and other surroundings, but not to measles. That they suffered from sequelæ only proves how much the disease injured them. It certainly appears true that measles is a disease so mild that, in the great majority of instances, infected individuals, even of races that have had no experience of it, may be saved by proper treatment; but it is certainly true also, that individuals of such races are vastly less resistant to it than those of races which have long been afflicted by it—that they take the disease in its severer forms, and under unfavourable conditions succumb more easily.
"We all know the story of the measles in Fiji, how in 1876 it swept away forty thousand out of the population of one hundred and fifty thousand. Measles, when it attacks the Polynesians, is no longer the infantile malady we know of. It becomes a devastating plague. The Tongans, with the. experience of Fiji in their memories, took, it is true, some precautions against the after-effects of the disease; but nevertheless one-twentieth of the population was carried off, and the remainder was so demoralized that it was threatened with famine."—Thomson, The Diversions of a Prime Minister.
Dysentery, Diarrhoea, Enteric Fever, &c.—Malaria, tuberculosis, and measles afford ample proof that man's present evolution is mainly against disease, and moreover, that in different countries the direction of the evolution is different because different diseases differently determine it. Similar evidence is afforded by a study of many other diseases, for these, like malaria, tuberculosis, and measles, are invariably more fatal to strangers from beyond their areas of distribution than to races that have long dwelt within the districts they infest; but because few diseases are so prevalent within
