496 ORIGIN OF SPECIES 



which has become useless would be rendered, independently 

 of the effects of disuse, rudimentary and would at last be 

 wholly suppressed; for the variations towards diminished 

 size would no longer be checked by natural selection. The 

 principle of the economy of growth, explained in a former 

 chapter, by which the materials forming any part, if not 

 useful to the possessor, are saved as far as is possible, will 

 perhaps come into play iy rendering a useless part rudimen- 

 tary. But this principle will almost necessarily be confined 

 to the earlier stages of the process of reduction; for we can- 

 not suppose that a minute papilla, for instance, representing 

 in a male flower the pistil of the female flower, and formed 

 merely of cellular tissue, could be further reduced or ab- 

 sorbed for the sake of economising nutriment. 



Finally, as rudimentary organs, by whatever steps they 

 may have been degraded into their present useless condition, 

 are the record of a former state of things, and have been 

 retained solely through the power of inheritance, — we can 

 understand, on the genealogical view of classification, how it 

 is that systematists, in placing organisms in their proper 

 places in the natural system, have often found rudimentary 

 parts as useful as, or even sometimes more useful than, parts 

 of high physiological importance. Rudimentary organs may 

 be compared with the letters in a word, still retained in the 

 spelling, but become useless in the pronunciation, but which 

 serve as a clue for its derivation. On the view of descent 

 with modification, we may conclude that the existence of 

 organs in rudimentary, imperfect, and useless condition, or 

 quite aborted, far from presenting a strange difficulty, as 

 they assuredly do on the old doctrine of creation, might even 

 have been anticipated in accordance with the views here 

 explained. 



SUMMARY 



In this chapter I have attempted to show, that the arrange- 

 ment of all organic beings throughout all time in groups 

 under groups — that the nature of the relationships by which 

 all living and extinct organisms are united by complex, radi- 

 ating, and circuitous lines of affinities into a few grand 

 classes, — the rules followed and the difficulties encountered 



