The basic principles of scientific research from the great French physiologist whose contributions in the 19th century included the discovery of vasomotor nerves; nature of curare and other poisons in human body; more.

Introduction.--Aristotle.--The seventeenth century.--The eighteenth century.--Biology.--Nature.--Evolution.--The problem.--The three elements.--The teleological order.--Appendix: Clerk Maxwell on determinism and free will. Fechner on the tendency to stability.