We looked at each other, and the horror of the thing sank deep into our minds. Woorali. What was it? There were many travellers in the room who had been in the Orient, home of poisons, and in South America. Which one had run across the poison?
“Woorali, or curare,” said Craig slowly, “is the well-known poison with which the South American Indians of the upper Orinoco tip their arrows. Its principal ingredient is derived from the Strychnos toxifera tree, which yields also the drug nux vomica.”
A great light dawned on me. I turned quickly to where Vanderdyke was sitting next to Mrs. Ralston, and a little behind her. His stony stare and laboured breathing told me that he had read the purport of Kennedy's actions.
“For God's sake, Craig,” I gasped. “An emetic, quick—Vanderdyke.”
A trace of a smile flitted over Vanderdyke's features, as much as to say that he was beyond our interference.
“Vanderdyke,” said Craig, with what seemed to me a brutal calmness, “then it was you who were the visitor who last saw Laura Wainwright and John Templeton alive. Whether you shot a dart at them I do not know. But you are the murderer.”
Vanderdyke raised his hand as if to assent. It fell back limp, and I noted the ring of the bluest lapis lazuli.
Mrs. Ralston threw herself toward him. “Will you not do something? Is there no antidote? Don't let him die!” she cried.
“You are the murderer,” repeated Kennedy, as if demanding a final answer.
Again the hand moved in confession, and he feebly moved the finger on which shone the ring.