#greatscientists

Claude Bernard was born in a little town called Saint-Julien, on July 12, 1813. He did his elementary studies at the Jesuit school of the parish church and then went on to the Jesuit College in Villefranche-sur-Saone and the Collège Royal de Thoissey.

Claude Bernard became interested in romanticism, both in its art and literature. His idol at that time was also the physicist Fresnel, whose principles of light refraction were being incorporated into the design of headlights, as well as studying color and light theory. He soon dropped out of school and, in 1832, worked as an assistant in a pharmacist's shop. And in his spare hours, he composed a comedy called La Ross du Rhone, and his success with this play led him to compose a five-act drama called Arthur de Bretagne.

The Young Adult

At the age of 21, he went to Paris with a letter of introduction to Saint-Marc Girardin, an art critic, who dissuaded him from becoming a playwright and instead encouraged him to study medicine. Bernard followed the advice and shortly after was an intern at the Hotel de Dieu, which put him in contact with François Magendie, becoming his official tutor at the College de France in 1841. Six years later, he was named Assistant Professor, and in 1855, upon Magendie's death, he succeeded him as Professor.

Shortly before, he had been chosen to occupy the Chair of Physiology at the Sorbonne University, and although he had no laboratory, after an interview with Louis Napoleon in 1864, he assigned him the position of Professor in the Laboratory of the Museum of Natural History, in the Jardin des Plantes. He died in Paris in 1878 and had a public funeral, like the one granted to Heads of State and that France had not previously granted to a scientist. Bernard was buried in the famous Cimetière du Père Lachaise, Paris, France.

The discoverments of Claude Bernard

Bernard began working on the problem of gastric acidity, concluding that the person responsible for the acidity of gastric juice was lactic acid, but he soon corrected this error and assigned that role to hydrochloric acid. He then worked on anatomical dissections and assisted Magendie in his experiments on the phenomenon of the recurrent sensation of the spinal nerve roots, as well as testing the effect of the activity of cranial nerves X and XI on the vocal cords. These works won him the prize for Physiology from the Académie des Sciences.

One day his friend and protector Theóphile-Jules Pelouze showed him some arrowheads soaked in curare that a friend of his had brought from South America, asking him if he could find out exactly how it killed its victims. Bernard used various animals to discover that curare is very selective for the neuromuscular plaque and because it paralyzed the respiratory muscles, victims died of asphyxia while fully conscious. The article on this work, in collaboration with his friend Pelouze, was published a few years later.

For the next 20 years, Bernard continued to work on curare at intervals, showing that its effect was exclusively on the motor nerves. If the animal was maintained with artificial respiration, the effect of the drug ended, and the muscle would contract normally again. This led to the use of curare as a muscle relaxant during tetanus, severe epilepsy, and abdominal surgery.

His most famous research is on the glycogenic function of the liver, which he did in 1855, and during which he concluded that in addition to the external secretion of bile, the organ also produced an internal secretion, the release of sugars into the blood. He described hepatic glycogenesis in dogs fed protein and sugar, isolating glycogen from the liver, and observing hyperglycemia after the puncture of the fourth ventricle.

His third scientific problem resulted in the discovery of the vasomotor system. In 1851 and while examining the effect of temperature on various parts of the body by cutting the nerves that innervated it, he noticed that the distal end of the cervical sympathetic increased the speed of circulation and made the pulse more noticeable in the arteries in some parts of the head; shortly afterward he also noticed that electrical stimulation of the proximal portion of the divided nerve had the opposite effect. In this way, he established the existence of vasomotor, dilator, and constrictor nerves.

The Legacy of Claude Bernard

He favored the study of the physiological activity of poisons, in particular curare and carbon monoxide gas. Although he published his data in scientific journals, he saved his best comments for his public exhibitions, which he gave with great dramatic force, and the series of these lectures filled 17 volumes called 'Cahiers' (Notebooks). He also published two very famous books, Introduction à la medicine expérimentale (1865) and Physiologie genérale (1872).

Claude Bernard modernized the teaching of medicine by introducing the basic sciences in the University curriculum, being considered the founder of the modern science of endocrinology. 

He is currently known, among many other things, for his formulation of the concept of the 'constancy of the internal environment' and that Walter Cannon baptized with the name we now know it by, homeostasis.

Bernard also left his name on a rare congenital disease called Bernard-Horner Syndrome or Oculosympathetic Palsy. Currently, the disease is attributed to a sympathetic-cervical lesion and is both congenital and acquired, being associated with sympathectomies performed to relieve chronic pain. It is characterized by eyelid ptosis (drooping eyelids), miosis (decreased pupil opening), anhydrosis (insufficient sweating), and heterochromia of the iris (differently colored eyes).

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