Page:Popular Science Monthly Volume 35.djvu/446

426 of an epileptic seizure taking place suddenly in an apparently healthy person is one of such every-day occurrence that it scarcely excites any notice. But if a medical witness stands up in court and suggests that an atrocious and apparently motiveless act of violence was the insane act of the apparently calm prisoner in the dock, he is in danger of being ridiculed as a theorist."

A Practical View of Parks.—Lord Brabazon, at the Sanitary Congress held in York in September, 1886, defended the propriety of maintaining parks in large towns upon the broadest practical grounds. Such establishments, he held, should not be considered luxuries, but public necessities. For health is one of the first of necessities, and no expense should be spared, and no opportunity neglected, to increase the average standard of the nation's health and strength. If a people's average standard of vitality be lowered, that people will assuredly be handicapped in the race of nations by as much as that standard has been lessened. The health of the mind is largely dependent on the health of the body, and a nation can only as have much muscular power and brain force as may be the sum total of those qualities possessed by the men and women of which it is formed. It is an axiom of hygienic science that, other things being equal, the health of a population is in inverse ratio to its density. Hence the density of population in large towns should be offset by providing as much open space as possible in the form of squares, parks, and pleasure-grounds.

Dangers of the Laboratory.—A striking instance of the dangerous quests which enthusiastic chemists undertake are the efforts to investigate the yellow oily substance called chloride of nitrogen. This terrible explosive was discovered in 1811 by Dulong, who lost one eye and three fingers in a vain attempt to ascertain its composition. So powerful is it that when Faraday and Sir Humphry Davy took it in hand they provided themselves with thick glass masks to protect their eyes from flying bits of glass, and to some extent from the irritating vapors of the oil itself. Faraday was on one occasion stunned by a detonation of only a few grains of the compound, and bits of the tube in which it had been contained almost penetrated his mask. On another occasion Sir H. Davy was severely injured by the explosion of a few drops under the receiver of an air-pump. Since their time the precise composition of the oil has been a mystery. At last, however, Dr. Gattermann, of Göttingen, has succeeded in its analysis. He finds that the substance examined hitherto was impure, and that the extreme danger of handling it was partly due to that fact, and partly to the varying action of light. Any bright light, he has found, is enough to produce detonation—a discovery made by the sudden destruction of his apparatus by a stray sunbeam. Chemical research nowadays is apt to stray among the teeming pastures of organic chemistry, to the neglect of the old problems offered by the inorganic world, though the solution of these problems should enlist the highest efforts of experimental science.

Superstitions about Snakes.—Besides certain errors in natural history, imagination has vested snakes with some supernatural or uncanny qualities. Thus, they are in some places believed to know where buried treasures are deposited; to lie upon the gold in winter; and, while too wary to show themselves near their hoard in summer, to come out in the bright, warm days of spring and bask in the neighborhood of their winter quarters. At such times a wise man will not kill them, but will watch where they go, mark the place, and take measures to possess himself of the treasure. But the snake is supposed to fight wildly for his property; and there are feigned to be in the old mines of Italy winged serpents which never come into the open air, but haunt the vaults where anything of value is hidden. They live upon the scent of gold, and violently attack any one who forces his way into their domain. No one, it is added, has ever seen them except by torch-light, when they must have looked rather like bats. The house-snake in Carinthia is supposed to bring good luck to the house he frequents. The fatter he grows the fuller will be the stalls, the granaries and the kitchen. So he is not disturbed, but has a bowl of milk placed every morning and evening in the cellar where he lives. Some of these serpents are fabled