“Can’t you guess?  That’s what I meant when I said they had to kill Frank Law.”  Ellsworth maintained his fixity of gaze, and when Dave started he nodded his head.  “It’s God’s truth.  The details were too—­dreadful.  Your father turned his hand against the woman he loved and—­died a wife-killer.  The Guadalupes had to destroy him like a mad dog.  I’m sorry you had to learn the truth from me, my boy, but it seems necessary that I tell you.  When I knew Frank Law he was like any other man, quick-tempered, a little too violent, perhaps, but apparently as sane as you or I, and yet the thing was there.”

Dave rose from his chair and bent over the desk.  “So that’s what you’ve been driving at,” he gasped.  “That’s what you meant when you said I shouldn’t marry.”  He began to tremble now; his voice became hoarse with fury.  “Now I understand.  You’re trying to tell me that—­maybe I’ve got it in me, eh?  Hell!  You’re crazy, not I. I’m all right.  I reckon I know.”

“He didn’t know,” Ellsworth said, quietly.  “I doubt if he even suspected.”

Dave struck the desk violently with his clenched fist.  “Bosh!  You’re hipped on this heredity subject.  Crazy!  Why, you doddering old fool—­” With an effort he calmed himself, realizing that he had shouted his last words.  He turned away and made a circuit of the room before returning to face his friend.  “I didn’t mean to speak to you like that, Judge.  You pulled this on me too suddenly, and I’m—­upset.  But it merely proves my own contention that I’m not Frank Law’s son at all.  I’ve always known it.”

“How do you know it?”

“Don’t you suppose I can tell?” In spite of himself Dave’s voice rose again, but it was plain from the lawyer’s expression that to a man of his training no mere conviction unsupported by proof had weight.  This skepticism merely kept Dave’s impatience at a white heat.  “Very well, then,” he argued, angrily, “let’s say that I’m wrong and you’re right.  Let’s agree that I am his son.  What of it?  What makes you think I’ve inherited—­the damned thing?  It isn’t a disease.  Me, insane?  Rot!” He laughed harshly, took another uncertain turn around the room, then sank into his chair and buried his face in his hands.

Ellsworth was more keenly distressed than his hearer imagined; when next he spoke his voice was unusually gentle.  “It is a disease, Dave, or worse, and there’s no way of proving that you haven’t inherited it.  If there is the remotest possibility that you have—­if you have the least cause to suspect—­why, you couldn’t marry and—­bring children into the world, now could you?  Ask yourself if you’ve shown any signs—?”

“Oh, I know what you mean.  You’ve always said I go crazy when I’m--angry.  Well, that’s true.  But it’s nothing more than a villainous temper.  I’m all right again afterward.”

“I wasn’t thinking so much of that.  But are you sure it’s altogether temper?” the judge insisted.  “You don’t merely lose control of yourself; you’ve told me more than once that you go completely out of your mind; that you see red and want to kill and—­” “Don’t you?”