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The Disinfection of Streets and Sewers.—How some of the worthless by-products of chemical works might be turned to good account in disinfecting the streets of our American cities, is shown by Mr. H. G. Debrunner, in the Philadelphia Chemist and Druggist. He is led, by the results of experiment, to believe that street-mud and the sewer-water containing the same are the main factors in the distribution of contagious disease. This matter could be effectually disinfected, and that without extraordinary expense, by treating it with certain waste products, such as the mother-liquors of copperas aud alum. Many a factory would be glad to get rid of this refuse, and would give it away for nothing. With these disinfectants, diluted with water to the desired strength, the streets should be sprinkled; most of the waste substances are so powerful that they may be greatly diluted without losing their efficacy. In street-dust, the author has found, besides the usual inorganic bodies, a number of organic substances—as, for instance, glutinous matter coming from abrasions of the hoofs of cattle. This matter varies in quantity from one-half to five per cent., and in some dust taken from roads leading to stock-yards it has been found in the proportion of as much as fifteen per cent. It decomposes readily, especially in the presence of water, and microscopic examinations of aqueous extracts of the mud from such localities show living beings of the lowest classes of the vegetable and animal kingdom—algæ, fungi, and various forms of infusoria.

The Harpy Eagle.—The harpy eagle (Harpyia destructor), of which a sprightly description is given by Dr. Felix L. Oswald in the American Naturalist, has its native home in the forests of Southern Mexico. Its common English and its systematic name, as well as its Spanish title, Aquila real (king-eagle), and its old Mexican name of "winged wolf," fitly characterize the rapacity of this bird. It has a square, strong head, armed with a powerful bill that can without any special effort crush a man's finger-bones. Its broad, compact wings are moved by shoulder-muscles of enormous strength; and its stout legs, feathered to below the tarsi, terminate in claws of such extraordinary power and sharpness that they leave their marks on the tough leather of a Mexican saddle, like the bite of a wild-cat. Its plumage is so elastic, so compact, and so firmly imbricated, that buckshot, striking on the wings or the breast of the bird at a certain angle, glance off, or fail to penetrate to vital parts. The fully-grown hen measures about three feet from its crest to the base of the tail, and from six to seven feet from tip to tip of the outstretched wings. The male is somewhat smaller, but the strength of the bird in proportion to its size is altogether abnormal. A tame old harpy eagle once engaged in mortal-combat with a big shepherd-dog, and was only vanquished by a second dog that came to the assistance of his fellow. In a fight of ten minutes the first dog had received a deep gash in his throat (from which he soon bled to death), lost one of his eyes, and the bones of his skull and breast had been laid open in numerous places. In a fight between a harpy eagle and a Mexican lynx which had been crippled by a shot through its haunches, but was otherwise in good fighting condition, the bird was torn to pieces, but the lynx did not survive him many minutes, having been literally flayed from its shoulders to the tip of the nose. The following narrative shows the bird's tenacity of life: A Mexican miner, before daybreak one morning, in the mountains near Orizaba, surprised a pair of harpies, and with a cudgel knocked down one of them, which flew directly at his head. The miner now dispatched the bird as he thought, with a few well aimed whacks, and, shouldering his game, resumed his journey toward the valley. Half-way down the mountain-side he reached a steep cliff, and shifted his burden to his left shoulder, to use his right arm to better advantage. But at the most critical moment of the dangerous descent he suddenly felt the claws of the eagle at his neck, and, in order to save himself, had to drop his stick, which fell down the cliffs and into the bed of a mountain-torrent. Holding on to the bird with one hand, he managed to reach the foot of the precipice, where he seized the struggling-captive by the legs, and, swinging it up, dashed its head against a rock, till its convulsions had