THE TUBERCLE BACILLUS 493 



Other tuberculins are those of Beraneck/ highly recommended 

 cUnically by Sahli,^ that of Klebs,^ and the tubercuhn produced from 

 bovine tubercle bacilli by Spengler.* 



Diagnostic Use of Tuberculin. — Subcutaneous Use. — The preparation 

 usually employed for diagnostic purposes is Koch's "Old Tuberculin" 

 (Alttuberculin). This preparation is administered by hypodermic injec- 

 tion of small quantities obtained by means of dilutions. The dilutions 

 are best made with a 0.5 per cent aqueous carbohc acid solution. In 

 practice a 1 per cent solution is made by pipetting 0.1 c.c. of tuberculin 

 into 9.9 c.c. of the 0.5 per cent carbolic solution. A cubic centimeter 

 of this then contains 0.01 c.c. of tuberculin. One c.c. of this solution 

 added to 9 c.c. of 0.5 per cent carbolic acid gives a solution in whieh 

 each cubic centimeter contains 0.001 c.c, or 1 milligram of tuberculin. 

 The initial dosage in adults in Koch's ^ early work, and as used by 

 Beck * on a large number of patients, was 1 milligram. This, according 

 to present opinions, is too high, and most clinicians to-day prefer 0.1 

 to 0.2 of a milligram. If after three or four days no reaction has occurred, 

 a second dose of 1 milhgram is given. In the absence of reaction after 

 three further days, a third dose of 5 mgm. may be given and, under 

 similar conditions, a fourth of 10 mgm. This is the largest dose which 

 should ever be given, and absence of a reaction to this dose may gener- 

 ally be regarded as proof that the patient is free from tuberculosis. 

 Doses larger than 10 mgm. may give reactions in perfectly healthy 

 subjects. Increase in dosage should be carried out only when the 

 preceding dose has been entirely without reaction. In all cases it 

 should be remembered that absolute rules of dosage can not be made 

 and the condition and physique of each patient must be separately 

 judged. 



The reaction itself is recognized chiefly by the changes in tem- 

 perature. In a positive reaction the patient's temperature will begin 

 to increase within six to eight hours after injection, rising sharply within 

 a few hours to 0.5 or 1.5° higher than the temperature before injection. 

 It then sinks more gradually than it rose, the reaction usually being 

 complete within thirty to thirty-six hours. With the temperature there 



' Beraneck, Compt. rend, de I'acad. des sci., 1903. 

 2 Sahli, Corrbl. d. Schw. Aerzte, 1906. 

 ^Klebs, Cent. f. Bakt., 1896; Deut. med. Woch., 1907. 

 * Spengler, Deut. med. Woch., xxxi, 1904; xxxi and xxxiv, 1905. 

 ' Koch, Deut. med. Woch., 1890. 

 « Beck, Deut. med. Woch,, 1899. 

 32 



