Final answer:
Kerouac's writing style in 'The Railroad Earth' demonstrates the influence of blues and jazz, particularly through spontaneous and rhythmic phrasing reflective of musical improvisation.
Step-by-step explanation:
The influence of American blues and jazz on Jack Kerouac's style is most vividly illustrated by the rhythm and improvisational tone in his writing, particularly in phrases that echo the spontaneity and cadences of this music genre. For instance, consider the line: "i put the light out on the sad dab mad grub little diving room and hustle out into the fog of the flow o well anyway" from "The Railroad Earth." This passage reflects the cadence and spirit of blues and jazz through its spontaneous phrasing and rhythmic use of language, characteristic of Kerouac's stream-of-consciousness approach inspired by musical improvisation.