13 



ment moidore; mais actuellement je n'en saurais dessiner une mo- 

 nographie precise: mes recherches sur ce micro-organisme datant 

 de plus de 10 ans." (1901). 



I have completed Miquel's description as follows: 

 Morphology, a rodlet 23 /LI in length, often in chains of 

 several bacilli, non-motile, sporeless. Gelatin colonies, 48 hours, 

 small, irregular, finely granular, with well defined edges ; 72 hours, 

 show a peculiar corrugated, overlapping growth; the next day pig- 

 ment appears at the centre, and later they become deep violet red. 

 In gelatin stab, a red surface colony and a white needle track 

 growth; no liquefaction. 24 hours, surface colonies on agar 

 show a peculiar lined and cracked appearance under low power; 

 in 48 hours they are tinged red, and later look like B. prodi- 

 giosus colonies. Agar streak shows green luster and is like B. 

 prodigiosus or B. ruber kiliensis. Potato violet, red line 

 in 24 hours, later darker, often green luster. Does not spread 

 on potato. Blood serum not liquefied. Milk, no change except 

 pigmentation. Gas, 45 | of tube length in dextrose bouillon only, 

 79 / of gas C0 2 . Oxygen and temperature relations, like B. pro- 

 digious. Nitrates reduced to nitrites. No characteristic odor. 



B. r ubricus (n. sp.). 



In the autumn of 1901 three cultures were isolated in this 

 laboratory (University of Chicago) from the Mississippi and the 

 Missouri Rivers, which produced red pigment but showed marked 

 differences from B. prodigiosus and the cultures previously 

 described. These cultures do not grow rapidly, and the pigment 

 appears very slowly, the color beginning as pink or salmon pink, 

 and not attaining the characteristic brilliant red for some weeks. 

 Morphology, a small, slender, non-motile bacillus. Colonies, gela- 

 tin and agar, slow growing, small, round, non-characteristic, under 

 low power finely granular; color, yellow orange, deepening to red. 

 When first isolated, began to liquefy gelatin very slowly in ten 

 days. After a year's cultivation, the power of liquefying ordinary 

 gelatin had entirely disappeared. Agar slant, when dry and 

 growth limited, may develop bright red pigment in a few days; 

 when moist and spreading, may remain white or light pink for 

 weeks, gradually deepening in color. Potato slight or no growth. 

 Bouillon, cloudy, with pink pellicle. When first isolated, milk un- 

 affected; later, litmus milk cultures showed marked alkalinity. No 

 gas, nitrate not reduced, aerobic. May grow at 37 C, but better at 

 room temperature. 



B. rufus (n. sp.). 



Two cultures, much like B. r ubricus, were isolated at about 

 the same time and place. In pigment and in manner of develop- 

 ment this organism was hardly distinguishable from B. r ubricus, 

 but differed in showing luxuriant growth on potato, and in not 

 losing its power of liquefying gelatin slowly but completely. Milk, 

 unchanged or slightly alkaline in 15 days. 



