Section 4 - Saint-Denis and Idyll of the Rue Plumet
Book Seven - Argot
The author notes that though some readers might recoil at the use of argot in a literary work he views the language of the streets and convicts as a useful tool in bringing to light the evils of society.

Analysis
The author proceeds to examine the origins and uses of several words and phrases. He concludes the book with the assertion that by bringing such things as argot into the light he is furthering the development of mankind.