g Introduction 



review papers are cited which help summarize results in particular fields. 

 No one person, and certainly not the present writer, is competent to give 

 a thoroughly informed and authoritative judgment on the relative worth 

 of the wide variety of investigations here discussed. It is hoped, how- 

 ever, that one service of the book will be to introduce its readers to the 

 subjects of these studies even though in some cases a piece of work can 

 be given little more than mention. 



Since there is no sharp line between morphogenesis and its neighbor- 

 ing fields of morphology, physiology, genetics, and the chemical and 

 physical sciences, much of the advance in it will doubtless be made, as 

 in the past, by men whose chief concern is with one of these other disci- 

 plines; but as morphogenesis becomes better organized and as more op- 

 portunities for training and research in it are offered by our colleges and 

 universities, there will be more students whose primary interests are 

 directed to it. More than other biological sciences, perhaps, morpho- 

 genesis will need to maintain close contact with a wide variety of other 

 fields, for few can hope to be competent in its entire area. To develop 

 this comprehensive subject fruitfully will require the active cooperation 

 of many sciences, and by this means the morphogenetic point of view 

 can thus help to integrate all of biology. 



