says (in the paper previously quoted), "Grounds for distrust in determining the purity of water are grounds for its rejection, especially when brought into comparison with water from a source of undoubted purity."
It has been objected that no water outside the laboratory is absolutely "pure;" that water ordinarily available for town-supply is only relatively pure, and that too high a degree of purity must not be expected, lest the cost of the works be too great a public burden. This is true, abstractly, yet who will have the temerity to draw the line and say: "Our town can and must stand such and such a death-rate, but no more; let us risk it and take our water from this contaminated pond close by, and let the death-rate be so and so, rather than spend so many thousands more in bringing pure living water from the everlasting hills miles away, and thus reduce our death-rate to the minimum!"
The question of cost should never for a moment weigh against the question of purity of quality. Foul, though apparently pure, water may be the cheaper in the beginning, but it will surely be the dearer to the community in the end, when it is remembered that health and life itself tremble in the balance. Cost and quantity should not be underrated, certainly, neither should quality. It is the frequent neglect of this latter element of calculation, in designing works for the water supply of towns, that results in the frightful epidemics usually and impiously attributed to the "mysterious dispensations of Providence," rather than to human ignorance, or cupidity, or negligence. Recently an English clergyman actually preached to his parishioners that a devastating fever among them was a visitation from God upon them in punishment for their sins, while at the same time a gentleman, writing to the authorities to complain of the water-supply, dipped his pen in, and wrote with water from the river instead of ink!
Setting aside now all other sources of water-contamination, let us see what the best authorities say would be the effect on the quality of drinking-water derived from agricultural lands enriched with organic manures, and especially that manure which consists largely of human excreta from privy-vaults and the contents of house cesspools.
Two propositions may here be stated that are perfectly sustained by proof:
1. Any organic matter will poison water, and is not removable except by boiling or distillation.
2. Human excremental matter is the most dangerous organic substance likely to be contained in privy-vaults or cesspools, and its virulence is largely increased when it consists partly of the excrementitious matter of cholera and fever patients.
We will take as an example a compactly-built town of some fifteen thousand inhabitants. Each habitation has its one or more privy-