Water is unquestionably the natural beverage of man; but any objection to the use of other beverages, founded on their artificial origin, I should at once repel by the same argument which has been adduced in defence of cookery, that we are to consider man as he is, not as he might have been, had he never forsaken the rude path of nature. I am willing to confess, that "the more simply life is supported, and the less stimulus we use, the better; and that he is happy who considers water the best drink, and salt the best sauce:" but how rarely does a physician find a patient who has regulated his life by such a maxim: He is generally called upon to reform stomachs, already vitiated by bad habits, and which cannot, without much discipline, be reconciled to simple and healthy aliment. Under such circumstances, nothing can be more injudicious than abruptly to withdraw the accustomed stimuli, unless it can be shown that they are absolutely injurious - a question which it will be my duty to investigate hereafter.

235. The qualities of water differ essentially, according to the source from which it has been obtained; and those accustomed to this beverage are sensible of differences which wholly escape the observation of less experienced judges. How far the existence of foreign matter injures its salubrity, has been a subject of much controversy: the truth, perhaps, lies between the extremes; those who insist upon the necessity of distillation for its purification, and those who consider every description of water as alike salubrious, are, in my opinion, equally remote from truth. That the presence of very minute quantities of earthy matter can become a source of disease, appears absurd; while it would be highly dangerous to deny the morbid tendency of water that holds putrescent animal or vegetable matter in solution, or which abounds in mineral impregnation.

236. The usual varieties of common water were classed and defined by Celsus, and modern chemists have not found any reason to reject the arrangement - "Aqua levissimapluvialis est; dein fontana, turn ex flu-mine, turn ex puteo; posthtec ex nive aut glacie, gravior his ex lacu; gravissima ex palude".

1. Rain Water

Rain Water, when collected in the open fields, is certainly the purest natural water, being produced, as it were, by a natural distillation. When, however, it is collected near large towns, it derives some impregnation from the smoky and contaminated atmosphere through which it falls: and, if allowed to come in contact with the houses, will be found to contain calcareous matter; in which case it ought never to be used without being previously boiled and strained. Hippocrates gave this advice; and M. Margraaf, of Berlin, has shown the wisdom of the precaution, by a satisfactory series of experiments.