400 NATURAL SCIENCE [December 
favourable individual of a species has been chosen and multiplied 
by means of slips, the rest of the species being eliminated ; and 
in each new seminal generation the process has been repeated. Such 
plants, therefore, have been evolved by a tremendously severe pro- 
cess of selection, resulting in an evolution much more rapid than is 
possible among animals or annual plants. But now supposing we 
chose any one of these highly divergent varieties, and without 
using any selection, bred from seed alone, what again would 
happen? There is ample evidence leading us to believe that in the 
vast majority of instances the variety would swiftly (that is, in a 
very few generations) revert to something very like the wild stock 
from which it originally descended, but not to the wild stock pre- 
cisely, for, no doubt, while the cultivated species was undergoing 
evolution in one direction, it was, under the changed conditions, 
undergoing retrogression in other particulars, and in these the reverted 
varieties would differ from the wild stock. 
I need not dwell longer on the tendency such plants and 
animals have towards retrogression. The facts are notorious. But 
it seems to me that these facts are strongly adverse to all those 
recent theories of heredity to which I have alluded, and which 
suppose that each ancestor is not represented in turn during the 
ontogeny, but that the characters of all or many of the ancestors 
are commingled or are latent in the final result, the adult—Weis- 
mann’s theory of germinal selection for instance, or Mr Galton’s 
theory, which supposes that, on the average, one quarter of the 
total heritage of an individual is derived from the parent, one- 
eighth from the grandparent, one-sixteenth from the great grand- 
parent, and so on. Were such theories true there could be no 
retrogression except through reversed selection, for the more evolved 
ancestors would for ever tend to make their influence felt. But 
plainly retrogression occurs in the mere absence of selection. 
Moreover, if it be true that the organic world has arisen through 
the preservation and accentuation of favourable variations, and if 
it also be true that ontogeny is a recapitulation of phylogeny, then 
it seems to me that it must be further true that there is necessarily 
a greater tendency towards retrogression than towards evolution. 
For all atavistic variations must tend towards retrogression ; where- 
as all evolutionary variations need not constitute extensions of 
the previous evolution. They may result in divergencies in new 
directions ; or may even constitute reversals of the previous evolu- 
tion, as in those cases of which Reversed Selection takes advantage. 
Given sufficient time, in the absence of selection, retrogression 
must therefore necessarily ensue. 
The rationale of retrogression, I take it, is as follows :— 
Suppose, as regards any character which has undergone evolution, 
