The House on the River by Fred M. White

It was a somewhat monotonous existence that Quint and his companion passed for the next two or three days. It was necessary, of course, to keep strictly within the house, the blinds of which were down, for the most part, and to look after the old gentleman who was still lying, more or less unconscious in his bedroom. He was no better and no worse, and, so far as Quint's professional training told him, was likely to remain in that condition for a considerable time to come. There was a chance, of course, that another seizure might carry him off altogether, but, on the other hand it was possible that he might before long, return to the normal. Meanwhile, he gave no trouble, he ate his food and slept for long periods without apparently being conscious of the fact that he was being waited upon by strangers.

"It's quite an ordinary case," Quint said. "He's a very old man, but evidently has taken great care of himself, and his heart and lungs are very sound."