One or two of you (Tom Bliss, for instance) might have heard "Molecules" by my brother John, former MC and act booker at the Topic in Bradford. The lyrics are online on the website I did for him and I reproduce them below; some of the named references are now a tad dated (Sharon, Arafat). There's a small sample of him singing it here.

Molecules by John Waller

Where did we all come from? If you stop and think
Our bodies are entirely made of what we eat and drink
We're all built up from molecules, our flesh and bones and skin
We take them in, they stay a while, then pass from us again
   We eat we drink we breathe we grow, that's what humans do
   Then micturate and defecate and the molecules pass through

What then am I made of, what tonight is part of me?
This morning's egg and sausage, the fish I had for tea
The bread and cheese I ate last week is still making my bones strong
I've beer inside my bladder, though that won't be staying long.

Last month the egg was in a hen, the sausage was a cow
The fish was swimming in the sea, but they're all inside me now
The bread was wheat, the cheese was grass, both were miles away
The water, malt and yeast and hops hadn't reached the brewery
   We eat we drink we breathe we grow, that's what humans do
   Then micturate and defecate and the molecules pass through

So where does it all go to, when it's finished being me?
Our turds are buried in the ground, the wee flows back to sea
Both join the soil and water from which living things will grow
To be eaten by some bugger else far away who I don't know

So what this means for all of us, I've thought of it a lot
Our bodies ever melting in some vast organic pot
The molecules that currently are part of me, it's true
Tomorrow will pass out again, and will one day be in you
   We eat we drink we breathe we grow, that's what humans do
   Then micturate and defecate and the molecules pass through

So there's Jew in every Muslim, dog in every cat
There's parts of Ariel Sharon that were once in Arafat
There's black in white, Chinese in brown, it nails the racist lie
Inside every ardent feminist there are parts of macho guy

There's things in Ian Duncan Smith* that were once in Tony Blair
There's parts of Ginger Rogers that have moved through Fred Astaire
There's some of us in all of us - and what really gives me hope
Is knowing parts of Ian Paisley have been shat out by the Pope.
   We eat we drink we breathe we grow, that's what humans do
   Then micturate and defecate and the molecules pass through

* Michael Howard, David Cameron ....

Here's how he writes about it on his website: "The basic idea for this occurred to me when I was ten years old; and wondered where, exactly, all the molecules that constituted my baby brother** had been a year earlier, before he was born. It much later became the basis for a stand-up routine before ending up as this song. The concept has been approved by Biomedical Scientists and rubbished by Statisticians. But parts of it must be true.."

**ie, me

G, D, C, G;
Am, G, Am, D
Em, C, G, D, Em C, G,D,G