"The rest follows, of course, by slow freight," he added tactfully, and
as naturally as possible. "But come, sir, you must be tired and in want
of food after your long journey. I'll get a taxi at once, and we can see
about the other luggage afterwards."

It seemed to him he hardly knew quite what he was saying; the change in
his friend had come upon him so suddenly and now grew upon him more and
more distressingly. Yet he could not make out exactly in what it
consisted. A terrible suspicion began to take shape in his mind,
troubling him dreadfully.

"I am neither very tired, nor in need of food, thank you," the professor
said quietly. "And this is all I have. There is no luggage to follow. I
have brought home nothing--nothing but what you see."

His words conveyed finality. They got into a taxi, tipped the porter,
who had been staring in amazement at the venerable figure of the
scientist, and were conveyed slowly and noisily to the house in the
north of London where the laboratory was, the scene of their labours of
years.

And the whole way Professor Ebor uttered no word, nor did Dr. Laidlaw
find the courage to ask a single question.

It was only late that night, before he took his departure, as the two
men were standing before the fire in the study--that study where they
had discussed so many problems of vital and absorbing interest--that
Dr. Laidlaw at last found strength to come to the point with direct
questions. The professor had been giving him a superficial and desultory
account of his travels, of his journeys by camel, of his encampments