JPreface 



In this book I set forth fundamental methods for the use of 

 eggs and spermatozoa of marine invertebrates in experimental 

 investigation. In addition to methods concerning marine 

 gametes generally, I give some that refer especially to those eggs 

 and spermatozoa that are most commonly employed; these 

 methods, however, are themselves so general that they apply 

 equally to gametes of the same species both in American and in 

 European waters, and to those of closely related species. The 

 book thus gives methods for any species of marine gametes used 

 in laboratory investigation. 



The book in no wise aims to be one of recipes for individual 

 experiments or a catalogue of all methods in use. Instead, it 

 purposes to pass on to the reader what I have learned during 

 my years of experience with marine eggs. The individual experi- 

 ment capable of being repeated at will depends very strongly on 

 the adherence to some general rules. These I here set forth. 

 They will serve both as the starting-point for one who for the 

 first time enters the field of experimental embryology, and as a 

 basis for the specialist whose work demands individual extension 

 of methods. 



The suggestion to make my knowledge of methods for success- 

 ful experiment on marine eggs more generally available came 

 from a number of fellow-workers. The strongest impetus was 

 received from my friends, Mr. Ware Cattell and Dr. L. V. 

 Heilbrunn. In answer to their insistence I published some years 

 ago a series of articles in Mr. Cattell's ^'Collecting Net.'' In the 

 years before these articles appeared I had had at Woods Hole 

 much experience in aiding investigators who frequently sought 

 my advice. In this wise I came to know more surely what are 

 the chief needs of those who work on marine eggs. Since the 

 publication of these notes many investigators both in America 

 and in Europe have requested their re-issue in a more available 

 form. In meeting this demand I have made additions to the 



