one need dread at once to adopt the open-window system. Although few will believe it, until they try it, a wide open window does not produce a draught as does one slightly opened, and it is safer and pleasanter to go in for abundant fresh air than to try what might be called a moderate course. Many think that with an open window the heat of the fire is practically wasted. They do not know that the _radiant_ heat of the fire will warm the person it falls on even though the temperature of the room is very low. The Canadian hunter before his fire is comfortably warm, though the air around him may be a long way below zero. Extra clothing may be worn if any chilliness is felt. While the body is warm cold air has an invigorating effect on the lungs. Indeed, the body soon gets accustomed to the colder air, and those who practise keeping open windows winter and summer find that they do not require heavier clothing than those who sit with windows shut. A slight or even considerable feeling of coldness, when due to cold air and not to ill-health, will not harm. This is no new idea. Dr. Henry McCormac, of Belfast, father of the eminent surgeon, Sir William McCormac, wrote forty years ago:--"The mainly unreasoning dread of night air, so termed, is a great impediment to free ventilation by night. And yet day and night air is the same virtually, does not differ appreciably. The air by night, whether damp or dry, is equally pure, equally salubrious with the air by day, and calls not less solicitously for ceaseless admission into our dwellings. Air, ere it reaches the lungs, is always damp. Quite dry air is irrespirable. It needs no peculiar or unusual habitude in order to respire what is termed night air. Exposure to contact with the day air equally prepares us for exposure to the contact with the night air. We can multiply our coverings by night with even greater ease than we can by day, and with the most perfect certainty of producing and obtaining warmth. Good heavens! How is it that people are so wildly mistaken as if the great wise Deity, as he does by every exquisite and perfect adaption, did not intend that we should make use of the purest, sweetest air day and night always? The prospective results of breathing purest air by night are so infinitely desirable, the immediate enjoyment is so great that it only needs a trial to be approved of and adopted for ever.... Reasonable precautions--that is to say, adequate night coverings--being resorted to, no colour of risk to the lungs, even of the most delicate, can possibly ensue. For, it is stagnant air, air pre-breathed only, and not pure unprerespired air that makes lungs delicate. Although air, warmth, food, and cleanliness be cardinal conditions and essential to life, still the most important of all health factors is air--air pure and undefiled alike by day and by night.... The constant uneasy dread of taking cold, which haunts the minds of patients and their friends, is doubtless the one great reason