Things had indeed been very slow with us, and I had learned to dread such periods of inaction, for I knew by experience that my companion’s brain was so abnormally active that it was dangerous to leave it without material upon which to work. For years I had gradually weaned him from that drug mania which had threatened once to check his remarkable career. Now I knew that under ordinary conditions he no longer craved for this artificial stimulus, but I was well aware that the fiend was not dead but sleeping, and I have known that the sleep was a light one and the waking near when in periods of idleness I have seen the drawn look upon Holmes’s ascetic face, and the brooding of his deep-set and inscrutable eyes. Therefore I blessed this Mr. Overton whoever he might be, since he had come with his enigmatic message to break that dangerous calm which brought more peril to my friend than all the storms of his tempestuous life.