Sherlock Series 3: 20 Canonical References You May Have Missed

15. DVD Salesman

The DVD salesman who John mistakenly thinks is Sherlock in disguise is a reference to The Adventure of the Empty House, where Sherlock surprises John by disguising himself as an elderly book dealer. The DVDs from The Empty Hearse also have the almost exact same titles of the books from The Adventure of the Empty House. John also asks the DVD salesman if his usual GP is named Dr. Verner, which is the name of Holmes' cousin who buys Watson's practice in The Adventure of the Norwood Builder.

14. Professor Presbury And Monkey Glands

While talking to some clients in The Empty Hearse, Sherlock quickly mentions monkey glands and an unseen character, Professor Presbury, both of which are references to The Adventure of the Creeping Man. Since you're probably wondering what monkey glands could mean, in The Adventure of the Creeping Man, Professor Presbury takes a drug that is an extract obtained from langurs, a type of monkey.

13. Mary Reading John's Blog

In the Empty Hearse, Mary reads one of John's blog posts aloud, which happens to be an almost verbatim excerpt from chapter six of The Sign of Four.

"So swift, silent, and furtive were his movements, like those of a trained blood-hound picking out a scent, that I could not but think what a terrible criminal he would have made had he turned his energy and sagacity against the law, instead of exerting them in its defence."