I thought I'd do something a little special for #1000, so I painted this in watercolours. Clearly I need more practice. I had visions of a sweeping, majestic landscape of subtle tints and skilful brushwork, but you ended up with this.

Oh, and the four humours of ancient medicine were four bodily fluids believed to maintain a dynamic balance based on one's diet and activity levels, and to affect one's personality and disposition. They fluids in question are blood, bile, phlegm, and black bile.

It turns out black bile is particularly hard to illustrate, since it doesn't actually exist. It was thought to occur in the spleen though (which is actually part of the lymphatic system, lymph being essentially leftover blood plasma after it oozes out of the semi-permeable bits of the circulatory system).

Bile is tricky too, since normally it's only added to digested food after it leaves the stomach, in the duodenum, so it actually isn't that common as a component in vomit. It can however be brought up in extreme cases of vomiting through duodenal contraction that forces it back up into the stomach. And it was easier painting a guy vomiting than a gall bladder.

Hmmm. I really hope you're not eating dinner right now.