A HISTORY OF 



America, is said to be fatal ; as was that of the 

 juniper, if we may credit the ancients. Those 

 who walk through fields of poppies, or in any 

 manner prepare those flowers for making 

 opium, are very sensibly affected with the 

 drowsiness they occasion. A physician of 

 Mr. Boyle's acquaintance, causing a large 

 quantity of black hellebore to be pounded in 

 a mortar, most of the persons who were in 

 the room, and especially the person who 

 pounded it, were purged by it, and some of 

 them strongly. He also gathered a certain 

 plant in Ireland, which the person who beat 

 it in a mortar, and the physician who was 

 standing near, were eo strongly affected by, 

 that their hands and faces swelled to an enor- 

 mous size, and continued tumid for a long 

 time after. 



But neither mineral nor vegetable steams 

 are so dangerous to the constitution, as those 

 proceeding from animal substances, putrefying 

 either by disease or death. The effluvia that 

 come from diseased bodies, propagate that 

 frightful catalogue of disorders which are 

 called infectious. The parts which compose 

 vegetable vapours, and mineral exhalations, 

 seem gross and heavy, in comparison of these 

 volatile vapours, that go to great distances, 

 and have been described as spreading deso- 

 lation over the whole earth. They fly every 

 where ; penetrate every where ; and the va- 

 pours that fly from a single disease, soon ren- 

 der it epidemic. 



The plague is the first upon the list in this 

 class of human calamities. From whence 

 this scourge of man's presumption may have 

 its beginning, is not well known ; but we well 

 know that it is propagated by infection. What- 

 ever be the general state of the atmosphere, 

 we learn, from experience, that the noxious 

 vapours, though but singly introduced at first, 

 taint the air by degrees : every person in- 

 fected, tends to add to the growing malignity; 

 and, as the disorder becomes more general, 

 the putrescence of the air becomes more 

 noxious, so that the symptoms are aggravated 

 by continuance. When it is said that the 

 origin of this disorder is unknown, it implies, 

 that the air seems to be but little employed 

 in first producing it. There are some coun- 

 tries, even in the midst of Africa, that we 

 learn have never been infected with it ; but 



continue, for centuries, unmolested. On the 

 contrary, there are others, that are generally 

 visited once a year, as in Egypt, which, never- 

 theless, seems peculiarly blessed with the 

 serenity and temperature of its climate. In 

 the former countries, which are of vast extent, 

 and many of them very populous, every thing 

 should seem to dispose the air to make the 

 plague continual among them. The great 

 heats of the climate, the unwholesomeness 

 of the food, the sloth and dirt of the inhabi- 

 tants, but, above all, the bloody battles which 

 are continually fought among them, after 

 which heaps of dead bodies are left unburied, 

 and exposed to putrefaction. All these one 

 might think would be apt to bring the plague 

 among them ; and yet, nevertheless, we are 

 assured, by Leo Africanus, that in Numidia 

 the plague is not known once in a hundred 

 years ; and that in Negroland, it is not known 

 at all. This dreadful disorder, therefore, 

 must have its rise, not from any previous dis- 

 position of the air, but from some particular 

 cause, beginning with one individual, and 

 extending the malignity, by communication, 

 till at last the air becomes actually tainted 

 by the generality of the infection. 



The plague which spread itself over the 

 whole world, in the year 1346, as we are told 

 by Mezeray, was so contagious, that scarcely 

 a village, or even a house, escaped being in- 

 fected by it. Before it had reached Europe, 

 it had been for two years travelling from the 

 great kingdom of Cathay, where it began by 

 a vapour most horridly fetid ; this broke out 

 of the earth like a subterranean fire, and 

 upon the first instant of its eruption, consumed 

 and desolated above two hundred leagues of 

 that country, even to the trees and stones. 



In that great plague which desolated the 

 city of London, in the year 1665, a pious and 

 learned schoolmaster of Mr. Boyle's acquain- 

 tance, who ventured to stay in the city, and 

 took upon him the humane office of visiting 

 the sick and the dying, who had been de- 

 serted by better physicians, averred, that 

 being once called to a poor woman who had 

 buried her children of the plague, he found 

 the room where she lay so little that it 

 scarcely could hold any more than the bed 

 whereon she was stretched. However, in 

 this wretched abode, beside her, in an open 



