312 IMMUNOLOGICAL METHODS OF DIAGNOSIS 



observed the development of increased redness and swelling, more- 

 over, give evidence of a direct effect upon the seat of infection. 

 The same is shown by the increase in the number of the rales and 

 in the number of bacilli in the sputum, if the injection is given in 

 a case of pulmonary tuberculosis (focal reactions). 



If, on the other hand, the tuberculin is administered in such a 

 manner that active resorption does not occur, local reactions only 

 will be observed, and in tissues, it should be remembered, which 

 are not tubercular in themselves. Following a cutaneous inoculation 

 with tuberculin an inflammatory papule thus appears, no matter 

 at what point the injection is made (v. Pirquet reaction), instillation 

 into the conjunctival sac gives rise to an intense conjunctivitis 

 (Calmette reaction) ; innunction with a tubercular salve calls forth a 

 local dermatitis (Moro reaction), etc. 



Owing to this remarkable hypersusceptibility to tuberculin on 

 the part of the tubercular subject, the principle in question has been 

 extensively utilized for diagnostic purposes, and it may not be out 

 of place to briefly describe the most important methods which have 

 been advocated for this purpose. 



The Tuberculin Test According to Koch (Subcutaneous Method). 

 The material which is employed to this end is the old tuberculin of 

 Koch. Of this the patient receives from 0.1 to 1 milligram, accord- 

 ing to the condition of his general health. In feeble individuals 

 it is best to start with 0.1 milligram, while more robust persons 

 may take 1 milligram. The injections are conveniently given in 

 the back, below the angle of the scapula, and best during the early 

 forenoon hours. To w T ait until the evening is not advisable, as the 

 reaction may occur already after six hours and might accordingly 

 be overlooked during the night. If no elevation of temperature 

 occurs after the first dose the quantity is doubled in forty-eight hours, 

 and so on until a dose of 10 milligrams, or in individuals of feeble 

 constitution, of 5 milligrams is reached. This Koch regards as the 

 limit, beyond which a reaction cannot be considered as specific. 

 Should elevation of temperature follow any one of the injections, 

 even though amounting to but three-tenths of a degree (C.), the 

 next dose should be of the same size, but it is not to be given until 

 the temperature has returned to normal. It will often be found, 

 then, that the second reaction is more marked than the first. Such 

 an occurrence Koch regards as particularly characteristic, and, 

 indeed, as an infallible indication of the existence of tuberculosis. 



