"Spirits, when they please,

Can either sex assume, or both; so soft

And uncompounded is their essence pure,

Not tied or manacled with joint or limb,

Nor founded on the brittle strength of bones,

Like cumbrous flesh; but, in what shape they choose,

Dilated or condensed, bright or obscure,

Can execute their aery purposes,

And works of love or enmity fulfil."

Milton.