The Evolution of Organisms 157 



De Vries' Evening Primroses Let us recall, for a 

 moment, the case of the Evening Primrose (Oeno- 

 thera lamarckiana), which Professor Hugo De 

 Vries found as an escape in a potato-field at Hil- 

 versum in Holland. Its chief interest was its 

 changefulness; it was, so to speak, frolicking in its 

 freedom; it was in a variable mood. Almost all its 

 organs were varying as if swayed by a restless 

 tide of life. It showed minute fluctuations from 

 generation to generation; it showed extraordinary 

 freaks such as fasciation and pitcher-forming; it 

 showed hesitancy as to how long it meant to live, 

 for while the majority were biennial, many were 

 annual, and a few were triennial; best of all, it 

 showed what could hardly be otherwise described 

 than as new species in the making. From this 

 stock, De Vries obtained in a short time half a 

 dozen or more distinct varieties or elementary 

 species, breeding true generation after genera- 

 tion. In short, he was fortunate enough to have 

 found a plant in process of rapid evolution. It is 

 rash to generalize as yet, but other cases of muta- 

 tion are now being studied, and it may be that in 

 many instances "new varieties are produced from 

 existing forms by sudden leaps." If there are 

 many such cases, the aspect of the evolution 

 theory will have to be changed; we shall attach 

 less importance to the accumulation of minute 

 fluctuations, and we shall not have to lay such 



