Evolution of Physiological and Behavioural Mechanisms in Vertebrate Body Fluid Homeostasis

Abstract

Fluid and electrolyte balance is maintained because, as stated by Claude Bernard, constancy of the internal environment is a necessary condition for a free and independent existence (Bernard 1878). L. J. Henderson was instrumental in introducing Bernard’s ideas to the English-speaking world by arranging for Introduction à l’étude de la médecine expérimentale to be translated into English by H. C. Green. Many others, including W. M. Bayliss, E. H. Starling, J. S. Haldane, J. Barcroft and W. B. Cannon, built on Bernard’s ideas in their own work. Cannon introduced the term homeostasis, defined as “... the physiological rather than the physical arrangements for attaining constancy”. He went on to say why use of a special word was justified: “The co-ordinated physiological reactions which maintain most of the steady states of the body are so complex, and are so peculiar to living organisms, that it has been suggested... that a specific designation for these states be employed — homeostasis” (Cannon 1929, p. 400).