The question of drainage and water supply of cities, should take the precedence of every other question, for upon its proper solution depends thousands of lives. Those in authority should understand its importance, and feel the pressing necessity of more thorough sanitary work. Hygiene is not only a subject of scientific interest to the medical man, but its problems and discoveries ought to be of great practical importance to political economists and legislators, who usually occupy themselves with subjects which benefit the common people very little. It appears that the best engineering talent, and great amounts of money, have been employed, to furnish cities and towns with _inexhaustible supplies of water without sufficient regard to quality_. To economically furnish water in ample quantity, is an object of great importance; but it is of more consequence that the water obtained is not contaminated by sewers, cess-pools, and surface drainage to such an extent that disease and death shall be scattered broadcast; among those who drink the water. There are those who claim that a small proportion of sewage in drinking water does not necessarily prove deleterious to health. The English Rivers’ Pollution Commission published conclusions based on the examination of some two thousand samples of water claimed to be drinkable; condemning river water because it is liable to contamination from drainage of cultivated land, towns and manufactories. According to their decision “the admixture of even a small quantity of the infected discharges (of persons suffering from cholera or typhoid fever), with a large volume of drinking water, is sufficient for the propagation of those diseases among persons using such water.” Dr. Folsom, in the report of the Massachusetts State Board of Health, states that “excessive dilution simply diminishes the chances of danger from any particular tumblerful.” To show how disease may be transmitted in dilute sewage and that disease germs are not exterminated by diffusion through a large body of running water, Dr. E. D. Mapother, of Dublin, reports forty cases of typhoid fever occurring in a hospital which received its supply from a river. The cause was traced to some barracks twenty-five miles higher up, from which typhoidal dejections had been emptied through drains into the river. The following classification of drinkable waters which was made by the English commissioners, should be received by us as entirely trustworthy. _Wholesome_—Spring water, deep well water, and upland surface water. _Suspicious_—Stored rain water, and surface water from cultivated land. _Dangerous_—River water to which sewage gets access, and shallow well water.