Final answer:
No, Montresor's sickness at heart is likely not due to the coldness of the catacombs, but rather a moment of remorse or the weight of his actions in Edgar Allan Poe's The Cask of Amontillado.
Step-by-step explanation:
Montresor's statement that his heart grew sick due to the coldness of the catacombs is highly suspect. Throughout The Cask of Amontillado by Edgar Allan Poe, Montresor exhibits calculated and cold behavior, deliberately luring Fortunato to his death. The sickness at heart he feels could more plausibly be a moment of remorse or the psychological weight of his violent act rather than a physical reaction to the environment. After all, if it were just the dampness causing his discomfort, such an explanation would likely have come to him sooner, not immediately after the final act of sealing Fortunato's fate.