l893-] NEW-YORK MICROSCOPICAL SOCIETY. 7 



THE CAUSE OF ASIATIC CHOLERA. 



BY LOUIS HEITZMANN, M.D. 

 {Read October 2ist, 1892.) 



Before Koch's great discovery of the "comma bacillus of 

 cholera Asiatica" many different views were held as to the 

 cause of cholera: first a gas theory, then a miasma theory, a soil 

 theory, and so on, each finding its supporters. In 1884 Koch 

 announced the fact that a "comma bacillus," or rather a " spiril- 

 lum," found only in the intestines of patients and their dis- 

 charges, but neither in the blood nor in any other organ, was the 

 sole cause of the disease. 



Under the microscope the comma bacillus proves to be a 

 small, somewhat curved rod, in the fresh state often forming 

 long curved threads, and hence its name " spirillum." It is best 

 colored with either fuchsin or methylin blue. Microscopical 

 examinations, however, are not conclusive. A number of other 

 bacteria, such as Finkler and Prior's comma bacillus of cholera 

 morbus, Deneke's comma bacillus found in cheese, Gamaleia's 

 Vibrio Metschnikoff found in the intestines of fowls, or Miller's 

 comma bacillus isolated from the mouth, can often not be dif- 

 ferentiated, looking almost exactly alike. 



Cultures are necessary for an absolutely certain differential 

 diagnosis. Koch has shown that his comma bacillus grows on 

 gelatin in an entirely different manner from that of the other 

 comma bacilli. On the plate small colonies develop in from 

 eighteen to twenty-four hours, which have a pale color, darker in 

 the centre, with a slightly uneven contour, and soon look as if 

 studded with particles of glass. These increase in size, and soon 

 the gelatin commences to liquefy in the centre, forming a small 

 funnel, the gelatin having sunk below the level of the surround- 

 ing portions. In a stick culture the same features take place. 

 The funnel in the centre becomes larger and larger, the upper 

 portions apparently becoming filled with an air bubble. The 

 liquefaction of the gelatin goes along slowly, and only by about 

 the sixth day the whole of the upper portion is liquefied. 



All other comma bacilli grow differently on gelatin. Finkler 



