It was quite evident that he feared, or was jealous of, some interference.

When he had got through his disgusting task, he said cheerfully, "Let the lady come in," and sat down on the edge of his bed with his head down, but with his eyelids raised so that he could see her as she entered.

For a moment I thought that he might have some homicidal intent.

I remembered how quiet he had been just before he attacked me in my own study, and I took care to stand where I could seize him at once if he attempted to make a spring at her.
She came into the room with an easy gracefulness which would at once command the respect of any lunatic, for easiness is one of the qualities mad people most respect.

She walked over to him, smiling pleasantly, and held out her hand.
"Good evening, Mr.Renfield," said she.