INTRODUCTION 



The material of this "Experimental Emhryology" represents many years of the most 

 Intense research on the part of Innumerable embryologists, from all parts of the world. 

 The author disclaims £iny originality except In those sections relating specifically to 

 his particular investigations. The book is a compendium of data, directions, and ref- 

 erences not generally found in textbooks, but information which is necessary in train- 

 ing the prospective experimental embryologist in the fundamentals of this relatively 

 new and dynamic field of research. 



There are contained herein some 50 separate experimental procedures, from Andro- 

 genesls to Xenoplastic Grafts, all of which have been tested in the course "Mechanics 

 of Development" given for the past nine years at New York University. The present, 

 completely rewritten book incorporates all the improvements in the various techniques 

 that have come to the author's attention. Each procedure is presented as foundation- 

 al to some basic concept so that the qualified graduate student may be stimulated to 

 pursue further research in the field. The approach is entirely ejcperimental ; the 

 subject matter is exclusively the embryo . 



The organization of each exercise is based upon the general plan of a publish- 

 able scientific manuscript. The usual historical background is omitted, and the 

 discussion (if any) is limited because this is the function of related textbooks. 

 The reference list contains only the most recent and pertinent papers, and certain 

 review articles. Only occasionally there are included papers more than 15 years old, 

 and these because they have been established as classics within the field. It is 

 felt that interested investigators can acquire a complete bibliography through the 

 references given. 



It is recommended that the student's report include the following, space for 

 which Is generally provided in each exercise: 



a. Experimental procedure: Any modifications of the procedure as outlined. 



b. Experimental data: This section must be complete in every detail. 



c. Discussion: This should be baaed upon "b" above. 



d. Conclusions: These should be based entirely upon the findings of the 



student. 

 9. Eeferences: Only new references which are not included In this exercise. 



It would be Impossible for any student, under any conditions, to complete the 

 work outlined In this book during a single academic year. There are three solutions 

 to this matter, all of which have been tried in our laboratory and any of which is 

 satisfactory: 



a. Assign a new procedure for each of the regular weekly laboratory sessions. 

 This is a very heavy assignment and the student would necessarily spend 

 more than the usual four hours per week in the laboratory. The plan has 

 the advantage of making it simpler for the Instructor to anticipate the 

 needs of the entire class, from week to week. He can often schedule the 

 procedures in such a way that they follow in a natural sequence and often 

 conveniently overlap. The major disadvantage is that the student acquires 

 only a passing acquaintance with the various techniques and is apt to as- 

 sume that he is master of all of them. 



b. Select a logical series of experimental procedures designed to be com- 

 pleted during the first semester, and progressing from the gross to the 

 microscopic, the ci-ude to the refined, the simple to the complex. There 

 is no attempt to cover the entire gamut of techniques. The responsibility 

 of representative selection falls on the instructor, but the student Is 

 quite thoroughly grojxnded in the basic procedures, and is thereby quali- 

 fied later to pursue Independent investigation. This has been the most 



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