Before Doyle became a writer he was a doctor and he set up office in Southsea, Portsmouth. He also published in the British Medical Journal and I found this article in the archive:
To summarize: Doyle was overdosing too many of his patients so he decided that he would see at what point overdose symptoms began and what they were. He did this by dosing himself regularly and seeing what happened! Now, I thought this was pretty crazy – who does this? Who, in their right mind, would think ‘I’m going to overdose myself, risk death, just to see what happens’? Well, Doyle did and with a bit of research, it seems a lot of others did too! There weren’t science labs in the same way there are now, and there weren’t any rules on using human test subjects. Not to mention patients were completely unreliable because the only measurement was their own account of their symptoms, which may not be accurate and was always subjective. The only way for doctors to know what happens, and to be able to describe it in medical terms, was to experiment on themselves.
There are plenty of examples:
The New Scientist have written an article called ‘Eight scientists who became their own guinea pigs‘
Cracked.com have one called ‘6 Most Badass Self-Inflicted Medical Experiments‘
Or HowStuffWorks also have an article called ‘10 Scientists Who Were Their Own Guinea Pigs‘
My favourite story (though perhaps favourite isn’t quite the word…grossest? Fascinating? Disturbing?) is from Cracked.com: Max Josef Von Pettenkofer was a 19th century medical researcher drank who CHOLERA bacteria made from a dead man’s diarrhea. Nice. The reason being he believed that bacteria alone would not cause chloera, it needed other variables such as dirty living conditions. He miraculously managed to avoid coming down with the disease and ended up being immortalised on a stamp. (After all, who doesn’t want to be on a stamp? Like Sherlock and Doyle here) I wouldn’t suggest replicating Pettenkofer’s experiment though…
A Study of Fandom 