explain," he said, curtly.

The dining-room was in pitchy darkness, for the lights there had been on
the short circuit; indeed, the lights on the ground floor had all failed
with the exception of the hall, which fortunately had been on another
circuit. The fact had saved Van Sneck's life, for if Bell had not
speedily used that one live wire the patient must have perished.

Henson looked up from his sofa with a start and a smile.

"I am afraid I must have been asleep," he said, languidly.

"Liar," Bell thundered. "You have been plotting murder. And but for a
mere accident the plot would have been successful. You have worked out
the whole thing in your mind; you came here on purpose. You came here to
stifle the light at the very moment when we were operating on Van Sneck.
You thought that all the lights on the floor would be on the same
circuit; you have been here before."

"Are you mad?" Henson gasped. "When have I been here before--"

"The night that you lured Van Sneck here by a forged letter and left him
for dead."

Henson gasped, his lips moved, but no words came from them.

"You have a little knowledge of electricity," Bell went on. "And you saw
your way pretty clear to spoil our operation to-night. You got that idea
from yonder wall-plug, into which goes the plunger of the reading lamp on
the cabinet yonder. At the critical moment all you had to do was to dip
your fingers in water and press the tips of them against the live wire in
the wall-plug. You did so, and immediately the wires fired all over the
circuit and plunged us in darkness. But the hall light remained sound,
and Van Sneck was saved. If it is any consolation to you, he will be as
sensible as any of us to-morrow."

"Hensen had risen to his feet, pale and trembling, He protested, but it
was all in vain. Bell approached the china wall-plug and pointed to it.

"Hold the candle down," he said. "There! You can see that the surface is
still wet, there is water in the holes now, and some of it has trickled
down the distemper on the wall. You ought to be shot where you stand,
murderous dog."

Henson protested, with some dignity. It was all so much Greek to him, he
said. He had been sleeping so quietly that he had not seen the light
fail. Bell cut him short.

"Get out," he cried. "Go away; you poison the air that honest men
breathe, and you are as fit and well as I am. Why don't you pitch him
into the street, Steel? Why don't you telephone to Marle