250 A MANUAL OF BACTERIOLOGY 



or ten days after inoculation gives rise to whitish 

 or yellowish drops or ' scales.' There is no lique- 

 faction of the medium if the culture is perfectly 

 pure. The bacillus also grows on the surface of 

 bouillon (containing glycerine), forming a delicate 

 thin film. Pawlowsky 1 has grown the tubercle 

 bacillus on sterilised potatoes ; but to succeed with 

 this medium a considerable quantity of moisture 

 must be kept in contact with the growing microbe. 

 Nocard and Koux 2 have shown that most luxuriant 

 growths of the tubercle bacillus are readily obtained 

 when the microbe is grown on agar-agar and blood 

 serum to which 6-8 per cent, of glycerine has been 

 added ; but after many successive cultivations on 

 these glycerine media, the virulence of the microbe 

 becomes distinctly diminished. 



B. tuberculosis forms cellulose in the organs and 

 blood of tuberculous persons ; 3 and it has been 

 recently stated that the microbe, when growing in 

 glycerine bouillon, produces an albumose. 4 The 

 tubercle bacillus has great tenacity of life, for the 

 author 6 has shown that it is capable of being dried 

 up for three or four months at a temperature of 

 32 C. without losing its vitality : and Cornil was 

 able to demonstrate that at the ordinary temperature 

 of the room the tubercle bacillus, kept in water from 

 the Seine, still retained its vitality after seventy 



1 Annales de I'Institut Pasteur, 1888-9. 



2 Annales de I'Institut Pasteur, 1887, p. 19. 



3 See the author's Researches on Micro-Organisms, p. 155. 



4 Crookshank and Herroun in British Medical Journal, 1891, 

 p. 401. 



5 Proc. Roy. Soc. Edinburgh, vol. xv. p. 42. 



