y to make a fight to quit that stuff?"

"So help me as long as I live--"

"Don't tell me that. I want you to think it over a while. I 'm going
to have some one stay here with you until I get back this afternoon.
Will you remain quiet?"

"Yes."

"And remember that even if by chance you did n't do much harm, still
you struck. You struck a woman; you struck your sister."

Arsdale cringed. Each word was a harder blow than he, even in his
madness, could strike.

"It's a--terrible thing to remember. But--but it will be always with
me. It will never leave me."

As soon as the detective arrived Donaldson gave him his instructions,
adding,

"Look out for tricks, and be ready to tell me all he says to you."

"I 've had 'em before," answered the man.

CHAPTER XVII

_An Interlude_

She was waiting for him in the library with an expression both eager
and worried. She crossed the room to meet him, but paused half-way as
though really fearful of some change. But she saw only the same kind,
tense face, looking perhaps a bit heavy from weariness, the same dark
eyes with their strange fires, the same slight droop of the shoulders.
There was certainly nothing to fear in him as he stood before her with
a tender, quizzical smile about his large mouth. He looked to her now
more like a big boy than the cold, stern man she had half expected.

"Are you afraid?" he asked.

"No, not standing here where I can see you. But over the telephone
with your strange voice and your half meanings--what _did_ you mean?"

"Nothing you need worry about."

She became suddenly serious.

"I want to tell you now that there is no need of your trying to hide
anything at all from me about Ben."

"I am hiding nothing. But," he asked with quick intuition, "are _you_?"

She hesitated, met his eyes, and dropped her voice.

"I can tell you nothing--not even you--unless you have learned it."

"I, in my turn, don't know what you mean," he answered. "I have
learned nothing new about him. And it is too fair a morning," he
concluded abruptly, "to bother over puzzles. Things have happened so
rapidly that we are probably both muddled, and if we could spend the
time in explanations we should doubtless find that neither of us means
anything."

She was clearly relieved, but it raised a new question in Donaldson's
mind. Of course she understood nothing of what had taken place last
night unless by mental telepathy. But in these days