58 THE TUBERCULIN THERAPY. 



T. R. is readily assimilated by patients. If carefully administered it produces very 

 little infiltration and only slight temperature and general reaction. Its price is com- 

 paratively high (i c.c. costs 8.50 marks). 



The first preparation which contained both the soluble and insoluble 

 elements of the living bacilli was the 



/. New Tuberculin Bacilli emulsion (B. E.) which consists of T. R.+ 

 T. O. 



The living tubercle bacilli are first pulverized in a mortar and then suspended in 

 salt solution. No centrifugalization is necessary, but sedimentation is adhered to, and 

 besides, 50 per cent, glycerin is added for preservation purposes. Next to T. the new 

 tuberculin B. E. has been most carefully studied. 



Equally lacking in being an ideal antigen is the B. E. inasmuch as immunity at- 

 tained by its injections is not at all proof against subsequent infection. 



Closely resembling the B. E. is 

 g. the Tuberculin Beraneck. 



BeVaneck produced two tuberculin preparations of which one is in the main identical 

 with TOA, while the other is an extract of tubercle bacilli with i per cent of phosphoric 

 acid. Both of these tuberculins are mixed together and applied. Sahli reports good 

 results with this mixture. 



Although none of the described tuberculin preparations can 



Action of be considered a true antigen for the tubercle bacillus, they 



Tuberculin, have nevertheless an undoubtedly favorable effect upon 



tuberculous individuals. To a certain extent the benefits 



must be said to be derived by the mechanism of partial immunization. This 



in itself does not, however, explain the entire phenomenon of their successful 



action. 



On examination of the tuberculous organs of animals treated with 

 tuberculin, there will be found within the healthy tissue surrounding the 

 tuberculous foci, a fresh inflammatory reaction. This consists of a sero- 

 fibrinous exudate and a zone of leucocytes intruding to a certain extent upon 

 the tubercular lesion. Tuberculin acts only upon tuberculous tissue which 

 is still alive and not upon dead, cheesy or necrotic structures. 



If enough tuberculin is given so that death of a tuberculous guinea-pig occurs> 

 the changes found are striking. On dissection, about the point of inoculation Koch 

 reports a marked congestion of the blood vessels giving a red and often an almost dark 

 violet appearance. This discoloration extends for a greater or less distance from the 

 site hi question. The neighboring lymph glands are similarly reddened. Besides the 

 tuberculous changes present within the liver and spleen, these organs show on their 

 surface many blackish-red spots varying in size from that of a pin-point to a hemp seed, 

 and resembling very closely the ecchymosis found in some infectious diseases. On 

 microscopical examination are found no blood extravasations, but very widely distended 

 capillaries directly surrounding the tuberculous foci. The capillaries are so densely 

 plugged with red blood cells that it seems almost impossible for the circulation to have 

 continued in these places. In exceptional cases only, are the blood vessels ruptured and 

 the escaped blood found within the tuberculous foci. The lung presents similar changes, 



