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THE AMERICAN NATURALIST [Vol. XLII 



caped from some garden. Under cultivation he continued 

 to breed them, and produced others. But his plants were 

 all under abnormal environments. Dr. Lutz, whom we 

 all know, is doing some exceedingly interesting experi- 

 ments upon certain small flies, Drosophila ampelophila. 

 He has produced some remarkable sports or "muta- 

 tions, ' ' and the surprising thing is that he finds that such 

 sports breed true, that there is an apparent loss of fer- 

 tility between them and the normal forms. But I think 

 it is absolutely certain— and I speak as an entomologist 

 fairly familiar with flies— that it would be impossible to 

 produce species of his sports, even though they were bred 

 for a thousand years. As some of us know, polydactyl 

 cats are rather abundant in some parts of Connecticut, 

 breeding true— but who believes in a species of six-toed 

 cats? It is rather unfortunate that breeders confine their 

 attention almost exclusively to plastic forms, that is, to 

 geologically recent types. Let some one try experiments 

 with archaic forms and watch the results. 



Experimental breeding and ecology are the two fields 

 of biological research which promise most at present; 

 they will doubtless contribute not a little to our knowl- 

 edge of the methods of evolution, and correct not a few 

 errors in taxonomy ; but I say, with full deliberation, that 

 experimental breeding without a wide knowledge of tax- 

 onomy will lead to false conclusions and be comparatively 

 barren of results. The experimentalist, of all men, must 

 be well acquainted with varietal specific and generic 

 characters in the groups which he studies, or he will be 

 working blindly. And I am sorry also to say that some 

 of the severest criticisms of taxonomists and taxonomy 

 have come from some of these men. 



