The Expression of the Emotions in Man and Animals Robert Grant's Lamarckist philosophy) ridiculed Bell's theological explanations, pointing instead to the striking similarities of human and animal biology. The meeting then ended in uproar. Forty-five years later, Darwin revisits these arguments and recruits Duchenne's (1862) unmasking of the facial mechanisms, shifting the argument from philosophical speculation to scientific discourse. Darwin's response to Bell's natural theology is discussed by Lucy Hartley (2001). In the composition of the book, Darwin drew on worldwide responses to his questionnaire (circulated in the early months of 1867) concerning emotional expression in different ethnic groups; on anthropological memories from his time on ; on conversations
The Expression of the Emotions in Man and Animals shows how human emotions link mental states with bodily movement, and are genetically determined, deriving from purposeful animal actions. He comments on the implications of the book: a single origin for the entire human species, with universal human expressions; and he stresses the social value of expression, citing the emotional communication between mother and child. This was one of the first books to be illustrated with photographs – with seven heliotype plates – and the publisher John Murray warned that this "would poke a [terrible] hole in the profits". The published book assembled illustrations rather like a Victorian family album,