160. 4-5. Au troisième: French, literally, "on the third," but the meaning is the fourth floor, because the count is begun above the ground floor; Faubourg St. Germain: an aristocratic section of Paris.
160. 15-16. Monsieur G——: introduced in "The Murders in the Rue Morgue."
164. 3. Hotel: in French usage, a dwelling of some pretension,—a mansion.
164. 7. au fait: French for familiar, expert.
168. 26. John Abernethy (1764-1831), an eminent English surgeon, was noted for his brusque manners and his eccentricities.
171. 15-16. François, Due de la Rochefoucauld (1613-1680) was a French moralist, author of the famous "Maxims"; Jean de la Bruyère (1645-1696) was a French essayist; see notes on Machiavelli and Campanella under "The Fall of the House of Usher," page 194.
172. 19. recherché: French for "sought after," selected with care.
173. 1. non distributio medii: "undistributed middle," a term in logic for a form of fallacious reasoning. Consult an encyclopedia, articles on "Logic," "Syllogism," and "Fallacy," or the Century Dictionary under "Fallacy."
173. 16. Nicholas Chamfort (1741-1794), a Frenchman, was said to be the best conversationalist of his day, and wrote famous maxims and epigrams. The quotation means, "It is safe to wager that every popular idea, every received convention, is a piece of foolishness, because it has suited the majority."
173. 27-28. ambitus: a going round, illegal striving for office; religio: scrupulousness, conscientiousness; homines honesti: men of distinction.