“Tell your story,” said the man in plain clothes, addressing the latter.

“I am a coachman, Excellency,” the man answered in a servile tone.  “I have a cab, number eight hundred and seventy-six, at the service of your Excellency, and it was I who drove the gentleman to the hospital yesterday afternoon.”

“What gentleman?”

“The gentleman who was hurt in the house of your Excellency.”

Volterra stared from the cabman to the man in plain clothes, not understanding.  Then it occurred to him that the man in uniform might be wearing it as a disguise, and that he had to do with a party of clever thieves, and he felt for a little revolver which he always carried about with him.

“I know nothing about the matter,” he said.

“Excellency,” continued the cabman, “the poor gentleman was lying here, close to the door, bleeding from his head.  You see the porter has washed the stones this morning.”

“Go on.”  Volterra listened attentively.

“A big man who looked more like a workman than a servant came to call me in the square.  When we got here, he unlocked the door himself, and made me help him to put the gentleman into the cab.  It was about half-past five or a quarter to six, Excellency, and I waited at the hospital door till eight o’clock, but could not get any money.”

“What became of the big man who called you?” asked Volterra.  “Why did he not pay you?”

“He was arrested, Excellency.”

“Arrested?  Why?  For taking a wounded man to the hospital?”

“Yes.  You can imagine that I did not wish to be concerned in other people’s troubles, Excellency, nor to be asked questions.  So when I had seen the man and the doorkeepers take the gentleman in, I drove on about twenty paces, and waited for the man to come out.  But soon two policemen came and went in, and came out again a few minutes later with the big man walking quietly between them, and they went off in the other direction, so that he did not even notice me.”

“What did you do then?”

“May it please your Excellency, I went back to the door and asked the doorkeeper why the man had been arrested, and told him I had not been paid.  But he laughed in my face, and advised me to go to the police for my fare, since the police had taken the man away.  And I asked him many questions but he drove me away with several evil words.”

“Is that all that happened?” asked Volterra.  “Do you know nothing more?”

“Nothing, your Excellency,” whined the man, “and I am a poor father of a family with eight children, and my wife is ill—­”

“Yes,” interrupted Volterra, “I suppose so.  And what do you know about it all?” he enquired, turning to the man in plain clothes.