This volume includes nine reports presented at a conference or symposium on embryology held in 1947. The contributors are experimental embryologists working on problems of potentialities of invertebrate and amphibian eggs, as well as of early larval stages of Amphibia and of the chick blastoderm.
The studies reveal, above all, the great progress which has been made since the early days of the theory of "developmental mechanics" (Roux), with its concepts of relative fixity of the potencies within the egg or of subsequent development. As pointed out by one of the contributors, answers to morphologic questions are now being sought and established which would have been meaningless in the classic period of descriptive embryology (Rudnick). The reports and discussions deal with intraovular differentiation (ooplasmic segregation), fertilization, cleavage, the significance of the cell membrane, biochemical differentiation (early activities of enzyme systems), mass movements and form changes, transplantations and regeneration.