OUR ADVERTISEMENT BRINGS A VISITOR. Our morning’s exertions had been too much for my weak health, and I was tired out in the afternoon. After Holmes’ departure for the concert, I lay down upon the sofa and endeavoured to get a couple of hours’ sleep. It was a useless attempt. My mind had been too much excited by all that had occurred, and the strangest fancies and surmises crowded into it. Every time that I closed my eyes I saw before me the distorted baboon-like countenance of the murdered man. So sinister was the…