PREFACE 



deplorable. Opposition to Lysenko should not be based on the criti- 

 cism of his scientific views, weak and naive though they are, but on 

 the fact that he has achieved his prestige by conniving at the murder 

 of his scientific adversaries rather than by argument and discussion 

 and that he acts as an arbitrary dictator over other biologists, sup- 

 pressing freedom of discussion and research. 



In addition to acknowledging the assistance of those who have 

 helped directly with the present volume, I would like to express my 

 thanks and affection for my teachers whose influence, I hope, is 

 apparent in my treatment of the problems of genetics and cytology. 

 Principal among them are T. H. Morgan, Calvin Bridges, R O. Dodge 

 and A. H. Sturtevant To them, and a host of others, I am sincerely 

 grateful. 



I am grateful to Dr. Jack Schultz for his helpful criticism of the 

 manuscript. 



Finally, my gratitude to Mr. James D. Veron for his continued 

 interest and constant encouragement. 



Carbondale, Illinois 



November 5, 1948 C. C. L. 



ix 



