“Please don’t speak of anything of that kind!” he said.

“I know I can never compensate you for all you’ve done for us—­”

“Oh, yes, you can!”

The Doctor’s voice was almost sharp.  Nigel was startled by it.

“We can?  How?”

“You can!” Isaacson said, laying a heavy stress on the first word.

“How?”

“First, by never speaking to me of—­of the usual ‘compensation’ patients make to doctors.”

“But how can you expect me to accept all this devoted service and make no kind of return?”

“Perhaps you can make me a return—­the only return I want.”

“But what is it?”

“I—­I won’t tell you to-night.”

“Then when will you tell me?”

Isaacson hesitated.  His face was blazing with expression.  He looked like a man powerfully stirred—­almost like a man on the edge of some outburst.

“I won’t tell you to-night,” he repeated.

“But you must tell me.”

“At the proper time.  You asked me at dinner what had been the matter with you, what illness you had been suffering from.  You observed that I didn’t care to tell you then.  Well, I’ll tell you before you get rid of me.”

“Get rid of you!”

“Yes, yes.  Don’t think I misunderstand what you’ve been trying to tell me to-night.  You want to convey to me in a friendly manner that now I’ve accomplished my work it’s time for me to be off.”

Nigel was deeply hurt.

“Nothing of the sort!” he said.  “It was only that my wife had made me understand what a terrible loss to you remaining out here at such a time must be.”

“There is something I must make you understand, Armine, before I leave you.  And when I’ve told you what it is, you can give me the only compensation I want, and I want it badly—­badly!”

“And you won’t tell me what it is now?”

“Not to-night—­not in a hurry.”

He got up.

“When are you expecting Mrs. Armine back?” he asked.

“In four nights.  She wants a couple of full days in Cairo.  Then there are the two night journeys.”

“I’ll tell you before she comes back.”

Isaacson turned round, and strolled away into the darkness of the garden.

When he was alone there, he tacitly reproached himself for his vehemence of spirit, for the heat of his temper.  Yet surely they were leading him in the right path.  These words of Nigel had awakened him to the very simple fact that this association must come to an end, and almost immediately.  He had been, he supposed now, drifting on from day to day, postponing any decision.  Mrs. Armine was stronger than he.  From her, through Nigel, had come to him this access of determination, drawn really from her decision.  As he knew this, he was able secretly to admire for a moment this woman whom he actively hated.  Her work in the dark would send him now to work in the light.