COMPARATIVE ANATOMY AND MORPHOLOGY 353 



nature/' "hereditary propensity/' "latent characteristics; " in com- 

 parative anatomy such are "organs representing one another." 

 Like the phrase in physics, "horror of nature for a vacuum," they 

 correspond to nothing real. Many agree to this, but that does not 

 prevent us from continuing to bring them to the front as if they 

 contained a positive explanation. The progress of ideas lessens 

 their harmfulness, it does not destroy it. 



If, instead of proclaiming that two organs are homologues, we 

 should content ourselves with saying that they have the same embry- 

 onic rudiment, or similar connections, or a corresponding structure, 

 and that this authorizes us in a certain measure to think that they 

 come from the same rudiment in some ancestor more or less distant, 

 we should say only what we have the right to say, and what would 

 carry with it nothing difficult. It is not the same when we decree 

 a decisive epithet implying that there is something important and 

 fundamental in resemblances, while differences are accidental and 

 subordinate. 



There is, without our taking it into account, in this subordination 

 of certain characteristics to others, a remnant of the mystical con- 

 ception of the archetype. After having made the archetype object- 

 ive in the ancestral type, most of the time w r e lose sight of it, and we 

 give a fanciful reality to an entirely subjective type, a simple schem- 

 atization of abstract ideas. We create mental images of types of 

 organs, of types of structure indefinitely varied and divided up 

 according to the needs of the moment, and we lose sight entirely 

 of the idea of finding the realization of them in an ancestral form 

 previously existing. In each instance w T e are ready to answer that we 

 are taking the phylogenetic point of view, but most of the time it is 

 not so, and if it should be necessary to sustain that pretension with 

 good arguments, we should find none at all. 



This tendency to schematization is not wholly bad. It aids the 

 mind in grouping scattered facts in such a manner that one may 

 consider them as derived one from the other according to simple 

 rules. There is nothing inconvenient in conceiving of types of ani- 

 mals, types of organs, types of structure, as numerous, as varied, as 

 one wishes. But this is so only on condition of never forgetting that 

 they are creations of our minds, without any objectivity, destined 

 only to facilitate intellectual operations. The morphological type 

 must be considered only as an instrument of thought, and not as a 

 mystic entity, more or less hidden, which we may by observation and 

 study find again just as it is and not otherwise. We are at liberty to 

 construct it, the only condition being that it shall be advantageous 

 for study and that we shall never take it for anything else than it is. 



There must always be present in our minds the fact that an homo- 

 logy is never absolute, that organs represent one another in certain 



