4P Of the Cauje of a feftilence, oftner happens, in its accidental and ad- ventitious Impurities. SOMETIMES this univerfal Principle languishes and degenerates, and in its own productive Womb is tainted with fome- what pernicious to Vitality, and that natu- ral balfamick ConfHtution of Blood that fupports it j and as often as this is the Cafe, the whole Orders of living Beinss may look upon it as War declared againfr. them : But where any Alteration is made upon it by particular and fortuitous Caufes, it is generally from too much Humidity diluting it, as in immoderate and unfeafoii- able Rains, whence moift, crude, and un- wholfome Vapours exhale - 7 for every one knows how* much Humidity is a Promoter of Putrefaction •, whence come Swarms of Infecls, which is a certain Forerunner of a PefK- lence : It alfp fometimes happens, that this vital Spirit, which fo much delights in Drynefs, is almoft. quite extinguiihed by a rainy Seafon ^ in which Exigency, what Miferies may not Mankind expecl, when a fmall Change is of fo fatal Confe- quence? This is abundantly confirmed by the Experience of Marfhy Countries, where the Difeafes recurring every Year are very fatal,
