Societies and Academies

Abstract

LONDON. Royal Society, April 2.—H. E. Armstrong: Studies on enzyme action, xxiii. The oxidase effect and the phenomena of oxidation in general: carbonic oxide. —N. K. Adam and G. Jessop: An explanation of the so-called “intertraction phenomenon” between solutions and the molecular significance of negative surface tension. Solutions mix by sending out streamers into each other only (i) if they are superposed, and (2) if there is a difference in rate of diffusion between the dissolved substances. The streamers are due to the different rates of diffusion between the two liquids disturbing the hydrostatic equilibrium of the layers. Capillary forces are not concerned. The movements are entirely different if (i) the faster, (2) the slower, diffusing solution is superposed. With these restrictions the phenomenon seems to be general, but it involves no unknown forces. "Negative inter-facial tension "means that the inward attractive forces which, when surface tension is positive, prevent molecules from escaping across the surface of the liquid, become negative. It is properly manifested in diffusion away from the body of the liquid.-Jane Sands: Investigation of oxidation in the blood of earthworms.-R. Snow: Conduction of excitation in the leaf of Mimosa spegazzinii. Simultaneous determinations were made of the velocities of the water current and of the excitatory conduction set up by cuts in the leaves. The latter is many times the more rapid. After the stimulus of a burn, conduction is much more rapid again. Excitation is conducted much more rapidly in the leaves of shoots totally submerged under water for several hours than in leaves attached to the plants in air. In very damp air the velocity of conduction in the leaf is increased to a less extent. Excitation is conducted down the leaf pinnse with great acceleration, and this depends in part on the nature of the process of conduction itself. In the leaf of M. spegazzinii, excitation is regularly conducted by some mechanism that has nothing to do with the water current. Changes of pressure in the tube-cells play no part in conducting excitation, even in the leaf.-Dorothy Adams: Investigations on the crystalline lens. The lens resembles other tissues in possessing an autoxidation system made of two sulphur-containing components: (a) water - soluble glutathione; (6) a thermostable protein residue. Experiments were made on fresh ox lenses, and oxygen uptake was measured directly and indirectly. Fresh lens has a definite oxygen uptake, evidently used for maintenance of its autoxidation system, since any alteration in concentration of glutathione in the lens causes corresponding change in oxygen uptake. The average glutathione content is higher than that of other more vascular tissues. The thermostable protein residue has no oxygen uptake; but with a few milligrams of glutathione it gives an oxygen-uptake curve exactly similar to that of fresh lens. Exposure of fresh ox lens to ultraviolet light or to heat rays causes measurable decrease in its glutathione content. Royal Microscopical Society, February 18.—W. Bernard Crow: Variation in the hormogones of Lyngbya nigra Ag. The hormogones of the blue-green alga, Lyngbya nigra Ag., arise by division from the parent filament, the separation being effected by separation discs. Secondary separation occurs in the free hormogones, leading to the formation of very short hormogones. Some of the latter consist of a single segment only, but do not show the characters of spores. The separation discs, which are special deposits in the protoplasm, sometimes occupy a single segment. Ordinary transverse walls are occasionally absent at certain points in the trichome. Conjugations of adjacent segments in other Cyano-phycese are interpreted as special cases of failure of transverse wall development.-W. L. Roche: Notes on the microscopic anatomy of the tentacular sense organ of Cardium edulis. The siphonal tentacles of the common cockle are sensory structures, and some bear eyes and curious sense organs situated at the bases of ectodermal depressions. These "hair sense organs "occur on ocular tentacles, but may be on eyeless ones; in the former case the same nerve supplies both. These cells are club-shaped, but do not possess stiff hairs which project to the exterior. They give off fibrils which enclose the bases of the cells of the pit which themselves bear sensory hairs. This organ is probably connected with chemical sense.