Here were a phial of some salt, and the record of a series of experiments that had led (like too many of Jekyll’s investigations) to no end of practical usefulness. How could the presence of these articles in my house affect either the honour, the sanity, or the life of my flighty colleague? If his messenger could go to one place, why could he not go to another? And even granting some impediment, why was this gentleman to be received by me in secret? The more I reflected the more convinced I grew that I was dealing with a case of cerebral disease; and though I dismissed my servants to bed, I loaded an old revolver, that I might be found in some posture of self-defence.

Twelve o’clock had scarce rung out over London, ere the knocker sounded very gently on the door.