from Dr J Watson to Sherlock Holmes Esq:

Holmes
Glad to know you’re back in the land of the living! I did wonder quite what you were getting involved with when you agreed to Stevenson’s “experiments”. I think it was yet another of his storytelling exercises by which he persuades some dilatory individual (in this case, you) to act as guinea pig in order to throw up one of his so-called plot scenarios. I admit Holmes, I was completely taken in by what I assumed was an amusement on your part – that of substituting the experimenter for the victim – and that at any moment you would “awaken” from your apparent stupor to renounce Stevenson’s ridiculous theory of the Dark Side and expose him as a charlatan. My apologies that my observations, on this occasion, failed you and I was unable to guess how far into his sick and tormented psyche he had lured you.

 
You may be assured that I gave Stevenson a jolly good telling off – in fact, I led him away from the company and took him into the kitchen where I put him over the table and gave him a damn good licking. He won’t try that party trick again for a while, I can assure you.
I will call round in the morning with a more tangible apology, in the form of half a dozen of my wife’s muffins – which I am certain even you won’t be able to resist.

 
Watson