Section IV., 1884. [ 161 ] Trans. Roy. Soc. Canada. 



Vlir. — On Mimetism in Inorganic Nature. 

 By E. J. Ch-apman, Ph. D., LL.D. 



(Read May 23, 1884.) 



The use of the term " Mimetism " in connection with inorganic bodies, may appear, at 

 first thong-ht, unwarranted ; but, iintil Mimetism is absolutely proved to arise from the 

 action of innate, as distinguished from external, forces, the extension of the term in its 

 present sense is not, I ho^ie to show, altogether without justification. In its conventional 

 acceptation the term is, of course, applied to the supposed results of a natiiral imitative 

 process by which certain animals — especially insects — inhabiting more or less restricted 

 geographical areas, have come to resemble either certain other animals of the district, or 

 certain vegetable forms, such as leaves, twigs, and the like, — the assumed function of this 

 mimetic principle being mainly the preservation of the individual from the attacks of its 

 enemies. 



Various opinions have been advanced in explanation of this peculiarity. It has been 

 regarded as the direct result of a protecting Providence, — the imitated form being thus 

 considered, not a superinduced condition, but an original, created condition. It has been 

 regarded, on the other hand, as simply the result of natural selection, originating in a very 

 slight and accidental approach towards the imitated type or object, this becoming more 

 and more developed and intensified in successive generations, until the imitation finally 

 becomes complete or reaches its extreme limit. 



Neither explanation is free from difiiculties, but the object of the present note is not 

 to discuss these, but simply to suggest a third view, namely, that this so-called mime- 

 tism may be neither original nor selective, in a Darwinian sense, but simply the result of 

 a kind of localism (to coin a word), — associated forms by some occult law becoming 

 impressed with mutual resemblances. Some principle of this kind does certainly prevail 

 to some extent in organic nature ; and the effect of this localism is curiously seen also in 

 certain associated minerals, in minerals which under normal conditions, or when occurring 

 apart, have scarcely two characters in common. A mimetism of this latter kind cannot 

 obviously be either providential or selective. Greneral resemblances among minerals (as 

 the resemblance of some varieties of apatite to beryl, of dark varieties of zinc blende to 

 ferruginous garnets, etc.,) have, of course, been long recognized and referred to ; but I am 

 referring, here, not to general resemblances, but to what may be called " special resemblances 

 under local conditions," and under these conditions only. I am not aware that this kind of 

 mineral mimetism has hitherto been pointed out. Although vaguely impressed by it for 

 some years, it first forced itself prominently on my attention during an examination of 

 some of the phosphate deposits of this immediate neighbourhood, that is, in the town- 

 ships of Templeton, Buckingham, etc., on the Quebec side of the Ottawa River. The 



Sec. IV., 1884. 21. 



