XV THE RELATION OF FACTS TO THEORIES 321 



to such authoritative criticism ; and the fact that 

 those here submitted have not stood the ordeal 

 furnishes a strong presumption that a large number 

 of the cases contained in the literature of the subject 

 are likewise valueless. The term mimicry is applied 

 indiscriminately to all cases of colour resemblance ; 

 many of these can certainly not be so explained, 

 therefore we are justified in saying that at the 

 present time the explanation of the facts of colour 

 resemblance implicit in the use of the term " mimi- 

 cry" is insufficient, or to use Mr. Sedgwick's term, 

 inadequate. Mr. Sedgwick's observations in regard 

 to the cell -theory seem indeed eminently appli- 

 cable throughout to the theory of mimicry. " A 

 theory to be of any value must explain the 

 whole body of facts with which it deals. If it 

 falls short of this, it must be held to be in- 

 sufficient or inadequate ; and when, at the saitie 

 time, it is so masterful as to compel men to look at 

 nature through its eyes, and to twist stubborn and 

 unconformable facts into accord with its dogmas, 

 then it becomes an instrument of mischief, and 

 deserves condemnation, if only of the mild kind 

 implied by the term inadequate'' ("Remarks on 

 the Cell Theory,'' Compte Rendu, 3 me, Cong. Zool. 

 Leyde, 1896, p. 121). 



2. Protective Resemblance. — Although mimicry is 

 commonly said to be merely a special case of pro- 

 tective colour resemblance, it is in some respects 

 more difficult to understand than the latter, and it 

 is not perhaps necessary to suppose that the two 

 stand or fall together. It is, of course, to be clearly 

 understood that the existence of resemblances between 



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