The Formation of Vegetable Mould, Through the Action of Worms, with Observations on Their Habits was published by John Murray in October 1881, six months before Darwin’s death. It sold 6,000 copies in the first year — more than The Origin of Species had sold in its first year — and it represents Darwin at his most characteristic: a seemingly trivial subject investigated with such thoroughness and insight that it reveals fundamental principles of natural history.
Darwin had been studying earthworms for over forty years, beginning with a paper read to the Geological Society in 1837. His central argument is that earthworms, through their ceaseless activity of ingesting soil and casting it on the surface, are one of the most important geological agents in the world. They turn over enormous quantities of earth — Darwin calculated that worms in an English field produce ten tons of castings per acre per year — and in doing so they bury stones, ruins, and artifacts, level surfaces, and create the fine, fertile topsoil on which agriculture depends.
The book includes experiments of remarkable ingenuity. Darwin tested worms’ senses by playing piano and bassoon to them (they were deaf to airborne sound but responded to vibrations through the ground). He offered them different shapes of paper to determine whether they used intelligence or instinct in pulling leaves into their burrows (he concluded they showed a degree of intelligence). He measured the rate at which objects sank into worm-worked soil, using everything from Roman ruins to his own lawn.
First edition (John Murray, London, 1881): Green cloth binding.
Market values:
- First edition, fine: $1,000–$3,000
- Very good: $400–$1,000
- Good: $150–$400