restraints were imposed on the free and frequent
intercourse of the Roman provinces: from Persia to France, the nations
were mingled and infected by wars and emigrations; and the pestilential
odor which lurks for years in a bale of cotton was imported, by
the abuse of trade, into the most distant regions. The mode of its
propagation is explained by the remark of Procopius himself, that
it always spread from the sea-coast to the inland country: the most
sequestered islands and mountains were successively visited; the places
which had escaped the fury of its first passage were alone exposed to
the contagion of the ensuing year. The winds might diffuse that
subtile venom; but unless the atmosphere be previously disposed for
its reception, the plague would soon expire in the cold or temperate
climates of the earth. Such was the universal corruption of the air,
that the pestilence which burst forth in the fifteenth year of Justinian
was not checked or alleviated by any difference of the seasons. In time,
its first malignity was abated and dispersed; the disease alternately
languished and revived; but it was not till the end of a calamitous
period of fifty-two years, that mankind recovered their health, or the
air resumed its pure and salubrious quality.

No facts have been preserved to sustain an account, or even a
conjecture, of the numbers that perished in this extraordinary
mortality. I only find, that during three months, five, and at length
ten, thousand persons died each day at Constantinople; that many cities
of the East were left vacant, and that in several districts of Italy the
harvest and the vintage withered on the ground. The triple scourge of
war, pestilence, and famine, afflicted the subjects of Justinian; and
his reign is disgraced by the visible decrease of the human species,
which has never been repaired in some of the fairest countries of the
globe. [95]

[Footnote 93: Mead proves that the plague is contagious from Thucydides,
Lacretius, Aristotle, Galen, and common experience, (p. 10--20;) and
he refutes (Preface, p. 2--13) the contrary opinion of the French
physicians who visited Marseilles in the year 1720. Yet these were the
recent and enlightened spectators of a plague which, in a few months,
swept away 50,000 inhabitants (sur le Peste de Marseille, Paris, 1786)
of a city that, in the present hour of prosperity and trade contains no
more then 90,000 souls, (Necker, sur les Finances, tom. i. p. 231.)