172 CLUES AND SUGGESTIONS CHAP. 



fully admitted there is no antagonism 

 whatever between these general concep- 

 tions and the facts of Nature. 



The result of all these considerations 

 seems to be that when we meet with 

 structures in living animals, or bits of 

 structure, which have no function, we 

 never can be sure whether these repre- 

 sent organs which have degenerated or 

 organs which are waiting to be completed. 

 All that is certain is that they are parts 

 of the vertebrate Plan. That plan has 

 always implicitly contained, at every 

 stage in the history of organic life, 

 elements and tendencies of growth which 

 must have included both true rudiments 

 of the future, and also real vestiges of 

 the past. There is, indeed, one sup- 

 position which would put an end to our 

 search for organs on the way to use for 

 some future species and that is the 

 supposition that the development of new 



