discussion about his dealing with testicular cancer - which should be compulsory viewing for all my male readers because your life time risk is about 1:200 and it's treatable if diagnosed early. You have a spare! Ugly or not in the natural state, scrotal carcinomas are truly frightening to view and I'm now sorry to have encountered pictures in my research.
ANNyway, in 1775 Pott published his epidemiological findings and thus became the first person in modern(ish) medicine to identify an occupational malignancy caused by an environmental carcinogen. Actually John Hill could have been the first to identify an environmental carcinogen-of-lifestyle in noting that snuff takers were prone to hideously painful nasal cancers. Pott's hypothesis, which has stood up well over the last 250 years, is that the cancer "seems to derive its origin from a lodgement of soot in the rugae of the scrotum." to cause what medics now refer to as a squamous cell carcinoma. It's not all of the soot, of course, but a complex aromatic molecule called benzopyrene that causes the damage by jamming into and then mutating DNA in the affected cells which then grow out of control. Sam Kean has a nice essay bringing Pott and his carcinoma up to date by showing the involvement of lesions induced in the gene p53 on chromosome 17 of the human genome. Pott's report led directly to the Chimney Sweepers Act (1788) which required chimney-boys to be at least eight (8)! years old (and go to church on Sundays) but the practice of sending minors up chimneys wasn't finally outlawed in England until 1875.