Originally posted at ouhos.org, the now-discontinued blog of the OU History of Science Collections. Neither this post nor any of its content should be taken as an official communication of the University of Oklahoma.
The last work Darwin published is one of his least-known, but his study of mold and earthworms drew upon his broad interests. Far from being small and insignificant creatures, Darwin argued, earthworms turn over the soil in vast quantities, creating a suitable habitat for the growth of plants. Drawing upon some of his early geological work in the production of soils, this work represents a founding exemplar of quantitative ecology.
Like Darwin’s other books, it also contains interesting visual representations — for example, a tower of earthworm casts and diagrams showing the importance of mold in forming soil.
Read more about this book at Wikipedia.