The bacterial diseases of respiration, and vaccines in their treatment / By R. W. Allen.

  • Allen, R. W., 1876-1921.
Date:
1913
Catalogue details

Licence: Public Domain Mark

Credit: The bacterial diseases of respiration, and vaccines in their treatment / By R. W. Allen. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    plates can thus be prepared from one finger tip. Any effort to conserve the agar is to be strongly deprecated, for frequently plates require three days' incubation, at the end of which time the unduly thin plate will have so dried in the incubator as to be ill-adapted for bacterial growth ; the above quantity, lo c.c, is the least which should be used for a plate of 3I in. in diameter. Other media which are necessary for the more or less complete study of this question are : Agar (+ 10 Eyre's scale). Serum-agar (blood serum one part, 2 per cent, agar three parts). Acid-blood agar (blood agar made as above except that to the agar [+10 Eyre's scale] i per cent, hydrochloric acid has been added). Dorset's egg medium (take fresh hen's egg, sterilise shell, break, mix yolk and white thoroughly, add distilled water to 25 per cent., pour into sterile test-tubes one inch in diameter, avoiding all bubbles, slant, heat in inspissator at 85° C. for half an hour on each of three successive days). Peptone broth— Peptone water (0*5 per cent, peptone solution). Sugar media (o5 per cent, peptone water to which 2 per cent, of the various sugars has been added ; of these it is well to have dextrose, levulose, saccharose, lactose, maltose, galactose, mannite, dextrin, sor- bite, dulcite, inulin). Acid-blood-peptone broth,/.^. 10 c.c. peptone broth, i c.c. blood citrate mixture, to which have been added o5 per cent, of lactic acid and o5 per cent, potassium tartrate (for mouth organisms). Special media such as MacConkey's are at times useful, and a contrivance for anaerobic incubation may be necessary. The preliminary examination of stained srhears will enable the decision to be made as to what media are to be employed, the use of a blood agar plate being obligatory: it will also indicate how much material is to be employed for insemination purposes. As a rule the amount of secretion taken up by a platinum loop one tenth of an inch in diameter will suffice; with this the blood agar plate is lightly streaked, the last stroke being made parallel to, but at the margin of the plate opposite to the first. In this way discrete colonies are certain to be secured; if they develop too thickly on the first few streaks they will be sufficiently separate on some of the subsequent ones. The plate is incubated at ^y° C. for twenty-four hours and examined by direct observation and by means of stained films. It is then returned to the incubator for another twenty-four hours, for some bacteria such as B. influenza, B. Bordet-Gengou, may have developed but slightly by the end of the first day, but will be easily seen by the end of the second.