DETECTION OF THE BACILLUS 343 



agar. Bezancon and Griffon obtained cultures in 12-15 days from ten cases 

 of tuberculous meningitis by sowing the cerebro-spinal fluid. And the 

 same authors obtained cultures of the tubercle bacillus in two cases of sero- 

 fibrinous pleurisy. 



The classical method is to inoculate a guinea-pig with the suspected fluid. 

 But in this connexion it must be borne in mind that inoculation of tuberculous 

 pleural fluid gives negative results in three-quarters of the cases. [This 

 is probably because the fluid is actually free from tubercle bacilli since "an 

 extremely small number of bacilli is able to induce a progressive tuberculosis 

 in the guinea-pig " (A. S. Griffith, for the English Commission).] Inoculation 

 is best done into the peritoneum with a large quantity (10-15 c.c.) of the fluid, 

 which must, of course, be collected aseptically. To ascertain the degree of 

 virulence of the bacillus a rabbit should be inoculated at the same time, for 

 a, bacillus which will infect a guinea-pig often produces no lesion in a rabbit 

 (Arloing). [Rabbits inoculated with very small doses of the human tubercle 

 bacillus frequently show no tuberculous lesions when killed (English Com 

 mission).] 



Debove and Renault's method. Debove and Renault have devised a very ingenious 

 method for deciding the nature of a suspected tuberculous exudate. They showed 

 that tuberculous exudates contain tuberculin. The inoculation of a small quantity 

 of a pleural or pericardial exudate into a tuberculous guinea-pig gives the charac- 

 teristic tuberculin reaction (p. 324). 



E. Granulomata. 



In the majority of cases microscopical examination fails to reveal the 

 presence of the tubercle bacillus. A small piece of the growth should in this 

 event be inoculated beneath the skin of a guinea-pig. 



F. Nasal cavities. 



Strauss has shown that tubercle bacilli are frequently found (once out of 

 three times) in the nasal fossse of healthy subjects living in close contact 

 with persons suffering from phthisis. The following paragraph describes 

 Strauss' technique. 



Prepare a number of small swabs by rolling a little piece of absorbent wool round 

 the end of a small stick of wood (10-15 cm. long) [or stout iron wire] and sterilize 

 them in wool-plugged test tubes in the hot air sterilizer. Pass one of these sterile 

 swabs into the nasal cavity and by rubbing it gently over the mucous membrane 

 collect the dust and mucus adhering to it. Wash the swab in a little sterile water. 

 Repeat the operation six or eight times in each case and wash the different swabs 

 in the same water, then inoculate the emulsion into the peritoneal cavity of a guinea- 

 pig- 



G. Urine. 



Microscopical examination for tubercle bacilli of the urine of patients 

 affected with tuberculosis of the urinary passages often gives negative results 

 even when the urine has been centrifuged and the deposit used for examination. 

 It must not be expected that large numbers of bacilli will be found even in 

 the most favourable cases : should, however, a large number of acid-fast 

 bacilli be found on microscopical examination of a urine the result should be 

 regarded with suspicion and the examination done again, decolourizing with 

 alcohol for a long time. This would be a typical case for inoculation. 



In cases of acute tuberculosis even when there is no lesion of the urinary 

 passages the tubercle bacillus may pass into the urine (Benda, Weichselbaum, 

 L. Fournier and Beaufume). 



