173 



organ systems as derivatives of special germ layers so that the attention of the 

 reader is focussed on the development of each organ system. 



The large number of illustrations markedly facihtates the reading of the 

 text which is moreover written in a semi-popular form so that this book is 

 of great value for teaching purposes. For the embryology student it moreover 

 gives many valuable data on each successive phase of development so that 

 we can recommend this book to a wide circle of readers. 



The extensive glossary of embryological terms at the end of the book forms 

 a very valuable chapter and may serve as an example for other textbooks. 

 The fairly extensive bibliography for frog embryology finally facilitates and 

 stimulates the reading of the original Hterature. 



It is a pity that some of the diagrams, e.g. in the chapter on early organo- 

 geny, are too strongly simpHfied, which may lead to confusion at certain points. 

 It might moreover be preferable to number the figures so that one can refer 

 more easily to them in other parts of the text. These remarks, however, form 

 only a suggestion for improvement of a new edition. This textbook as a total 

 forms a very valubale unit in the series of monographs on development of 

 individual forms such as Lilhe's Development of the chick, etc. 



P. D. NIEUWKOOP 



„ENTWICKLUNGSPHYSIOLOGIE" 

 1952 



by L. V. Ubisch F. W. Peters 



85 pp. with 127 figs Berlin 



This small monograph only forms an introduction into the field of develop- 

 mental physiology and gives only some principle facts and problems against 

 the background of the authors vision on development given in the later 

 chapters of this booklet. A number of characteristic forms is chosen among 

 invertebrates and vertebrates, forms on which the problem of "determinative" 

 and "undeterminative" development is illustrated, after which the classical 

 concepts of determination, organization and induction are discussed. After a 

 discussion of Child's gradient-theory and the role of special cell-constituents, 

 the author emphasizes the significance of the colloidal state of the so called 

 "ground-plasm". This ground-plasm should be under the influence of three 

 gradient systems along the three axes of the embryo. The genes operate in 

 this three-dimensional gradient-system of the plasm colloids and activate the 

 development of special organ-systems in a mutual harmonic topography and 

 proportion. 



Although the train of thought of the author is quite interesting, the hypo- 

 thesis to which it leads is very general and rather simplistic. Too few basic 

 facts are, however, known than that general theories might bring us much 

 further to an understanding of the basic principles of hfe. 



P. D. NIEUWKOOP 



..ELEMENTS OF CHORDATE ANATOMY" 

 1953 

 by Ch. K. Weichert McGraw-Hill Book Comp.. Inc. 



451 pp. with 256 figs in text New York-Toronto-London 



price: $ 5.50 

 This text book is a condensation of "Anatomy of the Chordates" by the 



