Page:Popular Science Monthly Volume 47.djvu/728

712 they could not cope with these enemies. Sea snakes are common on some of the islands, of three species, two of which are harmless, while the bite of the other is poisonous. These sea snakes are highly prized, as vipers are in Japan, and are used as food by the rich and, to a smaller extent, as medicine by the poor.

Smoke.—The following, from the American Engineer and Railroad Journal, seems worthy of mention: A mistaken idea exists as to the amount of actual carbon contained in those dense masses of smoke which are seen rising from the tall stacks of manufacturing and other large plants. By passing through water the gases arising from a furnace burning bituminous coal, and weighing the solid particles retained or precipitated, it has been proved, it is claimed, that they amount to less than one sixth of one per cent of the total amount of coal consumed. It is not strange that a different idea is entertained of the quantity of actual carbon seemingly going to waste, when the wonderful coloring power of the finely divided particles of carbon is considered. To prove this it is only necessary to try the well-known experiment of smoking a bit of glass with a candle, and then mixing up with a palette knife a portion of the coloring matter thus secured with a drop or two of gum arabic. A very small portion of this mixture will color many quarts of water. The actual carbon contained in the smoke itself is inappreciable, but the unconsumed invisible gases invariably associated with the smoke are considerable in quantity and indicative of a financial loss much larger than is generally known.

Therapeutic Hypnotism.—The unmistakable signs of the failing belief and interest in hypnotism as a curative agent, and its relegation to the field of curious if not pathological psychology, is pointed out in the editorial columns of the last Lancet. The two deciding questions, about which controversy has raged, have been, first, Are hypnotic phenomena physiological or pathological? and, secondly, Has the induction of hypnosis any therapeutic value? A study of the most successful hypnotic subjects seems to indicate that the phenomenon is really a morbid one, and "associated with feebleness of will and unusual impressionability," and as regards its therapeutics, while it may be of some value in certain functional nervous diseases, such as hysteria and neurasthenia, there are other methods of producing the same effect which have none of the dangers, both moral and physical, with which hypnosis is fraught.

Diphtheria and Milk.—A curious epidemic of diphtheria following a sore throat, caused by drinking a certain milk, is recorded in the British Medical Journal. On the outbreak of the sore throat the milk and its surroundings were closely examined: some of the cows had sore teats; but no disease in the throats of either cows or milkers could be discovered, and there were no Loeffler bacilli in the throat scrapings from the patients. Upon boiling the milk before using, the epidemic promptly subsided. But within less than a week a true epidemic of diphtheria appeared among these same people, and, although careful investigation was made, no source of secondary infection could be discovered. It seems probable that the throat trouble caused by the milk laid the foundation for the diphtheritic bacillus. The outbreak was a very mild one, only one death occurring.

Physical Measurements of School Children.—In J. Allen Gilbert's researches on the mental and physical development of school children, the results in the observations of muscle sense, or sensitiveness to weight, showed a gradual increase in ability to discriminate, from six to thirteen years of age. At thirteen there was a gradual falling off and then another gain. Boys and girls, considered together, gradually increase in ability, but when they are considered separately, marked differences of sex appear. At six years the considerable difference is in favor of the boys; at seven both sexes have the same ability. From this on both gain with equal pace to the age of thirteen, with the exception of an abrupt falling off for boys at eleven. From thirteen to seventeen the difference again becomes manifest in favor of boys. Ability to distinguish different shades of the same color increases with age. The balance of advantage in this test is slightly