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Societies and Academies

    Naturevolume 36page408 (1887) | Download Citation



    PARIS. Academy of Sciences, August 16.—M. Janssen in the chair. —Note on the work recently carried out at the Observatory of Meudon, by M. J. Janssen. Special reference is made to the many successful solar photographs already obtained, representing the history of the solar disk for the last ten years. The processes are now so perfected that on the same plate the details are taken both of the brighter and less luminous parts, such as the edge of the disk and the penumbræ of the spots. Photographs ten times enlarged were exhibited of the extremely interesting spots taken on June 22, 1885, and last June. The striæ of the penumbra and the faculæ surrounding the former consist of granulations, in form and size resembling those constituting the entire solar surface. The same phenomenon reappears on the large round spot photographed last July, so that it seems all but demonstrated that the whole solar disk has a uniform constitution, and that the so-called granulations are in fact the constituent elements of every part of the surface of the sun.—Fresh researches on the relations existing between the chemical and mechanical work of the muscular tissue (continued), by M. A. Chauveau, with the co-operation of M. Kaufmann. Here a determination is made of the coefficient of the quantity of mechanical work produced by the muscles performing useful work in the physiological conditions of the normal state. By translating into absolute measurements the indications furnished by the dynamograph already referred to, it is shown that the muscular work performed may be estimated at about 31 to 35 millionths of calorie.—Some further remarks on the radicular nature of the stolons in Nephrolepis, by M. A. Trécul. In reply to M. Lachmann's recent note, the author again shows that these stolons are not stems or stalks, but true roots. No matter what their length, they never produce leaves, have always the structure of roots, and as they alone represent the primary roots of Nephrolepis, the expression “radicular stolons,” applied to them by the author, is fully justified.—New fluorescences with well-defined spectral rays (continued), by M. Lecoq de Boisbaudran. The author here treats fully the combination of alumina and the earth Zβ2O3, which, without being pure, is very rich in Zβ and poor in Zα. Alumina with 1/50 of this earth heated with sulphuric acid and moderately calcined shows a somewhat yellowish-green fluorescence, much more vivid than that of alumina containing the same quantity of Zα2O3 impure. The fluorescences have also been examined of calcined alumina containing the oxides of Ce, La, Er, Tu, Dy, Yb, Gd, Yt, and U. During these researches several rays were noticed apparently belonging to none of the already determined elementary bodies. Some of these rays may perhaps correspond to the substances announced by Mr. Crookes; but each case will have to be determined for itself.—Determination of the longitude of the Observatory of Tacubaya, Mexico, by MM. Anguiano and Pritchett. Continuous observations spread over six months show a definite longitude of 6h. 36m. 46.56s. west of Greenwich, which will require a correction of close upon 5s. for the accepted longitude of the capital of Mexico.—Electric excitement of the liver, by MM. Gréhant and Mislawsky. The question is discussed, whether the excitement of the liver by electricity increases the quantity of urea contained in the blood. In opposition to the views of M. Stolnikow the experiments here described show that variations in quantity occur only in the arterial blood, and that the blood of the supra-hepatic veins presents no change in the weight of the urea after electric excitement of the liver.—Dissemination of the Bacillus of tuberculosis by flies, by MM. Spilmann and Haushalter. Observations recently made in consumptive-hospitals seem to show that the virus (Koch's Bacillus) may easily be disseminated by the house-fly.—Note on Hæmatocytes. by M. Fokker. The author recently showed that the protoplasm taken from a healthy animal and protected from microbes survives and may produce fermentations. Here he continues his researches, showing that this protoplasm is capable of generating a vegetable form different from that under which it existed in the animal organism. But the Hæmatocytes thus produced do not multiply themselves in a cultivating medium, and their development should perhaps be described as a case of heterogeny.

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