estigations a step further."

He laid the cigar down on the table, and, with the keen, thin-bladed
penknife, neatly divided it lengthwise into two halves.

"_Ecce signum_!" exclaimed Thorndyke, as the two parts fell asunder; and
for a few moments we stood silently regarding the dismembered cheroot.
For, about half an inch from the small end, there appeared a little
circular patch of white, chalky material which, by the even manner in
which it was diffused among the leaf, had evidently been deposited from
a solution.

"Our ingenious friend again, I surmise," said Thorndyke at length,
taking up one of the halves and examining the white patch through his
lens. "A thoughtful soul, Jervis, and original too. I wish his talents
could be applied in some other direction. I shall have to remonstrate
with him if he becomes troublesome." "It is your duty to society,
Thorndyke," I exclaimed passionately, "to have this infernal,
cold-blooded scoundrel arrested instantly. Such a man is a standing
menace to the community. Do you really know who sent this thing?"

"I can form a pretty shrewd guess, which, however, is not quite the same
thing. But, you see, he has not been quite so clever this time, for he
has left one or two traces by which his identity might be ascertained."

"Indeed! What traces has he left?"

"Ah! now there is a nice little problem for us to consider." He settled
himself in his easy chair and proceeded to fill his pipe with the air of
a man who is about to discuss a matter of merely general interest.

"Let us consider what information this ingenious person has given us
about himself. In the first place, he evidently has a strong interest in
my immediate decease. Now, why should he feel so urgent a desire for my
death? Can it be a question of property? Hardly; for I am far from a
rich man, and the provisions of my will are known to me alone. Can it
then be a question of private enmity or revenge? I think not. To the
best of my belief I have no private enemies whatever. There remains only
my vocation as an investigator in the fields of legal and criminal
research. His interest in my death must, therefore, be connected with my
professional activities. Now, I am at present conducting an exhumation
which may lead to a charge of murder; but if I were to die to-night the
inquiry would be carried out with equal efficiency by Professor Spicer
or some other toxicologist. My death would not affect the prospects of
the a