“Two years later I had to reconsider my position, for my revenge was being taken out of my hands.  Mark began to drink.  Could I have stopped him?  I don’t think so, but to my immense surprise I found myself trying to.  Instinct, perhaps, getting the better of reason; or did I reason it out and tell myself that, if he drank himself to death, I should lose my revenge?  Upon my word, I cannot tell you; but, for whatever motive, I did genuinely want to stop it.  Drinking is such a beastly thing, anyhow.

“I could not stop him, but I kept him within certain bounds, so that nobody but myself knew his secret.  Yes, I kept him outwardly decent; and perhaps now I was becoming like the cannibal who keeps his victim in good condition for his own ends.  I used to gloat over Mark, thinking how utterly he was mine to ruin as I pleased, financially, morally, whatever way would give me most satisfaction.  I had but to take my hand away from him and he sank.  But again I was in no hurry.

“Then he killed himself.  That futile little drunkard, eaten up with his own selfishness and vanity, offered his beastliness to the truest and purest woman on this earth.  You have seen her, Mr. Gillingham, but you never knew Mark Ablett.  Even if he had not been a drunkard, there was no chance for her of happiness with him.  I had known him for many years, but never once had I seen him moved by any generous emotion.  To have lived with that shrivelled little soul would have been hell for her; and a thousand times worse hell when he began to drink.

“So he had to be killed.  I was the only one left to protect her, for her mother was in league with Mark to bring about her ruin.  I would have shot him openly for her sake, and with what gladness, but I had no mind to sacrifice myself needlessly.  He was in my power; I could persuade him to almost anything by flattery; surely it would not be difficult to give his death the appearance of an accident.

“I need not take up your time by telling you of the many plans I made and rejected.  For some days I inclined towards an unfortunate boating accident in the pond—­Mark, a very indifferent swimmer, myself almost exhausted in a gallant attempt to hold him up.  And then he himself gave me the idea, he and Miss Norris between them, and so put himself in my hands; without risk of discovery, I should have said, had you not discovered me.

“We were talking about ghosts.  Mark had been even more vain, pompous and absurd than usual, and I could see that Miss Norris was irritated by it.  After dinner she suggested dressing up as a ghost and frightening him.  I thought it my duty to warn her that Mark took any joke against himself badly, but she was determined to do it.  I gave way reluctantly.  Reluctantly, also, I told her the secret of the passage. (There is an underground passage from the library to the bowling-green.  You should exercise your ingenuity, Mr. Gillingham, in trying to discover it.  Mark came upon it by accident a year ago.  It was a godsend to him; he could drink there in greater secrecy.  But he had to tell me about it.  He wanted an audience, even for his vices.)