A light dawned on Flambeau’s face, and he said:  “There was something else written by Quinton, some other words. `They will tell you I die by my own hand,’ or `Do not believe that—­’”

“Hotter, as the children say,” said his friend.  “But the piece was hardly half an inch across; there was no room for one word, let alone five.  Can you think of anything hardly bigger than a comma which the man with hell in his heart had to tear away as a testimony against him?”

“I can think of nothing,” said Flambeau at last.

“What about quotation marks?” said the priest, and flung his cigar far into the darkness like a shooting star.

All words had left the other man’s mouth, and Father Brown said, like one going back to fundamentals: 

“Leonard Quinton was a romancer, and was writing an Oriental romance about wizardry and hypnotism.  He—­”

At this moment the door opened briskly behind them, and the doctor came out with his hat on.  He put a long envelope into the priest’s hands.

“That’s the document you wanted,” he said, “and I must be getting home.  Good night.”

“Good night,” said Father Brown, as the doctor walked briskly to the gate.  He had left the front door open, so that a shaft of gaslight fell upon them.  In the light of this Brown opened the envelope and read the following words: 

  Dear father brown,—­Vicisti Galilee.  Otherwise, damn your
  eyes, which are very penetrating ones.  Can it be possible that
  there is something in all that stuff of yours after all?

I am a man who has ever since boyhood believed in Nature and in all natural functions and instincts, whether men called them moral or immoral.  Long before I became a doctor, when I was a schoolboy keeping mice and spiders, I believed that to be a good animal is the best thing in the world.  But just now I am shaken; I have believed in Nature; but it seems as if Nature could betray a man.  Can there be anything in your bosh?  I am really getting morbid.

I loved Quinton’s wife.  What was there wrong in that?  Nature told me to, and it’s love that makes the world go round.  I also thought quite sincerely that she would be happier with a clean animal like me than with that tormenting little lunatic.  What was there wrong in that?  I was only facing facts, like a man of science.  She would have been happier.

According to my own creed I was quite free to kill Quinton, which was the best thing for everybody, even himself.  But as a healthy animal I had no notion of killing myself.  I resolved, therefore, that I would never do it until I saw a chance that would leave me scot free.  I saw that chance this morning.

I have been three times, all told, into Quinton’s study today.  The first time I went in he would talk about nothing but the weird tale, called “The Cure of a Saint,” which