Oscillatory Thoughts has a brilliant post about the self-experimentation carried out by pioneering neurologist Henry Head in the early 1900s. This involved severing nerves to see which were responsible for areas of sensation and creating a thorough map of how sensory abilities differed across the body – and no spot was left untested.
The post has a fantastic description of a 1908 study on how somatosensation recovered after… ok, ok, here’s where he dips his cock in hot water:
In the case of [Henry Head], the tip happens to be devoid of heat-spots but is sensitive to cold and to pain. When… it was dipped into water at 40° C, no sensation of heat was produced, but [Head] experienced an unusually disagreeable sensation of pain… But, as soon as the water covered the corona without reaching the foreskin, both cold and pain disappeared, giving place to an exquisitely pleasant sensation of heat.
Science. Happy now?