I have now (May 1, 1881) sent to the printers the MS. of a little book on 'The Formation of Vegetable Mould, through the Action of Worms.'

The Formation of Vegetable Mould through the Action of Worms, with Observations on their Habits (sometimes shortened to Worms) is an 1881 book by Charles Darwin on earthworms.

There were only two more books to follow: The Power of Movement in Plants (1880) and The Formation of Vegetable Mould through the Action of Worms (1881).

Before Easter he sent off his manuscript for The Formation of Vegetable Mould through the Action of Worms, and found he had no "heart or strength... to begin any investigation lasting for years".

October - Charles Darwin publishes his last scientific book The Formation of Vegetable Mould through the Action of Worms.

See "The Formation of Vegetable Mould," 1881, pages 178 et seq.

F. Muller's reply is given in "Vegetable Mould," page 122.

"The Formation of Vegetable Mould through the Action of Worms," 1881, page 71.

In his last book he returned to The Formation of Vegetable Mould through the Action of Worms.

Charles Darwin's book The Formation of Vegetable Mould through the Action of Worms (1881) presented the first scientific analysis of earthworms' contributions to soil fertility.