The Expression of the Emotions in Man and Animals Darwin notes the universal nature of expressions in the book, writing: "the young and the old of widely different races, both with man and animals, express the same state of mind by the same movements." This connection of mental states to the neurological organization of movement (as the words "motive" and "emotion" suggest) is central to Darwin's understanding of emotion. Darwin himself displayed many biographical links between his psychological life and locomotion, taking long, solitary walks around Shrewsbury after his mother's death in 1817, in his seashore rambles near Edinburgh with the Lamarckian evolutionist Robert Edmond Grant in 1826/1827, and
Darwin from Descent of Man to Emotions our work; and of these you rank as the first." With "the little strength left in me" he reopened his enquiries into earthworms, requesting information from correspondents. The 6th edition of "Origin of Species" was published by Murray on 19 February 1872 at a price kept down to 7s. 6d. by using minute print, and sales increased from 60 to 250 a month. Through the spring Darwin pressed on with "The Expression of the Emotions in Man and Animals", pointing to shared evolution in contrast to Charles Bell's "Anatomy and Physiology of Expression" which claimed divinely created muscles to express