68 BACTERIA 



similar to Asiatic cholera, and hence it is impossible to fulfil 

 the postulate of Koch dealing with animal inoculation. In 

 this respect it is like typhoid. It is, however, provisionally 

 accepted that Koch's bacillus is the cause of the disease. 

 The four or five other bacteria which have from time to time 

 been put forward as the cause of cholera have comparatively 

 little evidence in their support. It is less from these, and 

 more from several spirilla occurring in natural waters, that 

 difficulties of diagnosis arise. 



Some hold that, however many comma bacilli be intro- 

 duced into the alimentary canal, they will not produce the 

 disease unless there is some injury or disease of the wall of 

 the intestine. It need hardly be added that cholera acts, 

 like other pathogenic bacteria, by the production of toxins. 

 Brieger separated cadaverin and putrescin and other bodies 

 from cholera cultures, and other workers have separated a 

 tox-albumen. 



Methods of Diagnosis of Cholera : 



1. The nature of the evacuations and the appearance of 

 the mucous membrane of the intestine afford striking evi- 

 dence in favour of a positive diagnosis. Nevertheless it is 

 upon a minute examination of the flakes and pieces of de- 

 tached epithelium that reliance must be placed. In these 

 flakes will be found in cholera abundance of bacilli having 

 the size, shape, and distribution of the specific comma of 

 cholera. The size and shape have been already touched 

 upon. The distribution is frequently in parallel lines, 

 giving an appearance which Koch described as the " fish-in- 

 stream arrangement." This distribution of comma bacilli 

 in the flakes of watery stools is, when present, so character- 

 istic of Asiatic cholera that it alone is sufficient for a definite 

 diagnosis. But unfortunately it is not always present, and 

 then search for other characters must be made. 



2. The appearance of cultivation on gelatine, to which 

 reference has been made, is of diagnostic value. 



