On July 31, 2000, Exergen Corporation filed an amendment to a patent application for a thermometer with the United States Patent and Trademark Office (PTO) in an attempt to convince the patent examiner to grant a patent. In the amendment, Exergen made the argument that "[w]hat had not been generally appreciated by those skilled in the art of temperature measurement was that the superficial temporal artery . . . provides an exceptionally reliable temperature reading." On that same day, anyone reading product descriptions on Exergen's website could have found that "[t]he temporal artery area has a long history of temperature measurement, dating back to the early centuries before Christ . . . ."