VVhy a Hot Iron vvould have Hiſs'd if you had but Spit upon't. The Fool carry'd this Philoſophy avvay vvith him, and took an Occaſion aftervvard to Spit in his Porridge, to try if they'd Hiſs. They did not Hiſs it ſeems, and ſo he Guttled 'em up, and Scalt his Chops.
Source: wiktionary