Medical experiments done by physicians upon themselves (autoexperiments) have never evoked disapprobation, but rather have excited admiration, and yet it is curious that, of those recorded, some of the most dangerous were intended to prove, and were supposed to have proved, theories that are now known to be entirely incorrect.
In 1767 John Hunter infected himself with syphilis in an attempt to prove that it and gonorrhoea were the same disease. In 1835 Antoine-Barthelemy Clot tried to prove that the plague was not communicable by inoculating his arm with pus from a plague patient. And in 1892 Max von Pettenkofer swallowed live culture of Cholera vibrios in an attempt to show that they alone could not cause the disease. In the second half of the 20th century medical auto-experimentation has been largely confined to investigations of hallucinogenic and other psychotropic drugs.