Heerden.

"A germicide factory," said van Heerden promptly.

"Suppose I know the character of this laboratory?" asked Beale quietly.

"Carry that kind of story to the police and see what steps they will
take," said van Heerden scornfully. "My dear Mr. Beale, as I have told
you once before, you have been reading too much exciting detective
fiction."

"Very likely," he said, "but anyhow the little story that enthralls me
just now is called the Green Terror, and I'm looking to you to supply a
few of the missing pages. And I think you'll do it."

The doctor was lighting a cigarette, and he looked at the other over the
flaring match with a gleam of malicious amusement in his eyes.

"Your romantic fancies would exasperate me, but for your evident
sincerity. Having stolen my bride you seem anxious to steal my
reputation," he said mockingly.

"That," said Beale, slipping off the bench and standing, hands on hips,
before the doctor, "would take a bit of finding. I tell you, van
Heerden, that I'm going to call your bluff. I shall place this factory
in the hands of the police, and I am going to call in the greatest
scientists in England, France and America, to prove the charge I shall
make against you on the strength of this!"

He held up between his forefinger and thumb a crystal tube, filled to
its seal with something that looked like green sawdust.

"The world, the sceptical world, shall know the hell you are preparing
for them." Stanford Beale's voice trembled with passion and his face was
dark with the thought of a crime so monstrous that even the outrageous
treatment of a woman who was more to him than all the world was for the
moment obliterated from his mind in the contemplation of the danger
which threatened humanity.

"You say that the police and even the government of this country will
dismiss my charge as being too fantastic for belief. You shall have the
satisfaction of knowing that you are right. They think I am mad--but I
will convince them! In this tube lies the destruction of all your
fondest dreams, van Heerden. To realize those dreams you have murdered
two men. For these you killed John Millinborn and the man Predeaux. But
you shall not----"

"_Bang!_"

The explosion roared thunderously in the confined space of the vault.
Beale felt the wind of the bullet and turned, pistol upraised.

CHAPTER XXVI

THE SECRET OF THE GREEN RUST

A dishevelled figure stood by the boxes, revolver in hand-