Consumption is the disease which carries off a fifth or more of the persons born in Britain, owing in part, no doubt, to the changeableness of the climate, but much more to the faulty modes of warming and ventilating the houses. To judge of the influence of temperature in producing this disease, we may consider--that miners who live under ground, and are always, therefore, in the same temperature, are strangers to it; while their brothers and relations, exposed to the vicissitudes of the weather above, fall victims--that butchers and others who live almost constantly in the open air, and are hardened by the exposure, enjoy nearly equal immunity--that consumption is hardly known in Russia, where close stoves and houses preserve a uniform temperature--and that in all countries and situations, whether tropical, temperate, or polar, the frequency of the disease bears relation to the frequency of change. We may here remark, also, that it is not consumption alone which springs from changes of temperature, but a great proportion of acute diseases, and particularly of our common winter diseases. In how many cases has the invalid to remark, that if he had not taken cold in such a place, or on such an occasion, he might yet have been well. * * * The following considerations present themselves in this place.--Small rooms in winter are more dangerous to health than large ones, because the cold air, entering towards the fire by the doors or windows, reaches persons before it can be tempered by mixing with the warmer air of the room--Stoves in halls and staircases are useful, because they warm the air before it enters the rooms; and they prevent the hurtful chills often felt on passing through a cold staircase from one warm room to another. It is important to admit no more cold air into the house than is just required for the fires, and for ventilation; hence there is great error in the common practice of leaving all the chimneys that are not in use, quite open; for each admits as much air as a hole in the wall would do, or a pane deficient in a window. Perhaps the best mode of admitting air to feed the fires is through tubes, leading directly from the outer air to the fire-place, and provided with what are called throttle-valves, for the regulation of the quantity; or the fresh air admitted by tubes may be made first to spread in the room, having been warmed during its passage inwards, by coming near the fire.--In a perfectly close apartment, ventilation must be expressly provided for by an opening near the ceiling, to allow the impure air rising from the respiration of the company to pass away at once; but with an open fire, the purpose is effected by the frequent change of the whole air of the room which that construction occasions.