[153] Krause, The Scientific Works of Erasmus Darwin, footnote on p. 134: “See ‘Athenæum,’ March, 1875, p. 423.”
[154] Zoonomia, i., p. 505 (3d edition, p. 335).
[155] The subject of protective mimicry is more explicitly stated by Dr. Darwin in his earlier book, The Loves of the Plants, and, as Krause states, though Rösel von Rosenhof in his Insekten-Belustigungen (Nurnberg, 1746) describes the resemblance which geometric caterpillars, and also certain moths when in repose, present to dry twigs, and thus conceal themselves, “this group of phenomena seems to have been first regarded from a more general point of view by Dr. Darwin.”
[156] Zoonomia, vol. i., p. 170.
[157] Mr. Samuel Butler, in his Evolution, Old and New, taking it for granted that Lamarck was “a partisan of immutability till 1801,” intimates that “the secret of this sudden conversion must be found in a French translation by M. Deleuze of Dr. Darwin’s poem, The Loves of the Plants, which appeared in 1800. Lamarck—the most eminent botanist of his time—was sure to have heard of and seen this, and would probably know the translator, who would be able to give him a fair idea of the Zoonomia” (p. 258).
But this notion seems disproved by the fact that Lamarck delivered his famous lecture, published in 1801, during the last of April or in the first half of May, 1800. The views then presented must have been formed in his mind at least for some time—perhaps a year or more—previous, and were the result of no sudden inspiration, least of all from any information given him by Deleuze, whom he probably never met. If Lamarck had actually seen and read the Zoonomia he would have been manly enough to have given him credit for any novel ideas. Besides that, as we have already seen, the internal evidence shows that Lamarck’s views were in some important points entirely different from those of Erasmus Darwin, and were conceptions original with the French zoölogist.
Krause in his excellent essay on the scientific works of Erasmus Darwin (1879) refers to Lamarck as “evidently a disciple of Darwin,” stating that Lamarck worked out “in all directions” Erasmus Darwin’s principles of “will and active efforts” (p. 212).
CHAPTER XV
WHEN DID LAMARCK CHANGE HIS VIEWS REGARDING THE MUTABILITY OF SPECIES?
Lamarck’s mind was essentially philosophical. He was given to inquiring into the causes and origin of things. When thirty-two years old he wrote his “Researches on the Causes of the Principal Physical Facts,” though this work did not appear from the press until 1794, when he was fifty years of age. In this treatise he inquires into the origin of compounds and of minerals; also he conceived that all the rocks as well as all chemical compounds and minerals originated from organic life. These inquiries were reiterated in his “Memoirs on Physics and Natural History,” which appeared in 1797, when he was fifty-three years old.