BUT a hot and moist Air is very different. By _Moist_, is meant what arises from sudden or long Rains. This is the Const.i.tution of Air that most Authors charge with being the greatest Instrument in _Pestilential Distempers_. _Hippocrates_[29] ascribes a great deal to such an Air, and relates a _Pestilence_ that had its Rise from great Heat, joined with _Southerly_ Winds and much Rain. _Galen_ is of the same Mind, as appears from several of his Writings[30], with many others too tedious to mention.
The Truth of this is likewise manifest from the Histories of those Countries, where there are long settled Heats, and afterwards much Rain, as in several Parts of the _East-Indies_, which are known at such Times to be most grievously afflicted with Fevers and Diseases of a very malignant Kind. The same we are informed of from some Places in _Africa_,[31], _viz._ That if Showers fall soon upon the sultry Heats of _July_ and _August_, pestilential Distempers certainly ensue. It may be generally observed here too in our own Climate, that the most unhealthful Times are after warm Rains, and the more if the Air is then agitated but little with Winds.
FROM a cold and moist Air, we have little complained of, as to their occasioning these Diseases, unless such a Const.i.tution sets in immediately upon a contrary Extream; for all sudden Changes of Weather are more or less unhealthful, as well as in other Respects of living; for which Reason particularly, _Corn. Celsus_ advises to be very slow in all Alterations of Moment: And _Sanctorius_ frequently inculcates the same in his _Aphorisms_, and tells us[32] how it is hurtful, both to go suddenly out of a hot Air into a cold one, and out of a cold Air into a hot one; and is also very particular[33] in the Inconveniencies of such a Const.i.tution of Air we are now speaking of, setting in after the Heat of Summer.
_Hippocrates_[34] does tell us of a _Pestilence_ from long continued cold Rains, as likewise does _Fernelius_[35], but such Instances are not common.
THE last Const.i.tution of Air we are to take Notice of, is that which is cold and dry, against which there are a great many very heavy Complaints.
_Galen_ writes of a most Raging Pestilence about _Aquileia_ in _Italy_, that began in the very Middle of Winter, and had its manifest Cause in extream Cold. _Fernelius_[36] a.s.serts the Rise of several Pestilences from the same Causes: As also does _Morellus_[37] observe great Malignities to proceed from some _Northerly_ cold Winds. _t.i.tus Livy_[38] likewise mentions a _Pestilential Const.i.tution_ arising from intense Cold, but _Physical Histories_ abound with such Relations.
OF the strange and sudden Effects of intense Cold and dry Winds, we have very surprizing Accounts from those who have travelled into Countries where they are the most frequent. Dr. _Bernard Connor_[39]
beforementioned, relates, That when he was in _Poland_, it was a.s.serted to him by very creditable Testimonies, that it frequently happens in _Lithuania_, and some of the _Northern_ Tracts of _Muscovy_ and _Tartary_; that if sometimes, through the Neglect of the Shepherds, their small Cattle, as _Sheep_, _Goats_, and the like, be left exposed in the Night-time to the _Northerly Winds_, they are frequently found next Morning perfectly stiff and dead, in the same Posture as they are wont to be in at their Stalls and Cribs: And there are divers Accounts of Persons in those Countries, who have been so suddenly transfixed, stiffened, and killed by those _Blasts_, as to have continued on Horseback in the same Posture as when Living, till the Horse, acquainted with the Road, has brought them to their Journey"s End: And the above-mentioned Physician[40]
tells us, that when he was at _Brussels_, he was informed by a _Spanish_ Captain, that of a Party of Horse that was sent out for Booty in a very cold Season, one by Accident lost the rest of the Body; and Riding about some time, before he could find his Way, or any Refreshment, he was so transfixed with the Cold as to be quite killed, but continued on Horseback in the Posture of a Live Person, until his Horse at last happened to find the Way back to his Quarters, whither his Company had before got, and missing him, feared he had fallen into the Enemies Hands; but when they came to congratulate him upon his safe Return, they went so near as to speak to him, and take hold of him, before they perceived him to be dead.
TO _Blasts_ of this kind it undoubtedly is, that Fruit Trees and Plants do so frequently suffer, especially after a warm early Spring, after the vegetable Juices have began to rise and shoot into Buds and Leaves.
Instances of this Nature we frequently find in our own Countrey; and I have had Opportunity to observe, more than once, that upon such _Blasts_, the Trees have, on that side towards the Wind, been in one Night"s Time quite changed in the Colour of the Leaves; and some, of the most tender sort, almost stripped bare, their Leaves falling off dry, as in _Autumn_.
BUT there is something yet further, besides particular Const.i.tutions of Air, that is taken Notice of by Physicians, as a general Cause of Maladies of this kind; and that is what is commonly called _Contagion_ or _Infection_; by this Term _Contagion_, is understood a Disease arising from the Contact of such Bodies or Particles as have in them a Power of Altering the due Crasis of a healthful Person, and inducing still one common Disease; these Particles are generally called by Physical Writers ?asata, _Contagiosa_, or _Contagij Seminia_; and the Difference of Pestilences arising from these Causes seems much to differ from what have been hitherto taken Notice of, as the former cannot be shunned but by quite leaving the diseased Climate, or by such a Strength, or Turn of Const.i.tution, as resists, or yeilds not to the general Disorder; whereas in this last Case, a Person seems to be equally safe in any Air that is not impregnated with these contagious _Effluvia_, and the greatest Danger arises from the Nearness to diseased Persons, or whatsoever else is capable of harbouring those mischievous and secret Messengers, as the Poet[41] takes Notice.
_Quo proprior quisq; est, servitq; fidelius agro In partem Lethi citius venit.----_
THE Histories of Physick abound with Relations of Pestilences from no other Cause than what arises from the Importation of the Disease, if it may be so termed, from distant Countries; and sometimes not by Persons themselves distempered, but by the Conveyance of these _Pestilential Miasmas_ in their Cloaths or Wares imported in the Way of Trade.
_Fracastorius_,[42] an eminent _Italian_ Physician, tells us, That in the Year Fifteen Hundred and Eleven, when the _Germans_ were in Possession of _Verona_, there arose a deadly Disease amongst the Soldiers from the Wearing only a Coat purchased for a small Value; for it was observed, that every Owner of it soon sickened and died; until, at last, the Cause was so manifestly from some Infection in the Coat, that it was ordered to be burned. Ten Thousand Persons, he says, were computed to fall by this Plague before it ceased.
FROM the same Cause, that is, infected Garments, and Merchandize, _Mercurialis_ takes Notice of a Plague in his Time at _Venice_; and _Appia.n.u.s Alexandrinus_[43] a.s.sures us, that the _Celtae_, after a Conquest over the _Illyrici_, and in Possession of their Plunder, were infected with a grievous Plague, which the _Illyrici_ then laboured under.
_Thycidides_ also, in his Relation of the Plague at _Athens_, intimates, That it was brought from some Part of _Ethiopia_ by the like Means. And _Prosper Alpinus_[44], before mentioned, seems to lay the greatest Stress for the Frequency of the Plague at _Grand Cairo_, to the Traffick with those Countries as are hardly ever free from _Pestilential Diseases_. A great many Physicians have charged the Plague in Sixteen hundred and sixty three at _Amsterdam_, to the Infection of some _Pestilential Miasms_ which were transported from _Smyrna_ and _Algiers_, then much infected with such Diseases, with some Merchandize; by which Means likewise it was conjectured soon afterwards to reach _London_, and several other Parts of _England_, as it appears from the preceding Account of Dr. _Hodges_. To this Purpose I remember to have read a strange Story, somewhere in _Baker_"s Chronicle, of a great Rot amongst Sheep, which was not quite rooted out until about Fourteen Years Time, that was brought into _England_ by a Sheep bought for its uncommon Largeness, in a Country then infected with the same Distemper: And upon this Account it is that the Prudence of those Nations and States are to be justified, who enjoin all Persons and Merchandize from infected Countries, to stay a certain Time upon their Coasts and Borders before they are suffered to intermix with a healthful People; having by such Instances as here mentioned been justly alarmed at the Incroachment of such dreadful Destroyers.
THESE Historical Fragments are put together, in Order to apprize those Readers who have not been very conversant with Things of this Kind, with the various Ways by which the most dangerous Diseases, and even sudden Death, may be introduced into our Const.i.tutions, by the Agency of very minute and unheeded Causes; and likewise the better to support the Distinction necessary to be made between _Epidemic_ Diseases, and a _Contagion_; as well as to ill.u.s.trate the Manner whereby the latter subsists, spreads, and proves fatal, when the Causes producing the former are absent.
_Epidemic_ Diseases of all Kinds and Degrees of Exacerbation, have their Rise from some common Cause, that affects all within its Extent more or less, in Proportion to the particular Fitness of different Const.i.tutions to be affected by it: And by the _Bellinian_ Doctrine we are taught, how all those Changes are made in the Blood, when thrown into a Fever by these Causes, even from the most simple _Ephemera_, to the most complicated and malignant Cases whatsoever; to which therefore the Reader must be referred, for a clear Understanding of such Matters; it being sufficient to our Purpose here to observe, that he demonstrates all Fevers to be attended with some Fault in the Blood"s Motion, Quant.i.ty, or Quality, or in some or all of them together; and that its chief Fault in Quality, (which is most to the present Case) consists in an unequable Fluidity, some Parts of it being rendered thinner, and others thicker at the same Time, than in a natural State; not unlike what happens to all coagulated Liquors.
FROM this Condition of Blood, this great and wonderful Man goes on to shew, through the whole Course of his Propositions, that the coagulated Part, which he commonly distinguishes by the Name of _Lentor_, does acc.u.mulate in the capillary Vessels until their Endeavours of Rest.i.tution, as in all Elastick Bodies, are greater than the protruding Force, when by the Arteries Re-action upon it, the _Lentor_ is shook, dislodged, and washed away into the Veins, and ordinary Course of Circulation, there continuing its Progress till it is either fitted for some Secretion and Evacuation, or again lodged in the Capillaries, to bring on a new Paroxysm.
THIS unequable Fluxility of the Blood arises from two general Causes, either from such Means as diminish its Motion, or from the Mixture of such Particles, as cannot only of themselves be reduced by the digestive Powers into h.o.m.ogeneous Dispositions therewith; or as have a Faculty to put in Fusion some Parts of the Ma.s.s, and leave the other thicker than before; these are particularly enumerated, and their Ways of Operation distinctly demonstrated by _Bellini_.
CONFORMABLE to this Change in the Blood, which is the common Promptuary of all the other animal Fluids, every Thing separated from it hath some correspondent Affections; and the nervous Fluid in particular, which is separated from a Ma.s.s so unequally fluid, cannot but in it self have some Parts too fine, and others too gross, besides the Inequalities in the Times and Quant.i.ties of its Separation; from all which the same Author accounts for those Affections, termed nervous, which are the _Concomitants_ of Fevers: And in the Prosecution hereof he frequently takes Occasion to speak of this Fluid to be thin, sharp, hot, fiery, dry, _&c._ as the saline and rigid Parts in its Composition are by the Distemper more or less subtilized, or more or less defrauded of its humid Parts by Exhalation.
FURTHERMORE, in this great Disorder of the Const.i.tution, and inordinate Hurry and Colluctation of the Fluids, sometimes the Solids are maintained in their Contractions and Motions, until the Particles either introduced from Abroad, or generated in the Body, which cannot be a.s.simulated into h.o.m.ogeneous Qualities, are thrown out of the Course of Circulation by the natural Discharges, by Transpiration, or by Abcesces; and the animal Fluids restored to their natural State. But when Matters are brought to this pa.s.s, it happens that the very Means of saving one Person, may prove the Destruction of many others; because what is thus critically thrown off by one, hath a Faculty of exciting the like Disorders in the Fluids of another, when it is insinuated into them; as a very small Quant.i.ty of some fermenting Substances will communicate its Efficacies a very great Way, and put very great Parcels of Fluid into the like Agitation. And this is the Way by which a malignant Fever comes to be infectious, and a _Pestilence_ changes into a _Contagion_; as _Bellini_ more largely explains it in his XXVIII_th Proposition_ of Fevers; from the whole of which it is manifest, as Dr. _Mead_ hath expressed it in his fifth _Essay of Poisons_, that _the Effects of the +one+ are the Cause and Beginning of the +other+_.
TO bring then this nearer to the Matter under Examination, the Plague which is described in the foregoing Pages, was strictly and properly a _Contagion_, and by all Accounts of the best Authority, That which hath made such vast Devastations in some Parts of _France_, and now continues to rage amongst them, to the great Terror of their Neighbours, is also of the same Kind; and was brought to them in Merchandize, and by a Ship"s Crew, who were sick of a pestilential Disease all their Voyage Home from some Parts of _Turkey_; in neither of these there being any Manner of Fault chargeable upon the Air, or to any other Causes before enumerated in producing a _Pestilence_.
THE Symptoms of That now Abroad are reported by the best Physicians amongst them to be _sudden Pains in the Head_, _great Loathing at Stomach_, _Reaching to Vomit_, _Consternation_, _wild Looks_, _trembling Voice_, _Coldness in the extreme Parts_, _low unequal Pulse_, _Paleness_, _Delirium_, _Convulsions_, _Carbuncles_, _Buboes_, _livid Vesications_, _purple Spots_, _and Hemorrhages_; _the last are certain Forerunners of Death_. All which, more or less, are the constant Attendants of all pestilential Fevers.
BECAUSE then there is such a vast Difference between a _Pestilence_ arising from a.s.signable Causes in the Air, _&c._ and a _Pestilence_ from a _Contagion_, as to the preservative Means especially against them; and that what we are now in most Apprehension of, is of the latter Kind; it most concerns us to be well acquainted with the Manner of Infection, as far as we can reason about Agents so extreamly minute and subtle. How all other _Antecedents_ to a _Pestilence_ exert themselves in their Influences over the animal OEconomy, _Bellini_ has brought even to a Demonstration; but as to a _Contagion_, he says little; which therefore, as introductory to some following Remarks, we shall here insert.
"As this Coagulation and Fusion may go on so far as to set at Liberty, and perspire through the Surface of the Body, or with the Breath in Respiration, many noxious Particles, which may be so subtil and active, as to enter the cutaneous Pores of other Persons, or mix with that Air which they draw in Respiration, and when got into the Body, be able to make the same Change in the Blood, both as to its Coagulation and Fusion; hence it comes that such a Fever proves _contagious_, which is an inseparable Requisite to a _pestilential_ Fever.
"But this is not only thus brought about; but also the dissolved, and dispersed Particles may longer adhere to some inanimate Bodies than others, as to Woollen and Linen Cloaths, Papers, _&c._ and these Particles may, by the Steam of a living Body, or by the Means of any other Heat, be put into Motion, so as to breath out of those Lodgments, where they quietly resided, and obtain so much Liberty, and Action on all sides, as will carry them into the cutaneous Pores of any Persons within their Reach, and infect them; and on this Account a _Pestilence_ may be brought from very distant Countries, lying a long Time in such Manner concealed, and then suddenly breaking out; with many other Circ.u.mstances of like Nature.
"BUT if these subtile and active Particles be of that Nature, that they can penetrate the Pores of other Animals, and occasion a like Coagulation of their Blood, not only Men, but Brutes also, will be seized with a _Pestilence_; but this does not always very necessarily happen; because the Blood of Animals is different from humane Blood, so that although these Particles are supposed to get into it, it does not therefore necessarily follow that they must vitiate it, any more than will _Aqua Regia_ dissolve all kinds of Metals; but yet Brutes of all kinds, or some of them only, will be seized equally with Men, when this subtile and active Ferment, which penetrates the Surface, is of that Nature, as will taint the Blood of other Animals with those _pestilential_ Requisites.
"AS this kind of Contagion then can easily proceed from an infected Person at a great Distance, as often as the noxious Particles can reach another Person, and give that Degree of Coagulation and Fusion, as is necessary to a _Pestilence_; the more aggravated then will be this Calamity, and more easily spread, when a healthful Person is near to one already infected; and yet much more worse, if it is in Contact with those Parts, which more plentifully, and with a greater _Impetus_, breath out infected Steams, as if the Air arising from the Mouth and Lungs, which must be extreamly hot, or the Perspiration of a Carbuncle when it is greatly inflamed; for in this Case the exhaling Particles will be in their greatest Activity when nearest the recipient Body, and likewise more dense, that is, more numerous, and consequently of greatest Efficacy.
"BUT it is not every one that is seized with a _Pestilence_ from Contagion, by Means of Steams exhaling from any particular Parts of the Body; but only when these Steams, and the Air it self, hath joined with, and interspersed through it Particles of vitiated Faculties; and then this Kind of Fever will easily be communicated, and necessarily ensue, not only on Account of what gets into the Body with the inspired Air, but because also the whole Body is surrounded with such an Infection, wherein the noxious Particles floating about on all Sides, will endeavour to penetrate through the Pores upon the Surface, and get that Way into the Blood; for although the Skin is thicker upon the Surface of the Body, than that Pellicle covering the Vessels in the Lungs, and for that Reason it requires longer Time for such Particles to get that Way into the Blood, and the Habit of the Body, yet it is no Argument that they cannot get that Way at all, and be admitted into the Juices."
BY this we are able to gather, that when a Fever from some Faults in the _Non-naturals_ comes to the highest Degree of Malignity, it makes such a Change in the animal Fluids as renders some Parts of them poisonous, and capable of exciting the like fermentative Motions, wheresoever they come into a proper Subject, without any of those procatarctic Causes as gave Rise to the Fever of the first Person seized.
OF what Nature then this Poison is we may conjecture from the Circ.u.mstances of its Production. All animal Bodies do more or less generate a Salt; or rather, in Proportion to the Strength of their digestive Powers, do they more or less subtilize the saline Particles which are taken in with their necessary Nourishment. This is abundantly manifest in the Distillation of many animal Substances, which plentifully yield a volatile Salt. But indeed in the Composition of this, in a natural and healthful State, there is joined a very subtilized Sulphur or Oil; which contempers and softens it into a Fitness for the Purposes of the OEconomy: And under this Modification, it becomes the Principle of Vitality, and the chief Instrument of animal Action; not unlike what this is conceived to be, is the common _Sal volatile oleosum_, or any other Spirits drawn from odorous Bodies.
IT matters not what Names Persons please to distinguish this by, in an humane Body; but that somewhat of this Kind is naturally the Produce of its digestive Powers, in the highest Degree of Comminution or Subtilization they are capable of bringing any Thing to, no one will question; and that those minute Threads or Fibres, of which the whole is a Composition, are animated by it; or, to speak more strictly, owe to it their Elasticity and motive Faculties.
IT is hoped, that no one who hath been accustomed to Reasonings of this Nature, will find any Difficulty in conceiving such a Difference of Principles, so finely blended together, as here suggested of a saline, and an oleous, or humid Substance: And whosoever reads _Bellini_, or any others who have wrote in the same Manner, will find continual Regard had to those two Principles, even in the animal Spirits; for without it there can be no Notion had of what is so frequently mentioned, and which by their Effects we find must be true of them, that they are too dry, hot, active, fiery, and the like; or too humid, vapid, sluggish, viscid, _&c._ And it is further equally manifest, that in Proportion to the greater or lesser Degrees of Motion in those Fluids, from whence this subtile Composition is generated, and the Concussions of those fine Threads into which it is separated, will it err in one or other of the foregoing Extremes.
IN a Fever therefore, where the animal Fluids are in the highest Degree of Agitation, and from Causes too of a coagulating Nature, it ought to be no Wonder that even this subtile Union should be in some Measure dissolved, and the softer and more humid Parts broke and exhaled, so much as to leave the more rigid and saline ones not only unfit to lubricate those Elastick Threads, wherein they reside, but sharp and pointed enough to stimulate, contract, and harden them into all Loss of Motion.
AS the Destruction likewise of this _Nexus_ in so subtile a Fluid leaves the saline Parts capable of injuring even that OEconomy which gave it Existence, so may its Volatility favour its Escape in a great Measure by Transpiration, so as to affect also other Persons within its Reach; and These with all other Particles of like Nature, which, by an Over-Agitation, and fermentative Motion of the animal Fluids, are separated from the softer and lubricating Compositions with which they were naturally joined, and which by their Volatility transpire and float in the Air, we take to be the true _contagious Miasmata_, that convey, propagate, and continue a _Pestilence_, after the Cause first raising it ceases.
NOR will this seem strange to any who are accustomed to reflect, how many Substances are changeable into a poisonous Nature, which before were not only inoffensive, but useful to the Purposes of Life. Some Minerals, whose saline Parts in their Production are naturally blended with good Quant.i.ties of Sulphur, are harmless, and good _Alterants_; but when by any Means those Principles are separated, the saline Parts become strong _Emeticks_ and _Catharticks_, even to the Degree of a Poison. Who does not know that _Antimony_ may be taken crude in large Quant.i.ties without any manifest Effect, but that the Chymist can take somewhat from it, that in few Grains shall operate beyond the Power of a strong Const.i.tution to bear?
THOSE Arrows of Death therefore that make such dreadful Slaughter in a _Contagion_, are the animal Salts of infected Persons, set loose from their natural Combinations, and subtilized into the highest Degree of Volatility, by the Agitation and fermentative Motion of a Fever. And the Buboes, Carbuncles, _&c._ in a _Pestilence_, are nothing else but Collections of Particles, or Coalescences, formed in such irregular Motions, and thrown out of the Course of Circulation by those necessary Laws whereby every Thing is rejected, that cannot be a.s.similated into h.o.m.ogeneous and like Properties: The Matter of which Excretions is likewise of so subtile and fermenting a Nature, that if introduced into the Fluids of another well Person, it excites there the same Motion and Disorder.
THIS change of animal Substances into a Poison, is too common a Truth to want any Attestation to those who have been but indifferently conversant in Natural Enquiries. And it is greatly to our Purpose, that even those Creatures, which are generally deemed poisonous, do require certain Degrees of Heat, and animal Action, to exalt their Juices to so high a Degree of Volatility, as to put on the Properties of a Poison, and act as such upon other living Creatures; insomuch that it is not only a common Observation that these Animals lose their poisonous Nature when remov"d into Climes colder than what is natural to them, but that also they are not so venomous in their own Climates, at the cooler Seasons of the Year, as in the most sultry.
BUT the Case of a mad Dog entirely comes up to that of a _Contagion_ from a Fever. When the hotter Seasons of the Year throw that Creature into Madness, it is manifestly from a great Increase of Velocity and Motion in the Fluids, which brings on what is equivalent to a _Delirium_, by an additional _Impetus_ upon the Brain, and for want of so much Room through the Skin for Transpiration, as in other Animals; the chief Evacuation is by the Glands of the Mouth: That is, in short, the Dog hath a Fever, which breaks the natural Texture of the Juices, disengages and subtilizes the more rigid or saline Parts, and critically discharges them by the most convenient Outlets the Creature is furnished with, changed into such a poisonous Nature, that wheresoever they come to mix with the Juices of others, they excite in them the like inordinate and mischievous Alterations.
THIS Theory likewise might be further ill.u.s.trated by many Instances from inanimated Fluids, which are capable of being put into Fermentation by a very small Portion of Matter, and which shall by such an Agitation from new Particles, or _Moleculae_ having Properties of communicating the same Effects to another quiescent Fluid; not much unlike what we see in the Communication and Propagation of Fire, which is excited and carried on in proper Subjects from the minutest Beginnings, and increasing also in its own Force as it spreads.
WHEN a Person therefore falls into a Fever from any epidemic, or other more private Cause, and that Fever rises to such a Degree of Malignity as is always supposed in a _Pestilence_, as far as any _Effluvia_ do exhale from that Person, so far may he be said to have round him a contagious and poisonous _Atmosphere_; because there transpires from him such Particles as will excite in other Animals of like Const.i.tution, the same fermentative Motions as those to which they owe their own Origin.
ALTHOUGH therefore, in the Beginning of epidemical Diseases, and during the Subsistence of their common Causes, particular Regard is to be had to these Causes, and the Manner whereby they affect the People; yet when it is come to this pa.s.s, that the Fever it self is productive of a Poison, or somewhat intirely disagreeable, that communicates the same Impressions upon others, without any Concurrence of the first Cause, then such a Fever is truly a Pestilence by Contagion, and all precautionary Regards ought peculiarly to be suited, to prevent its Infection or Spreading; either by keeping the well Subjects clear from the sick, or destroying the Influence of the poisonous Exhalations, or fortifying the sound against it. But to these Ends, it is necessary to have some tolerable Notion of the Manner how these secret Destroyers are continued, and conveyed to great Distances.
THE most common Manner of conveying and spreading a Contagion, observable in the preceding historical Collections, and which also is the Case of our present Apprehensions from Abroad, is by infected Persons, and Merchandize; it being attested by too many Facts to admit of the least Doubt, that even Packs and Bails of Goods carry the poisonous _Miasmata_ about with them; and from the Nature that we here suppose this Poison to be of, nothing is more likely to preserve it than animal Substances, as Hair, Wool, Leather, Skins, _&c._ because the very Manner of its Production, and the Nature of its Origin, seems to give it a greater Affinity with such Substances than any other, and to dispose it to rest therein until by Warmth, or any other Means of Dislodgement, it is put into Motion, and raised again into the ambient Air.
TO know how these _Effluvia_ come to have such fatal Influences over Mankind, and to understand their Progression from the first Seizure, to the End of that Distemper they gave Birth to, requires too many _Precognita_ from the Mechanism of the animal OEconomy, and the Agency of such minute Instruments, to be particular about, in the Compa.s.s here limited. And a Reader who is duly fitted for such Enquiries, will find the utmost Satisfaction from _Bellini_ of _Fevers_, and Dr. _Mead_ of _Poisons_; how the Blood, and all the Secretions therefrom, are affected, and changed by such Causes.
WE shall here therefore only suggest some Hints concerning the Suddenness of their Seizure, and their Energy of Operation. And this will not be difficult to conceive by those who are acquainted with that universal Property of Matter, whereby it is more or less determined to draw, and unite again, when separated into Parcels, according to the greater or lesser Affinities of their Figures, Solidities, and Quant.i.ties of Motion.
As nothing therefore in Nature is supposed to bear a greater Similitude, than in this Case the natural animal Salts do with what hath been subtilized and set on Float in the Air, it can be no Wonder that when the Ambient is sated with the latter, they readily join with the former, as soon as they are received into the Body. And this is supported by the Authority even of _Bellini_, who allows, in the Beginning of his XXVIII_th Proposition_, that the _Antecedents_ to a pestilential Fever do sometimes vitiate the Spirits immediately in Quality.
AS the ordinary Course therefore of producing Fevers is by disordering the Blood first in Quality, with such Mixtures as coagulate it, that is, as make it unequally fluid, some Parts being thinner, and others thicker than natural; so by these extreamly subtile _Effluvia_, in a _Contagion_, the Spirits are destroyed in their natural Texture, and the more rigid and saline Parts, by a Combination with the venomous _Spicula_, changed into Dispositions destructive of that Const.i.tution they were before destined to preserve. Whosoever then considers what must be the necessary Consequences of such an immediate Depravation and Change in that Fluid, which is an absolute Requisite to all animal Action, will not at all wonder at any of the Affections which are commonly enumerated as the _Concomitants_ of a Contagion; and a tolerable Acquaintance with the OEconomy, by the Help especially of the Authors before referred to on _Fevers_ and _Poisons_, will enable any one to account severally for their Production.
THIS then being the Case of a _Contagion_, that a Person having a Fever, critically throws off poisonous _Effluvia_, which were generated during such irregular Motions of the animal Fluids, insomuch as to diffuse for some Distance round, what will infect other Persons within their reach; and that so many have got this Infection, that no Part of the Air, for some Tract of the Country together, is free from them; the poisonous _Atmospheres_, if they may be so termed, of the infected, extending and mixing into one universal, common _Contagion_; this, I say, being the Case here under Examination, why any at all survive, must be owing either to the Goodness of their Const.i.tution, or to proper Means to defend against its Infection, or to conquer it when received; which naturally brings us to consider these two important Ends, of _Preservation_ and _Cure_.
AS for the _First_ of these, the common Experience, of meaner People being mostly carried off, admonishes all to live upon as nutritive and generous a Diet as can be procured; and such Things as not only yeild due Nourishment, but Plenty of Spirits, and what easily perspires. For there are many Things of good Nourishment, that are not easily perspired; such as all light and viscid Substances, as Pork, Fish, and the like, which therefore are very apt to go into Fermentation, and generate Corruption; in short, whatever even the common People have Notions of, as apt to bring Surfeits, ought to be avoided, and such Means of Subsistance complied with, as generate a warm, rich Blood; and in Proportion to the Ways of Living at other Times, should every one, except those who accustom themselves to Riot and Excess, indulge himself at a higher Rate.
ROASTED Meats are by all preferred to boiled, and if Pickles and high Sauces are ever to be encouraged, it is on these Occasions; and _Garlick_, _Shallot_, _Onions_, &c. are extreamly serviceable, and preferable to the hot, dry, spicy Seasonings, because their pungent Volatility seems naturally covered with a Softness, or balsamick Quality, more agreeable to the Nature of animal Spirits. To which Purpose it is very remarkable, that in the Histories of many Pestilences, Notice is frequently taken of the Exemption of _Jews_, and People who deal much in such Fare, from Infection. And it is customary with some experienced Sailors, to lay in great Stores of such Things against their Arrival at infected, and unwholsome Countries.
THERE is also a very strict Regard to be had to the Firmness and Strength of the Solids, which is greatly a.s.sisted by moderate Exercises, but carefully avoiding too much, and every Thing that occasions too great an Expence of Spirits at a Time, and particularly by over-Warmth. But to this Purpose I cannot conceive any Thing more serviceable than frequent Immersion in cold Water, so that the Times of staying in are as short as possible, the Good received hereby being chiefly in the first Shudder and Constriction; and it is particularly to be remembred, tho" the preceding Author hath omitted it, that Watermen, and others, whose Occasions imployed them much upon the River, and in the Cold, suffered least in the late Sickness. The Use of _Vinegar_, and other _Acids_, are also of Service for the like Intention.
YET besides the Helps for this End from common Diet, and Way of Living, a.s.sistances may also be had from Medicinal Preservatives, such as those commonly termed _Antidotes_, consisting of spicy volatile Particles, which afford a natural _Pabulum_ to the animal Spirits, and by carrying into the whole Habit a fine subtle Oil, the better secure them against those Contagions _Spicula_ which are in Readiness to mix with them; and for this Purpose, we are furnished with a most elegant and useful Medicine, since many Authors of Note have wrote on this Subject, which is the _Sal Volatile Oleosum_, if it be well loaded with the essential Oils of Spicy Ingredients; although indeed with some Const.i.tutions more fetid Compositions are very suitable; but they all agree in carrying into the Habit somewhat that both recruits, and guards the Spirits against any foreign Mixture, or from unnatural Separations of their saline and humid Parts. And to the same End, in robust Const.i.tutions, who have been accustomed to fare hard, the Spirit or Oil of Turpentine frequently drank in small Doses might be a great Means to preserve the poorer Sort from Infection.