From bench to bedside: Claude Bernard, Henry K. Beecher, MD, and science in anesthesia.

Success with the medical management of pain grew tremendously after William Thomas Green Morton's successful demonstration of surgical anesthesia in 1846: Henry K. Beecher's clinical and experimental contributions to anesthesia during and after World War II had a profound impact on how clinicians and experimentalists study human populations in medicine. Beecher found that pain research required human subjects because pain was different for each individual. Nearly 100 years before Beecher, Claude Bernard similarly considered the complexity and uniqueness of human research subjects. Bernard and Beecher both preferred animal subjects in research when appropriate, but suggested that studies involving some mental, bodily, and cognitive processes required human subjects. Although Beecher and Bernard's lives did not overlap, these two men similarly confronted the issues of complexity in human and animal research, particularly in those phenomena involving higher cognitive functions.