“I learned method among other things from my great teacher. From the time that I observed abnormality in his behaviour I felt that it was my duty to study his case. Thus I have it here that it was on that very day, July 2d, that Roy attacked the professor as he came from his study into the hall. Again, on July 11th, there was a scene of the same sort, and then I have a note of yet another upon July 20th. After that we had to banish Roy to the stables. He was a dear, affectionate animal - but I fear I weary you.”

Mr. Bennett spoke in a tone of reproach, for it was very clear that Holmes was not listening. His face was rigid and his eyes gazed abstractedly at the ceiling. With an effort he recovered himself.

“Singular! Most singular!” he murmured. “These details were new to me, Mr. Bennett. I think we have now fairly gone over the old ground, have we not? But you spoke of some fresh developments.”

The pleasant, open face of our visitor clouded over, shadowed by some grim remembrance. “What I speak of occurred the night before last,” said he. “I was lying awake about two in the morning, when I was aware of a dull muffled sound coming from the passage. I opened my door and peeped out. I should explain that the professor sleeps at the end of the passage- -”

“The date being- -?” asked Holmes.

Our visitor was clearly annoyed at so irrelevant an interruption.

“I have said, sir, that it was the night before last - that is, September 4th.”

Holmes nodded and smiled.

“Pray continue,” said he.

“He sleeps at the end of the passage and would have to pass my door in order to reach the staircase. It was a really terrifying experience, Mr. Holmes. I think that I am as strong-nerved as my neighbours, but I was shaken by what I saw. The passage was dark save that one window halfway along it threw a patch of light. I could see that something was coming along the passage, something dark and crouching. Then suddenly it emerged into the light, and I saw that it was he. He was crawling, Mr. Holmes - crawling! He was not quite on his hands and knees. I should rather say on his hands and feet, with his face sunk between his hands. Yet he seemed to move with ease. I was so paralyzed by the sight that it was not until he had reached my door that I was able to step forward and ask if I could assist him. His answer was extraordinary. He sprang up, spat out some atrocious word at me, and hurried on past me, and down the staircase. I waited about for an hour, but he did not come back. It must have been daylight before he regained his room.”

“Well, Watson, what make you of that?” asked Holmes with the air of the pathologist who presents a rare specimen.

“Lumbago, possibly. I have known a severe attack make a man walk in just such a way, and nothing would be more trying to the temper.”

“Good, Watson! You always keep us flat-footed on the ground. But we can hardly accept lumbago, since he was able to stand erect in a moment.”

“He was never better in health,” said Bennett. “In fact, he is stronger than I have known him for years. But there are the facts, Mr. Holmes. It is not a case in which we can consult the police, and yet we are utterly at our wit’s end as to what to do, and we feel in some strange way that we are drifting towards disaster. Edith - Miss Presbury - feels as I do, that we cannot wait passively any longer.”

“It is certainly a very curious and suggestive case. What do you think, Watson?”