I well remember his coming in to see me on the evening of the 4th of August, 1914. “So the war has broken out,” he said, “and the streets are impassable with excited crowds. Odd, isn’t it? Just as if each of us already was not a far more murderous battlefield than any which can be conceived between warring nations.” “How’s that?” said I. “Let me try to put it plainly, though it isn’t that I want to talk about. Your blood is one eternal battlefield. It is full of armies eternally marching and counter-marching. As long as the armies friendly to you are in a superior position, you remain in good health; if a detachment of microbes that, if suffered to establish themselves, would give you a cold in the head, entrench themselves in your mucous membrane, the commander-in-chief sends a regiment down and drives them out. He doesn’t give his orders from your brain, mind you--those aren’t his headquarters, for your brain knows nothing about the landing of the enemy till they have made good their position and given you a cold.” He paused a moment. “There isn’t one headquarters inside you,” he said, “there are many. For instance, I killed a frog this morning; at least most people would say I killed it. But had I killed it, though its head lay in one place and its severed body in another? Not a bit: I had only killed a piece of it. For I opened the body afterwards and took out the heart, which I put in a sterilised chamber of suitable temperature, so that it wouldn’t get cold or be infected by any microbe. That was about twelve o’clock to-day. And when I came out just now, the heart was beating still. It was alive, in fact. That’s full of suggestions, you know. Come and see it.” The Terrace had been stirred into volcanic activity by the news of war: the vendor of some late edition had penetrated into its quietude, and there were half a dozen parlour-maids fluttering about like black and white moths. But once inside Horton’s door isolation as of an Arctic night seemed to close round me. He had forgotten his latch-key, but his housekeeper, then newly come to him, who became so regular and familiar a figure in the Terrace, must have heard his step, for before he rang the bell she had opened the door, and stood with his forgotten latch-key in her hand. “Thanks, Mrs. Gabriel,” said he, and without a sound the door shut behind us. Both her name and face, as reproduced in some illustrated daily paper, seemed familiar, rather terribly familiar, but before I had time to grope for the association, Horton supplied it.