166 



living material must be based. The author tries to show in this essay on 

 development how at least three principles seem to play a role in the structural 

 organisation of living matter, viz. growth, morphogenetic movement and dif- 

 ferentiation. External and internal limiting factors influence the individual roles 

 of these processes in the development of structural patterns. Polarity and its 

 determination also directs the achievement of structural pattern formation. 

 This takes place inside a single cell as well as in cell aggregates, multicellular 

 organisms and even in colonies of individuals. A comparison with the properties 

 of crystals forms an interesting analogy as a possible bridge between the 

 biological and the physico-chemical appreciation of the problems of life, which 

 might lead according to the author to a "micro-structure theory". The text 

 has been enriched with carefully selected, excellent illustrations, so that it is 

 a pleasure to read this interesting essay. The bibliography includes unfor- 

 tunately only a few references in foreign languages, which gives the wrong 

 impression as if this approach of the problem of life is mainly made in the 

 anglo-american part of the world. 



P. D. NIEUWKOOP 



, .CYTOCHEMISTRY" 



(A Critical Approach) 



1953 



by J. F. Danielli John Wiley & Sons, Inc.. New York 



139 pp. with 8 figs in text Chapman 6 Hall, Ltd.. London 



and 12 photo-plates price: $ 4. — 



This book will by no means be called a textbook on cytochemistry, since 

 according to the author "the body of agreed facts on cytochemistry is still 

 completely insufficient"; it only represents a slightly enlarged version of a 

 series of lectures given in 1949 at the University of Chicago. 



In the introduction of this book the elementary techniques are treated 

 critically in order to show their applicability and their restricted value. In 

 the following chapters some special cytochemical problems and the techniques 

 used in their analysis are discussed more in extenso. while at the end a future 

 outlook in cytochemistry is given. 



The author's critical approach to this young branch of biology might have 

 great influence on its further growth, since it shows how great difficulties 

 have to be overcome before reliable results can be obtained. We, nevertheless, 

 think that the often still highly speculative working-hypotheses put forward 

 in this book, do not always actually contribute to is in general high standard. 



For the field of embryology where the biochemical studies have been up 

 till now so unsuccessful by the undifferentiated character and the small size 

 of the material concerned, cytochemistry might offer new and very important 

 methods of analysis. Here it will, however, be a first condition in the analysis 

 to proceed very critically step by step in order to prevent serious disappoint- 

 ments, and to avoid a further discredit of the field of embryology among the 

 present and future young generations of scientists; put in the words of the 

 author "the promise of the field of cytochemistry, however, will only be 

 fulfilled if cytochemistry is used as a rigorous technique by an adequately 

 trained staff". 



