The underlined passage in "the invalid's story" is an example ofsec. 31: i found out, then, that i had spent that awful night with a harmless box of rifles and a lot of innocent cheese; but the news was too late to save me. . .

Averbal irony - the narrator says they lost their health, and they did lose their health.

Bhumor - the situation of them losing their health is humorous.

Csituational irony - in taking care of "the deceased," the characters lose their own health.