Abstract
American Journal of Science, July.—The origin and significance of spines; a study in evolution, by C. E. Beecher. The importance of spines lies not in what they are, but in what they represent. They are simply prickles, thorns, spines or horns. They represent a stage of evolution, a degree of differentiation in the organism, a ratio of its adaptability to its environment, a result of selective forces, and a measure of vital power. Tracing the various groups of forms through their geological development, it is noticed that each group began its history in small, smooth, or unornamented species. As these developed, the spinose forms became more abundant until after the culmination of the group is reached, when this type either became extinct or was continued in smaller or less specialised forms.—Electrical discharge from the point of view of the kinetic theory of matter, by J. E. Moore. When gaseous matter moves in a stream in any definite direction, the pressure of the gas in that direction is increased by an amount proportional to the square of the velocity of translation The author proves experimentally that the pressure in the direction of discharge is greater than in either of the directions at right angles, by an amount depending upon the velocity of the discharge stream.—Further separations of aluminium by hydrochloric acid, by F. S. Havens. Describes the separation of aluminium from zinc by the action of hydrochloric acid gas in aqueous ethereal solution. Also the separation of the same metal from copper, mercury and bismuth.—On the origin of the corundum associated with the peridotites in North Carolina, by J. H. Pratt. The corundum was held in solution by the molten mass of the dunite when it was introduced into the rock, and separated out among the first minerals when the mass began to cool.—The winter condition of the reserve food substances in the stems of certain deciduous trees, by E. M. Wilcox. Material of the Liriodendron collected in October was found to have an abundance of starch in the cells of the cortex, but none in the cells of the medullary sheath, and but few grains in the cells of the wood parenchyma and medullary rays. The cells immediately below the growing point of the stem contained no starch at this time. November and December showed a gradual increase in the amount of the starch in the medullary sheath, but a marked decrease in the amount present in the cortex. At the end of February starch began to appear again in the cortex, but more especially in the cells beneath the growing point.
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Scientific Serials. Nature 58, 335 (1898). https://doi.org/10.1038/058335a0
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DOI: https://doi.org/10.1038/058335a0