Metamorphoses of man and the lower animals / by A. de Quatrefages ; translated by Henry Lawson.

Date:
1864
Catalogue details

Licence: Public Domain Mark

Credit: Metamorphoses of man and the lower animals / by A. de Quatrefages ; translated by Henry Lawson. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    when tlie doctrine of ]oarfhem genesis first appeared^ and wMcli liave since been confirmed_, demonstrate that segmentation is a manifestation of the special vitahty of the ovmn_, and is not due to the influence of the male element^ which only regulates the process. Hence it is difficult to admit Professor Owen^s special force^ at least in his acceptation of it. We may add_, that the accumulation of this force^ its deterioration and exhaustion^ are just so many hypotheses^ which are doubtless exceedingly ingenious^ but which are supported neither by direct observation nor by ex- periment.* On the contrary^ the fact that among Aphides_, agamic reproduction may be almost inde- finitely prolonged by the employment of artificial heat^ is decidedly in opposition to the English naturalist^s opinions.f * In support of his view, Professor Owen brings forward the fact that the crab's feet are not reproduced indiscriminately at all the joints, but only at those where a peculiar cellular tissue is found, which tissue he regards as a remnant of the germinal cellular mass still endowed with the prolific power. Without dwelling upon the resemblance of this explanation to that for which Bonnet was reproached, I may observe that it is deciding one question by an appeal to another, and that it is necessary, in the first instance, to prove that the character of this tissue is that which the author presumes it to be. Professor Owen asserts also that the hydra's buds are developed only at certain fixed points ; but Laurent, who devoted himself for many years to the study of this animal, proved that it has the power of budding from every portion of its body, somewhat like a plant whose adventitious buds appear in all parts of the bark, and for the same reason. f Every doctrine put forward by so distinguished a man as Professor Owen carries with it, for that reason alone, a certain amount of influence. This is why I have reproduced in detail the statements which, on the first appearance of these essays, I thought necessary to make in opposition to his views. As I have