She was a striking-looking woman, dark of hair and skin, and in life she must have been sensuously attractive.  But now her face was drawn and contorted—­with the same ghastly look that had been on the face of Northrop.

“She died in a cab,” explained Doctor Leslie, “before they could get her to the hospital.  At first they suspected the cab driver.  But he seems to have proved his innocence.  He picked her up last night on Fifth Avenue, reeling—­thought she was intoxicated.  And, in fact, he seems to have been right.  Our tests have shown a great deal of alcohol present, but nothing like enough to have had such a serious effect.”

“She told nothing of herself?” asked Kennedy.

“No; she was pretty far gone when the cabby answered her signal.  All he could get out of her was a word that sounded like ’Curio-curio.’  He says she seemed to complain of something about her mouth and head.  Her face was drawn and shrunken; her hands were cold and clammy, and then convulsions came on.  He called an ambulance, but she was past saving when it arrived.  The numbness seemed to have extended over all her body; swallowing was impossible; there was entire loss of her voice as well as sight, and death took place by syncope.”

“Have you any clue to the cause of her death?” asked Craig.

“Well, it might have been some trouble with her heart, I suppose,” remarked Doctor Leslie tentatively.

“Oh, she looks strong that way.  No, hardly anything organic.”

“Well, then I thought she looked like a Mexican,” went on Doctor Leslie.  “It might be some new tropical disease.  I confess I don’t know.  The fact is,” he added, lowering his voice, “I had my own theory about it until a few moments ago.  That was why I called you.”

“What do you mean?” asked Craig, evidently bent on testing his own theory by the other’s ignorance.

Doctor Leslie made no answer immediately, but raised the sheet which covered her body and disclosed, in the fleshy part of the upper arm, a curious little red swollen mark with a couple of drops of darkened blood.

“I thought at first,” he added, “that we had at last a genuine ‘poisoned needle’ case.  You see, that looked like it.  But I have made all the tests for curare and strychnin without results.”

At the mere suggestion, a procession of hypodermic-needle and white-slavery stories flashed before me.

“But,” objected Kennedy, “clearly this was not a case of kidnaping.  It is a case of murder.  Have you tested for the ordinary poisons?”

Doctor Leslie shook his head.  “There was no poison,” he said, “absolutely none that any of our tests could discover.”

Kennedy bent over and squeezed out a few drops of liquid from the wound on a microscope slide, and covered them.

“You have not identified her yet,” he added, looking up.  “I think you will find, Leslie, that there is a Senora Herreria registered at the Prince Henry who is missing, and that this woman will agree with the description of her.  Anyhow, I wish you would look it up and let me know.”