I was watching Ripley’s Believe it or Not (dubious source, I know) and they had the body of a 6 year old girl who was still completely intact after something like a century. They say the doctor who embalmed her used Arsenic, but it wasn’t used afterwards because it’s so poisonous. Any truth to the embalming properties of it?
Okay, that’s half of my less-than-ideally-worded question. Would Arsenic preserve as perfectly as this girl was supposed to be? She looked “exactly like she did the morning she was found dead in her bed”
Ah, Rosalia Lombardo. Fascinating, isn’t she?!
The short answer—yes. Arsenic is a much better long-term embalming chemical than formaldehyde. The “exactly as she looked the morning she was found” is no doubt an exaggeration, but I’m sure she looks absolutely fantastic for a girl of 95.
Long answer—embalming preserves tissues by halting decomposition. Duh. But how does it do that? Decomposition is, in the final analysis, hydrolysis–the breaking down of molecular compounds by water. Water within the tissues as well as from outside the body accomplishes this, and the action of enzymes, both the body’s own and those of various bacteria. So embalming seeks to remove water from the tissues, and to kill/deactivate enzymes and bacteria as well as rendering the tissues of the body “inedible” to them.
This is accomplished by screwing with proteins. Formaldehyde and arsenic both have an affinity for the nitrogen atoms in amino acids, they “stick” to these atoms, bond them from one protein to another, breaking the peptide bonds and releasing water, and change the proteins from liquids to solids in the process. This is about as much of the biochemistry as I understand—they don’t really go into a whole lot of detail in two-year associates degree programs 
The difference between formaldehyde and arsenic is that formaldehyde is a chemical compound—composed of several atoms—and it is very soluble in water. That’s how we get it into the tissues in the first place!! It’s nearly impossible to remove every last molecule of water from a human corpse using modern embalming techniques—the Egyptians were much, much better at permanent preservation, although their techniques didn’t exactly give the lifelike appearance that we like to try for these days. Anyway, formaldehyde bonds between these proteins can and will be reversed upon contact with water, allowing the peptide bonds to re-form and decomposition to continue.
Arsenic, on the other hand, could give two farts in a Cadillac about water. It’s an element, not a chemical compound. Any water remaining in the body will, eventually, work its way out given the right conditions, not affecting the arsenic–and the firm, inedible-to-enzymes protein structures it has created–in the least. Therefore, a corpse embalmed with copious amounts of arsenic, such as that of Rosalia Lombardo, can be embalmed once, stuck in a vault, and remain as incorruptible as a saint indefinitely, while Lenin, for instance, has to be taken out and bathed in formalin (as well as have more of it pumped through the circulatory system, but they don’t do nifty photographic features on that part of it) at least annually to maintain his non-decomposed state.
Actually, the formula used for Rosalia has since been discovered and it contains no arsenic.
From the linked article: "‘[Zinc] gave her rigidity,’ Williams said. ‘You could take her out of the casket prop her up, and she would stand by herself.’ "
Sounds like that would liven up funerals considerably - you could have the deceased standing by the podium during eulogies. 
'What did they use on Evita Peron? She was in pretty good shape…last I heard!
I want to know that they used on this thread, it looks pretty well preserved. 
I hadn’t read that yet; my recreational reading on the subject has taken a nosedive since actually going to school to study it formally
There’s been some talk about bringing back zinc chloride formulations as more people are looking for alternatives to formaldehyde, but frankly, I don’t see it happening any time soon. As hazardous as formaldehyde solutions can be (and often are) to those working with them, their major advantage is that they can’t really pollute groundwater . . . or even the water in the sewers they inevitably find themselves in as a result of the embalming process. (One of the most frequent questions I get, after “don’t you get creeped/grossed out?”, is “what happens to all of the blood and stuff you pump out of the bodies?” The answer, of course, is . . . well, what happens to all of the bodily fluids you dispose of at home? Yup—down the drain they go.) Formaldehyde has the distinct advantage of being neutralized by ammonia—found in large supply in any sewer or wastewater disposal system, and also produced in more than adequate amounts by the natural process of protein decomposition. No worries about decomposing bodies releasing formaldehyde into the ground, whether you spring for the guaranteed-leak-proof caskets and grave liners or not—by the time that becomes a concern, it’s no longer formaldehyde at all.
Sure. Zinc. She’s not a tiny vampire. Nope. Nothing to see here, move along…
Now there’s a seriously creepy story . . . Poor Eva. Her embalmer claimed in one account that he “replaced all of her blood with pure glycerin”, which is of course a bunch of hooey—we use small amounts of glycerin to keep from straight-up dessicating bodies, but it’s simply a humectant, and doesn’t have any preservative or even disinfectant qualities to speak of. In fact, given its hydroscopic qualities, I would imagine it would actually speed up decomposition when used in large amounts. He also claimed to have left her internal organs intact, which also sounds like a bit of morbid/romantic fiction. Depending on various factors, we often have to aspirate those areas an extra time or two between the initial embalming and final disposition.
Whatever Pedro Ara used, it took him nearly two years–or so he claimed–to complete the process. (Of course, it’s also said that the bill came to around $100,000—and people say the modern American funeral industry takes folks to the cleaners!) And it was apparently a good enough job that one of her caretakers is rumored to have . . . um . . . developed some fairly creeptastic attachments to her corpse.
I wonder how well silica gel would work. I have this vision of eventually (years or decades) petrifying the body to the point where it would last for geologic ages.