When the windpipe is charged with air,

the entrance
of the air into the heart, though imperceptible in some animals, is
perceptible enough in the larger ones. Such are the properties of
the windpipe, and it takes in and throws out air only, and takes in
nothing else either dry or liquid, or else it causes you pain until
you shall have coughed up whatever may have gone down.

The oesophagus communicates at the top with the mouth, close to
the windpipe, and is attached to the backbone and the windpipe by
membranous ligaments, and at last finds its way through the midriff
into the belly.