law"—i.e., a law of elastic fluids, according to which the elastic force is exactly in the inverse proportion of the space which the mass of fluid occupies. He also discovered that the part of the retina at which it meets the optic nerve is not capable of conveying the impression of sight. Finally, Denis Papin (1647-1710), a Frenchman, invented the first steam engine, of an embryonic and not very practical type; for in this apparatus the piston floated on the water in a separate cylinder.
The inventions which I have here briefly enumerated represent the more important discoveries that were made in physical science during the sixteenth and seventeenth centuries.
The Beginnings of a Modern Pharmacopoeia, and One of the Last Attempts of the Disciples of Galen to Maintain Their Ascendancy in Therapeutics.—In the domain of pharmacology the first attempt in modern times to organize this department of practical medicine was made by an apothecary in Barcelona in 1497, and was published by him in printed form in 1521. (Von Gurlt.) This pharmacopoeia was doubtless wholly unknown beyond the borders of Spain. Not far from one hundred years later,—i.e., in the early part of the seventeenth century,—Theodore Turquet de Mayerne, who was born in 1573, in a small village near the city of Geneva, made the second attempt in modern times to organize the pharmacological department of practical medicine. After showing quite early in life a fondness for the study of chemistry, he devoted himself particularly to the investigation of the remedies that are produced in the chemist's laboratory; the preparations of antimony attracting his especial interest. A little before this time the physicians of Paris were split up into two strongly antagonistic parties as regards the propriety of administering this metal in any form as a remedy; but those who opposed its therapeutic employment finally managed to secure from Parliament, in 1566, a decree prohibiting its use. While this quarrel was in progress, de Mayerne visited Paris (1602) and established himself in that city as an independent lecturer on chemistry. As
