December 1898] A THEORY OF RETROGRESSION 397 



theories which at present seem to hold the field — for instance, VVeis- 

 mann's theory of Germinal Selection, or Mr Francis Galton's theory 

 that so much of an individual is derived from this ancestor, so much 

 from that, and so much more from a third. Every one of these latter 

 theories ignores what seems to me the patent fact that the characters 

 of all the ancestors are not commingled in the final result, the 

 adult, but that during ontogeny each parent is represented in turn. 

 It is true that watching the development of an individual, we cannot 

 say that at such and such a point the great-grandparent ends and 

 the grandparent begins, that at this other point the grandparent 

 ends, and behold — the parent ! The changes are too complex and 

 subtle, too swift and fleeting ; moreover, at every turn the variations 

 from his ancestry of the individual under observation strike in and 

 add to the apparent confusion. 



It may be objected that the child during his development does 

 not represent exactly, nor even closely, any of his remote ancestors ; 

 and this objection would appear fatal to the above theory of heredity. 

 On the other hand any sufficient explanation of this vagueness of 

 representation will go far to establish, not only this theory, but also 

 that theory of retrogression which is the subject of this article, and 

 which — if it be a true theory — is in a humble way the complement 

 of the theory of evolution. 



Offspring, as we know, vary from their parents, and if they 

 vary, they must do so primarily in one of two ways. Either they 

 must revert to the ancestral type, and resemble it more than the 

 parent did, or else they must diverge from it still more than did 

 the parent. The former variation we term ' atavistic,' the latter we 

 may term ' evolutionary,' since it is on the lines of these latter varia- 

 tions that evolution proceeds. But of so-called atavistic variations, 

 there are also two kinds ; one of which is really atavistic or reversion- 

 ary, whereas the other, though apparently atavistic, is actually evolu- 

 tionary. True reversion occurs only when the individual varies so 

 from his parent that, in his development, he does not recapitulate 

 the whole of the life-history of his race, but stops short at a point 

 reached by a more or less remote ancestor, whom in this way he 

 resembles more than he does his parent. False atavism occurs when 

 the individual, at an early stage of his existence, begins by recapitu- 

 lating the whole of the life-history of his race up to his parent, but 

 during a later stage retraces, or apparently retraces, some of the last 

 steps made by himself in his development and by the race in its 

 evolution, and thus, by a species of evolutionary variation, resembles 

 a more or less remote ancestor more than he does the parent. 

 Kxamples of this false kind of atavism are plentiful in nature. 



The points here set forth are these. First, that development is 

 a recapitulation of evolution, in other words, that every individual 



