But how could he take a holiday in the spring, just when everybody was coming to town?  Then he told himself that he was saying nonsense to himself.  People went abroad in the spring, to India, Sicily, the Riviera, the Nile.  Ah, he was back again on the Nile!  But so many people did not go abroad.  It would be madness for a fashionable doctor to be away just when the season was coming on.  Well, but he might run out for a very short time—­for a couple of weeks, something like that.  Two nights from London to Naples; two nights at sea in one of the new, swift boats, the Heliopolis, perhaps; a few hours in the train, and he would be at Cairo.  Five nights’ travelling would bring him to the first cataract.  And he would be in the real light.

He stared at the electric bulbs that gleamed on either side of the mantelpiece.  Then he glanced towards the windows, oblongs of dingy grey looking upon fog and daylight darkness.

That would be good, to be in the real light!

Nigel’s letter lay somewhere under the letters from patients.  The Doctor went back to his table, searched for it, and found it.  Then he came back to the fire, and studied the letter carefully again.

“Do you remember our walk home from the concert that night, and how I said, ‘I want to get into the light, the real light’?  Well, I’m in it, and how I wish that you and every one else could be in it too!...  Come to the Nile when next you take a holiday.”

It was almost an invitation to go; not quite an invitation, but almost.  Isaacson seemed to divine that the man who wrote wished his friend to come out and see his happiness, but that he did not quite dare to ask him to come out; seemed to divine a hostile influence that kept the pen in check.

“I wonder if she knows of this letter?”

That question came into Isaacson’s mind.  The last words of the letter almost implied that she knew.  Nigel had meant to tell her of it, had doubtless told her of it on the day when he wrote it.  If Isaacson went to the Nile, there was one person on the river who would not welcome him.  He knew that well.  And Nigel, of course, did not really want him.  Happy people do not really want friends outside to come into the magic circle and share their happiness.  They may say they do, out of good-will.  Even for a moment, moved by an enthusiastic impulse, they may think that they do.  But true happiness is exquisitely exclusive in its desires.

“Armine would like me just to see it’s all right, and then, when I’ve seen, he would like to kick me out.”

That was how Isaacson summed up eventually Nigel’s exact feeling towards him at this moment.  It was hardly worth while undertaking the journey from England to gratify such a desire of the happy egoist.  Better put the idea away.  It was impracticable, and—­

“Besides, it’s quite out of the question!”

The Doctor returned to his table, and began resolutely to write answers to his letters, and to fix appointments.  He went on writing until every letter was answered—­every letter but Nigel Armine’s.