296 ' TUBERCULOSIS 



five weeks, to inoculate tubes of solidified blood serum, under 

 strict aseptic precautions, with portions of a tubercular organ, 

 e.g. the spleen. The portions of tissue should be fairly large, 

 and should be well rubbed into the broken surface of the medium. 

 Cultures may, however, be obtained from sputum by means of 

 antiformin, as this substance readily kills most of the ordinary 

 bacteria and has comparatively slight effect on the tubercle 

 bacillus. Antiforrain should be allowed to act on sputum in 

 the proportion and for the time mentioned in paragraph (1), the 

 mixture should then be centrifugalised, the supernatant fluid 

 removed, and the deposit washed with sterile water and again 

 centrifugalised, these processes being repeated several times. If, 

 then, inoculations be made from the deposit on blood serum or 

 on Dorset's egg medium, pure cultures of the tubercle bacillus 

 may, in some instances, be obtained. The method is one which 

 gives good results. Another somewhat similar method is that 

 introduced by Twort ; in this, portions of sputum are exposed 

 to the action of a 2 per cent, solution of ericolin (a glucoside) for 

 an hour at 38 C., and thereafter cultures are made on Dorset's 

 medium. 



(4) Reactive phenomena. The presence of immune-substances 

 in the blood and the tuberculin reaction, along with the methods 

 of applying the respective tests, have been described above 

 (p. 284). 



