whole cutaneous surface, while the lungs and stomach are left unprotected. Although, as has been fairly acknowledged, we do not know the essential constitution or intïmate nature of Malaria; yet, we have ascertained certain of its qualities with sufficient distinctness, to have deduced many useful, practical regulations concerning it. It is now generally assumed that Malaria is so weighty as not to rise above a given height in the atinosphere; nay, some have gone so far as to assign this limit with a singular exactness of measurement.

But the very authorities by whom these statements are offered present us, at the same time, with so many and such forcible exceptions to their correctness, that we are entitled to withhold our full credence from the doctrines they would inculcate. Thus De Lisle, in tracing the special degrees of liability of different towns and villages in the neighbourhood of the Pontine Marshes, after drawing the inference "that the limit to which these miasmata are confined, is somewhere between two hundred and eight and three hundred and six yards above the level of the places from which the poison issues"-goes on to admit "that he has reason to believe that it cannot be fixed in an absolute manner, and that it varies from year to year according to the heat, the wind that blows, and also the intensity and duration of both;" giving, as an example of this irregularity, Velletri, which is higher than Sezza, the latter being healthy, the former subject to Malaria diseases.

We have before remarked, that we consider the doctrine of the close affinity, exhibited by Malaria, for moisture in its various forms, to be perfectly established. We look upon this affinity as absolute, essential and exclusive in its influence, insomuch, that Malaria in an entirely dry state, altogether uncombined with moisture, would be totally inert and innoxious. Now, as far as moisture may be carried up into the thinner regions of the atmosphere, in any notable degree of density, so far may Malaria also rise upward, retaining its noxious powers; but, after a certain extent of dilution, or diffusion, or dispersion of the vapour, with which it has been combined, it loses that concentration necessary, as we formerly maintained to the establishment of its poisonous operation.

This, then, is the true advantage of elevation; not that the miasma cannot reach a lofty point, but that it of necessity becomes less and less concentrated while rising, and that the chances of its dispersion are infinitely multiplied.

Much has been said as to the liability of its progress to be impeded by a great variety of obstacles. The interposition of a forest, a mountain, and a high wall, a tent cloth, nay, of a

cloak, a mantle, a gauze pavilion, a veil, a silk handkerchief, has been supposed competent to preserve us from the pernicious effects of air, charged with this effluvium. Two explanations have been offered to account for these alleged facts. The first depends upon the peculiar coarseness of the miasmatic particles which is supposed to be so great as to prohibit their passage through many apertures, which admit odorous atoms and air, as a tent cloth, a cloak, a mantle, &c. The second maintains a chemical change, to be effected within some of these barriers by the exhalations from the lungs and skin collected there, upon the Malaria which penetrates within the gauze pavilion, the cloak, and the silk handkerchief.

We are not satisfied either with the assertions made concerning these modes of protection, or with the explanations above given. We would refer again to the doctrine so often dwelt upon of the necessity of a combination of moisture with Malaria to enable it to act. A wall presents a mechanical obstacle to a current of air, impregnated with Malaria, which, if it carries a dense fog, will not easily raise it over a wall of considerable height, without much dispersion, and of course much diminution of intensity. Dense, moist air will not pass through a sufficiently thick canvass or tent cloth, which will hence afford a certain degree of protection. The sides of a lofty mountain, the foliage of a forest attract and condense the moisture, which, mingled with the air, gives wings and intensity to pestiferous effluvia. We do not believe in the efficacy of a gauze pavilion, which is by no means close enough to offer an obstacle to the entrance of any form of moisture; nor of the silk handkerchief held to the mouth, a measure, the suggestion of which, a late writer conceives to promise as much general utility, and to merit as much honour as Davy's discovery of the safety lampsimply, because we do not consider the mouth and interior surfaces to be the only inlet of this poison, which is as capable of exerting its deleterious influence upon the skin as elsewhere.— Fires kept burning in an apartment, have a tendency to keep the air, within that apartment, warm and dry-that is, by raising its temperature, it increases its power of dissolving moisture; it is clear that a current of cooler and moist air being admitted into such a chamber, will, by the immediate solution of the moisture which it contains, precipitate the Malaria now left unsupported by its former ally, in an inert, dry form; or if the affinity be too tenacious to be thus destroyed, its concentration must be inevitably lessened in a material degree. It is thus we account for the immunity of the charcoal burner of De Lisle, and of others

under similar circumstances, and, for the reputation of protective power, enjoyed by venetian blinds and gauze pavilions.

We do not think that enough stress has been laid upon the efficacy of trees, in giving protection from the influences of Malaria. It is true, that their usefulness has been acknowledged from the earliest times. We might fill pages with trite quotations from Pliny, Varro, Lancisi, Volney, Rush, Johnson, and others, to establish this point which has never been disputed. But we are anxious to contend for an important distinction here. Every kind of tree will offer a mechanical impediment to the passage of air carrying Malaria; any foliage will condense the moisture with which it is combined; but if this were all, then should the densest growth, and the broadest and thickest foliage be of most obvious efficacy in prevention. The contrary, however, is remarkable and notorious. The pine, who, with his tall trunk, elevated branches and linear leaves, opposes less mechanical difficulty to the transmission of air, and less surface for the concentration of dews and vapours than any other of the majestic inhabitants of the forest, seems gifted with singularly salubrious powers, and imbued with healing and preserving virtue in every bough. To what shall we attribute this. Every tree circulates its peculiar fluids; that the effluvia which it secretes and eliminates, are also specific and peculiar, is equally evident; it is not altogether unreasonable to suppose that certain of these exhalations may possess chemical properties and affinities that enable them to combine with and decompose, or neutralize Malaria, or the principles which go to constitute this poison. Whether all other trees, whose juices are of a terebinthinate quality, are endued with similar efficacy with the pine, we are not prepared to say, but we believe that observation will go far to establish the fact.

We are now prepared to indicate the various modes by which we are to endeavour, at the diminution of the production of Malaria in the first instance, and, in the second, at the contraction of its limit of injurious operation. A judicious system of draining, if carried into energetic operation, is capable of entirely relieving our middle and upper country from the invasion of Malaria disease. In our low country, although it does not promise so much, at least, immediately, it is still our most important, nay, almost our only means of hopeful relief. The draining of low, moist lands has been always found to improve the air around them, ultimately, though at first, as in early clearing, by increasing the exposure of the decaying material formerly overflowed with water, it increases, sometimes, in a terrible degree, the amount of miasmata evolved. The enterprise of our

sister city Savannah, has instituted, on a large scale, an experiment of the effect of draining, and the system of dry culture, applied to the rice-lands in her vicinity, is said to be already productive of beneficial results. The probabilities in its favour are every day, for reasons above alluded to, becoming greater and greater. Every inhabitant of the south must pray heartily for its entire success.

Our soil is composed, to an inexhaustible depth, of vegetable materials; the heat of our climate will remain the same, or nearly the same forever; if we cannot convey off the moisture so as to diminish, very considerably, the decomposition which it fosters, and the evaporation which gives force to the product of that decomposition, this fertile portion of our globe must, forever, continue to be, to the same extent, as at present, uninhabitable, or be abandoned to the lower orders of the animal creation. Nor should we be discouraged by the apparent vastness of the undertaking. By means, such as these, many large portions of country have been reclaimed and improved, and have been found, richly, to repay the labour expended on them.

Houses, in a Malaria country, should be situated on such elevations as may present themselves, somewhat raised from the ground, on the western side of a water-course or swamp, if there be one in the neighbourhood. Until the draining of this swamp is effectually accomplished, the exuberant underwood and small bushes which line its banks should be left undisturbed. A considerable body of trees, completely cleared of underbrush, should surround the house at a little distance from it. Pines should be left standing, or a situation near them chosen-if they are not at hand, we think there is some reason to believe the hickory to be next in value, as a protective from, or corrective of, Malaria. During the summer and autumn, fires should be lighted at evening, and kept burning, until an hour after sunrise in the morning, especially if the weather be close and damp, or if fogs rise from the ground, or approach the house from any quarter.

It is to the several circumstances, formerly noted, which limit the sphere of action of Malaria, its necessary combination with aqueous vapours; its consequent weight which prevents it from rising in a state of concentration to any great height, and obstructs its passage to a distance, unless when wafted by winds, which, at the same time, dilute and disperse it, and the attraction and affinities which cause it to adhere to trees, and occasion it to be more or less acted on by the emanations from them, it is to these circumstances that we must attribute the salubrity of our pine-land settlements, their comparative-nay, with regard to

some of them, we might venture to say absolute exemption from the dominion of Malaria, and the happy protection which they afford from miasmatic diseases. Situated as they are in the very heart of our low country, surrounded by and in the midst of fields and morasses, their existence is of the utmost importance to the agricultural part of our population. Shaded by the lofty pine, fixed on a soil, light, arid and absorbent, and unincumbered by low thick masses of underwood, we have here the favourable conditions of dryness, a certain degree of elevation-these tracts being well entitled to their common appellation of "ridges"-sufficient ventilation-free admission being given to the sun and to breezes from whatever direction-the presence of trees, and these of a genus whose terebinthinate exhalations are almost universally believed to distribute some principles of a balmy and salutary nature.

To preserve these advantages, however, in their full value, some attention would seem to be necessary. The most perfect cleanliness of yards and offices must be observed; nothing should be planted near the dwellings, even the delights of the flower garden being prohibited, and all offal, of every kind, buried at some distance. It has been recommended also, that a new position should, every four or five years at farthest, be selected for the house, which ought as often to be rebuilt of new materials. Certain of our pine-land villages have, however, subsisted for a long series of years, and still retain their reputation as healthy residences. We are not prepared to say whether these derive their established character for salubrity, from the observance of the regulations pointed out, or from some felicitous peculiarity of location, which prohibits the invasion of noxious effluvia.

It has been noticed, that the presence of moss (Tillandsia usneoides) upon the pine, is an indication of a state of the air at the spot, unfavourable to health, and that the gradual encroachment of this parasitic vegetable upon the trees of a ridge, previously healthy, is a fair warning that it is about to lose this general, though not uniformly characteristic exemption of our sandy barrens. We shall not find it difficult to explain the fact, allowing its correctness. The moss delights in moisture, and attaches itself to the growth of moist situations. It forms thus a good hygrometer, and gives proof that the neighbouring low grounds are becoming more abundant, and spreading more widely than formerly. We might hope to avert the threatened evil by timely and perfect draining, and it is to be lamented, that such attempts have not been more frequently and energetically made, VOL. II.-No. 3. 24