The lines from "The Elements of San Joaquín" reflect the theme that the lack of concern shown by most Americans is harmful to the seasonal workers' lives through various literary devices. The simile comparing the workers' hardships to physical injuries emphasizes the pain and suffering that the workers endure, and highlights the impact of their work on their health and well-being. The word choice, such as "broken fingers" and "sleep," reflects the difficulty of the lives the workers lead, emphasizing the physically demanding and exhausting nature of their work. The repetition of the phrase "And nothing will heal" reinforces the idea that the workers' hardships will persist and continue to cause harm. The structure of the lines also highlights the contrast between the workers and other people, emphasizing the workers' invisibility and the lack of attention paid to their lives. Overall, these lines effectively communicate the theme that the lack of concern shown by most Americans towards the lives and struggles of seasonal workers is harmful and has real consequences for those who work in these conditions.