256 METAMORPHOSES OF MAN 



them aside, and, with Huxley, frankly admit that 

 physiology is as yet too young to solve every enigma 

 which the Sphinx of science proposes. 



But although it is wise to abstain from explana- 

 tions which are evidently premature, still it is fair to 

 make some approach to an explanation, and that is 

 what I attempt to do. 



In the earlier portions of these essays, we saw that 

 among animals in which we have at present no reason 

 to suppose the existence of anything like partheno- 

 genesis, the unfecundated ovum demonstrates its own 

 special vitality by a series of movements quite analo- 

 gous to those which in the fecund ovum correspond to 

 the period of formation of the new being. We have seen 

 that in Hermella, Teredo, &c, this vitality is quickly 

 exhausted in proportion to its exertion. Now, conceive 

 of an ovum possessing a little more vital energy ; it 

 is evident that it will commence the process of organi- 

 zation. This is exactly what we find in by far the 

 greater number of eggs of the virgin female silk- 

 worm.* Let us in imagination increase this vital 

 power of the ovum, and we shall find it capable of 

 forming an embryo, which is quite perceptible, but 

 which will perish before it has been hatched. 



* In the course of my investigations into the nature of the disease 

 which committed such ravages among our silkworms, I had occa- 

 sion to open several cocoons containing female insects which had 

 never been set free ; most of them had deposited eggs, yet assuredly 

 in these instances it would be impossible to suppose the interven- 

 tion of the male. In most cases the ova had changed colour, and 

 had assumed the characteristic tints indicative of the organization 

 of the superficial strata of their contents. In very many instances 

 it was impossible to distinguish these ova from normal ones of the 

 same a^e. 



