The Hound of the Baskervilles

Holmes did not deduce that the stick's owner was amn who'd just been married and had left the hospital to set up a practice.

“A presentation, I see,” said Holmes.

“Yes, sir.”

“From Charing Cross Hospital?”

“From one or two friends there on the occasion of my marriage.”

“Dear, dear, that’s bad!” said Holmes, shaking his head.

Dr. Mortimer blinked through his glasses in mild astonishment. “Why was it bad?”

“Only that you have disarranged our little deductions. Your marriage, you say?”

“Yes, sir. I married, and so left the hospital, and with it all hopes of a consulting practice. It was necessary to make a home of my own.”