Page:Popular Science Monthly Volume 63.djvu/139

Rh remain entirely wholesome and incapable of spreading disease. The radius of infection was likely to be very circumscribed. In cities, on the other hand, where the persons resorting to a particular well might be very numerous, the contamination of a single source could lead to disease and death, not merely in one or two families but in scores of families. Again, the greater liability to contamination to which a well in a densely settled region was exposed was an added menace and enhanced the peril to the city dweller from this source. The introduction of general public water supplies lessened to a considerable extent the latter evil and placed the city resident in a more advantageous position. The public water supply of large towns became on the whole purer than the water formerly obtainable by the private citizen, and since the supply was often brought from some distance, it was not liable to increased pollution as a direct consequence of the increase in the density of the city population. But on the other hand, the introduction of the public supply increased the danger from diffusion. Far greater numbers of people were affected. If the public supply became infected with a specific disease germ, the germ was distributed among much wider circles, and the infection became a momentous matter to the whole community. This in turn had the natural result that the attention formerly directed by the more intelligent members of the community to the care of their own private water supplies was now turned towards the public supply, and the problems of expert selection, supervision and control of the public supply began to receive the attention they deserved. There remained in many municipalities, however, so much inertia that this obvious duty was neglected or abandoned to the tender mercies of greedy politicians.

The conditions in many parts of the United States at the present day testify eloquently to the existence of this transition stage. In those sections, however, where it is the rule for proper care to be taken of the public water supplies the city death rate from typhoid fever is low, often lower in fact than in the surrounding country districts. In the year 1900, for instance, the typhoid fever death rate in the thickly populated 'Maritime District' of New York State, comprising chiefly the territory of Greater New York, with a population density of 1,535 per square mile, was only 2.0 per 10,000 inhabitants, while in the sparsely settled 'Adirondacks and Northern' district, with a population per square mile of 26, the reported death rate from typhoid fever was almost twice as great (3.9).

Theoretically, at least, the city ought to possess a decided advantage over the country in the matter of water supply. It ought to be possible for a large city to place its public supply under expert and specialized control, thus averting from the ignorant and careless members of