When Muller was decided, in 1908, there was no federal minimum wage law; such an absence permitted then-common practices like 14-year-old boys working in coal mines 12 hours per day, 7 days per week.
The case references Lochner v. New York 198 U.S. 45 1905, another important case concerning hours of the workday. In Lochner, the Court overturned a New York law that made it a criminal offense for bakers to work more than 10 hours per day and/or 60 hours per week, explaining that the benefits of workplace regulation should give way to "freedom of contract" and "economic due process." However, Lochner was eventually overruled by West Coast Hotel Co. v. Parrish, 300 U.S. 379 1937.
Argued 15 January 1908.
Handed down on 24 February 1908, the opinion of the Court was delivered by Justice Brewer.
See also:
Background
The Case
The Decision