"the twelfth house whose bell he had rung..."See in text(The Furnished Room)
Here and throughout the story the young man displays a very strong motivation to find the girl he loves. This strong motivation creates dramatic interest, even when O. Henry is describing the old building and the furnished room in elaborate detail.
"and who regarded himself as especial mastiff-in-waiting to protect the two young artists in the studio above...."See in text(The Last Leaf)
It should be noted that the old man cares about both Johnsy and Sue. This will provide him with a double motive for sacrificing his life to save Johnsy. He is not only doing it for the sick girl, but he is also doing it for Sue who is so terribly concerned about Johnsy. This double motive helps to make Behrman's noble deed more plausible.
"Old Behrman, with his red eyes plainly streaming, shouted his contempt and derision for such idiotic imaginings...."See in text(The Last Leaf)
O. Henry had to introduce the character who would paint the fake ivy leaf on the nearby wall. At the same time, the author had to forestall the possibility of the reader guessing that any painter might get the notion of painting such a leaf. O. Henry created a character who should not be suspected of doing such a thing because he is too old to be climbing ladders in the middle of a stormy night, because he is a heavy drinker, and because he expresses such contempt for the idea of anyone dying because of an ivy leaf falling off a vine.
"Those solemn but sweet organ notes had set up a revolution in him. Tomorrow he would go into the roaring downtown district and find work...."See in text(The Cop and the Anthem)
"The Cop and the Anthem" has a characteristic "O. Henry" surprise ending. In order for the surprise to work effectively, the reader must be prepared for something different. This entire paragraph is intended to prepare the reader to expect Soapy to reform. He has made a definite decision to "find work." But the inspiration of the church anthem has made him lose his hold on reality. He has, in effect, allowed himself to stray back into the middle-class world where he doesn't belong. His fantasies have made him incautious. He doesn't notice the policeman silently approaching.
Soapy felt a hand laid on his arm. He looked quickly around into the broad face of a policeman.
“What are you doin' here?” asked the officer.
“Nothin',” said Soapy.
“Then come along,” said the policeman.
This nickname suggests a lot about why Bob is wanted by the Chicago police. He acquired that nickname by being a smooth talker and a smooth operator. Although the reader is never given any specifics about Bob's activities in the West, it seems apparent that Bob was operating as a confidence man.
"then a tall man in a long overcoat,..."See in text(After Twenty Years)
The author emphasizes that the plainclothes man is bigger than Bob. This makes it less likely that Bob could make an escape. O. Henry does something similar in "A Retrieved Reformation." He emphasizes that the detective Ben Price is a "big man." This insure that Jimmy Valentine would have a hard time trying to escape being arrested.
