The essentials of practical bacteriology : an elementary laboratory book for students and practitioners / by H. J. Curtis.

  • Curtis, Henry J.
Date:
1900
Catalogue details

Licence: In copyright

Credit: The essentials of practical bacteriology : an elementary laboratory book for students and practitioners / by H. J. Curtis. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    39/314 (page 21)
    OHOOL OF MPDICl TO MAKE AN E^M^^SR^I^^CT^TUfl^u £ Q3 21 gelatine in a water bath (see fig. 18, p. 24), and when the temperature, as indicated by the thermometer, is at, or just below, 37° C, inoculate it (as if it were a tube of broth) with a loopful of growth from a tube containing B. coli communis. Holding the tube vertically between the palms of the two hands, rotate steadily; avoid making bubbles by any vigorous shaking up. Eapidly solidify by placing under a stream of water from the tap, or in a narrow jar of cold Avater. After capping the tube, incubate at 20° C. Agar-agar, and (better still) sugar-agar, may also be used in making shake cultures of B. coli, or, in the case of the anaerobes, the bacillus of mahgnant oedema, and of quarter-evil, &c. The temperature, after thoroughly hquefying the agar (preferably in the autoclave at 120° C), must be cooled down to about 42° C. in a large water bath full of water. The inoculation with the growth, and subsequent rotation of the tube whilst in the vertical position, must be more rapidly done than when gelatine is used, owing to the rate at which agar-agar solidifies below about 40° C. When capped, the tube is kept at 37° C. Esmarch's roll-tube.—This was formerly much used for separating mixed cultures or counting the colonies in a sample of water. Its a\ sit, 'j 6% e. 0 ' • c r <: Fig. 13.—esmaech tube-cultdbe or ' eoll-ttjbe ' a, india-rubber cap ; h, b, b, longitucliu.il line drawn on gl«ss ; c, c, c, transverse lines on glass to facilitate the counting of the colonies. [PranKland.] use has been largely given up in favour of the far more convenient petri-dish preparation. To make an Esmarch's roll-tube.—Gelatine is the easier to mani- pulate, though, with the precautions already mentioned, agar may be equally well employed for making roll-tubes. It is essential that only a small quantity of gelatine should be used—about enough to occupy the bottom half-inch of the 5 x f inch tube (about 1^ c.c). The gelatine is either first inoculated by stabbing the solid medium, and then melted at or below 37° C, or melted and then inoculated at, or below, the body temperature. The tube is capped, but before attempting to solidify the gelatine, and in order to form a thin uniform layer throughout the interior of the tube, the liquefied medium is allowed to run over and moisten completely the inner surface, until every little islet of glass has been