"You asked me how I get on; I can answer that by saying that I was never better in my life. I have been across the plains, among cowboys and Indians, and it's given me strong muscles and good health. I arrived in St. Louis this morning. It was the merest chance that placed me in a position to do you a service, Dyke. As I said before, it seems to me that you are getting careless. Just imagine what the result would have been had I not put in an appearance. I have the fellow's coat to show for the adventure." "True enough. I admit that I was careless," returned the detective, "and my adventure will serve to put me on my guard hereafter. Come with me to my room, Harry, and we will talk over matters in general. I must take the midnight express North, and may not see you again soon, unless you conclude to go on with me." "I shall remain in St. Louis for the present," returned young Bernard. He went with his friend to the hotel, however, and soon the two were in the privacy of Dyke Darrel's room. "Now, then, let us look at that coat." Harry Bernard laid the garment down on the bed, and Darrel began a close examination of the same. It was an ordinary sack coat, with two inside pockets. The detective was not long in going through the pockets. "Ah!" The ejaculation was significant. It fell from the lips of Dyke Darrel, the detective. "Now what?" questioned Bernard. "Look at that." Dyke Darrel held aloft a handkerchief that had once been white, but which was now dingy with dirt. But this was not the only discoloration. There was a stain on the square bit of linen that was significant. "What is it?" "Blood!" answered Dyke Darrel. Then the detective made a close examination, and made still another discovery--a name in one corner of the rumpled handkerchief. The keen eyes of the detective gleamed with a satisfied light. "What have you discovered, Dyke?" "A clew." "To what?" "To the most infamous crime of the century. This handkerchief has the name of its owner stamped plainly in the corner." "Well?" "Arnold Nicholson." "What?" "That is the name on this bit of linen, which shows that it was once the property of the murdered express messenger. Of course you have heard of the crime on the Central?" "Yes. It gave me a shock, too. Arnold was a good fellow." Harry Bernard's face wore a serious look as he took the blood-stained handkerchief from the hand of the detective, and examined it with mournful interest. "It must be that you were assaulted by one of the train robbers, Dyke," said the youth, as he returned the relic of that midnight crime. "I imagine so. The scoundrels have discovered that I am on the trail, and they mean to put me out on the first base, if possible. Did you see the man's face who assaulted me, Harry?" "Imperfectly. I know, however, that he had red hair." "Ah!" "You suspected as much?"