AND ABORTED ORGANS. 469 



An organ, serving for two purposes, may become rudi- 

 mentary or utterly aborted for one, even the more impor- 

 tant purpose, and remain perfectly efficient for the other. 

 Thus, in plants, the office of the pistil is to allow the pollen- 

 tubes to reach the ovules within the ovarium. The pistil 

 consists of a stigma supported on a style; but in some Com- 

 positay, the male florets, which of course cannot be fecun- 

 dated, have a rudimentary pistil, for it is not crowned with 

 a stigma; but the style remains well developed and is 

 clothed in the usual manner with hairs, which serve to 

 brush the pollen out of the surrounding and conjoined 

 anthers. Again, an organ may become rudimentary for 

 its proper purpose, and be used for a distinct one: in cer- 

 tain fishes the swim-bladder seems to be rudimentarv for 

 its proper function of giving buoyancy, but has become 

 converted into a nascent breathing organ or lung. Many 

 similar instances could be given. 



Useful organs, however little they may be developed, 

 unless we have reason to suppose that they were formerly 

 more highly developed, ought not to be considered as 

 rudimentary. They may be in a nascent condition, and in 

 progress toward further development. Rudimentary 

 organs, on the other hand, are either quite useless, such as 

 teeth which never cut through the gums, or almost useless, 

 such as the wings of an ostrich, which serve merely as 

 sails. As organs in this condition would formerl}^ when still 

 less developed, have been of even less use than at present, 

 they cannot formerly have been produced through varia- 

 tion and natural selection, which acts solely by the preser- 

 vation of useful modifications. They have been partially 

 retained by the power of inheritance, and relate to a 

 former state of things. It is, however, often difficult to 

 distinguish between rudimentary and nascent organs; for 

 we can judge only b}^ analogy whether a part is capable of 

 further development, in which case alone it deserves to be 

 called nascent. Organs in this condition will always be 

 somewhat rare; for beings thus provided will commonly 

 have been supplanted by their successors with the same 

 organ in a more perfect state, and consequently will have 

 become long ago extinct. The wing of the penofuin is of 

 high service, acting as a fin; it may, therefore, represent 

 the nascent state of the wing: not that I believe this to be 



