introduction sets the theoretical stage. The main bulk of the book consists of three long 

 chapters. In the first (Epigenesis: the analytic approach) animal embryogenesis is dis- 

 cussed in terms of four large categories: (1) the embryogenetic substrate (cells, extracellu- 

 lar components, and the fertilized egg), (2) cell division, (3) cell diversification (in which 

 a very useful distinction is made between cell transformation and cell differentiation), 

 and (4) morphogenetic processes, and their interactions with the other three categories. 

 The next chapter (Epigenesis and ontogenesis) then takes up the same subject stage-wise 

 and in a broad range of taxa. The topics discussed consecutively are cleavage, blastulation, 

 gastrulation, larva formation, physiological events, and biochemical events. The last 

 chapter is called Epigenesis and phylogenesis. It first discusses the main tenets of 

 Darwinism and neo-Darwinism and then presents a systematic comprehensive theory of 

 evolution which takes much more account of epigenetic phenomena than the former two 

 theories, and relies rather heavily on hypothetical "large mutations". 



The emphasis in this book is on the whole organism and the cell. The molecular 

 approach is viewed critically. The treatment is not very up to date: of many leading 

 developmental biologists one finds only older literature cited. The modern work on insect 

 morphogenesis, which has profound bearings on the issues discussed in the book, is not 

 mentioned at all. Particularly as a work of theoretical biology the book makes a 

 somewhat dated impression. This is not necessarily a fault, for some good "old-fash- 

 ioned" thinking can be very wholesome, if only as an antidote to the fashions of the day. 

 Yet, it is curious to find no mention of leading present-day theoretical biologists such as 

 J. T. Bonner, Goodwin, Cohen, and Kauffman, to name but a few. There is no reference 

 to cybernetics, systems analysis, or model building, although the computer is mentioned 

 as an analogy for epigenesis. The book draws heavily on theorists of one or two 

 generations ago, such as Woodger, Goldschmidt, Schindewolf, and Waddington. This does 

 not alter the fact that it is an unorthodox and thought-provoking opus. 



Monographs 



13. 



P. BRIEN. 1974. LE VIVANT; Epigenese, Evolution epigenetique (Propos d'un zoolo- 



giste) 



Edit, de I'Univ. de Bruxelles, Bruxelles. 155 pp. B.fr. 275 (paper) 



Contents: L'unite de I'etre vivant et I'epigenese; Le polymorphisme intraspecifique et 

 I'epigenese; L'evolution biologique et I'epigenese; Les theories explicatives du fait de 

 revolution biologique; L'evolution epigenetique 



Paul Brien, who died on February 19th, 1975, was one of those allround zoologists 

 who today seem to become rare. He has always gone his own way without allowing 

 himself to be influenced by the fashions of the day. Two strong influences do manifest 

 themselves in this book, however: Lamarck and Driesch (though not the latter's vitalist 

 views). At the end of a prolific life Brien has now given us his summing-up in the form of 

 what is best characterized as "the philosophy of a zoologist". His own contributions to 

 developmental biology (particularly asexual reproduction), on which he draws extensive- 

 ly, are well known. 



Epigenesis is the key concept of the book, both for ontogenesis and evolution. The 

 two are really one, for "la phylogenese [est le] but supreme des etudes zoologiques". 

 Brien considers it futile to contrast "holist" and "atomist" biologists, for every biologist 

 is both at the same time. But to him the primary problem in biology is form and 

 organization, not the "programme" (genetic or otherwise). Biology is a science of 

 observation and experiment (to both of which he has himself made great contributions), 

 but it is above all a "science d'integration". "Information" contained in the germ cell and 

 its DNA is a potentiality whici; must realize itself in the flexible programmes of 

 development. 



Brien defines evolution as typogenesis, the "creative", saltatory remodelling of the 

 entire organization of organisms. It is initiated by change mutations but for its stabiliza- 



196 



I 



