John Scott Haldane CH FRS[1] (/ˈhɔːldeɪn/; 2 May 1860 – 14/15 March 1936) was a Scottish physician physiologist and philosopher famous for intrepid self-experimentation which led to many important discoveries about the human body and the nature of gases.

[3] Haldane locked himself in sealed chambers breathing potentially lethal cocktails of gases while recording their effect on his mind and body.

[2][5] When the Germans used poison gas in World War I, Haldane went to the front at the request of Lord Kitchener and attempted to identify the gases being used.

After the birth of Naomi, the family lived for a time in a house at 10 Randolph Crescent in Edinburgh's New Town before returning to Oxford.

[4] The mathematical model on which these tables were based, though considerably revised and modified, remains a widely accepted method of decompressing divers from non-saturation exposures.

He investigated numerous mine disasters, especially the toxic gases which killed most miners after firedamp and coal dust explosions.

Although electronic gas detectors are now used widely in all coal mines, flame lamps are still used extensively for their ease and simplicity of operation.

He identified carbon monoxide as the lethal constituent of afterdamp, the gas created by combustion, after examining many bodies of miners killed in pit explosions.

[4] In the late 1890s, Haldane introduced the use of small animals for miners to detect dangerous levels of carbon monoxide underground, either white mice or canaries.

With a faster metabolism, they showed the effects of poisoning before gas levels became critical for the workers, and so gave an early warning of the problem.

One surprising result of his analysis of the air in the sewers beneath the House of Commons was to show that the level of bacterial contamination was relatively low.

[4] During this research, he investigated fatalities of workmen in a sewer, and showed that hydrogen sulfide gas poisoning was the cause of death.