stains and scars could not hide the beauty of those mobile hands, the hands of an artist and a dreamer. An artist Dr. Bird was, albeit his artistry expressed itself in the most delicate and complicated experiments in the realms of pure and applied science that the world has ever seen, rather than in the commoner forms of art.
The doctor finished his task of weighing a porcelain crucible, set it carefully into a desictator, and turned to his friend.
'What's on your mind, Carnes?" he asked. "You look worried. Is there another counterfeit on the market?"
The operative shook his head.
"Have you been reading those stories that the papers have been carrying about Mammoth Gave?" he asked.
Dr. Bird emitted a snort of disgust.
"I read the first one of them part way through on the strength of its being an Associated Press dispatch," he replied, "but that was enough. It didn't exactly impress me with its veracity, and, from a viewpoint of literature, the thing was impossible. I have no time to pore over the lucubrations of an inspired press agent."
"So you dismissed them as mere press agent work?
"Certainly. What else could they be? Things like that don't happen fortuitously just as the tourist season is about to open. I suppose that those yarns will bring flocks of the curious to Kentucky though: the public always responds well to sea serpent yarns."
"Mammoth Cave has been closed to visitors for the season," said Carnes quietly.
"What?" cried the doctor in surprise. "Was there really something to those wild yarns?"
"THERE was, and what is more to the point, there still is. At least there is enough to it that I am leaving for Kentucky this evening, and I came here for the express purpose of asking you whether you wanted to come along. Bolton suggested that I ask you: he said that the whole thing sounded to him like magic and that magic was more in your line than in ours. He made out a request for your services and I have it in my pocket now. Are you interested?"
"How does the secret service cut in on it?" asked the doctor. "It seems to me that it is a state matter. Mammoth Cave isn't a National Park."
"Apparently you haven't followed the papers. It was a state matter until the Governor asked for federal troops. Whenever the regulars get into trouble, the federal government is rather apt to take a hand."
"I didn't know that regulars had been sent there. Tell me about the case."
"Will you come along?"
Dr. Bird shook his head slowly.
"I really don't see how I can spare the time, Carnes," he said. "I am in the midst of some work of the utmost importance and it hasn't reached the stage where I can turn it over to an assistant."
"Then I won't bother you with the details," replied Carnes as he rose.
"Sit down, confound you!" cried the doctor. "You know better than to try to pull that on me. Tell me your case, and then I'll tell you whether I'll go or not. I can't spare the time, but, on the other hand, if it sounds interesting enough. . . ."
CARNES laughed.
"All right, Doctor," he said, "I'll take enough time to tell you about it even if you can't go. Do you know anything about it?"
"No. I read the first story half way through and then stopped. Start at the beginning and tell me the whole thing."
"Have you ever been to Mammoth Cave?"
"No."
"It, or rather they, for while it is called Mammoth Cave it is really a series of caves, are located in Edmon-
