actually, it was your reflection on the coffee service
Our first glimpse of Sherlock Holmes and Dr. Watson takes a look at a mysterious cane left by an unknown visitor in the office, and Watson says his friend must "have eyes in the back of his head" because he saw what he was doing.
Watson provides his hypothesis of the origin of the walking stick, suggesting that the inscription, « To James Mortimer, M.R.C.S., from his C.C.H. friends, » indicates an elderly physician who was awarded the item after years of faithful service.
Holmes congratulates Watson, and proceeds to study the cane itself while Watson enjoys compliments from Holmes. However, quickly contradicts Watson 's findings. Holmes suggests the owner is clearly a practitioner from the country and CCH actually means Charing Cross Hospital.