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 interstitial fluid is found in the interstitial spaces, also known as the tissue spaces. On average, a person has about 11 liters (2.4 imperial gallons or ~2.9 U.S. gal) of interstitial fluid, providing the cells of the body with nutrients and a means of waste removal.