| → Saint Hilaire, as 1861 1866 1869 |
| Saint-Hilaire, 1872 |
|
| → lui." 1861 1866 1869 |
| lui." — — — — — — — — — — — — — — — — 1872 |
|
|
miraculous interposition. Lamarck seems to have been chiefly led to his conclusion on the gradual change of species, by the difficulty of distinguishing species and varieties, by the almost perfect
of forms in certain
groups, and by the analogy of domestic productions. With respect to the means of modification, he attributed something to the direct action of the physical conditions of life, something to the crossing of already existing forms, and much to use and disuse, that is, to the effects of habit. To this latter agency he seems to attribute all the beautiful adaptations in
as the long neck of the giraffe for browsing on the branches of trees. But he likewise believed in a law of progressive development; and as all the forms of life thus
to progress, in order to account for the existence at the present day of
simple productions, he
that such forms
now spontaneously
generated.
∗
|
|
| Geoffroy
→Saint Hilaire, as
stated in his 'Life,' written by his son, suspected, as early as 1795, that what we call species are various degenerations of the same type. It was not until 1828 that he published his conviction that the same forms have not been perpetuated since the origin of all things. Geoffroy seems to have relied chiefly on the conditions of life, or the
"
monde
as the cause of change. He was cautious in drawing conclusions, and did not believe that existing species are now undergoing modification; and, as his son adds,
un problème à réserver entièrement à l'avenir, supposé même que l'avenir doive avoir prise sur
→lui."
|
|
| In
Dr. W. C. Wells read before the Royal Society 'An Account of a White Female, part of whose
resembles that of a
but his paper was not published until his famous 'Two Essays upon Dew and Single Vision' appeared in 1818. In this paper he distinctly recognises the principle of natural selection, and this is the first recognition which has been indicated; but he applies it only to the races of man, and to certain characters alone. After
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