Psychoneuroimmunology
Claude Bernard, a French physiologist, founded the concept milieu interieur in the mid-1800s. In 1865, Bernard described the perturbation of this internal state “… there are protective functions of organic elements holding living materials in reserve and maintaining without interruption humidity, heat and other conditions indispensable to vital activity. Sickness and death are only a dislocation or perturbation of that mechanism." (Bernard, 1865)