Practical bacteriology for chemical students / by David Ellis.

  • David Ellis
Date:
1923
Catalogue details

Licence: In copyright

Credit: Practical bacteriology for chemical students / by David Ellis. Source: Wellcome Collection.

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    cells. The quantity of each must be-so arranged that when a drop is examined under the microscope there will not be more than a dozen Yeast cells present altogether in the field. 2. Place on the marked overslip (See Exercise 96) a loop- ful of this mixture and spread it over the surface of the coverslip so as to make the film as thin as possible. 3. Allow the film to set and then place it film downwards on the moist chamber (Fig. 41). Before putting down the coverslip place a drop of water in the chamber and after puling it down, ring the edge of the coverslip with some substance that will prevent the film from losing much water. Fig. 41.-—Coverslip resting on shallow circular hole scooped out of substance of glass slide. When the coverslip rests on this hole, the latter is completely enclosed. As a drop of water is usually placed in the hole before the coverslip is laid on top of it an air tight moist chamber is formed if the edge of the coverslip, previous to insertion has been greased with some substance like vaseline. 4. Examine under the microscope. In the notebook make a drawing of the coverslip with its squares and figures, and indicate in this drawing where each Yeast cell is placed. See Fig. 40. 5. Incubate at 20 0 C. Examine each day. The chart will indicate the square in which each cell is placed. “Visit” each cell in turn and note the progress, if any, which has taken place in its growth. Note. In place of the hollowed-out slide, an ordinary slide may be used, and a small glass ring attached to it by Fig. 42.— For explanation see text.