44 TUBERCULIN DIAGNOSIS. 



A part of the glycerin has, however, been used up for the nutrition of the bacteria and 

 thus it is highly probable that after four to six weeks the bouillon contains less than 

 5 per cent, glycerin and the evaporated solution less than 50 per cent. The specific 

 substances contained within the tuberculin have not been definitely established. As 

 probable elements, however, may be recorded, products of secretion of the living bacteria, 

 of degeneration of the dead bacilli and finally the glycerin soluble substances extracted 

 from the bacterial bodies during the heating. All these substances no doubt, and many 

 others about which we lack information, are directly concerned in the activity of the 

 tuberculin. 



Among the many unsolved questions which here present themselves may, in addi- 

 tion be mentioned the one, to the effect: whether any substances exist in the filtrate 

 which are thermolabile, and therefore destroyed or modified by the heating? Accord- 

 ing to Bail's researches, the aggressin of the tubercle bacillus differs from all other 

 aggressins in that it is not thermolabile and can moreover withstand high grades of 

 temperature. In spite of this though, attempts to eliminate the heating during the 

 manufacturing of the tuberculin should merit consideration. 



If merely the term "Tuberculin," is used one always has in mind the 

 filtrate tuberculin, also known as Old Tuberculin. 



The above described experiment with the tuberculous guinea-pigs has 

 its analogy in the use of tuberculin in the case of man. Here, however, in 

 order to avoid dangerous symptoms far smaller doses of tuberculin are 

 selected. 



If therefore of two individuals one is tuberculous and the 



The Tuber- other not, and both are injected with the same amount of old 



culin Reaction tuberculin o.ooi c.c., the healthy individual remains perfectly 



in Man. normal while the tuberculous person shows a typical symptom 



complex which can be described under, 



1. General reaction. 



2. Focal reaction. 



3. Local reaction. 



The General Reaction consists of, fever, headache, malaise, nausea, 

 insomnia, cough irritation, palpitation, etc. The most constant symptom 

 is increased temperature; the other manifestations may only be very mild 

 or even entirely absent. 



The Focal Reaction exhibits evidences of a fresh inflammatory process in 

 the suspicious or old tuberculous foci. In cases of lupus, laryngeal, and iris 

 tuberculosis, this inflammatory reaction can be distinctly seen. In pulmon- 

 ary tuberculosis the previously vague physical signs may now become defi- 

 nite; rales may appear, dulness may be increased, and eventually pains in 

 the chest may arise. 



The Local Reaction is noticed at the point of inoculation. In spite of the 

 sterile needle and thorough disinfection, the skin around the site of the 

 injection becomes red, swollen and painful. That this is not due to dirt 

 infection is proven by its absence in non-tuberculous individuals. 



