Page:Popular Science Monthly Volume 33.djvu/299

Rh deleterious effect of arsenic upon the skin was recently discussed in the Pathological Society of London, after a communication by Mr. Jonathan Hutchinson. The skin is the tissue on which arsenic has perhaps its most marked influence. The poison may spoil the complexion instead of improving it, by making it muddy and unsightly. A similar action is exhibited in all parts of the skin, and may lead to the development of soft corns, not warts, in the palms of the hand and soles of the feet, where a roughened condition also grows up under its influence. Mr. Hutchinson expressed the belief that arsenic can produce epithelial cancer.

that the coincidence of the earth's perihelion passage with the summer solstice every twenty-one thousand years marks the regular recurrence of a northern glacial period, M. Adolphe d'Assier has calculated that the last glacial period reached its culmination in 9250 and that the alternating period of greatest warmth in the northern hemisphere occurred  1250, after which we immediately began to move toward the next glacial period, which will reach its height in, say,  11,750. Hence the north must have been growing cooler during the last six hundred years. Evidence is not wanting, M. d'Assier asserts, in changes that have been observed in the northern limits of growth and ripening of certain plants, that this has been the case, and he names several instances.

in a paper on Dr. Thomas H. Street's collection of birds' sterna and skulls, mentions as a fact long well known to him, which is illustrated by specimens in the collection, that there are a great many species of North American birds that gradually increase in size as we pass from the southern parts of the country toward the north.

Congo in the neighborhood of Stanley Falls, according to the account of an English engineer formerly in the service of the Free State, is so full of islands that an uninterrupted view from bank to bank is obtained at only three or four points. The misleading statement, without mention of the islands, that both shores are seldom visible at the same time, has given rise to mistaken and exaggerated ideas of the size of the river. The great plain, some five hundred miles in extent, through which it runs here, is covered for the most part with dense tropical jungle, abounding in rare and valuable forms of plant-life. Tree ferns, and many varieties of orchids yet undescribed, are common, as well as the wild coffee shrub, several kinds of plants yielding India-rubber, mahogany, and other splendid timber-trees.

combat between two hawks and an owl is described in Major-General Newhall's "Highlands of India." The three birds first performed a preliminary series of upward gyrations, each endeavoring to get a position of advantage above the other. Finally one of the hawks made good his stroke, and both birds fell to the ground like a stone. When the author rode up, the little hawk was standing in the attitude of a conqueror on the owl's body, whose head he had twisted off and held in his claw.

world consumes annually, according to an English authority in the trade, about 650,000 tons of coffee, and produces a corresponding quantity. Estimating the average price at $400 a ton, this represents a value of $260,000,000. Jamaica coffee is the finest grown, but only furnishes about 5,000 tons. East Indian and Ceylon coffees are of very high quality, but they do not together produce more than 25,000 tons. The Ceylon crop used to be more important than it is, but has been reduced in consequence of a disease of the plants. The average crop of Java is from 60,000 to 90,000 tons, and that of Brazil from 340,000 to 380,000 tons. Costa Rica and the other Central American states also export coffee.

it appears from the records of English health officers that some diseases have special seasons in which they are most likely to prevail, it is not shown that occasional variations in temperature have much influence in the matter. Scarlet fever is at its minimum from January to May, and at its maximum in October and November. Diphtheria is more evenly distributed through the year, and is most dangerous a little later than scarlet fever. Measles and whooping-cough seem to be somewhat aggravated by cold weather, but are most fatal in May and June. Hot weather is adverse to small-pox, and favorable to disorders of the bowels, particularly in children.

to catch trains is declared to be dangerous, not only on account of the immediate perils it involves, but also because it tends in the long run to shorten life. We—at least persons who have passed middle age—have only a certain amount of reserve force, and all that we draw upon in hurries is abstracted from that which should be distributed through the remainder of life. The secret of longevity is probably skill in so economizing the reserve of vital energy as to make it last out an unusual period. Persons who begin unusual exercises in youth may adapt their constitutions to the habit, and may thereby hold on to their full term of life; but this can not be done safely if one waits till mature age before beginning.