P advertised and distributed 'Bulova' watches in the United States and foreign countries. Its advertising has penetrated Mexico. D, a resident of San Antonio, first entered the watch business there in 1922, and in 1926 learned of the trade-mark 'Bulova.' He transferred his business to Mexico City and, discovered that 'Bulova' had not been registered in Mexico. D registered the mark in 1933 in Mexico. D then imported parts from Switzerland and the United States and assembled watches in Mexico stamped with 'Bulova' and sold them as such. P received numerous complaints from retail jewelers in the Mexican border area whose customers brought in defective 'Bulovas' which upon inspection often turned out not to be products of P. P sued D in the United States. P requested injunctive and monetary relief. D challenged the court's jurisdiction over the subject matter of the suit and by interposing several defenses, including his due registration in Mexico of the mark 'Bulova' and the pendency of Mexican legal proceedings thereon, to the merits of Bulova's claim. The trial judge dismissed the complaint 'with prejudice,' on the ground that the court lacked jurisdiction over the cause. It reasoned that D had committed no illegal acts within the United States. The Court of Appeals reversed. On October 6, 1952, the Supreme Court of Mexico rendered a judgment upholding an administrative ruling which had nullified D's Mexican registration of 'Bulova.' The Supreme Court granted certiorari.