422 ANNUAL EEP'OET SMITHSONIAN INSTITUTION, 1918,, 



ago. 1 Prof. Ed. Bordage, who has published lately a special study 

 of the whole question of mutations, also came to a similar con- 

 clusion. 2 



To begin with, Bordage points out that the Oenothera lamarckiana 

 is, according to different botanical authorities, a hybrid, either be- 

 tween Oe. grandifora and Oe. biennis, both imported to Europe 

 in the eighteenth century (the former was known at Harlem since 

 1756), or between different varieties of Oe. biennis, which is a very 

 variable species. 3 But even if it was not a hybrid, the evening 

 primrose has undergone so many changes in the conditions of its 

 culture during the last 150 years that its present considerable vari- 

 ability may be a consequence of these changes. 



All taken, Prof. Bordage comes to the opinion that a mutation 

 is not something substantially different from an ordinary variation. 

 It is only " a sudden external expression of internal processes, accom- 

 plished gradually and without interruption. * * * Between the 

 sudden and the slow variation there is no absolute difference. Both 

 can be considered as the effects of the same law, manifesting them- 

 selves more or less rapidly." 



VI. 



" Mutations," we have just seen, were described as " congenital vari- 

 ations." But every variation of form and structure, once it is in- 

 herited, implies a "congenital variation." Some change must have 

 taken place in the germ cells whatsoever the origin of the variation 

 or the position of the germ cells in the organism may be. We learn, 

 it is true, from the experiments of MacDougal and Tower that cer- 

 tain inheritable changes may be obtained by a direct action of ex- 

 ternal agencies (temperature and so on) upon the germ cells. Of 

 course, they may. But nobody has yet proved that changes produced 

 in the body cells can not affect the germ cells, while modern research 

 tends to prove quite the contrary. 



Consequently, we are not astonished to learn that de Vries, having 

 recognized in his last work, Gruppenweise Artbildung, that every 



1 Thus, fully recognizing that " de Vries has established in the domain of heredity a 

 mass of facts, the theoretical value of which still remains in some respects to be estab- 

 lished by further research," Prof. Plate, in analyzing the mutation theory in his monu- 

 mental critical work (Selektionsprinzip, pp. 384-435), wrote: "The mutation theory 

 obtained an apparent temporary success because il introduced new words for well-known 

 facts and conceptions, and thus awakened the idea that a new knowledge had been won. 

 It is evident that for the theory of descent no real progress in advance of Darwin had 

 been won in that direction." In another very elaborate work, Vererbungslehre (vol. ii, of 

 his Handbiicher der Abstammungslehre, Leipzig, 1913, pp. 430-475), Plate returned once 

 more to this subject, and after a careful examination of the whole question (including 

 Mendelism) he worded his final conclusion as follows : " Those thoughts in it [the 

 mutations theory] which are correct are not new, and its new components can not be 

 accepted " (p. 473). 



3 " Les nouveaux problems do l'heredite" : la theorie de la mutation," in Biologica, ii, 

 1912. 



3 The latter is the opinion of Mr. Boulenger, an authority on the subject; and the 

 former is the view taken by Davy and several other botanists. 



