J. S. Haldane ... I just couldn't let it lie

My first two copies of Suffer and Survive, my new biography of John Scott Haldane, arrived at my London home yesterday. My agent called to tell me how splendid they look. By chance I happened to be back in Edinburgh, fresh from scouting through the archives at the National Library of Scotland once again.
Now I know, a biographer has to learn to let go, to move on. So much stuff on Haldane once existed though - his own memoir, the biography by his sister - and I still have hopes of finding it. And I did manage one such triumph yesterday.
The letters from Haldane's colleague, C. Gordon Douglas, had gone missing. This was vital correspondence sent from the frontline, detailing the continued work of the pair in combatting gas warfare right through till the end of the war. It was once part of the Oxford Physiology Lab. I searched through their dusty boxes, and indeed had been through the National Library before, and subsequently had their staff launch a fruitless search.
Yesterday, for some reason, I came across it - a treasure trove, MS20034. A great haul of WW1 material, plus some fine letters from Jan Smuts about their work launching the concept of holism to a British Association meeting in South Africa in 1929. Fine touching things too, like a letter from Haldane's former cook.
Is it too late? Well of course this material does not get into this edition - and that does not matter. I felt the book was complete as is, with no holes to fill -a trip to Canada and some writing around gave me the information I needed to write the complete wartime story. I already had much more material for my book than I could fit in. It broadens my own background knowledge on the man thouh, and bolsters my argument for his vital role in gas protection during WW1. My delight is simply the researchers' reward, coming up trumps, finding a missing piece.

(Pictures are ones I took on my visit to Ypres - the memorial to the Canadian soldiers who lost their lives in the first gas attack, and the graves of some of those soldiers)