The problem of sewage disposal for a single house differs from the corresponding problem for a city chiefly in two ways: first, because in the city it is becoming, if it has not, indeed, already become, a necessity, and city authorities, though somewhat reluctantly, are willing to grant the necessary appropriation to secure engineering advice which will solve the problem in a scientific as well as economic fashion. In the case of a single house, whether a farm-house or a villa, the necessity of employing competent engineering advice has not been generally recognized, and no attempt has been made to solve the problem of sewage disposal in a scientific manner. Cesspools have been considered the only way of caring for sewage in places where a running stream was not available, or where attempts were made to protect such a stream from pollution, and while, in these last few years, crude attempts have been made to utilize the so-called septic tank, such attempts have generally been so unintelligent that the results have been anything but satisfactory. Since it has been understood that insects, such as flies and mosquitoes, play an important part in the transmission of disease, the danger of overflowing cesspools and of open ditches in which stagnant sewage is present, has been appreciated; also the higher standards of living which have made themselves felt throughout the rural community have demanded in farm-houses and country homes sanitary conveniences which have hitherto been wanting. Gradually every house is using more and more water for various purposes, and living conditions, which in the past tolerated a scanty supply drawn from a pump, are no longer endured. The increased water supply and the demands of extended plumbing mean a greater amount of sewage—so great an amount that, in many cases, soils which could receive and digest the waste waters from houses supplied by wells are clogged and made impervious by this greater amount. Further, the danger to wells from the infiltration of cesspools is more feared, and it is understood as never before that in order to maintain the highest degree of health in a family the drinking-water used must be above suspicion and not subject to contaminating influences in the vicinity. Again, communities are being aroused to the intrinsic value of maintaining streams in a pure condition—partly because of the value of fish and ice coming from the streams themselves, and partly on the broad ground that watercourses belong to the country as a whole, and must be kept pure for the sake of succeeding generations, not spoiled for them on account of the selfishness of a few at the present time.