Mead proves that the plague is contagious from Thucydides, Lacretius, Aristotle, Galen, and common experience (p. 10 - 20) ; and he refutes (Preface, p. 2 - 13) the contrary opinion of the French physicians who visited Marseilles in the year 1720. Yet these were the recent and enlightened spectators of a plague which, in a few months, swept away 50,000 inhabitants (sur le Peste de Marseille, Paris, 1786) of a city that, in the present hour of prosperity and trade contains no more then 90,000 souls (Necker, sur les Finances, tom. i. p. 231.).