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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    APPENDIX. Note 1. When pouring the contents of a test-tube into a Petri-dish, it is important that the operation should be performed in such a way that the liquid is exposed to the atmosphere for as short a time as possible. The diagram in Fig. 53 shows how this may be accomplished. As soon as the stopper is removed from the test-tube, the lid of the Petri-dish is raised as shown in the diagram, the test-tube inserted under the raised lid, the liquid poured into the dish„ and the Petri-dish cover closed immediately. F’g- 53- Fig. 54- Note 2. In transferring material from one test-tube to another, it is not advisable to lay the stoppers on the sur- face of the table, for fear of contamination. When the tube- end of the stopper is only in contact with the air the risk of contamination is much less than if it lay on the table. In Fig. 54 is shown one way of holding two test-tubes with the left hand, and at the same time allowing the fingers freedom to hold the two cotton-wool stoppers which have