Samuel Latham Mitchill was a New York lawyer, professor and physician. He discovered the anaesthetising properties of "gaseous oxide of azote" (nitrous oxide) inhalation in 1795, several years before Sir Humphry Davy. Mitchill tested the gas on numerous non-human animals, almost killing them in the process. Mitchill concluded that the root cause of all plague-like disease was exposure to nitrous oxide. His theory of contagion was at odds with the tenets of pnuematic medicine. Pneumatology enthusiasts like Thomas Beddoes believed that inhaling the newly-discovered gases and vapours would cure or alleviate disease rather than provoke it.