Page:Popular Science Monthly Volume 31.djvu/883

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waterfall, and others cutting out separate channels to the great gorge, some four hundred feet deep and sixteen miles long, worn in the solid granite. These streams form many rapids, and, when the river is half full, rise and form over a hundred separate cascades, unsurpassed for beauty and picturesque grandeur. When the river is full, many of them join to make one mighty sheet of water, rivaling the great Niagara, as it pours into the abyss nearly four hundred feet below. At low water, the only time it can be approached, the Hercules Fall is one hundred and sixty-five feet high, with several smaller falls at the sides, which are three hundred and fifty feet high, and are caused by the same water before it reaches the main fall."



Pertinently to an expression of doubt by Mr. David A. Wells in one of his articles on Mexico, as to the Aztecs having knowledge or making use of metal tools, Mr. W. W. Blake, in the "American Antiquarian," mentions as being on exhibition in the Archæological Rooms of the National Museum of Mexico, idols, beads, and engraved clasps of gold; lip-ornaments and other articles of silver; numerous tools, weapons, and ornaments of copper; and "chopping-knives" of copper, which are supposed to have been used as money.

Nine tenths of wild animals in confinement are said by a medical writer to be subject to heart-disease; but all animals have their peculiarities. Elephants are subject to many diseases, the most common and fatal of which is rheumatism. Monkeys and baboons generally die from bronchial affections and heart-disease, and suffer much from typhoid fever. Animals of the feline race are most subject to dysentery and heart-disease; and their prey, deer, antelopes, etc., are most liable to the same afflictions. Animals of the canine tribe are the healthiest, but too many wolves must not be kept together, or they will eat one another.

Dr. R. W. Shufeldt believes that the veterinary staff of our army needs improvement, and has suggested a plan for its reorganization, with a corps of officers carefully chosen. Thus properly organized, it could form an invaluable nucleus on which to build in time of war; in time of peace could do service to science by making comparative studies in diseases and injuries among all the domesticated animals; could more fully develop the morphology and physiology of our mammalian fauna—a work in which there is need for immediate action before some of the types shall become extinct.

In a paper on "Indicative Plants," Dr. R. W. Raymond considers a connection which is reported to exist between certain plants and the metallic contents of the soil on which they grow. Among the instances cited are the zinc violet (Viola calaminaria), of the Calamine Hills of Rhenish Prussia and Belgium; the lead-plant (Amorpha canescens), believed by American miners to grow only in localities containing galena; and the silver-plant (Eriogonum ovalifolium), which is regarded as a sign of silver-ores. The theories on this subject, if there be any, still lack the essential elements of verification.

General Prjevalsky is to be presented by the Imperial Scientific Society of St. Petersburg with a gold medal which has been specially struck in his honor by order of the emperor. It bears on the obverse the initials of the recipient, and on the reverse the inscription, "To the first student of the natural history of Central Asia."

Indian botanists report upon a plant which has the singular property of destroying the taste of sweetness. It is an asclepiad, and is called Gymnema sylvestre. After chewing a few of the leaves for a short time, if sugar be taken, the palate is found to have become insensible to all of its peculiar qualities, and it will have no more taste than sand. General Ellis has found that the Gymnema has also the property of abolishing the power of enjoying a cigar. It also destroys the bitter taste of quinine; but it does not affect pungent and saline things, astringents, and acids. The peculiar property of the leaves is dissolved out by alcohol, and appears to reside in an acid which is called gymnemic acid.

The Swedish count, M. Björnstjerna, suggested more than forty years ago, in a book on "The Theogony of the Hindoos," that, as both poles must have been cooled to a suitable temperature at the same time, the earth might have been peopled from the north pole with its white races, and from the south pole with its colored races.

Observations made at the late South Kensington Aquarium upon the effect of temperature on fish, show that the dogfish, mullet, conger, skate, flounder, bass, cod, trout, catfish, pike, and carp are extremely hardy, and can exist in a temperature ranging from 34° to 71°. The gurnard, wrasse, bull-head, sole, bream, crayfish, blennie, perch, dace, tench, minnow, chub, roach, and gudgeon are sensitive to extremes of temperature.