In "A Narrow Fellow in the Grass," Emily Dickinson evokes the shivers most people experience when becoming aware of a nearby snake. Most prefer to give such creatures a wide berth, whether or not they are the venomous or harmless varieties. It is easy to understand what Emily Dickinson's young male persona means by "zero at the bone," although one regrets not possessing the genius to express the feeling so accurately and succinctly.
Nowhere in the poem is there a word like "snake," "serpent," or "reptile," all of which have negative and satanic connotations. The same applies to the verb "slither," for which the poet makes an interesting substitution. The creature she describes is a "snake in the grass," a term that has become associated with lurking evil or a faithless friend. The term was first used as a metaphor for treachery by the Latin poet Virgil in 37 BCE.