408 THE ORIGIN OF SPECIES 



the relations of the parts, more useful than the discovery of rudi- 

 ments. This is well shown in the drawings given by Owen of the 

 leg bones of the horse, ox and rhinoceros. 



It is an important fact that rudimentary organs, such as teeth 

 in the upper jaws of whales and ruminants, can often be detected 

 in the embryo, but afterward wholly disappear. It is also, I believe, 

 a universal rule, that a rudimentary part is of greater size in the 

 embryo relativdy to the adjoining parts, than in the adult; so 

 that the organ at this early age is less rudimentary, or even cannot 

 be said to be in any degree rudimentary. Hence rudimentary or- 

 gans in the adult are often said to have retained their embryonic 

 condition. 



I have now given the leading facts with respect to rudimentary 

 organs. In reflecting on them, every one must be struck with 

 astonishment; for the same reasoning power which tells us that 

 most parts and organs are exquisitely adapted for certain pur- 

 poses, tells us with equal plainness that these rudimentary or 

 atrophied organs are imperfect and useless. In works on natural 

 history, rudimentary organs are generally said to have been cre- 

 ated "for the sake of symmetry," or in order "to complete the 

 scheme of nature." But this is not an explanation, merely a re- 

 statement of the fact. Nor is it consistent with itself: thus the 

 boa-constrictor has rudiments of hind limbs and of a pelvis, and 

 if it be said that these bones have been retained "to complete the 

 scheme of nature," why, as Professor Weismann asks, have they 

 not been retained by other snakes, which do not possess even a 

 vestige of these same bones? What would be thought of an astron- 

 omer who maintained that the satellites revolve in elliptic courses 

 round their planets "for the sake of symmetry," because the 

 planets thus revolve round the sun? An eminent physiologist ac- 

 counts for the presence of rudimentary organs, by supposing that 

 they serve to excrete matter in excess, or matter injurious to the 

 system; but can we suppose that the minute papilla, which often 

 represents the pistil in male flowers, and which is formed of mere 

 cellular tissue, can thus act? Can we suppose that rudimentary 

 teeth, which are subsequently absorbed, are beneficial to the rap- 

 idly growing embryonic calf by removing matter so precious as 

 phosphate of lime? When a man's fingers have been amputated, 

 imperfect nails have been known to appear on the stumps, and I 

 could as soon believe that these vestiges of nails are developed in 

 order to excrete horny matter, as that the rudimentary nails on 

 the fin of the manatee have been developed for this same purpose. 



On the view of descent with modification, the origin of nidi- 



