A Discourse on the Plague

by Richard Mead

I KNOW they imagine this their Sentiment to be abundantly confirmed from some Experiments made by Dr. Deidier[5] upon the Bile taken from Persons dead of the Plague: which having been either poured into a Wound made on purpose in different Dogs, or injected into their Veins, never failed, in many Trials, to produce in them all the Symptoms of the Pestilence, even the external ones of Bubo’s and Carbuncles. One Dog, upon which the Experiment succeeded, had been known, for three Months before, to devour greedily the corrupted Flesh of infected Persons, and Pledgets taken off from Pestilential Ulcers, without receiving any Injury. From hence they conclude[6] that this Disease is not communicated by Contagion, but originally bred in the Body by the Corruption of the Bile. This Corruption, they say, is the Effect of unwholsome Food; and the Bile thus corrupted produces a Thickness and a Degree of Coagulation in the Blood, which is the Cause of the Plague: Tho’ this they allow to be inforced by a bad Season of the Year, and the Terrors of Mind and Despair of the Inhabitants.

THESE Experiments are indeed curious, but fall very short of what they are brought to prove. The most that can be gathered from them is this: That Dogs do not, at least not so readily, receive Pestilential Infection from Men, as Men do from one another: And also, that the Bile is so highly corrupted in a Body infected with the Plague, that by putting it into the Blood of a Dog it will immediately breed the same Disease.

BUT it does not follow from hence, that the Bile is the Seat of the Disease, or that other Humors of the Body are not corrupted as well as this. I make no question but the whole Mass of Blood is, in this Case, in a State of Putrefaction; and consequently that all the Liquors derived from it partake of the Taint.

ACCORDINGLY it appeared afterwards from some Experiments made by Dr. Couzier[7], that not only the Blood, but even the Urine from an infected person, infused into the crural Vein of a Dog communicated the Plague. I will venture to affirm, that if, instead of Bile, Blood, or Urine, the Matter of the Ulcers had been put into a Wound made in the Dog; it would have had at least an equally pernicious Effect: As may well be concluded from the Inoculation of the Small Pox.

AS to the Dog’s eating the corrupted Flesh and purulent Matter of the Patients; it ought to have been considered that there are some Poisons very powerful when mixed immediately with the Blood, which will not operate in the Stomach at all: As in particular the Saliva of the mad Dog and the Venom of the Viper[8]. And therefore Dr. Deidier himself, some Months after his former Experiments, found that pestiferous Bile itself was swallowed by Dogs without any Harm[9].

THE right Inference to be made from these Experiments, I think, would have been this: That since the Blood and all the Humors are so greatly corrupted in the Plague, as that Dogs (tho’ not so liable to catch the Distemper in the ordinary way of Infection, as Men are) may receive it by a small Quantity of any of these from a diseased Subject being mixed with their Blood; it may well be supposed, that the Effluvia from an infected Person, drawn into the Body of one who is sound, may be pestiferous and productive of the like Disorder.

MY Assertion, that these French Physicians have before them the fullest Proofs of this Infection, not only appears from these Instances of it, I have observed to be recorded by themselves; but likewise from what Dr. le Moine and Dr. Bailly[10] have written, of the Manner in which the Plague was brought to Canourgue in the Gevaudan: as also from an amazing Instance they give us of the great Subtilty of this Poison, experienced at Marvejols: where no less than sixty Persons were at once infected in a Church, by one that came thither out of an infected House. The Plague was carried from Marseilles to Canourgue, as follows. A Gally-Slave, employed in burying the Dead at Marseilles, escaped from thence to the Village of St. Laurent de Rivedolt, a League distant from Correjac: where finding a Kinsman, who belonged to the latter Place, he presented him with a Waistcoat and a pair of Stockings he had brought along with him. The Kinsman returns to his Village, and dies in two or three Days; being followed soon after by three Children and their Mother. His Son, who lived at Canourgue, went from thence, in order to bury the Family; and, at his Return, gave to his Brother-in-law a Cloak he had brought with him: the Brother-in-law laying it upon his Bed, lost a little Child which lay with him, in one Day’s Time; and two Days after, his Wife; himself following in seven or eight. The Parents of this unhappy Family, taking Possession of the Goods of the Deceased, underwent the same Fate.

ALL this abundantly shews how inexcusable the foresaid Physicians in France are, in their opposing the common Opinion that the Plague is contagious. However, I have paid so much Regard to them, as to insist the more largely upon the Proof of that Contagion; lest the Opinion of those, who have had so much Experience of the Disease, might lead any one into an Error, in an Affair of such Consequence, that all my Precepts relating to Quarantaines, and well nigh every particular Part of my Advice, depends upon it: For if this Opinion were a Mistake, Quarantaines, and all the like Means of Defence, ought to be thrown aside as of no use. But as I continue persuaded, that we have the greatest Evidence, that the Plague is a contagious Disease; so I have left, without any Alteration, all my Directions in respect to Quarantaines: in which, I hope, I have not recommended any Thing prejudicial to Trade; my Advice being very little different from what has been long practised in all the trading Ports of Italy, and in other Places. Nay, were we to be more remiss in this than our Neighbours, I cannot think but the Fear they would have of us, must much obstruct our Commerce.

BUT I shall pursue this Point no farther: the rather because a very learned Physician among themselves has since, both by strong Reasoning and undeniable Instances, evinced the Reality of Contagion[11].

IN a word, the more I consider this Matter, the more I am convinced that the Precepts I have delivered, both with regard to the Preventing the Plague from coming into a Country, and the Treatment of it when present, are perfectly suitable to the Nature of the Distemper, and consequently the fittest to be complied with. But how far, in every Situation of Affairs, it is expedient to grant the Powers, requisite for putting all of them in Practice, it is not my proper Business, as a Physician, to determine. No doubt, but at all Times, these Powers ought to be so limited and restrained, that they may never endanger the Rights and Liberties of a People. Indeed, as I have had no other View than the Publick Good in this my Undertaking, and the Satisfaction of doing somewhat towards the Relief of Mankind, under the greatest of Calamities; so I should not, without the utmost Concern, see that any Thing of mine gave the least Countenance to Cruelty and Oppression.