IMPORTANCE OF PRECOCITY IN EVOLUTION 319 



character can ever be so evoked, which the germ does not potentially possess. 

 Nor, on the other hand, can any innate or inherent character grow out of a 

 germ, which is not evoked from it by the forces of the environment, though 

 in the prenatal stages of growth these are heat and nutrition only. Both 

 kinds of character therefore have a common origin in the interplay between 

 the forces resident in the germ and the incident forces of the environment, 

 and the difference is in the proportions in which these two elements are 

 combined, a proportion which time continually modifies. The later the 

 development occurs in the " ontogeny," or individual growth, the greater 

 is the share of the environment in the result. But as fast as it travels back 

 in the ontogeny by repeated precocity, it grows more and more by the force 

 of nature — that is, by the inherent powers of the germ— and the influence of 

 the environment is proportionally reduced. As to this backward travelling 

 more hereafter ; at present I must pursue the asserted conversion of acquired 

 into congenital characters. 



If anyone finds this difficult to accept, I would still ask him whether it 

 may not possibly be what has actually happened, in which case he must of 

 course endeavour to rearrange his ideas more in harmony with the facts. 

 So far as I see, there is no such difference between the processes of growth 

 of the two sets of characters, as to make the conversion of the one into the 

 other by slow degrees unthinkable. If we look at the individual, all his 

 characters really originate in the germ, and the environment does but evoke 

 their growth and normally modify only the later ones. On the other hand, 

 if we look at the course of evolution as a whole, it may fairly be said that all 

 characters have originated in the environment, and by continual accelera- 

 tion of growth and consequent precocity all but the more recent of them 

 have gradually become the properties of normal development, to be duly 

 manifested in every case where nothing happens to prevent them. That 

 such a conversion is thinkable and possible, I am confident ; but that it is 

 what in fact has happened, seems to me to be an opinion from which there is no 

 escape. 



It is important to notice that this conversion of characters would be 

 effected without any change of the germ except such as may be involved in 

 the postulated acceleration of its growth. Some change must no doubt 

 occur to ensure this result, but otherwise the succession of germs in a hne of 

 descent might remain unchanged from one generation to another. Not 

 that I assert for a moment that it does so. On the contrary, for the simple 

 reason that no two tilings ever were or can be exactly alike, every germ differs 

 from every other germ in every conceivable particular of its structure, 

 though it may be in an infinitesimal degree. And as some of the almost 

 infinitely numerous differences thus originated in the final developments of 

 the resulting organisms cannot fail to be more, and others less, favourable to 

 their possessors in the struggle for life, the former will inevitably tend to 

 perpetuation, and the latter to elimination, as Darwin and Wallace were the 

 first to show. But the point is, that the modifications impressed on the body 

 by its converse \vith the environment are not transmitted from the structures 

 imrnediately involved to the germ-cells, so as to cause similar modifications in 

 the offspring subsequently arising from them, whether by means of Gemmules, 

 such as were postulated by Darwin's theory of Pangenesis, or in any other 

 way. No such apparatus is needed to bring about a mere acceleration of 

 growth in each generation, and I am fully convinced that Weismann was 

 right in contending for the essential independence of the germ-cells from the 

 " soma," or body, though of course each of these may, or rather must be and 

 is, variously affected by the presence of the other. And on the other hand 

 Spencer was abundantly right in contending for the cumulative effect of 

 environmental pressure upon an evolving race. But neither of them per- 

 ceived that it is by constantly repeated precocity that the accumulation 



