Celebrity Conundrum

“Watson,” Holmes said to me one day, “You like to keep in touch with the news, do you not? You are a fickle follower of fame and celebrity, and all that tittle and tattle from the society pages?”

“I suppose I do have a certain interest in the lives of others,” I replied cautiously, before adding, “And I might point out that you have occasionally benefitted from my knowledge of society.”

“Here’s a little puzzle you might enjoy, then,” he announced, before continuing with great pomp: “William Gladstone has a long one. Alexander Graham Bell has a short one. Queen Victoria doesn’t have one. Casanova always used his. The Pope never uses his.”

What was Holmes referring to?

SOLUTION