where came the little prescription department.
Carefully, so as to arouse no suspicion, she began to bore away at the
wall with various tools, until finally she had a small, almost
imperceptible opening. It was tedious work, and toward the end needed
great care so as not to excite suspicion. But finally she was rewarded.
Through it she could see just a trace of daylight, and by squinting
could see a row of bottles on a shelf opposite.

Then, through the hole, she pushed a long, narrow tube, like a putty
blower. When at last she placed her eye at it, she gave a low
exclamation of satisfaction. She could now see the whole of the little
room.

It was a detectascope, invented by Gaillard Smith, adapter of the
detectaphone, an instrument built up on the principle of the cytoscope
which physicians use to explore internally down the throat. Only, in
the end of the tube, instead of an ordinary lens, was placed what is
known as a "fish-eye" lens, which had a range something like nature has
given the eyes of fishes, hence the name. Ordinarily cameras, because
of the flatness of their lenses, have a range of only a few degrees,
the greatest being scarcely more than ninety. But this lens was
globular, and, like a drop of water, refracted light from all
directions. When placed so that half of it caught the light it "saw"
through an angle of 180 degrees, "saw" everything in the room instead
of just that little row of bottles on the shelf opposite.

Constance set herself to watch, and it was not long before her
suspicions were confirmed, and she was sure that this was nothing more
than a "coke" joint. Still she wondered whether Muller was the real
source of the traffic of which Sleighbells was the messenger. She was
determined to find out.

All day she watched through her detectascope. Once she saw Adele come
in and buy more dope. It was with difficulty that she kept from
interfering. But, she reflected, the time was not ripe. She had thought
the thing out. There was no use in trying to get at it through Adele.
The only way was to stop the whole curse at its source, to dam the
stream. People came and went. She soon found that he was selling them
packets from a box hidden in the woodwork. That much she had learned,
anyhow.

Constance watched faithfully all day with only time enough taken out
for dinner. It was after her return from this brief interval that she
felt her heart give a leap of apprehension, as she looked again throug