Societies and Academies

Abstract

LONDON. Royal Society, April 21.—Prof. C. S. Sherrington, president, in the chair.—Prof. J. Joly: A quantum theory of colour vision. In accordance with the physiological law of nerve impulses, known as the “all-or-none” law, the cone is connected with the optic nerve through a plurality of nerve-fibres, the rod being connected through one fibre only. This is supported by histological evidence. The fundamental colour-sensations may be taken as corresponding to frequencies in the ratio 2:3:4, and this is the ratio of the energies of the corresponding quanta and of the kinetic energies of the electrons liberated. It is supposed that this is also the ratio of the numbers of fibres activated in the cone. In the case of the rod, quanta can activate but one fibre; hence its achromatic functions. In the case of the cone the activation of two, three, or four fibres evokes the fundamental sensations. White sensation arises when all nine fibres are activated. Colour-sensation curves, colour blindness, and the energy relations of colour sensation and luminous sensation are discussed.—Prof. A. V. Hill; The energy involved in the electric change in muscle and nerve. An expression is given for the heating effect in a muscle or nerve of the currents produced by the electric response accompanying the propagated impulse. In a muscle the heat produced is not more than one-hundre thousandth part of the energy liberated in a twitch; in a nerve it is of the order of size of 3-5x10-4 calorie. It is concluded from the smallness of these quantities that no appreciable provision of energy is required in the propagation of the electric response, and that the physico-chemical change producing the response is the only factor involved in the propagated nervous impulse.—H. M. Kyle: Asymmetry, metamorphosis, and origin of flat-fishes. The flat-fishes owe their change of form in the beginning to an inherent asymmetry of the abdominal organs, the coil of the gut other organs develop asymmetrically according to the balance, and persistent flexures convey the asymmetry to the skull. Many normal teleosts form a coil and display the same initial disturbances, but their balance is less defective and the skull escapes deformity in various ways. The metamorphosis of flat-fishes takes place during the pelagic stages; the fish swims and lies on one side because that side becomes the heavier. After the demersal habitat has been attained, changes in fundamental structure are improbable, so essential differences indicate separate origins. The flat-fishes have appeared in phylogeny-that is, the skull became affected by the asymmetry of the body when the coil of the gut was farming and -when the caudal region came to occupy more than half the total length. Confirmation of this view is found in the affinity of each group to separate types of normal teleosts ranging from the Macrurids to the Percoids.—T. L. Prankerd: Studies in the cytology of the statolith apparatus in plants, viewed in relation to their habit and biological requirements, (i) The reaction to external stimuli of some liverworts. The degree of geotropic irritability corresponds in general with the biological requirements of the plant. The statolith apparatus is usually absent in vegetative thalli where position is of no-importance, while it is most strikingly developed in the strongly geotropic gametophores and sporogonia, (2) The movements executed by fern-fronds in response to internal and external stimuli. In fifteen-species representative of the FTlicafes geotropic irritability was always present, though both latent and reaction times are greater than the corresponding periods for Anglbsperms, implying physiological evolution. A cylinder of statocyte tissue is always developed in the ground tissue of the young rachis, which disappears at about the time of unfolding of the leaflets, when response to gravity also ceases. In Asplenium bulbiferuin a curve showing the amount of statocyte tissue present corresponds more closely with the curve of geotropism. Growth continues some time after the simultaneous loss of the statolith apparatus and the power of gravitational response.