"We replace the rods and cones in our retina every 48 hours, so we create a lot of "sewage" in our eyes. Therefore we need a special system capable of handling all this sewage. The inside of the eye is hollow so it has the room for all this sewage. To keep it flowing, some fluid is added by the lining of the focusing muscle (ciliary body) secreting what is known as "aqueous humor". Thus aqueous humor is like extracellular fluid in the rest of the body."
METAMIA is a free database of analogy and metaphor. Anyone can contribute or search. The subject matter can be anything. Science is popular, but poetry is encouraged. The goal is to integrate our fluid muses with the stark literalism of a relational database. Metamia is like a girdle for your muses, a cognitive girdle.