Horseshoe Crab

by Kate Cheney

Color that chills,
fractures,
breaks like ice.
Not the pale
alizarin stain
of human corpuscles,
but the blue of sapphires,
delphiniums, cobalt ink:
the blood of the horseshoe
crab carries copper,
not iron—its element flows
like a scarf of sky,
or sub-zero air
under a pocket of snow.

We named them after horses,
in the days before cars,
shoveled and ground them
to fertilize farms.
To test medicine for purity,
we milk their kindness today,
strap them upended in rows to IVs,
and suck the blue from their veins,
blood more sensitive to toxins
than anything on earth.