200 IMPOBTANT VABIETIES OF FISSION-FUNGI. 



putrid decomposition. Bact. vulgare (Hauser), L. and N., 

 page 295. 

 (6) Without spontaneous motion and flagella. Gelatin slowly 

 liquefied. 



1. Gelatin colony resembles a bone corpuscle ; delicate center, 



■witb a series of irregular outgrowths. In gelatin stab : 

 nodules, prickly balls, and branches. Bact. erysipelatos 

 suum (Loffler, Schiitz), Migula, page 302. 



2. Gelatin plate similar to the above, or (usually) with very 



delicate, almost invisible colonies. Branches in the stab cul- 

 ture are very delicate and regular. Bact. murisepticum 

 (Fliigge), Migula, page 300. 



Bacterium nitrosomonas (Winogradsky), Lehm. and 

 Neum.i 



Nitrosomonas europaea (Winogradsky). A. P. iv, 

 V ; and Arch, des sciences biolog. de Petersbourg, i, 1892. 

 The morphology is very briefly described. Elliptical and 

 short spindle-shaped, quiet cells, often united in short 

 chains (about 1a broad, and 1.1-1.8^1 long). Upon 

 silicic acid nutrient media the organisms form compact, 

 sharply contoured, brown colonies, from which, after 

 about two weeks, motile swarms wander out (appearing 

 as a pale halo). In fluids there is first a slight sediment ; 

 then after about eight days diffuse cloudiness due to the 

 motile form, which in one or two daj^s again settles quietly 

 to the bottom. 



The organisms thrive only upon inorganic nutrient 

 media : gelatinous silica or water to which is added, in a 

 liter, about 1.0 gm. potassium phosphate, 0.5 gm. mag- 

 nesium sulphate, a trace of chlorid of calcium, 2.5 gm. 

 ammonium sulphate, and some solid magnesium car- 

 bonate. They form nitrite, but no nitrate, from salts of 

 ammonia. 



Growth of the pure culture is difficult, and so far but 

 rarely accomplished. 



Bacterium nitrobacter (Winogradslty). L. and N. 



Literature. — Winogradsky (C. B. L. ii, 415); Winogradsky and 

 Omeliansky (C. B. L. v, 329). The statements of Burri and Stutzer, 



' We select this name because it has many advantages over the un- 

 meaning one of Bact. europteum. 



