VARIATION AND MUTATION 



161 



and that these may be to a degree persistent in heredity. Of 

 such nature was the Ancon sheep, the Mauchamp sheep, the 

 iceberg blackberry, and numerous other races or forms known in 

 the domestication of animals, or the cultivation of plants. The 

 generally normal structure of such individuals distinguishes 



FIG. 100. A branch of the green Georgine, in which the inflorescence leaves and some 

 of one branch (the right-hand one) are green like the rest of the plant, while the 

 other varieties are red and in normal condition. (After de Vries.) 



them from monstrosities, which are usually freaks of develop- 

 ment rather than of heredity. 



The name " saltation, ;; or in recent years "mutation/ 7 has 

 been applied to extreme fluctuation, the immediate cause of 

 which is unknown. The experiments of de Vries on the salta- 

 tions of the descendants of the evening primrose (called (Eno- 

 thera lamarckiana) have drawn general attention again to the 

 possibility that saltation has had a large part in the process of 



1 The word mutation was first used not for saltations but for the slow 

 fluctuation in successive geological periods. 



