316 BACTERIOLOGY 



19. Ps. ochracea (Zimmerman) 



B. ochractus Zimmerman: Bak. Nutz u. Trinkwasser, Chemnitz, 1890. 



Morphology. Bacilli 0.5-0.8 : 1.2-3.6 p. Stain by Gram's method. Flagella 

 polar. 



Gelatin colonies. Deep: round, small, light yellowish. Surface: at first coli- 

 like, becoming slightly fringed on borders, becoming liquefied and de- 

 pressed ; a pellicle on the surface of a grayish yellow or deep yellow color, 

 often with a reticulate structure. Microscopically, brownish, granular, 

 often warty. 



Gelatin stab. On the surface a yellowish yellowish gray layer, which sinks, 

 becoming a funnel and later a cylindrical liquefaction, with a pale yellow 

 or ochreous sediment. 



Agar slant. A thin yellowish gray ochreous expansion. 



Bouillon. Weakly turbid, with a slight pellicle, and much sediment. Indol 

 positive. H 2 S produced. 



Milk. Not coagulated, somewhat slimy. 



Glucose bouillon. No gas. 



Potato. Growth ochre-yellow. 



Habitat. Water. 



20. Ps. campestris (Pammel) Smith 



B. campestris Pammel: Bull. 27, Iowa Ag. Expt. Sta., 1895, 130. 

 Ps. campestris Smith : Centralblatt f. Bakteriol., 2te Abt., Ill, 1897. 

 B. campestris Russell : Wis. Ag. Expt. Sta., Bull. 65, 1898. 



Morphology. Bacilli 0.4-0.6: 1-2 \n\ occur singly and in chains. Motility 

 active. Stain uniformly with Loffler's methylene blue ; stain irregularly 

 with Ziehl's carbol-fuchsin. Decolorized by Gram's method. 



Gelatin colonies. Deep: round, sharp, darker than surface growths, concen- 

 tric. Surface: in 3-4 days 1 mm., moist, glistening, raised, light yellow. 

 Microscopically, round, entire, centres darker, finely granular, sometimes 

 radiately streaked. In 12-15 days the surface colonies begin to liquefy. 



Agar colonies. Deep: lenticular irregular, dark, granular, concentric. Sur- 

 face: 1-4 mm., thin, moist, glistening, translucent, light yellow olive. 

 Microscopically, thicker and denser in centre, concentric. 



Agar slant. At first an elevated streak, becoming spreading, thinner, and 

 somewhat translucent ; rich golden yellow. 



Gelatin stab. Slight growth in depth, spreading slightly at the surface. In 

 7-10 days a slight liquefaction under the latter, and a pit due to evapora- 

 tion. Liquefaction extends laterally, very slowly, becoming stratiform. 



