ch 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.

With a view to have the most perfect security against cold blasts and
fluctuation of temperature in rooms intended for invalids, and still to
retain the so much valued appearance of the open fire, a glazed frame or
window may be placed at the entrance of the chimney, so as completely to
prevent the passage of air from the room to the fire. The close room
will then be warmed by the fire through the glass, as a green-house is
warmed by the rays of the sun. It is true, that the heat of combustion
does not pass through glass so readily as the heat of the sun; but the
difference is not important. The glass of such a window must, of course,
be divided into smal