nstant the contents assumed a
dull mahogany colour, and a brownish dust was precipitated to the bottom
of the glass jar.

"Ha! ha!" he cried, clapping his hands, and looking as delighted as a
child with a new toy. "What do you think of that?"

"It seems to be a very delicate test," I remarked.

"Beautiful! beautiful! The old Guiacum test was very clumsy and
uncertain. So is the microscopic examination for blood corpuscles. The
latter is valueless if the stains are a few hours old. Now, this appears
to act as well whether the blood is old or new. Had this test been
invented, there are hundreds of men now walking the earth who would long
ago have paid the penalty of their crimes."

"Indeed!" I murmured.

"Criminal cases are continually hinging upon that one point. A man is
suspected of a crime months perhaps after it has been committed. His
linen or clothes are examined, and brownish stains discovered upon them.
Are they blood stains, or mud stains, or rust stains, or fruit stains,
or what are they? That is a question which has puzzled many an expert,
and why? Because there was no reliable test. Now we have the Sherlock
Holmes' test, and there will no longer be any difficulty."

His eyes fairly glittered as he spoke, and he put his hand over his
heart and bowed as if to some applauding crowd conjured up by his
imagination.

"You are to be congratulated," I remarked, considerably surprised at his
enthusiasm.

"There was the case of Von Bischoff at Frankfort last year. He would
certainly have been hung had this test been in existence. Then there was
Mason of Bradford, and the notorious Muller, and Lefevre of Montpellier,
and Samson of new Orleans. I could name a score of cases in which it
would have been decisive."

"You seem to be a walking calendar of crime," said Stamford with a
laugh. "You might start a paper on those lines. Call it the 'Police News
of the Past.'"

"Very interesting reading it might be made, too," remarked Sherlock
Holmes, sticking a small piece of plaster over the prick on his finger.
"I have to be careful," he continued, turning to me with a smile, "for I
dabble with poisons a good deal." He held out his hand as he spoke, and
I noticed that it was all mottled over with similar pieces of plaster,
and discoloured with strong acids.

"We came here on business," said Stamford, sitting down on a high
three-legged stool, and pushing another one in my direction with
his foot. "My friend here w