RECAPITULATION 53 



unattended by regressive evolution, but, for the sake of 

 simplicity, we may first of all imagine an organ which has 

 evolved towards perfection by the uninterrupted accumulation 

 during generations of only such progressive variations as have 

 favoured evolution in a given direction. In other words, we 

 are imagining an organ which was a little better developed in 

 the son than in the father, in the father than in the grandfather, 

 and so on, in an uninterrupted series, right up to the ances- 

 tor in whom the organ had its beginnings. We are supposing 

 that, all through the long line, no individual occurred who 

 had not the organ a little better developed than his prede- 

 cessor. Now, since each individual of the line has recapitu- 

 lated the development of his predecessor, and at the end of 

 the recapitulation made a small addition of his own, which in 

 turn was recapitulated by his successor with yet another small 

 addition, it is clear that the last descendant must recapitulate 

 the organ as it was in each ancestor in turn, 1 beginning with 

 the first in whom the organ commenced, and ending with his 

 own addition to the organ as it was in his parent. By such 

 means, and such means only, can the organ develop in him. 

 In this way only, apart from acquirement, is growth possible. 

 Apply this reasoning to every organ in the body and we see 

 why the development of the individual is a recapitulation of 

 the life-history of the race. 



89. But every organ is made up of inter-dependent parts, 

 just as every individual is made up of inter-dependent parts 

 or organs ; and therefore an organ usually undergoes evolution 

 in several directions at once. Thus it may grow broader and 

 thicker as well as longer ; new structures may appear on or 

 in it; the relationships and comparative sizes of its parts 

 may be altered. Regressive changes may occur which may 

 coincide with, and be correlated to progressive changes in 

 other directions. Thus, while the penguin's fore-limb was 

 being altered from an organ of locomotion in the air to one 

 of locomotion in the water, much was being lost to the wing 

 at the same time that something was being gained. 



90. But through all these permutations and combinations, 

 through the apparent confusion of these progressions and 



1 This statement is liable to be misunderstood. At any rate it has 

 been misunderstood. It is not meant of course that an individual, when 

 he has finished the recapitulation of one ancestor, begins again at the 

 germ-cell and recapitulates the whole of the development of the next 

 ancestor. It is only meant that he recapitulates in orderly succession 

 the persistent additions made to the development by each successive 

 ancestor. 



