When reading "The Black Cat" it can be noticed how the narrator is totally aware of his mental sickness and deterioration, and at particular moments through the story, he admits the change that is taking over him. Then, he attempts to do something about it, but he finds himself unable to reverse his falling into madness.
Curiously, the narrator had a special relationship with Pluto, the cat, which had endured for years. Suddenly, one day the narrator, due to the influence of alcohol, made a vast change. In fact, he says: "I grew, day by day, more moody, more irritable, more regardless of the feelings of others." Thus, Poe pointed out that a man had the power of having an undergoing reversal of personality and of falling into a state of madness at any moment. In this sense, the narrator focuses on that change. As a result, when he returned home drunk he grasped the cat by its throat and with a pen knife cut out one of its eyes. This act of perversity is just the beginning of several such acts which will characterize the "totality of effect" that Poe wanted to achieve in this story.
What is more, next morning he pointed out that he was abruptly horrified by what he had done. After the brutal accident of losing of the eyes, the cat avoided the narrator. Meantime, the spirit of perverseness overcame him again — this time, with an unfathomable longing of the soul to "offer violence . . . to do wrong for the wrong's sake only."