408 RUDIMENTAIJY, ATKOPUIED, Cii.vr. XIII. 



said to have been created " for the sake of synnnetry,'" or in 

 order " to complete the scheme of Nature." But this is not an 

 explanation, merely a restatement of the fact. Nor is it con- 

 sistent Avith itself : thus the boa-constrictor has rudiments of 

 hind-limbs and of a pelvis, and if it be said that these bones 

 have been n^taincd " to complete the scheme of Nature," why, 

 as Prof. Wcismann 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 astronomer who 

 niuintained 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 j)rescneo of rudimentary organs, by supposing 

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

 to the system ; but can we sujipose that the minute papilla, 

 Avhich often represents the pistil in male flowers, and wliich is 

 formed of mere cellular tissue, can thus act ? Can we suppose 

 that rudimentary teeth, which ai'e subsequently absorbed, are 

 beneficial to the rapidly-growing embryonic calf by removing 

 matter so precious as phosphate of lime ? When a man's fin- 

 gers have been amputated, imperfect nails have been known to 

 appear on the stumps, and I could as soon believe that these 

 vestiges of nails have been developed in order to excrete homy 

 matter, as that the rudimentary nails on the fin of the mana- 

 tee have been developed for this same purpose. 



On the view of descent Avith modification, the origin of 

 rudimentary organs is simple. We have plenty of cases of 

 rudimentary organs in our domestic productions — as the stump 

 of a tail in tailless breeds — the vestige of an ear in earless 

 breeds of sheep — the reappearance of minute dangling horns 

 in hornless breeds of cattle, more especially, according to 

 Youatt, in young animals — and the state of the whole flower 

 in the cauliflower. We often see rudiments of various parts 

 in monsters. But I doubt whether any of these cases throw 

 light on tlie origin of rudimentary organs in a state of nature, 

 further than by showing that rudiments can be produced ; for 

 I doubt whether species under Nature ever undergo- abrupt 

 changes. I believe that disuse has been the main agency ; 

 that it has led in successive generations to the gradual redut»- 

 tion of various organs, imtil tliey have become rudimentary — 

 as in the case of tlie eyes of animals inhabiting dark caverns, 

 and of the wings of birds iidiabiting oceanic islands, which 

 h:ive seldom be(Mi forced ])y l)e;ists of prey to take flight, and 



