Nature and the unnatural

• Banquo, (1.3): "What are these o wither'd and so wild in their attire, that look not like the inhabitants o' the earth, and yet are on't?" 
• Ross (2.4): “Thou seest the heavens, as troubled with man’s act, threaten his bloody stage. By the clock ‘tis day, and yet dark night strangles the traveling lamp. Is’t night’s predominance, or the day’s shame, that darkness does the face of earth entomb, when living light should kiss it?
• Old man (2.4): “’Tis unnatural, even like the deed that’s done. On Tuesday last, a falcon, towering in her pride of place, was by mousing owl hawk’d and kill’d.”
• Old man (2.4): “'Tis said they eat each other.”
• Doctor, (5.1): “Foul whisperings are abroad, unnatural deeds do breed unnatural troubles; infected minds”