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a b o u t Sulfolobus, he relates the events that led to its isolation and its eventual naming. Then, as a note to the chapter, he tells us a b o u t his difficulties obtaining peer approval of a final manuscript. Finally, he concludes the b o o k with a discussion a b o u t the initiation and termination of the project. Through this approach, he clearly shows us the very human side of science, a side which is often absent from modern science writing. In reviewing this book, I have found it difficult to remain objective. Tom Brock was first m y teacher, then m y colleague and now m y friend. Having thus warned the reader of this review to be aware of m y biases, I do recommend this book. For the person interested in studying the organisms, Carr and Whiton's The Biology of Blue-Green Algae (University of California Press), or Kushner's Microbial Life in Extreme Environments (Academic Press), may provide more extensive information (Brock did contribute to both of these works) However, for the person interested in understanding the interactions of microorganisms and their environment, this b o o k is more thought provoking and provides more tools to develop a meaningful study. I also think that the b o o k serves as an example o f the benefits of interdisciplinary research. Had Brock simply isolated organisms from the environment and returned to the microbiology laboratory, he would have missed much of their significance. By remaining in the environment, he had to confront the relevance of geology and chemistry to microorganisms. In turn, I think that he may have contributed to the geologists' understanding of the relevance of microorganisms. W.N. DOEMEL (Crawfordsville, Ind.)
Formation and Properties of Clay--Polymer Complexes. B.K.G. Theng. Developments in Soil Sciences, 9. Elsevier Scientific Publishing Company, Amsterdam--Oxford--New York, N.Y., 1979, 362 pp., Dfl. 122.00/ US $ 64.50. This review of clay--polymer interactions should enjoy a success equal to that of the author's earlier review of the reactions of clays with smaller organic molecules. From what is often a confusing and complex literature, Dr. Theng has made a bold a t t e m p t to draw general principles and unifying concepts, without glossing over apparently conflicting and contradictory results. Although many of these rationalizations will inevitably prove to be over-simplified or mistaken, this b o o k will remain for some time the best entry to this field, and its literature up to the end of 1976, for research workers, applied scientists, and teachers and students at graduate and postgraduate levels. It will also provide a stimulus to research workers to resolve some of the apparent contradictions and to provide a better understanding of the complex processes involved. The b o o k is in three parts: The first gives a brief review of clay structures and colloidal properties, and a summary of the concepts of p o l y m e r science
359 that are relevant to polymer sorption processes. The second reviews the interaction of clays with synthetic polymers, with separate chapters on nonionic polymers, polyanions, polycations, and practical applications of clay-polymer interactions. The third section covers interactions with natural polymers -- proteins, enzymes, nucleic acids, nucleoproteins, viruses, polysaccharides, lignosulphonates and humic substances. The presentation is clear and logically organized, and there is every evidence of a careful critical study of a large and often conflicting literature. A summary at the end of each chapter, however, would have assisted the reader to obtain an overall view of the principal conclusions reached. The b o o k is well produced and almost free from misprints, but the chapter on clay structures exhibits some misconceptions which may mislead the beginner or non-expert. In c o m m o n with many other texts, it presents an erroneous structure for the 2:1 dioctahedral layer silicates, such as muscovite, showing the centro-symmetric octahedral site occupied instead of vacant. The terms dimorphic and trimorphic are used instead of diphormic and triphormic for 1:1 and 2:1 layer silicates. It is wrong to assert that macroscopic forms of vermiculites, micas, and chlorites do not occur in soils. The author, like t o o many others, hybridizes the expressions "replace b y " and "substitute for" to produce the confusing usage, "replacement of A1 for Mg". These faults are mentioned in the hope that their further proliferation may be checked: they are of minor importance for the main subject of this book. v.c. FARMER (Aberdeen)
Geochemistry of Colloid Systems for Earth Scientists. Samuel Yariv and Harold Cross. Springer-Verlag, Berlin--Heidelberg--New York, N.Y., 1979, DM l l 0 . 0 0 / U . S . $ 60.50. This b o o k is an a t t e m p t to summarize the progress made these last twenty years on colloids and to examine what colloid science has contributed and can further contribute to geochemistry. It is divided into ten chapters treating various subjects: Some geologic colloid systems such as soils, sediments, oceans, atmospheres, lavas and magmas (Chapter 1); Physical chemistry of surfaces with sorption, liquid surface, thermodynamic and electrochemistry of heterogeneous systems (Chapter 2); Formation of aqueous solutions and suspensions of hydrophobic colloids with different considerations on chemistry of aluminium, iron and manganese in natural waters and weathering processes (Chapter 3); Surface coatings on rocks and grains of minerals in which incongruent dissolutions, sorption into mineral surfaces and alteration of minerals are treated (Chapter 4); Kinetic properties of colloid solutions including properties of particles in still or flowing fluids (Chapter 5); Colloid geochemistry of silica: functional groups, polymerization, sorption and solubility (Chapter 6); Colloid geochemistry of