vl PREFACE 



original notes from my experience gathered in the meantime at 

 Woods Hole, Naples and Roscoff. 



For many problems in embryogenesis, the study of the living 

 egg alone does not suffice or is impossible to make. Study of the 

 fixed egg thus becomes a necessary supplement or is mandatory. 

 Methods for the preparation of the fixed egg are therefore indis- 

 pensable for the experimental embryologist. Hence, a large 

 section of this little book is devoted to these methods. 



The methods detailed are all known to me through years of 

 experience. Some of my own devising have given preparations 

 whose superlative beauty has elicited most favorable comments 

 from experts in cytology both in Europe and in America. I 

 may point out that during more than twenty-five years I have 

 used these methods with unvarying success on animal cells, from 

 Protozoa to man included. They are therefore of value to 

 cytologists generally. 



Since the book is not encyclopedic in its scope, it carries no 

 literature list. Some few references to original papers are 

 added at the ends of sections. These references contain addi- 

 tional citations to literature. 



I wish to express my best thanks to Dr. L. V. Heilbrunn who 

 so kindly consented to correct the proof. 



E. E. J. 



Station Biologique 

 DE Roscoff 

 April, 1939. 



