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Rh in Ireland and in Scotland. Subsequent epidemics have occurred in these countries on numerous occasions. The last epidemic period in the British Isles was from 1868 to 1873, when it prevailed in several of the larger cities of England as well as in Scotland. Upon the continent of Europe it has prevailed chiefly in Russia and in Germany, and the earliest reliable accounts only date back to the year 1833, when it first appeared at Odessa. In 1863 a widespread epidemic occurred in Russia, and in 1868 it prevailed extensively in Germany. It again prevailed in Germany in 1874 to 1872, and in 1878 to 1879. In North America its prevalence has been limited to a few outbreaks in seaport cities having commercial relations with infected localities in Europe. In 1844 it was brought to Philadelphia by emigrants sailing from Liverpool; in 1847 it was brought in the same way to New York and spread to some extent to neighboring towns; in 1869 it was again imported into Philadelphia, and during the two following years spread to a slight extent in this city and in the State of Pennsylvania.

If we may judge from past experience, the predisposing causes of relapsing fever are not sufficiently active in this country to give rise to a serious epidemic, even if cases of the disease should again be brought to our shores. In Egypt, in India, in China, and in the Oriental countries generally, the conditions favorable for the epidemic prevalence of this disease are more commonly met with, and there is evidence that it exists in some of these countries at the present day and has probably been endemic for a considerable period, especially in India. But it is only recently that the English physicians in India have recognized its presence, it having been confounded for many years with the widely prevalent malarial fevers of the country.

Smallpox, like typhus and relapsing fever, is transmitted by personal contagion, but the susceptibility to this disease is so general, independent of predisposing causes, that in the prevaccination period it had a wide diffusion, not only in the overcrowded tenements of the poor, but also in the dwellings of the rich and even in the palaces of kings. The writings of the distinguished Greek physician Galen, who was born about 130 ., indicate that he was acquainted with smallpox, but the origin of the disease is lost in the obscurity of the remote past. According to Hirsch, "the native foci of smallpox may be looked for in India and the countries of central Africa." It still prevails extensively in these countries, where vaccination is only practiced to a limited extent. In the years 1873 and 1874 the mortality from this disease in India is said to have been five hundred thousand. "On European soil the smallpox, up to the beginning of this century, or to the introduction of vaccination, had been one