of the entrance of the plague into Rome in the year 1656, which we are affured was conveyed thither from Naples by cloths and other wares from that place, brought firft to Port Neptuno, and carried from thence to the neighbouring caftle of St Lawrence : which, after having been kept fome time there, were conveyed into Rome *. . The fecond inftance I fhall take is from the account given us of the entrance of the plague into Marseilles ; which being drawn up with great exactnefs, may be the more relied on. It appears indifputably by this account, that the mifchief was brought thither by goods from the Levant. For the first who had the diftemper, was one of the crew of the ship which brought thofe goods: the next were those who attended upon the fame goods, while they were under quarantine; and foon after the furgeon, whom the magiftrates of Marseilles appointed to examine the bodies of those who died. This relation, if duly confidered, is, I believe, fufficient to remove all the doubts any one can have about the power of merchandise to convey infection: for it affords all the evidence the moft fcrupulous can cafonably defire. Poffibly there might be fome fever of extraordinary malignity in Marieilles, fuch as is commonly called peftilential, before the arrival of thefe goods but no fuch fever has any indifputable right to the title of peftilence, as I have before fhewn. On the contrary, thefe two, the real pestilence, and fuch peftilential fevers, must carefully be diftinguished, if we defign to avoid all miftakes in reafoning upon thefe fubjects. : * Gataldi de peste, p. 116. s'eft paflé à Marieilles, &c. .. Journal de ce qui Some Some fuch fever of uncommon malignity, I fay, might perhaps be in Marfeilles before the arrival of thefe goods. There might likewife perhaps be an instance or two of fevers attended with eruptions, bear. ing fome refemblance to thofe of the plague: for fuch I myself have fometimes feen 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 fix weeks from the time of the failor's death, which had given the alarm, and raifed a general attention, before the magiftrates 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 fo long a truce in hot weather. The plague which has this prefent year almoft depopulated Meffina, affords a third inftance of the fame kind. By an authentic relation of it, publifhed here *, we are informed, that a Genoefe veffel from the Levant, arrived at that city; and upon notice given that a failor who had touched fome cafes of cot ton ftuffs bought up at Patraffo in the Morea, where the distemper then raged, was dead of the plague, in the voyage; the fhip was put under quarantine; during which time the cotton stuffs were privately landed. The mafter and fome failors dying three days after, the vessel was burnt. These goods lay for fome timé concealed, but were foon after publicly fold upon which the disease immediately broke out in that quar ter where they were opened; and afterwards was fpread through the whole city. : I think it not improper, for the fuller confirmation of the prefent point, to give a relation commu * Vid. the London gazette, July 23. 1743. nicated nicated to me by a perfon of unquestionable credit, of the like effect from goods, in respect to the fmallpox; which diftemper is frequently carried in the nature of the plague to both the East and West Indies from thefe countries, and was once carried from the Eaft Indies to the Cape of Good Hope, in the following manner. About the year 1718, a fhip from the Eaft Indies arrived at that place in the voyage three children had been fick of the fmall-pox: the foul linen ufed about them was put into a trunk and lockAt the ship's landing, this was taken out, and given to fome of the natives to be washed: upon handling the linen, they were immediately feized with the finall-pox, which spread into the country for many miles, and made fuch a defolation, that it was almost dispeopled. * It has been thought fo difficult to explain the manner how goods retain the feeds of contagion, that fome authors have imagined infection to be performed by the means of infects; the eggs of which may be conveyed from place to place, and make the difeafe when they come to be hatched. But as this is a fuppofition grounded upon no manner of obfervation, fo I think there is no need to have recourfe to it. If, as we have conjectured, the matter of contagion be an active fubftance generated chiefly from animal corruption, it is not hard to conceive how this may be lodged and preferved in foft porous bodies, which are kept preffed clofe together. We all know how long a time perfumes hold their fcent, if wrapt up in proper coverings: and it is ve ry remarkable, that the strongest of thefe, like the Kircher, Langius, &c. matter matter we are treating of, are mostly animal juices, as mufk, civet, &c. and that the fubftances found most fit to keep them in, are the very fame with those which are most apt to receive and communicate infection, as furs, feathers, filk, hair, wool, cotton, flax, &c. the greatest part of which are likewife of the animal kind. Nothing indeed can give us fo juft a notion of infection, and more clearly represent the manner of it, than odoriferous bodies. Some of these do strangely revive the animal fpirits; others inftantaneously deprefs and fink them: we may therefore conceive, that what active particles emitted from any fuch fubftances do, is in the like way done by peftiferous bodies; fo that contagion is no more than the effect of volatile offenfive matter drawn into the body by our finelling. The third caufe we affigned for the fpreading of contagion, was a corrupted state of air. Although the air be in a right state, yet a fick perfon may infect those who are very near him; as we find the peftilence to continue fometimes among the crew of a fhip, after they have failed out of the infectious air wherein the difeafe was firft caught. A remarkable accident of this nature is recorded to have happened in the plague at Genoa in the year 1656. perfons put to fea in a felucca, with defign to withdraw themselves from the contagion, and retire into Provence; but one of them falling fick of the plague foon after they had imbarked, infected. the reft; infomuch 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 Eleven that that time the boat arrived again at Genoa, no more than one of them furvived *. However, in this cafe the malady does not ufually fpread far, the contagious particles being foon difperfed and loft. But when in a corrupt difpofition of the air the contagious particles meet with the fubtile parts generated by that corruption, by uniting with them they become much more active and powerful, and likewise of a more durable nature; fo as to form an infectious matter capable of conveying the mischief to a greater distance from the difeafed body, out of which it was produced. But In general, a hot air is more difposed to spread contagion than a cold one, as no one can doubt, who confiders how much all kinds of effluvia are farther diffufed in a warm air, than in the contrary. moreover, that ftate of air, when unfeasonable moifture and want of winds are added to its heat, which gives birth to the plague in fome countries, will doubtless promote it in all. For Hippocrates fets down the fame description of a peftilential state of air in his country, as the Arabians do of the conftitution which gives rife to the plague in Africa †. Mercurialis affures us the fame conftitution of air attended the peftilence in his time at Padua : and Gaffendus obferved the fame in the plague of Digne ||. *Toulon, traité de la pefte. + Hippocr.. epid. 1. iii. That Hippocrates defcribes here the conftitution of air accompanying the true plague, contrary to what fome have thought, Galen teftifies in his comment upon this place, in libr. de temper. 1. i. c. 4. and in lib. de differentiis febr. lib. i. c. 4. Vid. Mercurial. prælect. de peftilent. Befides, |