This volume brings together two previously unpublished works by the late George Scatchard. One of the most eminent physical chemists of this century, Scatchard, in collaboration with Edwin Cohn, had enormous influence on the development of protein chemistry. The “Scatchard Plot,” a device for evaluating the interaction of proteins with smaller molecules, is today a ubiquitous feature of articles on biochemistry, immunology, and endocrinology.

These two monographs concern the laws of thermodynamics and the Oebye-Huckel theory as they are applied to the physical chemistry of inorganic and organic systems in solution. A unique feature of both works is their detailed extension of thermodynamic principles to the interactions of dissolved proteins with each other and with small molecules. They represent one of the most important links between the classical physical chemistry of the first four decades of this century and the contemporary science of protein chemistry.

Known previously only to a limited audience of Scatchard's students and colleagues, these remarkable treatises deserve much wider circulation today. Succinct, comprehensive, and systematic, they will stand as useful guides to one of the central sciences of our time.

Natural microbial habitats include various interfaces--liquid-liquid, gas-liquid, solid-liquid, and solid-gas. An interface, the boundary between two phases, has physical and chemical properties that differ from those of either phase. Bacteria, yeasts, and algae often concentrate at interfaces, and the ability of microorganisms to exploit resources in their environment may be markedly affected by the nature of the available interfaces. Included within the realm of microbial activity at interfaces are such wide-ranging topics as predator-prey relations, tooth decay, gastrointestinal tract infections, mating contact, marine fouling, adsorptive bubble processes, oil degradation, rhizosphere associations, and bacterium-clay interactions.

In this book, bacteria are treated as living colloidal systems, and the behavior of microorganisms at interfaces is analyzed on the basis of this concept. Nonspecific physical and chemical forces acting on microorganisms at interfaces are described and related to biological factors determining the distribution of and interaction between microorganisms in both aquatic and terrestrial ecosystems. The final chapter describes specific microbe-microbe, microbe-plant, and microbe-animal interfacial interactions.

Although laboratory studies of cultured microorganisms are essential in assessing their potential capabilities, an individual microbial species in a natural habitat is confronted by physical, chemical, and biological interactions rarely encountered under pure culture conditions. Interfaces are important aspects of microbial ecosystems, and this study of the influence of interfaces on natural habitats is an important and original contribution to microbial ecology.