rather than yield, as we have too often done, point after point, to the pestiferous dominion of this evil principle. In a similar way would we account for the great abundance of insects and vermin to be found in miasmatic situations, and for the common opinion that an unusual multiplication of gnats, flies, musquitoes, &c. betoken the approach of an unhealthy season. These little creatures cannot exist without moisture, which, with heat, so much fosters their production, that these principles have been supposed by not a few philosophers, fully capable of generating them or bringing them into being.

Dr. MacCulloch goes at some length into the discussion of the question why Rome suffers more from Malaria now, than she did formerly. Without entering into the details of this matter we like the suggestion, (p. 175) that "after all, one of the greatest differences between Ancient and Modern Rome may be rather a political than a physical question; the difference between a state of activity and wealth despising disease, and one of sloth and poverty retiring before it, giving it also the means of acting with an accelerating effect." This is, indeed, a brief expression of our views. There are abundant allusions made in the older writers, which prove that Rome and its surrounding country were always specially liable to pestilential fevers; if, in a greater degree now, the political changes to which she has been subjected, are entirely sufficient to account for all and more than all the difference.*

*There is one circumstance connected with the different state of population in the vicinity of Rome, in ancient and modern times, which we think has not been sufficiently considered. The experience of Carolina proves, that a dense population, although the cause of some diseases, yet corrects and diminishes the sources of others. This is found to be the case in the centre of Rome as well as of Charleston. The very smoke produced by the domestic uses and the necessary manufactures of a numerous people, diminishes and almost destroys those remittent and intermittent fevers which are the common forms of disease in an unhealthful country. Under such a protection, mankind will multiply and increase, until some political revolution shall change the condition of the population. Until war shall decimate the inhabitants with the sword-scatter abroad those who escape, or reduce them to abject poverty. The causes of depopulation will then begin to act, and will increase with accelerated energy. Diseases will re-appear and multiply. Those who can fly will shun the pestilence, those who remain will, in a great measure, perish every circumstance will give new activity to this destroying power, until a country becomes as desolate and dangerous as the Campagna of Rome. The difficulty in the case is, to fill such a country with inhabitants. Now it should be kept in remembrance, that in the prosperous days of Rome, the plains of Latium and Etruria, improved and embellished by the arts and wealth of a prostrate world, were cultivated by slaves, whose residence was not voluntary. These, the wars and conquests of Rome supplied in unstinted numbers. The captives and victims of each war were distributed among the conquering soldiers, or sold in the markets of the capital. A numerous population was thus constantly maintained in all the districts adjacent to Rome. The country was, probably, made more healthful by this population, and the wealthy proprietors resided on their domains only in those months, when the Malaria did not manifest itself. Cicero and Horace

The subject is particularly interesting to us from a certain analogy presented in the history of the lower division of our own section of country. Throughout the summer and autumn, our flourishing plantations and ripening fields must be abandoned to the care of slaves and hirelings, and our planters confined closely to the sea-coast, or imprisoned in the settlements among the pine-lands; and although our rich low grounds and woody swamps must always have been the local habitation of every miasmatic affection, yet there is a general belief prevalent, that this evil has for some time past been increasing. During the reign of frost, the inhabitants of the low country think themselves safe from the ravages of miasmatic pestilence. Released from their summer residences in the month of November, they may remain among their fields until the return of spring, whose balmy zephyrs waft to us on their soft warm wings the elements of destruction. It is too certain that the necessity for this enforced absence urges somewhat earlier than in former years. The trim avenues, and well-built mansions, scattered over the face of these fertile districts by the successive generations of our predecessors, may be seen, in numerous instances, fast hastening to decay-the period of safe residence in them being, as it is alleged, sensibly diminished and still diminishing.

It is not easy to give a satisfactory explanation of a statement so melancholy, yet we will notice some circumstances which seem to us to claim attention as affording a hint which may lead to a solution of these difficulties. We have spoken of the absolute necessity of the presence of certain degrees of heat to produce Malaria; paradoxical as it may appear, it yet derives its greatest occasional power from cold. Malaria diseases are most rife and most malignant in September and October, when the nights are cool and the dews settle upon the earth at evening, and the fogs rise heavy and dark in the morning; the alter

speak frequently of the custom of retiring, to avoid autumnal fogs and fevers, from Rome itself to the delightful villas amidst the ridges of the Appenines or to the sea coast of Baiæ and Salernum. And with regard to the cultivators of this soil, we suspect that as now in similar cases, as even in countries where free labourers are employed in mines, in crowded manufactures, in the workshops and occupations in which lead, copper, arsenic, sulphur and many other poisonous substances are freely used, the calculations were made as to the profit or convenience, not the healthfulness of the employment. How little the Romans regarded the insalubrity of a climate, or permitted it to interfere with their arrangements, an incident mentioned by Tacitus, will distinctly shew. The Senate, wishing during the reign of Tiberius, to remove from Rome the followers of Egyptian and Jewish rites, decreed, "ut quatuor millia libertini generis, ea superstitione infecta, quis idonea ætas, in insulam Sardiniam veherentur, coercendis illic latrociniis, et si ob gravitatem coeli interissent, vile damnum."-An. Lib. ii. 85. This will also shew that the climate of Sardinia cannot be now worse than it was reputed to be in the days of Tiberius or of Tacitus.

nations of temperature. not only aiding in this way the concentration of the effluvia with moisture, but affecting the constitution by their agitating concussions, and debilitating the frame by the alternate excitement and languor which must end in more or less notable prostration. We would thus also account for the fact, long recorded among planters, that attacks of country-fever are more likely to occur in May than in June, whence many of them have derived the habit of remaining on their plantations until the latter month, changes of place being supposed, whether justly or not we do not pretend to determine, to give additional susceptibility. Warm as is our vernal sun, the nights of May are often cool and refreshing. The winds during that month blow not unfrequently from the eastward, and their chilling impulse is imagined to have a tendency to give effect to the poison which is lurking in the frame of him who has been breathing the contaminated air of his country residence. The difference at this season is, of course, not so open or obvious, as that which exists between midsummer and the late autumnal months, but it is not unknown nor has it passed unobserved. We need hardly remark that the power of Malaria is but feebly developed in early spring, when the frost has not ceased to retard the processes of vegetable decay, and to confine to the earth, at the most dangerous period-night-the moisture which gives activity to the poison. But it is in confirmation of the views stated above, that if in the autumn an early frost occasioned by a premature and hasty north wind, with previous rain, has seduced the inhabitants of our lower country into the Malaria districts, the fevers to which they thus become liable, are particularly severe, obstinate and malignant. We believe that such irregular alternations of temperature, have been more frequent of late, than they were formerly, both in spring and autumn.

But this direct and immediate effect of cold is not all, nor is it, perhaps, even the most important of its agencies in the matter under consideration. The permanent influence of cold upon the human system cannot be exactly described; we call it tonic, constringent, roborant. That of heat is probably directly opposite. Very different then will be the states of the constitution which result from exposure to these two conditions of temperature; very different the predispositions to disease built up in the constitutions so modified. One who has become familiar with the influences of heat, having gone through a regularly progressive series of effects producible by it, directly and indirectly, in warm climates, is said in common language, to be assimilated to such climates; he has become less liable, generally speaking, to their endemic diseases, than

he was originally. Impressions thus made on the constitution, may, however, be erased; assimilation thus acquired may be absolutely lost by a return to colder regions, and a longer or shorter absence from the scene of the first mentioned changes. The contrasted operation of cold may be undergone, and the susceptibility renewed, which had been impaired or lost. It has been usual with our southern people in reasoning upon this principle, for it is universally recognised and acted on, to regard, as somewhat dangerous to a young native, whose constitution is still plastic and liable to impressions, or to a stranger who has been resident here, the prolonged absence of a summer in a northern region. Now, although we would by no means go so far as to deny the possible influence of a Northern or European summer, for we have more than once had personal occasion to notice it, yet we look upon a winter spent in those climates, as much more impressive in changing the state of a southern or assimilated constitution, than many summers, for the plain reason, that the difference between the warmth of our summers and those of northern countries, even so far as Russia, is infinitely less than the difference between our winters and theirs in severity of cold. It is uncommon in Charleston to see a crust of ice covering a pail of water, which will endure the heat of a single day; at Philadelphia, the great river Delaware is frozen over annually, so as to bear on its surface sleighs and carts, and immense multitudes of people. But it is far from being a rare occurrence, that the extreme summer height of the thermometer in Philadelphia, we might venture to say in Canada, equals its highest range in Charleston. Let us suppose then, that instead of our going abroad to suffer a northern winter, which can happen at once to but few comparatively, a northern winter should come upon us at home. The effect would evidently be the same in both cases precisely-the constitution would lose in a greater or less degree, the protection afforded to it by its previous assimilation, and we should have become to a corresponding extent, strangers. Facts will be found to confirm these views. For instance, our memorable epidemic summer of 1827, found us all, in some measure, strangers, the winter then just past, having been unprecedentedly cold; and the fevers of that spring, though a dry one, and not particularly hot, commenced earlier and with more violence than had ever before been known. Our last winter was, on the contrary, but a genial and mild autumnal season, fruits having ripened during each month even in the open air. Our spring and commencing summer has scarcely shown a case of fever; the very few that have occurred, have been exceedingly mild, and our community has not as yet to

deplore a single member lost in this manner.

What other in

fluences may hereafter operate to change the character of our remaining warm months, it would require the spirit of prophecy to point out, yet we are sure of having this in our favour, that we enter upon them with all the callousness which the repetition of impressions can bestow.

We believe further, that it would not be difficult to make good the assertion, that irregularities of temperature have been particularly remarkable within a few years, not only in the southern section of our Union, but over the whole Atlantic coast, and, perhaps, over all the civilized world. For proof of this, we would refer to the steady summer warmth of the winter of 1827-28, both with us and in the northern and middle states, vegetation being scarcely more than checked or retarded, and that, we believe, rather by the habits of plants, to follow the revolutions of the year, than by the absolute influence of cold; to the extreme cold of the preceding winter (1826-27) in these southern regions; to the unheard of rise of the thermometer in the summer of 1826, to 90° of Farenheit, in London and Paris; to a similar extraordinary degree of heat in 1825, in the northern parts of our continent, we, ourselves, having noticed it at 97° in June of that year, at the foot of the Green Mountains of Vermont; and to the heat of 1824, along our sea-coast, and in some interior districts where the thermometer reached 103 and 104°. We need surely adduce no other evidence than this, to prove that some very extensive agencies have been at work to influence of late the regular increments and decrements of the temperature of seasons; and such causes would, according to the opinions we have been advocating, be sufficient to account, in a great part, for the alleged anticipation of the season of Malaria fevers with us. Setting aside all this, however, we should still be able to explain the apparently increased insalubrity of portions of our own country. Partial clearing, by exposing virgin soil; by taking away the shade of trees, and thus admitting the heat of the sun; by the mere removal of the trees themselves; by laying bare the edges and banks of our numerous bays, ponds and swamps, whose margins are naturally sheltered by a thick vegetable fringe-this very line of margin being, on account of the fluctuating quantity of water present, the portion of it most productive of Malaria-partial ditching, by collecting water to stagnate, without conveying it off readily, rapidly and entirely; partial draining, by uncovering in greater or less degree, the foul, fermenting beds of the bays, pools and swamps above-mentioned; partial cultivation, by continually turning up new lands, and leaving the old to produce rank grass