§ 2506. Limitations of suits to annul patents
Suits by the United States to vacate and annul any patent shall only be brought within six years after the date of the issuance of such patents.
(Mar. 3, 1891, ch. 559, 26 Stat. 1093; Mar. 3, 1891, ch. 561, § 8, 26 Stat. 1099.)