Miscellaneous Papers. 261 



wave that swept over the world of thought following the publica- 

 tion of the "Origin of Species." 



Hugo De Vries says of the previous condition of the science of 

 origins (in speaking of Burbank's work) that, "Of great scientific 

 importance is the question whether repeated selections are suffi- 

 cient to bring about new forms, and, further, if by this means more 

 variations are produced. We have no facts to indicate this, but it 

 has great importance in the study of conditions. It is closely con- 

 nected with the question whether species slowly merge into one 

 another or whether they originate by mutations. In the former 

 case small deviations would increase in the course of generations, 

 and thus a long series of intermediate forms would connect man 

 and all other species. In the latter case of mutations a jump is 

 made without any intermediate stages." 



The doctrine of mutations is founded upon seven laws, which 

 De Vries thus states: "(1) New elementary species appear sud- 

 denly, without intermediate steps ; ( 2 ) they spring latterly from 

 the main stem, not affecting it; (3) they attain their full con- 

 stancy at once ; ( 4 ) some of the new strains are elementary species, 

 others are to be regarded as varieties ; ( 5 ) the same new species are 

 produced in a large number of individuals ; ( 6 ) mutations undergo 

 fluctuating variation, but the latter is not evolution ; and (7) muta- 

 tions take place in nearly all directions." 



Like Darwin, his great discovery was founded on experimenta- 

 tion, elaborate and long continued, and he worked upon well-known 

 and familiar facts. Stock-breeders and horticulturists have long 

 employed the method of making permanent the sudden changes 

 that produce variations, but no one before ever attempted to formu- 

 late the facts of mutation into a law and to conduct investigations 

 upon such a basis. 



Prof. Chas. A. White thus well summarizes the subject in 

 Science: "Species originate from other species through the or- 

 dinary function of reproduction, but they each originate suddenly 

 and completely by one mutative act, and not by the slow accumula- 

 tive variations of individuals. The beginning of the mutative 

 process which is due to some unknown natural determinative cause, 

 some molecular change in the germ-cell of the fertilized ovum, 

 whereby the new individual acquires changed structural characters. 

 The new species thus produced by mutation is in immediate pos- 

 session of clearly distinguishing and hereditarily transmissible 

 characters, and it has no more tendency to hybridize with any other 

 member of the mother species than have other species. Strains 



