But though I proposed to take a bold course and make a short cut to the heart of this infernal mystery, I realised perfectly that if the cut actually led me there, it would prove an exceedingly dangerous by-way. It was such a gamble that I shrank from summoning my cousin until it had come off, but I wrote out the code telegram we had arranged and put it in my pocket ready for emergencies. Of the doctor's two servants the younger anyhow was absolutely trustworthy I was convinced, and I meant to send her with the wire to the post office while I kept guard over the prisoner. And then, to ensure there being a prisoner, I saw that all the chambers of my revolver were loaded and put it in my coat pocket ready to my hand.
The afternoon dragged on, the wind still blustering round the house and the hail now and then rattling on the windows; but no Dr. Rendall appeared. Tea time arrived and still no sign of him. I gave him half an hour's grace and then had my own tea and returned to the smoking-room. The evening by this time had fallen and the curtains were drawn and the lamps lit.
And then at last I heard him enter the front door. I jumped up and, with a dramatic instinct for taking the centre of the stage, placed myself before the fire, but I heard him run upstairs and it was some minutes before the sound of his descending steps reached me. The moment the door opened I was conscious that one of those peculiar changes I had so often noticed had taken place in the man. He smiled at me, but with a curiously furtive eye, and then he shut the door and came forward.
I wasted no time in preliminaries. Keeping my right hand closed over the revolver in my pocket I held out the pocket book with my left.
"Dr. Rendall," I said, "you have heard that Bolton's pocket book has been found. Here it is. Kindly look at that entry."
The man started perceptibly and stared at me. Speaking in that tone and without my eye glasses I must have made an astonishing contrast to the Thomas Hobhouse he had last seen that morning at breakfast.
He took the pocket book and I watched him closely. I saw his eyebrows rise as he read.
"It is Bolton's last entry in his note book before he was murdered, and it means that O'Brien is either still in this island, or that a confederate of his is playing traitor in his place, and that one of the two has just committed murder. It is quite impossible that you don't know something of this!"