TUBERCULIN DIAGNOSIS. 



CHART i . Example of a diag- 

 nostic tuberculin reaction. 



0.3 C. then the dosage at the second injection 

 should not be increased to 5 mg., but the same 

 amount i mg. T. is to be repeated. In a tuber- 

 culous individual this repeated injection of i 

 mg. frequently results in a distinctly positive 

 reaction, while in a non-tuberculous patient in- 

 stead of the former doubtful, a distinct negative 

 reaction is obtained. 



The general rules given for the first inocula- 

 tion also apply to the second with 5 mg. In a 

 doubtful reaction with this dose, one does not 

 directly proceed to the 10 mg. dosage, but the 5 

 mg. dose is repeated and only after a negative 

 reaction with the repeated 5 mg. dose are the 

 10 mg. injected (see accompanying Chart i). 

 This represents the maximum amount of tuber- 

 culin to be used for diagnostic purposes. Koch 

 advises repetit on of this dose if no reaction is 

 obtained. The majority of authorities, however, 

 abstain therefrom. In fact some investigators 

 claim that a reaction obtained after inoculat on 

 of 10 mg. cannot be considered specific, because 

 there is a class of non- tubercular individuals 

 that responds to this quantity of tuberculin. 



Most tuberculous persons react after a dose 

 of i to 5 mg. T.; those, however, who are very far 

 advanced or who suffer from severe cachexia, 

 remain unresponsive to even much greater doses ; 

 in addition, patients whose serum contains anti- 

 tuberculin, do not react because the inoculated 

 tuberculin is quickly neutralized. 



According to Loewenstein the tuberculin 



Loewenstein's reaction does not depend so much upon 



Dosage the quantity of the tuberculin, as upon 



Scheme. the frequency that it is injected. He, 



therefore, advises that the same amount, 

 about 0.2 mg. be inoculated four times during the 

 course of twelve to sixteen days. And the results are 

 that in by far the greater majority of tuberculous patients 

 a typical reaction appears after the third or fourth in- 

 jection. The author has no personal experience with 

 this method, but the reports of other authorities do not 

 exhibit as favorable results as those claimed by Loewen- 

 stein. 



