viii PREFACE 



knowledge. At the present time there are, for example, increasingly well 

 beaten paths between genetics and embryology, between endocrinology 

 and cancer research, between cancer research and bacteriology, between 

 bacteriology and genetics. It is a major purpose of this book, by gather- 

 ing together the fundamental knowledge about the mouse from several 

 fields of study, to make it easier for the research worker using mice as his 

 experimental material to traverse these interconnecting paths of science. 



The preparation of the book has been financed by a grant from the 

 John and Mary R. Markle Foundation. This generous support has made 

 possible the conduct of several pertinent research projects and the 

 preparation of many original photographs and drawings. The embryo- 

 logical studies described in Chapter i have also been aided by a grant from 

 the Alexander Dallas Bache Fund of the National Academy of Sciences. 

 In the preparation of their material the authors have been ably assisted 

 by the following persons: Miss Olive Bartholomew, preparation of 

 embryological and histological sections; Miss Bernette Bohen, drawings; 

 Mr. Joshua Burnett, tabulation of linkage data; Dr. Elizabeth Chase, 

 histological sections; Dr. Katrina P. Hummel, photography; Mr. Arthur 

 Lieberman, bibliography; Mr. John Mowat, photography and construc- 

 tion of apparatus; Mr. William Payne, photography; Miss Ella Rowe, 

 preparation of sections; Miss Elizabeth Keucher, assistance in preparation 

 of the index. Prof. C. H. Danforth has made valuable suggestions in 

 regard to several parts of the text. 



In conclusion, the editor would like to express his appreciation to the 

 other members of the Laboratory Staff for their continued cooperation and 

 for many valuable suggestions, and to Dr. C. C. Little for his hearty 

 support and, in a broader sense, for the wise direction in a large measure 

 responsible for the friendly atmosphere so essential for successful 

 collaboration. 



George D. Snell, Editor 



Roscoe B. Jackson Memorial Laboratory 

 Bar Harbor Maine 



