44 A MANUAL OF BACTERIOLOGY 



pointed margins (Fig. 22, B) ; beaded, a succession 

 of small, disjointed colonies (Fig, 22, C); effused, 

 spreading (Fig. 22, Z>); villous, plumose, arborescent 

 (Fig. 22, E). 



c. Luster : glistening, dull, cretaceous. 



d. Optical characters : opaque, translucent, opalescent, 

 iridescent. 



e. Odor: absent, decided. 



f. Elevation of growth 



r same as for plate cultures. 



g. Topography 



h. Consistency : slimy ; butyrous, of a consistency like 

 butter ; viscid, growth follows the needle when 

 touched and withdrawn ; coriaceous, growth tough, 

 leathery ; brittle, growth dry, friable under the 

 needle. 



i. Medium discolored. 



3. Beef -broth cultures. 



a. Condition of fluid : clear, cloudy. 



b. Surface membrane : when formed, color, consistency. 



c. Sediment : amount, compact, flocculent, granular, 

 viscid. 



d. Reaction to litmus. 



e. Odor. 



4. Milk cultures. 



I. Curd formed. 



a. Time required to curdle. 



b. Character of curd : hard or soft, solid or perforated, 

 changed or not, when boiled. 



c. Whey : amount, clear or turbid. 



d. Reaction to litmus. 



e. Digestion of curd : time required, reaction to litmus, 

 solution cloudy or clear. 



f. Gas bubbles. 



g. Odor. 



II. Digestion without formation of curd. 

 III. No visible change even after boiling. 



