38 ON GOETHE'S SCIENTIFIC RESEARCHES. 



grasped in his doctrine of the metamorphosis of plants, 

 the development, namely, of apparently very dissimilar 

 forms from parts originally alike. The posterior seg- 

 ments retain their original simple form ; those of the 

 breast-plate are drawn closely together, and develop feet 

 and wings ; while those of the head develop jaws and 

 feelers ; so that in the perfect insect, the original seg~ 

 \ ments are recognised only in the posterior part of the 

 body. In the vertebrata, again, a repetition of similar 

 parts is suggested by the vertebral column, but has ceased 

 to be observable in the external form. A fortunate glance 

 at a broken sheep's skull, which Groethe found by acci- 

 dent on the sand of the Li do at Venice, suggested to him 

 that the skull itself consisted of a series of very much 

 altered vertebrae. At first sight, no two things can be 

 more unlike than the broad uniform cranial cavity of the 

 mammalia, inclosed by smooth plates, and the narrow 

 cylindrical tube of the spinal marrow, composed of short, 

 massy, jagged bones. It was a bright idea to detect the 

 transformation in the skull of a mammal ; the similarity 

 is more striking in the amphibia and fishes. It should 

 be added that Groethe left this idea unpublished for a 

 long time, apparently because he was not quite sure how 

 it would be received. Meantime, in 1806, the same idea 

 occurred to Oken, who introduced it to the scientific 

 world, and afterwards disputed with Groethe the priority 

 of discovery. In fact, Groethe had waited till 1817, when 

 the opinion had begun to find adherents, and then de- 

 clared that he had had it in his mind for thirty years. 

 Up to the present day, the number and composition of 

 the vertebrae of the skull are a subject of controversy, 

 but the principle has maintained its ground. 



Groethe's views, however, on the existence of a common 

 type in the animal kingdom do not seem to have exercised 

 any direct influence on the progress of science. The 



