Freyberger bowed himself out. He had almost four hours to wait before the appointment, and, having nothing particular to do, he determined to make the best use he could of the time at his disposal, and have dinner. He first telephoned to the Yard the result of his interview with Dr Murrell, and then betook himself to a cheap restaurant in Soho, where he proceeded to revel in Sauerkraut and beef, served with stewed plums, slices of sausage and other Teutonic delicacies. Throughout all the varied experiences of his life he had never felt so much excitement as just now, waiting for the result of this sleight of hand photography, this attempt to trick nature out of one of her darkest secrets. It was exactly ten o’clock when he reached the house in Sackville Street, and was admitted. The doctor was not at home, but he had given instructions that the detective should be admitted to his private laboratory, there to await him. It was a large room at the back of the house, built on a space that had once been a yard. It had a top light and something of the general aspect of an artist’s studio. Röntgen ray apparatuses, cameras, all sorts of odds and ends lay about, speaking of the occupant’s bent. Freyberger had not been waiting five minutes when the door opened, and Dr Murrell, in evening dress, entered. He held a small parcel in his hand. “Good evening,” he said. “My assistant was called away half an hour ago, and he left the result of his work for me; let’s see what it is.” He undid the string from the parcel, and disclosed what at first sight appeared to be a large cabinet photograph. He approached an electric light, bearing it in his hand; in the full glare of the light he examined it intently. Then he whistled softly to himself. He seemed quite lost in contemplation of the thing. Freyberger, unable to contain his curiosity, came up behind the doctor and gazed over his shoulder at the photograph, mounted upon the card. It was a large grey-coloured platinotype, showing a blurred and misty picture; it was the picture of a human face. It was the face, the sight of which had killed, from sheer terror, the valet Leloir. The arteries of the dead man’s retina had left their trace upon the photograph, but they did not blur the face; their tracery could be seen in the background, forming a sort of halo round the nebulous visage, that held the two gazers with a witchery all its own. “That is the result,” said the doctor, laying the photograph on a table near by. Freyberger moistened his lips. “Scarcely pretty,” said Dr Murrell, taking a cigarette from a box near by and offering his companion one. “It is a face to give one pause,” said Freyberger, lighting his cigarette in a meditative manner. “I’m sure of this,” said Dr Murrell, leaning back against the mantelpiece and glancing sideways at the thing on the table, “that half of the impression that thing makes upon me is caused by the fact that I have the knowledge of how it was obtained.