单选题 .  I entered St. Thomas's Hospital as a medical student at the age of 18 and spent five years there. I was an unsatisfactory student, for my heart was not in it. I had always wanted to be a writer, and in the evenings, after my tea, I wrote and read. Before long, I wrote a novel, called Liza of Lambeth, which I sent to the publisher and was accepted. It appeared during my last year at the hospital and had something of a success. I felt I could afford to give up medicine and make writing my profession; so, three days after I graduated from the school of medicine, I set out for Spain to write another book. Looking back now, and knowing the terrible difficulties of making a living by writing, I realize I was taking a fearful risk.
    The next ten years were very hard, and I earned an average of ￡100 a year. Then I had a bit of luck. The manager of the Court Theatre put on a play that failed; the next play he had arranged to put on was not ready, and he was at his wits' end. He read a play of mine and, though he did not much like it, he thought it might just run for the six weeks till the play he had in mind to follow it with could be produced. It ran for fifteen months. Within a short while, I had four plays running in London at the same time. Nothing of the kind had ever happened before. I was the talk of the town.1.  When the author was a medical student, he ______.