Parikian revisits Down House, Darwin's earthworm lab — SkimNews
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- Lev Parikian visited Down House, where Darwin lived and wrote his final book, "Earthworms," reflecting on the naturalist's decades of meticulous research into the creatures.
- Darwin tested worms for intelligence, sensitivity to atmospheric variations, and senses of taste, smell, and hearing — the hearing test involved his son Frank playing the bassoon to them.
- A wormstone — a wood-and-copper apparatus at Down House — measured soil displacement at approximately 2mm annually, per a circular stone slab still embedded in the grounds.
- A modern estimate cited in the piece suggests earthworms turn over the equivalent of all the world's soil to a depth of one inch every 10 years.
- Darwin concluded that few animals "have played so important a part in the history of the world" than earthworms, whom Parikian calls "custodians of the soil."
Why it matters: Darwin's last book, often overshadowed by his evolutionary work, reframed earthworms as ecosystem engineers whose collective labor sustains soil fertility and carbon cycling — his 2mm-per-year displacement finding has been validated by modern estimates that worms turn over all earth's topsoil to a depth of one inch each decade, underscoring an enduring ecological legacy too easily missed in standard Darwin retellings.
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