To leave this Enquiry about Contagion to another Occasion, we will only observe, that this necessary Article is overseen and neglected by the Accurate Dr. Mead, for Reasons well known to himself, and easily to be guessed at by every body. It must be acknowledg’d that the Doctor’s way of writing and inquiring is very singular, the remaining part of his Book being carried on without Principles, or any known thing with which his Subject to be explained has any relation.
But, as I have now undertaken to make this short Discourse more intelligible, I will pursue my Design in Dr. Mead’s Method, as far as that does not obscure the Subject: In that Case I will take the Liberty to keep the Thread of our Discourse as much in our view is it is possible. Dr. Mead then having taken leave of Contagion, tells us, that this unknown Contagion is propagated by three Causes, The Air, diseased Persons, and Goods transported from infected Places. What a propagating Cause may be, shall be left to those that deal in Metaphysicks, to determine; it matters not what it appears to be, while the begetting Cause is unknown.
As to Air, he now undertakes to shew us how it becomes Infectious, and how it communicates its noxious Quality to other Bodies. The first, by the Authority of Hippocrates and Galen; but in this he mistakes his Authors, as he commonly does when they do not come up to his Purpose; for Hippocrates is thought, by many Authors, not to treat of the Plague, in this third Book of his Epidemicks; Galen, in the Commentary quoted by Dr. Mead, is so far from thinking that Hippocrates was resolved to give us Cases of the Plague, that he thought quite otherwise: And for the Truth of this Assertion, take an irrefragable Authority, instar omnium, the learned Dr. Friend, who says at the Remark [[1]]Λοιμωδης, hic non est proprie pestilens & contagiosus, siquidem in his morbis ab Hippocrate descriptis, nullum est contagii vestigium: Sed ut Galenus innuit aliud non est, quam Επιδημια ὀλέθριος. And a little after, sed ipse titulus Galeno paululum suspectus est.
We will not insist upon this Sense of Hippocrates; but suppose he there truly treats of the Plague, and that he has observed such a Temperament of Air to have preceded it, what is this to Contagion and Infection, which neither Hippocrates nor Galen ever dream’d of. Besides, Hippocrates calls the Plague a Fever, and in his Opinion several Affections of Air, to him, and us, perhaps, unknown, produced Plagues, or Fevers (for these Words are synonimous with him) and the greatest Part of other Diseases. So that it is manifest from Hippocrates, that this, and many other Alterations of the Air do not make it Infectious.
The following Paragraph is of no Force, after what is now said concerning Hippocrates; the best Historian, that is not a Physician, is never presumed to go beyond an Account and Relation of Matter of Fact, as he apprehends it; and so far went the great Thucydides, in relating the Plague of Athens. We will rather consider what the Doctor alledges for strengthning his Conjecture about Contagion. [[2]]Stinks of stagnating Waters, in hot Weather; putrid Exhalations from the Earth; and above all, the Corruption of dead Carcasses being unburied, have occasion’d infectious Diseases. Let us now suppose this Account to be true, yet his chief Article about Carcasses is absolutely false, as may be prov’d by one of the best Physicians in any Age; what is all this to Contagion breeding the Plague: For suppose again, some or all of them occasion’d infectious Diseases, the Consequence is not, Ergo, the Plague; there being many contagious Diseases that are neither Plague nor Mortal.
Yet, as if all this were Demonstration, he asserts, That the Plague is produced by a Concurrence of Causes; and their first Effect is a Degree of Stagnation in the Air, which is follow’d by Corruption, and Putrefaction. It is needless to enter upon this Hint of a new Hypothesis; for if his Machine of Contagion, or Infection, be good, these are unnecessary. But alas! the celebrated Doctor has, in the Conclusion, destroy’d the whole Fabrick he had rear’d with so much Trouble, after he had borrow’d Brick from one, Mortar from another, and Timber from a third; and only because he became, against Nature and his own Genius, a Master-Builder. Is a Concurrence of all the supposed Causes necessary to make a Plague? Then there never was a Plague in the World; and that because these Causes never all met together: A hopeful Conclusion! and which at once delivers the World of insufferable Fears, they hitherto groan’d under, by a vulgar Error; which is now contrary to Experience, because it is so to Dr. Mead’s Reasoning.
Hippocrates, on the other Hand, undertakes only to relate the Constitution of the Year when Plagues and Fevers were very frequent; he never thought of making any particular Constitution, or the Weather in it, the Cause of Plagues universally: If he had, Experience should have shewn the contrary, to which he would have submitted. But not to enter into any other Constitutions that might happen in Greece, Experience cries loudly against this Hypothesis of Dr. Mead; since we know that hard and continued frosty Weather produces the Pestilence, most commonly, in our Northern Climates. The Winter 1664, was a continued Frost all through, as Dr. Hodges informs us; yet the Plague broke out in the Christmas time, when it was in its Strength. The Plague in Dantzick, mention’d by Dr. Mead, was in the Winter, when every thing was bound up with a severe Frost; yet so violent was this Plague, that it bred the Dunkirk-Fever in the Fag-end of it, as Dr. Mead learnedly conjectures. So that the Pestilence frequently, and most commonly, happens in a Season very opposite to what the Doctor finds necessary for breeding Infection and Corruption, the Fore-runners of a Plague.
From all this Account it is manifest, that we hitherto know nothing of Contagion, nor of any Corruption convey’d into Air, which it is to foment and cherish, to beget or propagate the Pestilence; as also that this Notion of Contagion taken up and espoused by later Physicians, is very ill supported by them, and still worse by Dr. Mead, who is little acquainted with their Opinions, so common and obvious in Books of Physick. And therefore as he has been very unhappy in discovering the Change in Air that makes it infectious; we will try for better Success, in his discovering the Means, whereby it communicates its noxious Quality to other Bodies.
In order to pursue this Discourse with greater Exactness, it is necessary to ease our Memory from carrying the different Particulars of seven Pages, and not to oblige the Reader to take, on trust, what is writ so long before. It may, perhaps, be useful to Dr. Mead to tell us[[3]], that he, lately, left the Air in a putrid State; but that is nothing to us, who are at this present time sensible that the Doctor has not been able to bring the least Speck of Putrefaction into it. However, not to balk him in his projected Means, whereby it communicates its noxious Quality; he desires us to observe, that Putrefaction is a kind of Fermentation, and that all Bodies in a Ferment emit a volatile active Spirit, of Power to agitate, and put into intestine Motions, that is, to change the Nature of other Fluids, into which it insinuates it self. Now we have observed it, we find every Article of this Observation to be false; for Putrefaction does not always precede Fermentation, nor that every body in a Ferment emits volatile Spirits, nor that volatile Spirits have a Power to agitate, or to put into intestine Motions all Liquors into which they insinuate themselves; and still far less, that being put into intestine Motions, is to change the Nature of the Fluid thus put in Motion. What Use the Doctor may have for this Roll of precarious Assertions, time may tell us: for he has now got the Master-Key of all Philosophy, even Fermentation, into his Hand. By Fermentation Stones, Metals, Plants, Animals, and (if it pleases him) the Pestilence, are generated, and cherished. This makes Diseases; this cures them; by this we live, by this we die.
Neither does this Machine only answer all our Wants in performing the greater, but even the smaller feats, as we chance to employ it: for if we are asked, why Glow-birds shine in the Night? or why wet Hay takes Fire of it self, &c. one short Answer is sufficient to all these, that these great Works are done by Fermentation. A Poet in ancient times, pronounced those Nations happy, that had their rural Gods growing in their Gardens. But I esteem the Man far more happy, who has at hand so ready an Answer to every thing: who has got a Machine equally serviceable on every occasion, the Philosopher’s Stone, the universal Medicine, the making a Plague.