Dog Rocks Â® are a 100% natural, paramagnetic igneous rock mined from a quarry in Australia. They contain no chemicals and have been scientifically tested and proven safe for all pets.
In brief: Water. Free fluid is typically water. The lining of your abdominal contents are slippery (your bowel, the lining of your organs) and it's thus wet inside your abdomen. It's normal to have a little free fluid in one's pelvis, as that's where fluid tends to pool.
The formation of a spherical droplet of liquid water minimizes the surface area, which is the natural result of surface tension in liquids. A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, and plasma), and is the only state with a definite volume but no fixed shape.