342- THE HISTORY OF BIOLOGY 



similarities between bones of different vertebrates during the embryonic stage 

 that GeofFroy had established, maintaining that the method employed in 

 Geoffrey's investigations was by no means new, but originated in Aristotle, 

 and that Geoffroy's talk of a uniform plan for the structure of the entire 

 animal kingdom was mere empty words without any real meaning and with- 

 out any equivalent in nature. This reply greatly offended Geoffroy, where- 

 upon there started one of those long-drawn-out controversies so common 

 in scientific history, when two persons of utterly different temperament fall 

 foul of one another, and when the longer it lasts, the more unprofitable it 

 becomes. Strikingly enough, Geoffroy at once desisted from maintaining the 

 comparison between ink-fish and vertebrates; instead, he transferred the 

 whole discussion to the sphere of the vertebrates. Similarly, he replaced 

 the expression '' unite de plan," to which Cuvier had objected, by the phrase 

 " tbeorie des analogues," but at the same time emphatically declared that this 

 theory was entirely new; for while the old comparative anatomy concerned 

 itself merely with the form and function of an organ, the new theory took 

 for comparison all the parts of which an organ was composed. As an in- 

 stance of this he cited the hyoid bone in mammals, which he found to be 

 composed of different parts in different animals, and also the opercular bones 

 in fishes. Here Geoffroy was clearly referring to what we nowadays call 

 homology — the likeness that exists in the evolutional history of certain 

 organs, which warrants comparison in a manner different from what the 

 mere functions of these organs would justify. But unfortunately he was too 

 vague in his speculations to be able to give them plausible form; in the sub- 

 sequent discussions before the Academy, Cuvier pointed out a great number 

 of errors of detail even in Geoffroy's comparisons of the hyoid bones in the 

 vertebrates, not to mention his idea that this bone occurred in crayfish. Fur- 

 ther Geoffroy had a weakness for general philosophical speculation that must 

 have seemed utterly absurd to his sober-minded opponent. In the introduc- 

 tion to a book in which he collected his contributions to the discussion, 

 there occurs the following passage, which, like Schelling's, must be quoted 

 in the original: Pour cet ordre des considerations il n est plus d' animaux divers. 

 Un seul fait les domine, c est comme un seul etre qui apparait. 11 est, il reside 

 dans V Animalite; etre ahstrait, qui est tangible par nos sens sous des figures 

 diver ses." Such an expression of views was quite in Goethe's style — he, 

 too, as is well known, took part in the dispute as a warm supporter of 

 Geoffroy; he considered that the latter's cause was the cause of natural phi- 

 losophy itself, and in this he was certainly right. For if there existed in 

 Geoffroy's speculations advanced ideas of the greatest value even for modern 

 comparative anatomy, they were nevertheless an expression for that same 

 romantic natural philosophy, that same striving after an ideal unity in exist- 

 ence, which was then prevalent in Germany and which, in fact, GeofFroy 



