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THE AMERICAN NATURALIST Vol. XLID 



neetion the following passage in which he prepares the 

 ground for a belief in the possibility of similar abrupt and 

 wide variations under natural conditions. He remarks : 



Domesticated animals and plants can hardly have been exposed to 

 greater changes in their conditions of life than have many natural 

 species during the incessant geological, geographical, and climatal 

 changes to which the world has been subject; but domesticated pro- 

 he certainly did not choose with prophetic instinct those species which 

 would vary most, we may infer that all natural species, if exposed to 

 analogous conditions, would, on an average, vary to the same degree. 20 



But now let us take a specific example of spontaneous 

 variability which deeply impressed Mr. Darwin. It is 

 a case which was brought to his attention in 1860 by Pro- 

 fessor W. H. Harvey concerning Begonia frigid a, as to 

 which Mr. Darwin says : 



This plant properly produces male and female flowers on the same 

 fascicle; and in the female flowers the perianth is superior; but a 

 plant at Kew produced, besides the ordinary flowers, others which gradu- 



the perianth was inferior. To show the importance of this modification 

 under a classificatory point of view, I may quote what Professor Harvey 



This was written in the first edition of "Animals and 

 Plants under Domestication" (1868) and was allowed 

 to stand in the second and last edition ( 1S7:>). In both 



entirely different part of the work, that ''the wonderfully 

 anomalous flowers of Begonia frigida, formerly de- 

 scribed, though they appear fit for fructification, are 



