Jean François Fernel (in Latin, Fernelius) (1497 – 26 April 1558) was a French physician who introduced the term "physiology" to describe the study of the body's function. He was the first person to describe the spinal canal. The lunar crater Fernelius is named after him.
Fernel suggested that taste buds are sensitive to fat, an idea which only recently has been shown to be correct.
He was born at Montdidier, and after receiving his early education at his native town and at Claremont, he entered the College of Sainte-Barbe, Paris. At first he devoted himself to mathematical and astronomical studies; but from 1534 he gave himself up entirely to medicine, in which he graduated in 1530. His general erudition, and the skill and success with which he sought to revive the study of the old Greek physicians, gained him a reputation, and ultimately the office of physician to the court. Catherine De' Medici, wife of King Henri II of France, sought his advice regarding their difficulty in conceiving a child. He practised with success, and at his death at Fontainebleau in 1558 left behind him a large fortune.
Fernel's Cosmotheoria (1528) records a determination of a degree of arc of the meridian, which he made by counting the revolutions of his carriage wheels on a journey between Paris and Amiens. His works on mathematical and astronomical subjects also include Monalosphaerium(1526), and De proportionibus (1528).
His medical works included De naturali parte medicinae (1542), De vacuandi ratione (1545), De abditis rerum causis (1548) which included a chapter on angelology and demonology. What has been called his "crowning work", Universa Medicina, comprising three parts, the Physiologia (developed from the De naturali parte), the Pathologia, and the Therapeutice.
Further reading 
Granit, Ragnar (1970–80). "Fernel, Jean François". Dictionary of Scientific Biography 4. New York: Charles Scribner's Sons. pp. 584–6. ISBN 0684101149.
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