120 ESSENTIALS OF BACTERIOLOGY 



Products of Tubercle Bacilli. The true nature of the 

 tubercle toxin is not yet clear. It is not unlikely that several 

 toxic bodies differing from one another in their properties are 

 produced. Koch's tuberculin (1890), a bacterioprotein, was 

 obtained by filtering through unglazed porcelain, concen- 

 trated glycerin bouillon cultures of tubercle bacilli. It was 

 speedily shown to be devoid of curative power, and is now 

 used mainly for diagnosing the disease in cattle. In healthy 

 animals little or no reaction is produced by the injection of 30 

 to 40 eg. of tuberculin, but if tuberculous, the temperature 

 rises 2 to 3 F . in eight to tw r elve hours, and remains elevated 

 for a like period of time and may in larger doses prove fatal. 

 It is dangerous unless used carefully. 



Tuberculocidin. This is an albuminoid obtained from the 

 original tuberculin by precipitation with alcohol. Klebs 

 used it as a treatment for tuberculosis. 



Tuberculin residuum, an emulsion from the residuum, 

 hence the name, T. R., is an extract made from dried and 

 powdered living bacilli, and was recommended by Koch in 

 place of the original or old tuberculin, O. T. 



Koch's bacillen emulsion (B. E.) is similar to tuberculin R, 

 and is a glycerin emulsion of crushed bacteria, this being the 

 entire substance instead of an extract. Theo. Smith recom- 

 mends virulent uncrushed bacteria killed by moderate heat. 



Denys' B. F. (bouillon nitrate) tuberculin is a filtrate of 

 liquid cultures to which 0.25 per cent, phenol has been 

 added and allowed to stand two weeks. It is prepared in 

 eight dilutions. 



Opsonic Treatment. In recent years the use of tuberculin 

 R has again been brought forward by Wright and others and 

 curative claims made for it. It is used in very small doses 

 TT$Vo milligram at intervals of several days, and the effect on 

 "he opsonic index carefully watched. 



Use of Tuberculin. In the use of tuberculin severe reactions 

 are to be avoided. The smallest dose possible is commenced 

 with. Trudeau uses for afebrile cases a solution containing 

 milligram, liquid measure, Koch's B. E., or Denys' B. F., 



