“If you are walking in the same direction as I am, Dr. Jervis, we might arrange the time of our proposed visit as we go along.”

I was not slow to avail myself of this invitation, and a few seconds later we left the house together, leaving Mrs. Hornby smiling fatuously after us from the open door.

“Will eight o’clock suit you, do you think?” Miss Gibson asked, as we walked up the street.

“It will do excellently, I should say,” I answered.  “If anything should render the meeting impossible I will send you a telegram.  I could wish that you were coming alone, as ours is to be a business conference.”

Miss Gibson laughed softly—­and a very pleasant and musical laugh it was.

“Yes,” she agreed.  “Dear Mrs. Hornby is a little diffuse and difficult to keep to one subject; but you must be indulgent to her little failings; you would be if you had experienced such kindness and generosity from her as I have.”

“I am sure I should,” I rejoined; “in fact, I am.  After all, a little diffuseness of speech and haziness of ideas are no great faults in a generous and amiable woman of her age.”

Miss Gibson rewarded me for these highly correct sentiments with a little smile of approval, and we walked on for some time in silence.  Presently she turned to me with some suddenness and a very earnest expression, and said—­

“I want to ask you a question, Dr. Jervis, and please forgive me if I beg you to put aside your professional reserve just a little in my favour.  I want you to tell me if you think Dr. Thorndyke has any kind of hope or expectation of being able to save poor Reuben from the dreadful peril that threatens him.”

This was a rather pointed question, and I took some time to consider it before replying.

“I should like,” I replied at length, “to tell you as much as my duty to my colleague will allow me to; but that is so little that it is hardly worth telling.  However, I may say this without breaking any confidence:  Dr. Thorndyke has undertaken the case and is working hard at it, and he would, most assuredly, have done neither the one nor the other if he had considered it a hopeless one.”

“That is a very encouraging view of the matter,” said she, “which, had, however, already occurred to me.  May I ask if anything came of your visit to Scotland Yard?  Oh, please don’t think me encroaching; I am so terribly anxious and troubled.”

“I can tell you very little about the results of our expedition, for I know very little; but I have an idea that Dr. Thorndyke is not dissatisfied with his morning’s work.  He certainly picked up some facts, though I have no idea of their nature, and as soon as we reached home he developed a sudden desire to examine the ‘Thumbograph.’”

“Thank you, Dr. Jervis,” she said gratefully.  “You have cheered me more than I can tell you, and I won’t ask you any more questions.  Are you sure I am not bringing you out of the way?”