Possible source material for a Gaslight-era Cthulhu campaign. A free e-book from Project Gutenberg from 1823 called “Sketches in Bedlam: or Characteristic traits of insanity, as displayed in the cases of one hundred and forty patients of both sexes, now, or recently, confined in New Bethlem.”

The descriptions of the individual patients are quite sad, but the parts about how Bethlem Hospital (better known as Bedlam) worked in the 19th century might be useful for anyone running a Lovecraftian game in that era.

https://gutenberg.org/ebooks/79350