association, succeeds in partially destroying them. Their very
longevity would thus appear as a result of their social life.
Could we not say the same as regards their wonderful memory,
which also must be favoured in its development by society--life
and by longevity accompanied by a full enjoyment of bodily and
mental faculties till a very old age?

As seen from the above, the war of each against all is not
the law of nature. Mutual aid is as much a law of nature as
mutual struggle, and that law will become still more apparent
when we have analyzed some other associations of birds and those
of the mammalia. A few hints as to the importance of the law of
mutual aid for the evolution of the animal kingdom have already
been given in the preceding pages; but their purport will still
better appear when, after having given a few more illustrations,
we shall be enabled presently to draw therefrom our conclusions.

NOTES:

1. Origin of Species, chap. iii, p. 62 of first edition.

2. Nineteenth Century, Feb. 1888, p. 165.

3. Leaving aside the pre-Darwinian writers, like Toussenel, Fee,
and many others, several works containing many striking instances
of mutual aid--chiefly, however, illustrating animal
intelligence were issued previously to that date. I may mention
those of Houzeau, Les facultes etales des animaux, 2 vols.,
Brussels, 1872; L. Buchner's Aus dem Geistesleben der Thiere, 2nd
ed. in 1877; and Maximilian Perty's Ueber das Seelenleben der