window and set to work, not troubling in the least about the litter
of straw, the fire which had gone out, the box of books outside,
nor for the trunks and other luggage that had gone upstairs.

When Mrs. Hall took his dinner in to him, he was already so
absorbed in his work, pouring little drops out of the bottles into
test-tubes, that he did not hear her until she had swept away the
bulk of the straw and put the tray on the table, with some little
emphasis perhaps, seeing the state that the floor was in. Then he
half turned his head and immediately turned it away again. But she
saw he had removed his glasses; they were beside him on the table,
and it seemed to her that his eye sockets were extraordinarily
hollow. He put on his spectacles again, and then turned and faced
her. She was about to complain of the straw on the floor when he
anticipated her.

"I wish you wouldn't come in without knocking," he said in the tone
of abnormal exasperation that seemed so characteristic of him.

"I knocked, but seemingly--"

"Perhaps you did. But in my investigations--my really very urgent
and necessary investigations--the slightest disturbance, the jar
of a door--I must ask you--"

"Certainly, sir. You can turn the lock if you're like that, you
know. Any time."

"A very good idea," said the stranger.