CULTIVATION. 407 



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 epi- 

 thelium, the intestinal contents being a comparatively 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. 425). 



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 gelatine. 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 appearance : 

 there is at the surface the bubble-shaped depression ; below 

 this there is a funnel-shaped area of liquefaction, the fluid 

 being only slightly turbid, but covered on its surface with 

 a more or less complete pellicle, and showing at its lower 

 end thick masses of growth of a more or less spiral shape 

 (Fig. 107). The liquefied portion gradually tapers off down- 

 wards towards the needle track. (This appearance is, 

 however, in some varieties not produced till much later, 

 especially when the gelatine is very stiff, and, in other 

 varieties which liquefy very slowly, may not be met with at 



