"In the first place," resumed Kennedy, "I discovered in the air up there in Delaney's room just a trace of cyanogen."
Haynes nodded approvingly, glancing from one to the other of us.
"But," added Craig, as if he had built up a house of cards merely to demolish it, "I don't think that cyanogen was the cause of Delaney's death—although it furnished the clew."
"What could it have been, then?" demanded Haynes, his face clouding.
Kennedy looked at him calmly. "You've heard of anthrax?" he asked simply.
"Y-yes," replied Haynes, meeting his eye fixedly. "Murrain—the cattle disease."
"That is so deadly to human beings sometimes," added Craig. "Well, I've found something very much like anthrax germs in the sweepings that I took up with the vacuum cleaner up there."
Dr. Leslie was listening intently.
"I can't see how it could have been anthrax," he put in, slowly shaking his head. "Why, Kennedy, the symptoms were entirely different."
"No, this was a poisoning of some kind," added Dr. Haynes. "Dr. Leslie himself tells me that you found traces of cyanogen in the air—and you have just said so, too."