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 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.”

Lupin exclaimed:

"What! Did Daubrecq plot the present business?"

"No, no, that is only an accident. The hateful prophecy was just a wish which he expressed. But oh, how it terrified me! I was ailing at the time; my other son, my little Jacques, had just been born. And every day we heard of some fresh misdeed of Gilbert's - forgeries, swindles - so much so that we spread the news, in our immediate surroundings, of his departure for abroad, followed by his death. Life was a misery; and it became still more so when the political storm burst in which my husband was to meet his death."

"What do you mean?"

"A word will be enough: my husband's name was on the list of the Twenty-seven."

"Ah!"

The veil was suddenly lifted from Lupin's eyes and he saw, as in a flash of lightning, a whole legion of things which, until then, had been hidden in the darkness.

Clarisse Mergy continued, in a firmer voice:

"Yes, his name was on it, but by mistake, by a piece of incredible ill-luck of which he was the victim. It is true that Victorien Mergy was a member of the committee appointed to consider the question of the Two-Seas Canal. It is true that he voted with the members who were in favour of the company's scheme. He was even paid - yes, I tell you so plainly and I will mention the sum - he was paid fifteen thousand francs. But he was paid on behalf of another, of one of his political friends, a man in whom he had absolute confidence and of whom he was the blind, unconscious tool. He thought he was showing his friend a kindness; and it proved his own undoing. It was not until the day after the suicide of the chairman of the company and the disappearance of the secretary, the day on which the affair of the canal was published in the papers, with its whole series of swindles and abominations, that my husband knew that a number of his fellow-members had been bribed and learnt that the mysterious list, of which people suddenly began to speak, mentioned his name with theirs and with the names of other deputies, leaders of parties and influential politicians. Oh, what awful days those were! Would the list be published? Would his name come out? The torture of it! You remember the mad excitement in the Chamber, the atmosphere of terror and denunciation that prevailed. Who owned the list? Nobody could say. It was known to be in existence and that was all. Two names were sacrificed to public odium. Two men were swept away by the storm. And it remained unknown where the denunciation came from and in whose hands the incriminating documents were."

"Daubrecq," suggested Lupin.

"No, no!" cried Madame Mergy. "Daubrecq was nothing at that time: he had not yet appeared upon the scene. No, don't you remember, the truth came out suddenly through the very man who was keeping it back: Germineaux, the ex-minister of justice, a cousin of the chairman of the Canal Company. As he lay dying of consumption, he wrote from his sick-bed to the prefect of police, bequeathing him that list of names, which, he said, would be found, after his death, in an iron chest in the corner of his room. The house was surrounded by police and the prefect took up his quarters by the sick man's bedside. Germineaux died. The chest was opened and found to be empty."