What can soap not disolve in animals?

What parts will not turn to sludge? Assume a strong soap made from saphonification of plant or vegetable oil with some kind of alkali. Assume also unlimited supply of soap and the luxury of time. Let’s say you want to dispose of a whole pig.

NB: I’m neither a serial killer nor a mass murderer. Nor am I contemplating a related vocation.

Soap is not particularly corrosive. All it really does is to make otherwise water-insoluble lipids behave as if they were quasi-soluble, so that they can be unstuck from surfaces and washed away. It is not going to do an animal’s skin any good to be soaked in soap for a long time, especially as soap is mildly alkaline, but the soap is never going to dissolve the animal. I am rather puzzled as to why you would think it would.

The answer to the title question is “Pretty much all of an animal cannot be dissolved by soap.”

If you do want to dissolve all or much of an animal body, you need a strong acid or a strong, caustic alkali.

If you’re going to allow unlimited time, the animal will decompose, and a lot of soap will clean up much of that (although ‘dissolve’ probably still isn’t the right word - it will emulsify the fatty bits and help to suspend some of the solids).

skip the soap and use the lye/water and you might get somewhere.

“It’s a mystery, sarge - that’s the fourth body we’ve found this month, and they’ve all been absolutely spotless…”

That’s the lye, and that’s what you want to use, not the finished soap. The soap making process neutralizes the pH, making it not so reactive to tissue. Good for cleaning, not so good for speeding up decomposition.

This is why the OP needs answer fast. :eek:

is whole pig an intact animal or the total pig in some form like homogenized?


I generally bar hand soaps that dissolve flesh; so I think acids would be your best friend.
When small I read a great deal of trash, amongst which was the first Bulldog Drummond by ‘Sapper’. It is scarcely realized today, in the corruption of manners, just how weirdly sadistic authors got from the 1880s to the 1930s ( added to which the Great War ). Apart from the joy of moralizing, it no doubt injected excitement into very tedious lives. One of the villains is in the habit of tormenting people to death in acid baths.
Guess what happens to him ?

At a minimum, you can use mild detergents to strip out all of the cells of an organ, leaving behind only the connective tissue. (It’s an experimental approach for creating “scaffolds” that you can seed with a patient’s stem cells and transplant without risk of rejection.) For a pig heart, 24 hours of perfusion with dilute detergents is all it takes (found behind the paywall in this article.)

My WAG is that longer treatments with stronger soap would reduce some organs to a few spongy shreds. However, skin, muscle, cartilage, and bone would remain mostly intact.

A lot of laundry detergents have enzymes which digest proteins. Given unlimited time, these might be able to reduce all connective tissues to gelatin, leaving only bone.

Soap is strong or weak not based on the oil but based on the Alkali used to make soap. So a Sodium hydroxide soap will be more strong (hard on the skin) than a Potassium Hydroxide soap.

The premise is wrong here. Soap does not “dissolve” fats or proteins. Think of soap like a long chain link - one end of the link loves to attach to oils (lyophillic) and the other end likes to dissolve in water (the alkali). If you keep repeatedly washing the pig with soap - more and more oils will pass on to the water - but that would be about it.

If your goal is to “dissolve” the pig, you have better chance by using the alkali to form soap with the pig’s fats etc.

This is not correct. Soap dissolves proteins quite well. It is even the basis for many standard protein biochemistry techniques which I use every day. Small, delicate tissues will completely dissolve in 10 minutes if heated in a 1% detergent solution. (It is true that proteins in connective tissue (e.g. collagen, keratin) will not be dissolved by soap alone because they are covalently cross-linked.)

Perhaps you are making a distinction between a protein or fat being “in solution” vs in a detergent micelle or emulsion? If so, it’s not a very important distinction for the OP’s question.

For examples on what perfused mild detergents do to an organ, see here. Those particular protocols have been optimized to keep the extracellular matrix intact. Longer, harsher treatments, combined with a bit of mechanical disruption, would make those decellularized organs unrecognizable.

How is that relevant to the discussion here ? The OP asked about soap not detergents with enzymes. Your link shows the effect of harsh detergent with enzymes (typically protease) on organs - it does not show the effect of SOAP.

Some organ decellularization protocols use only detergents. The first article I linked to (admittedly behind a paywall) compared three protocols. The first uses 0.1% sodium dodecyl sulfate, which is a relatively strong detergent but roughly comparable to the sodium stearate that is in ordinary soap. The second uses 0.25% sodium deoxycholate plus 0.25% Triton X-100, which are milder detergents. The third did use trypsin to digest proteins.