PREFACE 



During the summer of 191 1, a course of lectures on 

 heredity and allied topics was given at the University of 

 Chicago, under the auspices of the biological departments. 

 The purpose of the course was to present the recent develop- 

 ments of knowledge in reference to variation, heredity, and 

 evolution, and the application of this new knowledge to 

 plant, animal, and human development and improvement. 



The lectures were not intended for those trained in 

 biology, but for a general university audience, interested 

 in the progress of genetics as a matter of information rather 

 than of study. The lecturers, therefore, did not address 

 themselves to their colleagues, and did not attempt to 

 include any considerable amount of new material. It is 

 believed that a much larger audience than the one originally 

 addressed might be interested in this summary of results 

 in one of the important and recently cultivated fields of 

 biology, and therefore this volume has been published. 

 It is hoped that it may perform a service not only for those 

 interested in biology as a field outside their own experience, 

 but also for those biologists whose w^ork deals with other 

 phases of biology. 



The lectures were given by five lecturers, with no oppor- 

 tunity to relate the lectures to one another other than as 

 suggested by the assigned titles. It is inevitable that there 

 should be more or less overlapping of statements, and no 

 attempt has been made to avoid this. Each lecture, 

 therefore, is complete in itself, as it was delivered. 



