Of the Plague in general.
CHAP. I.
Of the Origine and Nature of the Plague.
My Design in this Discourse being to propose what Measures I think most proper to defend the Nation against the Plague, and for this End to consider the Nature of Pestilential Contagion as far as is necessary to set forth the Reasonableness of the Precepts I shall lay down; before I proceed to any particular Directions, I shall enquire a little into the Causes, whence the Plague arises, and by what Means the Infection of it is spread.
In the most ancient Times Plagues, like many other Diseases, were looked upon as divine Judgments sent to punish the Wickedness of Mankind: and therefore the only Defence sought after was by Sacrifices and Lustrations to appease the Anger of incensed Heaven.[15]
How much soever may be said to justify Reflexions of this Kind, since we are assured from sacred History, that divine Vengeance has been sometimes executed by Plagues; yet it is certain, that such Speculations pushed too far, were then attended with ill Consequences, by obstructing Inquiries into natural Causes, and encouraging a supine Submission to those Evils: against which the infinitely good and wise Author of Nature has in most Cases provided proper Remedies.
Upon this Account, in After-Ages, when the Profession of Physick came to be founded upon the Knowledge of Nature, Hippocrates strenuously opposed this Opinion, that some particular Sicknesses were Divine, or sent immediately from the Gods; and affirmed, that no Diseases came more from the Gods than others, all coming from them, and yet all owning their proper natural Causes: that the Sun, Cold, and Winds were divine; the Changes of which, and their Influences on human Bodies, were diligently to be considered by a Physician.[16]
Which general Position this great Author of Physick intended to be understood with respect to Plagues as well as other Distempers: How far he had reason herein, will in some measure appear, when we come to search into the Causes of this Disease.
But in order to this Inquiry, it will be convenient, in the first place, to remove an erroneous Opinion some have entertained, that the Plague differs not from a common Fever in any thing besides its greater Violence. Whereas it is very evident, that since the Small-Pox and Measles are allowed to be Distempers distinct in Specie from all others, on account of certain Symptoms peculiar to them; so, for the same reason, it ought to be granted, that the Plague no less differs in Kind from ordinary Fevers: For there are a Set of distinguishing Symptoms as essential to the Pestilence, as the respective Eruptions are to the Small-Pox or Measles; which are indeed (as I have mentioned in the Preface) each of them Plagues of a particular kind.
As the Small-Pox discharges itself by Pustules raised in the Skin; so in the Plague the noxious Humour is thrown out either by Tumors in the Glands, as by a Parotis, Bubo, and the like; or by Carbuncles thrust out upon any part of the Body. And these Eruptions are so specific Marks of this Distemper, that one or other of them is never absent: unless through the extreme Malignity of the Disease, or Weakness of Nature, the Patient sinks, before there is time for any Discharge to be made this way; that Matter, which should otherwise have been cast out by external Tumors, seizing the Viscera, and producing Mortifications in them.
Sometimes indeed it happens, by this means, that these Tumors in the Glands, and Carbuncles, do not appear; just as a bad kind of the Small-Pox in tender Constitutions sometimes proves fatal before the Eruption, by a Diarrhœa, Hæmorrhage, or some such Effect of a prevailing Malignity.
The French Physicians having distinguished the Sick at Marseilles into five Classes, according to the Degrees of the Distemper, observed Bubo’s, and Carbuncles, in all of them, except in those of the first Class, who were so terribly seized, that they died in a few Hours, or at farthest in a Day or two, sinking under the Oppression, Anxiety, and Faintness, into which they were thrown by the first Stroke of the Disease; having Mortifications immediately produced in some of the Viscera, as appeared upon the Dissection of their Bodies[17]. And this Observation of the French Physicians, which agrees with what other Authors have remarked in former Plagues, fully proves, that these Eruptions are so far from being caused solely by the greater Violence of this Disease, than of other Fevers, that they are only absent, when the Distemper is extraordinary fierce; but otherwise they constantly attend it, even when it has proved so mild, that the first Notice, the Patient has had of his Infection, has been the Appearance of such a Tumor: as, besides these French Physicians, other Authors of the best Credit have assured us. From whence we must conclude, that these Eruptions are no less a Specific Mark of this Disease, than those are, by which the Small Pox and Measles are known and distinguished. And as in the first Class of those attacked with the Plague, so likewise in these two Distempers we often find the Patient to dye by the violence of the Fever, before any Eruption of the Pustules can be made.
This Circumstance of the Plague being mortal before any Eruptions appeared, was attended with a great misfortune. The Physicians and Surgeons appointed to examine the dead Bodies, finding none of the distinguishing Marks of the Disease, reported to the Magistrates that it was not the Plague; and persisted in their opinion, till one of them suffered for his Ignorance, and himself, with part of his Family, dyed by the Infection: this Assurance having prevented the necessary Precautions[18].
And this in particular shews us the difference between the true Plague, and those Fevers of extraordinary Malignity, which are the usual Forerunners of it, and are the natural Consequence of that ill State of Air, we shall hereafter prove to attend all Plagues. For since all those Fevers, from which People recover without any Discharge by Tumors in the Glands, or by Carbuncles, want the characteristic Signs, which have been shewn to attend the slightest Cases of the true Plague; we cannot, upon any just Ground, certainly conclude them to be a less Degree only of that Distemper: but as far as appears, they are of a different Nature, are not ordinarily Contagious like the Plague, nor yet have any such necessary relation to it, but that such Fevers do sometimes appear, without being followed by a real Pestilence.
On the other hand, I would not be understood to call every Fever a Plague, which is followed by Eruptions resembling these here mentioned: For as every Boil or Pustule, which breaks out upon the Skin, is not an Indication of the Small Pox, nor every Swelling in the Groin a Venereal Bubo; so there are Carbuncles not Pestilential, and other Fevers, besides the Plague, which have their Crisis by Tumors and Abscesses, and that sometimes even in the Parotid or other Glands. There is indeed usually some difference between these Swellings in the Plague, and in other Fevers, especially in the time of their coming out: for in the Plague they discover themselves sooner than in most other Cases. But the principal difference between these Diseases, is, that the Plague is infectious, the other not; at least not to any considerable Degree.
And this leads me to another Character of this Disease, whereby it is distinguished from ordinary Fevers, which is the Contagion accompanying it. This is a very ancient Observation. Thucydides makes it a part of his Description of the Plague at Athens[19]; and Lucretius, who has almost translated this Description of Thucydides, dwells much upon it[20]. Aristotle makes it one of his[21] Problems, How the Plague infects those who approach to the Sick. And what is of more Consequence, Galen himself is very clear in it[22]; for he has these words: ὅτι συνδιατρίβειν τοῖς λοιμώττουσιν ἐπισφαλὲς, ἀπολαῦσαι γὰρ κίνδυνος, ὥσπερ ψώρας τινὸς, &c. that it is unsafe to be about those, who have the Plague, for fear of catching it, as in the Itch, &c. Indeed this is a thing so evident, that we find it at present the current Opinion of all Mankind, a very few Persons only excepted, who have distinguished themselves by their Singularity in maintaining the opposite Sentiment. And it is something strange that any one should make a Question of a thing so obvious, which is proved sufficiently by one Property only of the Disease, that whenever it seizes one Person in a House, it immediately after attacks the greatest part of the Family. This Effect of the Plague has been so remarkable at all times, that whoever considers it well, cannot possibly, I think, have any Doubt remaining, or require any stronger Argument to convince him, that the Disease is infectious. For this very reason the Small-Pox and Measles are generally allowed to be contagious; because it is observed, that when either of these Diseases is got among a Family, it usually seizes successively the greatest part of that Family, who have not had it before: at least if such in the Family hold free Communication with the Sick. And by the same Argument the Plague must be concluded to be infectious likewise. It cannot be pretended, that this is occasioned in the Plague from this only, that the sound Persons are render’d more than ordinarily obnoxious to the unhealthy Air, or whatever be the common Cause of the Disease, by being put into fear and dispirited, upon seeing others in the same House taken sick: For if this were the Case, Children, who are too young to have any Apprehensions upon this Account, would escape better than others, the contrary of which has been always experienced.
It is true, some have not been attacked by the Disease, though constantly attending about the Sick. But this is no Objection against what is here advanced: for it is as easily understood how some Persons, by a particular Advantage of Constitution, should resist Infection, as how they should constantly breath a noxious Air without hurt. An odd Observation of Diemerbroek deserves notice in this Place; That, part of a Family removed into a Town free from the Plague, was observed by him to be taken ill of it soon after the part left behind in the diseased Town fell sick: which certainly could scarce have happened, unless a Communication between the Healthy and the Sick, by Letters or otherwise, was capable of causing it[23]. Of the same Nature is a Circumstance recorded by Evagrius of the Plague, which he describes, and what, he owns, surprized him very much: That, many of those, who left infected Places, were seized with the Plague in the Towns to which they had retired, while the old Inhabitants of those Towns were free from the Disease[24]. But to multiply Proofs of a thing so evident, is needless; innumerable are at hand, and several will occasionally occur in the following Parts of this Discourse, when we come to speak in particular of the ways, by which this Infection is conveyed about. I shall therefore say no more in this Place, but only, that all the Appearances attending this Disease are very easily explained upon this Principle, and are hardly to be accounted for upon any other. We learn from hence the reason why when the Plague makes its first Appearance in any Place, though the Number of Sick is exceeding small, yet the Disease usually operates upon them in the most violent manner, and is attended with its very worst Symptoms. Now was the Disease produced not by imported Contagion, but from some Cause, which had its Original in the diseased Place, and consequently from a Cause gradually bred, the contrary must happen: the Diseased would at first not only be few in Number, but their Sickness likewise more moderate than afterwards, when the morbific Causes were raised to their greatest Malignity. From the same Principle we see the reason, why People have often remained in Safety in a diseased Town, only by shutting themselves up from all Communication with such, as might be suspected of giving them the Disease. When the Plague was last in England, while it was in the Town of Cambridge, the Colleges remained entirely free by using this Precaution. In the Plague at Rome in the Years 1656 and 1657, the Monasteries and Nunneries, for the most part, defended themselves by the same Means[25]: Whereas at Naples, where the Plague was a little before, these Religious Houses, from their Neglect herein, did not escape so well[26]. Nay the Infection entered none of the Prisons at Rome[27], though the Nastiness of those Places exposes them very much. But, to avoid Prolixity, I shall give only one Instance more. I think it cannot be explained in any other reasonable manner, how the last Plague in the City of London, which broke out in the parish of St. Giles’s in the Fields towards the latter end of the Year 1664, should lie a-sleep from Christmas to the middle of February, and then break out again in the same Parish; and after another long rest till April, shew itself again in the same Place[28].
To proceed: Whoever examines the Histories of Plagues in all times, which have been described with any Exactness, will find very few, that do not agree in these essential Marks, whereby the Plague may be distinguished from other Fevers. I confess an Instance or two may be found to the contrary; perhaps the History of our own Country furnishes the most remarkable of any[29]. But Examples of this kind are so very rare, that I think it must be concluded, that the Plague is usually one and the same Distemper.
In the next place I shall endeavour to shew, that the Plague has always the same Original, and is brought from Africa, the Country which has entail’d upon us two other infectious Distempers, the Small-Pox and Measles. In all Countries indeed Epidemic Diseases extraordinarily mortal, are frequently bred in Goals, Sieges, Camps, &c. which Authors have often in a large Sense called Pestilential: But the true Plague, which is attended with the distinguishing Symptoms before described, and which spreads from Country to Country, I take to be an African Fever bred in Æthiopia or Egypt, and the Infection of it carried by Trade into the other Parts of the World.
It is the Observation of Pliny, that the Pestilence always travels from the Southern Parts of the World to the Western, that is, in his Phrase, into Europe[30]. And the most accurate Accounts in all Times of this Disease, wherever it has raged, bring it from Africa. Thucydides[31], in his admirable Description of the famous Plague of Athens, says, that it began in Upper Æthiopia, then came into Egypt, from whence it was spread first into Persia, and afterwards into Greece.
There is in all ancient History no Account of any Plague so dreadful as that, which broke out at Constantinople in the time of the Emperor Justinian A. D. 543. This is said to have spread its Infection over all the Earth, and to have lasted fifty two Years. The History of it is very well told by Evagrius[32], and yet more learnedly by Procopius[33]: and they both observe, that the Distemper had its Birth in Æthiopia or Egypt.
This is likewise agreeable to the modern Relations of Travellers and Merchants from Turkey, who generally inform us, that the frequent Plagues, which depopulate that Country, are brought thither from the Coast of Africa: insomuch that at Smyrna, and other Ports of that Coast, they often know the very Ship which brings it. And, in these latter Ages, since our Trade with Turkey has been pretty constant, the Plagues in these Parts of Europe have evidently been brought from thence.
The late Plague in France came indisputably from Turkey, as I shall particularly shew in some of the following Pages. The Plague, which broke out at Dantzick in the Year 1709, and spread from thence to Hamburgh, Copenhagen, and other Cities in the North, made its way thither from Constantinople through Poland, &c. And the last Plague in this City, if we may believe Dr. Hodges, had the same Original, being brought to us from Holland, but carried to them by Cotton imported from Turkey[34].
The greatest Mortality that has happen’d in later Ages, was about the middle of the fourteenth Century; when the Plague seized Country after Country for five Years together[35]. In the Year 1346 it raged in Egypt, Turkey, Greece, Syria, and the East-Indies; in 1347 some Ships from the Levant carried it to Sicily, Pisa, Genoa, &c. in 1348 it got into Savoy, Provence, Dauphiny, Catalonia, and Castile, &c. in 1349 it seized England, Scotland, Ireland, and Flanders; and the next Year Germany, Hungary and Denmark: and in all Places, where it came, it made such heavy Destruction, that it is said to have dispeopled the Earth of more than half its Inhabitants[36]. Now since Africa had a share of this Plague in the very beginning, I question not but it had its first Rise in that Country; and not in China, as M. Villani, in his History of those Times, relates from the Report of Genoese Seamen, who came from those Parts, and said it was occasion’d there by a great Ball of Fire, which either burst out of the Earth, or fell down from Heaven[37]. But this Relation is so very incredible, that I cannot think we ought at all to rely upon it: seeing we have no Instance of a Plague, which was originally bred in that Country.
It is very remarkable, that the several Countries of Europe have always suffered more or less in this way, according as they have had a greater or lesser Commerce with Africa; or with those Parts of the East, that have traded thither. Which Observation, by the by, may help to solve a Difficulty concerning the great Increase of People among the Northern Nations in ancient Times, more than at present; for in those Ages, having no Communication at all with Africa, they were not wasted with Plagues, as they have been since.
As the People of Marseilles, from the first Foundation of their City by the Phoceans, were famous for Trade, and made long Voyages Southwards on the African Coast[38]; so they have in all times been very liable to the Plague. A French Author[39] in a History of the late Plague at Marseilles reckons up twenty Plagues that have happened in that City; notwithstanding it is by its situation one of the most healthy and pleasant Places in France, and the least subject to epidemic Distempers. But if we had no Records of this in History, an odd Custom among them, mentioned in Antiquity[40], of the way they made use of to clear themselves from this Distemper, would be a proof of it. Their manner at such times was, that some one poor Man offered himself to be maintained at the publick Expence with delicate Food for a whole Year: at the end of which he was led about the City dressed in consecrated Garments and Herbs; and being loaded with Curses as he went along, that the Evils of the Citizens might fall upon him, he was at last thrown into the Sea[41].
Agreeable to this Remark upon Trade is the Observation of Procopius in his forecited History, that the Plague was always found to spread from Maritime Places into the Inland Countries: which has ever since been confirmed by Experience.
Having shewn this Disease to be a Distemper of a distinct Species, and to take its Rise only in Africa; we must next seek for its Cause in that Country and no where else. We ought therefore to consider, what there is peculiar to that Country, which can reasonably be supposed capable of producing it. Wherefore I shall briefly set down as much as serves for this purpose of the State of Grand Cairo in Egypt, and of Æthiopia, the two great Seminaries of the Plague: Travellers relating that these Countries are more infested with it than most other Parts of Africa.
GRAND CAIRO is crouded with vast Numbers of Inhabitants, who for the most part live very poorly, and nastily; the Streets are very narrow, and close: it is situate in a sandy Plain at the Foot of a Mountain, which by keeping off the Winds, that would refresh the Air, makes the Heats very stifling. Through the midst of it passes a great Canal, which is filled with Water at the overflowing of the Nile; and after the River is decreased, is gradually dried up: Into this the People throw all manner of Filth, Carrion, &c. so that the Stench which arises from this, and the Mud together, is insufferably offensive[42]. In this Posture of things, the Plague every Year constantly preys upon the Inhabitants; and is only stopt, when the Nile, by overflowing, washes away this Load of Filth; the Cold Winds, which set in at the same time, lending their Assistance, by purifying the Air.
In Æthiopia those prodigious Swarms of Locusts, which at some times cause a Famine, by devouring the Fruits of the Earth, unless they happen to be carried by the Winds clear off into the Sea, are observed to entail a new Mischief upon the Country, when they die and rot, by raising a Pestilence[43]; the Putrefaction being hightened by the excessive Intemperance of the Climate, which is so very great in this Country, that it is infested with violent Rains at one Season of the Year, for three or four Months together[44]. And it is particularly observed of this Country, that the Plague usually invades it, whenever Rains fall during the sultry Heats of July and August[45], that is, as Lucretius expresses it, when the Earth is
Intempestivis pluviisque et solibus icta[46].
Now if we compare this last Remark of the Intemperance of the Climate in Æthiopia, with what the Arabian Physicians[47], who lived near these Countries, declare, that Pestilences are brought by unseasonable Moistures, Heats, and want of Winds; I believe we shall be fully instructed in the usual Cause of this Disease. Which from all these Observations compared together, I conclude to arise from the Putrefaction so constantly generated in these Countries, when that is hightened and increased by the ill State of Air now described; and especially from the Putrefaction of animal Substances.
It is very plain, that animal Bodies are capable of being altered into a Matter fit to breed this Disease: because this is the Case of every one who is sick of it, the Humours in him being corrupted into a Substance which will infect others. And it is not improbable, that the volatile Parts with which Animals abound, may in some ill States of Air in the sultry Heats of Africa be converted by Putrefaction into a Substance of the same kind: since in these colder Regions, we sometimes find them to contract a greater Degree of Acrimony than most other Substances will do by putrefying, and also more dangerous for Men to come within the reach of their Action; as in those pernicious, and even poysonous Juices, which are sometimes generated in corrupted Carcasses: Of which I have formerly given one very remarkable Instance[48], and, if it were necessary, many more might be produced, especially in hydropic Bodies, and in cancerous Tumors. Nay more, we find animal Putrefaction sometimes to produce in these Northern Climates very fatal Distempers, though they do not arise to the Malignity of the true Plague: For such Fevers are often bred, where a large Number of People are closely confined together; as in Goals, Sieges, and Camps.
And perhaps it may not be here amiss to remark, that the Egyptians of old were so sensible how much the Putridness of dead Animals contributed towards breeding the Plague, that they worshipped the Bird Ibis for the Service it did in devouring great Numbers of Serpents; which they observed did hurt by their Stench when dead, as well as by their Bite when alive[49].
But no kind of Putrefaction is ever hightened in these European Countries to a degree capable of producing the true Plague: and we learn from the Observation of the Arabian Physicians, that some Indisposition of the Air is necessary in the hottest Climates, either to cause so exalted a Corruption of the forementioned Substances, or at least to enforce upon Mens Bodies the Action of the Effluvia exhaled from those Substances, while they putrefy. Both which Effects may well be expected from the sensible ill Qualities of the Air before described, whenever they continue and exert their Force together any considerable time.
What I have here advanced of the first Original of the Plague, appears to me so reasonable, that I cannot enough wonder at Authors for quitting the Consideration of such manifest Causes for Hidden Qualities; such as Malignant Influences of the Heavens; Arsenical, Bituminous, or other Mineral Effluvia, with the like imaginary or uncertain Agents.
This however I do not say with design absolutely to exclude all Disorders in the Air, that are more latent than the intemperate Heat and Moisture before mentioned, from a Share in increasing and promoting the Infection of the Plague, where it is once bred: for I rather think this must sometimes be the Case; like to what is observed among us in relation to another infectious Distemper, namely, the Small-Pox, which is most commonly spread, and propagated by the same manifest Qualities of the Air as those here described: Notwithstanding which, this Distemper is sometimes known to rage with great Violence in the very opposite Constitution of Air, viz. in the Winter during dry and frosty Weather. But to breed a Distemper, and to give force to it when bred, are two different things. And though we should allow any such secret Change in the Air to assist in the first Production of the Disease; yet it may justly be censured in these Writers, that they should undertake to determine the Specific Nature of these secret Changes and Alterations, which we have no means at all of discovering: Since they do not shew themselves in any such sensible manner, as to come directly under our Examination; nor yet do their Effects, in producing the Plague, point out any thing of their Specific Nature.
All that we know, is this, that the Cause of the Plague, whatever it be, is of such a Nature, that when taken into the Body, it works such Changes in the Blood and Juices, as to produce this Disease, by suddenly giving some Parts of the Humours such corrosive Qualities, that they either excite inward Inflammations and Gangrenes, or push out Carbuncles and Bubo’s; the Matter of which, when suppurated, communicates the like Disease to others: But of the manner how this is done, I shall discourse in the following Chapter.
CHAP. II.
Of the Causes which spread the Plague.
I Have been thus particular in tracing the Plague up to its first Origine, in order to remove, as much as possible, all Objection against what I shall say of the Causes, which excite and propagate it among us. This is done by Contagion. Those who are Strangers to the full Power of this, that is, those who do not understand how subtile it is, and how widely the Distemper may be spread by Infection, ascribe the Rise of it wholly to the malignant Quality of the Air in all Places, wherever it happens; and, on the other hand, some have thought that the Consideration of the infectious Nature of the Disease must exclude all regard to the Influence of the Air: Whereas the Contagion accompanying the Disease, and the Disposition of the Air to promote that Contagion, ought equally to be considered; both being necessary to give the Distemper full force. The Design therefore of this Chapter, is to make a proper Balance between these two, and to set just Limits to the Effects of each.
For this purpose, I shall reduce the Causes, which spread the Plague, to three, Diseased Persons, Goods transported from infected Places, and a corrupted State of Air.
There are several Diseases, which will be communicated from the Sick to others: and this not done after the same manner in all. The Hydrophobia is communicated no other way than by mixing the morbid Juices of the diseased Animal immediately with the Blood of the sound, by a Bite, or what is analogous thereto; the Itch is given by simple Contact; the Lues Venerea not without a closer Contact; but the Measles, Small-Pox, and Plague are caught by a near Approach only to the Sick: for in these three last Diseases Persons are render’d obnoxious to them only by residing in the same House, and conversing with the Sick.
Now it appears by the Experiments mentioned in the Preface, of giving the Plague to Dogs by putting the Bile, Blood or Urine from infected Persons, into their Veins, that the whole mass of the animal Fluids in this Disease is highly corrupted and putrefied. It is therefore easy to conceive how the Effluvia or Fumes from Liquors so affected may taint the ambient Air. And this will more especially happen, when the Humours are in the greatest Fermentation, that is, at the Highth of the Fever: as it is observed that fermenting Liquors do at the latter end of their intestine Motion throw off a great Quantity of their most subtile and active Particles. And this Discharge will be chiefly made upon those Glands of the Body, in which the Secretions are the most copious, and the most easily increased: such are those of the Mouth and Skin. From these therefore the Air will be impregnated with pestiferous Atoms: which being taken into the Body of a sound Person will, in the Nature of a Ferment, put the Fluids there into the like Agitation and Disorder.
The Body, I suppose, receives them these two ways, by the Breath, and by the Skin; but chiefly by the former.
I think it certain that Respiration does always communicate to the Blood some Parts from the Air: Which is proved from this Observation, that the same Quantity of Air will not suffice long for breathing, though it be deprived of none of those Qualities, by which it is fitted to inflate the Lungs and agitate the Blood, the Uses commonly ascribed to it. And this is farther confirm’d by what the learned Dr. Halley has inform’d me, that when he was several Fathom under Water in his Diving Engine, and breathing an Air much more condensed than the natural, he observed himself to breath more slowly than usual: Which makes it more than probable, that this conveying to the Blood some subtile Parts from the Air, is the chief Use of Respiration; since when a greater Quantity of Air than usual was taken in at a time, and consequently more of these subtile Parts received at once by the Blood, a less frequent Respiration sufficed.
As to the Skin, since there is a continual Discharge made thro’ its innumerable Pores, of the matter of insensible Perspiration and Sweat; it is very possible that the same Passages may admit subtile Corpuscles, which may penetrate into the inward Parts. Nay it is very plain that they do so, from what we observe upon the outward Application of Ointments and warm Bathings: which have their Effects by their finest and most active Parts insinuating themselves into the Blood.
It is commonly thought, that the Blood only is affected in these Cases by the morbific Effluvia. But I am of opinion, that there is another Fluid in the Body, which is, especially in the beginning, equally, if not more, concerned in this Affair: I mean the Liquid of the Nerves, usually called the Animal Spirits. As this is the immediate Instrument of all Motion and Sensation, and has a great Agency in all the glandular Secretions, and in the Circulation of the Blood itself; any considerable Alteration made in it must be attended with dangerous Consequences. It is not possible that the whole Mass of Blood should be corrupted in so short a Time as that, in which the fatal Symptoms, in some Cases, discover themselves. Those Patients of the first Class, mentioned in the beginning of this Discourse, particularly the Porters who opened the infected Bales of Goods in the Lazaretto’s of Marseilles, died upon the first Appearance of Infection, as it were by a sudden Stroke; being seized with Rigors, Tremblings, Heart-Sickness, Vomitings, Giddiness and Heaviness of the Head, an universal Languor and Inquietude; the Pulse low and unequal: and Death insued sometimes in a few Hours.
Effects so sudden must be owing to the Action of some Corpuscles of great Force insinuated into, and changing the Properties of, another subtle and active Fluid in the Body: and such an one, no doubt, is the Nervous Liquor.
It is not to be expected that we should be able to explain the particular manner by which this is brought about. We know too little of the Frame of the Universe, and of the Laws of Attractions, Repulsions and Cohesions among the minutest Parcels of Matter, to be able to determine all the Ways by which they affect one another, especially within animal Bodies, the most delicate and complicated of all the known Works of Nature. But we may perhaps make a probable Conjecture upon the Matter. Our great Philosopher, whose surprising Discoveries have exceeded the utmost Expectations of the most penetrating Minds, has demonstrated that there is diffused through the Universe a subtile and elastic Fluid of great Force and Activity. This he supposes to be the Cause of the Refraction and Reflection of the Rays of Light; and that by its Vibrations Light communicates Heat to Bodies: and, moreover, that this readily pervading all Bodies, produces many of their Effects upon one another[50].
Now it is not improbable that the Animal Spirits are a thin Liquor, separated in the Brain, and from thence derived into the Nerves, of such a Nature that it admits, and has incorporated with it, a great Quantity of this elastic Fluid: which makes it a vital Substance of great Energy. And a Liquor of this kind must be very susceptible of Alterations from other active Bodies of a different Nature from it, if they approach to and are mixed with it: as we see some Chemical Spirits upon their being put together, fall into a Fermentation, and make a Composition of a quite different kind.
If therefore we allow the Effluvia or Exhalations from a corrupted Mass of Humours in a Body that has the Plague to be volatile and firey Particles, carrying with them the Qualities, of those fermenting Juices from which they proceed; it will not be hard to conceive how these may, when received into the nervous Fluid of a sound Person, excite in it such intestine Motions as may make it to partake of their own Properties, and become more unfit for the Purposes of the animal Oeconomy. But of this more in another Place.
This is one means by which the Plague, when once bred, is spread and increased: but the second of the forementioned Causes, namely, Goods from infected Places, extends the Mischief much wider. By the preceding Cause, the Plague may be spread from Person to Person, from House to House, or perhaps from Town to Town, tho’ not to any great Distance; but this carries it into the remotest Regions. From hence the trading Parts of Europe have their principal Apprehensions, and universally have recourse to Quarantaines for their Security. The Universality of which Practice is a strong Argument, that Merchandize will communicate Infection: for one cannot imagine, that so many Countries should agree in such a Custom without the most weighty Reasons. But besides, there is not wanting express Proof of this, from particular Examples, where this Injury has been done by several sorts of Goods carried from infected Places to others. Some of these I shall hereafter be obliged to mention; at present I shall confine my self to three Instances only. The first shall be of the Entrance of the Plague into Rome in the Year 1656, which we are assured was conveyed thither from Naples by Clothes and other Wares from that Place, brought first to Port Neptuno, and carried from thence to the Neighbouring Castle of St. Lawrence: which after having been kept some time there, were conveyed into Rome[51]. The second Instance I shall take is from the Account given us of the Entrance of the Plague into Marseilles[52]; which being drawn up with great Exactness, may be the more rely’d on. It appears indisputably by this Account, that the Mischief was brought thither by Goods from the Levant. For the first, who had the Distemper, was one of the Crew of the Ship, which brought those Goods: the next were those, who attended upon the same Goods, while they were under Quarantaine; and soon after the Surgeon, whom the Magistrates of Marseilles appointed to examine the Bodies of those, who died.
This Relation, if duly consider’d, is, I believe, sufficient to remove all the Doubts any one can have about the Power of Merchandize to convey Infection: for it affords all the Evidence, the most scrupulous can reasonably desire. Possibly there might be some Fever of extraordinary Malignity in Marseilles, such as is commonly called Pestilential, before the Arrival of these Goods: But no such Fever has any indisputable Right to the Title of Pestilence, as I have before shewn. On the contrary, these two, the real Pestilence, and such Pestilential Fevers, must carefully be distinguished, if we design to avoid all Mistakes in reasoning upon these Subjects.
Some such Fever of uncommon Malignity, I say, might perhaps be in Marseilles before the Arrival of these Goods. There might likewise perhaps be an Instance or two of Fevers attended with Eruptions, bearing some Resemblance to those of the Plague: for such I my self have sometimes seen here in London. But it is not conceivable, that there should be any Appearance of the true Plague before that time: for it was full six Weeks from the time of the Sailor’s Death, which had given the Alarm, and raised a general Attention, before the Magistrates received Information of any one’s dying of the Plague in the City. And I believe it was never known, that the Plague, being once broke out, gave so long a Truce in hot Weather.
The Plague, which has this present Year almost depopulated Messina, affords a third Instance of the same kind. By an authentic Relation of it, published here[53] we are informed, that a Genoese Vessel from the Levant, arrived at that City; and upon notice given that a Sailor, who had touched some Cases of Cotton Stuffs bought up at Patrasso in the Morea, where the Distemper then raged, was dead of the Plague, in the Voyage; the Ship was put under Quarantaine: during which time the Cotton Stuffs were privately landed. The Master and some Sailors dying three days after, the Vessel was burnt. These Goods lay for some time concealed, but were soon after publickly sold: upon which the Disease immediately broke out in that Quarter where they were opened; and afterwards was spread through the whole City.
I think it not improper, for the fuller Confirmation of the present Point, to give a Relation communicated to me by a Person of unquestionable Credit, of the like Effect from Goods, in respect to the Small-Pox; which Distemper is frequently carried in the Nature of the Plague both to the East and West-Indies from these Countries, and was once carried from the East-Indies to the Cape of Good Hope, in the following manner. About the Year 1718, a ship from the East-Indies arrived at that Place: In the Voyage three Children had been sick of the Small-Pox: The foul Linen used about them was put into a Trunk, and lock’d up. At the Ship’s Landing, this was taken out, and given to some of the Natives to be washed: Upon handling the Linen, they were immediately seized with the Small-Pox, which spread into the Country for many Miles, and made such a Desolation, that it was almost dispeopled.
It has been thought so difficult to explain the manner how Goods retain the Seeds of Contagion, that some[54] Authors have imagined Infection to be performed by the Means of Insects; the Eggs of which may be conveyed from Place to Place, and make the Disease when they come to be hatched. But as this is a Supposition grounded upon no manner of Observation, so I think there is no need to have recourse to it. If, as we have conjectured, the Matter of Contagion be an active Substance generated chiefly from animal Corruption; it is not hard to conceive how this may be lodged and preserved in soft porous Bodies, which are kept pressed close together.
We all know how long a time Perfumes hold their Scent, if wrapt up in proper Coverings: And it is very remarkable, that the strongest of these, like the Matter we are treating of, are mostly animal Juices, as Mosch, Civet, &c. and that the Substances, found most fit to keep them in, are the very same with those, which are most apt to receive and communicate Infection, as Furrs, Feathers, Silk, Hair, Wool, Cotton, Flax, &c. the greatest part of which are likewise of the animal kind.
Nothing indeed can give us so just a Notion of Infection, and more clearly represent the manner of it, than Odoriferous Bodies. Some of these do strangely revive the animal Spirits; others instantaneously depress and sink them: We may therefore conceive that, what active particles emitted from any such Substances do, is in the like way done by Pestiferous Bodies; so that Contagion is no more than the effect of volatile offensive Matter drawn into the Body by our Smelling.
The third Cause we assigned for the spreading of Contagion, was a corrupted State of Air. Although the Air be in a right State, yet a sick Person may infect those who are very near him: As we find the Pestilence to continue sometimes among the Crew of a Ship, after they have sailed out of the Infectious Air wherein the Disease was first caught. A remarkable Accident of this Nature is recorded to have happened in the Plague at Genoa in the Year 1656. Eleven Persons put to Sea in a Felucca, with design to withdraw themselves from the Contagion, and retire into Provence; but one of them falling sick of the Plague soon after they had imbarked, infected the rest; insomuch that others being taken ill, and dying in their turns, they were not admitted any where, but were forced to return from whence they came: and by that time the Boat arrived again at Genoa no more than one of them survived[55].
However in this Case the Malady does not usually spread far, the contagious Particles being soon dispersed and lost. But when in a corrupt Disposition of the Air the contagious Particles meet with the subtile Parts generated by that Corruption, by uniting with them they become much more active and powerful, and likewise of a more durable Nature; so as to form an infectious Matter capable of conveying the Mischief to a greater distance from the diseased Body, out of which it was produced.
In general, a hot Air is more disposed to spread Contagion than a cold one, as no one can doubt, who considers how much all kinds of Effluvia are farther diffused in a warm Air, than in the contrary. But moreover, that State of Air, when unseasonable Moisture and want of Winds are added to its Heat, which gives birth to the Plague in some Countries, will doubtless promote it in all. For Hippocrates sets down the same Description of a Pestilential State of Air in his Country, as the Arabians do of the Constitution, which gives Rise to the Plague in Africa[56]. Mercurialis assures us the same Constitution of Air attended the Pestilence in his time at Padua[57]: and Gassendus observed the same in the Plague of Digne[58]. Besides, it is easy to shew how the Air, by the sensible ill Qualities discoursed of in the last Chapter, should favour infectious Diseases, by rendering the Body obnoxious to them.
Indeed other hurtful Qualities of the Air are more to be regarded than its Heat alone: for the Plague is sometimes stopt, while the Heat of the Season increases, upon the Emendation of the Air in other respects. At Smyrna the Plague, which is yearly carried thither by Ships, constantly ceases about the 24th of June, by the dry and clear Weather they always have at that time: the unwholsome Damps being then dissipated that annoy the Country in the Spring. However, the Heat of the Air is of so much Consequence, that if any Ship brings it in the Winter Months of November, December, January, or February, it never spreads: but if later in the Year, as in April or afterwards, it continues till the time before mentioned.
But moreover, what was said before of some latent Disorders in the Air having a share in spreading the Plague, will likewise have place in these Countries; as the last Plague in the City of London remarkably proves, the Seeds of which, upon its first Entrance, and while it was confined to a House or two, preserved themselves through a hard frosty Winter, and again put forth their malignant Quality as soon as the Warmth of the Spring gave them force: but, at the latter end of the next Winter they were suppressed so as to appear no more, though in the Month of December more than half the Parishes of the City were infected.
A corrupted State of Air is, without doubt, necessary to give these contagious Atoms their full force; for otherwise it were not easy to conceive how the Plague, when once it had seized any Place, should ever cease but with the Destruction of all the Inhabitants: Which is readily accounted for by supposing an Emendation of the Qualities of the Air, and the restoring of it to a healthful State capable of dissipating and suppressing the Malignity.
On the other hand, it does not appear, that the Air, however corrupted, is usually capable of carrying Infection to a very great distance; but that commonly the Plague is spread from Town to Town by infected Persons and Goods: for there are numberless Instances, where the Plague has caused a great Mortality in Towns, while other Towns and Villages, very near them, have been entirely free. And hence it is, that the Plague sometimes spreads from Place to Place very irregularly. Thuanus[59] speaks of a Plague in Italy, which one Year was at Trent and Verona, the next got into Venice and Padua, leaving Vicenza, an intermediate Place, untouched, though the next Year that also felt the same Stroke: a certain Proof that the Plague was not carried by the Air from Verona to Padua and Venice; for the infected Air must have tainted all in its Passage. We have had lately in France one Instance of the same Nature, when the Plague was carried at once out of Provence several Leagues into the Gevaudan. Usually indeed the Plague, especially when more violent than ordinary, spreads from infected Places into those which border upon them: which probably is sometimes effected by some little Communication infected Towns are obliged to hold with the Country about them for the sake of Necessaries, the Subtlety of the Venom now and then eluding the greatest Precautions; and at other times by such as withdraw themselves from infected Places into the Neighbourhood.
I own it cannot be demonstrated, that when the Plague makes great Ravage in any Town, the Number of Sick shall never be great enough to load the Air with infectious Effluvia, emitted from them in such Plenty, that they may be conveyed by the Winds into a neighbouring Town or Village without being dispersed so much as to hinder their producing any ill Effects; especially since it is not unusual for the Air to be so far charged with these noxious Atoms, as to leave no Place within the infected Town secure: insomuch that when the Distemper is at its Highth, all shall be indifferently infected, as well those who keep from the Sick, as those who are near them; though at the beginning of a Plague to avoid all Communication with the Diseased, is an effectual Defence. However, I do not think this is often the Case: just as the Smoak, with which the Air of the City of London is constantly impregnated, especially in Winter, is not carried many Miles distant; though the Quantity of it is vastly greater than the Quantity of infectious Effluvia, that the most mortal Plague could generate.
But, to conclude what relates to the Air, since the ill Qualities of it in these Northern Countries are not alone sufficient to excite the Plague, without imported Contagion, this shews the Error of a common Opinion, countenanc’d by Authors of great Name[60], that we are necessarily visited with the Plague once in thirty or forty Years: which is a mere Fancy, without Foundation either in Reason or Experience; and therefore People ought to be delivered from such vain Fears. Since the Pestilence is never originally bred with us, but always brought accidentally from abroad, its coming can have no relation to any certain Period of Time. And although our three or four last Plagues have fallen out nearly at such Intervals, yet that is much too short a Compass of Years to be a Foundation for a general Rule. Accordingly we see that almost fourscore Years have passed over without any Calamity of this kind.
The Air of our Climate is so far from being ever the Original of the true Plague, that most probably it never produces those milder infectious Distempers, the Small-Pox and Measles. For these Diseases were not heard of in Europe before the Moors had entered Spain: and (as I have observed in the Preface) they were afterwards propagated and spread through all Nations, chiefly by means of the Wars with the Saracens.
Moreover, we are so far from any Necessity of these periodical Returns of the Plague, that, on the contrary, though we have had several Strokes of this kind, yet there are Instances of bad Contagions from abroad being brought over to us, which have proved less malignant here, when our Northern Air has not been disposed to receive such Impressions.
The Sweating Sickness, before hinted at, called Sudor Anglicus and Febris Ephemera Britannica, because it was commonly thought to have taken its Rise here, was most probably of a foreign Original: and though not the common Plague with Glandular Tumors, and Carbuncles, yet a real Pestilence from the same Cause, only altered in its Appearance, and abated in its Violence, by the salutary Influence of our Climate. For it preserved an Agreement with the common Plague in many of its Symptoms, as excessive Faintness and Inquietudes, inward Burnings, &c. these Symptoms being no where observed in so intense a Degree as here they are described to have been, except in the true Plague: And, what is much more, it was likewise a contagious Disease.
The first time this was felt here, which was in the Year 1485, it began in the Army, with which King Henry VII. came from France and landed in Wales[61]: and it has been supposed by some to have been brought from the famous Siege of Rhodes by the Turks three or four Years before, as may be collected from what Dr. Keyes says in one Place of his Treatise on this Disease[62]. Besides, of the several returns which this has made since that time, viz. in the Years 1506, 1517, 1528, and 1551, that in the Year 1528 may very justly be suspected to have been owing to the common Pestilence, which at those times raged in Italy[63] as I find one of our Historians has long ago conjectured[64]: and the others were very probably from a Turkish Infection. If at least some of these Returns were not owing to the Remains of former Attacks, a suitable Constitution of Air returning to put the latent Seeds in Action before they were quite destroyed. It is the more probable that this Disease was owing to imported Contagion; because we are assured, that this Form of the Sickness was not peculiar to our Island, but that it made great Destruction with the same Symptoms in Germany, and other Countries[65].
I call this Distemper a Plague with lessened Force: because though its carrying off thousands for want of right Management was a Proof of its Malignity, which indeed in one respect exceeded that of the common Plague itself (for few, who were destroyed with it, survived the Seizure above one Natural Day) yet its going off safely with profuse Sweats in twenty four Hours, when due care was taken to promote that Evacuation, shewed it to be what a learned and wise Historian calls it, rather a Surprize to Nature, than obstinate to Remedies; who assigns this Reason for expressing himself thus, that if the Patient was kept warm with temperate Cordials, he commonly recovered[66]. And, what I think yet more remarkable, Sweating, which was the natural Crisis of this Distemper, has been found by great Physicians the best Remedy against the common Plague: by which means, when timely used, that Distemper may sometimes be carried off without any external Tumors. Nay besides, a judicious Observer informs us, that in many of his Patients, when he had broken the Violence of the Distemper by such an artificial Sweat, a natural Sweat not excited by Medicines would break forth exceedingly refreshing[67].
And I cannot but take notice, as a Confirmation of what I have been advancing, that we had here the same kind of Fever in the Year 1713, about the Month of September, which was called the Dunkirk Fever, as being brought by our Soldiers from that Place. This probably had its Original from the Plague, which a few Years before broke out at Dantzick, and continued some time among the Cities of the North. With us this Fever began only with a Pain in the Head, and went off in large Sweats usually after a Day’s Confinement: but at Dunkirk it was attended with the additional Symptoms of Vomiting, Diarrhœa, &c.
To return from this Digression: From all that has been said, it appears, I think, very plainly, that the Plague is a real Poison, which being bred in the Southern Parts of the World, is carried by Commerce into other Countries, particularly into Turky, where it maintains itself by a kind of Circulation from Persons to Goods: which is chiefly owing to the Negligence of the People there, who are stupidly careless in this affair. That when the Constitution of the Air happens to favour Infection, it rages there with great Violence: that at that time more especially diseased Persons give it to one another, and from them contagious Matter is lodged in Goods of a loose and soft Texture, which being pack’d up and carried into other Countries, let out, when opened, the imprisoned Seeds of Contagion, and produce the Disease whenever the Air is disposed to give them force; otherwise they may be dissipated without any considerable ill Effects. And lastly, that the Air does not usually diffuse and spread these to any great Distance, if Intercourse and Commerce with the Place infected be strictly prevented.
