In =country houses=, where there are no sewers, the best method of disposing of the house-slops is =subsoil drainage=. The house system may be the same as that already explained for city houses. The fluids are conducted by a pipe with tight joints to a =flush-tank= (Fig. 26) near the house. This tank is so constructed that it empties itself, by a siphon action, whenever it gets full, discharging all its contents in a very short time, and thus washing out thoroughly the pipes into which it empties. “The outlet-pipe from this tank is continued by a cemented vitrified pipe to a point about twenty-five feet farther away. Here it connects with a system of open-jointed drain-tiles, consisting of one main, fifty feet long, and ten lateral drains, six feet apart, and each about twenty feet long. These drains underlie a part of the lawn, and are only about ten inches below the surface” (Waring). It will be understood that the purpose of this method of drainage is to have the organic matter contained in the house-refuse appropriated by vegetation, and it must therefore be distributed within reach of the grass-roots. If water-closets are used, the following system is recommended in “The Sanitary Engineer”: Collect all the sewage of the house in a small and perfectly tight tank or cesspool, in which the paper and fecal matter soon become macerated by fermentation and reduced to a pulp. This tank should overflow into the flush-tank, the overflow-pipe dipping at least a foot below the point of discharge, to avoid the scum. The siphon of the flush-tank should be accessible by a man-hole, so as to be readily cleaned. If thus arranged, and if no roots of trees are in the soil, the distribution-pipes will not clog for a year or more, sometimes not for ten years. Pipes should be laid at a depth of eight inches, with a slight and uniform descent of not over six or eight inches in one hundred feet. Branches from a four-inch main to the two-inch distribution-pipes should lead from the bottom of the former, instead of from the side, as in ordinary drain connections. There should be a grease-trap (see “Explanatory Remarks,” 3) attached to the kitchen waste-pipes, in order to prevent clogging of the tanks and pipes by the congelation of fat. _Bad Odors._ =When bad odors in a house are traceable to the drainage, they will usually be found to be due to one or more of the following causes=: 1. =To faulty construction.= (_a._) =Drains.=—These may be made of brick or stone and cement. Such materials are pervious to gases, even when sound, and are peculiarly liable to be channeled by rats, especially where an iron or lead pipe enters them. Such a drain should be replaced by an iron one.