A deep trench saves labor, and places the refuse in the most immediately safe position, but a buried mass of refuse will take a long time to decay; it should not be disturbed, and will taint the adjacent soil for a long time. This is of less consequence in a merely temporary encampment, while it might entail serious evils in localities continuously inhabited. The following plan of trench has been adopted as a more permanent arrangement in Indian villages, with the object of checking the frightful evil of surface pollution of the whole country, from the people habitually fouling the fields, roads, streets, and watercourses. Long trenches are dug, at about one foot or less in depth, at a spot set apart, about 200 or 300 yards from dwellings. Matting screens are placed round for decency. Each day the trench, which has received the excreta of the preceding day, is filled up, the excreta being covered with fresh earth obtained by digging a new trench adjoining, which, when it has been used, is treated in the same manner. Thus the trenches are gradually extended, until sufficient ground has been utilized, when they are plowed up and the site used for cultivation. The Indian plow does not penetrate more than eight inches; consequently, if the trench is too deep, the lower stratum is left unmixed with earth, forming a permanent cesspool, and becomes a source of future trouble. It is to be observed, however, that in the wet season these trenches cannot be used, and in sandy soil they do not answer. This system, although it is preferable to what formerly prevailed--viz., the surface defilement of the ground all round villages and of the adjacent water courses--is fraught with danger unless subsequent cultivation of the site be strictly enforced, because it would otherwise retain large and increasing masses of putrefying matter in the soil, in a condition somewhat unfavorable to rapid absorption. These arrangements are applicable only to very rough life or very poor communities.