The Expression of the Emotions in Man and Animals public by arguing that humans had "animal traits", and instead charmed them by telling stories of "human traits in animals", thus avoiding too much explicit talk of natural selection at work. Darwin preferred to leave the evolutionary implications hanging. Korn points out that the book has never been out of print since 1872, calling into question Ekman's talk of "Darwin's lost masterpiece". The "Editor's notes" at the "Mead Project source page" on the book comment that Darwin concluded work on the book with a sense of relief. The proofs, tackled by his daughter Henrietta ("Ettie") and son Leo, required a
The Expression of the Emotions in Man and Animals the actor Henry Siddons in his "Practical Illustrations of Rhetorical Gesture and Action" (1807) and by the anatomist Robert Knox in his "Manual of Artistic Anatomy" (1852) – but abandoned them as unreliable, although the text of "The Expression" is littered with quotations from Shakespeare. Darwin opens the book with three chapters on "the general principles of expression", introducing the rather Lamarckist phrase "serviceable associated habits". With this phrase, Darwin seeks to describe the initially voluntary actions which come together to constitute the complex expressions of emotion. He then invokes a principle of "antithesis", through which opposite states of mind