ASIATIC CHOLERA. 



365 



in a tauk which contained the water supply of a neighbourhood 

 where cholera cases occurred; but comma-shaped organisms are 

 frequently present in sewage-contaminated water. Koch's comma- 

 baciUi ai-e aerobic, and their development is arrested by deprivation 

 of oxygen. They are destroyed by drying on a co^'er glass, but 

 retain then' vitality longer when dried on silk threads. Cultures 

 are sterilised by exposure for fifteen minutes to 55° C, and by 

 various antiseptic substances. 



Fig. 154. — Purk-cultiv-\tioks in Xitriext Gklatink. a, Koch's Cholkr.\. 

 Bacillus, twenty-four hours old. b, Finklkr's Bacillus, twenty-four 

 hours old. 



Methods of Staining the Comma-bacilli of Koch. 



In cover-glass prepaiations they may be well stained in the ordinary 

 way, with an aqueous solution of methyl-violet or fuchsine, or by the 

 rapid method, without passing through the flame (p. 85, Babes' method). 



yicati and Reifgch'.-i method. 



A small quantity of the stools, or of the scraping of the intestinal 

 mucous membrane, is spread out on a glass slide and dried, then steeped 

 during some seconds in sublimate solution, or in osmic acid (1 to 100). 

 It is then stained by immersion in fuchsine-aniUne solution (1 or 2 

 grammes of Bile fuchsine dissolved in a saturated aqueous solution of 

 aniline), washed, dried, and mounted in Canada balsam. 



