d Sea, Egypt and the Mediterranean; and (2) by land to
northern India and Afghanistan, thence to Persia and central Asia, and
so to Russia. In the great invasions of Europe during the 19th century
it sometimes followed one route and sometimes the other. It was not till
1817 that the attention of European physicians was specially directed to
the disease by the outbreak of a violent epidemic of cholera at Jessore
in Bengal. This was followed by its rapid spread over a large portion of
British India, where it caused immense destruction of life both among
natives and Europeans. During the next three years cholera continued to
rage all over India, as well as in Ceylon and others of the Indian
islands. The disease now began to spread over a wider extent than
hitherto, invading China on the east and Persia on the west. In 1823 it
had extended into Asia Minor and Russia in Asia, and it continued to
advance steadily though slowly westwards, while at the same time fresh
epidemics were appearing at intervals in India. From this period up till
1830 no great extension of cholera took place, but in the latter year it
reappeared in Persia and along the shores of the Caspian Sea, and thence
entered Russia in Europe. Despite the strictest sanitary precautions,
the disease spread rapidly through that whole empire, causing great
mortality and exciting consternation everywhere. It ravaged the northern
and central parts of Europe, and spread onwards to England, appearing in
Sunderland in October 1831, and in London in January 1832, during which
year it continued to prevail in most cf the cities and large towns of
Great Britain and Ireland. The disease subsequently extended into
France, Spain and Italy, and crossing the Atlantic spread through North
and Central America. It had previously prevailed in Arabia, Turkey,
Egypt and the Nile district, and in 1835 it was general throughout North
Africa. Up till 1837 cholera continued to break out in various parts of
the continent of Europe, after which this epidemic disappeared, having
thus within twenty years visited a large portion of the world.

About the year 1841 another great epidemic of cholera appeared in India
and China, and soon began to extend in the direction traversed by the
former, but involving a still wider area. It entered Europe again in
1847, and spread through Russia and Germany on to England, and thence to
France, whence it passed to America, and subsequently appeared in the
West