"They gave you a very light dose of chloroform, Miss Wardour."
"Very light," she replies; "and that was most fortunate for me."
"How fortunate?"
"Allow me to explain," interrupts Doctor Heath. "Miss Wardour possesses one of those peculiar constitutions upon which all opiates act with disastrous effect. It is fortunate that a cautious hand,—I was about to say a skilled hand,—administered the drug. I could swear that not the half of an ordinary dose was given her, for a full dose would have prostrated her for days; and the quantity it would require to make you or me sleep soundly for half the night, would kill her outright."
"Ah!" says the detective, softly, to himself. "Ah-h-h!"
"Now I wonder;" it is Mrs. Aliston who speaks. "I wonder how in the world you knew that they had given my niece only a small dose."
"Very easily, madame. The phial is very small, and it is now over two-thirds full."
"That, indeed!" murmurs Mrs. Aliston, feeling somehow extinguished, while the others smile at his simple explanation.
"And now," says the detective, "for my deductions. First, then, the robbers did not enter these grounds last night for the first time. They did not enter the library at random, or because that window could be easily forced. They, whoever they were, knew their grounds, not only from without, but from within. The disturbance in the library is only a ruse,—the robbers wanted nothing, knew they should find nothing, there. They were not amateurs; yet, somehow, in this case, they bungled somewhat in their work. Before they approached this house, every thing was planned, and all was done as planned. They were systematic, therefore successful; and yet—they bungled. They came by the river,—came in a boat, with oars muffled; they came by the footpath over the river slope, and entered your garden by leaping the fence just below the gate, which was locked. Then they followed the footpaths through the shrubbery, and straight to that library window. They came there because they knew it to be the library window, and they wished to cross the library because they knew that from the door of that room they stepped at once upon the stairs, thus having the nearest, easiest and safest route to Miss Wardour's rooms. Either they found her door unlocked, or they were prepared with skeleton keys. Was the door locked, Miss Wardour?"
"It was locked."