The wine was soon forthcoming and then a cigar for the detective and a pipe for the doctor. At last the latter threw himself into an old easy chair and gazed at his caller expectantly.
"I am ready to untie the knot," he said. "What is it?"
"Briefly put, doctor, the case is this," said Adam Adams. "I want to know if there is anything known to the medical world, a powder or something of that sort, strong enough to kill a person if he should breathe of it."
"A powder strong enough to kill a person?" The brow of the old physician contracted. "It would have to be very powerful to do that. You mean if a person was boxed up with it--like one killed by gas?"
"No, not at all. I mean a powder that could be held to a person's nose and mouth in the open, when it would make that person sick and give him cramps perhaps."
The old doctor rubbed his hands in thought. "That is a subject for speculation. Certain cyanide compounds might be powerful enough to do so under certain conditions. Any real dry powder would choke a person if he got a big dose of it. I heard of a boy who came near dying as the result of breathing in a quantity of extra dry licorice powder. But he was smothered and did not have cramps."
"Nothing in the shape of any foreign compound? You once showed me a Turkish liquid that burnt when water was poured on it, and dyed everything blood red."
"Ah, yes, the _fozeska_, something truly dangerous. But I know of nothing-- But hold!" The doctor clapped his hands together. "Yes! yes! That would do it, that and that only."
"I had a sample of it given to me some six months ago. It was called _yamlang-peholo_, and was made in China, from the roots of the _yamlang_ bush--a rare growth found only in the western part of the country. By many Chinamen the _yamlang_ bush is supposed to be accursed, and whenever they come near one they utter a prayer for deliverance from its evils. If you sleep near the _yamlang_ bush it will make you very sick."
"And that powder, what did it look like?"
"It was blue at first but on contact with the air quickly changed to brownish-white and lost itself, it was so fine."
"You can call it that if you wish. It was intense. I held it at arms' length, yet it made me sick and I had cramps for over an hour afterwards."