Who had studied the medicine in youth?

In his introduction to King's Solomon's Mines, Allan Quatermain sets out his reasons for writing about his great adventures. He is, after all, a wealthy man who's made a fortune from his various escapades and so certainly doesn't need the money. And as he also admits, Quatermain is not really much of a literary man, though he remains devoted to the Old Testament and the Ingoldsby Legends.
The main reason for writing his story is very simple and straightforward: Sir Henry Curtis and Captain John Good asked him to. Another reason is that Quatermain is laid up with a pain in his left leg after being attacked by a lion, and writing helps to break the monotony. The third reason he gives is that he wants to provide some entertainment for his son Harry, who's studying to be a doctor in London. Quatermain figures that his epic tale will provide a much-needed dash of color to a life rendered interminably dull by the deadening routine of hospital work.