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The Evolution of Differentiation
546
BOOK REVIEWS
normal morphogenesis of the avian embryo and in the involution of the anuran tail. The role of the embryologist in teratology is frequently glossed over, but in her article on the production of twinning and monsters in the chick embryo, R. Bellairs underlines the importance of a detailed knowledge of tissue interactions and cytological changes in assessing abnormal development. Her interesting contribution is ably supported by another equally readable paper on the organotropic effects of some teratogens, in which T. von Kreybig describes how one teratogen can influence the development of two very different organs if it is administered at two different periods of development. In the final section of this book, some problems of teratogenesis in man are outlined, with reference to genetic aberrations and viruses. Several typical cases are described and discussed in detail and among these, G. T6ndury's contribution on the pathogenetic effect of rubella virus on the circulatory system is particularly well presented. Like other contributors, Dr. T6ndury throws light on the limitations and difficulties encountered in the investigation of human deformities. This publication will be valuable both as a standard reference book and as a guide for laboratory investigation. The many difficulties and common pitfalls in teratology are exposed and discussed. However, the overall value of the book would perhaps have been enhanced if some of the early chapters had been abbreviated and the numerous references to thalidomide, which are generally all too well known, had been reduced. The Evolution of Differentiation. By W. S. Bullough. Academic Press, London, 1967. pp. vi q- 206. 45s. The process of cellular differentiation is one of the central problems in biology. It is also one of the central problems in medicine, since its collapse leads to teratogenesis in embryonic life and to cancer in post-natal life. The author considers the differentiation process and its disruption from the point of view of gene expression. Factors controlling gene expression are of obvious importance but the data on these factors are very scanty and too fragmentary to fit together into a simplified theory. The author has nevertheless made an attempt to produce a unified, if not simple, theory that takes into account most of the relevant data. In chapters 5 and 6 he elaborates his hypothesis on intracellular control mechanisms. Among these mechanisms that of gene repression through the agency of the chalone emerges as one of great importance. Of the extracellular factors, the hormones of the adrenal tissue appear to exert a major influence. Unfortunately, however, inadequate attention is given in these chapters to a third factor that regulates cell growth, namely surface contact with the other cells. The text is written in fluent and readable English, and should hold the attention and interest of the reader. This is a great asset in a work of such complexity. Moreover, this book, the result of many years of patient reading, discussion and thinking, may be regarded as one of the few works that have contributed to a real advance in the philosophy behind the biological processes now being subjected to intensive study. Mierosomes and Drug Oxidations. Symposium on Microsomes and Drug Oxidations held at Bethesda, Maryland, February 16-17, 1968. Edited by J. R. Gillette, A. H. Conney, G. J. Cosmides, K. W. Estabrook, J. R. Fouts and G. J. Mannering. Academic Press, New York, 1969. pp. xiv + 547. $12. The essential role played by enzymes of the endoplasmic reticulum of the liver in meta-
BOOK REVIEWS
normal morphogenesis of the avian embryo and in the involution of the anuran tail. The role of the embryologist in teratology is frequently glossed over, but in her article on the production of twinning and monsters in the chick embryo, R. Bellairs underlines the importance of a detailed knowledge of tissue interactions and cytological changes in assessing abnormal development. Her interesting contribution is ably supported by another equally readable paper on the organotropic effects of some teratogens, in which T. von Kreybig describes how one teratogen can influence the development of two very different organs if it is administered at two different periods of development. In the final section of this book, some problems of teratogenesis in man are outlined, with reference to genetic aberrations and viruses. Several typical cases are described and discussed in detail and among these, G. T6ndury's contribution on the pathogenetic effect of rubella virus on the circulatory system is particularly well presented. Like other contributors, Dr. T6ndury throws light on the limitations and difficulties encountered in the investigation of human deformities. This publication will be valuable both as a standard reference book and as a guide for laboratory investigation. The many difficulties and common pitfalls in teratology are exposed and discussed. However, the overall value of the book would perhaps have been enhanced if some of the early chapters had been abbreviated and the numerous references to thalidomide, which are generally all too well known, had been reduced. The Evolution of Differentiation. By W. S. Bullough. Academic Press, London, 1967. pp. vi q- 206. 45s. The process of cellular differentiation is one of the central problems in biology. It is also one of the central problems in medicine, since its collapse leads to teratogenesis in embryonic life and to cancer in post-natal life. The author considers the differentiation process and its disruption from the point of view of gene expression. Factors controlling gene expression are of obvious importance but the data on these factors are very scanty and too fragmentary to fit together into a simplified theory. The author has nevertheless made an attempt to produce a unified, if not simple, theory that takes into account most of the relevant data. In chapters 5 and 6 he elaborates his hypothesis on intracellular control mechanisms. Among these mechanisms that of gene repression through the agency of the chalone emerges as one of great importance. Of the extracellular factors, the hormones of the adrenal tissue appear to exert a major influence. Unfortunately, however, inadequate attention is given in these chapters to a third factor that regulates cell growth, namely surface contact with the other cells. The text is written in fluent and readable English, and should hold the attention and interest of the reader. This is a great asset in a work of such complexity. Moreover, this book, the result of many years of patient reading, discussion and thinking, may be regarded as one of the few works that have contributed to a real advance in the philosophy behind the biological processes now being subjected to intensive study. Mierosomes and Drug Oxidations. Symposium on Microsomes and Drug Oxidations held at Bethesda, Maryland, February 16-17, 1968. Edited by J. R. Gillette, A. H. Conney, G. J. Cosmides, K. W. Estabrook, J. R. Fouts and G. J. Mannering. Academic Press, New York, 1969. pp. xiv + 547. $12. The essential role played by enzymes of the endoplasmic reticulum of the liver in meta-