We have heard a good deal lately about the policy of the open door, and recommend to our readers’ serious consideration the policy of the open window as much as possible by day and always at night. Unless the head of the bed is immediately by the window (and scarcely even then), it is practically impossible to catch cold when one is in bed and properly covered. To live under canvas, for instance, means to sleep almost invariably in a thorough draught. But those who have tried that delightful mode of life know that to catch cold under such circumstances is almost unknown; one is constantly wet and is usually in a draught, but one does not catch cold because these things in themselves do not produce a cold in a healthy person, and one’s health in such conditions is improved, because one has enough air and probably not too much food. The air itself is tonic, strengthening; it is largely because in civilised city-life we do not have enough that we are liable to colds. The passages to the lungs, with their lining of mucous membrane, and the lungs themselves, are clogged with impurities, and weak through a mild form of starvation. Feed them. Clean them. We do not, however, advise the ordinary city man deliberately to sit in a draught, though if that were the only plan of getting air it might be far better than his present procedure. Instead, we recommend him to look to his ventilators, and whenever he feels that the office is stuffy let him cut another or two, one low and one high; let him--and these remarks apply to all dwellers in houses--warm his offices by fires rather than hot pipes, if possible; for fires assist ventilation while they also give heat, but pipes are valueless except for heat. Furthermore, a screen of paste-board, or if light is wanted, of glass, can often be arranged so that a window may be opened without creating a draught at all; for though draughts are not, we think, so guilty in the way of cold-giving as their reputation would seem to justify, yet they are uncomfortable. But above all have windows open during sleep, that mighty friend of recuperation, when rest ought to be brought to every organ. And the natural rest to give the lungs is to supply them with plenty of pure air, so that their work is made easy for them. Nothing is commoner than long drowsiness and heaviness on waking, even after perfectly sufficient sleep, and for this nothing is more responsible than the fact that we have been breathing all night air which has been steadily deteriorating because drained of its oxygen. Let the windows be shut by all means, if you will, while you are dressing; but while sleeping, never.