"Do none suggest themselves? You know my methods. Apply them!"

"I can only think of the obvious conclusion that the man has
practised in town before going to the country."

"I think that we might venture a little farther than this. Look
at it in this light. On what occasion would it be most probable
that such a presentation would be made? When would his friends
unite to give him a pledge of their good will? Obviously at the
moment when Dr. Mortimer withdrew from the service of the hospital
in order to start a practice for himself. We know there has been
a presentation. We believe there has been a change from a town
hospital to a country practice. Is it, then, stretching our
inference too far to say that the presentation was on the occasion
of the change?"

"It certainly seems probable."

"Now, you will observe that he could not have been on the staff
of the hospital, since only a man well-established in a London
practice could hold such a position, and such a one would not
drift into the country. What was he, then? If he was in the
hospital and yet not on the staff he could only have been a
house-surgeon or a house-physician--little more than a senior
student. And he left five years ago--the date is on the stick.
So your grave, middle-aged family practitioner vanishes into thin
air, my dear Watson, and there emerges a young fellow under thirty,
amiable, unambitious, absent-minded, and the possessor of a
favourite dog, which I should describe roughly as being larger
than a terrier and smaller than a mastiff."