from
the street." Average examined the walls with attention and returned to
the big keyhole, through which he peeped.

"Do you ever chew gum?" he asked suddenly.

The Chemist stared at him. "It isn't a habit of mine to," he said.

"But you wouldn't have any objection to my sending for some, in
satisfaction of a sudden irresistible craving?"

"Any particular brand? I'll phone the corner drug store."

"Any sort will suit, thank you."

When the gum arrived, Average Jones, after politely offering some to
his host, chewed up a single stick thoroughly. This he rolled out to
an extremely tenuous consistency and spread it deftly across the unused
keyhole, which it completely though thinly, veiled.

"Now, what's that for?" inquired the chemist, eying the improvised
closure with some contempt.

"Don't know, exactly, yet," replied the deviser, cheerfully. "But when
queer and fatal things happen in a room and there's only one opening,
it's just as well to keep your eye on that, no matter how small it is.
Better still, perhaps, if you'd shift your office."

The fat young chemist pushed his hair back, looked out of the window,
and then turned to Average Jones. The rather flabby lines of his face
had abruptly hardened over the firm contour below.

"No. I'm hanged if I will," he said simply.

An amiable grin overspread Average Jones' face.

"You've got more nerve than prudence," he observed. "But I don't say you
aren't right. Since you're going to stick to the ship, keep your eye on
that gum. If it lets go its hold, wire me."

"All right," agreed young Mr. Dorr. "Whatever your little game is, I'll
play it. Give me your address in case you leave town."

"As I may do. I am going to hire a press-clipping bureau on special
order to dig through the files of the local and neighboring city
newspapers for recent items concerning dog-poisoning cases. If our
unknown has devised a new method of canicide, it's quite possible he may
have worked it somewhere else, too. Good-by, and if you can't be wise,
be careful."

Dog-poisoning seemed to Average Jones to have become a popular pastime
in and around New York, judging from the succession of news items which
poured in upon him from the clipping bureau. Several days were exhausted
by false clues. Then one morning there arrived, among other data, an
article from the Bridgeport Morning Delineator which caused the Ad-Visor
to sit up with a jerk. It detailed the poisoning of several dogs