Watson told us, a form of knife which is used for the most delicate operations known in surgery. And it was to be used for a delicate operation that night. You must know, with your wide experience of turf matters, Colonel Ross, that it is possible to make a slight nick upon the tendons of a horse's ham, and to do it subcutaneously, so as to leave absolutely no trace. A horse so treated would develop a slight lameness, which would be put down to a strain in exercise or a touch of rheumatism, but never to foul play."
"Villain! Scoundrel!" cried the Colonel.
"We have here the explanation of why John Straker wished to take the horse out on to the moor. So spirited a creature would have certainly roused the soundest of sleepers when it felt the prick of the knife. It was absolutely necessary to do it in the open air."
"I have been blind!" cried the Colonel. "Of course that was why he needed the candle, and struck the match."
"Undoubtedly. But in examining his belongings I was fortunate enough to discover not only the method of the crime, but even its motives. As a man of the world, Colonel, you know that men do not carry other people's bills about in their pockets. We have most of us quite enough to do to settle our own. I at once concluded that Straker was leading a double life, and keeping a second establishment. The nature of the bill showed that there was a lady in the case, and one who had expensive tastes. Liberal as you are with your servants, one can hardly expect that they can buy twenty-guinea walking dresses for their ladies. I questioned Mrs. Straker as to the dress without her knowing it, and having satisfied myself that it had never reached her, I made a note of the milliner's address, and felt that by calling there with Straker's photograph I could easily dispose of the mythical Derbyshire.
"From that time on all was plain. Straker had led out the horse to a hollow where his light would be invisible. Simpson in his flight had dropped his cravat, and Straker had picked it up--with some idea, perhaps, that he might use it in securing the horse's leg. Once in the hollow, he had got behind the horse and had struck a light; but the creature frightened at the sudden glare, and with the strange instinct of animals feeling that some mischief was intended, had lashed out, and the steel shoe had struck Straker full on the forehead. He had already, in spite of the rain, taken off his overcoat in order to do his delicate task, and so, as he fell, his knife gashed his thigh. Do I make it clear?"
"Wonderful!" cried the Colonel. "Wonderful! You might have been there!"
"My final shot was, I confess a very long one. It struck me that so astute a man as Straker would not undertake this delicate tendon-nicking without a little practice. What could he practice on? My eyes fell upon the sheep, and I asked a question which, rather to my surprise, showed that my surmise was correct.
"When I returned to London I called upon the milliner, who had recognized Straker as an excellent customer of the name of Derbyshire, who had a very dashing wife, with a strong partiality for expensive dresses. I have no doubt that this woman had plunged him over head and ears in debt, and so led him into this miserable plot."
"You have explained all but one thing," cried the Colonel. "Where was the horse?"
"Ah, it bolted, and was cared for by one of your neighbors. We must have an amnesty in that direction, I think. This is Clapham Junction, if I am not mistaken, and we shall be in Victoria in less than ten minutes. If you care to smoke a cigar in our rooms, Colonel, I shall be happy to give you any other details which might interest you."