29: PHILOSOPHICAL TRANSACTIONS. [aNNO 1713. 



means of some morbid effluvia, with which it is impregnated, it also infects 

 and destroys mankind. 



The signs observed in the air, at the time when the plague rages, are very 

 evident ; and especially those that are observed in mankind themselves, will 

 easily evince the infection of the air. On Aug. the 11th, at noon, I first ob- 

 served a stinking mist, like a thick cloud, but of short duration ; but at 4 

 o'clock it returned from the north west, so very thick, that it perfectly darkened 

 the air, and hindered the sight. It was neither blue nor grey, as other com- 

 mon mists ; but of a blackish yellow, like the vapours that rise from the effer- 

 vescence of oil of vitriol with oil of tartar. After it had reached the middle of 

 the town towards the south east, it inclined westward, and there emitted a 

 violent stench. Another sign of an infected air was not, as may perhaps be 

 thought, only a vulgar fancy, but the careful observation of learned persons, 

 viz. That in the month of July the crows, daws, sparrows and other birds, 

 which at other times are to be seen here in the town and about the gardens in 

 vast numbers, were all fled, and none of them to be seen till Nov. The same 

 was observed of the storks and swallows likewise ; and I can positively affirm, 

 that I saw none of those birds all those 4 months. 



As to the effects on the people, I have said that the distemper began and in- 

 creased gradually, and lessened in like manner; but the middle was the worst, 

 and most violent: for at first the buboes were more common than the furuncles, 

 carbuncles and vibices : afterwards again the petechias were more common than 

 these; though during the whole time of the contagion, they were never wholly 

 separated, so as to appear sometimes one without the other: at last the petechiae 

 and carbuncles went off; but the buboes continued last of all. 



The buboes, which are to be reckoned the first of the external signs, lie very 

 deep in the skin, and are at the beginning hard, unmoveable and round; after- 

 wards they grow longer, and may be moved. Outwardly they do not look red, 

 till they are drawn and brought to maturity. They are generally found in the 

 groins, armpits, and about the neck. Most of them come with a very violent, 

 cutting and pricking pain, accompanied with heavy symptoms, as pain in the 

 head and back, shivering colds, interchanged with heat, anxieties, faintness, 

 and frequently also bilious vomitings. According to the degree of malignity, 

 the symptoms are more or less violent: sometimes they are very mild, and the 

 bubo proceeds without any great pain. 



Furuncles differ from the common buboes, as they appear mostly in the fleshy 

 parts, to the number of 5, 7> or Q on one body. They are sometimes red, 

 and swell to a greater height than the buboes : their pain is very violent, and 

 disturbs the patient's rest. The other symptoms are much the same as in 



