COMPARATIVE ANATOMY AND MORPHOLOGY 351 



Is not this subordination of propriety to substance an effect of 

 the influence which the materialistic conception of the universe 

 exercises upon our minds? Will our sons continue to think thus if 

 the energetic conception, quite as reasonable as the other, if not 

 more so, comes to outweigh it? And we ourselves, should we also 

 be on the affirmative side if we were the spiritual sons of other 

 natural philosophers, who had placed in the first rank in their con- 

 ceptions not organs, but functions, who had conceived of beings as 

 having to accomplish a series of physiological actions, the nature 

 of the organs by which they accomplish them being of subordinate 

 interest? 



Perhaps in that case we should be more struck by the fact that 

 the gill of the fish and the lung of the mammal both serve for respira- 

 tion than by the difference in their structure and in their material 

 origin. 



Is there not also more interest in seeing two organs, otherwise 

 very different both in structure and in phylogenetic origin, coming, 

 under the influence of the necessity to realize functions and by the 

 action of similar surrounding conditions, to have functional and 

 structural resemblances at times astonishing, than in establishing 

 the fact that two organs different in structure have a similar em- 

 bryonic or phylogenetic origin? 



Is the convergence of analogous organs less worthy of respect 

 than the homogeny of homologous organs? 



Here are a fish and an octopus. We admit, rightly, without doubt, 

 that they have not a common phyletic origin, or, at least, that their 

 community of origin, if it exists, dates from a stage when their 

 special organs were not differentiated. They both have an eye 

 which, in spite of certain differences, presents a conformity of struc- 

 ture really striking. In spite of their difference of origin and their 

 absence of relationships, the two protoplasms which constitute the 

 fertilized egg of the octopus and that of the fish both develop a spe- 

 cialized organ, an eye, which is remarkably similar in both. In the 

 two phyletic series of the octopus and the fish, under the influence of 

 a fundamental conformity of the substances constituting the organ- 

 ism and of a similar reaction to the analogous surrounding con- 

 ditions, there are formed these two eyes, which are almost identical, 

 although they are not related. 



Examples of this kind are numerous. Here is another quite as 

 striking. Many forms belonging to the groups of the mollusks, of 

 the ccelenterates and the worms have special organs of equilibra- 

 tion, statocysts, consisting of a heavy mass sustained by sensitive 

 hairs arising from the epithelial lining of a vesicle. The crustaceans 

 have on their antennules statocysts notably different in structure. 

 Only one, Mysis, has statocysts very similar to those of the mol- 



