xi] OF EVOLUTION 143 



the manner in which new sensations and passions were 

 exhibited by them. His dog and other annuals, for 

 whom he always showed the greatest fondness, were 

 closely watched with the object of noting correspond- 

 ences between their mental and moral processes and 

 their modes of exhibiting them and our own ; while 

 visits were made by him to the Zoological Gardens 

 with the same object. By reading and correspondence 

 also, an enormous mass of notes was collected, and on 

 February 4th, 1868, having seen his great work on 

 Variation under Domestication published, Darwin 

 was able to make the entry in his diary, 'Began 

 work on Man.' 



As was usual with most of his works, Darwin 

 underestimated the time required to complete it. 

 Through all the years 1867 '68, '69 and 70 we find 

 the entries in his diary ' working at Descent of Man,' 

 and only early in the year 1871 was the book finished. 

 His original plan of compressing his notes on the 

 expression of the Emotions into a chapter at the end 

 of the book proved to be impracticable, and the 

 material was reserved for a new work. This work, 

 The Expression of the Emotions in Man and Animals, 

 was commenced directly the Descent of Man was out 

 of hand, a rough copy was finished by April 27th, 

 1871, but the last proofs were not corrected till August 

 23rd, 1873. 



In dealing with the question of the origin of the 



