Mutation Theory Criticised 



purple beech seems to be a mutation which has 

 originated at least three times over. 



Every one interested in biological theory 

 should read both Species and Varieties and Plant 

 Breeding by De Vries, works which are of 

 incalculable value to the horticulturist and agri- 

 culturist as well as to the biologist. 



While not wishing to detract in any way from 

 the truly splendid work done by De Vries, we 

 feel constrained to bring several charges against 

 him. 



Firstly, he suffers from the complaint that 

 seizes nine out of ten originators of new theories. 

 He pushes his theory to extreme lengths ; he 

 allows his imagination to run away with him. 

 We do not think that on the evidence available 

 he is justified in asserting that every species 

 passes through alternating periods of comparative 

 quiescence and periods in which it throws off, 

 as mutations, swarms of elementary species. He 

 is justified in asserting that discontinuous varia- 

 tion is by no means an uncommon phenomenon, 

 but further than this it does not seem safe to go 

 at present. 



Secondly, he ought to lay more stress on the 

 fact that Oenothera lamarckiana is a plant which 

 does not appear to be known in the wild state, 

 and that it is therefore possibly a hybrid plant, 

 and the so-called elementary species which it 

 gives off may be merely the varieties out of 



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