The organization of the book is rigorously logical, and the style is clear. 

 It is impossible to review the book in detail: this will be the task of specialists 

 in the field. One thing may be mentioned: the book opens with a chapter 

 devoted exclusively to theoretical aspects, such as the methods of comparative 

 embryology, criteria of homology (Remane), the biogenetic law (recapitul- 

 ation theory), the "biometabolic modes" (Osche), and questions of ter- 

 minology. 



The book is exceedingly well produced, and illustrated with numerous 

 beautiful line drawings. Many of these are original, but the ones taken from 

 other sources were all redrawn, leading to a very satisfactory unity of style. 

 The bibliography is restricted to important works. The book is concluded 

 by an author index and a detailed subject index. 



14 DYNAMICS OF DEVELOPMENT: EXPERIMENTS 



AND INFERENCES 



Selected papers on developmental biology 



1968 



By P. A. Weiss Academic Press 



624 pp., 133 figs.. 2 tbs., 4 pis. New York - London 



In this book the author has brought together 24 of his papers so far 

 scattered over a variety of media, some of which are not easily accessible. 

 As he says in his foreword, his main motive in making this compilation has 

 been that he considers "the cardinal function of these papers in their con- 

 junction to be their contribution to the emergence of a unified understanding 

 of the dynamic order of living systems." Major features of Weiss' writings 

 produced during half a century have been, first, the conviction that the 

 problems of development should be approached from many directions, and 

 secondly the continuous effort to fill theoretical concepts with more concrete 

 meaning. 



The papers have been grouped into five sections, entitled respectively 

 "On basic principles", "On differentiation", "On growth and aging", "On 

 form and formative processes", and finally "On the dynamics of the nervous 

 system". Within each section the order of the papers is logical rather than 

 chronological. 



The papers are reproduced in facsimile, complete with the original illus- 

 trations and running titles (the latter sometimes being meaningless in the 

 context of this book). Three papers bear no date of publication; the rest date 

 from as far back as 1933 until 1967. 



The book is concluded by a brief topical index referring to chapters. 



15 CELLULAR DIFFERENTIATION 



1968 

 By J. R. Whittaker Dickenson Publishing Cy., Inc. 



Dickenson Ser. on Contemp. Belmont, Calif. 



Thought in Biol. Sci. Price: 21 s.; $ 2.50 



112 pp., 52 figs., 21 tbs.. 2 pis. 

 (paper-bound) 



This booklet forms part of a series of "books of reading". The aim of the 

 series is to confront the student right from the beginning with significant 

 original publications in a given field. The eleven papers in the present volume 

 represent a well-balanced choice, highlighting significant aspects of the 

 problem of differentiation. They are grouped in four sections, each with a 



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