"What's that?" asked Bert.
"Sterilized water."
"Say, where did you find that bottle?" demanded Jack.
"In Farmer Appleby's barn," was the calm rejoinder. "I picked it up just by chance, but it may mean something big."
"What?" cried Jack. "You don't mean to say you've been around there?"
"Surely. Why not?"
"Why, he might think you wanted to do away with the rest of his horses."
"He didn't see me. I took care of that. Besides that's the only place where I can consistently look for clews. I was sure whoever poisoned the horses must have left some trace behind him, and this may be it."
"The empty bottle?" asked Bert incredulously.
"It may not be altogether empty," replied Tom. "That's what I'm going to test for. I saw traces of some powder on the sides, and I want to see if my suspicions are true."