42 ON GOETHE'S SCIENTIFIC RESEARCHES. 



dry form.' And so, or nearly so, the problem stands to this 

 day. The difference may be brought out still more clearly if we 

 consider how physiology, which investigates the relations of vital 

 processes as cause and effect, would have to treat this idea of a 

 common type of animal structure. The science might ask, Is 

 it, on the one hand, a correct view, that during the geological 

 periods that have passed over the earth, one species has been 

 developed from another, so that, for example, the breast-fin of 

 the fish has gradually changed into an arm or a wing ? Or 

 again, shall we say that the different species of animals were 

 created equally perfect that the points of resemblance between 

 them are to be ascribed to the fact that in all vertebrate animals 

 the first steps in development from the egg can only be effected 

 by Nature in one .way, almost identical in all cases, and that 

 the later analogies of structure are determined by these features, 

 common to all embryos ? Probably the majority of observers 

 incline to the latter view, 1 for the agreement between the 

 embryos of different vertebrate animals, in the earlier stages, is 

 very striking. Thus even young mammals have occasionally 

 rudimentary gills on the side of the neck, like fishes. It seems, 

 in fact, that what are in the mature animals corresponding parts 

 originate in the same way during the process of development, so 

 that scientific men have lately begun to make use of embryology 

 as a sort of check on the theoretical views of comparative ana- 

 tomy. It is evident that by the application of the physiological 

 views just suggested, the idea of a common type would acquire 

 definiteness and meaning as a distinct scientific conception. 

 Goethe did much : he saw by a happy intuition that there was a 

 law, and he followed up the indications of it with great shrewdness. 

 But what law it was he did not see ; nor did he even try to 

 find it out. That was not in his line. Moreover, even in the 

 present condition of science, a definite view on the question is 

 impossible ; the very form in which it should be proposed is 

 scarcely yet settled. And therefore we readily admit that in this 

 department Goethe did all that was possible at the time when he 

 lived. I said just now that he treated nature like a work of 

 1 This was written before the appearance of Darwin's Oriyin of Species. 



