The Yazoo & Mississippi Valley Railroad Company v. Mullins case in 1918 revolved around a wrongful death claim brought by the administratrix of Mr. Mullins' estate against the railroad company, following his fatal accident while working for them as a switchman. The Supreme Court was asked to determine whether or not the Federal Employers' Liability Act (FELA) applied in this situation, which would allow Mrs. Mullins to sue for damages under federal law rather than state law - potentially leading to higher compensation if successful. The court ruled that FELA did apply because Mr. Mullins’ job involved interstate commerce, even though he was killed while switching cars within one state's boundaries only (Mississippi). This decision expanded the interpretation of "interstate commerce" under FELA and set an important precedent for future cases involving worker injuries on railroads engaged in interstate business.

In the dissenting opinion for Yazoo & Mississippi Valley Railroad Company et al. v. Mullins, 1918, it was argued that the majority's decision to uphold a verdict in favor of Mrs. Mullins was incorrect due to an error made by the trial court during jury instructions regarding contributory negligence laws in Mississippi. The dissenting justices believed that this instruction may have led jurors to believe they could not consider whether Mr. Mullins contributed to his own death through negligent behavior when deciding on liability and damages - which is contrary to state law at that time requiring such consideration in personal injury cases involving trains. They also disagreed with the majority's interpretation of relevant statutes and case law concerning railroad companies' duties towards trespassers on their property, arguing these were misapplied or misunderstood by both lower courts and their fellow Supreme Court justices.