He survived concentrations of carbon monoxide in the blood that would, as his biographer notes, have looked entirely plausible as the 'cause of death' on a death certificate. 'Dry air,' Goodman writes, 'he could withstand to an astounding high of 300F, though if he moved about too much his hair began to singe.' Working in 99F 'dry bulb' heat, on one occasion, a colleague gave up after half an hour with a rectal temperature of 102.4F; Haldane went on for another 30 minutes. He spent hours and hours breathing toxic air and taking careful, methodical notes of its effects. He gassed himself with chlorine, methane, carbon dioxide, carbon monoxide, pure oxygen, nitrogen, mustard gas and god knows what else in various combinations... you name it, he turned blue and passed out on it. And, typically, no sooner had he come back round than he returned to the chamber to have another go.