The developer was evidently a very slow one.  For fully half a minute no change could be seen in the uniform surface.  Then, gradually, almost insensibly, the marginal portion began to darken, leaving the outline of the mummy in pale relief.  The change, once started, proceeded apace.  Darker and darker grew the margin of the paper until from slaty grey it had turned to black; and still the shape of the mummy, now in strong relief, remained an elongated patch of bald white.  But not for long.  Presently the white shape began to be tinged with grey, and, as the colour deepened, there grew out of it a paler form that seemed to steal out of the enshrouding grey like an apparition, spectral, awesome, mysterious.  The skeleton was coming into view.

“It is rather uncanny,” said Dr. Norbury.  “I feel as if I were assisting at some unholy rite.  Just look at it now!”

The grey shadow of the cartonnage, the wrappings and the flesh was fading away into the black background and the white skeleton stood out in sharp contrast.  And it certainly was a rather weird spectacle.

“You’ll lose the bones if you develop much farther,” said Dr. Norbury.

“I must let the bones darken,” Thorndyke replied, “in case there are any metallic objects.  I have three more papers in the envelope.”

The white shape of the skeleton now began to grey over and, as Dr. Norbury had said, its distinctness became less and yet less.  Thorndyke leaned over the tray with his eyes fixed on a point in the middle of the breast and we all watched him in silence.  Suddenly he rose.  “Now, Polton,” he said sharply; “get the hypo on as quickly as you can.”

Polton, who had been waiting with his hand on the stop-cock of the drain-tube, rapidly ran off the developer into the bucket and flooded the paper with the fixing solution.

“Now we can look at it at our leisure,” said Thorndyke.  After waiting a few seconds, he switched on one of the glow-lamps, and as the flood of light fell on the photograph, he added:  “You see we haven’t quite lost the skeleton.”

“No.”  Dr. Norbury put on a pair of spectacles and bent down over the tray; and at this moment I felt Ruth’s hand touch my arm, lightly, at first, and then with a strong, nervous grasp; and I could feel that her hand was trembling.  I looked round at her anxiously and saw that she had turned deathly pale.

“Would you rather go out into the gallery?” I asked; for the room with its tightly shut windows was close and hot.

“No,” she replied quietly, “I will stay here.  I am quite well.”  But still she kept hold of my arm.

Thorndyke glanced at her keenly and then looked away as Dr. Norbury turned to him to ask a question.

“Why is it, think you, that some of the teeth show so much whiter than others?”

“I think the whiteness of the shadows is due to the presence of metal,” Thorndyke replied.

“Do you mean that the teeth have metal fillings?” asked Dr. Norbury.