I want to know the answer to the following question:
Which book did Darwin begin reading in 1838?
All the background I'm provided with is that "Darwin related this to the struggle for existence among wildlife and botanist de Candolle's "warring of the species" in plants; he immediately envisioned "a force like a hundred thousand wedges" pushing well-adapted variations into "gaps in the economy of nature", so that the survivors would pass on their form and abilities, and unfavourable variations would be destroyed.". Is that enough to answer the question?