Abstract
LONDON. Royal Society, June 18.—Sir William Crookes, president, in the chair.—Sir D. Bruce, Major A. E. Hamerton, Captain D. P. Watson, and Lady Bruce: (1) Trypanosome diseases of domestic animals in Nyasaland. Trypanosoma caprae, Kleine. Part III. —Development in Glossina morsitans; (2) trypanosomes found in wild G. morsitans and wild game in the “fly-belt” of the Upper Shiré Valley; (3) the food of G. morsitans; (4) infectivity of G. morsitans in Nyasaland during 1912 and 1913.—Dr. C. W. Andrews: A description of the skull and skeleton of a peculiarly modified rupicaprine antelope, Myotragus balearicus, Bate. M. balearicus, Bate, is a peculiarly modified rupicaprine antelope, remains of which were discovered by Miss D. M. A. Bate in cavern deposits in Majorca and Minorca. The dentition is very remarkable. Instead of having three incisors and a canine on each side of the mandibular symphysis, as is usual in the Bovidæ, the canines and the two outer pairs of incisors are wanting, while the median incisors are enormously enlarged rodent-like teeth, growing from persistent pulps. The premolars are reduced in number and the molars have very high crowns. The feet are remarkable for the shortness and stoutness of the metacarpals and metatarsals, which are quite similar to those of the Takin (Budorcas). The animal seems to have been adapted for climbing on steep crags and cliffs, and probably lived on very hard vegetation.—E. T. Hainan and F. H. A. Marshall: The relation between the thymus and the generative organs, and the influence of these organs upon growth. With a note by G. U. Yule. —H. E. Roaf: The vapour pressure hypothesis of contraction of striated muscle. Two objections have been urged against muscular contraction being due to movements of water from one portion of the muscle fibre to another. These are: (1) that an osmotic model of muscle cannot cause a sufficient degree of shortening; and (2) that the movement of water would require a longer time than the muscle takes in contracting. The extent of contraction possible for an osmotic model and the time required for this contraction has been calculated for structures of the dimensions of frog's sartorius. It is found that the extent of contraction can be explained by the osmotic model, and that the time required is less than 0.03 sec., and frog's sartorius requires at least 0.04 sec. for complete contraction.—A. N. Drury: The validity of the microchemical test for the oxygen place in tissues. Experiments were made to show that the microchemical test with rongalit white, used by Unna to fix the position of the oxygen place in tissues, could be obtained on a surface entirely free from oxygen. A further extension of the work showed that the condensation of a solute on to a surface is markedly influenced by the previous treatment of, or by the gas condensed on, that surface.—Prof. J. S. MacDonald: Man's mechanical efficiency. The rate of heat-production, Q, associated with cycling at a uniform rate but with varied performances of mechanical work, is expressed in the following form, x + Ey = Q, where x represents the heat-production associated with the uniform rate of movement, y the rate of work-performance. It is shown that E varies inversely with W2/3. It follows that, putting on one side x, the energy-transformation entailed by the movements per se, the additional energy-transformation required for any definite rate of work-performance is less the greater the weight, W, of the worker; and the mechanical efficiency measured in this fashion varies directlv with W2/3. It is also shown, however, that x varies approximately with W3/2, and thus that the energy-transformation associated with the mere production of movement is much greater the greater the weight. —Dr. A. Holt: The colouring matters in the compound Ascidian, Diazona violacea, Savigny.—Prof. W. B. Bottomley: Some accessory factors in plant growth and nutrition. Plant growth-stimulating substances are formed in sphagnum peak when it is incubated with a liquid culture of certain aerobic soil bacteria for a fortnight at 24° C. These substances are soluble in water and in alcohol, and are active in very small amounts, two applications of water-extract of 0.18 gram treated peat doubling the size of Primula malacoides seedlings over untreated plants in six weeks' time. They appear to be similar to so-called accessory food substances essential for nutrition of growing animals, first studied in connection with the deficiency diseases beri-beri and scurvy. The production of these substances appears to be associated with formation of soluble humates in peat by bacterial action. They are not formed when peat is treated with alkalies. Cultures of Azotobacter chroococcum grown with extract of “bacterised” peat gave an increase of 18 milligrams of nitrogen in eight days, whilst extract of chemically-treated peat gave no increased fixation. The active substance is precipitated from aqueous solution of alcoholic extract of “bacterised” peat by phosphotungstic acid, and can be further separated by decomposing with baryta, reprecipitating with silver nitrate and decomposing with hydrogen sulphide. Wheat seedlings in sand culture with Detmer's complete food solution gave an increase of 22.7 per cent, with the phosphotungstic fraction, and 17.7 per cent, with the silver fraction. Water-culture experiments with wheat seedlings in Detmer's solution prepared from pure salts in physiologically pure distilled water showed that these substances are essential for assimilation of inorganic food constituents.—Prof. H. B. Dixon, C. Campbell, and W. E. Slater: A photographic analysis of explosion-flames traversing a magnetic field. The authors have carried out a suggestion made by Sir J. J. Thomson that the explosion-wave in gases should be photographed on a rapidly moving film while it traverses a strong magnetic field, to determine whether the emission of electrons in front of the wave “prepares the way” by ionising the gases. Using a very powerful magnet lent them by Sir E. Rutherford,the authors have photographically analysed the explosion-wave in different mixtures of gases before it enters, while traversing, and as it leaves, the magnetic field. In no case did the magnetic field alter the character or velocity of the flames.
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Societies and Academies . Nature 93, 445–447 (1914). https://doi.org/10.1038/093445a0
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DOI: https://doi.org/10.1038/093445a0