It should always be remembered that the principal advantages of this closet are that where it is used we are able to collect all of the evacuations, which may then be properly deodorized with soil or ashes, and that it may then be finally disposed of in such a way that it cannot be reached by hogs or other animals; of very great importance also is the screening of the closet, since only in this way is it possible to prevent flies from gaining entrance to the fecal material in the receiving pails. _Water supply._[2]--In the location of houses and schools an eye should always be had to selecting a site where it is possible to obtain good, pure water. To those fortunate dwellers in the mountainous regions of our country this is usually a matter of little difficulty, since it is always possible to find a location in the neighborhood of which the purest spring water may be obtained. In less favored regions the well becomes the main reliance, while cisterns are used in some portions of our country, in which water is collected during the rainy seasons of the year. Of the two, the former is undoubtedly to be preferred, provided a pump be used instead of the old fashioned bucket. The writer is strongly of the opinion that a very large proportion of the contamination to which sources of water-supply are subject comes from the bucket being drunk from or handled by persons with contagious diseases, or from germs being blown into the well with dust, or carried in by means of insects and small animals. It is inconceivable that any appreciable amount of contamination from the surface can reach the underground streams that supply wells in localities that are thinly populated, though it is unquestionably true that a well might be infected as a result of the entrance of surface-water where its top is not properly protected. On the other hand we have in an open well or cistern every facility afforded for the entrance of bacteria.