TUBERCULOSIS TUBERCULIN THERAPY 



717 



fragmented tubercle bacilli, with their contained endotoxins, Koch 

 added T. R. and later B. E. to his list, in order to make the production 

 of antibacterial substances still more complete. Furthermore, in order to 

 obtain as varied a supply of antibodies as possible the use of several 

 tuberculins, such as old tuberculin and bacillus emulsion, was recom- 

 mended for use in the same patient. 



2. New Tuberculin (Known as T. R. or Tuberculin Residue). This 

 was the next tuberculin to be promulgated by Koch, 1 and is prepared as 

 follows: Virulent cultures of human tubercle bacilli are grown in flasks 

 of nutrient glycerin broth for from four to six weeks, the bacilli being 

 then filtered off and dried in a vacuum. One gram of the dried tubercle 



FIG. 137. PREPARATION OF TUBERCULIN. 



A flask of bouillon culture of tubercle bacilli (three to four weeks), 

 layer of bacilli with stalactite formations. 



Note the surface 



bacilli is ground in an agate mortar until all the bacilli have been broken 

 up. To the pulverized mass 100 c.c. of distilled water are added, 

 and the mixture is then centrifugalized. The clear supernatant fluid 

 is poured off, and is now known as Tuberculin Oberes (T. O., not to be 

 confounded with O. T.). It contains substances not precipitable by 

 glycerin. The sediment is again dried, powdered, taken up in a small 

 amount of water, centrifuged, the supernatant fluid poured off, and the 

 process repeated until no sediment is precipitated except that composed 

 of gross accidental particles. The fluids resulting from all the centrif- 

 ugalizations, except the very first, are poured together and the total 

 should not measure more than 100 c.c. This opalescent fluid is preserved 

 with 20 per cent, of glycerin and is known as T. R. It should contain 

 1 Deutsch. med. Wochenschr., 1897, xxiii, 209. 



