That same day, at three o’clock, Don Luis Perenna, accompanied by Major d’Astrignac, another officer, and a doctor, left the house in the Place du Palais-Bourbon in his car, and, followed by a taxi crammed with the detectives engaged in watching him, drove to the Parc des Princes.

While waiting for the arrival of the adversary, the Comte d’Astrignac took Don Luis aside.

“My dear Perenna, I ask you no questions.  I don’t want to know how much truth there is in all that is being written about you, or what your real name is.  To me, you are Perenna of the Legion, and that is all I care about.  Your past began in Morocco.  As for the future, I know that, whatever happens and however great the temptation, your only aim will be to revenge Cosmo Mornington and protect his heirs.  But there’s one thing that worries me.”

“Speak out, Major.”

“Give me your word that you won’t kill this man.”

“Two months in bed, Major; will that suit you?”

“Too long.  A fortnight.”

“Done.”

The two adversaries took up their positions.  At the second encounter, the editor of the Echo de France fell, wounded in the chest.

“Oh, that’s too bad of you, Perenna!” growled the Comte d’Astrignac.  “You promised me—­”

“And I’ve kept my promise, Major.”

The doctors were examining the injured man.  Presently one of them rose and said: 

“It’s nothing.  Three weeks’ rest, at most.  Only a third of an inch more, and he would have been done for.”

“Yes, but that third of an inch isn’t there,” murmured Perenna.

Still followed by the detectives’ motor cab, Don Luis returned to the Faubourg Saint-Germain; and it was then that an incident occurred which was to puzzle him greatly and throw a most extraordinary light on the article in the Echo de France.

In the courtyard of his house he saw two little puppies which belonged to the coachman and which were generally confined to the stables.  They were playing with a twist of red string which kept catching on to things, to the railings of the steps, to the flower vases.  In the end, the paper round which the string was wound, appeared.  Don Luis happened to pass at that moment.  His eyes noticed marks of writing on the paper, and he mechanically picked it up and unfolded it.

He gave a start.  He had at once recognized the opening lines of the article printed in the Echo de France.  And the whole article was there, written in ink, on ruled paper, with erasures, and with sentences added, struck out, and begun anew.

He called the coachman and asked him: 

“Where does this ball of string come from?”

“The string, sir?  Why, from the harness-room, I think.  It must have been that little she-devil of a Mirza who—­”

“And when did you wind the string round the paper?”

“Yesterday evening, Monsieur.”