EXPRESSION OF EMOTIONS. 189 



ductions, together with the causes and laws of 

 variation, inheritance, and the intercrossing of plants, 

 are the sole subjects which I have been able to write 

 about in full, so as to use all the materials which I 

 have collected." 



" The Expression of the Emotions," at first in- 

 tended as a chapter of the "Descent," was begun, 

 only two days after the proofs of the latter had 

 been corrected, on January 15th, 1871. The book 

 was published in the autumn of the following year ; 

 the edition consisted of 7,000 copies, and 2,000 were 

 printed at the end of the year ; and this, we are told, 

 was a mistake, as it prevented the appearance of 

 a second edition, with notes and corrections, during 

 the author's lifetime. Darwin had begun to take 

 notes on this subject when his first child was born, 

 December 27th, 1839, for he tells us that, even then, 

 he felt convinced " that the most complex and fine 

 shades of expression must all have had a gradual 

 and natural origin." (" Autobiography.") 



In this work Darwin argues with great wealth of 

 illustration and the record of numberless interesting 

 observations, that the movements of expression are to 

 be explained by three principles. The first of these is 

 that movements made in gratifying some desire 

 become by repetition so habitual that the slightest 

 feeling of desire leads to their performance, however 

 useless they may then be. The second principle is 

 that of antithesis " the habit of voluntarily perform- 

 ing opposite movements under opposite impulses." 



