but we've only their word for it, you know."
"Not so," replied Thorndyke. "We have excellent corroborative evidence. You noticed that I had cut a small piece out of the blood-stained portion of the handkerchief?"
"Yes; and I was sorry you had done it. Our people won't like that."
"Well, here it is, and we will ask Dr. Jervis to give us his opinion of it."
From the drawer in which the handkerchief had been hidden he brought forth a microscope slide, and setting the microscope on the table, laid the slide on the stage.
"Now, Jervis," he said, "tell us what you see there."
I examined the edge of the little square of fabric (which had been mounted in a fluid reagent) with a high-power objective, and was, for a time, a little puzzled by the appearance of the blood that adhered to it.
"It looks like bird's blood," I said presently, with some hesitation, "but yet I can make out no nuclei." I looked again, and then, suddenly, "By Jove!" I exclaimed, "I have it; of course! It's the blood of a camel!"
"Is that so, doctor?" demanded the detective, leaning forward in his excitement.
"That is so," replied Thorndyke. "I discovered
