David took up the cup and walked to the window. About a tablespoonful of cold tea remained. David tilted the cup, then became suddenly attentive. That small remainder of cold tea with the little skim of cream upon it had suddenly become of absorbing interest. David tilted the cup still more. The tea made a little pool on one side of it, and all across the bottom of the cup a thick white sediment drained slowly down into the pool. It was such a sediment as is left by very chalky water. But all the water of Market Harford is as soft as rain-water. It is not only chalk that makes a sediment like that. Arsenic makes one, too. David put down the cup quickly. He opened the door and went out into the passage. From the far end Elizabeth Chantrey came to meet him, and he gave her a hastily scribbled note for the chemist, and asked her for one or two things that were in the house. When he came back into Mr. Mottisfont’s room he went straight to the wash-stand, took up a small glass bottle labelled ipecacuanha wine and spent two or three minutes in washing it thoroughly. Then he poured into it very carefully the contents of the cup. He did all this in total silence, and in a very quiet and business-like manner. Old Mr. Edward Mottisfont lay on his right side and watched him. His face was twisted with pain, and there was a dampness upon his brow, but his eyes followed every motion that David made and noted every look upon his face. They were intent—alive—observant. Whilst David stood by the wash-stand, with his back towards the bed, old Mr. Edward Mottisfont’s lips twisted themselves into an odd smile. A gleam of sardonic humour danced for a moment in the watching eyes. When David put down the bottle and came over to the bed, the gleam was gone, and there was only pain—great pain—in the old, restless face. There was a knock at the door, and Elizabeth Chantrey came in. Three hours later David Blake came out of the room that faced old Mr. Mottisfont’s at the farther end of the corridor. It was a long, low room, fitted up as a laboratory—very well and fully fitted up—for the old man had for years found his greatest pleasure and relaxation in experimenting with chemicals. Some of his experiments he confided to David, but the majority he kept carefully to himself. They were of a somewhat curious nature. David Blake came out of the laboratory with a very stern look upon his face. As he went down the stair he met with Edward Mottisfont coming up. The sternness intensified. Edward looked an unspoken question, and then without a word turned and went down before David into the hall. Then he waited. “Gone?” he said in a sort of whisper, and David bent his head.