PREFACE 



This book owes its inception to informal 

 gatherings, seminar fashion, of a small group 

 of embryologists who for several summers 

 (1933-1940) periodically retired from the 

 busy scene of the Marine Biological Labora- 

 tory at Woods Hole to the peace and quiet of 

 the sand dunes along the northern coast of 

 Cape Cod near Barnstable. With the sea as 

 background and the sand for a blackboard the 

 "Sandpipers" (a name derived from our alert 

 and ever-searching avian companions on the 

 beach) discussed at length the problems of 

 development and groped for a better under- 

 standing of the mechanisms of embryogenesis. 



To those who took part in them, these group 

 discussions were a valuable experience. The 

 satisfaction that came from the exchange and 

 conciliation of conflicting views arovised our 

 urgent desire to broaden the experience and 

 share it with a far wider circle of biologists. 

 Jointly the hope was engendered that future 

 accounts of embryological knowledge would 

 emphasize the dynamic and causal aspects of 

 embryogenesis rather than mere description 

 and seriation of developmental stages, a prac- 

 tice still too common in the lecture room and 

 textbook. To transcend descriptive embryol- 

 ogy and blend experimental data with "Beob- 

 achtung und Reflexion" was clearly set as 

 our goal. Only by such an account could 

 younger students be challenged and influ- 

 enced in their future research and teaching in 

 this important field. Above all, the need was 

 felt for helping to overcome the trends of over- 

 specialization by encouraging a wider, inter- 

 disciplinary perspective and by integrating 

 the ever-growing volume of accumulated in- 

 formation into a broad conceptual framework. 

 The need for a well-balanced account of the 

 developmental process was apparent. But how 

 was such a plan to be translated into action? 



It was evident from the start that the sub- 

 ject matter had grown in volume and intric- 

 acy to the point where it seemed futile for any 

 one individual to attempt to cope with such a 

 task. The alternative was to call on many 

 specialists for authoritative presentations of 

 their respective subjects. We realized that by 



this procedure much of the desired unity and 

 integration would be sacrificed, and the pres- 

 ent volume bears plainly the stigmata of 

 these imperfections. Yet, despite our hesita- 

 tions on this score, the three of us, encouraged 

 by the urging of many colleagues, outlined 

 in 1947 a plan for a collaborative work on the 

 analysis of the developmental process. 



The original blueprint contained an out- 

 line and table of contents of the subject mat- 

 ter to be covered in hierarchical divisions, as 

 well as specifications for their serial order and 

 relative proportions. For this basic pattern the 

 three Editors take full responsibility. Yet, 

 within that general frame, the individual con- 

 tributors were given no more than a general 

 topical guide that left full scope to their per- 

 sonal preferences in the choice of samples, 

 style, and manner of presentation, the only 

 provision being that they conform to the gen- 

 eral spirit and objectives of the undertaking. 

 The guiding aims were expressed to them in 

 the following commentary. 



The purpose of this book is to present a modem 

 synthesis of our knowledge of the principles and 

 mechanisms of development. In these days of rap- 

 idly expanding information, it becomes increasingly 

 difficult to keep perspective. It is urgent, therefore, 

 that this book provide not just another source of 

 information, but that it view the phenomena of 

 development from a common perspective so that 

 the reader may recognize the great main lines and 

 inner coherence of the field above the multiplicity 

 of often unrelated details of which the field seems 

 composed when viewed too closely. There is perhaps 

 need for a comprehensive compilation of all the 

 experimental data that have been amassed in the 

 field of Experimental Embryology in the past. 

 However, this book is not intended to fill that need. 

 It is not to be a handbook. It does not aim at a com- 

 plete and exhaustive review of the field. Each con- 

 tributor is asked to make a critical and, in a way, 

 subjective selection of the special field to be covered 

 in his article. He should give a clear outline of the 

 general problems, concepts, and lines of investiga- 

 tion of his topic and illustrate them with selected 

 examples from experimental data. Only those ex- 

 periments should be presented that are crucial and 

 analytically strong and convincing. Repetitiveness 



