of an ingredient not contained in the patent with one that was." Finding that the substitution of magnesium for manganese was both obvious to anyone working in the field, and was an insubstantial change, the Court upheld the finding of patent infringement. Dissent Justice Hugo Black dissented, joined by Justice Douglas. They contended that it is the responsibility of the person seeking the patent to claim everything that the patent covers, and noted that processes exist for a patent to be amended. They asserted that it was the responsibility of the Patent Office to determine the scope of the invention, and it was therefore an intrusion for courts to be expanding the scope of the patent beyond what the Patent Office has determined. Later developments The employment of this doctrine raised a great deal of controversy, as many legal commentators thought that it allowed patentees to protect more than they had specifically requested, and indeed more than they may have been permitted to request in a patent claim. The doctrine was again questioned by the Supreme Court in Warner-Jenkinson Company, Inc. v. Hilton Davis Chemical Co., which unanimously reaffirmed it, although with some refinements. See also List of United States Supreme Court cases, volume 339 References External links Linde plc 1950 in United States case law United States patent case law United States Supreme Court cases United States Supreme Court cases of the Vinson Court Welding