710 



Tuberculosis 



lung for the purpose. The tissues are first cooked in a steam ster- 

 ilizer, then cut into prisms, placed in a Roux tube, an addition of 6 

 to 8 per cent, glycerin-water added, so as to bathe the lower part 

 "of the tissue and keep it moist, and the 

 whole then sterilized in the autoclave. 



The organisms are planted upon the tis- 

 sue, the top of the tube closed with a 

 rubber cap, and the culture placed in the 

 thermostat. The tubercle bacilli -grow 

 quickly and luxuriantly. 



Bouillon. — Upon bouillon to which 6 per 

 cent, of glycerin has been added the 

 bacillus grows well, provided the trans- 

 planted material be in a condition to float. 

 The organism being purely aerobic grows 

 only at the surface, where a much 

 wrinkled, creamy white, brittle pellicle 

 forms. 



Non-albuminous Media.- — Instead of re- 

 quiring the most concentrated albuminous 

 media, as was once supposed, Proskauer 

 and Beck* have shown that the organism 

 can be made to grow in non-albuminous 

 media containing asparagin, and that it 

 can even be induced to grow upon a mix- 

 ture oi commercial ammonium carbonate, 

 0.35 per cent.; primary potassium phos- 

 phate, 0.15 per cent.; magnesium sulphate, 

 0.25 per cent.; glycerin, 1.5 per cent. 

 Tuberculin was produced in this mixture. 

 Gelatin. — The tubercle bacillus can be 

 grown in gelatin to which glycerin has 

 been added, but as its development takes 

 place only at 37° to 38°C., a temperature 

 at which gelatin is always liquid, its use 

 for the purpose has no advantages. 



Appearance of the Cultures. — Irre- 

 spective of the media upbn which they 

 are grown, cultures of the tubercle bacillus 

 present certain characteristics which serve 

 to separate them from the majority of 

 other organisms, though insufi&cient to 

 enable one to identify them with certainty. 

 The bacterial masses make their ap- 

 As a rule very little growth can be ob- 

 served at the end of a week, and sometimes a month must elapse 

 before the growth is distinct. 



* "Zeitschrift tiir Hygiene," Aug. 10, 1894, xvm, No. i. 



Fig. 281. — Bacillus tuber- 

 culosis; glycerin agar-agar 

 culture, several months old 

 (Curtis). 



pearance very slowly. 



