Preface 



IX 



stern judge." His book, " Breeding and the Men- 

 delian Discovery," published in 1911, is a clear 

 summary of his work and thought on the prob- 

 lems he had himself investigated. From 1905 to 

 1911 he held the post of Senior Demonstrator 

 and Lecturer in Zoology at the Koyal College of 

 Science. It was at this period that he came in 

 contact with Samuel Butler, first through " Ere- 

 whon," then through " Life and Habit," and his 

 conception of evolution underwent a profound 

 change. In his lectures thenceforward he, traced 

 the growth of the theory from the Greek philo- 

 sophers through Buffon and Lamarck up to Darwin, 

 and the philosophical bearings of the theory became 

 for him its paramount interest. 



In 1911 he accepted the newly created post of 

 Lecturer in Genetics at the University of Edinburgh. 

 The University Experimental Farm at Fairslacks 

 under the Pentland hills gave him a new field for 

 his investigations in heredity. His friendly asso- 

 ciation with Professor Cossar Ewart helped to make 

 this post the happiest he had held. He had already 

 become deeply interested by Bergson's thought 

 when Bergson himself came to Edinburgh to give 

 the Gifford lectures in the summer of 1914. He 

 met and talked with Bergson, had the pleasure of 

 introducing him to Butler's theories, and the rare 

 experience of talking about his own speculations 

 to a thinker who saw their drift and value. 



At the opening of the war in July, 1914, he was 

 in America, lecturing to the Graduate School of 

 Agriculture at the University of Missouri, Columbia, 

 Missouri. As a result of his lectures the University 



