Page:Popular Science Monthly Volume 24.djvu/299
ing which produce secretions of slime, or by the presence of cells containing crystals of oxalate of lime. The operation of these agencies is associated with the action of secretory organs, or glandular processes, causing a tendency of particular substances to certain points. The cells forming the transparent points probably have some particular significance in connection with the life of the leaf, for their occurrence is so uniform in particular species that they become distinguishing marks by which the species is known. So, also, the presence of raphides-cells (cells containing needle-shaped crystals of oxalate of lime) is constant in some families, as in the Dioscoreas, smilaxes, and Taccaceæ, although the transparent points are rarely observed in their leaves. Cells containing resin or ethereal oil are constant in at least three species of pepper, and in all of the Monimiaceæ. Interior glands, with brown radiating crystals of resinous substance, are characteristic of the Myrsinieæ, and are wanting in only a few species. The anatomical structure which leads to the production of these points evidently has some systematic importance, and should not be overlooked in the determination of the characteristics of the different groups.
In Dr. Pyburn's article on "A Homemade Telescope," in the last (November) number of the "Monthly," page 86, seven lines from the bottom, the diameter of the thirty-inch roller is given as "two and five eighths inches"; it should read "one and five eighths inch."
Professor Baird announces the final solution of the problem of the culture of oysters from artificially impregnated eggs. The Government station at Stockton, Maryland, had in September last many millions of young oysters three quarters of an inch in diameter, which had been hatched from eggs artificially impregnated forty-six days before. Oyster's had already been artificially impregnated by Dr. Brooks, but the practical difficulty existed of preventing the young oysters, which could pass through the meshes of the most closely woven fabrics, from escaping.
Our Educational Bureau is circulating an excellent paper from an address given to school-teachers in Switzerland on how natural science should be taught. The object, it says, should be, not to fill the mind with facts, but to bring all the scholars, including the slowest ones, to discover and observe facts for themselves. Books should be little used, and nothing about an object should be taught without the object being before the class. The next lessons should be in describing the facts observed, with the help of drawing, if possible. Plants should be chosen first, then animals of different classes, then minerals, with observations of mechanical and afterward of chemical effects upon them. But the bare making of collections should not be particularly encouraged.
The "United States Hay Fever Association" held its tenth annual meeting at Bethlehem, New Hampshire, during the last week in August. The speeches made and the experiences related indicate that the cause and specific cure for the uncomfortable disease in question are yet to be found. A particular preparation which has been much recommended was, by nearly general consent, pronounced of no value as a remedy. Much information regarding the malady had been gathered by Dr. Geddings.
The lowering of the freezing-point of water by increased pressure is frequently illustrated by the experiment of Bottomley, which consists in throwing across a cake of ice a wire weighted heavily at both ends. The wire slowly sinks through the cake, the ice melting beneath it and freezing above it. Professor Guthrie, at a meeting of the Physical Society in London, has stated his belief that the wire conducts heat to the ice from the atmosphere, and that therefore the experiment does not illustrate the fact above mentioned. A silk cord weighted to the same amount as a wire will not cut through a block of ice.
The death is recorded of Hermann Müller, of Lippstadt, one of the most industrious and distinguished scientific investigators of the day. His specialty was the fertilization of flowers by insects, in which subject he was regarded by naturalists as the highest authority. He was the author of two books on the subject, "Die Befruchtung der Blumen durch Insecten" ("The Fertilization of Flowers by Insects"), recently translated into English, and "Alpenblumen, ihre Befruchtung durch Insecten" ("Alpine Flowers, their Fertilization by Insects"); of an article in Schenk's "Handbuch der Botanie," and of frequent contributions to the German periodical "Kosmos."Ernest Ingersoll observes, in the "American Naturalist," that if we judge by the standard of their possessing a convenient currency, the American Indians must be ranked high among barbarians in point of advance toward civilization. They had in their wampum a regular money of recognized value. It marked an advance upon