406 CHOLERA. 



clubbed at their extremities, and also showing irregular 

 swellings along their course. Others are short and thick, 



and may have the 

 appearance of large 

 cocci, often staining 

 faintly. All these 

 changes in appear- 

 ance are to be 

 classed together as 

 involution forms. 



Staining. Cholera 

 spirilla stain readily 

 with the usual basic 

 aniline stains, 

 though Loffler's 

 methylene - blue or 

 weak carbol-fuchsin 



FIG. 106. Cholera spirilla from an old i s specially suitable, 

 agar culture, showing irregularities in size and -TO.- i n __ f u_ t 

 shape, with numerous faintly-stained coccoid x ne Y J 

 bodies involution forms. in Gram's method. 



Stained with fuchsin. x 1000. Distribution 



within the Body. 



The chief fact in this connection is that the spirilla are 

 confined to the intestine, and are not present in the 

 blood or internal organs. This was determined by 

 Koch in his earlier work, and his statement has been 

 amply confirmed. In cases in which there is the 

 characteristic "rice-water" fluid in the intestines, they 

 occur in enormous numbers almost in pure culture. The 

 lower half of the small intestine is the part most affected. 

 Its surface epithelium becomes shed in great part, and the 

 flakes floating in the fluid consist chiefly of masses of 

 epithelial cells and mucus, amongst which are numerous 

 spirilla. The spirilla also penetrate the follicles of Lieber- 

 kiihn, and may be seen lying between the basement mem- 

 brane and the epithelial lining, which becomes loosened by 

 their action. They are, however, rarely found in the 

 connective tissue beneath, and never penetrate deeply. 



