it was in 1827--that two little wren-fledglings, which had
run away from him, were found by him next day in the nest of
robin redbreasts (Rothkehlchen), which fed the little ones,
together with their own youngsters, Goethe grew quite excited
about this fact. He saw in it a confirmation of his pantheistic
views, and said:--"If it be true that this feeding of a
stranger goes through all Nature as something having the
character of a general law--then many an enigma would be
solved. "He returned to this matter on the next day, and most
earnestly entreated Eckermann (who was, as is known, a zoologist)
to make a special study of the subject, adding that he would
surely come "to quite invaluable treasuries of results"
(Gesprache, edition of 1848, vol. iii. pp. 219, 221).
Unfortunately, this study was never made, although it is very
possible that Brehm, who has accumulated in his works such rich
materials relative to mutual aid among animals, might have been
inspired by Goethe's remark.

Several works of importance were published in the years
1872-1886, dealing with the intelligence and the mental life of
animals (they are mentioned in a footnote in Chapter I of this
book), and three of them dealt more especially with the subject
under consideration; namely, Les Societes animales, by Espinas
(Paris, 1877); La Lutte pour l'existence et l'association pout la
lutte, a lecture by J.L. Lanessan (April 1881); and Louis
Buchner's book, Liebe und Liebes-Leben in der Thierwelt, of which
the first edition appeared in 1882 or 1883, and a second, much
enlarged, in 1885. But excellent though each of these works is,
they leave ample room for a work in which Mutual Aid would be
considered, not only as an argument in favour of a pre-human