The Expression of the Emotions in Man and Animals allows cultural factors only an auxiliary role in the shaping of expression. This biological emphasis leads to an appreciation of the universal nature of expression, with its implication of a single origin for the entire human species; and Darwin points to the significance of emotional communication with children in their psychological development. Darwin sought out the opinions of some leading British psychiatrists, notably James Crichton-Browne, in the preparation of the book which forms his main contribution to psychology. Amongst the innovations with this book are Darwin's circulation of a questionnaire (probably inspired by his cousin, Francis Galton) in his preparatory
The Formation of Vegetable Mould through the Action of Worms went the less controversial direction of the lowly worm. His network of correspondents and fans responded to his interest and "earthworm anecdotes began surfacing in his mountain of mail". He had been interested in earthworms "since his first fishing days at The Mount and flirting days at Maer". Still, other work constrained him. Broken off from "Descent", he had to finish his next work "The Expression of the Emotions in Man and Animals". By 1876, with his first grandson on the way, he felt his writing life was nearly over, with so much unfinished. He wanted to write on earthworms