I accompanied Holmes to the village inn, and we arranged for a room from which we could see Julia’s window at Stoke Moran. While we waited for the lantern signal, Holmes asked me to assist him with a review of the facts.
"Well, there seemed to be nothing strange about Miss Stoner’s room," I began. "But her sister Julia’s room did seem a bit odd. First of all, the bed was bolted to the floor, which prevented it from being moved. Then, of course, there was the bell rope—it didn’t even work! And, from what Miss Stoner has told us, there would be no use for it anyway. Also, there was the ventilation window that linked her room to Dr. Roylott’s."
"I think that’s everything, Watson," said Holmes. "Now, what about Roylott’s room?"
"Two things are puzzling," I replied, "the saucer of milk on the floor and the dog’s leash hanging from the bedpost."
"Indeed," said Holmes.
For several hours I sat in the armchair by the window, keeping watch for the signal as Holmes reclined on the bed with his hat tipped over his eyes. Finally he broke the silence.
"It’s going to be a dangerous night, my dear Watson," he said. "If you wish to return to the safety of London, I will not hold it against you."
"I will be at your side, Holmes!" I quickly responded. "I only wish that I could deduce more from the clues. I hate to admit it, but I don’t really know what’s happening."
Holmes gave me a kind smile. "Watson," he said, "you are a trustworthy man, a fine friend, and an excellent associate. I knew I could count on you."
Just after midnight I spotted the lantern and alerted Holmes. As he prepared his things, I slipped my pistol into the inside pocket of my suit jacket, and we left the inn. We walked along the pathway toward the window of Julia’s room, which had been left open for us. I was just about to give Holmes a boost up to the window when I noticed a hideous figure moving in the shadows.
"Oh my! What was that?" I whispered, trying hard not to appear frightened.
"It’s the baboon!" replied Holmes. "It gave me quite a fright as well."
We looked at each other and laughed softly. Then, quietly, we climbed through the window and into the room.
"It may be a while before anything occurs," advised Holmes. "Why don’t you sit in the chair and get comfortable?"
Without an explanation Holmes then placed a pack of matches next to the candles on the bedside table and lay down on the bed, holding his cane close to his side. I barely had a chance to ponder his actions before a gleam of light appeared through the ventilation window. This was accompanied by the smell of burning oil and heated metal.
"Roylott has lit his lantern," Holmes whispered. "Be prepared."
There was no further action for another few minutes. Then the silence was interrupted by an odd hissing sound much like that of a jet of steam escaping from a kettle. When Holmes heard it, he immediately leaped from the bed, lit the candles, and then lashed the bed with his cane. My heart was racing, but with all the shadows, I couldn’t see what was happening. I could tell, however, that Holmes was frightened. All the color had drained from his face. Just then a piercing scream came from Roylott’s room, and Holmes stopped.
"Is it over?" I asked frantically.
"I believe so," responded Holmes. "Follow me to the doctor’s room."
We rushed toward Roylott’s door, which luckily we discovered unlocked. Inside I was shocked to see the doctor lying face up on the floor. His face was frozen in a look of absolute terror, and he was clearly dead. Around his head was a speckled band—was this what had killed Julia too? I was about to lean down to examine it when Holmes suddenly pulled me away. Much to my surprise, the band moved! It was then that I realized the reason for Holmes’ action. It was a swamp adder, the most poisonous snake in India!
Holmes quickly stepped over the body, grabbed the leash from the bedpost, and snapped the looped end around the snake’s neck. Then he threw the serpent into the filing cabinet and closed the drawer, securing the snake inside. I gave a sigh of relief.
"Don’t worry, Watson," Holmes said. "Go get Miss Stoner and let her know that we have solved her mystery."
The next morning, after the police had been called and the two of us had given our testimony, we caught the train home to London. I took this opportunity to ask Holmes to tell me how he had known about the snake.
"Ah," he began. "I was initially confused by Miss Stoner’s mention of the Gypsies. But the more I began to research the case, the more it seemed unfair to blame the crime on them. It was obvious that Dr. Roylott had the only motive for committing the murder. At the hospital library, I learned that snake venom might also cause its victim to die without any visible sign—I have always been fascinated by toxicology! I suspected a snake could be the culprit after Miss Stoner mentioned Roylott’s love of exotic animals. Of course, when we discovered the ventilation window that connected Roylott’s room to Julia’s, I was convinced a snake was the murder weapon. I knew that serpents do not like fire, which is why I brought the pack of matches with us to the room and lit the candle."
"I see!" I exclaimed. "But what about the other clues? The bell rope, for example?"
"The bell rope worked like a bridge between the ventilation window and the bed. Roylott must have trained the snake to climb through the ventilation window and down the bell rope onto the bed, which, you will recall, was bolted to the floor. The snake must have done this for several nights without attacking, but eventually it did and poor Julia was bitten."
"How do you explain the whistling sound and the metal clang that Miss Stoner reported?" I asked. "We didn’t hear either last night."
Holmes gave me a big smile and said, "Aha! I believe that the doctor had trained the snake to return to his room when it heard the whistle—just as a snake charmer would control a cobra. The snake was rewarded each time."
"With the saucer of milk?" I asked, suddenly understanding another clue.
"Precisely. Now, remember the chair in Roylott’s room? He must have stood on it to reach the ventilation window. The clang was likely the sound of the metal window being closed after the deed had been done. However, last night, when I frightened the snake with the lit match, it retreated back up the bell rope and through the ventilation window before Roylott expected. Not only that, but I had made the snake quite angry with my cane. It attacked the first person it found—its master, Dr. Roylott!"
"Holmes," I replied, "if what you are saying is true, then you are responsible for the doctor’s death."
Holmes just laughed and said, "I suppose that is correct, but it is not a death that I will ever regret."