142 THE COMING [CH. 



Owing to delays caused by the preparation and 

 publication of these books and frequent interruptions 

 from sickness, the work on variation did not appear 

 till 1868. It was a very extensive piece of work in 

 two volumes, and, at its end, Darwin tentatively 

 propounded a hypothesis to account for the facts 

 of Heredity and Variation to which he gave the 

 name of ' pangenesis.' 



Charles Darwin had reached the age of fifty, when 

 he wrote the Origin of Species. At a very early 

 period in his career, he had resolved that he would 

 never start a new theory or revise an old one after 

 he was sixty ; as he used laughingly to say, ' I have 

 seen too many of my friends make fools of themselves 

 by doing that/ But as he approached this ' fatal age,' 

 one more subject of a theoretical and highly con- 

 troversial nature remained to be dealt with, namely, 

 the question of the application of the theory of 

 natural selection to man, both as regards his physical 

 structure and his intellectual and moral charac- 

 teristics. 



Darwin tells us that in 1837 or '38, as soon as he 

 had become t convinced that species were mutable 

 productions,' he ' could not avoid the belief that man 

 must come under the same law 140 .' From that time, 

 he began collecting facts bearing on the question. 

 As each of his children was born, he examined closely 

 the signs of dawning intelligence, and made notes of 



