He picked up a bottle of something with a faint greenish tinge.
"See the bands gradually fade?"
I watched, and indeed they did diminish in intensity and finally disappear, leaving an uninterrupted and brilliant spectrum.
"My spectroscope," he said, simply, "shows that the blood-crystals of Barnes are colorless. Barnes was poisoned--by some gas, I think. I wish I had time to hunt along the road where the accident took place." As he said it, he walked over and drew from a cabinet several peculiar arrangements made of gauze.
He was about to say something more when there came a knock at the door. Kennedy shoved the gauze arrangements into his pocket and opened it. It was Maude Euston, breathless and agitated.
"Oh, Mr. Kennedy, have you heard?" she cried. "You asked me to keep a watch whether anything more happened to Mr. Barnes. So I asked some frie