Regardless of Which Cell

A man wanted to know how one green cell finds which way is bright and swims there.

That was the question. Not memory, not fear, not a mouse gone still when the blue comes on.

At the eyespot, a gate that opens for blue and lets the charge in. For the alga, that meant: turn.

They put the gene in a frog's egg. The egg had nothing to cross, nowhere bright to get to, and opened anyway.

Then a rat's nerve cell. Then a living mouse, the light let down a fibre, and something in it, a want, a flinch, answering, on and off.

This morning Stockholm gave the gate its sentence: a new era. Nobody told the gate where it was.

In whatever room it's carried to it opens for blue, lets the charge in, and turns nothing that can swim.