I. On a certain excretion of carbonic acid by living plants

• Published in: Proceedings of the Royal Society of London
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 1869
• Subjects: Freed; Carbonic acid
• Online Access: http://dx.doi.org/10.1098/rspl.1868.0080; https://royalsocietypublishing.org/doi/pdf/10.1098/rspl.1868.0080

While the author was engaged in some experimental determinations of the changes that take place in the composition of the Cinchona barks after being taken from the tree, he noticed a somewhat singular circumstance, which induced him to institute a series of experiments, by which he discovered that the various parts of living plants excrete carbonic acid, not only in their normal condition, but after they have been deprived for days together of all access of oxygen. The experiments were mostly made on cut portions of the plants; but experiments were also made, for control, on plants as they actually grow. The deprivation of oxygen was effected sometimes by Sprengel’s air-pump, sometimes by substituting for air an atmosphere of hydrogen or nitrogen; while comparative experiments were made on plants supplied with air that had been freed from carbonic acid. The main conclusions to which he was led are those enunciated by the author:— 1st. That nearly all parts of growing plants evolve carbonic acid in considerable quantities, quite independently of direct oxidation. 2nd. That this evolution is connected with the life of the plant. 3rd. That it is due to two causes, namely, to previous oxidation, result­ing after a lapse of time in the production of carbonic acid, and to the separation of carbonic acid from the proximate principles of the plant while undergoing the chemical changes incident to plant-growth.