Octavo (19 cm); vi, 374 pages including 21 text illustrations, and seven photogravure plates, three of them folding, . Lacks half title and ads. In custom prize binding for the London School of Dental Surgery, polished red calf ruled in gilt, with gilt emblem of the school on upper board, gilt-tooled spine in six compartments with green leather title label; marbled edges and endleaves, by Bickers and Son. Ownership autograph and ink stamp of Henry B. Mason (1855-1923). About fine. Seen by some as the origin of modern understandings of emotion, and incidentally the first English Language science book to be illustrated with photographs.