has observed two patients who recovered.
But the majority of cases where orosin has been administered were
found incurable. The mind is blank, the memory completely destroyed,
and the general health so undermined that only the strongest persons
can withstand the strain."

At once I described Gabrielle's symptoms and general attitude,
whereupon the Professor said:

"What you tell me are the exact symptoms exhibited by a person to whom
a small dose of orosin has been administered. In most cases, however,
such a state of mind develops into actual insanity with a homicidal
tendency. Such a patient should be very carefully watched, for in
ninety per cent. the chance of a cure is, alas! beyond expectation."

CHAPTER THE EIGHTEENTH

MORE ABOUT THE MYSTERY-MAN

One very important fact I had established. Orosin was the obscure and
little-known drug that had been administered to Gabrielle Tennison, as
well as to myself, by the mystery-man of Europe at his palatial house
in Stretton Street. Gabrielle being the weaker, was still suffering
from its paralysing effects, while I, the stronger, had practically
recovered.

Yet it had been intended by the daring Despujol that a fatal
"accident" should now befall me! And could anything be plainer than
that the fellow for whom the police were searching so eagerly was a
hireling of the man De Gex who went in fear of me?

That most secret and most potent of all poisons might be known to
Moroni! Indeed, it apparently was known to him, and the endeavour had
been to introduce it into my system by means of an infected carpet
pin.

On leaving Professor Vega I at once sent a note round to Hambledon,
and awaited his arrival.

When he came I related all the professor had told me.

"Well, Hugh," he said, "we now know the truth, and it remains for us
to combat the fiends. If you are marked down--no doubt I am also. So
it behoves us both to be very wary."

"Why can't we tell the police the whole circumstances?" I suggested.

"My dear fellow, they wouldn't believe you, and they wouldn't arrest
such a powerful man as Oswald De Gex," was his serious reply. "Money
can buy immunity from arrest in every country in Europe, and
especially De Gex's money, for it can be distributed in secret by his
agents. No. If we are to be successful we must lay our plans just as
cleverly as he lays his. We must allow him to believe that we are
entirely unsuspicious of his plotting. That is our only wa