klin. Woch., 1909, No. 28) tabulate what has been 

 said above. 



