This volume contains contributions that are interdisciplinary and inter national. The editors believe this is an especially timely and promising enterprise, for both sources of diversity are needed for improving our abilities to identify the young child at risk and to prevent disability. In terms of diSciplines, the volume brings together papers by health care providers (such as pediatricians and public health nurses) as well as educators and psychologists. Each of these groups works in dissimilar settings and faces dissimilar problems: Health care providers seek sim ple identification...

There can be few elements with a biochemistry as coherent as that of sulfur. This important element is crucial to myriad aspects of metabo- lism, catalysis, and structure. The plurality of functions in which sulfur is involved derives squarely from the numerous oxidation states in which it may exist, some having great stability, some being capable of ready redox interconversions, and yet others having great instability. As a result, the flux of sulfur from the geosphere through the various kingdoms of life leaves few biochemical processes unaffected. Although there are large gaps in the...

Any branch of biology depends for its progress on the development of new concepts and to a lesser, but sometimes crucial, extent on the elimination of erroneous notions. Understanding the roles of bacteria required first the observation that such minute creatures existed, and subsequently the exper- imental demonstrations that their presence was necessary for the occurrence of particular phenomena. In this first volume, the authors review the development of scientific understanding of the role of microbes as agents of diverse natural processes. Notably absent is a separate review of the...

The value of studies of monotypic populations is constantly argued in bacterial ecology. The controversy itself is evidenceofthe strong awareness that bacterial activities in natural sites are not determined by the bacteria alone. At the same time, the best evidence that bacteria are influenced by environmental factors is the contrast between their behavior in laboratory cultures and their relatively subdued influence when in the presence of com petitors, predators, and fluctuating-often stressful-environmental conditions. Monotypic populations are admittedly reductionist, but are not...