LAXGUAGE. 103 



ventional signs as used by man is, that no line of strict 

 demarcation can be drawn between them and natural signs ; 

 the latter shade off into the former by gradations, which it 

 becomes impossible to detect over large numbers of individual 

 cases. With respect to tones, for example, it cannot be said, 

 in many instances, whether this and that modulation, which is 

 now recognized as expressive of a certain state of feeling, has 

 always been thus expressive, or has only become so by con- 

 ventional habit ; although, if we consider the different tones by 

 which different races of mankind express some of their similar 

 feelings, we may be sure that in these cases one or other of the 

 differences must be due to conventional habit — just as in the 

 converse cases, in which all mankind use the same tones to 

 express the same feelings, we may be sure that this mode 

 of expression is natural. And so with gestures. Many which 

 at first sight we should, judging from our own feelings alone, 

 suppose to be natural — such, for instance, as kissing — are 

 shown by observation of primitive races to be conventional ; 

 while others which we should probably regard as conventional 

 — such, for instance, as shrugging the shoulders — are shown 

 by the same means to be natural* 



But for our present purposes it is clearly a matter of no 

 consequence that we should be able to classify all signs as 

 natural or conventional. For it is certain that animals employ 

 both; and hence no distinction between the brute and the man 

 can be raised on the question of the kind of signs which they 

 severally employ as natural or conventional. This distinction, 

 therefore, may in future be disregarded, and natural and 

 conventional signs, if made intentionally as sig?is, I shall con- 

 sider as identical. For the sake of method, however, I shall 

 treat the sign-making faculty as exhibited by man in the 

 order of its probable evolution ; and this means that I shall 

 begin with the most natural, or least conventional, of the 

 systems. This is the language of tone and gesture. 



• For information on all these points, sec Darwin, Expression of the Emotions. 



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