Chap. XIV. AND SUMMARY. 355 



guage used by the deaf and dumb. On the contrary, 

 every true or inherited movement of expression seems 

 to have had some natural and independent origin. But 

 when once acquired, such movements may be voluntarily 

 and consciously employed as a means of communication. 

 Even infants, if carefully attended to, find out at a very 

 early age that their screaming brings relief, and they 

 soon voluntarily practise it. We may frequently see a 

 person voluntarily raising his eyebrows to express sur- 

 prise, or smiling to express pretended satisfaction and 

 acquiescence. A man often wishes to make certain ges- 

 tures conspicuous or demonstrative, and will raise his 

 extended arms with widely opened fingers above his 

 head, to show astonishment, or lift his shoulders to his 

 ears, to show that he cannot or will not do something. 

 The tendency to such movements will be strengthened 

 or increased by their being thus voluntarily and repeat- 

 edly performed; and the effects may be inherited. 



It is perhaps worth consideration whether move- 

 ments at first used only by one or a few individuals to 

 express a certain state of mind may not sometimes have 

 spread to others, and ultimately have become universal, 

 through the power of conscious and unconscious imita- 

 tion. That there exists in man a strong tendency to 

 imitation, independently of the conscious will, is certain. 

 This is exhibited in the most extraordinary manner in 

 certain brain diseases, especially at the commencement 

 of inflammatory softening of the brain, and has been 

 called the " echo sign." Patients thus affected imitate, 

 without understanding, every absurd gesture which is 

 made, and every word which is uttered near them, even 

 in a foreign language. 1 In the case of animals, the jackal 



1 See the interesting facts given by Dr. Bateman on 

 4 Aphasia,' 1S70, p. 110. 



