. Laboratory work in bacteriology. Bacteriology. GELATIN AND POTATO MEDIA. 153 tion of a beef-tea into a transparent, solid, and easily lique- :fiable medium. Preparation of Nutrient Gelatin. Place 500 g. of chopped, lean beef in an enamelled jar, such as is shown in Fig. 23. This has a capacity of 1^-2 liters. Now ^d 1000 of tap-water and .stir thoroughly. Immerse the jar in a water- bath, and warm gently,.till the temperature of the meat suspension reaches 55-60°.' Main- tain this temperature .for f-1 hour, stirring frequently. The soluble constituents are thus brought into solution. S
. Laboratory work in bacteriology. Bacteriology. GELATIN AND POTATO MEDIA. 153 tion of a beef-tea into a transparent, solid, and easily lique- :fiable medium. Preparation of Nutrient Gelatin. Place 500 g. of chopped, lean beef in an enamelled jar, such as is shown in Fig. 23. This has a capacity of 1^-2 liters. Now ^d 1000 of tap-water and .stir thoroughly. Immerse the jar in a water- bath, and warm gently,.till the temperature of the meat suspension reaches 55-60°.' Main- tain this temperature .for f-1 hour, stirring frequently. The soluble constituents are thus brought into solution. Special care should be taken not to allow the temperature to rise above 60°, inasmuch as the albuminous sub- stances would then coagulate. By keeping mfk&g^medm" '" these in solution at this stage, they will sub- sequently assist in clarifying the final product, and hence, the addition of a white of an egg will be unnecessary. When the digestion is completed, strain the liquid through muslin and thoroughly squeeze the residue. â The filtrate is dark red in appearance and should measure 1000 ^If this is not the case, add water to make up this volume. To 1000 of the filtrate returned to the clean jar, now add 100 g. of gelatin, 10 g. of dry pepton (Witte's), 5 g. of common salt, and warm at 60°, in the water-bath, with constant stirring, till the gelatin has completely dissolved. The next step is to render the liquid slightly, but distinctly alkaline. 1 A thermo-regulator may be used to maintain a constant temper- ature in the water-bath (see Chapter IX, also Fig. 75).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Novy, Frederick George, 1864- . Ann Arbor [Mich. ] G. Wahr
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