Miscellaneous Papers. 159^ 



ditions could be made permanent. The general acceptance and the 

 revolutionary effect of the idea of the origin of species by muta- 

 tions has been marvelous, and second only to the revolutionary 

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

 tion of the "Origin of Species." 



He 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 selec- 

 tions are sufficient 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 connected 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 suddenly, without intermediate 

 steps ; (2) they spring latterly from the main stem, not affecting it ; (3) 

 they attain their full constancy 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 

 Sciefice: 



"Species originate from other species through the ordinary function of 

 reproduction, but they each originate suddenly and completely by one muta- 

 tive act, and not by the slow accumulative 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 fertil- 

 ized ovum, whereby the new individual acquires changed structural charac- 

 ters. The new species thus produced by mutation is in immediate posses- 

 sion of clearly distinguishing and hereditary transmissible characters, and 

 it has no more tendency to hybridize with any other member of the mother 

 species than have other species. Strains thus produced are called elemen- 

 tary species, and differ distinctly but not widely from the mother species." 



