Butthefatalsecurity，likethepredestinationoftheTurks，musthaveaidedtheprogressofthecontagion；andthosesalutaryprecautionstowhichEuropeisindebtedforhersafety，wereunknowntothegovernmentofJustinian。NorestraintswereimposedonthefreeandfrequentintercourseoftheRomanprovinces:fromPersiatoFrance，thenationsweremingledandinfectedbywarsandemigrations；andthepestilentialodorwhichlurksforyearsinabaleofcottonwasimported，bytheabuseoftrade，intothemostdistantregions。ThemodeofitspropagationisexplainedbytheremarkofProcopiushimself，thatitalwaysspreadfromthesea—coasttotheinlandcountry:themostsequesteredislandsandmountainsweresuccessivelyvisited；
theplaceswhichhadescapedthefuryofitsfirstpassagewerealoneexposedtothecontagionoftheensuingyear。Thewindsmightdiffusethatsubtilevenom；butunlesstheatmospherebepreviouslydisposedforitsreception，theplaguewouldsoonexpireinthecoldortemperateclimatesoftheearth。Suchwastheuniversalcorruptionoftheair，thatthepestilencewhichburstforthinthefifteenthyearofJustinianwasnotcheckedoralleviatedbyanydifferenceoftheseasons。Intime，itsfirstmalignitywasabatedanddispersed；thediseasealternatelylanguishedandrevived；butitwasnottilltheendofacalamitousperiodoffifty—twoyears，thatmankindrecoveredtheirhealth，ortheairresumeditspureandsalubriousquality。
Nofactshavebeenpreservedtosustainanaccount，orevenaconjecture，ofthenumbersthatperishedinthisextraordinarymortality。Ionlyfind，thatduringthreemonths，five，andatlengthten，thousandpersonsdiedeachdayatConstantinople；
thatmanycitiesoftheEastwereleftvacant，andthatinseveraldistrictsofItalytheharvestandthevintagewitheredontheground。Thetriplescourgeofwar，pestilence，andfamine，afflictedthesubjectsofJustinian；andhisreignisdisgracedbythevisibledecreaseofthehumanspecies，whichhasneverbeenrepairedinsomeofthefairestcountriesoftheglobe。^95
[Footnote93:MeadprovesthattheplagueiscontagiousfromThucydides，Lacretius，Aristotle，Galen，andcommonexperience，p。10—20；andherefutesPreface，p。2—13thecontraryopinionoftheFrenchphysicianswhovisitedMarseillesintheyear1720。Yettheseweretherecentandenlightenedspectatorsofaplaguewhich，inafewmonths，sweptaway50，000inhabitantssurlePestedeMarseille，Paris，1786ofacitythat，inthepresenthourofprosperityandtradecontainsnomorethen90，000