‘Grief is a Mouse’ by Emily Dickinson (1830-86) explores a range of metaphors for grief, including the idea of grief as a mouse, which ‘chooses Wainscot in the Breast / For His Shy House’. The idea is that grief is deeply felt, but hidden away: like a mouse in the wainscot, we are aware of it continually, but we never (or seldom) see it.
Grief is a Mouse—
And chooses Wainscot in the Breast
For His Shy House—
And baffles quest—