Through his research, John Scott Haldane became an international authority on ether and respiration and was famous for self experimentation – locking himself in sealed chambers breathing potentially lethal cocktails of gases while recording their effect on his mind and body.
John married Louisa Kathleen Coutts Trotter (1863–1961) in December 1891. She was the daughter of Coutts Trotter FRGS and Harriet Augusta Keatinge. They had two children – a son J. B. S. Haldane, who served in WW1 and became a scientist - and Naomi, who became a writer and wrote using her married name of Mitchison. His nephew was the New Zealand doctor and public health administrator Robert Haldane Makgill.
When the Germans used poison gas during the First World War, John travelled to the Western Front at the request of Lord Kitchener to try to identify the gases being used. One outcome of this was his invention of a respirator, known as the black veil - an early gas mask After being forced out of combatting poison gases in WWI due to alleged German sympathies, he began working with victims of gas warfare and developed oxygen treatment including the oxygen tent.
After John’s death in March 1936, the poet Sir Henry Newbolt wrote this poem:
"For J. S. Haldane"
SILENT Moon and silent morning air,
Silver frost on green and silver lawn,
Shimmering mist in downland hollows bare,
Magical night dying in timeless dawn—
O Earth, Earth, Earth! what needs this loveliness
To quiet a graveyard of unnumbered clods?
Is thy bread truth, or we that break and bless?
Shall we not live at last, when we are Gods?
Sir Henry Newbolt 1937, published in Newbolt’s collection “A Perpetual Memory and other Poems” With brief memoirs by Walter de la Mare and Ralph Furse (Murray, 1939).