The white vitriol, being a salt of zinc, might be supposed to possess the same virtues; and it would appear to do so from some facts[111] that were reported to me in the West Indies, and also from some trials made by me at St. Thomas’s hospital since I came to England. Though this is a medicine of very considerable powers, I do not mean to put it in competition with the bark, by proposing it as a substitute for it, or by representing it as superior to it in all circumstances; but only to propose it as a valuable subsidiary in particular cases. The account I have given is faithfully extracted from a diary of my practice; and were I to say more in its favour than the future experience of others may warrant, I should do more harm than service to its reputation. Many good medicines have had their characters hurt by being over-rated by the first proposers of them, who are naturally sanguine and partial, without, perhaps, intending to deceive. But when others find that their virtues do not come up to what has been asserted, they are apt to run into the other extreme, and explode them altogether; so that what was given out as good for every thing, is now found to be good for nothing[112]. CHAP. II. Of FLUXES. These seem to arise in the same circumstances, and to be owing to the same general causes, as fevers. They may, in some sense, be considered as fevers, attended with peculiar symptoms in consequence of a determination to the bowels, just as fevers in cold climates are sometimes attended with rheumatism and catarrh. We have seen, in the first part of this work, that the dysentery arose chiefly in those ships which had been subject to fevers. This determination to the bowels is owing to a variety of causes, but is chiefly connected with external heat; for it is most common in hot climates, and towards the end of summer or in the autumns of cold climates, owing probably to a greater acrimony of the secretions of the intestines, and particularly of the bile. Dysenteries arise in camps also at the same seasons, and in the same circumstances as bilious fevers[113].