Origin of Wild Species 597 



pendently at least thrice, at dilt'erent periods 

 and in distant localities. 



From all these statements and a good many 

 others which can be found in horticultural and 

 botanical literature, it may be inferred that 

 mutations are not so very rare in nature as is 

 often supposed. Moreover we may conclude 

 that it is a general rule that they are neither 

 preceded nor accompanied by intermediate 

 steps, and that they are ordinarily constant 

 from seed from the first. 



Why then are they not met with more often? 

 In my opinion it is the struggle for life which is 

 the cause of this apparent rarity ; which is noth- 

 ing else than the premature death of all the in- 

 dividuals that so vary from the common type of 

 their species as to be incapable of development 

 under prevailing circumstances. It is obvious- 

 ly without consequence whether these deviations 

 are of a fluctuating or of a mutating nature. 

 Hence we may conclude that useless mutations 

 will soon die out and will disappear without 

 leaving any progeny. Even if they are pro- 

 duced again and again by the same strain, but 

 under the same unfavorable conditions, there 

 will be no appreciable result. 



Thousands of mutations may perhaps take 

 place yearly among the plants of our immediate 

 vicinity without any chance of being discovered. 



