Steinbeck's use of symbolism throughout the Grapes of Wrath is indeed very evident through
simplistic use of imagery.
The grapes "filling,rotting
and growing" are symbolic of the idea that when individuals join together to form "a bunch" they develop a spirit around them.
This spirit is also reference to the soul, which is what holds all the individuals together as one. In addition, to being
surrounded by this soul, we develop a higher conscious.
pg 32-"I figgered about the Holy Sperit and the Jesus road. I figgered, 'Why do we got to hang
it on God or Jesus? Maybe,' I figgered, 'maybe it's all men an' all women we love; maybe that's the Holy Sperit-the human
sperit-the whole shebang. Maybe all men got one big soul ever'bdoy's a part of'.
pg 477- "And they stand still and watch the potatoes float by, listen to the screaming pigs
being killed in a ditch and covered with quicklime, watch the mountains of oranges slop down to a putrefying ooze; and in
the eyes of the people there is the failure; and in the eyes of the hungry there is a growing wrath. In the souls of the people
the grapes of wrath are filling and growing heavy, growing heavy for the vintage."