( III ) 
That the Air was infe£ed, during the Contagion here, 
is certain : Not that I mean a general Infe&ion, as if the 
Air was by a fupematural Power fo tainted and cor- 
rupted, as to taint and infeft all Things breathing $ 
for by this Means no Soul could have efcaped, and it 
would be too grofs a piece of Philofophy to advance ; 
But as it is a fubtile, moveable, and every where expanded 
Body, it attra&s and receives all Effluvia and Exhalati- 
ons, as a Spunge does. Water, and imparts them likewife 
(by means of its Motion) to other Bodies 5 fo that, as 
a communicative Medium, by the Entrance of it into our 
Bodies* we recieve whatever it carries along with it. I 
fhall therefore endeavour to explain how the Air comes 
to be of this or that Difpofition or Conftitution $ by 
what Means its pure and natural Temper is altered * 
and how far, and with what Particles it is impregnated ; 
for according to that it mud be more or lefs impure, and 
fo affett accordingly. 
It is generally obferved, that the Plague commonly 
enfues after great Battles. The Reafons alledged for it 
are, that the Exhalations proceeding from the vad Num° 
ber of Dead Bodies corrupt the Air, by which Mankind 
are afterwards infe&ed. How much more then mud 
they be infetted, when there is an a&ual Contagion 
mong them, notwithftanding that it ow’d its firft Rife 
to fuch Corruptions, as by means of the Air are brought 
from Foreign Parts ^ an Inftance of which we fee in 
Goods and Merchandizes. I fay,i the Infection of the 
Air mud be dill greater in proportion to the attual In- 
creafe of the Peftilence, when fo many thoufands of 
People die, and many continue to lye putrifying for 
many Days above Ground, and others are buried with** 
out a Coffin, and but a very little way under Gronnde 
Befides the Heat of the Weather (for thefe Cafualities 
generally happen in Summer) caufes the Bodies to cor- 
fooner ; 
