"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 a.n.a.lyse 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 circ.u.mstances 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 quant.i.ty 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 h.e.l.l--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 a.s.sure 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."

CHAPTER VIII.

MISTS OF UNCERTAINTY.

When we got back to the house we found Myra and her father--not unnaturally--wondering what had become of us.

"What have you been doing, and where have you been, and what do you mean by it?" she asked, playfully. "I wish I could see you. I'm sure you must be looking very guilty."

Garnesk and I exchanged hurried glances. It was obvious from her remark that the General had not told her of Sholto's disappearance. I decided there and then that I would have to tell her the whole truth myself, and I gave the others a pretty broad hint that we would like to be left alone. I left the drawing-room and went with them to the library, and answered the old man's feverish questions as to the result of our search.