better take a proper copy of this."

"Then the cabman wasn't Max?" cried Sowerby eagerly. "I thought not."

"I believe you told me so before," said Dunbar sourly. "I also seem to
recall that you thought a scorpion's tail was a Prickly Pear.
However--here, on the page numbered twenty-six, is a description of
the woman known as Mlle. Dorian. It should be a fairly easy matter to
trace the car through the usual channels, and she ought to be easy to
find, too."

He glanced at his watch. Stuart was standing by the lofty window
looking out across the Embankment.

"Ten o'clock," said Dunbar. "The Commissioner will be expecting us."

"I am ready," responded Stuart.

Leaving Sergeant Sowerby seated at the table studying the note-book,
Stuart and Dunbar proceeded to the smoke-laden room of the Assistant
Commissioner. The great man, suavely satanic, greeted Stuart with
that polished courtesy for which he was notable.

"You have been of inestimable assistance to us in the past, Dr.
Stuart," he said, "and I feel happy to know that we are to enjoy the
aid of your special knowledge in the present case. Will you smoke one
of my cigarettes? They are some which a friend is kind enough to
supply to me direct from Cairo, and are really quite good."

"Thanks," replied Stuart. "May I ask in what direction my services
are likely to prove available?"

The Commissioner lighted a fresh cigarette. Then from a heap of
correspondence he selected a long report typed upon blue foolscap.

"I have here," he said, "confirmation of the telegraphic report
received last night. The name of M. Gaston Max will no doubt be
familiar to you?"

Stuart nodded.

"Well," continued the Commissioner, "it appears that he has been
engaged in England for the past month endeavouring to trace the
connection which he claims to exist between the sudden deaths of
various notable people, recently--a list is appended--and some person
or organisation represented by, or associated with, a scorpion. His
personal theory not being available--poor fellow, you have heard of
his tragic death--I have this morning consulted such particulars as
I could obtain respecting these cases. If they were really cases of
assassination, some obscure poison was the only mode of death that
could possibly have been employed. Do you follow me?"

"Perfectly."

"Now, the death of Gaston Max under circumstances not yet explained,
would seem to indicate that his theory was a sound one. In o