"Hardly likely," said Evan.
"It must have been a native," insisted Arthur anxiously. "No animal would have had the cunning to creep in, kill the poor girl silently, and then creep out again. It must have been one of the blacks."
"Gorilla," said Evan, shaking his head.
Arthur suddenly looked up.
"I've got it! We'll take a photo of the girl's eyes. I saw a cloudy form on the retina. I've got an insect camera in my luggage, and can make sure what it was that frightened her that last moment of her life."
The expression on the girl's face had been one of terrible fear. Whatever it was that had killed her, she had seen it before she died—seen and known it for a deadly and horrible thing.
"Try it," I urged. "We can't be sure otherwise. If it was a native, our food is poisoned for a certainty."
Arthur went to his room and presently appeared with the queer camera. It was a long box, and evidently the lens was one of great focal length. It took Arthur a long time to adjust it properly. He proposed to take advantage of the fact that the eye of a dead person will retain for from twenty-four to forty-eight hours the impression of what it saw last while living. A great many people think that the shining image on the outer surface of the eye retains that picture, and wonder at it. As a matter of fact the picture is kept on the retina, in the inside of the eyeball. It is extremely difficult to photograph the retina without dissecting the eye, but it can be done—as Arthur proceeded to prove.
I went outside and searched around the house for possible footprints. After a preliminary search, I got Evan to help me. We could find no single sign of tracks leading toward or away from the house. There had been a heavy dew, and the top layer of the earth was dark and damp. Footprints would inevitably have been shown. When we had completed our search, we stared at each other. Whatever or whoever had killed the native girl must be still in the house. There were absolutely no signs of his having left.
We went inside. Beast or man, something had been in the house, moving quietly and undiscovered despite our watching. It had entered the room occupied by the native girl and had awakened her. She had seen it, and it had been a thing she recognized as frightful. Her horror-stricken face was proof of that. It had been cunning enough to latch the door of the room after the killing. That meant a native. On the other hand, it had broken the girl's neck, a feat that would require incredible strength. That spoke of a monstrous animal. We heard Arthur shuffling about in his improvised dark room, and the clink of the dishes in which he had mixed his solutions.