How Things Work: Embalming

What happens to us after we die? Well, that’s a thorny question — one that has a lot of different answers, depending on who you ask.

There are some things we know for certain, however. When someone dies, his (or her) body begins to decompose. Depending on the environment, this can take hours, days, or weeks. A body in a steamy jungle, for example, will decompose much faster than a body in the frozen tundra.

Humans have been trying for millennia to slow or stop this process of decay. The Egyptians are famous for mummifying their dead and immortalizing the greatest of them in elaborate tombs and pyramids. Native Americans — including the Aztecs, Toltecs, and Mayans — all also had their own strategies for preserving dead bodies.

Today, we still do our best to keep bodies clean and free of rot and decay for as long as possible. Modern embalming began during the Civil War, Mary Roach writes in Stiff, a book chronicling what happens to us after we die. The Union contracted Thomas Holmes, a doctor, to find a way to preserve fallen soldiers long enough to get them home.

Holmes started embalming infantrymen in 1861. Embalming got a publicity boost at the end of the war when Abraham Lincoln’s embalmed body traveled halfway across the country, from Washington, D.C. to Lincoln’s home state of Illinois, by rail. The train made stops along the way for viewing, and those who saw Lincoln’s corpse were impressed by how well it was preserved. Although Holmes died at the age of 70 after going thoroughly insane — an unsurprising fate for the so-called “father of modern embalming” — the practice of embalming lived on.

While early embalmers claimed that embalming was permanent, today’s funeral homes set more realistic expectations. An embalmed body is meant to look fresh and (relatively) lifelike long enough for an open casket funeral service, but not much longer. Water reverses the chemical reactions that make embalming work, so when an embalmed body is buried under moist soil it soon begins to decompose in earnest. Although funeral homes sell sealed vaults and coffins, it’s hard to guarantee eternal preservation — corpses can contain bacteria spores, or DNA pods that survived the embalming process and will eventually break the body down.

There are different ways to embalm a body, but the most common method is arterial embalming. When a body is brought to a funeral home, an undertaker hooks up a pump to the corpse’s right carotid artery in the neck. The pump circulates embalming fluid, a solution of different chemicals, throughout the body.The most important ingredients in embalming fluid are preservatives, like formaldehyde and methanol. These chemicals work to kill the bacteria that cause decomposition, and keep cells from collapsing.

As a body begins to fill with embalming fluid, the skin fills out and takes on a healthy-looking red flush — embalming fluid also contains dyes to make the body look more natural. The embalmer massages the corpse to help circulate the embalming fluid and break up blood clots and, if circulation is poor, will pump fluid in through other entry points. As fluid fills the body, blood drains out through a tube in the artery.

When the fluid has been distributed through the veins, the undertaker opens the body’s main cavity and suctions out the natural fluids with a trocar, a vacuum-like instrument. The cavity is then filled with embalming fluid and sealed off.

After all of the blood and other fluids in the body have been replacing by embalming fluid, the embalmer often applies makeup to make the cadaver look its best before it’s dressed up for the funeral. The undertaker also puts cotton in the corpse’s mouth to make it look natural, avoiding the sunken cheeks so characteristic of death.

Although embalming is not the only way to deal with a dead body, it is the most common in the United States. We may never know exactly what happens to us when we die in a metaphysical sense, but we at least have the basic science of preservation down pat.