8 AN INTRODUCTION TO MODERN GENETICS 



above, may serve as some excuse; the need has arisen primarily because 

 the different kinds of biological cobblers have in the past stuck too 

 closely to their lasts. I want to urge that the connection between 

 genetics and the other branches of biology, such as cytology, em- 

 bryology, the study of evolution and of the biochemical nature of cell 

 constituents, is much closer than is often admitted, and that the boun- 

 daries between these subjects deserve less attention than is usually paid 

 to them. 



It is probably inevitable that many errors, both of omission and 

 conmiission, will be found in a book which, like this one, attempts to 

 survey the present state of affairs in a large and rapidly expanding 

 branch of science. I have, however, been extremely fortunate in receiving 

 mosc generous help from many friends and colleagues, who have, I 

 know, saved me from many errors and very gready contributed to any 

 merits this book may possess. I should like in particular to express my 

 gratitude to the following, who have read and criticized the whole 

 or large parts of the work: C. B. Bridges, C. D. Darlington, Th. 

 Dobzhansky, C. Stem, M. Whittinghill. 



C. H. W. 



CAMBRIDGE 

 1938 



