It appears that this terrific disorder had been raging for some time throughout the regions round the Mediterranean; having begun, as was believed, in Ethiopia--thence passing into Egypt and Libya, and overrunning a considerable portion of Asia under the Persian government. About sixteen years before, there had been a similar calamity in Rome and in various parts of Italy. Recently it had been felt in Lemnos and some other islands of the Aegean, yet seemingly not with such intensity as to excite much notice generally in the Grecian world: at length it passed to Athens, and first showed itself in the Piraeus. The progress of the disease was as rapid and destructive as its appearance had been sudden; while the extraordinary accumulation of people within the city and long walls, in consequence of the presence of the invaders in the country, was but too favorable to every form of contagion. Families crowded together in close cabins and places of temporary shelter--throughout a city constructed, like most of those in Greece, with little regard to the conditions of salubrity and in a state of mental chagrin from the forced abandonment and sacrifice of their properties in the country, transmitted the disorder with fatal facility from one to the other. Beginning as it did about the middle of April, the increasing heat of summer further aided the disorder, the symptoms of which, alike violent and sudden, made themselves the more remarked because the year was particularly exempt from maladies of every other description. Of this plague--or, more properly, eruptive typhoid fever, distinct from, yet analogous to, the smallpox--a description no less clear than impressive has been left by the historian Thucydides, himself not only a spectator but a sufferer. It is not one of the least of his merits, that his notice of the symptoms, given at so early a stage of medical science and observation, is such as to instruct the medical reader of the present age, and to enable the malady to be understood and identified. The observations with which that notice is ushered in deserve particular attention. "In respect to this distemper (he says), let every man, physician or not, say what he thinks respecting the source from whence it may probably have arisen, and respecting the causes which he deems sufficiently powerful to have produced so great a revolution. But I, having myself had the distemper, and having seen others suffering under it, will state _what it actually was_, and will indicate in addition such other matters as will furnish any man, who lays them to heart, with knowledge and the means of calculation beforehand, in case the same misfortune should ever occur again."