Book - Text-Book of Embryology (1921)

TEXT-BOOK OF EMBRYOLOGY

BY

FREDERICK RANDOLPH BAILEY, A. M., M. D.

FORMERLY ADJUNCT PROFESSOR OF HISTOLOGY AND EMBRYOLOGY, COLLEGE OF PHYSICIANS AND SURGEONS (MEDICAL DEPARTMENT OF COLUMBIA UNIVERSITY)

AND

ADAM MARION MILLER, A. M.

PROFESSOR OF ANATOMY, THE LONG ISLAND COLLEGE HOSPITAL

fourth editon

WITH FIVE HUNDRED AND THREE ILLUSTRATIONS

COPYRIGHT, 1921, BY WILLIAM WOOD & COMPANY.

Preface to the Fourth Edition

In the present edition the plan of the book has been modified in certain respects. The chapter on the cell has been omitted because in the opinion of the authors the previous training of the student who commences the study, of the embryology of vertebrates has been sufficient to bring to his attention the salient features of cell organization. In former editions the early processes of development, viz: cleavage, gastrulation, and mesoderm formation, were treated as topics in separate chapters. The present plan comprises the treatment of the early stages in succession in a given animal form; individual chapters are devoted to Amphioxus, the frog, the chick, and the mammal. This change has been made because it is our opinion gained from experience in teaching that the student acquires a better understanding of the development of the germ layers by following the processes as a continuous series in a given animal. A number of old illustrations have been replaced by new figures the sources of which have been duly credited.

Apart from the insertion of the chapter on foetal membranes the second part of the book, comprising organogeny, has been revised only in so far as the results of recent investigation have modified the ideas expressed in the previous edition.

We wish to express our appreciation of the helpful criticisms of our colleagues and other friends.

THE AUTHORS. JULY, 1921.