402 CHOLERA 



aniline stains, though Lofner's methylene-blue or weak carbol- 

 fuchsin is specially suitable. They lose the stain in Gram's 

 method. 



Distribution within the Body. The chief fact in this con- 

 nection 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 

 Lieberkiihn, and may be seen lying between the basement 

 membrane and the epithelial lining, which becomes loosened by 

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

 tissue beneath, and never penetrate deeply. Along with these 

 changes there is congestion of the mucosa, especially around the 

 Peyer's patches and solitary glands, which are somewhat swollen 

 and prominent. In some very acute cases the mucosa may show 

 general acute congestion with a rosy pink colour but very little 

 desquamation of epithelium, the intestinal contents being a com- 

 paratively clear fluid containing the spirilla in large numbers. 

 In other cases of a more chronic type, the intestine may show 

 more extensive necrosis of the mucosa and a considerable 

 amount of haemorrhage into its substance, along with formation 

 of false membrane at places. The intestinal contents in such 

 cases are blood-stained and foul-smelling, there being a great 

 proportion of other organisms present besides the cholera spirilla 

 (Koch). 



Cultivation. (For Methods, see p. 413.) 



The cholera spirillum grows readily on all the ordinary media, 

 and with the exception of that on potato, growth takes place at 

 the ordinary room temperature. The most suitable temperature, 

 however, is that of the body, and growth usually stops about 

 16 C., though in some cases it has been obtained at a lower 

 temperature. 



Peptone Gelatin. On this medium the organism grows well 

 and produces liquefaction. In puncture cultivations at 22 C. a 

 whitish line appears along the needle track, at the upper part of 

 which liquefaction commences, and as evaporation quickly occurs, 

 a small bell-shaped depression forms, which gives the appearance 

 of an air-bubble. On the fourth or fifth day we get the following 



