CHOLERA 173 



The ' comma ' bacillus produces sulphuretted hydrogen 

 in broth cultures. In examining a sample of stool sus- 

 pected to be choleraic, the microscopic appearance alone 

 is often sufficient to establish its true character, while in 

 other cases the culture test may yield positive results when 

 the microscopic appearance is doubtful or negative. In 

 true cholera the ileum presents a characteristic appearance, 

 the mucous and serous coats being congested. 



To establish the identity of an organism with Koch's 

 'comma,' it should be found to resemble it (1) morpho- 

 logically ; (2) culturally ; (3) in its chemical products. 



' Comma ' bacilli straight from the stool are short, thick, 

 curved rods, about 3"0 mm. long and 0"3 mm. thick. 

 They also possess three or four fiagella, while after sub- 

 culture they are found to have only one. It is also a 

 remarkable fact that the flagella of organisms fresh from 

 the stool stain readily with the ordinary aniline dyes, while 

 the flagella in the organisms taken from a culture require 

 mordanting before they will take the stain. On repeated 

 subculture, the organism grows out into longer and thinner 

 rods, bearing very little resemblance to bacilli straight 

 from the stool ; hence it materially follows that cultures 

 met with in bacteriological laboratories are not always 

 typical. 



In examining the body of a patient who had died from 

 supposed Asiatic cholera, the condition of the ileum should 

 first be noted, and a portion preserved for examination by 

 being ligatured at both ends, and then placed in a tightly- 

 corked bottle, if the examination cannot be made at once. 

 In acute cases the mucous and serous coats are found 

 greatly congested, and the epithelium is usually to a great 

 extent detached in the shape of flakes. , 



The flakes may contain large numbers of the ' commas,' 

 and it is frequently possible to report positively at once as 



