While developing this intensive study of transmutation, Darwin became mired in more work.
Still rewriting his Journal, he took on editing and publishing the expert reports on his collections, and with Henslow's help obtained a Treasury grant of £1,000 to sponsor this multi-volume Zoology of the Voyage of H.M.S. Beagle, a sum equivalent to about £92,000 in 2018.
He stretched the funding to include his planned books on geology, and agreed to unrealistic dates with the publisher.
As the Victorian era began, Darwin pressed on with writing his Journal, and in August 1837 began correcting printer's proofs.

As Darwin worked under pressure, his health suffered.
On 20 September he had "an uncomfortable palpitation of the heart", so his doctors urged him to "knock off all work" and live in the country for a few weeks.
After visiting Shrewsbury he joined his Wedgwood relatives at Maer Hall, Staffordshire, but found them too eager for tales of his travels to give him much rest.
His charming, intelligent, and cultured cousin Emma Wedgwood, nine months older than Darwin, was nursing his invalid aunt.
His uncle Josiah pointed out an area of ground where cinders had disappeared under loam and suggested that this might have been the work of earthworms, inspiring "a new & important theory" on their role in soil formation, which Darwin presented at the Geological Society on 1 November 1837.

William Whewell pushed Darwin to take on the duties of Secretary of the Geological Society.
After initially declining the work, he accepted the post in March 1838.
Despite the grind of writing and editing the Beagle reports, Darwin made remarkable progress on transmutation, taking every opportunity to question expert naturalists and, unconventionally, people with practical experience in selective breeding such as farmers and pigeon fanciers.
Over time, his research drew on information from his relatives and children, the family butler, neighbours, colonists and former shipmates.
He included mankind in his speculations from the outset, and on seeing an orangutan in the zoo on 28 March 1838 noted its childlike behaviour.

The strain took a toll, and by June he was being laid up for days on end with stomach problems, headaches and heart symptoms.
For the rest of his life, he was repeatedly incapacitated with episodes of stomach pains, vomiting, severe boils, palpitations, trembling and other symptoms, particularly during times of stress, such as attending meetings or making social visits.
The cause of Darwin's illness remained unknown, and attempts at treatment had only ephemeral success.

On 23 June, he took a break and went "geologising" in Scotland.
He visited Glen Roy in glorious weather to see the parallel "roads" cut into the hillsides at three heights.
He later published his view that these were marine raised beaches, but then had to accept that they were shorelines of a proglacial lake.

Fully recuperated, he returned to Shrewsbury in July.
Used to jotting down daily notes on animal breeding, he scrawled rambling thoughts about marriage, career and prospects on two scraps of paper, one with columns headed "Marry" and "Not Marry".
Advantages under "Marry" included "constant companion and a friend in old age ... better than a dog anyhow", against points such as "less money for books" and "terrible loss of time."
Having decided in favour of marriage, he discussed it with his father, then went to visit his cousin Emma on 29 July.
He did not get around to proposing, but against his father's advice he mentioned his ideas on transmutation.
While developing this intensive study of transmutation, Darwin became mired in more work. Still rewriting his Journal, he took on editing and publishing the expert reports on his collections, and with Henslow's help obtained a Treasury grant of £1,000 to sponsor this multi-volume Zoology of the Voyage of H.M.S. Beagle, a sum equivalent to about £92,000 in 2018. He stretched the funding to include his planned books on geology, and agreed to unrealistic dates with the publisher. As the Victorian era began, Darwin pressed on with writing his Journal, and in August 1837 began correcting printer's proofs.
As Darwin worked under pressure, his health suffered. On 20 September he had "an uncomfortable palpitation of the heart", so his doctors urged him to "knock off all work" and live in the country for a few weeks. After visiting Shrewsbury he joined his Wedgwood relatives at Maer Hall, Staffordshire, but found them too eager for tales of his travels to give him much rest. His charming, intelligent, and cultured cousin Emma Wedgwood, nine months older than Darwin, was nursing his invalid aunt. His uncle Josiah pointed out an area of ground where cinders had disappeared under loam and suggested that this might have been the work of earthworms, inspiring "a new & important theory" on their role in soil formation, which Darwin presented at the Geological Society on 1 November 1837.
William Whewell pushed Darwin to take on the duties of Secretary of the Geological Society. After initially declining the work, he accepted the post in March 1838. Despite the grind of writing and editing the Beagle reports, Darwin made remarkable progress on transmutation, taking every opportunity to question expert naturalists and, unconventionally, people with practical experience in selective breeding such as farmers and pigeon fanciers. Over time, his research drew on information from his relatives and children, the family butler, neighbours, colonists and former shipmates. He included mankind in his speculations from the outset, and on seeing an orangutan in the zoo on 28 March 1838 noted its childlike behaviour.
The strain took a toll, and by June he was being laid up for days on end with stomach problems, headaches and heart symptoms. For the rest of his life, he was repeatedly incapacitated with episodes of stomach pains, vomiting, severe boils, palpitations, trembling and other symptoms, particularly during times of stress, such as attending meetings or making social visits. The cause of Darwin's illness remained unknown, and attempts at treatment had only ephemeral success.
On 23 June, he took a break and went "geologising" in Scotland. He visited Glen Roy in glorious weather to see the parallel "roads" cut into the hillsides at three heights. He later published his view that these were marine raised beaches, but then had to accept that they were shorelines of a proglacial lake.
Fully recuperated, he returned to Shrewsbury in July. Used to jotting down daily notes on animal breeding, he scrawled rambling thoughts about marriage, career and prospects on two scraps of paper, one with columns headed "Marry" and "Not Marry". Advantages under "Marry" included "constant companion and a friend in old age ... better than a dog anyhow", against points such as "less money for books" and "terrible loss of time." Having decided in favour of marriage, he discussed it with his father, then went to visit his cousin Emma on 29 July. He did not get around to proposing, but against his father's advice he mentioned his ideas on transmutation.
Charles Darwin