with the facts."

"If you will go over in your mind all the points proved to have been
discovered--not the added points in the Record story--I think you
will agree with me that mine is a more logical interpretation than
spontaneous combustion," reasoned Craig. "Hear me out and you will see
that the facts are more in harmony with my less fanciful explanation.
No, someone struck Lewis Langley down either in passion or in cold
blood, and then, seeing what he had done, made a desperate effort to
destroy the evidence of violence. Consider my next discovery."

Kennedy placed the five glasses which I had carefully sealed and
labelled on the table before us.

"The next step," he said, "was to find out whether any articles of
clothing in the house showed marks that might be suspected of being
blood-spots. And here I must beg the pardon of all in the room for
intruding in their private wardrobes. But in this crisis it was
absolutely necessary, and under such circumstances I never let ceremony
stand before justice.

"In these five glasses on the table I have the washings of spots from
the clothing worn by Tom, Mr. James Langley, Junior, Harrington Brown,
and Doctor Putnam. I am not going to tell you which is which--indeed I
merely have them marked, and I do not know them myself. But Mr. Jameson
has the marks with the names opposite on a piece of paper in his pocket.
I am simply going to proceed with the tests to see if any of the stains
on the coats were of blood."

Just then Doctor Putnam interposed. "One question, Professor Kennedy.
It is a comparatively easy thing to recognise a blood-stain, but it is
difficult, usually impossible, to tell whether the blood is that of a
man or of an animal. I recall that we were all in our hunting-jackets
that day, had been all day. Now, in the morning there had been an
operation on one of the horses at the stable, and I assisted the
veterinary from town. I may have got a spot or two of blood on my coat
from that operation. Do I understand that this test would show that?"

"No," replied Craig, "this test would not show that. Other tests would,
but not this. But if the spot of human blood were less than the size of
a pin-head, it would show--it would show if the spot contained even
so little as one twenty-thousandth of a gram of albumin. Blood from a
horse, a deer, a sheep, a pig, a dog, could be obtained, but when the
test was applied the liquid in which they were diluted would remain
c