250 Phytotoiny in the Eighteenth Century. [BOOKII. 



a solitary figure among his contemporaries, not only because 

 he was the first since Malpighi and Grew who devoted labour 

 and perseverance to the study of the anatomy of plants, but 

 still more because at a time, when the structure even of 

 matured vegetable organs was almost a forgotten subject, he 

 endeavoured to penetrate into the history of the development 

 of this structure and the formation of cellular tissue. Unfor- 

 tunately he was not directed to this by an exclusive interest 

 in phytotomy, but by a more general question which he 

 endeavoured to set at rest in this manner; he wished to refute 

 the prevailing theory of evolution by demonstrating the 

 development of the organs of plants, and to obtain an 

 inductive basis for his doctrine of epigenesis. Though he was 

 often diverted by these means from the pursuit of purely 

 phytotomic questions, yet his famous work, 'Theoria Genera- 

 tionis' (1759) is nevertheless important in the history of 

 phytotomy ; for though it was disregarded by botanists during 

 the succeeding forty years, or at any rate exercised no notice- 

 able influence, yet it was Wolff's doctrine of the formation of 

 cellular structure in plants which was in the main adopted 

 by Mirbel at the beginning of the present century, and the 

 opposition which it encountered contributed essentially to 

 the further advance of phytotomy. This late but lasting 

 influence of Caspar Friedrich Wolff's work was due not to 

 the actual correctness but to the thoughtfulness of his obser- 

 vations, and to the earnest desire which inspired them to 



Haller, the representative of the theory of evolution against which 

 this work was directed, replied to it in a kindly spirit and entered into 

 a correspondence with its youthful author. After lecturing on medicine in 

 Breslau, he was admitted to teach physiology and other subjects in the Col- 

 legium Medico-chhurgicum in Berlin, but was twice passed over in the 

 appointment to professorships in that institution. He received an appoint- 

 ment in the Academy of St. Petersburg from the Empress Catherine II in 

 1766, and died in that city in 1794. See Alf. Kirchhoff, ' Idee der Pflan- 

 zenmetamorphose,' Berlin, 1867. 



