help with a Bukowski quote

Hi, does anyone know where this Bukowski quote comes from?

"I still feel the madness rushing through me, but I haven't gotten the
word down the way I want it, the tiger is still on my back. I will die
with that son-of-a-bitch on my back but I've given him a fight. And if
there is anybody out there who feels crazy enough to want to become a
writer, I'd say go ahead, spit in the eye of the sun, hit those keys,
it's the best madness going, the centuries need help, the species cry
for light and gamble and laughter. Give it to them. There are enough
words for all of us."

Thanks very much