11 



B. rutilus (n. sp.). 



This organism was isolated in November, 1899, from the Illinois 

 River. One ccm of water was incubated for 24 hours in 0,55 carbol 

 broth, then plated in litmus lactose agar, where such a production of 

 pigment occurred that the plate was brilliantly colored. The red pig- 

 ment form grew luxuriantly upon isolation, arid, since it differed from 

 B. prodigiosus and from the others of the series, is here de- 

 scribed as a new species. Its vigor of growth and pigment pro- 

 duction have been slightly lessened by two years of cultivation 

 upon laboratory media. Its points of difference are as follows: 



A short, actively motile bacillus, slightly larger on all media 

 than B. prodigiosus, but smaller than B. ruber balticus. 

 Gelatin, growth and liquefaction rapid, little pellicle, the whole 

 liquid vivid red. When first isolated, agar plate colonies always 

 showed pseudopodia-like ramifications; later, branching more rare, 

 or only on plates from old cultures. Growth and pigment best on 

 acid agar. No metallic luster ever seen on agar or potato. In 

 acid bouillon, the whole liquid colored red, no pellicle. The pre- 

 sence of dextrose and lactose increases the pigment, that of sucrose 

 does not. Milk, acid and coagulated in 24 hours, later peptonized 

 at 35 C. Gas production, in dextrose and sucrose bouillon, when 

 first isolated, 90 | of tube length, 65 % of this C0 2 . Later, 50 / 

 of tube length, all C0 2 . Nitrates reduced only to nitrites. Odor, 

 like B. prodigiosus. 



B. amyloruber (n. sp.). 



An organism which differed from B. prodigiosus, B. ruber 

 balticus etc., in pigment and in some other characters, was iso- 

 lated from Mississippi River water in 1901 ; because of its ability 

 to grow actively upon starchpeptone media it has been given the 

 above name. After passing through a summer upon neutral agar 

 the character of its growth was somewhat changed, tending to a 

 thin crusty or granular growth instead of one soft and luxuriant. 

 The pigmentation on ordinary media has undergone no deterioration, 

 remaining deep violet red. The chief points of deviation from the 

 forms already described are as follows: 



Upon ordinary media the pigment is deep violet red, taking 

 orange color only on alkaline agar. Sugar free bouillon, little pig- 

 ment; sugar bouillon, colored deep violet red. Milk, peculiar; at 

 first, no change; later, a violet red coloration; after 15 days, a 

 tine red and white sediment of pigment granules and precipitated 

 casein, but no coagulation and no peptonization. No gas is evolved 

 in any sugar bouillon. Nitrates, reduced to nitrites. 



B. fuchsinus (Boekhout and de Vries). 

 This name has been given to two different organisms; 1) to 

 a "new chromogenic bacillus" described by Boekhout and 

 de Vries in 1898 (60), and 2) to the red bacillus described but un- 

 named by Lustig in 1893 (8), named by Migula in 1900 (10). 

 Lustig's organism, which he described very completely, differs 

 morphologically from B. prodigiosus in that it is a rodlet two 



