Vision

The pure fire which is within
and does not burn
flows out through the eyes
and the motions caused by contact
between objects and the visual stream
produce in the soul sight.
Plato.

Light and water:
the fluid within which presses out their shape
changes every four hours
and tears salt as the sea
in which eyes first appeared
stop them drying out.

Intelligent camera.
A dimple in the nerve tissue
which forms before the brain
will become the retina.
Skin above a bulge in the brain
becomes a lens.

1352.  A church fresco in Treviso
shows two mounted lenses 
their handles riveted together
fixed before the eyes of Cardinal Ugone.
By 1600 opticians can be found
in most of the larger towns on the continent.

The pure fire.
I remember 
having been sent home from the hospital
dashing back minutes too late
for Margaret's birth.
There she sat in Louise's arms
irises glittering
like the sea alight with the early morning sky
and like both of these containing no pigment
the colour due to scattering
spectral blue
the blue of pure hydrogen's flame
living cobalt
the blue light streaming 
from her eyes into mine.