Niter, aka potassium nitrate. It apparently wasn’t easy to breathe in the catacombs and Fortunato had asthma or something. And he was pretty drunk. IIRC Fortunato was unresponsive before Montresor even finished building the wall, I guess having worn himself out trying to escape and/or beg for his life while struggling to breathe the dank atmosphere of the catacomb.
Niter, aka potassium nitrate. It apparently wasn’t easy to breathe in the catacombs and Fortunato had asthma or something. And he was pretty drunk. IIRC Fortunato was unresponsive before Montresor even finished building the wall, I guess having worn himself out trying to escape and/or beg for his life while struggling to breathe the dank atmosphere of the catacomb.