“Was Mr. Staunton a healthy man?”

“Absolutely.”

“Did you ever know him ill?”

“Never.”

Holmes popped a sheet of paper before the doctor’s eyes. “Then perhaps you will explain this receipted bill for thirteen guineas, paid by Mr. Godfrey Staunton last month to Dr. Leslie Armstrong, of Cambridge. I picked it out from among the papers upon his desk.”

The doctor flushed with anger.