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." I laughed incredulously as Sherlock Holmes leaned back in his settee and blew little wavering rings of smoke up to the ceiling.
"As to the latter part, I have no means of checking you," said I, "but at least it is not difficult to find out a few particulars about the man's age and professional career." From my small medical shelf I took down the Medical Directory and turned up the name.