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.

    97/152 (page 85)
    Exercise 69. Growth of bacteria on ghjcerinc-yotaio. This medium is recommended in growing chromogenic bacteria. 1. With a cork-borer cut cylindrical portions out of a healthy potato. These portions should be about 4 ems long and about 1*5 ems in diameter. 2. Halve each cylinder diagonally (see Fig. 36) and cut away any portions of skin that may not have been removed. 3. Make a solution of 1 : 1000 Sodium Carbonate and soak the pieces in this substance for 24 hours (not longer). 4. After 24 hours transfer the pieces to water containing 5 % glycerine and leave! for 24 hours (not longer). 5. Sterilise wide test-tubes, place in each 1 c.c. of sterile water, and a glass rod, 2ems long and about cm in diameter. 6. In each tube insert a piece of potato (see Fig. 36) with the broad end of the wedge in the downward position. It will be seen that by this arrangement the potato will be supplied with moisture without being actually in contact with the water. 7. Plug tubes with cotton-wool and sterilise by placing in steam steriliser (1000 C.) on 4 successive days for 20 minutes each time.