Abstract
LONDON. Royal Society, May 3.—Leonard Hill and A. Eidinow: The influence of temperature on the biological action of light. The biological action of light is accelerated by warmth and retarded by cold. This is true for bacteria, infusoria and human skin. The temperature coefficient for infusoria, between 1° and 20° C., is about 3.0. By adequate exposure to cool air over-action of the sun on the skin can be prevented. The proven success of heliotherapy applied to children with surgical tuberculosis can probably be secured for cases of phthisis if these are no longer exposed in hot sun-boxes, but suitably stripped and exposed in cool air.—F. A. E. Crew: Studies in intersexuality. I.—A peculiar type of developmental intersexuality in the male of the domesticated mammals. Individuals, regarded as females during the earlier part of their lives, later assume the behaviour and the secondary sexual characters of males. They form a series according to the degree of imperfection of the external genitalia and the relative degree of development of the derivatives of the Wolffian and Mullerian ducts. In all there were paired but mal-descended testes. The condition appears to be the result of the absence during the period of differentiation of the sex organisation of that minimum stimulus provided by the sex-differentiating substance, of the sex-hormone, in a zygotic male. The Wolffian and Müllerian ducts pursue an equal and parallel development. The degree of intersexuality varies with the stage during the period of sex-differentiation at which the necessary minimum stimulus was exhibited. Since the assumption of the secondary sexual characters of the male type is normal in time, either the minimum stimulus is ultimately exhibited, or else there is a different threshold of response to the action of the sex-differentiating stimulus on the part of various structures belonging to the sex-equipment.—E. J. Morgan and J. H. Quastel: The reduction of methylene blue by iron compounds. The restoration of the power to reduce methylene blue to boiled milk by means of ferrous sulphate solution is due to the inorganic constituents of the milk. Methylene blue is reduced by ferrous sulphate solution in the presence of sodium hydroxide, carbonate, bicarbonate or phosphate, and of the sodium salts of acids such as acetic, tartaric, or citric. Ferrous sulphate solution alone will not effect any perceptible reduction. Two ferrous molecules always react with one of methylene blue. The mechanism of the reduction appears to depend on the relative affinities of the oxygen acceptor for the hydroxyl ion and of the hydrogen acceptor for the hydrogen ion.—C. F. Cooper: The skull and dentition of Paraceratherium bugtiense. A genus of aberrant rhinoceroses from the Lower Miocene deposits of Dera Bugti. A complete lower jaw, a nearly complete skull, parts of three other skulls, several fragments of lower jaws, numerous loose teeth, and parts of the milk dentition found in Baluchistan are discussed. The lower pair of incisors have the form of tusks turned downward. Even in the oldest specimens they show practically no signs of having been used. The condition of the premolar dentition shows the animal to be in an early state of evolution, but on a side line, with some possible connexion with the early North American Aceratheres. Similar teeth were found in Turkestan by Borrissyak and described by him as belonging to Indricotherium (=Baluchitherium), and a skull has been discovered in Mongolia by the American Museum expedition and attributed to Baluchitherium. It has the enormous length of 5 ft., as against a skull length of 3 ft. in the present form, which makes it the more probable that the two genera are properly separated.—W. L. Balls: The determiners of cellulose structure as seen in the cell walls of cotton hairs. The use of plane and circularly polarised light and of immature hairs shows that the reversals of the spiral fibrillar structure appear in full number, as soon as the secondary wall is visible, indicating predetermination thereof during growth in length. On development of the pre-cellulose, the primary wall shows a pair of opposed spirals with pitches corresponding to that of the slip spirals of the secondary wall. These slip spirals are structurally connected with the quicker pit spirals and invariably opposed to the latter in direction; the tangents of their angles are in the ratio of 4:1, which suggests polymerisation from the pre-cellulose of the primary wall. The rotation of the plane of polarisation by a single layer of secondary cell-wall is inverted on opposite sides of a reversal point; thus the molecular structures of the right-hand and left-hand areas would seem to be mirror-images. The probable space-lattice conformation of cotton and other celluloses seems to indicate a modernised restatement of Nägeli's micellar theory.—I. de B. Daly: The influence of mechanical conditions of the circulation on the electro-cardiogram. Exercise in man produces changes in the electro-cardiogram which are similar to those obtained in anæthetised animals by simultaneous stimulation of both stellate ganglia. Partial or complete denervation of the heart was produced in a dog. Alterations in the mechanical conditions of the circulation were brought about (i.) by partial compression of the systemic aorta at various levels in the body, and (ii.) by changing the conditions of the artificial circulation of the heart-lung preparation. The most marked changes in the electro-cardiogram occurred when the arch of the aorta was partially clamped. The form of the electro-cardiogram of the denervated mammalian heart probably remains unaltered when the increase in work of the heart is produced in a physiological manner.
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Societies and Academies. Nature 111, 653–656 (1923). https://doi.org/10.1038/111653a0
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DOI: https://doi.org/10.1038/111653a0