The somber images of poison and disease taint the pages of Hamlet, and shadow the corruption pervading the recent and future events of the castle. The poison with which Claudius kills King Hamlet spreads in a sense throughout the country, until "something is rotten in Denmark", as Marcellus notes (I.4.90). Shakespeare shades in words of sickness continually during the play, perhaps serving best to illustrate the ill condition of affairs plaguing not only Denmark, but the characters as well.
Shakespeare immediately conveys the sense of cold and apathy in the opening scene. As the play opens in the cool, black night, Barnardo and Francisco are high atop the looming walls of Elsinore, keeping watch for the impending revenge of enemy Fortinbras (I.1). Midnight strikes and Barnardo notes, subtly referring to the sentiment of Denmark, that "tis bitter cold, and I am sick at heart" (I.1.8). Since the beloved King Hamlet has died and the Queen remarried, the morale of the people is low, and cold. .
The act continues, and the Ghost appears out of the dark shadows (I.1). Horatio, who had doubted the men's earlier details of sightings, now contemplates the reasons for the Ghost's visit as the spirit disappears into the ramparts. He tells the men of King Hamlet's battles, and adds how the appearance of the Ghost reminds him of what he has read about the portents of Rome, just before the assassination of Julius Caesar. As "the graves stood tenantless, and the sheeted dead did squeak [the moon] was sick almost to doomsday with eclipse" (I.1.120). Horatio believes that the vision of the haunting Ghost is a forewarning to Denmark, just as the pale, sick moon was to Rome an image of the ill events to come. Even future events are drearily portrayed to the reader, a sense of the power of Fortune. This force was also referred to earlier, in Hamlet's soliloquy of the "slings and arrows of outrageous Fortune", going on to speak of being "sicklied o'er with the pale cast of thought" (III.