Paul Bert was a French physiologist whose research laid the foundation for understanding how the body reacts to significant changes in air pressure. This work has proved useful both to undersea explorers and divers and those involved in space exploration.

Born in Auxerre, France, Bert originally entered the École Polytechnique in Paris intending to become an engineer. Changing his mind, he first studied law, then became a student of the Claude Bernard, one of the greatest physiologists of the nineteenth century, and the founder of experimental medicine.

Appointed as a professor of physiology, first at Bordeaux in 1866, then at the Sorbonne (1869-86), he studied the effects of altitude on animals. He discovered that altitude sickness in these animals was caused mainly by a lack of oxygen in the air at high altitudes. In addition, he studied hot air ballonists and discovered that the effects of various respiratory...