RELATIONS OF OVA AND GEMMJE. 205 



Such a view harmonizes with other results obtained by 

 Mr. Newport.* Thus he has observed that a deficiency 

 affecting one of the elements may be supplemented by an 

 increased action of the other, for he found that when the 

 spermatozoa were applied in a very concentrated form, even 

 immature ova became segmented and produced embryos. 

 Again he found that the procreative force both of the ova 

 and the spermatozoa was augmented by increase of heat, 

 but the duration of the force was lessened. Now, in the 

 primordial germs, that physiological law may well be sup- 

 posed to have full play, which appears even in the adult 

 state though there masked by the continual renewal of 

 the system, which it is the very object of its organization to 

 effect namely, that the endurance of vital action is in the 

 inverse ratio of its intensity. 



On the whole, after a careful survey of the part taken by 

 ova and gemmae respectively in the propagation of organic 

 beings, I think we can hardly avoid adopting Professor 

 Owen's conclusion, that there is no essential difference be- 

 tween the two, and that the one may pass into the other by 

 insensible gradations. It cannot at least be any longer 

 maintained as an invariable law though it is strongly con- 

 tended for by some that there is such an incompatibility 

 between these two modes of propagation, that in proportion 

 as any part of the parenchyma of the parent body is en- 

 gaged in the one course, it is in so far disabled for the other. 

 Such a statement, if admitted at all, must be held open to 

 many exceptions. We may assume perhaps, that, up to a 

 certain point, the development of the new focus of vital 

 action may go on all the same for a gemma or an ovum ; 

 but that towards the period of maturation the changes 

 which take place in the latter, to fit it for impregnation, 

 cause such a tension, as it were, of its vitality, as is incom- 



* Philos. Transac. (1851), pp. 206-209. 



