d some four
hundred when the small-pox came and reduced them by one-fourth. Six
months later a woman developed tubercular consumption; the disease
spread like fire about the valley, and in less than a year two
survivors, a man and a woman, fled from the newly-created solitude....
Early in the year of my visit, for example, or late the year before, the
first case of phthisis appeared in a household of 17 persons, and by the
end of August, when the tale was told me, one soul survived, a boy who
had been absent at his schooling."

In Tasmania is another good illustration of the evolution of a race
proceeding so rapidly as to be fatal to the race. When the first
English settled on the island, in 1803, the native population consisted
of several thousand. Tuberculosis and many other new diseases, and, most
of all, alcohol, began to operate on the aborigines, who were attracted
to the settlements of the whites. In a quarter of a century there were
only a few hundred left. Many, of course, had met violent deaths, but an
enlightened perusal of any history of the period,[64] will leave no
doubt that natural selection by disease was responsible for most of the
mortality. By 1847 the number of native Tasmanians was reduced to 44,
who were already unmistakably doomed by alcohol and bacteria. When the
last full-blood Tasmanian died in 1876, a new chapter was written in the
story of the modern evolution of the human race.

No such stories are told about the white settlements on this continent,
even before the days of quarantine and scientific medicine. There is no
other adequate explanation of the difference, than that the two races
have evolved to a different degree in their resistance to these
diseases. It is easily seen, then, that man's evolution is going on, at
varying rates of speed, in probably all parts of the human race at the
present time.

We do not mean, of course, to suggest that all the natives who have died
in the New World since the landing of Columbus, have died because the
evolution of their race had not proceeded so far in certain directions
as had that of their conquerors. But the proportion of them who were
eliminated for that reason is certainly very large. In the more remote
parts of South America the process is still going on. Recent press
dispatches have carried the account of the University of Pennsylvania's
Amazon Expedition, under the direction of William C. Farrabee. In a
letter dated March 16, 1916, th