"In large-enough doses and repeated often enough," continued Kennedy, "I suppose the toxic effect of the drug might be to produce insanity. At any rate, if we are going to do anything, it might better be done at once. They are all out there now. If we act to-night, surely we shall have the best chance of making the guilty person betray himself."
Kennedy telephoned for a fast touring-car, and in half an hour, while he gathered some apparatus together, the car was before the door. In it he placed a couple of light silk-rope ladders, some common wooden wedges, and an instrument which resembled a surveyor's transit with two conical horns sticking out at the ends.
We made the trip out of New York and up the Boston post-road, following the route which Cranston and Miss Giles must have taken some hours before us. In the town of Montrose, Kennedy stopped only long enough to get a bite to eat and to study up in the roads in the vicinity.
It was long after midnight when we struck up into the country. The night was very dark, thick, and foggy. With the engine running as muffled as possible and the lights dimmed, Kennedy quietly jammed on the brakes as we pulled up along the side of the road.
A few rods farther ahead I could make out the Belleclaire Sanatorium surrounded by its picketed stone wall. Not a light was visible in any of the windows.
"Now that we're here," I whispered, "what can we do?"
"You remember the paper I gave Mrs. Cranston when the excitement in the hall broke loose?"
"Yes," I nodded, as we moved over under the shadow of the wall.
"I wrote on a sheet from my note-book," said Kennedy, "and told her to be ready when she heard a pebble strike the window; and I gave her a piece of string to let down to the ground."
Kennedy threw the silk ladder up until it caught on one of the pickets; then, with the other ladder and the wedges, he reached the top of the wall, followed by me. We pulled the first ladder up as we clung to the pickets, and let it down again inside. Noiselessly we crossed the lawn.