The extent to which this system will be interfered with by frost, it is impossible to say. This will probably be less than would be supposed, for the reason that the ground would often be covered with snow, and that the sewage will have sufficient warmth to exert considerable thawing influence. Whenever the discharge of the liquid through irrigation pipes is shown to have become obstructed by freezing, it will only be necessary to divert the flow, and turn it into the surface gutter to be distributed over the ground. It is possible that in this case, as in the one which has been under my observation for six years past, there will be no interruption of the working because of cold; but, should the interruption become serious, I shall propose the planting of evergreen trees in parallel rows midway between the drains. The protection that would thus be afforded, both by the trees and by the drifting snow which they would gather, would probably keep the ground free throughout the winter. Incidentally to the chief advantage of this system, there will be, so long as the land is in grass, quite an addition to its product. * * * * * There are hundreds of villages, with and without a water supply, where the houses are too scattering and the street lengths too great to make it advisable that the cost of any form of public sewerage should be assumed. In all such villages, the public authority or the active influence of the village improvement association should be exerted to secure a regular and systematic adoption of some more perfect system for the private disposal of household drainage than is usual. Fortunately, the best system is the cheapest. No form of cesspool, no leaching vault, and no cemented tank, should be allowed under any circumstances. Neither should there be permitted any form of the old-fashioned out-of-door privy with a vault. Every household should be supplied with water-closets or well-arranged earth-closets, to which reference will be made below. [Illustration: FIG. 9.--SETTLING BASIN.]