Societies and Academies

    Abstract

    PARIS. Academy of Sciences, April 30.—M. Lœwy in the chair.—On the equilibrium of ocean waters, by M. Poincaré. A mathematical paper dealing with the theory of tides.—On the soil and climate of the island of Madagascar from an agricultural standpoint, by M. Grandidier. The author warns intending colonists of the comparative infertility of most of the soils in Madagascar, notwithstanding the apparently vigorous vegetable growth supported thereon, and points out the importance of meteorological conditions, which are peculiarly unfavourable in certain districts.—Digestion without digestive ferments, by M. A. Dastre. Fresh proteids (fibrin, albumin, &c.) undergo the same series of changes when subjected to the prolonged action of 10-15 per cent, solutions of ammonium or sodium chloride (or 1-2 per cent, sodium fluoride), as when acted on by gastric juice.—Observations of Gale's comet made at Nice and at Algiers, by M. Tisserand.—Elliptic elements of Denning's comet, 1894, by M. L. Schulhof.—Observations of the same comet made at Toulouse Observatory, by MM. E. Cosserat and F. Rossard.—A theorem concerning the areas described in the movement of a plane figure, by M. G. Kœnigs. If a finite arc AB of any curvature roll upon any arc of equal length successively on the two sides of this arc, the area swept by the radius IM joining the instantaneous centre to a point? on the arc AB is independent of the form of the arc AB.—On the lines of curvature of surfaces cerclées, by M. Lelieuvre.—On the analytical integrals of equations of the form d"z?? \? \ - = F", F"= k, by M. Delassus.-A note by M. Bendixon on a theorem by M. Poincare.-On hysteresis and permanent deformations, by M. P. Duhem.-On a new method of determining critical temperatures by the critical indix, by M. James Chappuis. The author employs the method of interference fringes for following the variation in the index of refraction of the substance examined. The critical temperature of carbon dioxide determined by this method is 31'40°, a number in substantial agreement wiih Amagat's determination 3l-35°.-On a new method for the determination of the lowering of the freezing point of solutions, by M. A. Ponsot. The temperature is read at which a solution is in equilibrium with a quantity of ice with which it is thoroughly agitated, the exterior radiation being minimised, and the solution is then in part withdrawn and analysed.-On cupric bromide, by M. Paul Sabatier. The anhydrous salt and the form CuLir2, 4H2O are described. The green crystals 01 the latter lose water over sulphuric acid and are converted into black CuBr2.-On an uusaturated natural ketone, by MM. Ph. Barbier and L. Bouveault. This ketone is obtained from crude essence of lemon grass (Andropogon citralns). It has the composition (CH3)2: C: CH. CH2, Cilj, CO, CH3. It has a very agreeable but penetrating odour, and boils at 169-1700 under ordinary pressure.-A purely mechanical action suffices for Cliona to bore its tunnels in the valves of oysters, by M. Letellier.-On the glandular system of ants, by M. Charles Janet.-Creation of new varieties by grafting, by M. Lucien Daniel. Hybridisation by grafting is possible for certain herbaceous plants which can be made to aiquire new alimentary qualities by grafting them on plants superior to them in this respect, and afterwards sowing seed from the graft. The influence on the graft varies, but is particularly marked among the Cruciferae.- On the chemical composition of wavellites and turquoises, by M. Adolphe Carnot.-On the microstructure of mililite, by M. L. Gentil.-New researches on association among bacteria. Augmentation of the virulence of certain microbes. Increase of receptivity: A note by M. V. Galtier in which the following conclusions are given:-(j) Microbes, attenuated till they cannot alone produce a mortal malady, become again virulent when two species are introduced into the organism. (2) The two species may multiply side by side, but generally one tends to disappear, and the other becomes again pathogenous. (3) When two species of microbes are found associated, it is sometimes one and sometimes the other which regains its virulence according to the conditions. (4) Association of bacteria is able to be employed in the laboratory to render attenuated microbes again virulent. (5) Not only can the return of certain epidemics be explained by it, but the effects of vaccination with mild virus may be aggravated by this means. (6) The passage of one microbe, conferring immunity against a given malady, may predispose to the attack of another.-Properties of serum from animals protected against the poisons of different species of serpents, by M. A. Calmette.

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