LIFE OF DARWIN, 127 



devised appeal to nature ; observation over a wide field 

 as to the varied races of man still existing, utilising the 

 aid of travellers and residents in many lands ; observation 

 of domestic animals in familiar and in untried circum- 

 stances ; observation of infants, especially his own, from 

 a very early age ; observation of the insane, who are 

 liable to the strongest passions, and give them uncontrolled 

 vent. It was in 1867 that Darwin circulated his group 

 of questions designed to ascertain the mode of expressing 

 every emotion, and their physical concomitants in every 

 possible race. Sculpture, paintings, and engravings, 

 afforded little evidence, because beauty is their main 

 object, and " strongly contracted facial muscles destroy 

 beauty." Information was specially sought as to natives 

 who had had little communication with Europeans, and 

 in whom imitation might not have destroyed ancestral 

 and original expression. 



The result was to develop three principles which 

 appeared, in combination, to account for most of the 

 expressions and gestures involuntarily used by man and 

 animals. The first was that of serviceable associated 

 habits : certain complex actions being somehow service- 

 able in 'particular states of mind, to gratify and relieve 

 certain sensations, desires, &c., whenever the same state 

 of feeling is repeated, there is a tendency to the same 

 movements or actions, though they may not then be of 

 the least use. The second principle, that of antithesis, 

 is the converse of the last; when an opposite state of 

 mind is induced, there is an involuntary tendency to 

 directly opposite movements, though of no use. The 

 third principle, that of the direct action of the nervous 



