Abstract
LONDON. Royal Society, February 25.—Sir William Crookes, president, in the chair.—Prof., L. Hill and J. F. Twort: The effect of the depth of pulmonary ventilation on the oxygen in the venous blood?? man.—J. Barcroft and Toyojiro Kato: The effect of functional activity upon the metabolism, blood flow, and exudation in organs. The organ studies have been skeletal muscle and the submaxillary gland. (1) The oxygen used by these organs not only increases during their activity but outlasts it by some hours. The curve of oxidation usually shows two maxima, the first during the period of activity, the second much later. (2) water leaves the blood-vessels in much greater quantities during and after activity of the organs than before; a similar second maximum is sometimes seen in the case of the exudation. (3) In the case of muscle not all the exudation leaves the muscles as lymph. Of the right and left gastrocnemius muscles, the one which has been stimulated is heavier several hours after the stimulation, and of lower specific gravity than the unstimulated one. (4) The dilatation of the vessels of the organ outlasts the functional activity for two hours or more in the case of muscle which has been stimulated rhythmically for fifteen minutes. (5) The tenseness of the muscle caused by its distension with water would seem to be the physical basis of stiffness.—Miss D. Jordan Lloyd: The osmotic balance of skeletal muscle. In order to free the phenomena as far as possible from complications due to the formation of diffusion columns, a very small flat muscle the sternocutaneous of the frog-was used. The results of experiments show that an oxygen-saturated muscle has an osmotic equivalent less than that of distilled water.—Dr. A. J. Ewart: The function of chlorophyll. Previous observations of the author have tended to support the theory that chlorophyll is a stage in photosynthesis. The present paper develops this idea further. By means of Wellstatter's methods of extraction and separation, chlorophyll, carotin, and xanthophyll were obtained in the pure state and used for the experiments. The following conclusions were reached:—(1) No peroxides, organic or inorganic, are produced during the photo-oxidation of chlorophyll, xanthophyll, and carotin. The oxidising effect of these latter substances on potassium iodide when they are undergoing oxidation in the light is due to the fact that in the presence of abundant oxygen they can act as oxidases, not only to themselves, but also to substances with which they may be in contact, such as hydriodic acid, litmus, or guaiacum. (2) Chlorophyll and xanthophyll decompose during photo-oxidation into (a) solids, and (b) a gas. The solids are colourless, waxy substances and hexose sugars. The gas is formaldehyde gas. With dry films in dry air free from CO2 relatively more formaldehyde is produced and less sugar. (3) Carbon dioxide combines with chlorophyll, forming xanthophyll and a colourless waxy solid. The combination only takes place actively in the presence of water, and is accelerated by sunlight.—A. Compton: The influence of the hydrogen ion concentration upon the optimum temperature of a ferment.—M. Back, K. M. Cogan, and A. E. Towers: Functional oedema in frogs. If the gastrocnemius muscle of a frog be stimulated for fifteen minutes with forty induction shocks per minute it becomes heavier than the other. The difference in weight may amount to upwards of 20 per cent, of the weight of the muscle. The specific gravity falls correspondingly. This phenomenon may be noticed from fifteen minutes after the stimulation ceases to six hours. After sixteen hours the oedema has passed off.
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Societies and Academies . Nature 95, 25–28 (1915). https://doi.org/10.1038/095025a0
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DOI: https://doi.org/10.1038/095025a0