IN MEMORIAM: CHARLES DARWIN 



descended from one and the same ancestral form. 

 The differences extend throughout the whole 

 bony framework as well as throughout the mus- 

 cular and nervous systems, and exceed in amount 

 the differences by which naturalists often adjudge 

 species to be distinct. Through what agency 

 has man produced such results as these ? He 

 has produced them simply by taking advantage 

 of a slight tendency to variation which exists 

 perpetually in all plants and animals, and which 

 exhibits itself in the simple fact that nowhere do 

 we ever find any two individuals exactly alike. 

 Taking advantage of these individual variations, 

 the breeder simply selects the individuals which 

 best suit his purpose, and breeds them apart by 

 themselves. The qualities for which they are se- 

 lected are propagated and enhanced through in- 

 heritance and renewed selection in each succeed- 

 ing generation, until by the slow accumulation 

 of small differences a new race is formed. And 

 thus we have peaches and almonds from a com- 

 mon source, grapes to eat and grapes to make 

 wine of, pointer-dogs and mastiffs, and so on 

 throughout the list of cultivated plants and do- 

 mesticated animals. 



These facts about variation under domestica- 

 tion are for the most part well known, and the 

 alleged cause of variation, in selection by man, 

 is not an occult cause, but is a phenomenon per- 

 fectly familiar to every one. Starting from this 

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