TUBERCUL OSIS. 



219 



Kitasato's method of washing the sputum has been 

 modified and simplified by Czaplewski and Hensel. 1 In 

 their studies of whooping-cough, instead of washing the 

 flakes in water in dishes, they shook them in peptone 

 water in test-tubes. The shaking in the test-tube being 

 so much more thorough than the washing in dishes, fewer 

 changes are necessary, three or four washings being 

 sufficient. 



In 1887, Nocard and Roux gave a great impetus to 

 investigations upon tuberculosis by their discovery that 

 the addition of 4-8 per cent 

 of glycerin to bouillon and 

 agar-agar made them suitable 

 for the development of the 

 bacillus, and that a much 

 more luxuriant development 

 could be obtained upon these 

 media than upon blood-se- 

 rum. The growth upon such 

 * ' glycerin agar-agar " (Fig. 

 62) very much resembles 

 that upon blood-serum. The 

 growth upon bouillon with 

 4 per cent, of glycerin is 

 also luxuriant. As tubercle 

 bacilli require considerable 

 oxygen for their proper devel- 

 opment, they grow only upon 

 the surface of the bouillon, 

 where a rather thick myco- 

 derma forms. The surface- 

 growth is rather brittle, and after a time gradually sub- 

 sides fragment by fragment. 



The tubercle bacillus can be grown in gelatin to which 

 glycerin has been added, but as its development takes 

 place only at 37-38 C., a temperature at which gelatin is 

 always liquid, its use for the purpose is disadvantageous. 



1 Centralbl. f. Bakt. u. Parasitenk., xxii., Nos. 22 and 23, p. 643. 



FIG. 62. Bacillus tuberculosis on 

 " glycerin agar-agar." 



