Page:Popular Science Monthly Volume 39.djvu/291

Rh irritation now exists than formerly, it is necessary to seek another cause for the increase of cancer. "When we investigate the personal history of cancerous persons, it is impossible to avoid being struck by the large number who speak of antecedent trouble, worry, or mental anxiety. In particular, the face of the average woman sufferer—care-worn, thin, and anxious—constitutes a type well known at every general hospital." The reason of the supposed connection can not be explained; "but the immediate sequence is a matter of daily familiarity, insomuch that it may be laid down as an axiom wherever the antecedents of any major cancerous growth are to be investigated, 'Failing a mechanical exciting cause, a neurotic is always to be found'; provided only that sufficient evidence of previous history and surroundings is procurable. Moreover, it is to be noted that the female, the more neurotic and emotional sex, are the principal sufferers from cancer; also that the organs in them by far the most prone to diseases of this class are normally, in health, specially and peculiarly influenced by emotional conditions, and by states of the central nervous system." The author has made some inquiry into possible hereditary transmission of cancer, but failed to find a sufficient proportion of cases of hereditary connection to justify his including that among general controlling causes.

Fine Quartz Fibers.—In a lecture on quartz fibers and their applications, Prof. C. Vernon Boys began by explaining that the physicist in making his experiments has often to deal with very small forces, which are sometimes measured by the direct pull they exert, and sometimes by the twisting effect they can produce when applied at the end of an arm acting as a lever. It is often necessary to be able to detect and measure forces not larger than the weight of a millionth or even of a thousand-millionth of a grain. If these are used to produce a twist in a wire, the wire must be exceedingly thin for the twist to be measurable. A wire when reduced to one tenth of its original thickness will only require one ten-thousandth part of the force to twist it by the same amount; and, consequently, we can measure forces as small as we please if we can only get wires thin enough. Formerly experimenters made use of metal wires, but these were soon replaced by fibers of spun glass, which can be got far finer. Glass, however, has one great drawback, in that it will not, when twisted, return to its original position after removing the twisting force, but acquires a permanent twist, and this renders it very difficult to use in delicate instruments. If we want finer wires we must turn to the single fibers obtained from the cocoons of silk-worms. These are so fine that in ordinary instruments the force required to twist them is so small as to be considered quite negligible. Some three years ago the lecturer constructed an instrument (radiomicrometer) to measure the difference in the amounts of heat radiated from different parts of the disks of the sun and moon. In this instrument it was' necessary to measure a force so excessively small that even a silk fiber was too coarse. He therefore endeavored to obtain finer wires by shooting a very light arrow, which drew after it a very fine fiber of quartz from a piece of molten quartz held in the flame of an oxyhydrogen blowpipe. In this manner a thread of quartz can be obtained which is not more than one fifteen-thousandth of an inch in diameter, and which will show an appreciable twist with a force of a thousand-millionth of a grain weight applied at the end of a lever one inch long. The lecture was illustrated by a number of experiments.

Consumption Germs.—Speaking at the Sanitary Convention in Vicksburg, Miss., of December, 1889, Dr. A. Arnold Clark, of Lansing, Mich., accepted the germ as the chief source of the disease, and referred to experiments in which the germs had been found on the walls of rooms where consumptives had been; they are derived from the dried sputa of the patients. Animals, according to Dr. Cagny, feeding on the sputa die of consumption; and the disease has been produced by inoculating with the sputa, by swallowing it, and by breathing it. "When we think of the ten thousand consumptives in Michigan who every hour in the day are expectorating along our streets, and even on the floors of public buildings, post-offices, churches, hotels, railroad cars, and street cars; when we think how these