Heart

A group of physical therapy interns 
          likes to exchange anecdotes of weird
science while I work my clamshell reps
          and hip flexions in the common room.
Today, it's all about 3D printing— how
          scientists have managed to reprogram
a patient's cells and engineer an entire
         heart replete with cells, blood vessels, 
ventricles and chambers. For now, the organ
          is no bigger than the heart of a rabbit 
and can only contract. They haven't 
          figured out yet how to make
the bio-inked muscles pump in that crucial
          rhythm so the thing behaves exactly
like a heart— For instance, in the evenings,
          now that it's warmer, we've seen
a rabbit and her baby come out from under
          the back deck to nibble on the clover.
The tremor under the twitch of fur is visible
          though they seem to have grown  
used to our presence and don't startle  
          as quick as they used to.  I feel my non-
printed 3D heart beat faster from my exertions, 
          and slow down as I finish. No doubt 
the goal is to someday have a science 
         that can replace a patient's failing 
internal organs without having to wait 
         for a medical chopper rushing to deliver 
a cooler packed with a lung or a liver or a heart  
         harvested from a matching donor who's just 
expired in an accident on the highway.  A miracle,
         they exclaimed, after the first human
to human heart transplant took place in South
        Africa, 1967.  A miracle, they say again, 
as the machine delivers the squishy, slightly 
        rubbery prototype— though it will take 
time to perfect this technology. I wonder how
        it will react to fire, threat, danger;  to
the glimpse of a long-missed one approaching
        after years of separation;  to the bearable
silence that makes an opening in the dappled
       leaves, some evening after sorrow.