PHYSIOLOGIC HOMEOSTASIS

Half a century ago the French physiologist Claude Bernard wrote that all the vital mechanisms, however varied they may be, have only one object, that of preserving constant the conditions of life in the internal environment. By the latter was meant that entity which has been described as the fluid matrix of the body. In spite of a continued succession of influences that tend to bring about changes in the fluids and tissues—for example, hot or cold environments that tend to heat or chill the organism, or stimuli that provoke vigorous action and bring about oxygen want—the tendency to readjustment so that characteristic equilibriums or "steady states" will be restored is always in evidence. For this general idea of uniformity or stability in the organism, Cannon¹ of Harvard University Medical School has proposed the designation "homeostasis."

Physiologic homeostasis is already known to involve many biologic features. They include body