THE CLASSIFICATION OF BACTERIA 345 



Varieties. — Spirillum undula-minus and Spirillum undula-majus of Zett- 

 now-Kutscher : Centralblatt f. Bakteriol., XVIII, 614; XIX, 393. One- 

 third larger than the above. Grow well on gelatin and agar. 



6. Spirillum concentricum Kitasato 



Centralblatt f. Bakteriol., Ill, 72, 1888. 



Morphology. Bacilli 0.5 : 1.0-8.0 /a; spiral forms, ends pointed. Bundles of 



polar flagella at one or both poles. 

 Gelatin colonies. Round, grayish, concentric. 

 Gelatin stab. Slight growth in depth ; on the surface, growth, thin, veily, 



spreading. 

 Agar slant. Growth thin, adherent. 

 Potato. No growth at 2o°-y]°. 

 Bouillon. Turbid ; becoming clear, with a sediment. 

 Milk. Not coagulated. H^S negative. Indol negative. 

 Habitat. Isolated from putrid blood. 



7. Spirillum tenue Ehrenberg 



Die Infusionsthierchen als voUkommene Organismen, 1838. 



Morphology. Bacilli 0.8 /a wide and 4-15 /x long, of 2-5 undulations, wave 



length and amplitude, 2-3 ju,. Bundles of flagella at either pole. Spores 



negative. 

 Gelatin colonies. Deep: round, entire, finely granular, yellowish. Surface: 



round, thin, yellowish. 

 Gelatin stab. In depth, growth filiform ; on the surface, a yellowish layer, 



and a slow liquefaction, with a bubble of gas. 

 Potato. No growth. 

 Bouillon. Turbid, with a thick membrane. See Bonhofi", Hyg. Rundschau, 



VI, 351. Kutscher, Centralblatt f. Bakteriol., 2te Abt., I. 

 Habitat. Putrefying vegetable infusions, etc. 



8. Spirillum rubrum v. Esmarch 



Centralblatt f. Bakteriol., I, 1887, 225. 



Morphology. Bacilli short spirals 0.6-0.8: 1.0-3.2 /a, with i — 2 — 3 screw 

 twists when grown in gelatin or agar; in bouillon, longer forms which 

 are twice as thick as Msp. comma. The shorter spirilla are very motile, the 

 longer ones only slightly so. There are glistening spots in the rods like 

 spores, but which do not stdn. Stained by Gram's method. Flagella 

 in bundles at the poles. 



