140 Marshall Ward. — On the Characters , or 
(/3) Colonies colourless, forming thin films on plates, &c. 
(i) Odourless. 
Bacillus acidi-lactici. 
B. typhosus (Eberth). 
Bacterium coli commune , &c. 
(ii) Distinctly odorous. 
Bacillus ureae. 
B. pyogenes foetidus , &c. 
(■y) Colonies form white ‘ nail-head projections '* on 
plates, &c. 
(i) Colonies microscopically small, with granular 
margins. 
Bacterium pneumoniae , &c. 
(ii) Colonies with smooth borders. 
Bacterium lactis aerogenes, &c. 
(S) Colonies branched irregularly, not circumscribed. 
Bacterium Zopfii. 
B. Colonies colourless, but the gelatine near is stained. 
(a) Staining greenish. 
Bacillus erythrosporus , &c. 
(j8) Staining blue or greyish brown. 
Bacillus cyanogenus. 
(y) Staining violet. 
Bacillus janthinus. 
C. Colonies cream-coloured. 
Bacillus of septic pneumonia. 
D. Colonies yellow. 
Bacillus luteus. 
B.fuscus , &c. 
II. The nutrient gelatine is liquefied. 
A. Colonies white ; nutrient substratum not coloured. 
(a) Colonies branched, or with processes. 
(i) Colonies not motile. 
Bacillus anthracis. 
B. ramosus liquefaciens . 
B. subtilis, &c. 
(ii) Colonies motile and swarming, rapidly lique- 
fying the gelatine. 
Proteus vulgaris, & c. 
