What is the meaning of Peter Porter's "Killing a Mosquito"? Or what is it about?

"Killing a Mosquito"
by Peter Porter
I slap the mozzie on my hand,
the blood is mine, the black its all,
that this one second might befall;
it can't, but I can understand
the rule - in whose court is the ball?
What said of it that I should kill it
since late or soon I'd have to scratch?
No password, sesame or millet,

urged: lift the multi-treasured latch.
As well defrost a piece of fillet
and brave a blood this blood to match.
When Francis Bacon wrote that men
fear death as children fear to go
into the dark, he dipped his pen
in blood as light as ink; he'd show
the fretful soul that what might happen
was quaint as killing a mosquito.