How did Claude Bernard’s health affect his later scientific work?

After 1860, Claude Bernard’s declining health—specifically chronic enteritis with symptoms affecting the pancreas and liver—significantly altered the trajectory of his career.1

As his physical condition forced him to spend less time in the laboratory and more time at his home in Saint-Julien, he shifted his focus from active experimentation to the philosophy of science. This period of enforced leisure provided him the opportunity for reflection, which resulted in his masterpiece, An Introduction to the Study of Experimental Medicine. In this seminal work, Bernard argued that medicine must be grounded in experimental physiology and established foundational concepts regarding the internal environment of the body.1