CHAPTER V 



ETIENNE (.'.EUFFKOY SAIKT-IJILAIKli 



K. GEOI-TKOY made an experiment, unsuccessful but 

 instructive. He tried to found a science of pure morphology ; 

 he failed : his failure showed, once and for all, that a pure 

 morphology of organic forms is impracticable. 



Already, in 1/96, in one of his earliest memoirs, 1 

 Geoffroy was guided by the idea that Nature has formed 

 all living things upon one plan. Organs which seem 

 anomalous are merely modifications of the normal ; the trunk 

 of an elephant is formed by the excessively prolonged 

 nostrils, the horn of a rhinoceros is simply a mass of 

 adhering hairs. In general, however varied their form, all 

 organs are simply variations of a common scheme ; Nature 

 employs no new organs. Organs which are rudimentary, 

 such as the clavicles in the ostrich and the nictitating 

 membrane in man, bear witness to the unity of plan. In 

 this Geoffroy goes no further than his predecessors. They 

 too had recognised homologies of organs ; they too had 

 interpreted rudimentary organs as vestiges of an original 

 plan. 



In a series of papers published in 1807, Geoffroy took 

 a further step, and sought to establish homologies which 

 were not obvious homologiVs, too, not so much of organs as 

 of parts. 



These memoirs (published in the .\>/n<i/cs du Slnscnin 

 <nfis/<>in- natnrcllc, vols. ix. and x., 1807) dealt with the 

 homology between the bones of the pectoral fin and girdle in 

 fish and the bones of the arm and shoulder-girdle in higher 



1 " Mcmoirc sur les rapports nature-Is dcs makis,' ; M>i<isin Encyclo- 

 vii. 



