"Not disease," returned Karl hastily; finding he was misunderstood. "I meant a real, actual secret. A dangerous secret, involving life or death to the individual concerned, according as others should hold it sacred or betray it."
A longer pause yet. Mr. Moore staring at Karl through the room's twilight.
"You must speak more plainly, Sir Karl, if you wish me to understand." And Karl continued thoughtfully, weighing every word as he spoke it, that it might not harm his brother.
"The case is this, Mr. Moore. I hold in my keeping a dangerous secret. It concerns a--a friend: a gentleman who has managed to put himself in peril of the law. For the present he is evading the law; keeping himself, in fact, concealed alike from enemies and friends, with the exception of one or two who are--I may say--helping to screen him. If there were a necessity for my wishing to confide this secret to you, would you undertake to keep it sacred? Or should you consider it lay in your duty as a conscientious man to betray it?"
"Goodness bless me, no!" cried the doctor. "I'm not going to betray people: it's not in my line. My business is to heal their sickness. You need not fear me. It is a case of debt, I suppose, Sir Karl?"
Karl looked at him for a moment steadily. "And if it were not a case of debt, but of crime, Moore? What then?"
"Just the same. Betraying my fellowmen, whether smarting under the ban of perplexity or of sin, does not rest in my duty, I say. I am not a detective officer. By the way, perhaps that other detective--who turns out to be named Tatton, and to belong to Scotland Yard--may have been down here looking after the very man."
Mr. Moore spoke lightly. Not a suspicion rested upon him that the sad and worn gentleman before him held any solemn or personal interest in this. Karl resumed, his voice insensibly taking a lower tone.
"An individual is lying in concealment, as I have described. His offence was not against you or against me. Therefore, as you observe, and as I judge, it does not lie even in our duty to denounce him. I am helping to screen him. I want you to undertake to do the same when you shall know who he is."
"I'll undertake it with all my heart, Sir Karl. You have some motive for confiding the matter to me."