446 PATHOGENIC BACTERIA. 



is of great interest in comparison with the spirillum of 

 cholera and its related forms. Its morphology is in every 

 particular exactly like that of the cholera spirillum, but 

 its growth is a little more rapid. It grows upon the 

 same culture-media and at the same temperature. The 

 colonies are, however, quite different. 



Upon the second day, when grown upon gelatin 

 plates, the colonies of the Spirillum Berolinensis appear 

 finely granular and paler than those of cholera. The 

 borders are generally smooth and circular. As it be- 

 comes older the colony takes on a slightly brownish 

 color, and may be nodulated or radiately lobulated. The 

 gelatin is very slowly liquefied. 



*<'*&. 





Fig. 99. — Spirillum Berolinensis, from an agar-agar culture; x 1 000 (Itzerott 



and Niemann). 



In puncture-cultures the development takes place along 

 the entire puncture, and causes a gradual liquefaction of 

 the gelatin. 



Upon agar-agar the growth is generally similar to that 

 of the cholera spirillum, but at times is copious, dry, 

 and ragged, and suggests leather by its appearance. 



When introduced intraperitoneally into guinea-pigs 

 the animals die in from one to two days. 



The indol reaction is exactly like that given by cul- 



