674 ACTIVE IMMUNIZATION 



Unless one belongs to the ultra-conservative class of tuberculin 

 therapeutists, it is not a slight focal reaction that is to be avoided, but 

 those reactions that are large enough to manifest themselves by changes 

 in the physical signs or by decided symptoms. On the contrary, it is the 

 production of such slight hyperemia about the focus of disease that 

 constitutes the most valuable result of tuberculin therapy. It is well to 

 start with a minute dose, and push the dosage rapidly until a slight focal 

 reaction at the site of injection or mild pyrexia is observed. When a 

 mild focal reaction is not produced, the patient is not receiving his due 

 amount. 



Dosage. Since each patient is a law unto himself, the initial dose 

 should be so small that no harm can result from its use. White and Van 

 Norman make the initial dose equal to the quantity of. tuberculin 

 which, when applied cutaneously, will elicit a minimal reaction after 

 seventy-two hours. 



As regards the size of the initial dose, patients can be divided into 

 three classes: (1) Children; (2) patients who exhibit a slight pyrexia 

 or are not in good condition; (3) patients in good condition. The 

 following table of doses is that given by Hamman and Wolman, the 

 smaller initial dose being for classes 1 and 2, the larger for class 3. 



TABLE 26. INITIAL AND MAXIMAL DOSES OF THE COMMONLY USED 



TUBERCULINS 



Old tuberculin (0. T.) is put up in ampules holding 1 c.c. and 5 c.c. 

 From these, higher dilutions are prepared by adding sterile normal salt 

 solution, using sterile glassware, starting with a 1 : 10 (A) of the original 

 strength, then making a 1 : 10 from this (B), a 1 : 10 from that (C), a 

 1 : 10 from that (D), and so on to the desired dilution. As 1 c.c. of the 

 original product represents 1000 milligrams of the pure tuberculin, 1 c.c. 

 of dilution A will contain 100 milligrams; B, 10 milligrams; C, 1 milli- 

 gram; D, 0.1 milligram; E, 0.01 milligram, and F, 0.001 milligram, 

 which is the higher of the initial doses just given. 



New tuberculin (T. R.) is so prepared that 1 c.c. represents 5 milli- 

 grams of the dry powder. Dilutions may be prepared in a manner 



