“I had no definite theory about him,” said Alleyn. “That’s why I talked about a fluke. I was uneasy about him. I had a hunch, and I hate hunches. The first day I saw him in his house I began to feel jumpy about him, and fantastic ideas kept dodging about at the back of my mind. He was, it seemed, a fanatic. That long, hectic harangue about hereditary taints— somehow it was too vehement. He was obviously nervous about the case and yet he couldn’t keep off it. He very delicately urged the suicide theory and backed it up with a lecture on eugenics. He was certainly sincere, too sincere, terribly earnest. The whole atmosphere was unbalanced. I recognised the man with an idèe fixe. Then he told me a long story about how he’d once given an overdose, and that was why he never gave injections. That made me uncomfortable, because it was such a handy proof of innocence. ‘He can’t have done the job, because he never gives an injection.’ Then I saw his stethoscope with rows of notches on the stem, and again there was a perfect explanation. He said it was a sort of tally for every anæsthetic he gave successfully to patients with heart disease. I was reminded of Indian tomahawks and Edward S. Ellis, and more particularly of a catapult I had as a boy and the notches I cut in the handle for every bird I killed. The fantastic notion that the stethoscope was that sort of tally-stick nagged and nagged at me. When we found he was one of the Lenin Hall lot I wondered if he could possibly be their agent, and yet I didn’t somehow think there was anything in the Lenin Hall lot. When we discovered he had hoped to egg them on over the Sterilization Bill I felt that accounted perfectly for his association with them. Next time I saw him I meant to surprise him with a sudden question about them. He completely defeated me by talking about them of his own accord. That might have been a subtle move, but I didn’t think so. He lent me his book and here again I found the fanatic. I don’t know why it is that pursuit of any branch of scientific thought which is greatly concerned with sex so often leads to morbid obsession. Not always, by any means—but very often. I’ve met it over and over again. It’s an interesting point and I’d like to know the explanation. Roberts’s book is a sound, a well-written plea for rational breeding. It is not in the least hysterical, and yet, behind it, in the personality of the writer, I smelt hysteria. There was one chapter where he said that a future civilization might avoid the expense and trouble of supporting its a-ments and de-ments, by eliminating them altogether. ‘Sterilization,’ he wrote, ‘might in time be replaced by extermination.’ After reading that I forced myself to face up to that uneasy idea that had worried me ever since I first spoke to him. O’Callaghan came of what Roberts would regard as tainted stock. Suppose—suppose, thought I, blushing at my own credulity, suppose Roberts had got the bright idea of starting the good work by destroying such people every time he got the opportunity? Suppose he had brought it off several times before, and that every time he’d had a success he ticked it up on his stethoscope?”