"But that is quite impossible. There is no such drug in the house, and
as he never leaves his room now, he could not get any from outside."

"What about the servants?" I asked.

"There are no servants excepting my housekeeper, and she is absolutely
trustworthy."

"He might have some store of the drug that you are not aware of. Is he
left alone much?"

"Very seldom indeed. I spend as much time with him as I can, and when I
am not able to be in the room, Mrs Schallibaum, my housekeeper, sits
with him."

"Is he often as drowsy as he is now?"

"Oh, very often; in fact, I should say that is his usual condition. He
rouses up now and again, and then he is quite lucid and natural for,
perhaps, an hour or so; but presently he becomes drowsy again and doses
off, and remains asleep, or half asleep, for hours on end. Do you know
of any disease that takes people in that way?"

"No," I answered. "The symptoms are not exactly like those of any
disease that is known to me. But they are much very like those of opium
poisoning."

"But, my dear sir," Mr. Weiss retorted impatiently, "since it is clearly
impossible that it can be opium poisoning, it must be something else.
Now, what else can it be? You were speaking of congestion of the brain."