Bacillus Ruber of Kiel, Breunig. 



B. RUBER BALTICUS. 



ORIGIN. Drinking water of Kiel. 



FORM. Thick rods two to three times as long as wide; 

 at times, may be much longer. 



MOTILITY. It is somewhat motile, and the motion de- 

 pends on presence of oxygen. 



SPORULATION. This has not been observed. 



ANILIN DYES. Stain readily. 



GROWTH. Rapid and abundant. 



Gelatin plates. Deep colonies are oval, pale yellow, with wavy or 

 even border. The surface colonies are blood-red in color, spread 

 rapidly, and have a sinuous border; are surrounded by a clear zone, 

 and liquefy gelatin. Z 



Stab culture. Growth and liquefaction take place along* the line 

 of inoculation. The fluid becomes strongly colored, and gas may 

 form in the deeper layers. 



Streak culture. On agar, at 30-35, the thick, slimy growth is at 

 first a pale rose, and later becomes a brick-red. On potato, at 30-35, 

 it develops rapidly, forming- a purple red growth. At lower tem- 

 peratures the color is very marked-; at first it is orange, later carmine 

 red. 



Milk. At 35, coagulation takes place in 24 hours, without a 

 trace of coloration, due to rapid growth and production of acidity. 

 At ordinary temperature the coagulation takes place slowly, and the 

 fluid gradually colors. 



OXYGEN REQUIREMENTS. It is a facultative anaerobe, but 

 requires oxygen to form the pigment. 



TEMPERATURE. Grows from 10 to 42. The optimum is 

 30-35, and above this the growth ceases to be colored. 

 Direct insolation kills it in five hours. An exposure of 

 three hours does not kill, but alters it so that it no longer 

 produces the pigment, i. e. , becomes attenuated. 



BEHAVIOR TO GELATIN. It liquefies gelatin quite rapidly. 



AEROGENESIS. Gas bubbles form in the gelatin. 



PIGMENT PRODUCTION. This weakens considerably on cultiva- 

 tion, and almost colorless varieties are met with. The color may be 

 restored by successive culture on potato, and by growth at 15. It is 

 soluble in alcohol, but not in chloroform. The pigment is turned 

 red by acids, and is decolored by alkalis. It is discolored by zinc dust 

 and glacial acetic acid distinction from that of B. prodigiosus. 



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