quired to be tight and properly covered, so that no part of their contents will escape into the street during transportation to boats or cars; and the storage of this material in any part of the city is no longer tolerated. While so large a number of horses (estimated at sixty thousand) are in daily use for business and pleasure, the necessary stables and refuse must continue to be a subject of constant sanitary care and attention.
6. Offensive Trades.—The business pursuits commonly called "offensive trades" are those which, if conducted carelessly and without the proper machinery and the necessary chemical appliances, become a nuisance detrimental to health. Twenty-five years since there were no proper public or official supervision and control of these pursuits, and they were only restrained from vitiating the atmosphere with smoke, dust, and foul odors by an appeal to the courts and by tedious and expensive litigation. Prompt attention to all complaints, frequent inspections, orders to discontinue business unless conducted without offense, and a vigorous enforcement of the health laws by the sanitary authorities, have accomplished the desired object. Mechanical and chemical devices have been successfully introduced whenever necessary, and it has been completely demonstrated that there is no business pursuit of importance which can not be conducted inoffensively in a large city, if the buildings used are properly constructed, the machinery and methods are thoroughly scientific and practical, and due care and supervision are constantly exercised. The manufacture of illuminating gas, prolific of odors if conducted without the necessary care and expense, has been a subject of frequent complaint, and although efforts for the public relief have often encountered a vigorous resistance,-fortified by corporate wealth and the necessity and universal use of the product, the business has been deprived of its most objectionable features, and is comparatively free from offense. The utilization of the various parts of slaughtered animals not used for human food and the methods employed are among the most remarkable of modern sanitary improvements. The fat, which was formerly melted in open kettles, is now rendered in air-tight tanks; the blood which defiled the public sewers, and the offal, from time immemorial a disgusting nuisance, are converted into fertilizers; and the bones and other refuse animal material, by the aid of applied chemistry, have become useful and valuable as commercial articles. It is unnecessary to enumerate the great variety of business pursuits which formerly afflicted the community with smoke, dust, and foul or offensive odors, and which are now conducted without offense or complaint. Only one trade has been hopelessly ruined by sanitary reform during the last quarter of a century; the ancient guild of hereditary night scavengers, the terror of belated, sleep-
