When describing homeostasis two names are mentioned. These are Claude Bernard (1813-1878) and Walter Cannon (1871-1945). It is Cannon to whom we own the notion of homeostasis. This he popularised in his book The Wisdom of the Body (1932), although he had discussed the idea in academic articles in the previous decade. Bernard spoke of the body’s milieu intérieur (or internal environment) in An Introduction to the Study of Experimental Medicine (1865). He spoke of the constancy of the milieu intérieur but not, of course, homeostasis.
When introducing homeostasis, textbooks often conflate the work of Bernard and Cannon. The impression given is often false. Sometimes, it is as if Cannon built upon the work of Bernard. This is not so. It is uncertain whether Cannon knew of Bernard’s work or the idea of a milieu intérieur. This continues to be a matter of debate for historians of medicine.
Each had important things to say but what they said was different.
