CiiAr. IV. VARIOUS OBJECTlOiNS. 131 



tcrs also observed instances of botli mar<^inal and free central 

 placentation. Lastl}', St.-Hilaire foinid toward the southern 

 extreme of the ranfjc of Goniphia oletvforniis two forms which 

 he did not at first doubt were distinct species, but he subse- 

 quently saw them g-rowinp^ on the same bush ; and he then 

 adds, " A'oihl done dans uu memo individu des lof^es et un 

 style qui sc rattachent tantOt il un axe verticale et tantot ;l un 

 gynobase." 



In the case of these plants, will it be said that they have 

 been detected in the act of progTessin<T toward a hijjher state 

 of development ? On the contrary', I should infer, from such 

 characters varying;' so f^reatly, that tliey Avere of extremely 

 small importance to the plants themselves, of whatever impoi-- 

 tance they may be to us in our classifications. Although we 

 are quite ipiorant of the excitin<^ cause of each modification, 

 vet it st'cms probaljle from what we know of the relations of 

 varialjility to changed conditions, that under certain conditions 

 the one structure Avould have prevailed over the other, and 

 thus might have been rendered almost or quite constant. 

 l'>om th<? very fact of such diflerences being unimportant for 

 the welfare of the species, any slight dcAiations which did 

 occur Avould not be augmented or accumulated through natural 

 selection ; and they would be liable to obliteration through the 

 occasional intercrossing of distinct individuals. A structure 

 Avhich has hccn developed through long-continued selection, 

 when it ceases to be of service to the species, will generally 

 become variable, as we see with rudimentary organs ; for it 

 will no longer be regulated by this same power of selection ; 

 but on the other hand, when from the nature of the organism 

 and from a change in the conditions definite modifications have 

 been produced which are imimportant for the welfare of the 

 species, they may be, and apparently often have been, trans- 

 mitted in nearly the same state to numerous, otherwise modi- 

 fied descendants. Hair has been transmitted to almost all 

 mammals, feathers to all birds, and scales to all true reptiles. 

 A structure, whatever it may be, wiiich is common to many 

 alli(Ml forms, is ranked by us as of high systematic importance, 

 and consequently is often assimied by us in be of high vital 

 importance to tin* species. Thus, as I am inclined to believe, 

 morphological diilerenccs, which we consider as important — 

 such as the arrangement of the leaves, the divisions of the 

 ovarium, the position of the ovules, etc. — first appeared in 

 many cases as fluctuating variations, which sooner or later 



