Chemical phenomena in life / [Friedrich Czapek].

  • Czapek, Friedrich, 1868-1921.
Date:
1911
Catalogue details

Licence: Public Domain Mark

Credit: Chemical phenomena in life / [Friedrich Czapek]. Source: Wellcome Collection.

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    result that the velocity of reaction is doubled or trebled when the temperature increases by io degrees. This rule, well known to the chemists of our days as Van ’t Hoff's Rule or the R.G.T.- Rule, is in practice applicable between the ex¬ tremes of - 50 and 300 degrees. Below and above these extremes the quotient is larger than 3 or smaller than 2. It is of great interest to see that chemical reactions in plants strictly follow the same rule. F. F. Blackman and Miss Matthsei showed that the dependence of the carbon- assimilation of leaves in sunlight upon the tem¬ perature is an exact example of Van ’t Hoff’s Rule. Blackman stated the same for the respiration of plants. Kanitz drew attention to many former observations of different authors which demon¬ strate quite sufficiently that the R.G.T.-Rule is avail¬ able for protoplasma-streaming, geotropism, longi¬ tudinal growth, pulsation of vacuoles in cells, etc. As well as the influence of temperature on chemical reactions, the influence of the physical condition of the reacting substances is an old laboratory experience : Corpora non agunt nisi fluida. The chemist is accustomed to dissolve the substance which is to be used in an experiment to react on other substances. The chemical course in living cells is the same. All substances destined for reactions are first dissolved. No compound is taken up into living cells before it has been dis¬ solved. So the mineral salts of soil, the organic