access to the specialist journals in this field. It should be stressed, however, 

 that many of the contributions presuppose a good acquaintance with con- 

 temporary physics and mathematics. The reader may obtain a more detailed 

 picture of the sort of problems discussed at these meetings from an article by 

 Waddington in Nature (vol. 218, no. 5141, pp. 525-527, 1968). 



One of the major aims of these Symposia was "to decide what are the type 

 of questions which in biology might correspond to the kind of questions dis- 

 cussed by theoretical physicists in their field" (Waddington, in vol. 2). 



The contents of all three books are extremely varied, ranging from rigorous 

 physics and mathematics to the tentative expression of personal thought, with 

 excursions into semantics and metaphysics. There are formal presentations 

 but also what may be called attempts at thinking aloud. Also included is a fair 

 amount of personal comment and exchange, and some correspondence issuing 

 from the Symposia. Part of the contents consists of reprints of previously 

 published material, or of material published elsewhere since the Symposia were 

 held. 



The books are attractively produced at a very reasonable price. They are 

 adequately illustrated and have author and subject indexes. 



5 A SURVEY OF EMBRYOLOGY 



1968 

 by F. G. Gilchrist McGraw-Hill Book Comp. 



426 pp., 234 figs., 2 tbs. New York - London etc. 



Price: 96 s.; $ 9.95 



In this text-book for undergraduates the author has aimed at integrating 

 descriptive and analytical embryology, in which he has succeeded admirably. 

 The "backbone" of the book is the descriptive account of the early develop- 

 ment of amphibians, birds, and mammals, followed by an account of verte- 

 brate (mainly mammalian) organogenesis by organ systems. This main part 

 is preceded by an historical introduction (which clearly brings out the major 

 problems of embryology and the way in which they have arisen), and three 

 good basic chapters dealing respectively with the nucleus in development, the 

 cytoplasm in development, and general features of development (comparative 

 gametogenesis, fertilization, cleavage and gastrulation, supplemented by a 

 section on phylogeny). In these four chapters, which occupy about a quarter 

 of the book, much of the subject matter treated relates to invertebrates and 

 even to unicellular organisms. 



Throughout the book (also in the main part) a surprising amount of 

 modern experimental and biochemical work has been smoothly integrated in- 

 to the text. This material is presented clearly and succinctly without going 

 too much into details. The author's style is simple but by no means dull, and 

 should appeal to young students. Of particular importance is the emphasis on 

 the embryo as a whole arising through epigenetic processes. 



The numerous drawings, all made by the author in a uniform style, are 

 highly successful and strike the correct balance between realism and sim- 

 plification. All chapters end with an excellent list of selected readings. At the 

 end of the book there is a very useful annotated bibliography of sources of 

 embryological information, covering books, monographs, paperback texts, 

 journals, symposia, and review publications. The book is well produced and 

 is concluded by a combined author and subject index. 



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