Now I am willing to forfeit a whole month’s salary if I have ever heard of dogs writing before. This has certainly astonished me. For some little time past I hear and see things which no other man has heard and seen.

In "The Diary of a Madman," readers begin to see the cracks in Poprishchin’s sanity appearing as he becomes convinced that he is hearing dogs speak to one another. More interestingly, he hears them discussing letters they have written to each other. While he realizes that dogs writing letters is a notable phenomenon, he does not take it as a sign that something may be wrong.

The year 2000: April 43rd.... When she learned that the king of Spain stood before her, she struck her hands together over her head and nearly died of alarm.

Poprishchin has been muddling the events occurring in Spain recently and has come to the conclusion that he is, in fact, Spain's king. His delusion is reaching a fever pitch as he descends further into madness. He has spent weeks analyzing dog handwriting and reading dogs' letters, and now his concept of time has disappeared. He has aggrandized himself to massive proportions as well, questioning at one point how he could possibly be a civil servant when he is most certainly the King of Spain. While he has been spinning further into insanity, it seems he has finally broken and is no longer sane by any definition of the word.

34 March. February 349.... They pour cold water on my head. They take no notice of me, and seem to neither see nor hear. Why do they torture me?

Sometime in the future, Poprishchin has gone fully mad. In the past, he has mentioned people coming in and checking on him, asking for the king or the titular servant. He describes them as hitting him with sticks or pouring water on his head, both of which were common techniques to try to cure mental illness at the time. It appears he is in custody and that doctors are attempting to treat his condition. Unfortunately, in those days, this "treatment" was typically a worse fate than succumbing to mental illness.