246 HOMOLOGIES. Chap. VIII. 



plan ; that he, therefore, made the same organ to per- 

 form diverse functions — often of trifling importance 

 compared with their proper function — converted other 

 organs into mere purposeless rudiments, and arranged 

 all as if they had to stand separate, and then made 

 them cohere ? Is it not a more simple and intelligible 

 view that all the Orchideae owe what they have in 

 common, to descent from some monocotyledonous 

 plant, which, like so many other plants of the same 

 class, possessed fifteen organs, arranged alternately 

 three within three in five whorls ; and that the now 

 wonderfully changed structure of the flower is due to 

 a long course of slow modification, — each modification 

 having been preserved which was useful to the plants 

 during the incessant changes to which the organic 

 and inorganic world has been exposed ? 



