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 Thiere, Leipzig, 1876.  Espinas published his most remarkable work, Les Societes animales, in 1877, and in that work he pointed out the importance of animal societies, and their bearing upon the preservation of species, and entered upon a most valuable discussion of the origin of societies.  In fact, Espinas’s book contains all that has been written since upon mutual aid, and many good things besides.  If I nevertheless make a special mention of Kessler’s address, it is because he raised mutual aid to the height of a law much more important in evolution than the law of mutual struggle.  The same ideas were developed next year (in April 1881) by J. Lanessan in a lecture published in 1882 under this title:  La lutte pour l’existence et l’association pour la lutte.  G. Romanes’s capital work, Animal Intelligence, was issued in 1882, and followed next year by the Mental Evolution in Animals.  About the same time (1883), Buchner published another work, Liebe und Liebes-Leben in der Thierwelt, a second edition of which was issued in 1885.  The idea, as seen, was in the air.

4.  Memoirs (Trudy) of the St. Petersburg Society of Naturalists, vol. xi. 1880.

5.  George J. Romanes’s Animal Intelligence, 1st ed. p. 233.

6.  Pierre Huber’s Les fourmis indigees, Geneve, 1861; Forel’s Recherches sur les fourmis de la Suisse, Zurich, 1874, and J.T.  Moggridge’s Harvesting Ants and Trapdoor Spiders, London, 1873 and 1874, ought to be in the hands of every boy and girl.  See also:  Blanchard’s Metamorphoses des Insectes, Paris, 1868; J.H.  Fabre’s Souvenirs entomologiques, Paris, 1886; Ebrard’s Etudes des moeurs des fourmis, Geneve, 1864; Sir John Lubbock’s Ants, Bees, and Wasps, and so on.

7.  Forel’s Recherches, pp. 244, 275, 278.  Huber’s description of the process is admirable.  It also contains a hint as to the possible origin of the instinct (popular edition, pp. 158, 160).  See Appendix ii.