hotel. We can work out the details right now. All I am asking of you is to find out, when the rats come, why they come and, once we know that, we can do something to solve this problem."

"The game looks interesting," declared the Professor of rat psychology. "What I am interested in is why the rats do it. I am sure that it is because they want to do it, but are they forced to want to do it? It is a problem that will take a lot of research to solve, but Rastell and I can solve it. With all respects to our friend, Mr. Crawford, I think that he had better stay away and just keep on reading about his little pets. A few thousand vicious rats would be hard for him to deal with."

"I guess you are right," laughed Winifred Willowby. "Crawford and I will stay here and read about it while you two do the actual scientific work. By the way, Crawford, in that story of the Piper, what was given the credit for drawing the rats out of the town?"

"The tune that he played on the pipes!"

"Check and double check. Now I would advise you gentlemen to locate some musical instrument in that warehouse, and if you find one, experiment with it. Of course, you will have to be rather clever to find it. In the first place, the people putting it there will have it under cover and just as soon as the mischief is done they will remove it."

"It is nothing like that," laughed Professor Wilson, almost in scorn. "These are New York rats. It will take more than a little music to lead them from their usual haunts. But Rastell and I will start in at once. Give us the address of the buildings and the authority to use them. How shall we know when the rats are going to come?"

"They will appear within seven days after you stop the racket money. Suppose we adjourn the meeting? I want a few words in private with Mr. Crawford. You other gentlemen can get all the rest of the details from my secretary. He will arrange your salary and expense account. Good night."

He took Mr. Crawford into his bedroom.

"Do you really believe that story, Crawford?"

"I positively do. And the people believe it. The Piper walked down the Bungen-Strasse and to this day no music is ever played in that street. They even date time in that town from the day the children disappeared."

"Then, there must be something in it. Suppose we go over to Europe and find out something about that tune, the tune that drew the rats out of Hamelin?"

Rastell and Wilson followed out their programme. They went to the grocery warehouse and made a rat survey. There were a few rodents there but not many. Then they issued orders that the weekly payment of five thousand dollars be stopped. After that they spent their nights in the warehouse. On the fifth night the rats came by the thousands. They appeared to be hunting for something, but in the meantime, they ate and soiled whatever came their way. The local cats fought heroically, but were soon killed and eaten. The rats came up from the cellar through the elevator shafts, up the steps, through the cracks in the floor, up and up till they started to run around the roof. Then, at four in the morning, they started to leave, running down the steps in close formation, seemingly panic-stricken at their own temerity and anxious only to return to their safe, dark haunts. The two scientists, in their wire observation cage, closed their note book, opened the door of the cage, and started to make a careful search of the building. It revealed nothing but the bones of cats and much spoiled food.

For the next two days they worked carefully through every part of the building, hunting for something to explain the conduct of the rats. They found nothing. All that they were sure of was the fact that the rats had been there, and that they had not come back.

The following week they repeated the experiment in the laundry. The course of events was the same. The payment was refused, then the rats came, devoured and destroyed, stayed a night and left. Nothing was found. They decided to go