LAUGHTEK. 257 



kind ; if this be so, search to see if it be a mode 

 of expression direct, or by coincident development.* 



If my principles of expression and descriptions 

 of the modes of expression be somewhat true to 

 nature and practically useful, they will enable us 

 to analyze any good classical description of expres- 

 sion in man, if given in physical terms. Taking 

 any such description, we ought to be able to analyze 

 it, and replace, if necessary to our purposes, the 

 terms used by the author by our own terms, thus 

 giving his account in such terms as enable us to 

 submit the description to the test of direct obser- 

 vation. Such points in our author's description as 

 cannot be thus translated suggest that either our 

 principles are defective and incomplete, or that the 

 author's description is metaphysical or imperfect 

 from our point of view. 



If we take C. Darwin's f description of laughter, 

 we find it given in terms of nerve-muscular signs, 

 as are almost all his descriptions : 



" During laughter the mouth is open more or less 

 widely, with the corners drawn much backwards, 

 as well as a little upwards; and the upper lip is 

 somewhat raised. The drawing back of the corners 

 is best seen in moderate laughter, and especially in 

 a broad smile the latter epithet showing how the 

 mouth is widened. . . . Dr. Duchenne f repeatedly 

 insists that, under the emotion of joy, the mouth 

 is acted on exclusively by the great zygomatic 

 muscles, which serve to draw the corners backwards 



* See p. 273. f Expression of the Emotions,? p. 202. 



I " Mecanisme de la Physionomie Humaine," Album, Le'gendo vi. 



S 



