“I got one, Warden!  A beaut!” came Riley’s voice from down the corridor, and he came in with a wire cage containing a large rat which cowered in one corner of his cell, even as Singa Phut had shrunk into his when the end came.

“How you going to get at him, Colonel?” asked the warden.  “They’re nasty to handle.  One of ’em nipped my dog fierce when I gave him a chance at killing it a day or so ago.”

“I’m not going to let it out.  If I had a stick, or something that I could fasten the needle on, I could work a sort of javelin,” remarked the colonel.

“I’ll get you one,” offered Riley, much interested in the coming experiment.  Donovan, too, looked on in startled wonder.

A long, slender stick was brought and, using great care, with his rubber gloves on that he used in autopsies, Doctor Warren fastened the needle to the wand.  Then Colonel Ashley thrust the improvised spear through the wires of the cage and lightly punctured the rat, which gave a protesting squeak.

“It didn’t hurt him much,” observed the colonel, “and, if I have guessed right, his death will be painless.”

“How soon?” asked Donovan.

“I can’t say, but it ought not be very long.  The kind of poison they use is calculated to work swiftly.”

In the glaring light from the nitrogen bulb they stood in the cell of the dead man, gathered about the cage of the rat—­a prison within a prison.  After the first start caused by the needle prick, the rodent again shrank back into its corner.  For perhaps ten minutes it remained thus, and then it began to exhibit signs of uneasiness.  It stood up on its haunches and began to bite at the wires of the cage.  It squeaked, more as though uneasy than in pain,

In another minute it began to run around the tin floor of its prison, and then it suddenly stopped in its tracks, fell over in a lump and was still.

“Well, I’ll be—­” began Donovan, and then, with a look at the colonel, he substituted:  “This gets me!  It sure does!”

“It evidently went right to the heart, just as in Singa Phut’s case,” observed the colonel grimly.

“You were right,” said Doctor Warren, “it was poison.  He probably jabbed himself with the point of the needle, and whatever was smeared on it did the rest.  I shall be interested in making the autopsy.”

“You will probably find very little trace of the poison,” said the colonel.  “The kind they use is designed to disappear almost as soon as it becomes effective.  Still you may discover something.”

But Doctor Warren did not.  Aside from a little scratch near the prisoner’s heart, where he had evidently dug the needle deep into his skin, there was no sign that death was other than by natural causes.  The poison had gone directly into the blood, as does the venom of a snake, and had brought death in the same way.  In fact, it was the opinion of Colonel Ashley that some form of snake poison was used, though what it was, no one could say.