260 BACTERIOLOGY 



147. B. rubescens Jordan 



Mass. State Board of Health, 1890, 368. 



Morphology. Bacilli 0.9-4.0 /x; pairs filaments; rods sometimes slightly 



curved. Motility slight. Grow at 37. 

 Gelatin colonies. Punctiform, porcelain-white, round, entire; later of a 



brownish cast. 



Gelatin stab. Slight growth in depth ; on the surface, a porcelain-white bead. 

 Agar slant. Growth smooth, white, glistening, becoming wrinkled after some 



time, with a slight pinkish tinge. 

 Potato. Growth light brown, becoming pink. 



Milk. Not coagulated, alkaline ; in old cultures a pinkish tinge on the surface. 

 Bouillon. Turbid; a surface membrane, viscous ; becoming clear. Nitrates 



not reduced. 

 Habitat. Isolated from sewage. 



CLASS XI. WITHOUT ENDOSPORES. AEROBIC AND FACULTATIVE 

 ANAEROBIC. CHROMOGENIC; PIGMENT BROWNISH BLACK OR 

 GRAY ON GELATIN. 



I. Gelatin liquefied. 



148. B. cyanofuscus (Beijerinck). 

 13.9. B. aeris. 



150. B. ferrugineus (Rullman). 

 II. Gelatin not liquefied. 



151. B. fuscus. 



148. B. cyanofuscus Beijerinck 



Bot. Zeit., XLIX, 1891, Nos. 43-47. 



Morphology. Bacilli 0.2-0.6 /x, and one-half as thick. Cultures in solutions 

 containing 0.5 per cent of pepton become greenish blue brownish black. 

 Gelatin colonies surrounded by a black zone in which crystals are formed. 



Habitat. Isolated from glue, cheese. % 



149. B. aeris 



B.violaceus-sacchari Ager-Dyar: N. Y. Med. Jour., 1894. 



Morphology. Bacilli short, 0.5 : 0.7-1.0 p ; occur singly and in short chains. 



Gelatin. Liquefied quickly. 



Milk. Coagulated. 



Agar slant. Growth thin, translucent ; a greenish fluorescence of the medium. 



Pepton rosolic acid solution. Decolorized. 



