77 
B. CULTURAL CHARACTERS 
1. Gelatin Stab. Draw the culture. (See Figs. 22 and 23.) 
I. Nonliquefying. 
(a) Line of puncture: filiform, uniform needle-shaped growth; 
beaded, succession of small, disjointed colonies; echinulate, 
Pricky; villous, beset with unbranched hair-like extensions; 
arborescent, beset with root-like extensions. 
(b) Surface growth. Same as for colonies on plate cultures. 
II. Liquefying 
(a) Type of liquefaction: crater iform, saucer-shaped; napiform, 
turnip-shaped; infundibuliform, funnel-shaped; saccate, sack¬ 
shaped; stratiform, the liquefaction descending in a horizontal 
plane. 
(b ) Character of the fluid: clear, cloudy, flocculent, granular. 
2. Streak cultures (agar or potato). Draw the agar culture. 
(a) Growth: invisible, scanty, moderate, abundant. 
( b ) Form: filiform, a narrow line; echinulate, growth along line of 
inoculation with toothed or pointed margins; beaded, a suc¬ 
cession of small, disjointed colonies; effused, spreading; 
villous, plumose, arborescent. See Fig. 24.) 
(c) Luster: glistening, dull, cretaceous. 
(d) Optical characters: opaque, translucent, opalescent, iridescent. 
(e) Elevation of growth: same as for plate cultures. 
(/) Topography. 
FIG. 24—AGAR STREAK CULTURES 
1, filiform; 2, echinulate; 3. beaded; 4. effused; 5. villous 
(g) Consistency: slimy, butyrous, of a consistency like butter; 
viscid, growth follows the needle when touched and with¬ 
drawn; coriaceous, growth tough, leathery; brittle, growth dry, 
friable under the needle. 
( h ) Medium discolored. 
3. Beef-broth Cultures 
(a) Growth or no growth. 
( b ) Condition of fluid: clear, cloudy. 
(c) Surface membrane: when formed, color, consistency. 
(d) Sediment: amount, compact, flocculent, granular, viscid. 
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