Unlikely individuals inspire correspondent
The rabbit lived an uneventful life of no particular consequence until it met the hands of Claude Bernard. Bernard chose the rabbit for its long ears.
Bernard was a rotund man with determined eyes and a passion for the study of physiology. On that morning, wearing his white apron, he wrapped each of the rabbit’s ears separately and attached to each a device for measuring temperature.
He gathered around him a few of his students and several colleagues, and called for his assistant. The vivisection–surgery on a living animal–was performed in Bernard’s dark, damp laboratory. Bernard held a scalpel and cut through the rabbit’s skin. The rabbit whimpered, it tried to escape, but was held still by the assistant.
Bernard then cut through the rabbit’s muscles and connective tissues, reaching for the rabbit’s cervical sympathetic nerve on its left side. He cut the nerve and stimulated the nerve with a needle, on and off, while measuring the temperature in the rabbit’s ears. In that particular rabbit experiment, Bernard proved, without any doubt, that stimulating the sympathetic nerve leads to a change in the blood flow to the rabbit’s ear, and in its temperature.
You might ask, who cares about the temperature in a rabbit’s ears? And what happened to Bernard’s sad rabbit?
As a young man, the energetic, enthusiastic Claude Bernard (1813-1878) was working as an apprentice in a local pharmacy. He was interested in a career in the theater, but when he showed a play he wrote, Arthur de Bretagne, to a renowned critic of the day, the critic shrugged his shoulders and suggested that he try medicine instead. He studied medicine with little enthusiasm, and found his calling working in the laboratory with Francois Magendie, a professor of Medicine at the College de France whose main interest was in physiology. Bernard married Fanny Martin, the daughter of a rich doctor, whom, it seemed, he never loved. Her dowry allowed Bernard to stay in research. Their marriage was long but miserable. Among the many points of contention was Bernard’s tendency to bring his work home: He would bring with him some of the animals he studied, cut open and half-alive, with tubes and other devices still stuck in their bodies; he operated on the family dog; he might have even brought the rabbit home, with its ears wrapped, one ear warmer than the other.
In a separate series of experiments, Bernard discovered glycogen–the substance used to store glucose (sugar) in the liver–and showed that stimulation of the vagus nerve would lead to an increase in the level of sugar in the blood and in the urine.
These and other experiments must have led Bernard to deep thoughts about the complexity with which the body operates. In the rabbit experiment, he could see that a mechanism exists by which the body regulates the blood flow and the temperature of a rabbit’s ears. In the liver experiment, he could see that a mechanism exists by which an organism controls its own level of glucose. Bernard must have concluded that there are more mechanisms to control the environment in which our body functions. Bernard must have surmised that these mechanisms keep our internal environment steady. But against what, he must have asked himself? Against the ever changing external environment, was his answer.
He called this process milieu interieur, (French for internal environment). He wrote: “The stability of the internal environment [the milieu interieur] is the condition for the free and independent life.”
Bernard was recognized for his accomplishment during his lifetime. Napoleon Bonaparte, the emperor of France, built for him a laboratory at the Museum national d’Histoire naturelle. He became a member of the Acadamie francaise and when he died on a cold day in February 1878, he was accorded a public funeral, an honor never before bestowed on a man of science.
In my previous article I told you about Mr. Ralph A., a 65 year-old school-principal in New England who presented to the Emergency Room with progressive fatigue, morning headaches, forgetfulness and confusion. “There is something wrong with my husband,” Ralph’s wife told the doctor. “It seems that he lost his stream of consciousness.” And I told you that despite the different time in which they lived and the geographical distance that separated them, the stories of Ralph and that of Claude Bernard, a 19th century French physiologist, intersect in my mind. But how? Perhaps Claude Bernard’s observations, and his milieu interieur theory is the basis for understanding, and solving Ralph’s medical mystery. I shall return.
Editor’s note: Dr. Shahar Madjar is a urologist working in several locations in the Upper Peninsula. Contact him at email@example.com or at DrMadjar.com