And, suddenly, Lupin remembered: two years ago, Prasville and Daubrecq the deputy had had a personal encounter on the Place du Palais-Bourbon. The incident made a great stir at the time. No one knew the cause of it. Prasville had sent his seconds to Daubrecq on the same day; but Daubrecq refused to fight.

A little while later, Prasville was appointed secretary-general.

"Very odd, very odd," said Lupin, who remained plunged in thought, while continuing to observe Prasvile's movements.

At seven o'clock Prasville's group of men moved away a few yards, in the direction of the Avenue Henri-Martin. The door of a small garden on the right of the house opened and Daubrecq appeared. The two detectives followed close behind him and, when he took the Rue-Taitbout train, jumped on after him.

Prasville at once walked across the square and rang the bell. The garden-gate was between the house and the porter's lodge. The portress came and opened it. There was a brief conversation, after which Prasville and his companions were admitted.

"A domiciliary visit," said Lupin. "Secret and illegal. By the strict rules of politeness, I ought to be invited. My presence is indispensable."

Without the least hesitation he went up up to the house, the door of which had not been closed, and, passing in front of the portress, who was casting her eyes outside, he asked, in the hurried tones of a person who is late for an appointment:

"Have the gentlemen come?"

"Yes, you will find them in the study."

His plan was quite simple: if any one met him, he would pretend to be a tradesman. But there was no need for this subterfuge. He was able, after crossing an empty hail, to enter a dining-room which also had no one in it, but which, through the panes of a glass partition that separated the dining-room from the study, afforded him a view of Prasville and his five companions.

Prasville opened all the drawers with the aid of false keys. Next, he examined all the papers, while his companions took down the books from the shelves, shook the pages of each separately and felt inside the bindings.

"Of course, it's a paper they're looking for," said Lupin. "Bank-notes, perhaps... "

Prasville exclaimed:

"Whatrot! We shan't find a thing!"

Yet he obviously did not abandon all hope of discovering what he wanted, for he suddenly seized the four bottles in a liqueur-stand, took out the four stoppers and inspected them.

"Hullo!" thought Lupin. "Now he's going for decanter-stoppers! Then it's not a question of a paper? Well, I give it up."

Prasville next lifted and examined different objects; and he asked:

"How often have you been here?"

"Six times last winter," was the reply.

"And you have searched the house thoroughly?"

"Every one of the rooms, for days at a time, while he was visiting his constituency."

"Still... still ... ." And he added, "Has he no servant at present?"

"No, he is looking for one. He has his meals out and the portress keeps the house as best she can. The woman is devoted to us... "

Holmes looked thoroughly surprised at Miss Presbury’s narrative.

“My dear young lady, you say that your room is on the second floor. Is there a long ladder in the garden?”

“No, Mr. Holmes, that is the amazing part of it. There is no possible way of reaching the window — and yet he was there.”

“The date being September 5th,” said Holmes. “That certainly complicates matters.”

It was the young lady’s turn to look surprised. “This is the second time that you have alluded to the date, Mr. Holmes,” said Bennett. “Is it possible that it has any bearing upon the case?”

“It is possible — very possible — and yet I have not my full material at present.”

“Possibly you are thinking of the connection between insanity and phases of the moon?”

“No, I assure you. It was quite a different line of thought. Possibly you can leave your notebook with me, and I will check the dates. Now I think, Watson, that our line of action is perfectly clear. This young lady has informed us — and I have the greatest confidence in her intuition — that her father remembers little or nothing which occurs upon certain dates. We will therefore call upon him as if he had given us an appointment upon such a date. He will put it down to his own lack of memory. Thus we will open our campaign by having a good close view of him.”

“That is excellent,” said Mr. Bennett. “I warn you, however, that the professor is irascible and violent at times.”

Holmes smiled. “There are reasons why we should come at once — very cogent reasons if my theories hold good. To-morrow, Mr. Bennett, will certainly see us in Camford. There is, if I remember right, an inn called the Chequers where the port used to be above mediocrity and the linen was above reproach. I think, Watson, that our lot for the next few days might lie in less pleasant places.”

Monday morning found us on our way to the famous university town — an easy effort on the part of Holmes, who had no roots to pull up, but one which involved frantic planning and hurrying on my part, as my practice was by this time not inconsiderable. Holmes made no allusion to the case until after we had deposited our suitcases at the ancient hostel of which he had spoken.

“I think, Watson, that we can catch the professor just before lunch. He lectures at eleven and should have an interval at home.”

“What possible excuse have we for calling?”

Holmes glanced at his notebook.

“There was a period of excitement upon August 26th. We will assume that he is a little hazy as to what he does at such times. If we insist that we are there by appointment I think he will hardly venture to contradict us. Have you the effrontery necessary to put it through?”

“We can but try.”

“Excellent, Watson! Compound of the Busy Bee and Excelsior. We can but try — the motto of the firm. A friendly native will surely guide us.”