CHAPTER: VIIL. 
DETERMINATION OF SPECIES. 
I. MORPHOLOGY AND LIFE-HISTORY OF A SPECIES. 
THE following points in the morphology and life- 
history of any form of bacterium must be known 
before it can be fully described or assigned a place 
in any particular species.' 
I. SouRcE AND HapsiratT. 
II. MoRPHOLOGIC CHARACTERS. 
1. Form. 
2. Dimensions. 
3. Manner of grouping’ and arrangement in the 
growths. 
4. Staining powers: (a) with aqueous stains; (6) by 
Gram’s method. 
. Presence or absence of capsule. 
. Presence or absence of flagella (motility). 
. Spore-formation. 
. Tendency to pleomorphism. 
. Involution and degeneration forms. 
III. BroLoGic CHARACTERS. 
A. Cultural characteristics, mode of growth in and 
upon— 
Oo ON AN 
- Bouillon. : 
. Gelatin plates (single colonies, surface and deep), 
. Gelatin-tubes. 
. Agar plates (single colonies, surface and deep). 
PwNH 
1 These are the points recommended by the Committee 
of Bacteriologists of the American Public Health Associa- 
tion. 
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