Polysyndeton is the use of conjunctions (such as and and or) in close proximity even though they are not needed. Their use, then, is for literary effect or impact rather than for necessity. Compare the following two sentences:
- I'm tired, hungry, and thirsty.
- I'm tired and hungry and thirsty.
While the same information is contained in these two sentences, it is quite evident in the second sentence that the speaker is seriously tired, hungry, and thirsty--and he wants that situation to change now.
Chapter three of The Great Gatsby by F. Scott Fitzgerald begins with a description of Gatsby's parties. We learn that they are lavish and extravagant in nearly every way, from the preparations to the guests, so we should not be surprised to find that Fitzgerald used many examples of polysyndeton in his description of them. [i am adding the bold typeface to all of the following sentences from the novel.]
[A] bar with a real brass rail was set up, and stocked with gins and liquors and with cordials so long forgotten that most of his female guests were too young to know one from another.
The result of the repeated ands here suggests the superabundance of alcoholic beverages (during a time of Prohibition, remember). This implies the power, influence and money Gatsby had, but it also suggests that the guests are probably going to be getting drunk at the party.
The same principle is true about the music Gatsby has hired to play at his party:
[T]he orchestra has arrived, no thin five-piece affair, but a whole pitful of oboes and trombones and saxophones and viols and cornets and piccolos, and low and high drums.
The music for Gatsby's party is not just some little trio who can barely be heard by the crowd; this is a significant number of musicians who will be providing significant music for this gathering.
One final example can be found in the following two sentences. The first use of polysyndeton demonstrates the size and grandness of Gatsby's mansion. and the colorful spectacle it will be. The second example uses this repetition technique to paint a vivid picture of the kinds of things that will happen at Gatsby's party.
[A]lready the halls and salons and verandas are gaudy with primary colors, and hair shorn in strange new ways, and shawls beyond the dreams of Castile. The bar is in full swing, and floating rounds of cocktails permeate the garden outside, until the air is alive with chatter and laughter, and casual innuendo and introductions forgotten on the spot, and enthusiastic meetings between women who never knew each other’s names.
Notice that the second sentence is a list which Fitzgerald uses to draw his readers a word picture of these lavish parties which Gatsby regularly hosts. His guests share chatter, laughter, casual innuendo, introductions, and meetings. Notice the list I just wrote contains the same basic information but is not nearly as impactful as the list Fitzgerald gave his readers. Part of that is his use of polysyndeton.
You can certainly find other examples of polysyndeton in this and other chapters of the novel, but it is the perfect literary device to use when describing Gatsby's outrageously over-the-top parties.
Check out the excellent eNotes sites, attached below, for more discussion of Fitzgerald and his masterpiece, The Great Gatsby.