Essentials of bacteriology; being a concise and systematic introduction to the study of bacteria and allied microörganisms . at one end. Old agar cultures showstraight forms; S-shaped forms not uncommon, made of twovibrios end to end (Fig. 64). Properties.—^The spirilla are very motile; liquefy are easUy affected by heat and dryness. Spores havenot been found. Growth.—^At ordinary temperatures on all nutrient media that have an alkaline or neutral reaction. Strongly aerobic. Colonies, Gelatin.—After twenty-four hours, small white points which gradually come to the surface, the ge
Essentials of bacteriology; being a concise and systematic introduction to the study of bacteria and allied microörganisms . at one end. Old agar cultures showstraight forms; S-shaped forms not uncommon, made of twovibrios end to end (Fig. 64). Properties.—^The spirilla are very motile; liquefy are easUy affected by heat and dryness. Spores havenot been found. Growth.—^At ordinary temperatures on all nutrient media that have an alkaline or neutral reaction. Strongly aerobic. Colonies, Gelatin.—After twenty-four hours, small white points which gradually come to the surface, the gelatin being CHOLEEA BACTERIA 149 slowly liquefied, a funnel-shaped cavity formed, holding thecolony in its narrow part, at the bottom, and on the fifth dayall the gelatin is liquid. If the colonies of three days growthare placed under microscope, they appear as if composed ofsmall bits of frosted glass with sharp, irregular points. Stab-culture.—^After thirty hours a growth can be distin-guished along the needle-track, and on the surface a littlecavity is formed, filled by a bubble of air, and this liquefaction. Fig. 65.—Cholera colonies after thirty hours (Xioo) (Frankel and Pfeifier). proceeds untO, on the sixth day, it has reached the sides ofthe tube, tapering, funnel-shaped, to the bottom of the several weeks the spirilla are found in little collectionsat the bottom of the fluid gelatin. In eight weeks the bacillihave perished. Agar.—Stroke cultures. A shiny white layer which lastsmany months. Alkaline Agar.—Plates at 37° C. Flat discs, transparent,grayish blue. 150 ESSENTIALS OF BACTEEIOLOGY Potato.—^A yellow, honey-like, transparent layer if thepotato is kept at animal heat. Bouillon.—^A wrinkled scum is soon formed in spirilla live well and grow in sterilized milk and sterilizedwater, remaining virulent in the latter for many months.
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisherphila, bookyear1913
