Cleanliness, we are told, is akin to godliness, and dirt may be called a child of the evil one. The dust and smoke of our towns are responsible for more deaths than war. It is well known that dusty occupations are dangerous, the danger increasing with the hardness and sharpness of the dust All dust is more or less injurious to the respiratory organs. Many "colds" are caused by breathing dust-laden air, and hay-fever is probably due to the inhalation of pollen grains.

But household dirt is complex. It includes inorganic matter of various kinds, such as fine particles of sand, clay, metals, and (more important than these) defiling soot; and also organic matter, the products of putrefaction and decay or emissions from living plants and animals, and comprising myriads of organisms, some of which may produce specific diseases in the persons breathing them or swallowing them with their food.

Of all the forms of household dirt, none is probably more detested by the good housewife than soot. The dry dust blown from a country road is what a child calls "clean dirt"; it is easily swept or brushed away. But the smoky air of towns defiles wherever it floats. No wonder that mistress and maids fast-bind windows and doors to exclude it, preferring close and stuffy rooms rather than admit the outer air with its concomitant filth. The purification of the air is a necessary feature in all schemes of house-ventilation in towns.

But since dirt is so prevalent, it behoves the architect to avoid as far as possible all ledges, nooks, and crevices, and all unseen spaces which could give it lodgment. Considered in the light of cleanliness, the ordinary floor, with its plastered ceiling below and gaping boards above, is radically wrong; so also is the confined space so often provided between the ground-layer and ground-floor; so also are lath-and-plaster partitions, hollow walls, and indeed all details of building-construction which provide spaces invisible and inaccessible to the householder. Sooner or later dirt finds its way to these dark places, and vermin breed and wander there, safe from the housemaid's broom and the cat's eager paw.

Floor-boards and blocks, skirtings, and other wood should be thoroughly seasoned, otherwise they will shrink and the joints be filled with dirt Indeed, for many purposes wood is now frequently superseded by plaster of Paris or cement, and with manifest advantage, as in the case of skirtings and architraves. Plaster cornices with deep hollows and ledges and " bold" enrichments are an abomination. As far as cleanliness is concerned, gas-fires and gas-stoves are better than coal-fires, and the electric light is the best of all illuminants.

Compromise must, of course, enter into the construction of a house as into its plan and design. Cleanliness must be considered in relation to temperature and dryness and the other qualities desirable in dwelling-houses, but it is abundantly clear that sufficient thought has not hitherto been bestowed by house-builders on this important point.

The ideal house in respect of cleanliness is that into which air cannot enter till it has been freed from all impurities; which is built of such materials and furnished in such a manner that the production and retention of dust and dirt within it are reduced to the smallest limits; which burns its own smoke, and carries off all products of combustion, trituration, and decay as rapidly as they produced, which is constructed so that there are no dark corners, no ledges, angles, and crevices in which dirt can linger; and, finally, which has an abundant supply of pure water, and lends itself to easy and rapid cleansing. Especially in bath-rooms, water-closets, sculleries, kitchens, and other rooms in which much water is used and more or less dirty work performed, the materials should be smooth and impervious; wood and common plaster should give place to concrete, glazed bricks or tiles, and cement. Even the joints of glazed brickwork are now often covered with impervious enamel paint.

In the construction of hospitals particular care is exercised in order that dust and germs may have no lodgment; the angles of floors,1 walls, and ceilings are rounded; the moulds of windows, doors, and skirtings are designed without deep hollows; the materials used in construction are as hard and impervious as and there is light everywhere. The principles which govern hospital construction should l>e applied to the construction of houses, for sooner or later every house is a hospital on a small scale, and the life or death of the stricken occupant may depend on its sanitary condition.