474 



SPIRILLUM FIXKLER AND PEIOR. 



Puncture 

 cultivations. 



Growth on 

 potatoes. 



and then again a darker marginal zone. The young 

 colonies can be distinguished from those of cholera 

 bacilli without any difficulty by means of the above 

 mentioned characters ; at a later stage, more especially 

 when the cholera colonies are older than Tinkler's, the 

 diagnosis is not so easy, but it can always be made when 

 a considerable number of colonies are examined. At a 

 still later period Tinkler's bacilli liquefy the gelatine 

 very energetically ; a funnel, 1 cm. in diameter or 

 more, is formed, and as a rule the whole plate very 

 soon becomes entirely liquid. 



In puncture cultivations in gelatine Tinkler's bacilli 

 arc also characterised by the greater energy with which 



they liquefy the gelatine. 

 When cultivated under the 

 same conditions as Koch's 

 bacilli they lead, even with- 

 in 48 hours, to the forma- 

 tion of a comparatively wide 

 sac-like tube which is filled 

 with muddy fluid ; after 24 

 hours more the liquefaction 

 has usually reached the wall 

 of the test-tube and has in- 

 volved the uppermost por- 

 tion of the gelatine, while 

 the lower end of the sac has 

 correspondingly increased 

 in breadth. When culti- 

 Fig -i 2 &~ C ' Ultivatio \ of .^ inklcr vatedou nutrient agar the 



and Prior s comma bacillus. . 



c, 2 days old. d, 4 days old. bacilli form yellowish-white 



deposits without liquefac- 

 tion, and without any definite characters. Blood serum 

 is rapidly liquefied. On potatoes kept at the tem- 

 perature of the room they form within 48 hours a 

 greyish-yellow gelatinous coating, which is marked oft' 

 from the substance of the potato by a white border. 

 This growth on potatoes forms the most striking con- 

 trast to the behaviour of Koch's comma bacilli, which do 

 not grow at all on potatoes at the ordinary tempera- 



