It took weeks, but both times, the tips grew back perfectly round and smooth, even the fingerprints are back. The regrown tips felt a bit numb for 1-2 months, but then everything was back to normal. The second time I asked a friend, who is a medical doctor, how the body "knew" the form of the fingertip and the fingerprints. Where was this information stored? His answer was basically: we have no idea, just be grateful it works.
[0] https://www.hochland-kaffee.de/media/catalog/product/cache/1...
Here is an overview video: https://www.youtube.com/watch?v=XheAMrS8Q1c, though there are much longer lectures and papers which I would recommend if you are interested.
https://knowablemagazine.org/article/living-world/2020/how-d...
Did you just do that on your own without telling an adult? I totally did similar things.
I cut my thumb to the bone when I was 10 by whittling a stick towards myself, and I also have a fault line there now.
Out of curiosity, how did this happen? Is the opening sharp?
There's a way to check this hypothesis without cutting fingers. Salamanders can regrow tails. So get a salamander, cut its tail, use some magnetic field generator to mess with the regrowth process and see what happens.
https://wyss.harvard.edu/news/mike-levin-on-electrifying-ins...
https://www.newyorker.com/magazine/2021/05/10/persuading-the...
Fingerprints would then be where this all happens on a micro scale - Running the game of life in 3d on the cells of your body, until they reach an "end state" of a stable limit of your skin.
But, such a system can’t make discrete forms—like a nose.
There’s something else going on.
For instance... deer grow antlers every season (antlers are not horns; rather, they are complex structures with tissue, bone, skin, nerves, etc) Anyway, if a growing antler is nicked, scar tissue will form... no big deal, right? But, this is where it gets weird... When the antlers fall off and then grow the following year, the scar will be present on the new antlers. Let that sink in.
For example as you gain fat tissue you need to increase the number of capillaries feeding that tissue, which in tern needs to link up to arterioles and arteries on one side and veins on the other. https://www.ncbi.nlm.nih.gov/books/NBK53238/ This happens well into adulthood.
She was in the hospital for something different at the time so doctors were able to watch it closely. It looked really bad: blackish grey and stiff like she had gotten frostbite.
The hand specialists warned us that amputation might be necessary if it gets infected, but said ideally they just "wait and see."
Sure enough, three weeks later they were able to literally just pull off the dead part and find a new thumb growing underneath!
Here are before and after photos: https://imgur.com/a/S8hlhKz WARNING: GRAPHIC
There is more than one tale of nurses going in to rearrange the bedding or taking the gauze off only to find the affected toe had fallen off, and the patient not noticing it.
My fingertip took over 3 years to regain full feeling, and it's still slightly flattened compared to the rest of my fingers. (I made the front page of reddit with an animation of the regrowth!)
Since then I bought cut gloves because I'm now semi-phobic about using the damn thing without them.
(For anyone keeping track in this thread: the sliced portion has feeling, but no finger print, it all looks like scar tissue. The urgent care doc used a gelatin sponge (gelfoam) to stop the bleeding. Dunno if that explains the outcome)
I had to look this up because I only knew of mandolin the instrument and not mandolin the cutting tool. It did give me a very interesting mental image, though.
George Becker's book "The Body Electric" is the most complete exploration of regeneration I have encountered to date. Becker's suspicion was that we gave up general regeneration in exchange for cancer resistance.
Updates welcome! TBE deserves follow-up.
Edit: the individual was in his 50s
A year later you'd never be able to tell, rounded again with fingerprints as well. Quite amazing given I'm middle aged.
Now I can't quite remember which one it was - they are all the same and unscarred.
Lizards do it with Wnt
https://pubmed.ncbi.nlm.nih.gov/28233575/
Presumably it's only a matter of time before the penis enlargement industry discovers Wnt.
It's been that way most of my life as it happened when I was a single digit age.
If it would grow back, it should grow back with the original fingerprint.
Literally half of my nail was away with a flat surface above. Don't drive a fast scooter in flip flops!
