NATURAL SELECTION, ETC. Ill 



quite compatible, by the other incompatible, with com- 

 munity of origin. But who can tell us what amount 

 of difference is compatible with community of origin f 

 This is the very question at issue, and one to be settled 

 by observation alone. Who would have thought that 

 the peach and the nectarine came from one stock? 

 But, this being proved, is it now very improbable that 

 both were derived from the almond, or from some 

 common ainygdaline progenitor? Who would have 

 thought that the cabbage, cauliflower, broccoli, kale, 

 and kohlrabi, are derivatives of one species, and rape 

 or colza, turnip, and probably ruta-baga, of another 

 species ? And who that is convinced of this can long 

 undoubtingly hold the original distinctness of turnips 

 from cabbages as an article of faith? On scientific 

 grounds may not a primordial cabbage or rape be as- 

 sumed as the ancestor of all the cabbage races, on much 

 the same ground that we assume a common ancestry 

 for the diversified human races ? If all our breeds of 

 cattle came from one stock, why not this stock from 

 the auroch, which has had all the time between the 

 diluvial and the historic periods in which to set off a 

 variation perhaps no greater than the difference be- 

 tween some sorts of domestic cattle ? 



That considerable differences are often discernible 

 between tertiary individuals and their supposed de- 

 scendants of the present day affords no argument 

 against Darwin's theory, as has been rashly thought, 

 but is decidedly in its favor. If the identification 

 were so perfect that no more differences were ob- 

 Bervable between the tertiary and the recent shells 

 than between various individuals of either, then Dar- 



