"If properly treated, with a knowledge of his past ailment--no," answered Dr. Schofield; "but if he were treated just like an ordinary madman in a pauper lunatic asylum, he would probably never recover. He would become worse and worse and finally be incurable. I see two objections to accepting any theory of this sort as accounting for his disappearance," the doctor continued, after a short pause. "In the first place the shock would have to be violent and unexpected, and this seems improbable; in the next place, he would surely have had some letter or something about him which would have led to his identification!" "If the shock were the result of foul play, these would be destroyed," I suggested. "Undoubtedly; but whence the foul play? Hart is known to have had only a few pounds with him when he left." "Perhaps he had something in his keeping more valuable than money," I remarked. "What?" "A secret." "Have you any grounds for such a belief?" the doctor asked curiously. I hesitated. In my own mind I believed that I had; but for the present, at any rate, this was best kept to myself. I answered quite truthfully, however. "I have made a few inquiries here and there," I said, "and I have heard it hinted that he had some secret means of replenishing his purse. He has been known more than once to leave here with only a few sovereigns in his pocket and to come back with his sovereigns turned into banknotes." "I remember hearing some such tale," the doctor remarked. "I'm afraid it is all rather vague, though." "I'm very much obliged to you, Dr. Schofield," I assured him, rising to take my leave. He followed me to the door and then returned to his interrupted dinner. I mounted into the dog cart and we were soon bowling through the darkness towards Borden Tower. "Get anything out of the old chap?" Cecil asked. "Not much. I'm just a little wiser than I was before, that's all. Beastly sorry to keep you waiting so long!" "Oh, that's all right! But I say, Phil," he added, "what is this idea of yours? You can tell me, can't you?" "If it comes to anything, I will," I assured him. "But at present it is altogether too vague and you would only laugh at it. Don't ask me anything more about it yet, there's a good fellow." "You're very close, all of a sudden," he grumbled. "Why can't you tell me?" "Because I'm afraid of your letting it out to someone whom I don't want to know anything about it," I answered. He laughed. "Ah, well, perhaps you're right!" he said. "I couldn't keep anything back from Milly." I echoed his laugh, but held my peace. It was not Milly alone from whom I wished my present idea to be kept a secret. In fact, I had not thought of Milly at all. I was only anxious that de Cartienne should remain altogether in the dark as to my clue; and for a remarkably good reason. CHAPTER XXXV. AN INVITATION.