He had scarcely got to work when there was a knock at his door. It was a firm knock, but not loud, expressing a quiet determination. Professor Ladue seemed to know that knock. He seemed, almost, as if he had been waiting for it.
"Come!" he cried, with an alacrity which would not have been expected of him.
He pushed back his drawing-board and Sally came in.
"Ah, Miss Ladue!" he cried, with a certain spurious gayety which concealed—something. I don't know what it concealed, and neither did Sally, although she knew well enough that there was something behind it. She feared that it was anxiety behind it, and she feared the cause of that anxiety. "And what," continued the Professor, "can we do for Miss Ladue to-day? Will she have more about this lizard of mine?"
Sally's eyes lighted up and she smiled. "I should like that very much, father, thank you. But I can't, this morning, for I'm taking care of Charlie."
"And is Charlie concealed somewhere about you? Possibly you have him in your pocket?"
Sally giggled. "Charlie's tied to a tree."
"Tied to a tree! Does he submit gracefully?"
"He's an alligator; down by the wall, you know."
"Ah!" exclaimed the professor. "I am illumined. Do you think it is quite for the safety of the passers-by to keep an alligator so close to the road?"