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. Unfortunately 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 Generationis' (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 noticeable 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 observations, 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 Collegium Medico-chirurgicum in Berlin, but was twice passed over in the appointment to professorships in that institution. He received an appointment 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 Pflanzenmetamorphose,' Berlin, 1867.
