Let's not forget about the body cavity. Arterial fluids mainly treat the skin, muscles, and organs themselves. What's inside the organs (such as urine, bile, etc.) begins to decompose. Gases and bacteria can build up and cause distention, odor, and purge (such as brown fluids coming out of the mouth - not exactly the way you want to remember grandma). These bacteria can sometimes spread to other parts of the body, even after arterial embalming, causing decomposition problems (and then sometimes legal problems for the funeral home).
Cavity treatment starts with aspirating (suctioning) fluids out of the internal organs in the abdomen and thoracic cavity. This is accomplished with the use of a trocar, a long metal tube with sharp blades at one end and a connector for a hose at the other. The hose is connected to a device that creates suction, either an electric aspirator or water powered aspirator (called a hydro-aspirator) and then connected to the trocar. The sharp blades on the trocar are used to pierce through the abdomen near the belly button. From this entry point, the embalmer directs the trocar towards and pierces all the internal organs, allowing the trocar to remain in each organ long enough to suction off the fluids.
The hose is disconnected from the aspirator and connected to an adapter that screws directly onto the bottle of cavity fluid. The trocar is once again pierced into the organs and the cavity fluid flows into them by simple gravity. Usually two bottles of full strength fluid are used to treat the entire thoracic and abdominal cavities. Cavity fluids are very similar to arterial fluids, containing about the same percentage of formaldehyde. However, cavity fluids are slightly more acidic than arterial fluids so that they produce firmer tissues in a faster time. Some cavity fluids even come with a fresh wintergreen scent!
Once the cavities have been treated, the trocar is removed and a "trocar button" is screwed into the hole in the abdomen that was used to access the organs. A trocar button looks much like a large plastic screw.
These steps apply only to a body that has not been autopsied. During autopsy all the internal organs are removed and inspected by the medical examiner and then placed back inside the body or sometimes incinerated. At the funeral home, the mortician removes the viscera and places it in a plastic bag called a "viscera bag" and allows it to soak in cavity chemical. The inside of the body cavity is aspirated with a special instrument and then coated with an embalming gel and/or an embalming powder. The treated organs are then placed back inside the body or the bag full of organs gets placed at the foot end of the casket (so NEVER try to admire the deceased's shoes!) If the viscera are not returned, then the empty cavity may be filled with adsorbent pads. In either case the autopsy opening is sutured closed and sealed.