SPIRILLUM CHOLERA ASIATICS. 



429 



The comma bacilli can be readily cultivated in very Behaviour of 

 various nutrient media. On gelatine plates they form ^iciilH^ 

 after 24 hours at 22 C. very minute white points which cultivations, 

 under a low power present the appearance of small round 

 whitish-yellow refracting discs, without any sharp out- 

 line, and with an ir- 

 regular and wavy 

 margin. These discs 

 become gradually 

 larger, they retain their 

 faint yellow colour, 

 which only becomes a 

 little darker at the 

 central part, but with- 

 out any formation of 



Fig. 122. Colonies of cholera spirilla 

 X 100. 



zones, and the irregu- 



a, after 20 hours. 

 &, 30 



c, 36 



d, 48 



At c there is commencing liquefaction 

 of the gelatine ; at d the colony has 

 sunk to the bottom of the funnel- 

 shaped liquefied area. 



lar outline becomes 



more distinct; the same irregularity and roughness ex- 

 tends over the whole surface of the spherical colony, and 

 as a consequence it pre- 

 sents a distinctly granular 

 or furrowed appearance. 

 The highly refracting 

 character of these colonies 

 gives them a clear shiny 

 appearance, and the sur- 

 face of the plate looks as if 

 it had been sprinkled over 

 with small bits of glass. 

 The gelatine now begins 

 to undergo gradual lique- 

 faction ; even with the 

 naked eye the gelatine on 

 the plates appears some- 

 what depress ed at the parts 



.!,,., n ,1 -i -,. Fig. 123. Puncture cultivation of 



where the colonies lie ; a KocVs comma bacillus, 



small, sharply - defined , two days old. 



funnel, containing fluid, 



is gradually formed at this place, the colony lying at the 

 bottom of the funnel. The liquefaction only extends 



Microscopical 

 appearance of 

 the colonies in 

 nutrient jelly. 



