"As there is now no doubt that typhoid-fever, cholera, and dysentery may be caused by water rendered impure by the evacuations passed in those diseases, and as simple diarrhoea seems also to be largely caused by animal organic [matter in] suspension or solution, it is evident how necessary it is to be quick-sighted in regard to the possible impurity of water from incidental causes of this kind. Therefore all tanks and cisterns should be inspected regularly, and any accidental source of impurity must be looked out for. Wells should be covered; a good coping put round to prevent substances being washed down; the distances from cess-pools and dung-heaps should be carefully noted; no sewer should be allowed to pass near a well. The same precautions should be taken with springs. In the case of rivers, we must consider if contamination can result from the discharge of fecal matters, trade refuse, &c." Now, suppose all such precautions have been disregarded. Suppose, as is most usual, that the well is dug near the kitchen-door,--probably between kitchen and barn; the drain, if there is a drain from the kitchen, pouring out the dirty water of wash-day and all other days, which sinks through the ground, and acts as feeder to the waiting well. Suppose the manure-pile in the barnyard also sends down its supply, and the privies contribute theirs. The water may be unchanged in color or odor: yet none the less you are drinking a foul and horrible poison; slow in action, it is true, but making you ready for diphtheria and typhoid-fever, and consumption, and other nameless ills. It is so easy to doubt or set aside all this, that I give one case as illustration and warning of all the evils enumerated above.