And when the heart dilates to draw in the stream of dark blood, it opens its arms as to a beloved.

It dilates with reverent joy, as a host opening his doors to an honored guest, whom he delights to serve: opening his doors to the wonder which comes to him from beyond, and without which he were nothing.
So it is that our heart dilates, our lungs expand.

They are bidden by that great and mysterious impulse from the cardiac plexus, which bids them seek the mystery and the fulfillment of the beyond.

They seek the beyond, the air of the sky, the hot blood from the dark under-world.
And so we live.
And then, they relax, they contract.

They are driven by the opposite motion from the powerful voluntary center of the thoracic ganglion..
That which was drawn in, was invited, is now relinquished, allowed to go forth, negatively.