Hetty fastened the door carefully. Now that she was alone she was feeling more horribly nervous than ever. She locked most of the downstairs doors, and it was only sheer self-contempt that prevented her from fastening her bedroom door. It required a deal of courage to sleep in a large, empty house.
Mamie had half-dropped asleep, but she opened her eyes again as Hetty entered.
"You have been so long," she said, pitifully, "so very long. And why didn't you come when I heard you standing by the door."
"I wasn't standing by the door," Hetty said, quietly.
"But indeed you were. I called out and you said 'Hush' very quietly. Then I heard the rustle of your dress as you went down the stairs."
Hetty murmured something to the effect that she had forgotten. There was no reason to contradict and argue over a child's fancies. Mamie murmured again.
"Take the drops first," Hetty suggested.
Mamie declined fretfully. She wanted water, and that on the table was quite warm. With a patient smile Hetty went downstairs to get more. Mamie drank thirstily. Hetty picked up the little bottle to pour out the drops.
By sheer habit she looked at the label. It was the same, and not the same. Hetty stifled a cry of surprise. She had made no mistake before--of that she was certain. Then what could possibly have happened? Somebody had crept into the room in her absence and changed the bottles!
There could be no doubt about that. The label had the same chemist's name on it, with the red caution of "Poison" underneath. The girl put the bottle to her nostrils and noticed the difference in the smell.