“No, I shouldn’t put it down entirely to sunstroke.  Hartley wasn’t quite right there, I think.”

“Well, then?”

Nigel had found a safe topic for conversation, or thought he had.  It was sufficiently evident that he felt more at ease, and perhaps he was atoning for former indifference as to the cause of his misery by a real and keen interest about it now.

“You were unwell, you see, before you went out digging without a hat.  Weren’t you?”

“Yes, that bath in the Nile near Kous.  It seemed all to begin somewhere about then.  But d’you know, though I’ve never said so, even to you, I believe I really was not quite myself when I took that dip.  I think it was because of that I got the chill.”

“Very possibly.”

“When I started, I was splendidly well.  I mean when we went on board of the Loulia.  It’s as if it was something to do with that boat.  I believe I began to go down the hill very soon after we started on her.  But it was all so gradual that I scarcely noticed anything at first.  My bath made things worse, and then the digging fairly finished me.”

“Ah!”

The last course of the very light dinner was put on the table.  Isaacson poured out some Vichy water and began to squeeze the juice of half a lemon into it.  Nigel sat watching the process, which was very careful and deliberate.

“You don’t tell me what exactly has been the matter,” he said, at last.

“You’ve had such a complication of symptoms.”

“That you mean it’s impossible to give a name that covers them all?”

Isaacson squeezed the last drop almost tenderly into the tumbler, took up his napkin, and carefully dried his long, brown fingers.

“‘What’s in a name?’” he quoted.

He looked across the table at Nigel, and questions seemed to be shining in his eyes.

“Do you mean that you don’t want to tell me the name?” Nigel said.

It seemed that he was roused to persistence.  Either curiosity or some other feeling was awakened within him.

“I don’t say that.  But you know we doctors often go cautiously—­we don’t care to commit ourselves.”

“Hartley, yes.  But that isn’t true of you.”

He paused.

“You are hedging,” he said, bluntly.

Isaacson drank the Vichy and lemon.  He put down the glass.

“You are hedging,” Nigel repeated.  “Why?”

“Isn’t it enough for you to get well?  What good will it do you to know what you have been suffering from?”

“Good!  But isn’t it natural that I should wish to know?  Why should there be any mystery about it?”

He stopped.  Then, leaning forward a little with one arm on the table, he said: 

“Does my wife know what it is?”

“I’ve never told her,” Isaacson answered.

“Well, but does she know?”

The voice that asked was almost suspicious.  And the eyes that regarded Isaacson were now suspicious, too.