A recent writer raises the inquiry, whether the community would not gain in health by the demolition of all dwelling-houses. That is, he suggests the question, whether the evils from foul air are not so great and so constant, that they countervail the advantages of shelter. Consumptive patients far gone have been known to be cured by long journeys, which have required them to be day and night in the open air. Sleep under the open heaven, even though the person be exposed to the various accidents of weather, has often proved a miraculous restorer after everything else had failed. But surely, if simple fresh air is so healing and preserving a thing, some means might be found to keep the air in a house just as pure and vigorous as it is outside. An article in the May number of "Harpers' Magazine" presents drawings of a very simple arrangement by which any house can be made thoroughly self-ventilating. Ventilation, as this article shows, consists in two things,--a perfect and certain expulsion from the dwelling of all foul air breathed from the lungs or arising from any other cause, and the constant supply of pure air. One source of foul air cannot be too much guarded against,--we mean imperfect gas-pipes. A want of thoroughness in execution is the sin of our American artisans, and very few gas-fixtures are so thoroughly made that more or less gas does not escape and mingle with the air of the dwelling. There are parlors where plants cannot be made to live, because the gas kills them; and yet their occupants do not seem to reflect that an air in which a plant cannot live must be dangerous for a human being. The very clemency and long-suffering of Nature to those who persistently violate her laws is one great cause why men are, physically speaking, such sinners as they are. If foul air poisoned at once and completely, we should have well-ventilated houses, whatever else we failed to have. But because people can go on for weeks, months, and years, breathing poisons, and slowly and imperceptibly lowering the tone of their vital powers, and yet be what they call "pretty well, I thank you," sermons on ventilation and fresh air go by them as an idle song. "I don't see but we are well enough, and we never took much pains about these things. There's air enough gets into houses, of course. What with doors opening and windows occasionally lifted, the air of houses is generally good enough";--and so the matter is dismissed.