The first observations of embryonic development date 

 back 2,500 years; however, the onset and development of 

 embryology as a science is connected with the general 

 progress of the natural sciences in the eighteenth and 

 nineteenth centuries. There are three main stages in the 

 history of embryology. The period of the substantiation of 

 the theory of epigenesis, making possible the existence of 

 embryology, is connected with the Russian academician 

 K. F. Wolff. The period of the discovery of the embryonic 

 layers, when the prerequisites for comparative embryology 

 appeared, is the period of activity of the Russian 

 academicians Kh. I. Pander and K. M. Baer. Finally, the 

 period of the creative development of embryological problems 

 in the light of Darwin's work is inseparably united with 

 the Russian investigators A. 0. Kovalevsky and I. I. Mechnikov 

 and the brilliant zoologists who followed their footsteps. 



The present book reviews the first two periods of the 

 history of embryology, including the epoch directly 

 preceding the scientific activity of A. 0. Kovalevsky and 

 I. I. Mechnikov. The history of Russian embryological 

 investigations, from the beginning of comparative embryology 

 to the present time, is embodied in the contents of the 

 books discussed here. One is dedicated to the history of 

 embryology of invertebrates and another book elucidates the 

 history of the embryology of vertebrates. 



At the time of writing the present book, no work of 

 Wolff or Baer had been published in Russian except for the 

 incomplete and inaccurate translation of the second part of 

 the first volume of Baer's UBER ENTWICKLUNGSGESCHICHTE .5 

 In 1950, in the academic series "Klassiki nauki," the 

 translation of Wolff's "Theory of Generation" appeared, 

 as did the translation of the two volumes of Baer's "History 

 of Animal Development" in 1950 and 1953. An article by 

 Gaissinovich 6 (in an appendix to Wolff's book) clearly presents 



5. K. M. Baer, IZBRANNYE RABOTY (Selected works), from the 

 series KLASSIKI ESTESTVOZNANIYA, translated with 

 comments and preface by Yuri A(leksandrovich) Filipchenko 

 (Moscow: GIZ, 1924), 114 pp. 



6. A. E. Gaissinovich, "K. F. Wolff and Studies on Develop- 

 ment," in an appendix to K . F. WOLFF: THEORY OF 

 DEVELOPMENT (Moscow: Akademii nauk, 1950), pp. 363 - 477 



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