It is another important question for practice, how far and in what manner malaria can be conveyed by the winds to places where it is not produced, so as to act in exciting disease. That it is conveyed to certain distances by winds is amply proved by an abundant experience, and I may first detail a few of the most useful particulars as to this fact. In Italy and Greece, it is observed, that where long valleys terminate on sea shores, on which the exits of the rivers are swampy, it is an [p045] effect of the sea breeze, by crossing such marshy ground, to convey the malaria up into the interior country, to considerable distances, and to places which are in themselves not insalubrious. Thus, also, does such a breeze, especially when it is a warm wind, convey the poison up the acclivities of hills, even to a considerable range of distance or elevation; a process facilitated by the natural tendency of such winds to ascend. And as a striking proof of this migration of malaria, it appears from Capt. Smyth’s statistical account of the insalubrious villages in Sicily, that out of more than seventy, about one-half are not seated near or on lands producing this substance, but on acclivities, at varying distances—thus receiving it through migration. The same is remarked by Montfalcon of many towns in France; while in some, the place at a distance is even more unhealthy than that which is immediately situated in the marsh itself: and in our own country, this is equally said to be true of the backwater at Weymouth, and of the marshes of St. Blasey in Cornwall, acting more powerfully at some distance than in the immediate spot. With respect to the absolute distance to which the malaria can be conveyed, it is yet an obscure circumstance, or at least the maximum has not been fixed; but it is at least ascertained that the convent of Camaldoli receives it from the Lake Agnano, at a distance of three miles; while from certain naval reports, a distance of five miles has been proved to permit its transmission,—and from an evidence that cannot be doubted, inasmuch as it was the sudden breaking out of fever in a healthy ship, anchored at that distance from the shore, on the coming off of the land wind, attended by its peculiar and well-known smell.