During the whole of my narration he sat as motionless as a statue, evidently committing the whole story to memory, detail by detail; and even when I had finished he remained for an appreciable time without moving or speaking.
At length he looked up at me.

"This is a very extraordinary affair, Jervis," he said.
"Very," I agreed; "and the question that is agitating me is, what is to be done ?" "Yes," he said, meditatively, "that is the question; and an uncommonly difficult question it is.

It really involves the settlement of the antecedent question: What is it that is happening at that house ?" "What do you think is happening at that house ?" I asked.
"We must go slow, Jervis," he replied.

"We must carefully separate the legal tissues from the medical, and avoid confusing what we know with what we suspect.

Now, with reference to the medical aspects of the case.
The first question that confronts us is that of sleeping sickness, or negro-lethargy as it is sometimes called; and here we are in a difficulty.