Studies will be made of the energy requirements of the various processes occurring in peripheral nerves of fish, amphibia and mammals. The metabolic rate in nerves at rest, with and without blockage of such functions as the cation pumps and axoplasmic flow, will be measured by observing changes in high energy phosphates and glycolytic reserves in isolated, anoxic nerve. By measuring the redistribution of enzymes in isolated segments of peripheral nerve in vitro, movement of organelles by axonal transport will be studied. Inhibitors of transport, e.g. vinblastine, will be examined for differential effects upon the transport of the various organelles. By assessing the effects of various drugs and poisons upon the function and metabolism of nerve, efforts will be made to differentiate between the contributions made by the axon and those made by the Schwann cell.