Sherlock Holmes - Deductions

Now, when young ladies wander about the metropolis at this hour of the morning....
and knock sleepy people up out of their beds, I presume that it is something very pressing which they have to communicate. Should it prove to be an interesting case, you would, I am sure, wish to follow it from the outset.

“You have come in by train this morning, I see.” I observe the second half of a return ticket in the palm of your left glove. You must have started early, and yet you had a good drive in a dog-cart, along heavy roads, before you reached the station.”

“There is no mystery, my dear madam,” said he, smiling. “The left arm of your jacket is spattered with mud in no less than seven places. The marks are perfectly fresh. There is no vehicle save a dog-cart which throws up mud in that way, and then only when you sit on the left-hand side of the driver.”

“No, she was in her night-dress. In her right hand was found the charred stump of a match, and in her left a match-box.”
“Showing that she had struck a light and looked about her when the alarm took place.”

“But have you told me all?”
“Yes, all.”
“Miss Roylott, you have not. You are screening your stepfather.”
“Why, what do you mean?”
For answer Holmes pushed back the frill of black lace which fringed the hand that lay upon our visitor’s knee. Five little livid spots, the marks of four fingers and a thumb, were printed upon the white wrist.
“You have been cruelly used,”

“When you combine the ideas of whistles at night, the presence of a band of gypsies who are on intimate terms with this old doctor, the fact that we have every reason to believe that the doctor has an interest in preventing his stepdaughter’s marriage, the dying allusion to a band, and, finally, the fact that Miss Helen Stoner heard a metallic clang, which might have been caused by one of those metal bars that secured the shutters falling back into its place, I think that there is good ground to think that the mystery may be cleared along those lines.”

“Pending the alterations, as I understand. By the way, there does not seem to be any very pressing need for repairs at that end wall.”
“There were none. I believe that it was an excuse to move me from my room. Ah! that is suggestive.”

“Hum!” said he, scratching his chin in some perplexity, “my theory certainly presents some difficulties. No one could pass these shutters if they were bolted.”

“For example, what a fool a builder must be to open a ventilator into another room, when, with the same trouble, he might have communicated with the outside air!”
“That is also quite modern,” said the lady.
“Done about the same time as the bell-rope?” remarked Holmes.
“Yes, there were several little changes carried out about that time.”
“They seem to have been of a most interesting character — dummy bell-ropes, and ventilators which do not ventilate.”

“You can at least tell me whether my own thought is correct, and if she died from some sudden fright.”
“No, I do not think so. I think that there was probably some more tangible cause.”

“I knew that we should find a ventilator before ever we came to Stoke Moran.”
“Oh, yes, I did. You remember in her statement she said that her sister could smell Dr. Roylott’s cigar. Now, of course that suggested at once that there must be a communication between the two rooms. It could only be a small one, or it would have been remarked upon at the coroner’s inquiry. I deduced a ventilator.”

“I had,” said he, “come to an entirely erroneous conclusion which shows, my dear Watson, how dangerous it always is to reason from insufficient data. The presence of the gypsies, and the use of the word ‘band,’ which was used by the poor girl, no doubt to explain the appearance which she had caught a hurried glimpse of by the light of her match, were sufficient to put me upon an entirely wrong scent.
I can only claim the merit that I instantly reconsidered my position when, however, it became clear to me that whatever danger threatened an occupant of the room could not come either from the window or the door. My attention was speedily drawn, as I have already remarked to you, to this ventilator, and to the bell-rope which hung down to the bed. The discovery that this was a dummy, and that the bed was clamped to the floor, instantly gave rise to the suspicion that the rope was there as a bridge for something passing through the hole and coming to the bed. The idea of a snake instantly occurred to me, and when I coupled it with my knowledge that the doctor was furnished with a supply of creatures from India, I felt that I was probably on the right track. The idea of using a form of poison which could not possibly be discovered by any chemical test was just such a one as would occur to a clever and ruthless man who had had an Eastern training. The rapidity with which such a poison would take effect would also, from his point of view, be an advantage. It would be a sharp-eyed coroner, indeed, who could distinguish the two little dark punctures which would show where the poison fangs had done their work. Then I thought of the whistle. Of course he must recall the snake before the morning light revealed it to the victim. He had trained it, probably by the use of the milk which we saw, to return to him when summoned. He would put it through this ventilator at the hour that he thought best, with the certainty that it would crawl down the rope and land on the bed. It might or might not bite the occupant, perhaps she might escape every night for a week, but sooner or later she must fall a victim.”

“I had come to these conclusions before ever I had entered his room. An inspection of his chair showed me that he had been in the habit of standing on it, which of course would be necessary in order that he should reach the ventilator. The sight of the safe, the saucer of milk, and the loop of whipcord were enough to finally dispel any doubts which may have remained. The metallic clang heard by Miss Stoner was obviously caused by her stepfather hastily closing the door of his safe upon its terrible occupant.”