When Henry had departed with his exciting news with which to enliven the somewhat sleepy dovecots of Streatham, Cunningham looked at his chief. They were comfortably ensconced in a small room at the Museum, nominally the abode, during hours, of a library assistant.

“Sure you’re right, chief?” he murmured.

“Absolutely.” Shelley could be very resolute when he chose. “The man died of cyanide poisoning. His lips smelled of almonds when we examined him. And he must have had a pretty hefty dose of cyanide to pop off as quickly as that, without regaining consciousness.”

“Accident or suicide?”

“Accident can, I think, be ruled out. Suicide is just possible, of course,” Shelley admitted. “It’s not at all likely, though.”

“Why not?”

“Two reasons,” said Shelley succinctly. “One: because it is not really likely that such a man as Arnell, a respected figure in the academic world, would commit suicide in the full view of the public. After all, I do know a little about these university people. I’ve been among them before. And they are in many ways different from us merely ordinary folk. Anyhow, I think, if Arnell wanted to commit suicide, he would do so in the decent privacy of his own home, so that there was at any rate a possibility that he would be thought to have died in his bed—of heart failure, say. It all comes down to a matter of psychology, really.”

Shelley’s liking for the somewhat high-falutin jargon of the psychologists was well-known at Scotland Yard, and Cunningham, having no desire to listen to a lecture on the comparative merits of Freud, Jung, and Adler, hastened to turn his chief off this track of surmise on to something more likely to be immediately profitable.

“And reason number two?” he asked.

“These,” said Shelley, producing a packet of sweets.

“Sugared almonds,” murmured Cunningham. “Interesting.”

“Very interesting indeed, and very suggestive,” said Shelley.

“Why suggestive?” Cunningham knew that Shelley found this sort of talk valuable. To argue out any case to a sympathetic listener was always helpful.

Shelley smiled at the naive question. “You understand my funny ways, oh my Cunningham,” he said. “I’ve no doubt that you really know about all these things as much as I know myself. But I won’t apologise for pursuing the obvious, as it does make things easier to work them out in words. These almonds are suggestive, because I feel pretty sure that they are the way in which the poison was given.”

Cunningham’s face expressed such a feeling of complete incredulity that Shelley laughed aloud.

“Consider, Cunningham,” he said. “Cyanide has a distinct almond flavour. If some of it were placed inside a sweet of this kind, would the recipient of it know that fact?”

“Well,” said Cunningham thoughtfully. “I wouldn’t say that it wouldn’t be tasted.”