It might have been all right twenty years ago, when most people argued and behaved fairly logically. But they don’t nowadays. Have you ever realised, Dick, the amount of stark craziness that the War has left in the world?”

Mary, who was sitting sewing under a lamp, raised her head and laughed.

Greenslade’s face had become serious. “I can speak about it frankly here, for you two are almost the only completely sane people I know. Well, as a pathologist, I’m fairly staggered. I hardly meet a soul who hasn’t got some slight kink in his brain as a consequence of the last seven years. With most people it’s rather a pleasant kink—they’re less settled in their grooves, and they see the comic side of things quicker, and are readier for adventure. But with some it’s pukka madness, and that means crime. Now, how are you going to write detective stories about that kind of world on the old lines? You can take nothing for granted, as you once could, and your argus-eyed, lightning-brained expert has nothing solid with which to build his foundations.”

I observed that the poor old War seemed to be getting blamed for a good deal that I was taught in my childhood was due to original sin.

“Oh, I’m not questioning your Calvinism. Original sin is always there, but the meaning of civilisation was that we had got it battened down under hatches, whereas now it’s getting its head up. But it isn’t only sin. It’s a dislocation of the mechanism of human reasoning, a general loosening of screws. Oddly enough, in spite of parrot-talk about shell-shock, the men who fought suffer less from it on the whole than other people. The classes that shirked the War are the worst—you see it in Ireland. Every doctor nowadays has got to be a bit of a mental pathologist. As I say, you can hardly take anything for granted, and if you want detective stories that are not childish fantasy you’ll have to invent a new kind. Better try your hand, Dick.”

“Not I. I’m a lover of sober facts.”

“But, hang it, man, the facts are no longer sober. I could tell you—” He paused and I was expecting a yarn, but he changed his mind.

“Take all this chatter about psycho-analysis. There’s nothing very new in the doctrine, but people are beginning to work it out into details, and making considerable asses of themselves in the process. It’s an awful thing when a scientific truth becomes the quarry of the half-baked. But as I say, the fact of the subconscious self is as certain as the existence of lungs and arteries.”

“I don’t believe that Dick has any subconscious self,” said Mary.

“Oh yes, he has. Only, people who have led his kind of life have their ordinary self so well managed and disciplined—their wits so much about them, as the phrase goes—that the subconscious rarely gets a show. But I bet if Dick took to thinking about his soul, which he never does, he would find some queer corners. Take my own case.” He turned towards me so that I had a full view of his candid eyes and hungry cheek-bones which looked prodigious in the firelight. “I belong more or less to the same totem as you, but I’ve long been aware that I possessed a most curious kind of subconsciousness. I’ve a good memory and fair powers of observation, but they’re nothing to those of my subconscious self. Take any daily incident. I see and hear, say, about a twentieth part of the details and remember about a hundredth part—that is, assuming that there is nothing special to stimulate my interest. But my subconscious self sees and hears practically everything, and remembers most of it.