METAMORPHOSIS IN PLANTS. 83 



should have failed to come to a full apprehension of the 

 truth ; but his failure may be easily accounted for. In the 

 first place he was hampered by the prevalent fantastic 

 theory of evolutionary development which had originated 

 with Csesalpini : l and in the second place his mind was 

 doubtless so preoccupied with what has turned out to be the 

 altogether unimportant theory of Prolepsis, that he was un- 

 able to perceive the great fundamental principle which lay 

 exposed before him. 



We pass now to Wolff. Though an animal physiologist 

 and anatomist, Wolff turned his attention to plants, and 

 with remarkable results, in the course of his investigations 

 in support of his theory of Epigenesis by which he contro- 

 verted the prevalent theory of evolutionary development. 

 For the first time since Malpighi, 2 the minute structure and 

 more especially the development of the organs of plants 

 were carefully studied. As the chief result of his investiga- 

 tions, Wolff 3 made the important discovery that the " appen- 

 dicular organs," as he termed the leaves, are developed at the 

 growing-point, punctum vegetationis he called it, of the 

 stem ; and that this is true whether they be ordinary leaves, 

 as he observed in the common Cabbage, or whether they be 

 parts of the flower, as he observed in the Bean ( Vicia Faba). 

 Seeing, then, that all these appendicular organs have the same 

 mode of orioin, he concludes as follows: 4 "In the entire 

 plant, whose parts we wonder at as being, at the first glance, 

 so extraordinarily diverse, I finally perceive, after mature 

 consideration, and recognise nothing beyond leaves and stem 

 (for the root may be regarded as a stem). Consequently 

 all parts of the plant, except the stem, are modified leaves." 



With this quotation before us, no other conclusion can 

 be drawn than that Wolff had anticipated Goethe's dis- 

 covery in all essential points, though his exposition of it is 



1 De Plantis, 1583. 



- Malpighi, Anatomes Plantarum Idea, 1675; as also other works in 

 his Opera omnia, Lond. 1686; Lugd. Batav., 1687. 



3 Theoria Generations, 1759; Theorie von der Generation, 1764. 



4 " De Formatione Intestinorum," Nov. Comment. Acad. Petrop., xii., 

 1767. 



