A very few years ago it was the general opinion, even of the best informed, that epidemic diseases originate in atmospheric influences over which man has no control. A reservation seems, however, to have been made in respect of the Oriental, or as some term it, the African, plague, a malady the most frightful to which man is liable. Writers of the highest order traced to a damp, hot, and stagnating air, generated from the putrefaction of animal substances, and especially from the swarms of locusts, not less destructive to mankind in their death than in their lives, the fatal disease which depopulated the earth in the time of Justinian and his successors. The disease was reported to have first appeared in the neighbourhood of Pelusium, between the Serbonian bog and the eastern channel of the Nile. Thence tracing a double path it spread to the east, over Syria, Persia, and India, and penetrated to the west, along the coast of Africa, and thence to the continent of Europe. But in order to explain how it spread, it was necessary to invent another theory and add it to the first; the disease once generated, was said to spread by contagion. It is related in “The Decline and Fall of the Roman Empire,”11 that in the spring of the second year (after its first appearance), Constantinople, during three or four months, was visited by the pestilence. It did not reach the capital of the empire at once, but travelled slowly and irregularly, after the manner of modern cholera. In the admirable descriptions of the immortal historian, we can trace all the symptoms of the true Oriental plague, identical in its phenomena and effects with the sufficiently numerous visitations which have since occurred, and with that no doubt which, lately originating at Bengazzi, and spreading to Tripoli, once more threatens the European family of nations. In a damp, hot, stagnating air, observes the historian, who in his account follows Procopius, this African fever is generated from the putrefaction of animal substances, and especially from the swarms of locusts, “not less destructive to mankind in their death than in their lives.” But the ferment and putrefaction thus created scarcely accounts for the origin of the disease, and its extension north-wards into the coldest regions of Europe is inexplicable on such a hypothesis, though aided by the modern hypothesis that its propagation is due simply to the neglect of sanitary regulations, a theory now happily extended to all zymotic diseases. Passing over the question as to the contagious nature of plague, typhus, cholera, scarlatina, measles, a question still undecided, and adhering simply to facts, we are assured by Procopius, the fidelity of whose descriptions the great historian seems disposed to vouch for, that the disease always spread “from the sea coast to the inland country; the most sequestered islands and mountains were successively visited; the places which had escaped the fury of its first passage were alone exposed to the contagion of the ensuing year. The winds might diffuse that subtle venom; but unless the atmosphere be previously disposed for its reception, the plague would soon expire in the cold and temperate climates of the earth. Such was the universal corruption of the air, that the pestilence which burst forth in the fifteenth of Justinian, was not checked or alleviated by any difference of the seasons. In time, its first malignity was abated and dispersed; the disease alternately languished and revived; but it was not till the end of a calamitous period of fifty-two years that mankind recovered their health, or the air resumed its pure and salubrious quality. No facts have been preserved to sustain an account, or even a conjecture, of the numbers that perished in this extraordinary mortality. I only find that during three months, five, and at length ten thousand persons died each day in Constantinople; that many cities of the East were left vacant, and that in several districts of Italy the harvest and the vintage withered on the ground. The triple scourge of war, pestilence, and famine afflicted the subjects of Justinian; and his reign is disgraced by a visible decrease of the human species, which has never been repaired, in some of the fairest countries of the globe.” The plague of the time of Justinian is known to us only through the medium of the Greek and Roman writers. We know nothing as to how it affected the remote East, or whether that portion of the earth escaped. No record exists to prove or disprove the passage across the Atlantic, in ancient times, of plagues and pestilences, such as we know now overleap with ease that seemingly impassable barrier. The history of cholera in its progress from the East, though drawn up by skilful official writers, tells us as little of its real nature as Procopius did of the plague. It resembles in some respects the history of ancient Egypt, each discovery merely adding another enigma to the already existing and unexplained. Its propagation by contagion is still denied by the first of medical authorities, and yet it must be admitted that it pursues in a mysterious manner the paths of commerce, as if by the abuse of trade, plagues, which would otherwise become extinct in the land of their origin, are diffused over the continents of the world.12
The propagation of the plague by contagion was, as we have already seen, distinctly denied by Procopius, and in this opinion he seems, as in modern times, to have been backed by a majority of the people. The immortal historian of “The Decline and Fall” did not partake of Procopius’ doubts. “Contagion,” he remarks, “is the inseparable symptom of the plague, which, by mutual respiration, is transfused from the infected persons to the lungs and stomach of those who approach them. While the philosophers believe and tremble, it is singular that the existence of a real danger should have been denied by a people most prone to vain and imaginary terrors. Yet the fellow-citizens of Procopius were satisfied, by some short and partial experience, that the infection could not be gained by the closest conversation; and this persuasion might support the assiduity of friends or physicians in the care of the sick, whom inhuman prudence would have condemned to solitude and despair. But the fatal security, like the predestination of the Turks, must have aided the progress of the contagion; and those salutary precautions to which Europe is indebted for her safety, were unknown to the government of Justinian. No restraints were imposed on the free and frequent intercourse of the Roman provinces. From Persia to France the nations were mingled and infected by wars and emigration, and the pestilential odour which lurks for years in a bale of cotton was imported by the abuse of trade into the most distant regions.”13
Thus has been bandied about from the earliest times to the present day, the great question of the origin of the pestilential diseases, and their contagious properties when once produced. The question still remains unsettled, nor has the advent of the cholera in modern times contributed in the slightest degree to bring the disputation to a demonstrative issue.
Are they of terrestrial or atmospheric origin properly, or do both contribute their share towards the production of pestilences? How originated the cholera, and how does it spread? These questions may still be asked, and when asked must remain unanswered. The share ascribed to man in the production and propagation of this and similar diseases is mainly the object of this inquiry, and to that I shall adhere as much as possible.
Men, ever anxious to discover the causes of events, ascribed the origin of the plague in the reign of Justinian to the putrefaction of locusts; but the same event may and has happened without being productive of similar results—without, indeed, causing any disease whatever, as if the poison, though present, were ineffectual unless aided by other circumstances at present unknown to man. Those who have seen cholera only as it prevails on the rotten banks of the Ganges, ascribe its origin to heat and putrefaction, its extension to the habits of a densely-congregated people. They forget, or choose not to remember, that it raged in the depth of winter in the cold regions of Russia and of Scotland, in thinly-populated villages, in hamlets, and insulated cottages, scattered over the elevated yet cultivated estates of noble and wealthy proprietors.14 Those who have studied the phenomena of typhus only in the horrid slums of Glasgow, in the wynds and closes of cold and bleak Edinburgh—from which it is never absent, occasionally raging with something like the virulence of a plague—ascribe the origin and extension of the disease to cold and hunger, to a deficiency of animal food, and to a contempt for all sanitary arrangements; but they do not choose to remember that a few years ago typhus in its worst form appeared in the south-eastern angle of England, spreading thence through the midland counties, deeply affecting the population of hamlets and villages the salubrity of whose site was unquestioned. And if negative evidence be held sufficient to refute Procopius’ theory of the origin of the true plague, we have but to look into the pages of a modern traveller, whose official position naturally adds to the value of his testimony. Mr. Barrow, in describing a visitation of locusts to the Cape of Good Hope, makes the following curious remark:—“Their last departure was rather singular. All the full-grown insects were driven into the sea by a tempestuous north-west wind, and were afterwards cast upon the beach, where it is said they formed a bank of three or four feet high, which extended from the mouth of the Bosjesman river to that of the Becca, a distance of nearly fifty English miles; and it is asserted that when this mass became putrid, and the wind was at south-east, the stench was sensibly felt in several parts of the Sneuwberg.” The distance over which the stench was felt must have been at least a hundred miles, the range of the Sneuwbergen being at about this distance from the coast.
It is hardly necessary for me to observe, that no disease followed the destruction and putrefaction of these locusts. The colony of South Africa still continues free from plague and cholera, and many other diseases afflicting the most favoured of European lands; consumption, scrofula, and fever are all but unknown. I am not aware that the inhabitants are in any way remarkable for their sanitary arrangements, whilst of the Hottentots it may with truth be said, that they are at once the healthiest and dirtiest people in the world.
Thus, after the lapse of many centuries, the great questions debated in the time of Justinian—may we not rather say in the days of Thucydides?—surge up again whenever a new plague appears on the earth. The professors of “the conjectural art,” anxious to vindicate their claim to activity, and to share in the laudations bestowed on the superior intelligence of the present day, offer at present a highly consolatory view, not only as to the origin of these diseases, but as to their speedy suppression. They argue that, but for the neglect of hygienic measures, such influences or poisons would either not arise, or would pass on their course, leaving the nations unscathed. In the meantime, it is prudent to recall to the recollection of those who arrive rashly at conclusions such as these—who theorize on narrow local ground—who are sanguine enough to look forward to the speedy extinction of all zymotic diseases, that pestilential and destructive epidemics are not confined to man; that, under the form of murrains, they destroy the beasts of the field. In the murrain of 1747, it is stated on authority that 30,000 cattle died in Cheshire in the course of half a year. The marsh districts suffered most; and it has even been conjectured that such epizootic diseases usually originate amidst swamps and malarious districts; but of this we have no proofs. Even the harvests to which man looks for sustenance are not spared—nor the vine; the life-destroying principle, attacking these lower forms of life, cannot well be traced to the neglect of hygienic measures on the part of man, or of the animals or plants themselves; and yet in the midst of these bogs and marshes which undeniably give origin to some forms of fever, the buffalo, the ox, the camel, the elephant, and the wild of all species, live and thrive. Thus the question of the origin of disease is complicated ab origine; the origin of typhus—that scourge and pest of the nations inhabiting the temperate regions, more especially of Western Europe, and of the British Isles in particular—is absolutely unknown. To affect to trace it to a foul drain, an uncleansed sewer, an untrapped cesspool, a laystall, a collection of neglected rubbish, is clearly against the evidence and the daily experience of thousands; but all are agreed that in certain fenny and marshy countries fevers prevail—intermittent in temperate, remittent in ardent climes nearer the tropic; whilst within the tropics the life of the European stranger can scarcely be valued at a week’s purchase.15 To this destructive influence, most commonly connected with a marshy soil, the Italian first gave the name of malaria—a useful appellation, universally accepted as implying no theory; and had such fevers been found only in such localities, the inference must have followed, that a something, open to the chemist to discover, emanating or produced by these marshes, was solely and distinctly the cause of all such fevers. But now a more careful and extended inquiry shows that such fevers are not confined to those districts, but infest even the hay-field, are not unfrequent in or near woods growing on soils where marshes have ever been unknown; whilst as regards the more ardent remittents of Eastern countries, the statistics of Major Tulloch have all but destroyed the theory which would trace to marshes exclusively the fevers which in such countries set all medical treatment and all human precautions at defiance.16
This uncertainty of life from the effects of malaria must ever, I think, remain whilst the true nature of the poison is unknown; and it is with a view to discover, if possible, the circumstances under which it originates, that I undertook this difficult inquiry. Long resident in a country supposed to be an ague-producing land, I watched with much interest the social condition of a sagacious, prudent, and industrious race of men, who could thus, at one and the same time, preserve their liberty and life from the hostile assaults of furious, implacable tyrants from without, and of an insidious, invisible enemy within, walking stealthily around the habitations of men, poisoning the air of his house, his fields, and gardens. It was in Holland that a French general, writing to the great Napoleon, and complaining of the destruction of the garrisons by fever, received from him the only reply which at the time the necessities of the mighty conqueror permitted him to give—“L’homme meurt partout.” “Man dies everywhere,” was the only answer, if answer it could be called, to a kind-hearted commander, more touched by the calamity around him than by the exigencies of the State.
But how was it that whilst French and English soldiers perished so unaccountably in the prime of life, the inhabitants of these countries lived seemingly unaware of the pestilence walking around and amongst them? This problem may, I think, be solved; and as not foreign to the matter in hand, I may be permitted to glance at the character, position, and social condition of a race and a nation so distinct from all other branches of the great European family. My remarks will bear mainly on the influence they exercise over the portion of the earth they inhabit, and on the modifications which man’s industry, guided by prudence and science, may imprint on “the earth, the air, and water” of the territory which, under the circumstances I now describe, may especially be called their own.