VARIATIONS, DUE TO REVERSION. 53 



very slowly. Even if an organ did suddenly disappear 

 in some one individual, by an arrest of development, 

 intercrossing with other individuals of the same species, 

 would cause it to reappear in a more or less perfect 

 manner, so that its final reduction could only be effected 

 by the slow process of continued disuse or natural selec- 

 tion. It is much more probable that, from changed 

 habits, of life, organs first become of less and less use, 

 and ultimately superfluous; or their place may be sup- 

 plied by some other organ; and then disuse, acting on 

 the offspring through inheritance at corresponding pe- 

 riods of life, would go on reducing the organ; but as 

 most organs could be of no use at an early embryonic 

 period, they would not be affected by disuse ; conse- 

 quently, they would be preserved at this stage of 

 growth, and would remain as rudiments." 



Again on page 353, Vol. ii, Animals and Plants, &c, 

 he says: 



" With domesticated animals, the reduction of a part, 

 from disuse, is never carried so far that a mere rudi- 

 ment is left; but we have good reason to believe that 

 this has often occurred under nature. * * * Struc- 

 tures which are rudimentary in the parent-species, be- 

 come partially re-developed in their domesticated prog- 

 eny. * * * They are of interest, as showing that 

 rudiments are the relics of organs once perfectly de- 

 veloped." 



"With Plants, the position of the flowers on the 

 axis, and of the seed in the capsules, sometimes leads, 

 through a freer flow of sap, to changes of structure ; 

 but these changes are often due to reversion." 



" Domesticated races, descended from the same spe- 

 cies, are liable to revert to characters derived from their 

 common progenitor." 



" Every one would wish to explain to himself, even 



