The devitalising influence of extreme _cold_ is well known. Its effects are more particularly seen in young children and the very old, who require to be carefully tended during severe and long-continued cold weather. Dry, cold weather, with the temperature near the freezing point of water, and a cutting east wind prevailing, is not uncommonly described as “bracing.” This is so far from being the case, that it requires all the vital powers of the strong and healthy to resist its depressing influence, and the feeble of both extremes of age succumb. CHAPTER XVII. TRADE NUISANCES. Many occupations are the source of considerable danger to the workers engaged in them. They are chiefly injurious by the inhalation into the lungs of some foreign agent, which produces serious local inconveniences and irritation, and may be also absorbed into the circulation and produce more remote effects. The injurious agents may be classified under four heads:— (1) Insoluble particles or dust. (2) Soluble or partially soluble substances. (3) Injurious gases or vapours. (4) Effluvia from offensive trades. It is evident that, as regards the effluvia named under (4), they might generally be included under the three previous heads, though it is convenient for our present purpose to keep them separate. The occupations in which dust and soluble substances are productive of injurious effect have already been described, pages 107 to 109. Injurious gases and vapours have received consideration on pages 111 and 112. The special offensive trades still require attention. =Offensive Trades.=—The legal enactments relating to offensive trades are contained in sect. 112 of the Public Health Act, 1875, which states, any person who, after the passing of this Act, establishes within the district of an urban sanitary authority, without their consent in writing, any offensive trade, that is to say, the trade of— Blood boiler, or Bone boiler, or Fellmonger, or Soap boiler, or Tallow melter, or Tripe boiler, or any other noxious or offensive trade, business, or manufacture, shall be liable to a penalty not exceeding fifty pounds in respect of the establishment thereof, and a penalty not exceeding forty shillings for every day on which the offence is continued. These provisions can only be enforced in rural districts with the sanction of the Local Government Board. The “other noxious or offensive trades,” in order to be brought within the operation of the section, must be analogous to those which are specially enumerated. The most exhaustive and authoritative report on this subject is by the late Dr. Ballard, whose report is largely quoted in the following remarks.