The record by the surgeon of the amputation of Nelson's arm and subsequent medication is held by the National Archives. A quick way to access this is on the website of the Woodland Trust
www.treeforall.org.uk/ then click on 'About Nelson' on the left and scroll down.
It is well known that, for Nelson, the memory of the cold steel cutting into flesh rather than the gruesome sawing through bone was the most excruciating memory, and that, ever afterwards he instructed his surgeons to warm their instruments. I wonder if this was an unwittingly beneficial action in that boiling water, if it was used, would have sterilised the instruments. Certainly, at Trafalgar, there were 11 amputations in Victory and only one man subsequently died - he, I believe, was the heroic James Maine. As his arm was amputated, 'he sang every verse of 'Rule Britannia' in a loud clear voice.'