Practical bacteriology for chemical students / by David Ellis.

  • Ellis, David, 1874-1937.
Date:
1923
Catalogue details

Licence: In copyright

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

    18/152 (page 6)
    Choice of temperature for cultivation of organisms. All micro-organisms do not begin to grow or cease to grow, or grow at their best at the same temperatures. Care should be taken to select an Incubator with a range of temperature which includes the optimum temperature of growth of the class of organisms which it is intended to cultivate. (e) Jar for holding Sterile Water. A very efficient apparatus is that shown in Fig. 6. The all important object is to prevent the water which, has been sterilised from receiving subsequent contamination from the micro-organisms of the atmosphere. (f) Wire Cages. Different forms are shown in Fig. 7. (g) Specicd Apparatus for Sterilisation and subsequent protection of Petri-dishes. (Fig. 8.) (h) Apparatus that should be in the possession of each student. 1. Half d dozen Petri-dishes. (Fig. 9 a.) 2. Platinum needle and Platinum loop. The Platinum should not be less than 0.015 inch in thickness and should be from 2 to 3 inches long. (Fig. 9 b.) 3. Smith and Durham Fermentation Tubes. (Fig. 9 c.) 4. Two or three dozen Test.-tubes. 5. A few Erlenmeyer Flasks (500 c.c. and 250 c.c. Fig. 9d.) 6. Graduated Pipettes. 7. A few Beakers (500 c.c. and 250 c.c.). 8. Two or three Hansen-flasks. (Fig. 9e.) 9. Glass Slides and Coverslips. The coverslip must not be so thick that a high-powered lens e. g. a im- mersion lens cannot be brought into focus with the ob- ject that it covers. On the other hand if they are very thin the number of casualties during the process of cleaning may be very great. 10. Eeceptacles for Glass Slides and Coverslips. When not in use these articles after being cleaned should be kept in alcohol and taken out only when about to be used. Small glass vessels with ground glass stoppers