In treating of the diseases of Africa, the same author takes notice of those of Egypt; which country, he says, is rendered unwholesome by the annual inundation of the Nile, and being surrounded on three sides by large and extensive deserts of sand, by which means it is exposed to the effects of that noisome vapour, which, during the summer months, arises from sultry, hot sand. He doth not, however, say, that the true plague originates in this country, either from the inundation of the Nile or any other cause. On the climate of Egypt I shall once more quote M. Savary, who is a strenuous advocate for its healthiness, and is at pains to confute the opinion of Mr. Pauw, and others, who assert the contrary. “Mr. Pauw (says he) pretends, that at present Egypt is become, by the negligence of the Turks and Arabs, the cradle of the pestilence; that another epidemical disease, equally dreadful, appears here, by the caravans of Nubia; that the culture of rice engenders numerous maladies; that the want of rain and thunder occasions the air of the Thebais to acquire a violence that ferments the humours of the human body, &c.” “These assertions (M. Savary observes) have an air of probability, which might impose on people who have not lived in Egypt; but Mr. Pauw has ventured opinions in his closet, without the guidance of experience. In vallies, indeed, enclosed by high mountains, where the atmosphere is not continually renewed by a current of air, the culture of rice is unwholesome, but not so, near Damietta and Rosetta. The plains are nearly on a level with the sea; neither hill nor height impedes the refreshing breath of the north, which drives the clouds and exhalations off the flooded fields southwards, continually purifies the atmosphere, and preserves the health of the people; so that the husbandmen who cultivate the rice are not more subject to diseases than those who do not. The heats of the Thebais certainly surpass those of many countries under the equator. Reaumer’s thermometer, when the burning breath of the south is felt, sometimes rises to thirty-eight degrees above the freezing point,[27] often to thirty-six. Were heat the principle of diseases, the Said (Upper Egypt) would not be habitable; but it only seems to occasion a burning fever, to which the inhabitants are subject; and which they cure by regimen, drinking much water, and bathing in the river: in other respects they are strong and healthy. Old men are numerous, and many ride on horseback at eighty. The food they eat in the hot season contributes much to the preservation of their health; it is chiefly vegetables, pulse and milk. In Lower Egypt, the neighbourhood of the sea, the large lakes, and the abundance of the waters, moderate the sun’s heat, and preserve a delightful temperature. Strabo and Diodorus Siculus, who long lived here, did not think the country unhealthy. There is, indeed, an unwholesome season in Egypt. From February till the end of May, the south winds blow at intervals, and load the atmosphere with a subtile dust, which makes breathing difficult, and drive before them pernicious exhalations. Sometimes the heat becomes insupportable, and the thermometer suddenly rises twelve degrees. The inhabitants call this season Khamsin, fifty; because these winds are most felt between Easter and Whitsuntide; during which season they eat rice, vegetables, fresh fish and fruit; bathing frequently, and using plenty of perfumes and lemon juice; with which regimen they prevent the dangerous effects of the Khamsin. But it must not be supposed that this wind, which corrupts meat in a few hours, blows fifty days. Egypt would become a desert. It seldom blows three days together; and sometimes is only an impetuous whirlwind, which rapidly passes, and injures only the traveller overtaken in the deserts. When at Alexandria a tempest of this kind suddenly arose, driving before it torrents of burning sand, the serenity of the sky disappeared, a thick veil obscured the heavens, and the sun became blood-coloured. The dust penetrated even the chambers, and burnt the face and eyes. In four hours the tempest ceased, and the clearness of the day appeared. Some wretches in the deserts were suffocated, and several I saw brought to appearance dead; some of whom, by bathing in cold water, were restored to life.”
The internal parts of the continent of Africa are but little known. The northern parts, containing the States of Barbary, are sufficiently healthy; the middle parts of the western coast, known by the names of Negro-land, Guinea, &c. are extremely unhealthy and pernicious to strangers. Dr. Lind informs us, that, at a distance, this country appears in most places flat, covered with low, suspended clouds; and on a nearer approach heavy dews fall in the night time; the land being every morning and evening wrapped up in a fog. The ground is clothed with a pleasant and perpetual verdure, but altogether uncultivated, excepting a few spots, which are generally surrounded with forests or thickets of trees, impenetrable to refreshing breezes, and fit only for the resort of wild beasts. The banks of the rivers and rivulets are overgrown with bushes and weeds, continually covered with slime, which sends forth an intolerable stench. All places however are not equally unhealthy; nor is any place equally unwholesome at all times of the year. It is only with the rainy season that the sickness commences. But as it would be tedious, and not answer our present purpose, to enumerate those places which are healthy, and those which are not, I shall only extract from Dr. Lind’s work an account of one which seems to be as bad as can well be imagined. It is called Catchou, a town belonging to the Portuguese, and situated in 12 degrees N. lat. “I believe (says the author of this account) there is scarce to be found on the whole face of the earth a more unhealthy country than this during the rainy season. We were thirty miles distant from the sea, in a country altogether uncultivated, overflowed with water, surrounded with thick, impenetrable woods, and overrun with slime. The air was vitiated, noisome and thick, insomuch that the lighted torches or candles burnt dim, and seemed ready to be extinguished; even the human voice lost its natural tone. The smell of the ground, and of the houses, was raw and offensive; but the vapour arising from the putrid water in the ditches was much worse. All this, however, seemed tolerable, in respect of the infinite numbers of insects swarming every where, both on the ground and in the air; which, as they seemed to be produced and cherished by the putrefaction of the atmosphere, so they contributed greatly to increase its impurity. The wild bees from the woods, together with millions of ants, overran and destroyed the furniture; while swarms of cock-roaches often darkened the air, and extinguished even the candles in their flight; but the greatest plague was the musquetoes and sand-flies, whose incessant buzz and painful stings were more insupportable than any symptom of the fever. Besides all these, an incredible number of frogs, on the banks of the river, made such a constant and disagreeable croaking, that nothing but being accustomed to such an hideous noise, could permit the enjoyment of natural sleep. In the beginning of October, as the rains abated, the weather became very hot, the woods were covered with abundance of dead frogs, and other vermin, left by the recess of the river; all the mangroves and shrubs were likewise overspread with stinking slime.”
No doubt these accounts are calculated to inspire us with dreadful ideas of the countries mentioned in them. What could be done by the putrefaction of dead animals and vegetables, certainly would be done here; the produce, however, was not the true plague; not even in Catchou; but “a sickness which could not well be characterised by any denomination commonly applied to fevers; it however approached neared to what is called a nervous fever, as the pulse was always low, and the brain and nerves principally affected,” &c. Certainly if in any country heat, moisture and putrefaction could produce a plague, it would be in this. Yet, in all the places we have mentioned, whether India, Arabia, Egypt, or Guinea, (and we might go through the whole world in the same manner) we have not been able to find either moist heat or dry heat, even when aided by putrefaction, insects, and nastiness of all kinds (not justly chargeable upon any climate;) I say, we have not found the united powers of all these able to produce a plague. Nay, it is even doubtful whether climates can produce those inferior diseases above mentioned. Even Dr. Lind, who appears to be so willing to ascribe every thing to climate, seems embarrassed in this respect. “There are many difficulties (says he) which occur in assigning a satisfactory reason, why in some countries, as in those between the tropics, heavy and continual rains should produce sickness; while in other places, especially in the southern parts of Europe, a want of rain for two or three months in summer brings on diseases almost similar. Upon this occasion (adds the Doctor) I cannot help observing, that there is hardly a physical cause which can be assigned for the produce of any disease, that will not admit of some exceptions: thus, not only the woods and morasses in Guinea are tolerably healthy, with some exceptions, in the dry season; but a few instances might be produced of towns surrounded with marshes and a foggy air, where the inhabitants suffer no inconvenience from their situation, even during the rainy season. Do the impetuous torrents of water poured from the clouds during the rainy seasons, in tropical countries, contain what is unfriendly to health? Thus much is certain, that the natives of such countries, especially the mulattoes, avoid being exposed to these rains as much as possible, and when wet with them immediately plunge themselves into salt water, if near it. They generally bathe once a day, but never in the fresh water rivers, when overflown with rains, preferring at such times the water of springs. Is the sickness of these seasons to be ascribed to the intense heat of the then almost vertical sun; which frequently, for an hour or two at noon, dispels the clouds, and with its direct beams instantly changes the refreshing coolness of the air into a heat almost insupportable?
“Further: As the season of those sudden and terrible storms, called the hurricanes, in the East and West Indies, and tornadoes on the coast of Guinea, partly coincides with that of the rains, do these dreadful tempests in any measure contribute to produce the prevailing sickness at those times? It was remarkable one year at Senegal, that, in the beginning of the rainy season, in the night succeeding one of these tornadoes, a great number of the soldiers, and two thirds of the English women, were taken ill, this garrison before having been uncommonly healthy.
“Lastly: Is it not more probable, as in those countries the earth for six or eight months in the year receives no moisture from the heavens but what falls in dews, which every night renew the vegetation, and reinstate the delightful verdure of the grass, that the surface of the ground in many places becomes hard and incrustated with a dry scurf, which pens up the vapours below, until, by the continuance of the rains for some time, this crust is softened, and the vapours set free? That these dews do not penetrate deep into the surface of the earth, is evident from the constant dryness and hardness of such spots of ground, in those countries, as are not covered with grass and other vegetables. Thus the large rivers, in the dry season, being confined within narrow bounds, leave a great part of their channel uncovered, which, having its moisture totally exhaled, becomes a hard, dry crust; but, no sooner the rains fall, than, by degrees, this long parched up crust of earth and clay gradually softens, and the ground, which before had not the least smell, begins to emit a stench, which in four or five weeks becomes exceeding noisome; at which time the season of sickness commences.”
From these quotations it must certainly appear, that the author himself is dissatisfied with his theory; and that, though in the outset he thought heat and moisture, assisted by the exhalations from putrid animal and vegetable substances, sufficient to produce the disorders of which he treats, yet, on a more minute investigation, he is obliged to acknowledge, that something inexplicable still remains. This he now wishes to solve by unknown properties in the water, by confined exhalations, &c. But as the consideration of these things belongs properly to the next section, I shall here only remark, that there hath not yet been given any satisfactory account of the origin of epidemic diseases of what I call the inferior kind, much less of the true plague, which stands above them all, as I have already said, like the serpent Python above other serpents.
To what has been quoted from Dr. Lind, I shall here subjoin the testimony of Dr. Clark, who had an opportunity of observing the epidemic diseases which raged at Bengal in 1768 and 1769. These were, “the remittent fever and dysentery, which begin in August, and continue till November. During the beginning of the epidemic, the fever is attended with extreme malignity and danger; frequently carrying off the patient in twelve hours; and, if not stopped, generally proves fatal on the third or fourth day. In August the remissions are very imperceptible; in October they become more distinct; and, as the cold weather comes on, the fever becomes a regular intermittent. At that time, too, the putrid dysentery begins to rage with the fever. These diseases were very fatal to many Europeans, particularly new comers, in 1768. But in the year 1770, when there was a scarcity of rice, it was computed, that about eighty thousand natives, and one thousand five hundred Europeans, died at Bengal. The streets were covered with funerals; the river floated with dead carcases; and every place exhibited the most melancholy scenes of disease and death. During the sickly seasons at Bengal, the uncertainty of life is so great, that it frequently happens that one may leave a friend at night in perfect health, who shall not survive next day. There have been several instances of persons who have returned home in a state of perfect health from performing the last duties to a deceased friend, and have next day been numbered with the dead. But the cool, agreeable season, from December to March, is productive of no prevailing diseases. The complaints to be met with are in general the consequences, or remains, of the diseases of the former period. The complaints which the Europeans are subject to in the dry months are, the cholera and diarrhœa. Fluxes and fevers are then seldom epidemic; and, when they do happen, are not attended with much danger.
“At Batavia the rainy season is from November to May, during which time malignant, remitting and continued fevers and the dysentery rage with great fatality. Captain Cook, in his first voyage, arrived here in October 1779; the whole crew, excepting Tupia, a native of Otaheite, being in the most perfect health. But, in the course of nine days, they experienced the fatal effects of the climate, and buried seven people at Batavia. On the 3d of December, the ship left the harbour. At that time the number of sick amounted to forty; and the rest of the ship’s company were in a very feeble condition. When the ship anchored at Prince’s Island, in the Straits of Sunda, the sickness increased, and they buried twenty-three persons more in the course of about six weeks. The Grenville Indiaman, which touched at this island in 1771, suffered equally from the malignity of the air. A few were taken on board, when the ship sailed from Batavia, ill of a malignant fever; which spread by contagion at sea, and carried off great numbers. I visited several in this ship, when she arrived at China, who were reduced to mere skeletons, by the duration of the fever and dysentery; both of which were most certainly propagated by contagion.
“Those parts of Sumatra lying immediately under the line are continually subject to rain, and the ground near the shore is low, and covered with thick trees and underwood. The heat being intense, noisome fogs arise, which corrupt the air, and render the country fatal to foreigners. The land of North Island, which lies on this coast, near the beginning of the Straits of Sunda, appears at a distance finely variegated; but at the place where the wood and water are to be got it is low, and covered with impenetrable mangroves, and infested with a variety of insects. It is here that most of the East India ships take in wood for their homeward voyage. A Danish ship, in 1768, anchored in this island, and sent twelve of her hands on shore to fill water; where they only remained two nights. Every one of them was seized with a fever, whereof none recovered: but although the ship went out to sea, none, except the twelve who went on shore, were attacked with the complaint.”
With regard to China, this author says, that the “port of Canton is by no means so healthy as is generally represented. The comparative degree of health which Europeans enjoy here has been ascertained from the instances of the supercargoes, which is, however, a very erroneous standard. The generous and regular way in which these gentlemen live, for the most part, exempts them from diseases; and, being but few in number, no great mortality can take place among them. But seamen, who never observe much regularity in their way of living, who work hard in the day time, are but badly clothed, and not provided against the damps and cold north-easterly winds at night, seldom fail to be afflicted with the diseases already mentioned (fevers and fluxes.) Even the factors of different nations, who reside here for any considerable time, experience all the inconveniences peculiar to any sultry climate: florid health is a stranger to their countenances; their constitutions are soon weakened and enfeebled; and they become subject to habitual fluxes and other complaints, the usual consequences of too great relaxation.”