The scientists conducted over 600 experiments on themselves, breathing CO2, oxygen, and more gases. download the app Email address Sign up By clicking “Sign Up”, you accept our Terms of Service and Privacy Policy . Hulton-Deutsch Collection/CORBIS/Corbis via Getty ImagesThe seizures were bad enough in a dry hyperbaric chamber, but one of the researchers nearly drowned breathing oxygen while submerged in water. AdvertisementOne of the British X-Craft submarines that required special calculations about how long it could be under the water without resurfacing for fresh air. Their dangerous experiments not only contributed to the D-Day invasion, but also contributed to the science behind modern-day scuba diving.

---

Persons: —, Rachel Lance, Bettmann, John Burdon Sanderson Haldane, Haldane, Thetis, John Haldane, Hulton, Martin Case Organizations: British Admiralty, Service, Channel, British Army, intel, Royal Navy, British Royal Navy, Getty, University College London, Deutsch Locations: Normandy