He knew why he was there.

He knew what he had done to bring him there; he realised that he had been ill a long time, many weeks.

But there was still something sinister, mysterious, crouching in the back of his mind.
The doctor sought to distract him, to rouse him.

He was a botanist, and he shewed Michael his collection of grasses.

Michael did not want to have the fatigue of looking at them, but he feigned an interest to please the doctor.