3 ideas
Arlt treats vagabondage through the streets as a discipline rather than idleness. The walker who drifts without a goal sees the 'invisible' city: its gestures, loiterers, shopfronts and small dramas. The observer who walks with a purpose filters all of that out. Knowledge of a city, and of human character, comes from exposure to accidental detail rather than from books or systematic study.
Answering critics who called porteño slang a corruption of Spanish, Arlt argues that a language belongs to the people who speak it. A language that cannot absorb the words of the street stagnates and dies. Grammarians guarding purity are like boxing theorists lecturing a champion whose unorthodox style wins fights: vitality and usage, not rules, determine what a language becomes.
Arlt sketches a Buenos Aires neighbourhood type: a man who lounges in a sleeveless mesh undershirt, idly watching the street, while his wife wears herself out ironing. His leisure rests on her labour and on the excuses he keeps ready for not finding work, so the portrait is less about calm contentment than about a comfortable idleness someone else pays for.