1871.] 185 [Wilder. 



Definition. The uiorphotropic relation between parts upon oppo- 

 site sides of structural planes. 



Example. See hypsetropy, meketropy and platetropy. 



No better evidence of the need for a uniform and simple terminology 

 of ideas could be asked, than is given by the above synonomy; but it 

 will be observed that the third and fourth terms mean something more 

 than the rest; it is difficult to say just what Oken meant by duplicity 

 and indeed many of the great physiophilosopher's expressions are be- 

 yond strict logical interpretation, although it is evident that he ine 

 wardly perceived much more than he was able to express in definite 

 terms; his Physiophilosophy was written in a kind of inspiration, 

 (as he admits in the preface to the English translation) , and inspira- 

 tion is only suggestive in science, never conclusive; his term polarity 

 too is used in many different senses, and Wyman has well said, 55, 

 257, that "it does not appear precisely what he meant by the word 

 ' pole.' " 



At any rate polarity (and perhaps duplicity) is the name for a 

 general law of organization which is analogous to the physical polar 

 force, Wyman, 55, 254; the result of its undisturbed action would be 

 an absolute symmetry; the one is a cause, the other the effect of its 

 action', and all the other terms given in our list are synonyms of 

 symmetry, and not of polarity ; I do not propose a name for the force 

 for it is not yet understood ; but I would urge that symmetry is in 

 eligible as a technical term on account of its common use in several 

 other senses; of all the other terms antitropy seems to express most 

 clearly the idea we wish to convey, a respective symmetry of struct- 

 ure and not necessarily of external form; for this latter is early 

 and most extensively modified by the telical antagonist of our hypo- 

 thetical "polar force," the so-called "vital force." See Wyman, 55, 

 258. 



But while antitropy seems best adapted for our purpose, it is not 

 quite clear that those who have already employed it have meant to 

 convey the precise idea which we have under consideration; I have 

 not been able to obtain the works of Schimper and Braun, but I judge 

 that they used antitropy to designate any antagonistic relation be- 

 tween parts of the plant embryo, and between opposite leaves upon 

 the stem, although T am not sure that they always included an idea of 

 real homology in this antagonism of position; Agassiz has used the 

 term antitropy to express the relation between spheromeres upon oppo- 

 site sides of a radiate, 200, 3, 260; and here, of course, the general 



