e leader told of the discovery of the
remains of the tribe of Pikipitanges, a once populous tribe of which a
chief, six women and two boys alone are left. The tribe had been almost
wiped out, Dr. Farabee reported, by an epidemic of _influenza_!

If the aborigines of the New World succumb to the diseases of the
European, it is not less true that the European succumbs to diseases
against which his race has not been selected. The deadliness of yellow
fever to Americans in the tropics, and the relative immunity of Negroes,
is familiar; so too is the frequently fatal result of the African
tropical fevers on the white man, while the natives suffer from them
much less, having been made more resistant by centuries of natural
selection.

This long discussion may now be summarized. We dealt with lethal
selection, that form of natural selection which operates by prematurely
killing off the less fit and leaving the more fit to survive and
reproduce their kind. It is of course understood that the word "fit" in
this connection does not necessarily mean morally or mentally superior,
but merely fit for the particular environment. In a community of
rascals, the greatest rascal might be the fittest to survive. In the
slums of a modern city the Jewish type, stringently selected through
centuries of ghetto life, is particularly fit to survive, although it
may not be the physical ideal of an anthropologist.

Two forms of lethal selection were distinguished, one depending on
starvation and the other on causes not connected with the food supply.
Direct starvation is not a factor of importance in the survival of most
races during most of the time at the present day so far as the civilized
portion of the world is concerned. But disease and the other lethal
factors not connected with the food-supply, through which natural
selection acts, are still of great importance. From a half to two-thirds
of all deaths are of a selective character, even under favorable
conditions.

It is also to be noted, however, that with the progress of medicine, and
the diminution of unfit material, this kind of natural selection will
tend to become less and less widespread. For a long time, natural
selection in man has probably done little to cause marked change in his
physical or mental characteristics. Man's interference has prevented. In
recent centuries natural selection has probably done no more on the
whole than keep the race where it was: it is to be feared