Vegetable Morphology. 45 



sterile. As Prof. Vines says, "The view that the 

 foliage-leaf is the primitive leaf-member, and that the 

 floral leaves are its derivatives, is based upon the fact 

 that, as a rule, the vegetative precede the reproductive 

 organs in ontogenesis. The opposite view, that the 

 most highly specialized floral leaf, the sporophyll, is 

 primitive, is based upon the fact that, phylogenetically, 

 the reproductive precede the vegetative leaves." 



It is refreshing, as Sachs says, to pass from the 

 period of the " Naturphilosophie" to " a chapter in mor- 

 phology where there is less dogmatism and 



i r 1 roundations 



less poetry, but a firmer basis of observation of exact 

 and induction". The increasing perfection Mor Phoio gy . 

 of the microscope, the formulation of the cell-theory in 

 1838-39, the beginning of embryological inquiries of a 

 more penetrating sort than hitherto, the emergence of 

 a palaeontological study of plants, the glimmering light 

 of more concrete evolutionary ideas (Alex. Braun, Un- 

 ger, Nageli), and perhaps some healthful influence from 

 the sister science of zoology, combined to strengthen 

 a new movement, about 1840, in the history of the 

 morphology of plants. Reacting from the vagaries of 

 the speculative school, botanists began to take their 

 science more seriously, and the key-note is struck in 

 the title of Schleiden's text-book (1842-43), Die Botanik 

 als inductive Wissenschaft. 



Matthias Jacob Schleiden (1804-1881), Schwann's 

 colleague in Jena and one of the founders of the cell- 

 theory, did much anatomical and embryological work, 

 but his chief historical importance is probably expressed 

 in his text-book, with the suggestive title already cited, 

 which came as a tonic to his times. "The difference", 

 Sachs says, "between this and all previous text-books 

 is the difference between day and night." Schleiden 

 was a combative critic, whose own work gave solidity 

 to his polemic, and who certainly did much to re-assert 

 the dignity of botany as an inductive science. 



Another leading spirit in the new movement was 

 Carl von Nageli. He did much to clear up the pheno- 

 mena of cell-formation, and may almost be said to have 

 introduced the "apical cell" to botanists; he laboured 



