From Today in Science History:
Nicolaus Steno. Born 10 Jan 1638; died 26 Nov 1686.
(a.k.a. Niels Steensen, or Stensen) was a Danish geologist and anatomist who first made unprecedented discoveries in anatomy, then established some of the most important principles of modern geology. During medical studies in Amsterdam he discovered “Stensen’s duct” providing saliva from the parotid gland to the mouth. He was Danish royal anatomist for 2 years. Interested by the characteristics and origins of minerals, rocks, and fossils, he published in Prodromus (1669) the law of superposition (if a series of sedimentary rocks has not been overturned, upper layers are younger and lower layers are older) and the law of original horizontality (although strata may be found dipping steeply, they were initially deposited nearly horizontal.)
(1660) On instigation of Thomas Bartholin Steno first travelled to Rostock, then to Amsterdam and studied anatomy under Gerard Blasius, focusing again on the Lymphatic system. Steno discovered a previously undescribed structure, the “ductus stenonianus” (the duct of the parotid salivary gland) in sheep, dog and rabbit heads. A dispute with Blasius over credit for the discovery arose, but Steno’s name is associated with this structure.Within a few months Steno moved to Leiden. There Steno met the students Jan Swammerdam, Frederik Ruysch, Reinier de Graaf, Franciscus de le Boe Sylvius, a famous professor, and Baruch Spinoza. Also Descartes was publishing on the working of the brain, and Steno did not think his explanation of the origin of tears was correct. Steno studied the heart, and found out it was an ordinary muscle.
In 1667, Nicolaus Steno, a Lutheran, converted to Catholicism and became a major figure in the Counter-Reformation.
He was beatified in 1988.
His Major Works:
- Anatomical Observations (1662)
- Concerning Solids naturally contained within solids (1669)
- Elementary Mylogical Specimens (1669)
- Discours de Monsieur Stenon sur L’Anatomie du Cerveau (“M. Steno’s lecture on the anatomy of the brain”, Paris 1669)
(N.B. Some list his birthday as the 1 January, and others as the 11 January)