t all the old and unproductive should be
killed. That determination was part of a system of legislation by
which, in that country, the society was protected against
superfluous and dependent members.[1037]

+336. Special exigencies of the civilized.+ Civilized men in certain
cases find themselves face to face with the primitive circumstances, and
experience the primeval necessity, which overrides the sentiments of
civilization, whatever may be the strength of the latter. Colonel
Fremont, in 1849, in a letter to his wife, tells how in crossing the
plains he and his comrades left the weak and dying members of their
party, one by one, to die in the snow, after lighting a little fire for
him.[1038] Many other such cases are known from oral narratives. The
question is not one of more or less humanity. It is a question of the
struggle for existence when at the limit of one of its conditions. Our
civilization ordinarily veils from us the fact that we are rivals and
enemies to each other in the competition of life. It is in such cases as
the one just mentioned, or in shipwrecks, that this fact becomes the
commanding one. The only alternative to the abandonment of one is the
loss of all. Abortion, infanticide, and the killing of the old began at
times when the competition of life was so direct and pitiless that it
left no room for kindly sentiment. The latter is a product of
civilization. It could be cultivated only by men for whom the struggle
for existence was so easy, and the competition of life so moderate, that
the severity was all taken out of them. Then there was a surplus and the
conditions of life were easy. The alternative was not murder or suicide.
Such a state of ease was reached by migration or by advance in the
arts,--in short, by greater command of man over nature. The fundamental
elements in the case were altered.

+337. How the mores were changed.+ Abortion, infanticide, and killing
the old are primary folkways which respond to hard facts of life in the
most direct and primitive manner. They are not blamed when they become
ruling customs which everybody observes. They rise into mores more
easily than other primitive usages because the superficial reasons for
believing that they are conducive to welfare appear so simple and
obvious. When a settled life took the place of a wandering life some
immediate reasons for these customs were removed. When peace took the
place of war with neighboring tribes other