are quite artificial. It matters not, also, what we call 

 these finally not further resolvable forms. Therefore let 

 us accept De Vries' terminology and use the term elemen- 

 tary species ; the real point of the inquiry is how did these 

 forms arise. It is upon this that De Vries' work has 

 thrown a great light. He has shown that they may arise 

 suddenly and without previous preparation from pre- 

 existing forms, in which case the elementary species may 

 be termed mutants, and the theory which has to do with the 

 investigation of their origin the Mutation Theory. 



The next task then is to examine more closely the 

 methods which De Vries employed, the evidence which he 

 has to support his views, both as to the observations on 

 the origin of these mutants and their behavior after they 

 have come into being, and further, what success subsequent 

 investigators have had in supporting De Vries' evidence, 

 and how far they have extended his conclusions. In the 

 first place, it may be remarked that the conclusions as first 

 published in 1901 and 1902 were not the outcome of any 

 hasty experiments and ill digested data, but were the re- 

 sult of seventeen years of the most careful and painstak- 

 ing work, and a fine example of the best kind of quiet, 

 faithful research, removed from the rush of affairs and the 

 demand for immediate results, the final conclusion of 

 which fully warranted the time and labor expended. 



As is well known, Professor de Vries found in La- 

 marck's evening primrose Oenothera Lamarckiana 

 a plant most favorable for observation, though his conclu- 

 sions are not based on that form alone. The most care- 

 fully guarded pedigree cultures were made from the true 

 Lamarckiana type, and the astonishing result developed 

 that among the offspring of these certain forms, to the 

 number of about four per cent, showed new and striking 

 differences. In all, more than a dozen new forms were ob- 

 tained which, if they could be bred at all, bred true to their 



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