By the time we gave up our hunt for Sholto that night and saw Hilderman into the Baltimore II. at the landing-stage, the harvest moon had splashed the mountain side with patches of silver in reckless profusion. But we were in no mood for Æsthetics. We applied the moonlight to more practical purposes.

“Show me the river, Mr. Ewart,” said Garnesk, as we turned away from the shore. Accordingly I took him up stream till we came to Dead Man’s Pool.

“What do you make of things now?” I asked, as we walked along.

“I can’t make anything of the stealing of a dog except that someone coveted it and has now got it. Can you?”

“No,” I answered thoughtfully, “I can’t. But it’s an extraordinary coincidence, at the least; and who on earth could have stolen him? You see, no one round here would dream of taking anything that belonged to Miss McLeod. And, though Sholto is well enough bred, he’s never been in a show, and has no reputation. I can’t make it out.”

“I’m very sorry it happened just now,” said the oculist. “I was in hopes that by experimenting on the animal I could cure the girl. But at any rate that is beyond grieving about now. Is this the place?”

“Yes,” I said, “this is Dead Man’s Pool. That dim white shape there is the Chemist’s Rock. It was there that Miss McLeod lost her sight, and here that the General had his extraordinary experience. It looks innocent and peaceful enough,” I added, with a sigh.

“The General was very lucky—very lucky indeed!” murmured my companion.

“Why?” I asked.

“He was down here looking at the rock, and he saw some sort of vision; Miss McLeod was up at the rock looking down at the pool, and she lost her sight. The General might have been looking this way instead of that, in which case we might have had another case on our hands.”

“Then you think the two adventures are different aspects of the same thing? If only we knew where Sholto was it might give us even more to go on.”

“Have you any tobacco?” he asked abruptly. “I’ve got a pipe, but I left my tobacco in my room.”

We were in evening dress, and my pouch and pipe were in the house; so I left him there while I ran in to fetch them. When I returned he was nowhere to be seen, and for a moment I half suspected some new tragedy; but as I looked round I caught the gleam of the moonlight on his shirt-front. I found him kneeling on the Chemist’s Rock, looking out to sea.

“Many thanks, Mr. Ewart,” he said, as he handed me back my pouch and took the light I offered him. “Ah! I’m glad to see you smoke real tobacco. By the way,” he added, “have you a friend—a real friend—you can trust?”

“I have, thank God!” I replied fervently. “Why?”

“I should like you to send for him. Do anything you can to get him here at once. Go and drag him here, if you like—only get him here.”

“But why this urgency?” I asked again. “I admit that we have some very horrible natural phenomena to deal with; but, apart from the fact that some wretched poacher has stolen a dog, we have no human element to fear. I don’t see how he can help, and he might run a risk himself.”

“Never mind—fetch him or send for him. If you could have seen yourself start when you returned to the pool yonder to find me missing, you would realise that your nervous system would be the better for a little congenial companionship. Frankly, Mr. Ewart, I don’t like the idea of you being left alone here during the next few days with a blind girl and an old man—if you’ll pardon me for being so blunt.”

“But you’ll be here,” I said; “and I hope you will have something to say to us that will put nerves out of the question when you have examined Myra.”

Garnesk rose to his feet and laid a friendly hand on my arm.

“As soon as I’ve seen what this place looks like at a quarter-past four to a quarter-past five in the afternoon I shall leave you.”

“But—good heavens, man!” I cried, aghast, “you won’t leave us like that. We hoped for so much from your visit. You can’t realise, man, what it may mean to—to us all! You see——”

“My dear chap,” said my companion, cutting me short with a laugh, “it is just because I do realise that my presence here may be dangerous to Miss McLeod that I propose to leave.”

“Dangerous to her?” I gasped. “What on earth do you mean now?” The whole world seemed to have taken leave of its senses, and I mentally vowed that I should wire for Dennis first thing in the morning.

“I say that because her dog has been drugged and taken away.”

“But some fool of a poacher was responsible for that!” I cried.

My companion looked at me thoughtfully as he puffed at his pipe.

“I was the cause of the dog’s disappearance,” he said quietly.

“I see what you’re driving at,” I said. “You pretended to steal the dog because you were afraid Myra would make overwhelming objections to your vivisecting him, or whatever you want to do. Of course, now I see you would be the only person about Invermalluch Lodge likely to have chloroform. But even then I don’t see what you mean by saying that your presence here would be dangerous to Miss McLeod.”

“That’s a very ingenious construction to put on my words, my dear fellow,” he said; “but in my mind I was relying on you to overcome my patient’s objections to any experiments that might be deemed advisable on her dog. I meant something much more serious than that. I have known you only a few hours, Mr. Ewart; but nobody need tell me you are anything of a fool, unless he wants a very flat contradiction. You are looking at this affair from a personal point of view—and no wonder, either. But if you were not so worried about your fiancÉe your brain would have grasped my point at once. That is why I want you to send for a friend.”

“I will,” I promised solemnly. “Now tell me—what did you mean?”

“When I said I was the cause of the dog’s disappearance, I meant that if I hadn’t arrived on the scene the dog would never have been touched. The dog was taken by someone who knew he was blind, who knew that I would experiment on him, and who was determined to get there first.”

“But,” I exclaimed, “that would be carrying professional jealousy a bit too far—if that’s what you mean!”

“It would be carrying it so far that we can rule it out of court,” he answered. “So that’s what I don’t mean. Let’s go back and analyse the occurrence. I say the dog was not stolen by poachers, because of the chloroform; you said the same yourself. I say that the thief knew the dog was blind, because he knew he was in a darkened room above the coach-house, and he stole him from there. A poacher would have gone to the kennel, and found it empty—and that would have been the end of that. But the man who knew the dog was in a special room must have known why he was there; and it seems to me that the man who steals a blind dog steals him because, for some reason or other, he wants a blind dog—that very one, probably. Have you got me?”

“Yes,” I said, “I follow you so far. Go on.” And I was surprised to find how relieved I was at this suggested complication. I felt that if we could only attribute this amazing week of mysteries to some human agent I should be able to grapple with it.

“Now I come to my main point,” Garnesk continued, “and it’s this: The man who wanted Sholto because he was blind wanted him to experiment on. But no professional man would do a thing like that, even supposing there to be one about. That motive again is ruled out of court. There remains one possible solution——”

“Well?” I asked breathlessly, for even now I failed to grasp the conclusion my scientific companion could be coming to. “Go on!”

“If this thief did not want Sholto to experiment on himself, he stole the dog in order to prevent me from experimenting on him.”

I laughed aloud from sheer excitement and the relief of finding some tangible thing to go on, for the oculist’s argument struck me as very nearly perfect.

“You ought to be at Scotland Yard,” I said. “You seem to me to have hit the nail on the head.”

“The two callings are very closely allied,” he said modestly. “Detectives deal with murderers and thieves, and I with nerves and tissues. It is all a question of diagnosis.”

“I must say I think you’ve diagnosed this case very well, Mr. Garnesk,” I said, “though we are just at the beginning of our troubles if what you suppose is correct.”

“I can’t think of any other solution,” he answered thoughtfully; “and we are, as you say, just at the beginning of our troubles. The first thing to do is——”

“To find the man who stole the dog,” I cut in.

“To find the man who knew the dog was blind,” he corrected. “By that means we may come to the man who stole the dog; then we may get his reason from his own lips, if we are exceptionally lucky. But I fancy I can supply his motive, failing a full confession.”

“You can?” I cried. “Let’s hear it.”

“You’ve thought of one yourself, of course?” he asked.

“The only motive I can think of is too fantastic altogether. It is weak enough to presuppose that someone has a grievance against Miss McLeod or the General, and that someone took advantage of the extraordinary circumstances to steal Sholto, and if possible prevent Myra getting her sight back. Oh, it’s too ridiculous!”

“We have to remember,” my companion suggested, “that our unknown quantity not only knew that the dog was blind, but also knew that I was coming or had arrived, and would probably experiment on the beast. It argues a very terrible urgency that the animal disappeared within an hour or two of my arrival. From all that I deduce what seems to me the only possible motive. The dog was stolen by the man who made Miss McLeod blind.”

“Made her blind!” I cried. “You don’t seriously mean that you think someone—some fiend of hell—deliberately blinded her?”

“Not deliberately,” my companion replied. “But I believe it was through some human agency that she was blinded. I think some person or persons were anxious that Miss McLeod should remain blind, in case we should, in the process of recovering her sight, hit upon the cause of her losing it.”

In silence I sat for a few moments, thinking over this extraordinary new outlook. I must certainly wire for Dennis in the morning.

“Mr. Garnesk,” I said presently, “you are bringing a very terrible charge against some human monster whom we have yet to discover. But I must admit that you seem to have logic on your side. It remains for me to discover who these people are—if there are more than one.”

“Yes,” he mused; “that is what we must discover.”

“We!” I exclaimed. “Then you’re not going away?”

“Yes,” he said. “I think it would be fairer to you all if I left you. I think my arrival has done some good—my departure may do more. But I assure you, Mr. Ewart, I shall not give up this case till Miss McLeod recovers her sight. I give you my hand on that.”

I shook hands with him warmly.

“Thank you,” I said, as I noticed the eager look on his keen, handsome face. “Thank you from the bottom of my heart. To-morrow I hope I shall find the man who knew Sholto was blind.”

“I only know of one outside the General’s household,” he answered.

“But I don’t even know that!” I cried, forgetting Dennis for the moment. As for Olvery, he had gone clean out of my mind. “Who do you mean?”

“The American,” said my companion.

“Hilderman!” I exclaimed. “Surely you must be mistaken. Why, he was absolutely astonished when we told him. He can’t have known.”

“Still,” Garnesk insisted, “I felt sure he knew. I suspected something about him, but I was wrong to do that, quite wrong; I admit that now. I couldn’t at first see why he pretended he hadn’t heard that Sholto was blind. You may have noticed that I tried to give him the impression that I had examined Miss McLeod and come to the conclusion that I could do nothing. I confess I did that to see how he took it. But I was on a wrong scent altogether. He knew about the dog, that was obvious, but it was also obvious that he hadn’t been told from an official source, so to speak. He kept fishing for information. He brought up the dog several times, each time with a query mark in his voice—as you might say. He remarked that the last time he saw Miss McLeod she had her beautiful dog with her. That made me suspicious, because from what you told me she always had her dog with her. Then he said her dog must be feeling it very keenly, you remember. I tried him with my pessimistic conclusions to see how he took it. You see, as soon as I saw the dog I put contagious disease out of the question. Natural forces unguided seemed impossible, but natural forces of some nature that we can’t yet understand seemed probable. Still I was wrong to suspect Hilderman, quite wrong. Besides he couldn’t possibly have stolen the dog.”

“I’m glad you feel you were wrong there,” I said, “because I rather like the man. I shouldn’t care to have to suspect him.”

“Don’t suspect him, whatever you do,” said the oculist earnestly. “Whatever you do, don’t do that. He might be very useful. Make a friend of him. You’ll want all your friends.”

He rose and stretched his legs, and I followed suit. We stood for a moment on the Chemist’s Rock and gazed up the river, over the top of the falls, into the silver and purple symphony of a highland night. Presently my companion turned and took my arm.

“I’ve seen all I want to see,” he said as he began to lead me down to the pool again. “They’ll wonder what has become of us. And as I’ve seen enough for one night, let’s get back to the house.”

“It’s a wonderful view at any time of the day or night,” I agreed, and I sighed as I thought of poor Myra.

“It must be,” said Garnesk absently, picking his way across the rocks. “It must be a magnificent view. I haven’t noticed it; you must bring me here to-morrow.”