All impurities should be removed from the sick-room, as they are liable to vitiate the atmosphere; and all clothes and utensils which have been used by the patient should be immediately put among warm water, and left there till a convenient season occur for their being thoroughly cleansed. When the patient is in a state to bear the fatigue of being removed for part of the day to another chamber, advantage should be taken of his absence from his bed-room, to ventilate the apartment, by throwing open the doors and windows, to expose his bed and body clothes to the free action of the air, and to cover the sickly smell frequently present in sick chambers, by the burning or dissemination of some fragrant substance in the atmosphere. CORRECTION OF VITIATED AIR. The effluvia which are wont to arise in sick-rooms, are sometimes so very strong, especially where little attention is paid to cleanliness and ventilation, as to fasten most tenaciously to the contents of the apartments, and to impart to them a most disagreeable and sickly odour, not immediately removeable upon the establishment of currents of air obtained by opening the doors and windows. These effluvia, for the most part, are cognizable to the organ of smell, and they have long been, and are still, vaguely designated “Contagion,” “Infection,” and the like. Where effluvia are not recognised by the organ of smell, there are many good reasons for believing, notwithstanding that circumstance, that they may be present in rooms which contain, and which have lately contained, sick persons. Well authenticated cases are on record, where persons in health have inhabited apartments which, at a former period, contained sick persons, and have been attacked with disease in such a manner as to leave little doubt of the presence of unwholesome effluvia, and of their having been the efficient agency in the production of the evil. These instances have occurred, where it is impossible to suppose that the effluvia could have been commingled with the atmosphere during the whole interval, often amounting to years, from the period of the removal of the sick, to that of the taking up of their abode there by those who have suffered. The period during which the apartment has been uninhabited has, on many occasions, been too long to admit of the opinion that the atmosphere has not been again and again changed. It would therefore appear, that not only the atmosphere becomes infested, on those occasions, with effluvia, but that the walls, the furniture, and the floors may likewise become impregnated with them. It is consonant with experience to admit, that solid bodies occasionally combine with, or imbibe, or attract gasiform products, or that aeriform or vaporic agents adhere to solid substances.