Vegetable Morphology. 43 



story of his "painful surprise" when Schiller said, 

 "This is not an observation, it is an idea", is interest- 

 ing- to the student of scientific method, the obvious fact 

 being that Goethe reached his conclusion deductively, 

 for his mind was full of the evolution idea, and that he 

 tried to verify it inductively a thoroughly sound pro- 

 cedure. 



Goethe's theory of the morphological equivalence oi 

 appendicular organs was developed in his famous essay 

 Versuch die Metamorphose der Pflanzen zu erkldren, pub- 

 lished in 1790. " In this brilliant essay", Prof. Geddes 

 says, "the doctrine of the fundamental unity of floral 

 and foliar organs is clearly enunciated, and supported by 

 arguments from anatomy, development, and teratology. 

 All the organs of a plant are thus modifications of one 

 fundamental organ the leaf, and all plants are in like 

 manner to be viewed as modifications of a common 

 type the Urpflanze." 



Prof. Vines points out that Goethe's evidence, if 

 strictly considered, was by no means conclusive. He 

 rested his case chiefly on the occurrence of transitional 

 forms which connect different kinds of leaf-organs, and 

 on monstrosities, such as stamens which become petals. 

 But it is possible to find forms at least superficially tran- 

 sitional between leaf and shoot; and to argue from 

 monstrosities is always precarious. The theory lacked, 

 what Wolff had begun to supply, the " embryological 

 criterion of homology". Moreover, as Goethe himself 

 felt keenly, the theory remained vague and unsatisfac- 

 tory in regard to what it was that had been the subject 

 of all the supposed metamorphosis. "What he sought", 

 Prof. Vines says, "was the morphological concept of 

 the leaf; and the reason why he failed to form it was 

 that the morphological botany of his time was too 

 superficial and too physiological to admit of such con- 

 ception." And as the observed facts of transitions and 

 abnormal changes pointed to both ascending and 

 descending metamorphosis, Goethe was puzzled, as 

 many of us are still, as to the direction of the supposed 

 evolution. Is it from vegetative leaf to floral leaf, or 

 vice versa? "For", as Goethe said, "we can as well 



