Nowhere out of Laputa could there be serious thought of differentiating excremental performances into groups of diarrhœal and healthy.... It is excrement, indiscriminately, that must be kept from fouling us with its decay.... It is to be hoped that ... for a population to be thus poisoned by its own excrement, will some day be deemed ignominious and intolerable. And it is still opportune to draw attention to the terrible responsibility incurred by local authorities when they distribute a general supply of water to the inhabitants of their area without taking every possible precaution against contamination. The conveniences and advantages of public water supplies “are countervailed by dangers to life on a scale of gigantic magnitude”; and sanitary history, in the calamitous experience of Lincoln, Maidstone, and Worthing and of Lowell and other towns and districts, has given remarkable illustrations of the need for eternal vigilance. _Typhoid Fever_ With the differentiation of typhoid fever from typhus fever by Gerhard in Philadelphia in 1837, and by Stewart and W. Jenner in Great Britain in 1849, it became possible to associate the former with excremental, the latter with respiratory filth, “the non-removal of the volatile refuse of the human body.” The question still remained whether typhoid fever was producible by “emanations from decomposing organic matter,” whether it was “often generated spontaneously by faecal fermentation,” as contended by Murchison, who in 1858 proposed the name “pythogenic fever” for typhoid fever; or whether as indicated by the remarkable observations of William Budd of Bristol, the introduction of specific infection from a typhoid patient was needed to start a local outbreak. Gradually it became clear that specific contamination was necessary to start an outbreak or even to cause a single case of this disease, and between 1870 and 1880 a number of water-borne outbreaks were traced. It also gradually became evident that, however objectionable or even noxious might be the gaseous emanations from leaky drains or sewers, they did not cause typhoid fever or diphtheria. Hence the statement, for instance, of Oliver Wendell Holmes in 1862 (quoted for its historical interest by Dr. Sedgwick) that “the bills of mortality are more obviously affected by drainage than by this or that method of practice,” which expressed universal opinion when it was written, is now known to be accurate only when specific matter from drains contaminates milk or water supplies, or causes infection by actual contact. With the general recognition of the causal relation between impure water supplies and typhoid fever came the rapid provision of public supplies, on which, as already seen, large public expenditure was incurred; and to this fact is owing, in the main, the rapid reduction in typhoid mortality shown in the following statement: