This story fits into the literary movement known as Naturalism, which was much in vogue in the early years of the twentieth century. Taking their cue from scientific theories such as Darwinism, Naturalist writers held that individuals were essentially dominated by forces outwith their control; that personality, actions, and eventual fate were all determined - indeed, pre-determined - by internal factors like heredity and the external effect of environment.
Naturalist writers showed a generally pessimistic view on life, with the portrayal of characters unable to control their own inherent weaknesses and also crushed by outside forces. Naturalists also often portrayed social upheaval, taking in the clash between rich and poor, conservative and radical. The French writer Emile Zola was probably the best-known exponent of this school in Europe; in America, Jack London, Theodore Dreiser and John Steinbeck all were contributors. There was also Frank Norris, who directly influenced Fitzgerald in this Naturalist phase of his career which also included the novel, The Beautiful and the Damned.
'May Day' is a Naturalist novel in its portrayal of the despairing and deteriorating character of Gordon Sterrett, who has come down in the world and who succumbs to his own inherent weaknesses, drinks heavily, and eventually commits suicide. In true Naturalist style, his fate seems more or less sealed from the beginning; there is never appears to be much hope for him. As he tells his former girlfriend, Edith:
Things have been snapping inside me for months like little hooks on a dress, and it's about to come off when a few more hooks go.
'May Day' also shares the typical Naturalist concern with violent social events. In an echo of the real-life May Day riots of 1919 in Cleveland, soldiers and socialists clash on the streets. Like other Naturalist writers, Fitzgerald here also portrays mean, ill-favoured individuals like the newly demobbed soldiers, Key and Rose, who would appear to be near the bottom of the social and biological pile. The fury of the mob in these scenes creates a sense of overlaying chaos to life, which helps to sweep along certain individuals to their doom.