9. a 9 



METAMOEPHOSES OF MAN 



when the doctrine of parthenogenesis first appeared, 

 and which have since been confirmed, demonstrate 

 that segmentation is a manifestation of the special 

 vitality of the ovum, and is not clue 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. 



t 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 



