LONDON. Royal Society, February 27.—Sir Archibald Geikie, K.C.B., president, in the chair.—F. Soddy: The i periodic law from the point of view of recent results in radio-activity.—C. F. Jenkin and D. R. Pye: The thermal properties of carbonic acid at low temperatures. The paper describes a series of experiments made in the engineering laboratory at Oxford, undertaken with the object of checking by direct measurements the accuracy of the accepted CO2 entropy-temperature diagram, due to Mollier, and of extending the diagram to lower temperatures, i.e. from —30° C. to —50° C.—E. Roberts: Re-reductions of Dover tidal observations, 1883–4, &c.—Prof. F. Keeble, Dr. E. F. Armstrong, and W. N. Jones: The formation of anthocyan pigments in plants. Part iv., The chromogens. The results of the experiments described in this paper lend support to the hypothesis that the anthocyan pigments of plants are produced by the oxidation of colourless chromogens. Under certain conditions a coloured flower may be caused to reverse its pigment-forming process and to reduce the pigment which it contains to a colourless state. By again changing the conditions the pigment-forming mechanism may be made to resume activity and to give rise to pigments identical in colour with those of the normal intact flower. Whether the flower forms pigment or remains colourless depends on the degree of hydration of its tissues. If water be withdrawn from the tissues oxydase activity falls off, the activity of “reducing-bodies” becomes increased—actually or relatively—pigment formation is inhibited, and the pigment in existence already is reduced to chromogen. The flower becomes colourless. If water be supplied to the decolorised tissues, oxydase resumes its activity and chromogens are oxidised to pigments.—W. N. Jones: The formation of the anthocyan pigments of plants. Part v., The chromogens of white flowers. This paper, which deals with the biochemistry of the pigment-forming mechanism contained in white flowers, is a continuation of the work summarised in part. iv. of the present series of communications. As shown in the latter paper, the pigments of flowers may be reduced to the state of colourless chromogens and may be re-formed by artificial means from those chromogens. In the present paper it is shown that chromogens may be obtained from some white flowers and may be caused by similar treatment to give rise to pigments.—Mabel P. FitzGerald: The changes in the I breathing and the blood at various high altitudes. The observations described in the paper were made during the summer of 1911 on persons residing in towns, mining camps, &c., at various altitudes from 5000 to 14,000 ft. in the Colorado portion of the Rocky Mountains. The main conclusions reached are as follows:—(i) The volume of air breathed per unit mass of CO2 produced by the body is always increased in persons acclimatised at high altitudes. The mean increase of breathing is such as to produce a fall of about 4·2 mm. (or roughly 10 per cent, of the normal for sea-level) in the partial pressure of CO2, in the air normally present in the lung alveoli for every 100 mm. of fall in the barometric pressure. Both men and women show this fall, after allowance is made for the normal difference in the alveolar CO2, pressure of men and women. (2) The percentage of haemoglobin in the blood of acclimatised persons is likewise increased, the mean increase being about 10 per cent, of the normal at sea-level in men for every 100 mm. of diminution in the barometric pressure. Both men and women show this fall. (3) It may take some weeks for these changes to establish themselves fully in persons passing to a high altitude or to disappear in persons passing to sea-level.
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Mar 1, 1925
A C White 
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