John Donne, in this stanza from The Ecstasy, seems to anticipate the double helix:
Our hands were firmly cemented
By a fast balm which thence did spring
Our eye-beams twisted, and did thread
Our eyes upon one double string;
So to intergraft our hands, as yet
Was all the means to make us one,
And pictures in our eyes to get
Was all our propagation.
Obviously, this says more about the perfect metaphor of the double helix than Donne’s intuitive knowledge of genetics. DNA really is the ideal molecule for the text of life: it’s so stylish, elegant and, as Donne points out, poetic.