44 The Science of Life. 



say a stamen is a contracted petal as we may say of the 

 petal that it is an expanded stamen; or that a sepal is 

 a contracted foliage-leaf, as that a foliage-leaf is an 

 expanded sepal." 



The immediate successors of Goethe (for he had more 

 influence than Wolff) were too much dominated by the 

 Subse uent m d and method of the " Naturphilosophie" 

 Develop- to effect much progress. There was a ple- 

 thora of speculation which often lost all touch 

 with reality, speculation as to "polarities" and "re- 

 juvenescence", as to "the wave-pulse of metamorpho- 

 sis" and "the spiral tendency of growth", and a host 

 of similar verbalisms. As Prof. Vines says, the period 

 "was fruitful in little else than wild theorizing", but it 

 ' * fortunately culminated in a reaction to investigation 

 and induction. On a sudden, as it were, a band of men 

 arose, of brilliant ability and indefatigable industry, 

 whose great achievements have revolutionized not only 

 the department of morphology, but the other branches 

 of botany as well; I need only mention the names of 

 Schleiden, Von Mohl, Nageli, Hofmeister, Robt. Brown, 

 Irmisch, Hanstein, Alex. Braun." From these, through 

 De Bary and Sachs, we pass naturally to Goebel and 

 Bower, and other active morphologists of to-day. 



In modern times the morphological equivalence of 

 appendicular organs has been confirmed in three ways : 

 (a) by careful observation of actual cases of transfor- 

 mation, e.g. of bud-scales; (b) by the microscopic inves- 

 tigation of apparently homologous parts; and (c) by 

 more precise embryological evidence. There is no doubt 

 that one kind of appendicular organ may be metamor- 

 phosed into another, or more generally, "that there is a 

 genetic relation between the forms of the same mem- 

 ber". 



The direction in which the evolution has taken place 

 whether from foliage-leaf to reproductive-leaf or vice 

 versd remains the subject of discussion. Goebel, for 

 instance, strongly maintains the older view that the 

 spore -bearing leaf (sporophyll) is a metamorphosed 

 foliage-leaf, while Bower maintains that the foliage-leaf 

 is a metamorphosed sporophyll, which has become 



