The Prince shook his head.

“Such things are not the custom with us,” he said.  “They are my servants.  The duty of their life is service.  London is a world unknown to them—­London and all these Western cities.  They have no desire to be made mock of in your streets.  Their life is given to my interests.  They do not need distractions.”

Inspector Jacks was dumfounded.  Such a state of affairs seemed to him impossible.

“Do you mean that they do not take exercise,” he asked, “that they never breathe the fresh air?”

The Prince smiled.

“Such fresh air as your city can afford them,” he said, “is to be found in the garden there, into which I never penetrate and which is for their use.  I see that you look amazed, Mr. Inspector Jacks.  This thing which I have told you seems strange, no doubt, but you must not confuse the servants of my country with the servants of yours.  I make no comment upon the latter.  You know quite well what they are; so do I. With us, service is a religion,—­service to country and service to master.  These men who perform the duties of my household would give their lives for me as cheerfully as they would for their country, should the occasion arise.”

“But their health?” the Inspector protested.  “It is not, surely, well for them to be herded together like this?”

The Prince smiled.

“I am not what is called a sportsman in this country, Mr. Inspector Jacks,” he said, “but you shall go to the house of any nobleman you choose, and if you will bring me an equal number of your valets or footmen or chefs, who can compete with mine in running or jumping or wrestling, then I will give you a prize what you will—­a hundred pounds, or more.  You see, my servants have learned the secret of diet.  They drink nothing save water.  Sickness is unknown to them.”

The Inspector was silent for some time.  Then he rose to his feet.

“Prince,” he said, “what should you declare, then, if I told you that a man of obvious Japanese extraction was seen to enter your house on the morning after the murder, and that he was a person to whom certain circumstances pointed as being concerned in that deed?”

“Mr. Inspector Jacks,” the Prince said calmly, “I was the only person of my race who entered my house that morning.”

The Inspector moved toward the door.

“Your Highness,” he said gravely, “I am exceedingly obliged to you for your courteous attention, and for your kindness after my unfortunate indisposition.”

The Prince smiled graciously.

“Mr. Inspector Jacks,” he said, “your visit has been of great interest to me.  If I can be of any further assistance, pray do not hesitate to call upon me.”

CHAPTER XXIII.  ON THE TRAIL