Page:Treatise on poisons in relation to medical jurisprudence, physiology, and the practice of physic (IA treatiseonpoison00chriuoft).pdf/451

 *tematically ventilated, the external air being freely admitted when the weather will allow, and particular currents being established, by which floating particles are carried away in certain invariable and known courses. Miners and others who work at furnaces in which lead is smelted, fused, or oxidated, should be protected by a strong draught through the furnaces. According to Mr. Braid, wherever furnaces of such a construction were built at Leadhills, the colic disappeared; while it continued to recur where the furnaces were of the old, low-chimneyed form. Manufacturers of litharge and red-lead used formerly to suffer much in consequence of the furnaces being so constructed as to compel them to inhale the fine dust of the oxides. In drawing the furnaces the hot material is raked out upon the floor, which is two or three feet below the aperture in the furnace; and the finer particles are therefore driven up and diffused through the apartment. But this obvious danger is now completely averted by a subsidiary chimney, which rises in front of the drawing aperture, and through which a strong current of air is attracted from the apartment, the hot material on the ground performing the part of a fire.

In white-lead manufactories a very important and simple improvement has been effected of late in some places by abandoning the practice of dry-grinding. In all manufactories of the kind, the ultimate pulverizing of the white lead has been long performed under water. But in general the preparatory process of rolling, by which the carbonate is separated from the sheets of lead on which it is formed, continues to be executed dry. This is a very dangerous operation, because the workmen must inhale a great deal of the fine dust of the carbonate. In a white-lead manufactory which formerly existed at Portobello, the process was entirly performed under water or with damping; and to this precaution in a great measure was imputed the improvement effected by the proprietor in the health of the workmen, and their superior immunity from disease over those of Hull and other places, where the same precaution was not taken at that time. The only operation latterly considered dangerous at the Portobello works was the emptying of the drying stove, and the packing of the white lead in barrels; and the dust diffused in that process was kept down as much as possible by the floor being maintained constantly damp. By these precautions, by making the workmen wash their hands and faces before leaving the works for their meals, and by administering a brisk dose of castor oil on the first appearance of any complaint of the stomach or bowels, the manufacturer succeeded in extirpating colica pictonum entirely for several years.—This trade continues to be a very pernicious one in France; for no fewer than 266 cases of colic were admitted into the Parisian hospitals in 1841 from the white-lead manufactories in and near the capital. Yet facts are not wanting there to prove that with proper care the disease may be all but extirpated. A French manufacturer, whose workmen at one time suffered severely, had no case of colic among them for nine years after breaking them in to the observance of due precautions. Another says, from his