v i FOREWORD 



of the minutiae. At the present time certain principles are known to be in- 

 volved in the determination of the pattern of development. It is far more 

 important for a student to become acquainted with these principles than for 

 him painfully to cram his head full of a thousand and one names he fears he 

 must have in order to face an examination successfully. For an intelligent 

 student, learning should be not a tedious ordeal but an exciting adventure. 

 And embryology properly taught should appeal to everyone who is interested 

 in knowing how he came to be as he is. 



Textbooks can mean a great deal to the development of a science, and 

 I am confident that this book will bring new zest to the teaching and learning 

 of embryology. Written by one of the leading experts in the field, it is never- 

 theless simple and understandable throughout. I found many of the chapters 

 thrilling. The embryology of the future will no doubt be strongly influenced 

 by men who got their first inspiration from Barth's Embryology. 



L. V. Heilbrunn. 

 University of Pennsylvania 

 March 16, 1949 



