This is a point on which many people are terribly careless. Not only are many otherwise well-built and handsome-looking houses placed in situations naturally unhealthy from a difficulty in draining them, but many, erected in positions where drainage is easy, are left almost to the efforts of nature. This, however, is not by any means the worst of it. Many people make a regular practice of throwing all slops and refuse just outside the kitchen door, where they are left to pollute and poison the atmosphere till cleaned away by those friendly scavengers, the ducks and pigs.

"The most efficient cause of dampness in the air is the permanent retention of moisture on or near the surface of the ground, as in low grounds in which clay prevails, and where water accumulates or is imperfectly drained off, and where evaporation is retarded by the shade of many trees or of high rocks or hills. But, independently of soil, a house may be damp from its own materials, which, as in those built of limestone or marble, are constantly impregnating the contained air with humidity. Wet weather and damp winds are less injurious causes of humidity, because less permanent, but their influence is often manifest during their continuance, and always most so in localities that are damp from other causes." So injurious are these damp winds considered, that in Lower Canada it is quite common to see the outside of stone and brick houses boarded up on those sides exposed to the Easterly winds.

"In districts where lime is obtainable, much benefit may be obtained in damp houses, by keeping large pans of quicklime in several apartments, especially those of the basement and ground-floor. This is an excellent precaution against malarious and infectious diseases; its utility has long been known in preventing meat from becoming soon tainted in a damp larder."

"To diminish the dampness of clay and marshy soils in the immediate vicinity of dwellings, much may often be done by an efficient system of covered drainage; by the removal of superfluous trees and shrubs; and where practicable, by covering the surfaces which are most commonly wet, with light sand, gravel, brick and mortar rubbish, or some similar light and porous material, which may form an artificial superstratum, and intercept the influence of the damp gronnd. The insalubrity of many low parts of London ("England), especially in Pimlico and Westminster, has been wonderfully diminished by the latter expedients." The effect of drainage in stopping the regular prevalence of Ague has been very conspicuous in many places in Canada, which formerly suffered much from this complaint; Chatham, on the Thames, and the eastern portion of the city of Toronto, where Ague is now scarcely heard of, are prominent examples.