An Expository Outline of the "Vestiges of the Natural History of Creation" - With a Notice of the Author's "Explanations:" A Sequel to the Vestiges by Anonymous
page 45 of 84 (53%)
page 45 of 84 (53%)
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assert, passes through a stage comparable or analogous to a permanent
condition of the same organ in any invertebrate animal; and in like manner the spinal cord in the human vertebræ at no period agrees with the corresponding part of the lower kind of animals. The moment it becomes visible in the human embryo, it is entirely dorsal in position; while in mollusks and articulatas a great part, or nearly the whole, is ventral. The same is true of the heart, or centre of the vascular system, which has always a different relative position in the great nervous centre in the human embryo from what it has in any articulate animal, and in most mollusks. A second position in the _Vestiges_ appears not to have been established--namely, as to the uniform geological arrangement of different organic structures. It is not true that _only_ the lowest forms of animal life are found in the lowest fossiliferous rocks, and that the more complicated structures are gradually and exclusively developed among the higher bands in what might be called a natural ascending scale. On the contrary, the predaceous cephalopods and the highly organized crustaceous are among the oldest fossils. Such appears to be the order of nature as evidenced by facts, and it must be admitted, however repugnant to preconceived notions or mere mortal conjectural amendments. In the third place the evidence seems to preponderate in favour of _permanency of species_. There can be no doubt that both plants and animals may, by the influence of breeding, and of external agents operating upon their constitution, be greatly modified, so as to give rise to varieties and races different from what before existed. But there are limits to such modifications, as in the different kind and breed of dogs; and no organized beings can, by the mere working of |
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