A common assumption in scholarship on the plague is that early moderns failed to appreciate any etiological relationship between rats and disease. This assumption is complicated when plague is regarded as an instance of biblical "pestilence," an unstable term that can and does include famine, corrupted air, murrains, crop failures, and swarming animals. Within this theologically driven context, rats function in two ways: culturally, as mirrors of lustful, soulless, gluttonous, forever-multiplying human beings; naturally, as agents of famine, as symptoms of putrified air, or as warm-blooded disease vectors. In their obscure origins and in their ability to inflict harm on the human population both directly and indirectly, rodents bear an analogous and even homologous relationship to witches who, as King James puts it in his Demonology, are "like the Pest" (50). This essay explores the connection between rats and witches in several key texts to demonstrate how distinctions between the natural and supernatural essential to nineteenth-century germ theory were in the process of being defined during the early modern period.