CUL 77 VA TION. 409 



not take place, but when it is incubated at a temperature of 

 from 30 to 37 C., a moist layer appears, which assumes 

 a dirty brown colour somewhat like that of the glanders 

 bacillus. It has, however, a greyish-brown rather than a 

 chocolate tint, and moreover the appearance varies some- 

 what in different varieties, and also on different sorts of 

 potatoes. 



In bouillon with alkaline reaction the organism grows 

 very readily, there occurring in twelve hours at 37 C. a 



FIG. 108. Colonies of the cholera spirillum in a gelatine plate ; three 

 days' growth. A, shows the granular surface, liquefaction just com- 

 mencing ; in B liquefaction is well marked. 



general turbidity, while the surface shows a thin pellicle 

 composed of spirilla in a very actively motile condition. 

 Growth takes place under the same conditions equally 

 rapidly in peptone solution (i per cent with .5 per cent 

 sodium chloride added). 



In milk also the organism grows well and produces no 

 coagulation nor any change in its appearance, at least for 

 several days. 



On all the media the growth of the cholera spirillum is 

 a relatively rapid one, and especially is this the case in the 

 peptone solution named and in bouillon, a circumstance of 

 importance in relation to its separation in cases of cholera 

 (vide p. 425). 



Another characteristic, though one not peculiar to this 



