158 



KARL PETER. ,,Grundlagen einer funktionellen Embryologie, eine biolo- 

 gische Studie", Johann Ambrosius Barth/Verlag/Leipzig. 170 Seiten. 



In this book the author treats a rather neglected aspect of embryological 

 development, viz., the problem of the functional unity, which a developing 

 organism forms at every moment of it life history. The author divides the 

 problem into two main questions, viz., the factors which enable the develop- 

 ment of the form, and those which guarantee the maintenance of life. 



After a separate treatment of both questions, their interrelations are analysed, 

 while in a next chapter the factors, which guarantee the maintenance of life, 

 are studied in the various groups of Vertebrates. 



Then the plasticity of the developing organism is discussed, a plasticity 

 which enables the embryo to adapt itself to the gradually changing external 

 and internal conditions. Here the author mentions the power of regulation, 

 the resistance against poisons, the power of regeneration, the dependent and 

 independent development of parts of the organism at successive stages of 

 development, etc. 



A special chapter has been devoted to a comparison between larval and 

 adult life, in order to show the special demands which the embryological 

 development makes for the maintenance of life. 



In his book ,,Die Zweckmassigkeit in der Entwicklungsgeschichte", which 

 appeared in 1920, the author already drew the attention to the efficiency 

 of all embryological processes, which are aimed at the requirements of the 

 adult state. This ,, final" view forms a very valuable complement to the com- 

 monly studied causal and genetical aspects of development, as here we 

 approach the problem from a quite different point of view. Although these 

 various points of view are complementary fields of science, they really 

 support our general understanding of the problems of development and life. 

 We will, therefore, express our gratitude to the author having given a more 

 systematical consideration of the whole development seen in the light of 

 efficiency in this book. This book will certainly stimulate the interest in 

 this branch of science. We are already looking forward with interest to 

 the second part of this study, which will deal with the relations between the 

 various embryological processes and the functions of the various organ 

 systems. 



This book is rather simply executed as direct consequence of the great 

 difficulties which had to be overcome in these years in Germany so shortly 

 after the second world war. We hope that the second part will be printed 

 on better paper and will be more richly illustrated. The illustrations themselves 

 are good, but do not always show to full advantage on this paper. 



The book contains an extensive list of literature, which gives mainly 

 somewhat older literature. 



P. D. NIEUWKOOP. 



