RUDIMENTARY ORGANS. 85 



or of the agencies through which the modifications of plants are 

 wrought out. Suffice it to remark that the " law of use and disuse " 

 of organs explains the majority of such cases, by asserting that organs 

 become degraded when they are no longer found to be useful to the 

 economy of their possessors. The degradation of a part is to be 

 looked upon as subservient to the welfare of the animal or plant as a 

 whole, and thus comes to be related to the great law of adaptation in 

 nature which practically ordains that 



Whatever is, is right. 



The animal world presents us, however, with more obvious and 

 better marked examples of rudimentary organs than are exhibited by 

 the modifications of flowers conspicuous as many of these latter 

 instances undoubtedly are. Turning our attention first to lower life, 

 we find amongst insects some notable and instructive illustrations of 

 abortive organs, and also of the ways and means through which the 

 rudimentary conditions have been attained. In the beetle order, the 

 natural or common condition of the wings which in insects typically 

 number four is that whereby the first pair becomes converted into 

 hardened wing-cases, beneath which the hinder and useful wings are 

 concealed when at rest. Now, in some species of beetles we may 

 meet with certain individuals with normally developed wings ; whilst 

 in other individuals of the species we find the wings to be represented 

 by the merest rudiments, which lie concealed beneath wing- cases, the 

 latter being actually firmly and permanently united together. In such 

 a case the modification has been extreme, but there can be no doubt 

 that the ancestors of the beetles with modified wings possessed fully 

 developed appendages ; otherwise we must regard the order of nature 

 as being one long string of strange and incoherent paradoxes. Mr. 

 Darwin has given us some instructive hints regarding the modification 

 of beetles' wings and feet in his remarks on the effects of the use and 

 disuse of parts in the animal economy. Kirby, the famous authority 

 on entomology, long ago noted the fact that, in the males of many 

 of the dung-beetles, the front feet were habitually broken off. Mr. 

 Darwin confirms the observation of Kirby, and further says that in one 

 species (Onites apelles] the feet "are so habitually lost, that the insect 

 has been described as not having them." In the sacred beetle 

 (Ateuchus) of the Egyptians the tarsi are not developed at all. Mr. 

 Darwin remarks that necessarily we cannot, as yet, lay overmuch 

 stress upon the transmission of accidental mutilations from parent to 

 progeny, although, indeed, there is nothing improbable in the supposi- 

 tion; and, moreover, Brown-Sequard noted that, in the young of 

 guinea-pigs which had been operated upon, the mutilations were 

 reproduced. Epilepsy, artificially produced in these latter animals, is 

 inherited by their progeny. " Hence," says Darwin, " it will perhaps 



