Scientists from Brittany

Alphonse François Marie Guérin (French pronunciation: [alfɔ̃s fʁɑ̃swa maʁi ɡeʁɛ̃]; August 9, 1816 – February 21, 1895) was a French surgeon who was a native of Ploërmel.
He studied medicine in Paris, and in 1850 became a surgeon of Parisian hospitals. During his career, he practiced surgery at the Lourcine, Cochin, Hôpital Saint-Louis and Hôtel-Dieu. In 1868 he became a member of the French Académie Nationale de Médecine.
In 1870, Guérin introduced the practice of using cotton-wool bandages for prevention of wound infections. He described a horizontal fracture of the maxilla immediately above the teeth and palate, that is known today as a "Le Fort I fracture", or sometimes as a "Guérin fracture".

Angelo Louis Marie Hesnard (or Angel Marie Louis Hesnard; 22 May 1886, Pontivy – 17 April 1969, Rochefort) was a French born psychiatrist and psychoanalyst, and was an important figure in 1930s French sexology.

Jean Jouzel (born 5 March 1947) is a French glaciologist and climatologist. He has mainly worked on the reconstruction of past climate derived from the study of the Antarctic and Greenland ice.