Mrs. Perrigo took a corner of her shawl between her fingers and proceeded to fold and pleat it while she thoughtfully fixed her eyes on Blindway’s unmoved countenance, as if to find inspiration there.  And after a time she nodded her head as though memory had stirred within her.

“Which every time I see him,” she said, with an evident quickening of interest, “he had two of them dogs with him what has turned-up noses and twisted tails.”

“Pugs?” suggested the chief.

“No doubt that is their name, sir, but unbeknown to me as I never kept such an animal,” answered Mrs. Perrigo.  “My meaning being clear, no doubt, and there being no mistaking of ’em—­their tails and noses being of that order.  And had ’em always on a chain—­gentlemen’s dogs you could see they was, and carefully looked after with blue bows at the back of their necks, same as if they was Christians.  And him, I should say, speaking from memory, a dark young man—­such is my recollection.”

“It comes to this,” remarked the chief, looking at the three listeners with a smile.  “Mrs. Perrigo says that she is certain that upon three occasions about the middle of March last she witnessed meetings at a particular spot in Kensington Gardens between a young woman answering the description and photographs of Lisette Beaurepaire and a young man of whom she cannot definitely remember anything except that she thinks he was dark, spoke a foreign language, and was in charge of two pug dogs which wore blue ribbons.  That’s it, isn’t it, Mrs. Perrigo?”

“And willing to take my solemn oath of the same whenever convenient, sir,” replied Mrs. Perrigo.  “And if so be as what I’ve told you should lead to anything, gentlemen—­and lady—­I can assure you that me being a poor widow, and—­”

Five minutes later, Mrs. Perrigo, with some present reward in her pocket, was walking quietly up Whitehall with a composed countenance, while Allerdyke, already late for his Gresham Street appointment, sped towards the City as fast as a hastily chartered taxi-cab could carry him.  And all the way thither, being alone, he repeated certain words over and over again.

“A dark young man who led two pugs—­a dark young man who led two pugs!  With blue ribbons on their necks—­with blue ribbons on their necks, same as Christians!”

CHAPTER XXII

THICK FOG

It was half-past eleven when Allerdyke reached Gresham Street:  by half-past one, so curiously and rapidly did events crowd upon each other, he was in a state of complete mental confusion.  He sat down to lunch that day feeling as a man feels who has lost his way in an unknown country in the midst of a blinding mist; as a weaver might feel who is at work on an intricate pattern and suddenly finds all his threads inextricably mixed up and tangled.  Instead of things getting better and clearer, that morning’s work made them more hopelessly muddled.