CHAPTER XIV 



SERUM DIAGNOSIS 



IN addition to their use in the prevention and cure 

 of disease, biologic methods are of great value in diag- 

 nosis in certain affections. Among the curative sera 

 which are also of value in diagnosis, tuberculin holds 



first place. 



THE TUBERCULIN TEST 



As has been noted in the consideration of tuberculin 

 as a remedy when it is injected into an individual free 

 from tuberculosis, there occurs no disturbance of the 

 vital processes, but when administered in any consid- 

 erable amount to one affected with tuberculosis certain 

 disturbances arise which are referred to as a reaction. 



Tuberculin Reaction. The symptoms characteristic 

 of a tuberculin reaction are rise of temperature to one 

 or two degrees above normal, gastric disturbance, 

 headache, malaise, and what is termed the local reac- 

 tion, consisting of redness, swelling, and pain at the site 

 of injection and at the site of the disease. One, two, or 

 all of the above symptoms may be present in varying 

 degrees, depending upon the size of the dose, the sus- 

 ceptibility of the individual, and the stage of the disease. 



It will be noted that in the use of tuberculin in treat- 



115 



