"It would be if we elected to come. We don't. Moreover, my case is
simplified by circumstances--no one is dependent upon me either
directly or indirectly. I have no relatives--few friends. These, like
you, would call me names for a minute after I 'd gone and then forget."

"You 're talking beautiful nonsense," observed Barstow.

"Schopenhauer says--"

"Damn your barbaric pessimists and all their hungry tribe!"

Donaldson smiled a trifle condescendingly.

"What's the use of talking to you when you 'll not admit a sound
deduction? And yet, if I said you don't know what results when you put
together two known chemicals, you 'd--"

There was a look in Barstow's face that checked Donaldson,--a look of
worried recollection.

"I 'd say nothing," he asserted earnestly, "because I _don't_ always
know."

For a moment his fingers fluttered over the medley of bottles upon the
shelves before him. They paused over a small vial containing a
brilliant scarlet liquid. He picked it out and held it to the light.

"See this?" he asked.

Donaldson nodded indifferently.

"It is a case in point. Theoretically I should have here the innocuous
union of three harmless chemicals; as a matter of fact I had occasion
to experiment with it and learned that I had innocently produced a
vicious and unheard-of poison. The stuff is of no use. It is one of
those things a man occasionally stumbles upon in this work,--better
forgotten. How do I account for it? I don't. Even in science there
is always the unknown element which comes in and plays the devil with
results."

"But according to your no-waste theory, even this discovery ought to
have some use," commented Donaldson with a smile.

"Well," drawled the chemist whimsically, "perhaps it has; it makes
murder very simple for the laity."

"How?"

Barstow turned back to his test-tube, relieved that the conversation
had taken another turn.

"Because of the slowness with which it works. It requires seven days
for the system to assimilate it and yet the stomach stubbornly retains
it all this while. It is impossible to eliminate it from the body once
it is swallowed. It produces no symptoms and leaves no evidence.
There is no antidote. In the end it paralyzes the heart--swiftly,
silently, surely."

Donaldson sat up.

"Any pain?" he inquired.

"None."

Barstow ran his finger over a calendar on the wall. Then he glanced at
his watch.

"Stay a little while longer and