What Lupin felt most in the whole business was Daubrecq's revelation of the whereabouts of the flat. The police had entered his place in the Rue Chateaubriand. The identity of Lupin and Michel Beaumont had been recognized and certain papers discovered; and Lupin, while pursuing his aim, while, at the same time, managing various enterprises on which he had embarked, while avoiding the searches of the police, which were becoming more zealous and persistent than ever, had to set to work and reorganize his affairs throughout on a fresh basis.

His rage with Daubrecq, therefore, increased in proportion to the worry which the deputy caused him. He had but one longing, to pocket him, as he put it, to have him at his bidding by fair means or foul, to extract his secret from him. He dreamt of tortures fit to unloose the tongue of the most silent of men. The boot, the rack, red-hot pincers, nailed planks: no form of suffering, he thought, was more than the enemy deserved; and the end to be attained justified every means.

"Oh," he said to himself, "oh, for a decent bench of inquisitors and a couple of bold executioners!... What a time we should have!"

Every afternoon the Growler and the Masher watched the road which Daubrecq took between the the Square Lamartine, the Chamber of Deputies and his club. Their instructions were to choose the most deserted street and the most favourable moment and, one evening, to hustle him into a motor-car.

Lupin, on his side, got ready an old building, standing in the middle of a large garden, not far from Paris, which presented all the necessary conditions of safety and isolation and which he called the Monkey's Cage.

Unfortunately, Daubrecq must have suspected something, for every time, so to speak, he changed his route, or took the underground or a tram; and the cage remained unoccupied.

Lupin devised another plan. He sent to Marseilles for one of his associates, an elderly retired grocer called Brindebois, who happened to live in Daubrecq's electoral district and interested himself in politics. Old Brindebois wrote to Daubrecq from Marseilles, announcing his visit. Daubrecq gave this important constituent a hearty welcome, and a dinner was arranged for the following week.

The elector suggested a little restaurant on the left bank of the Seine, where the food, he said, was something wonderful. Daubrecq accepted.

This was what Lupin wanted. The proprietor of the restaurant was one of his friends. The attempt, which was to take place on the following Thursday, was this time bound to succeed.

Meanwhile, on the Monday of the same week, the trial of Gilbert and Vaucheray opened.

The reader will remember - and the case took place too recently for me to recapitulate its details - the really incomprehensible partiality which the presiding judge showed in his cross-examination of Gilbert. The thing was noticed and severely criticised at the time. Lupin recognized Daubrecq's hateful influence.

The attitude observed by the two prisoners differed greatiy. Vaucheray was gloomy, silent, hard-faced. He cynically, in curt, sneering, almost defiant phrases, admitted the crimes of which he had formerly been guilty. But, with an inconsistency which puzzled everybody except Lupin, he denied any participation in the murder of Leonard the valet and violently accused Gilbert. His object, in thus linking his fate with Gilbert's, was to force Lupin to take identical measures for the rescue of both his accomplices.

When I arrived at Baker Street I found him huddled up in his armchair with updrawn knees, his pipe in his mouth and his brow furrowed with thought. It was clear that he was in the throes of some vexatious problem. With a wave of his hand he indicated my old armchair, but otherwise for half an hour he gave no sign that he was aware of my presence. Then with a start he seemed to come from his reverie, and with his usual whimsical smile he greeted me back to what had once been my home.

“You will excuse a certain abstraction of mind, my dear Watson,” said he. “Some curious facts have been submitted to me within the last twenty-four hours, and they in turn have given rise to some speculations of a more general character. I have serious thoughts of writing a small monograph upon the uses of dogs in the work of the detective.”

“But surely, Holmes, this has been explored,” said I. “Bloodhounds — sleuth-hounds —”

“No, no, Watson, that side of the matter is, of course, obvious. But there is another which is far more subtle. You may recollect that in the case which you, in your sensational way, coupled with the Copper Beeches, I was able, by watching the mind of the child, to form a deduction as to the criminal habits of the very smug and respectable father.”

“Yes, I remember it well.”

“My line of thoughts about dogs is analogous. A dog reflects the family life. Whoever saw a frisky dog in a gloomy family, or a sad dog in a happy one? Snarling people have snarling dogs, dangerous people have dangerous ones. And their passing moods may reflect the passing moods of others.”

I shook my head. “Surely, Holmes, this is a little far-fetched,” said I.

He had refilled his pipe and resumed his seat, taking no notice of my comment.

“The practical application of what I have said is very close to the problem which I am investigating. It is a tangled skein, you understand, and I am looking for a loose end. One possible loose end lies in the question: Why does Professor Presbury’s wolfhound, Roy, endeavour to bite him?”

I sank back in my chair in some disappointment. Was it for so trivial a question as this that I had been summoned from my work? Holmes glanced across at me.

“The same old Watson!” said he. “You never learn that the gravest issues may depend upon the smallest things. But is it not on the face of it strange that a staid, elderly philosopher — you’ve heard of Presbury, of course, the famous Camford physiologist? — that such a man, whose friend has been his devoted wolfhound, should now have been twice attacked by his own dog? What do you make of it?”

“The dog is ill.”

“Well, that has to be considered. But he attacks no one else, nor does he apparently molest his master, save on very special occasions. Curious, Watson — very curious. But young Mr. Bennett is before his time if that is his ring. I had hoped to have a longer chat with you before he came.”