A Century of Science 15 



Linnaeus that believers in some sort of a develop- 

 ment theory, often fantastic enough, began to be 

 met with. The facts of morphology gave further 

 suggestions in the same direction. Such facts were 

 first generalized on a grand scale by Goethe in his 

 beautiful little essay on " The Metamorphoses of 

 Plants, "written in 1790, and his " Introduction to 

 Morphology," written in 1795, but not published 

 until 1807. In these profound treatises, which were 

 too far in advance of their age to exert much influ- 

 ence at first, Goethe laid the philosophic foundations 

 of comparative anatomy in both vegetal and animal 

 worlds. The conceptions of metamorphosis and of 

 homology, which were thus brought forward, tended 

 powerfully toward a recognition of the process of 

 evolution. It was shown that what under some 

 circumstances grows into a stem with a whorl of 

 leaves, under other circumstances grows into a 

 flower; it was shown that in the general scheme 

 of the vertebrate skeleton a pectoral fin, a fore leg, 

 and a wing occupy the same positions : thus was 

 strongly suggested the idea that what under some 

 circumstances developed into a fin might under 

 other circumstances develop into a leg or a wing. 

 The revelations of palaeontology, showing various 

 extinct adult forms, with corresponding organs 

 in various degrees of development, went far to 



