The young man, who seemed not to be perfectly sober, stumbled into the hall; and at the same moment the doctor came out of Quinton’s study, shutting the door and beginning to put on his gloves.

“See Mr. Quinton?” said the doctor coolly.  “No, I’m afraid you can’t.  In fact, you mustn’t on any account.  Nobody must see him; I’ve just given him his sleeping draught.”

“No, but look here, old chap,” said the youth in the red tie, trying affectionately to capture the doctor by the lapels of his coat.  “Look here.  I’m simply sewn up, I tell you.  I—­”

“It’s no good, Mr. Atkinson,” said the doctor, forcing him to fall back; “when you can alter the effects of a drug I’ll alter my decision,” and, settling on his hat, he stepped out into the sunlight with the other two.  He was a bull-necked, good-tempered little man with a small moustache, inexpressibly ordinary, yet giving an impression of capacity.

The young man in the billycock, who did not seem to be gifted with any tact in dealing with people beyond the general idea of clutching hold of their coats, stood outside the door, as dazed as if he had been thrown out bodily, and silently watched the other three walk away together through the garden.

“That was a sound, spanking lie I told just now,” remarked the medical man, laughing.  “In point of fact, poor Quinton doesn’t have his sleeping draught for nearly half an hour.  But I’m not going to have him bothered with that little beast, who only wants to borrow money that he wouldn’t pay back if he could.  He’s a dirty little scamp, though he is Mrs. Quinton’s brother, and she’s as fine a woman as ever walked.”

“Yes,” said Father Brown.  “She’s a good woman.”

“So I propose to hang about the garden till the creature has cleared off,” went on the doctor, “and then I’ll go in to Quinton with the medicine.  Atkinson can’t get in, because I locked the door.”

“In that case, Dr. Harris,” said Flambeau, “we might as well walk round at the back by the end of the conservatory.  There’s no entrance to it that way, but it’s worth seeing, even from the outside.”

“Yes, and I might get a squint at my patient,” laughed the doctor, “for he prefers to lie on an ottoman right at the end of the conservatory amid all those blood-red poinsettias; it would give me the creeps.  But what are you doing?”

Father Brown had stopped for a moment, and picked up out of the long grass, where it had almost been wholly hidden, a queer, crooked Oriental knife, inlaid exquisitely in coloured stones and metals.

“What is this?” asked Father Brown, regarding it with some disfavour.

“Oh, Quinton’s, I suppose,” said Dr. Harris carelessly; “he has all sorts of Chinese knickknacks about the place.  Or perhaps it belongs to that mild Hindoo of his whom he keeps on a string.”

“What Hindoo?” asked Father Brown, still staring at the dagger in his hand.