Into the border land of such a neighborhood—­a certain congeries of obscure and labyrinthine streets to the rear of the old Halles—­I accompanied Franz Mueller one wintry afternoon, about an hour before sunset, and perhaps some ten days after our evening in the Rue du Faubourg St. Denis.  We were bound on an expedition of discovery, and the object of our journey was to find the habitat of Guichet the model.

“I am determined to get to the bottom of this Lenoir business,” said Mueller, doggedly; “and if the police won’t help me, I must help myself.”

“You have no case for the police,” I replied.

“So says the chef de bureau; but I am of the opposite opinion.  However, I shall make my case out clearly enough before long.  This Guichet can help me, if he will.  He knows Lenoir, and he knows something against him; that is clear.  You saw how cautious he was the other day.  The difficulty will be to make him speak.”

“I doubt if you will succeed.”

“I don’t, mon cher.  But we shall see.  Then, again, I have another line of evidence open to me.  You remember that orange-colored rosette in the fellow’s button-hole?”

“Certainly I do.”

“Well, now, I happen, by the merest chance, to know what that rosette means.  It is the ribbon of the third order of the Golden Palm of Mozambique—­a Portuguese decoration.  They give it to diplomatic officials, eminent civilians, distinguished foreigners, and the like.  I know a fellow who has it, and who belongs to the Portuguese Legation here. Eh bien! I went to him the other day, and asked him about our said friend—­how he came by it, who he is, where he comes from, and so forth.  My Portuguese repeats the name—­elevates his eyebrows—­in short, has never heard of such a person.  Then he pulls down a big book from a shelf in the secretary’s room—­turns to a page headed ’Golden Palm of Mozambique’—­runs his finger along the list of names—­shakes his head, and informs me that no Lenoir is, or ever has been, received into the order.  What do you say to that, now?”

“It is just what I should have expected; but still it is not a ease for the police.  It concerns the Portuguese minister; and the Portuguese minister is by no means likely to take any trouble about the matter.  But why waste all this time and care?  If I were you, I would let the thing drop.  It is not worth the cost.”

Mueller looked grave.

“I would drop it this moment,” he said, “if—­if it were not for the girl.”

“Who is still less worth the cost,”

“I know it,” he replied, impatiently.  “She has a pretty, sentimental Madonna face; a sweet voice; a gentle manner—­et voila tout.  I’m not the least bit in love with her now.  I might have been.  I might have committed some great folly for her sake; but that danger is past, Dieu merci! I couldn’t love a girl I couldn’t trust, and that girl is a flirt.  A flirt of the worst sort, too—­demure, serious, conventional.  No, no; my fancy for the fair Marie has evaporated; but, for all that, I don’t relish the thought of what her fate might be if linked for life to an unscrupulous scoundrel like Lenoir.  I must do what I can, my dear fellow—­I must do what I can.”