From I'm Nova - Cubitt (Dancing Men) gives Holmes for Christmas his relative (Mordecai Cubitt Cooke)'s book, "Rust, smut, mildew and mould. An introduction to the study of microscopic fungi." (6th edition, 1898, which is when Dancing Men takes place according to wikipedia.)

==Day One==
Fanmail

Watson grinned as he sorted through the post for the day. "Holmes?"

The detective barely looked up from where he was comfortably ensconced with his pipe and papers in his armchair. "Mm?"

"You've received another Christmas gift from another satisfied client." Still grinning, Watson walked over and deposited the parcel in his friend's lap.

"Not again," Holmes groaned. In the years since his return to London, he'd begun to receive Christmas cards from former clients and then actual gifts, ranging from books to magnifying lenses to every type of tobacco under the sun. He glanced down at the label. "Hilton Cubitt." He sighed in annoyance. "That was a most trivial matter—the case practically solved itself."

"You may have saved the man's life, Holmes," Watson reminded him. "Abe Slaney was a rough character."

Holmes waved a disparaging hand.

"Well, go on. Aren't you going to open it?"

Holmes glared up at his friend. "Only if you'll burn it for me once I've satisfied your curiosity."

Watson glanced heavenward. "If I must."

Holmes cut open the wrapping and pulled a leather-bound book out of it. "Rust, Smut, Mildew and Mould. An Introduction to the Study of Microscopic Fungi."

Watson picked up the card that had rested atop the book. "It's by a cousin of his: Mordecai Cubitt Cooke." The doctor was careful to hold back a triumphant smile. "Are you certain you want me to burn that, Holmes? It could prove useful."

"Perhaps," Holmes growled reluctantly around his pipe. "Really, Watson, you can stop biting back that smile—you are the most insufferable man when you are proven right!"

A/N: I'm so happy to be doing this again!