Beauty
One of the poem's main thematic concerns is beauty. This might seem strange, given that the poem is set in the blighted back area of a hospital, but it takes this theme from a particular angle. The poem concludes with an image of fragments of green glass adrift in a pile of lifeless cinders. The speaker describes the pieces of glass as glimmering. Their momentary luster shows the presence of beauty not only in the everyday but in even the most lifeless spaces of the industrial world. He uses this specifically unappealing setting to show that beauty can occur anywhere, even in the most unexpected places.
Decay
Running somewhat in tension with the poem's theme of beauty, decay is a dominant theme throughout the text as well. The speaker sets the poem in the unseen back area of a hospital. It is full of cinders, a place where seemingly nothing can grow. It is vacant and bleak, entirely unobserved by doctors, nurses and patients. This choice of setting allows Williams to meaningfully place his central image (the shattered glass bottle) amidst the ruins of an urban space. This decision is striking in that literature often depicts images of natural beauty, but rarely does it depict something beautiful in the forgotten, disused spaces of the industrial world. In choosing a decaying space, Williams highlights a new possible place for beauty to be found.
Perseverance
Perseverance is a subtler theme within the poem. In the way that they are shown glimmering through the cracks of an abandoned area of the hospital, the shards of broken glass become a representation of how aesthetic beauty can persevere through even the bleakest of surroundings. Williams juxtaposes his description of the back wing of the hospital as a lifeless place with the shining of the shards of glass because it effectively underscores how these moments can endure their difficult settings.
