e was discredited. Nevertheless, he continued his
experiments with the aid of his principal assistant, a man named
Slavatsky.

"Sweigert's theory was that intellectuality, brain power,
intelligence, call it what you will, was the result of the presence of
a fluid which he called 'menthium' in the brain. He thought that it
could be transferred from one person to another, and with the aid of
Slavatsky, he experimented on himself. He removed the menthium from an
unfortunate victim, who was reduced to a state of imbecility, and
Slavatsky injected the substance into Sweigert's brain. The experiment
resulted fatally and Slavatsky was tried for murder. He was acquitted
of intentional murder but was imprisoned for a time for manslaughter.
He was released when the Austro-Hungarian Empire was broken up, and
for a time I lost track of him.

"I found translations of both the records of the trials and of
Sweigert's original reports, and the thing that attracted my attention
was that the puncture I found in the victim corresponded exactly with
the puncture described by Sweigert as the one he made in extracting
the menthium. I asked the immigration authorities to check over their
records and they found that a man named Slavatsky whose description
corresponded with the ill-fated Sweigert's assistant had entered the
United States under Austria's quota about a year ago. The chain of
evidence seemed complete to me, and it only remained to find the man
who was systematically robbing brains.

"If such a thing was really going on, I felt that my reputation would
make me an attractive bait and I secured a double, as you know, and
placed him in a position where his kidnapping would be an easy matter.
I was sure that the victims were being taken away by air and that
lethane was being used to reduce the neighborhood to a state of
profound somnolence, so I hid myself near my double with a gas
detector which would find even minute traces of lethane in the air.

"My fish rose to the lure and came after the bait last night. When his
ship arrived, I found a strange gas in the air, and followed the ship
by the trail of the substance which it left behind it. Carnes was with
me, and we got here in time to witness the extraction of the menthium
from my friend, Professor Williams of Yale, and to see it injected
into one of Slavatsky's gang. I sent Carnes for help and messed around
until I was captured myself--and help arrived just in time. That's
abo