The Expression of the Emotions in Man and Animals in the laying out of the sandwalk, his "thinking path", at Down House in Kent in 1846. These aspects of Darwin's personal life are discussed in John Bowlby's (1990) psychoanalytic biography of Darwin. Darwin emphasises a shared human and animal ancestry in sharp contrast to the arguments deployed in Charles Bell's "Anatomy and Philosophy of Expression" (1824). Bell claimed that the facial muscles were divinely designed in order to express uniquely human feelings. Eager to stress the differences between human and animal communication, Bell wrote: "Expression is to the passions as language is to thought." In "The Expression", Darwin reformulates
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