viii Preface 



the exception of these portraits and of figures 1, 

 2, 3, 4, 14, 15, 35, 39, and 64, are all from my own 

 laboratory and were photographed or drawn by 

 Mr. Julian A. Carlile whose competent help has 

 certainly greatly enhanced whatever value the 

 book may have. My sincere thanks are due him 

 and other members of the technical staff of the 

 Rockefeller Institute for their unfailing coopera- 

 tion. I should like to thank Dr. James Bonner 

 for the photographs used in figure 35 and John 

 Wiley and Sons for permission to republish figure 

 22, the original of which I furnished them in 1937. 

 Pictures taken from periodicals and from older 

 books carry their acknowledgments in the text. 

 The bibliography at the end of the book is intended 

 to cover the major contributions in the field of 

 Plant Tissue Cultures and to contain in addition 

 some collateral material from related fields suffi- 

 cient to suggest to the reader possible interrela- 

 tions. Corrections, suggestions, and criticisms 

 will, of course, be welcomed. 



With this brief introduction, I turn my offspring 

 over to the good graces of a critical and exacting, 

 but I trust understanding, public. 



Princeton, New Jersey, 

 September, 1942. 



