A course of practical instruction in elementary biology / by T. H. Huxley, assisted by H. N. Martin.

  • Martin H. Newell (Henry Newell), 1848-1896.
Date:
1875
Catalogue details

Licence: Public Domain Mark

Credit: A course of practical instruction in elementary biology / by T. H. Huxley, assisted by H. N. Martin. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    ■ [B. Physiology. Get some water that is quite green from containing a large quantity of Protococcus; introduce some of it . into two tubes inverted over mercury, and pass a small quantity of carbonic anhydride into each : keep one tube in the dark and place the other in bright sunlight for some hours. Then measure the gas in each tube and after- wards introduce a fragment of caustic potash into each; the gas from the specimen kept in the dark will be more or less completely absorbed ( = carbonic anhydride), that from the other will not be absorbed by the potash alone, but will be absorbed on the further introduction of a few drops of solution of pyrogallic acid (= oxygen). Protococcus, there- fore, in the sunlight, takes up carbonic anhydride and evolves oxygen. A comparative experiment may be made with a third tube containing water but no Protococcus.]