“I tell you what it is, Sey,” my brother-in-law said, with impressive slowness.  “This time we must deliberately lay ourselves out to be swindled.  We must propose of our own accord to buy the picture, making him guarantee it in writing as a genuine Rembrandt, and taking care to tie him down by most stringent conditions.  But we must seem at the same time to be unsuspicious and innocent as babes; we must swallow whole whatever lies he tells us; pay his price—­nominally—­by cheque for the portrait; and then, arrest him the moment the bargain is complete, with the proofs of his guilt then and there upon him.  Of course, what he’ll try to do will be to vanish into thin air at once, as he did at Nice and Paris; but, this time, we’ll have the police in waiting and everything ready.  We’ll avoid precipitancy, but we’ll avoid delay too.  We must hold our hands off till he’s actually accepted and pocketed the money; and then, we must nab him instantly, and walk him off to the local Bow Street.  That’s my plan of campaign.  Meanwhile, we should appear all trustful innocence and confiding guilelessness.”

In pursuance of this well-laid scheme, we called next day on Dr. Polperro at his hotel, and were introduced to his wife, a dainty little woman, in whom we affected not to recognise that arch Madame Picardet or that simple White Heather.  The Doctor talked charmingly (as usual) about art—­what a well-informed rascal he was, to be sure!—­and Sir Charles expressed some interest in the supposed Rembrandt.  Our new friend was delighted; we could see by his well-suppressed eagerness of tone that he knew us at once for probable purchasers.  He would run up to town next day, he said, and bring down the portrait.  And in effect, when Charles and I took our wonted places in the Pullman next morning, on our way up to the half-yearly meeting of Cloetedorp Golcondas, there was our Doctor, leaning back in his arm-chair as if the car belonged to him.  Charles gave me an expressive look.  “Does it in style,” he whispered, “doesn’t he?  Takes it out of my five thousand; or discounts the amount he means to chouse me of with his spurious Rembrandt.”

Arrived in town, we went to work at once.  We set a private detective from Marvillier’s to watch our friend; and from him we learned that the so-called Doctor dropped in for a picture that day at a dealer’s in the West-end (I suppress the name, having a judicious fear of the law of libel ever before my eyes), a dealer who was known to be mixed up before then in several shady or disreputable transactions.  Though, to be sure, my experience has been that picture dealers are—­picture dealers.  Horses rank first in my mind as begetters and producers of unscrupulous agents, but pictures run them a very good second.  Anyhow, we found out that our distinguished art-critic picked up his Rembrandt at this dealer’s shop, and came down with it in his care the same night to Brighton.

In order not to act precipitately, and so ruin our plans, we induced Dr. Polperro (what a cleverly chosen name!) to bring the Rembrandt round to the Métropole for our inspection, and to leave it with us while we got the opinion of an expert from London.