A laboratory guide in elementary bacteriology / by William Dodge Frost.

Date:
1903
Catalogue details

Licence: In copyright

Credit: A laboratory guide in elementary bacteriology / by William Dodge Frost. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    26/426 page 6
    Special Directions. All glassware prepared in 1. is to be sterilized for one hour at 150° C. The small pipettes should be placed in brass tubes, provided for the purpose, and also sterilized. EXERCISE 4. PREPARATION OF BOUILLON. General Directions. Any one of the three methods (A, B or C) may be used. They are arranged in order of preference, but method C is the most convenient, and hence most used. A. B. a. From 500 grams (1 % lbs.) of lean a. Ditto, beef remove tlie fat and connective tis- sue and mince (or use Hamburg steak). b. Add 1 liter of distilled water and after shaking thoroughly set in ice chest for 12 to 24 hours. c. Squeeze through a cloth and add enough distilled water to filtrate to make 1 liter and place in vessel to cook. b. Add 1 liter of distilled water. c. Place in ves- sel for cooking, then cook for y2 hour at about 70° C., filter through paper and make up to 1 liter. C. a. Weigh out three grams of beef extract (such as Lie- big’s). b. Add 1 liter of distilled wa- ter. c. Place in vessel for cook- ing. d. Add to any of the above solutions: 1% (10 gms.) peptone (Witte) and Y>% (5 gms.) common salt (NaCl), then weigh solu- tion, with vessel, so that the water which is subsequently driven off in cooking can be accurately replaced. Cooking may be done either in a flask which is heated in a water- bath or sterilizer, double-walled boiler, or rice-cooker. In case a rice- cooker is used a 50% solution of calcium chloride should be placed in the outer vessel instead of water as by this means the contents of the inner vessel can be brought to a rapid ebullition, something impossible by the use of water alone. e. Heat, not above 60° C., until ingredients are in solution, then restore the water lost by evaporation. f. Neutralize. This is a very important step and calls for great care. Of the following methods, A is more accurate and should be employed for special or research work. For ordinary routine work B may be employed.
    digitised image 1
    digitised image 2
    digitised image 3