I drove back to the Heron, and in the afternoon I made inquiries about Morton. I found that a rumor had already been circulated in the town that a great detective had come to the Towers, and there was some excitement as to the reason of his visit. Mr. Giles must surely have mentioned our call, I thought. I also heard that Frisby Morton had left for London by the mid-day train, and I wondered if there was any significance in the fact of his departure coinciding with Quarles's arrival. The professor did not return to the Heron until late. He was tired and hungry, and would neither talk nor listen to me until he had made a square meal. "I found a splendid spot to think in, Wigan," he said, when the three of us were in our sitting-room. "A disused gravel-pit. I shared it with a frog for a time, but he worried me so I took him by the leg and threw him out. I looked for him afterward with the intention of throwing him in again. I could not find him, but as I was turning away, would you believe it, he hopped in again of his own accord." I was not in the mood for an AEsop fable, and with some impatience I told him the results of my inquiries that afternoon. "Gone, has he? Business called him to town, I presume?" "Perhaps his solicitor wanted him to be out of reach of questions," I suggested. "Our friend Giles is quite capable of it," Quarles returned. "He has not impressed me; but to return to my frog. There were quite a number of places near that gravel-pit which would have suited him equally well; but no, he would get back to the pit. I cannot say he gave me an idea, but he helped to confirm one. The mind, be it frog's or man's, is certain to be biased by circumstances and environment. If you watched a frog through a period of time, apart from his actions necessary to life and well-being, you would find him doing certain other things, doing them to-day because he did them yesterday. He acquires a habit. Men do the same. The more curious these actions are, the more eccentric the individual becomes. You remember Zena warned us that we had to do with an eccentric in this affair, and therefore was inclined to believe in the existence of a will." Zena nodded.