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 with livestock breeders and pigeon fanciers; on observations on his infant son William Erasmus Darwin ("A Biographical Sketch of an Infant" - published as a paper in the philosophical journal "Mind"), on his family's dogs and cats, and on the orangutans at London Zoo; on simple psychology experiments with members of his family concerning the recognition of emotional expression; on the neurological insights of Duchenne de Boulogne, a physician at the Salpêtrière asylum in Paris; on hundreds of photographs of actors, babies and children; and on descriptions of psychiatric patients in the West Riding Pauper Lunatic Asylum at Wakefield in