use of the sulpho-cyanide, and though he could count on Vera Lytton's
placing the note in the jar of ammonia and hence obliterating the
writing, while at the same time the invisible writing in the mercurous
nitrate involving Dr. Dixon's name would be brought out by the ammonia
indelibly on the other side of the note - he forgot" - Kennedy was
now speaking eagerly and loudly - "that the sulpho-cyanide vapours
could always be made to bring back to accuse him the words that the
ammonia had blotted out."

Before the prosecutor could interfere, Kennedy had picked up the
note found in the ammonia-jar beside the dying girl and had jammed
the state's evidence into the long-necked flask of sulpho-cyanide
vapour.

"Don't fear," he said, trying to pacify the now furious prosecutor,
"it will do nothing to the Dixon writing. That is permanent now,
even if it is only a tracing."

When he withdrew the note, there was writing on both sides, the
black of the original note and something in red on the other side.

We crowded around, and Craig read it with as much interest as any
of us:

"Before taking the headache-powder, be sure to place the contents
of this paper in a jar with a little warm water."

"Hum," commented Craig, "this was apparently on the outside wrapper
of a paper folded about some sal-ammoniac and quicklime. It goes on: