“Not in consequence of what I gave him!” Isaacson said.

“It must have been.”

“It was certainly not.”

“He never had such a night before—­never, till you interfered with him, and interrupted Doctor Hartley’s treatment.”

“Disgraceful!” exclaimed the young doctor.  “I never have heard of such conduct.  If it were ever to be made public, your medical reputation would be ruined.”

“And I shouldn’t mind if it was, over that!” said Isaacson.

His fingers no longer crushed the brim of his hat, but held it gently.

“I shouldn’t mind if it was.  But I think if very great care is not taken with this case, it will not be my medical reputation that will be ruined over it.”

As if mechanically Mrs. Armine pulled at the chair which she was holding.  She drew it nearer her, and twisted it a little round.

“What do you mean?” said Doctor Hartley.

“Mr. Armine is a well-known man.  Almost all the English travellers on the Nile, and most people of any importance in Cairo, know of his illness—­have heard about his supposed sunstroke.”

“Supposed!” interrupted the young doctor, indignantly.  “Supposed!”

“All these people will know the name of the medical man in charge of the case—­the medical man who declined a consultation.”

“Will know?” said Hartley.

Under the attack of Isaacson’s new manner his self-possession seemed slightly less assured.

“I shall be in Assouan and Cairo presently,” said Isaacson.

Mrs. Armine yawned and pulled at the chair.  Her face twitched under her veil.  She looked almost terribly alive, as if indeed her mind were in a state of ferment.  Yet there was in her aspect also a sort of half-submerged sluggishness.  Despite her vindictive agitation, her purposeful venom, she seemed already partially bound by a cloud of sleep.  That she had cast away her power to charm as useless was the greatest tribute that Isaacson had ever had paid to his seeing eyes.

“Really!  What has that to do with me?  Do you suppose I am attending this case surreptitiously?” said Hartley.

He forced a laugh.

“No; but I think it very possible that you may regret ever having had anything to do with it.”

In spite of himself, the young doctor was impressed by this new manner of the older man.  For a moment he was partially emancipated from Mrs. Armine.  For a moment he was rather the rising, not yet risen, medical man than the fully risen young man in love with a fascinating woman.  When he chose, Isaacson could hold almost anybody.  That was part of the secret of his success as a doctor.  He could make himself “believed in.”

“Some mistakes ring through the world,” Isaacson added quietly.  “I should not care to be the doctor who made one of them.”

Mrs. Armine, with a sharp movement, twisted the chair quite round, pulled at one side of her dress, and sat down.