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4. Milk Cultures. Draw the litmus milk culture. 
I. Curd formed. 
(a) Time required to curdle. 
(b) Character of curd: hard or soft, solid or porous, changed or not, 
when boiled. 
(c) Whey: amount, clear or turbid. 
(d) Reaction to litmus. 
(c) Digestion of curd (examine plain milk culture): time required, 
reaction to litmus, solution cloudy or clear. 
(/) Gas bubbles. 
(ff) Odor. 
II. Digestion without formation of curd. 
III. No visible change even after boiling. 
5. Plate Cultures. 
I. Surface colonies. Naked eye appearance. (See Fig. 25.) Draw a 
colony. 
FIG. 25—NAKED EYE APPEARANCE OF COLONIES 
A, punctiform; B, circular; C, oval; D, spindle-shaped; E, conglomerate; F, ameboid; G, rhizoid; 
H, curled; I, myceloid; J, filamentous. 
(a) punctiform, too small to be defined by the naked eye; circu¬ 
lar: oval; spindle-shaped; conglomerate; an aggregate of similar 
