ecame black and nauseous with spiders.

Half-way to the top Dr. Cairn turned, snatched out a revolver and
began firing down into the cellar in the direction of the sarcophagus.

A hairy, clutching thing ran up his arm, and his son, uttering a groan
of horror, struck at it and stained the tweed with its poisonous
blood.

They staggered to the head of the steps, and there Dr. Cairn turned
and hurled the candle at a monstrous spider that suddenly sprang into
view. The candle, still attached to its wooden socket, went bounding
down steps that now were literally carpeted with insects.

Tarantulas began to run out from the trap, as if pursuing the
intruders, and a faint light showed from below. Then came a crackling
sound, and a wisp of smoke floated up.

Dr. Cairn threw open the outer door, and the two panic-stricken men
leapt out into the street and away from the spider army. White to the
lips they stood leaning against the wall.

"Was it really--Ferrara?" whispered Robert.

"I hope so!" was the answer.

Dr. Cairn pointed to the closed door. A fan of smoke was creeping from
beneath it.

* * * * *

The fire which ensued destroyed, not only the house in which it had
broken out, but the two adjoining; and the neighbouring mosque was
saved only with the utmost difficulty.

When, in the dawn of the new day, Dr. Cairn looked down into the
smoking pit which once had been the home of the spiders, he shook his
head and turned to his son.

"If our eyes did not deceive us, Rob," he said, "a just retribution at
last has claimed him!"

Pressing a way through the surrounding crowd of natives, they returned
to the hotel. The hall porter stopped them as they entered.

"Excuse me, sir," he said, "but which is Mr. Robert Cairn?"

Robert Cairn stepped forward.

"A young gentleman left this for you, sir, half an hour ago," said the
man--"a very pale gentleman, with black eyes. He said you'd dropped
it."

Robert Cairn unwrapped the little parcel. It contained a penknife, the
ivory handle charred as if it had been in a furnace. It was his
own--which he had handed to his father in that awful cellar at the
moment when the first spider had dropped; and a card was enclosed,
bearing the pencilled words, "With Antony Ferrara's Compliments."

CHAPTER XVII

THE STORY OF ALI MOHAMMED

Saluting each of the three in turn, the tall Egyptian passed from Dr.
Cairn's room. Upon his exit followed