394 



NINETEENTH CENTURY. 



PT. III. 



mense difference between them, as Lamarck had been with 

 the Hkeness of the lower animals. Cuvier thought that each 

 animal was at first created separately, and all its parts were 

 arranged expressly to meet its wants. He looked upon the 

 creation of each kind of animal as the making of a machine, 

 where we put a wheel here and a valve there expressly to 

 make it do the work required. 



Geoffroy St.-Hilaire, on the contrary, insisted that we 

 never find any part of an animal which we can say was made 

 expressly for it. Whenever we examine it closely enough 

 we find it is exactly the same as exists in other beings, only 

 its growth is altered so as to make it useful to that particular 

 animal. The pouch of the Kangaroo, he said, is only a fold 

 of the skin which is looser than in other animals ; the trunk 

 of the elephant is a nose which has become extremely long ; 

 the hand of a man, the leg of a horse, and the wing of a 

 bat, are the same organ and have the same bones, although 

 they serve such different purposes. * Nature,' he said, * has 

 formed all living beings on one plan, essentially the same in 

 principle, but varied in a thousand ways in all the minor 

 parts ; all the differences are only a complication and 

 modification of the same organs.' 



This similarity of structure, or homology as it is called, 

 which runs through all animals, was thus first clearly stated 

 by St.-Hilaire, and it has now been most carefully worked 

 out and confirmed by our living anatomists. Yet Cuvier op- 

 posed it to the last, for his mind was full, as we shall see 

 presently, of another idea which is equally true ; namely, how 

 perfectly each part of an animal is made to fit all the other 

 parts of his body ; and it seemed to him impossible that this 

 could be, unless each part was created expressly for the work 

 it had to do. 



