ACTION OF THE FEMALE. 



to that which has been mingled with the prostatic fluid, yet it seems that this 

 inferiority simply results from its state of too great concentration, and not from 

 any endowments peculiar to the prostatic fluid, since dilution with other fluids 

 answers the same purpose. Mr. Newport's most recent observations upon the 

 process of impregnation in the Frog (which the Author, through the kindness 

 of Mr. N., has had the opportunity of verifying) show that the spermatozoa 

 become imbedded in the gelatinous envelop of the ovum, within a few seconds 

 after they come into contact with it, and that they are thus brought into close 

 approximation with (if they do not absolutely pass through) the vitelline mem- 

 brane ; in this situation they probably undergo a gradual diffluence ; and thus 

 the product of the " sperm-cell" may be absorbed into the " germ-cell," and 

 may intermingle with its contents, just as in the fecundation of the ovule of 

 Flowering-plants ; the Spermatozoon being nothing else than an embodiment of 

 the fertilizing material developed within the sperm-cell, which is endowed with 

 a temporary power of movement in order that it may find its way to the Ovum. 

 It has been remarked by Mr. Newport that Spermatozoa whose spontaneous 

 moft'foVy has ceased, no longer possesses the fecundating power; and this fact 

 concurs with other phenomena to indicate that it is not only a certain material, 

 but a vital force of which that material is (so to speak) the vehicle, which is 

 required to effect this most important operation. 



974. The precise share which the Germinal Vesicle and Germinal Spot per- 

 form in the changes which take place in the ovum about the period of fecunda- 

 tion, has not yet been satisfactorily determined. According to Dr. Barry, the 

 germinal vesicle becomes filled with a new development of cells, which sprout, 

 as it were, from its nucleus (the germinal spot) : and after fecundation a pair of 

 cells is seen in the space previously occupied by the pellucid centre of the nucleus 

 which is developed at the expense of the rest, and is the true foundation of the 

 embryonic structure. This view is to a certain extent confirmed by the observa- 

 tions of Wagner on the ova both of Frogs and Mammalia, and by those of Vogt 

 on those of the Rana obstetricans : both of which lead to the belief that such a 

 process of cell-formation does take place within the germinal vesicle, but that, 

 instead of the further development being carried on within the germinal vesicle, 

 as maintained by Dr. Barry, this ruptures and sets free the cells that had been 

 developed in its interior, which are now dispersed through the yelk, whose ulte- 

 rior changes take place under their influence. Mr. Newport's view is nearly 

 the same as this; and he states that, in the Frog, this dissolution of the germinal 

 vesicle and diffusion of its contents take place as a preparation for fecundation, 

 and not in consequence of it. 1 That the germinal vesicle is no longer to be seen 

 when the metamorphoses of the yelk have commenced, is now universally ad- 

 mitted; but with regard to the antecedent process just described, there is still a 

 want of accordance amongst Embryologists, its existence being altogether denied 

 by Bischoff, who maintains that the germinal vesicle simply dissolves away 

 shortly after coition, as had been supposed by Dr. Barry's predecessors. The 

 Author is strongly inclined to believe, however, from his own observations, as 

 well as from a priori considerations, based on the history of Vegetable fertiliza- 

 tion, that there is a development of cells within the germinal vesicle, at the time 

 of its maturation ; and that it is by the influence of the spermatic fluid upon one 

 of these cells, after it has been set free in the midst of the yelk by the rupture 

 or diffluence of the germinal vesicle, that the first cell of the embryonic fabric 

 is generated. 



975. Whatever be the precise nature and history of the Fecundating process, 

 there can be no doubt that the properties of the germ depend upon conditions, 

 both material and dynamical, supplied by both parents. This is most obviously 



1 "Philosophical Transactions," 1851, p. 178. 



