Homeostasis: a history of biology.

Homeostasis is a function indispensable for Life that is accomplished through chemical and physical processes. The mechanisms of this function have been disclosed beginning from the 1920s, when Walther Cannon formulated clear rules that transformed an old concept into paradigm. The concept of harmonic equilibrium among bodily humors dates back to the pre-Hellenic thinkers and was converted into medical suggestions by the Hippocratic school. This concept was handed down to posterity by the several schools of Medicine before being resumed by the great naturalist Jean-Baptiste Lamarck in purely physical terms. The experimental Physiology of the second half of the nineteenth-century elaborated a new conception, the so-called milieu intérieur theorised by Claude Bernard. Toward the half of the 20th century, biochemists imposed the functional basis of the concept, whose mechanisms were definitely established as "feedback" and "allostery".