Sir Henry Duncan Littlejohn was born May 8, 1826 in Edinburgh.
He studied medicine at the University of Edinburgh, graduating in 1847. He was Edinburgh’s first Medical Officer of Health, the city’s Police Surgeon, and co-founder of the Royal Hospital for Sick Children in Edinburgh. He acted as an expert witness in Scottish criminal cases. He was also a teacher of forensic medicine when Arthur Conan Doyle was studying at the University of Edinburgh.
He was knighted by Queen Victoria in 1895.
While many Sherlockians are familiar with the role Dr Joseph Bell played in the creation of Sherlock Holmes, in a 1929 speech, Arthur Conan Doyle also recognized the influence of Dr Bell’s colleague, Henry Duncan Littlejohn.
Source: A Curious Collection of Dates: Through the Year with Sherlock Holmes by Leah Guinn (JHWS “Amber”) and Jaime N Mahoney (JHWS “Tressa”)