The appendix is not, in fact, useless | Hacker News Reader

The appendix is not, in fact, useless

npr.org

309 pointsDigit-Al157 comments

Once you understand the embryology, there are actually a variety of things like the appendix: they're just the ends of things that come together. The uvula is a great example: embryologically, the two sides of the face separate very early as an opening, then develop a lot of complicated anatomy and fuse back together. The uvula is where that fusion completes and the fusion process completes (returns 0) when the microenvironment variables get to a certain state.

The vermiform appendix is where the three tiniae coli come together. Unsurprisingly, the other, rectal, end the tiniea coli don't so much end as they spread out into the longitudinal muscular layer of the rectosigmoid.

And of course the wall of the vermiform appendix is full of lymphoid tissue. The whole colonic wall is full of lymphoid tissue!

Source: I'm a pathologist. I have looked at way too much colon. And uvula, and pretty much every other bit of tissue you can imagine, under gross exam, under a microscope, and in situ (live in ORs and dead in autopsy suites).

This idea that the vermiform appendix is some deep evolutionary mystery is sort of a low point of medicine that occasionally pokes its head up. It ranks up there with male pregnancy, and various birth defects that have given rise to stories of monsters, like Cyclops. Fun stories, completely useless. Please don't invest in anything related to any of those. If you have money burning a hole in your biomedical investment pocket, feel free to reach out.

I believe Cyclops myths were inspired by the skulls of dwarf elephants who lived on the island of Sardinia. https://greekcitytimes.com/2023/01/28/cyclops-ancient-greeks...

At first I thought the dwarf elephants would have come as a result of the Zanclean megaflood [0] of 5m years ago, which did cause some odd sized animals like the small dog sized rabbit Nuralagus [1], but the Mediterranean dwarf elephants did not appear until 2.5m years ago [2].

0. https://unchartedterritories.tomaspueyo.com/p/the-zanclean-m...

1. https://en.wikipedia.org/wiki/Nuralagus

2. https://en.wikipedia.org/wiki/Dwarf_elephant

Dwarf elephants have appeared separately in multiple places and times when full-sized elephants got stranded somewhere and their habitat / food supply was restricted. There were dwarf mammoths in the California channel islands until pretty recently (a mammoth presumably swam from the mainland when the sea level was lower and they were one big island).

For more non-elephant examples

https://en.wikipedia.org/wiki/Insular_dwarfism

In support of your scepticism I have to say there is something I'm always missing in these discussions about the alleged function of the appendix. That thing that I'm missing is a straightforward description of what are the consequences of patients losing these functions after an appendectomy. Surely there is more than enough population over which to do a case-study observational analysis? So, where is it? What happens to the immunity or gut flora of people who have had their appendices removed? Anything?

This seems similar to asking what happens if you loose a number of parts whose loss does not produce immediately discernible detriment, or perhaps parts whose function may be approximated by something else in the event of a failure.

Of course, it is a perfectly valid question to ask what the effects of losing a part are.

Hence mention of a large population who lost those parts. The actual detriment may not be identifiable in a random individual, but it will show up at scale, as the noise of other confounders will average out.

The article touches on this:

> Studies have shown that infections with the really bad, nasty bacteria C. diff tend to be higher in people who have had their appendix removed.

Thanks, I somehow missed that part. I wonder how those studies controlled for confounding factors — it could well be that a prior tendency to more Clostridium difficile infections is correlated to a tendency to get an appendix infection.

To be clear, I'm not necessarily as sceptical as GP commenter. I'm just surprised that so much talk about the actual function of the appendix appears to centre around theoreticals rather than on clinical data.

> nasty bacteria C. diff tend to be higher in people who have had their appendix removed.

Uh, because people undergoing appendectomy are, almost by definition, more likely to receive antibiotic treatment, which is a far-better documented basis for C. diff infection. This article is catastrophe.

Though I tend to agree with your train of thought, I'm always reminded of the French man who lost 90% of his brain mass yet still had a family a job and lived a normal life by all accounts. The human body can confound expectations for sure.

Sure, but outliers aside, I'd reckon you would see some sort of statistically relevant effent if you take, say, 1000 people, yank out 90% of the brain of half of them, and just watch them go about their day. (If the ethics committee would let you)

You might want to invest in some creative writing for the IRB packet for that one.

He didn't lose his brain mass, it was compressed into a thin shell around his skull.[0] Moreover, his IQ was 75 - I'm not sure ending up in the bottom 5% of human intelligence as a consequence of chronic hydrocephaly is a "normal" life.

[0] https://www.untrammeledmind.com/2018/02/so-his-brains-just-s...

Not normal, but impressive nonetheless.

So it's like how knit hats often have pompoms to hide the lumpy part where all the threads come together, but like... for bodies?

More like the lumpy part where the threads come together that the pompom is hiding

Is this part of why everyone is so anxious to hear of the baby's first bowel movement? I know it's a sign the plumbing works, but I am not sure I would have included "the plumbing is connected" under 'works'.

I always thought this was for two reasons: one as you say is to show the plumbing works, the other is because not passing the meconium (combination of stuff ingested while in the uterus) indicates other more serious conditions might exist

Newborn bowel movements are also important for preventing more serious jaundice.

There are lots of ways things don't work. The plumbing can be connected up wrong or the pumps can not work.

> Pathologist ... returns 0 when the microenvironment variables ...

Wow, and also informative and funny. This is HN in its full glory!

Sorry for the off-topic.

Looks like it returns 1, to me.

NaN

Returns 1 would be cancer, autoimmune disease, or malformation.

Awesome! Anatomy is so cool. Watching anatomy videos on YT, to me it seems like human bodies are composed of layers of biopolymers. The way all the structures are arranged and the intricacy and clean distinctness of the different layers is incredibly well organized. The human body is an amazing marvel, more so in than out in many ways.

Regarding gut bacteria, can you actually see biofilms of bacteria in the gut? Where do they reside? Or you can't tell with the eye?

Nothing you said convinces me that the uvula and appendix have no purpose. I assume that ends of things do come together a lot during development, but why does that imply no importance? Sounds like a classic case of chesterton's fence. and I hate to say it but argument from authority is pretty boring.

Is it an argument from authority or an argument from experience?

Experience would mean he's taken out a bunch of people's appendices and nothing bad has happened. Which still wouldn't prove that the appendix has no purpose at all.

He's a pathologist, so if he has removed someone's appendix they'd probably be dead. Pedantry aside, your point still stands.

I've done a fair number of autopsies and have never even heard of someone ending up on the autopsy table secondary to an appendectomy. I'm sure it's happened, but, on balance, if the docs say you need an appendectomy, they're probably right.

Just making a dumb joke that if it's the pathologist that's the person removing an appendix, they're probably dead already.

Experience can mean a lot of things.

And there is nothing in the article either that convinced you?

Yeah, it convinced me of the opposite. The appendix is probably not useless.

I think you misread GP, they only said the appendix is not an evolutionary mystery, not that it doesn't serve a purpose. In fact, he noted the presence of lymphoid tissue, which makes is useful to the organism, as stated by the article as well.

The main article claims that the appendix is not useless.

I don't think I misread GP:

  "they're just the ends of things that come together."

  [something about cyclops and male pregnancy]

  "Fun stories, completely useless"

At best it's a series of straw man arguments with sprinkles of appeal to authority.

I feel like maybe they didn't read the article and misinterpreted the double-negative in the headline.

GP here (GGP?), I read the whole article.

Mentioning their background is not necessarily an appeal to authority fallacy. It’s just metadata.

> metadata.

Exactly. Sort of like getting a picture and the metadata says "Nikon". Probably that picture didn't come from midjourney.

I read "fun stories" to refer to cyclops, male pregnancy and the deep mystery of the real purpose of the appendix. That's a plausible critique to me, and one which is compatible with the appendix being still useful. Same for the first comment you mention. Yes, it's just the ends of things that come together, but life makes use of that real-estate anyway. It's just not critical, and there is only a slight dent in immunity when removed.

They used paragraphs to separate complete thoughts.

Note, GP explicitly mentions the following in their last paragraph, and make no claims that the appendix is useless:

> This idea that the vermiform appendix is some deep evolutionary mystery is sort of a low point of medicine that occasionally pokes its head up. It ranks up there with male pregnancy, and various birth defects that have given rise to stories of monsters, like Cyclops. Fun stories, completely useless.

I've got the proof of the embryology in my throat. My uvula is partially split. See: https://my.clevelandclinic.org/health/diseases/23943-bifid-u...

As you described, nature just joints the pieces in a best effort and when it goes wrong, its never very likely to grow up to have appendictis. So the absence of anecdotes about failure is a indication of vitality of an element not of any designs.

My question: Did you discover during discection differences on the appendix depending on nutrition? Of course, people usually do have hospital meals in them when they drop by on the stainless steel desk.. none the less.. there might be bits stuck to the inflamed material..

Even if that's just a seam, so to speak, it doesn't mean it can't evolve, I guess.

So the question is: why do we have a part of the body that seems to serve no purpose besides getting infected? And if it is not, in fact, useless, what purpose does it serve? Logically it should improve survivability more than the occasional infection decreases it, otherwise it should have disappeared, or at least, be different than it is now.

Unless appendicitis is a relatively modern disease and didn't affect survivability significantly and for long enough for evolution to do its work, which is a common hypothesis.

The appendix does not evolve. The organism evolves. Logically, the genes encode proteins that respond to the local microenvironment. And that's it. The cells have no idea where they are, other than subtle cues from their neighbors. Imagine trying to build a city with no localization input except accelerometry. Theoretically, works fine. In practice, eh, there are some odds and ends left over.

Can you put the colon on the blockchain? I might know a guy.

Story begins:

>The appendix is not, in fact, useless

>It was the first day of spring break in 1992 in Phoenix, and 12-year-old Heather Smith was excited for her family's upcoming ski trip...

Immediate skip.

Almost like they were going to suggest their cooking recipe 20 paragraphs later.

> The human appendix averages 9 cm (3.5 in) in length . . . . The diameter of the appendix is 6 mm (0.24 in) . . .

You'd need a bunch of appendii for a meal. Maybe one could pan fry them with mushrooms and serve atop pasta.

No, no. You stuff it. It's the filet mignon of sausage casing.

Stuff it with ground placenta and herbs.

That's very funny, thanks for that one haha :)

+1. I was bit by an article yesterday[0] whose content begins 13 paragraphs in. Seems like this article starts only seven, shorter paragraphs in, which is more tolerable but still annoying.

[0] https://news.ycombinator.com/item?id=39248326

At least that one presented itself as a story they were telling, rather than a simple factual answer. A headline about an anatomy professor detailing the uses of the appendix doesn't seem like it'll be a meandering tale about that professor's personal experience suffering with appendicitis more than 30 years ago.

This is why many of us are excited about LLMs. This.

"Finally, I'll be able to automate turning a short science paragraph into a 10 page story with human interest content!"

Yep, it goes both ways.

* with additional fluff content because Google mandated it to show up in search results.

Seriously, the reason why all recipe sites online suddenly became autobiographies was a policy change by google prioritizing such.

Until Google uses an LLM on every indexed entry. Then people might start writing stuff for that which might correlate more with what users want to read!

I wish an LLM had obviated this thread from the discussion

So you won't have to write 10 paragraphs of inane filler, a computer will do it for you?

Humans retain knowledge better if it's attached to a story

I must not be human. For factual information of this sort I just prefer the information. The story is irrelevant and usually too mundane to be bothered with

Only if the story relates to the knowledge. Not a distracting tangent.

Luckily they labeled the sections so I just skipped to the middle with all the good stuff.

This is what happens when content is curated for Google and not human beings

How does Google preference articles with these sorts of framings/intros?

Whats the issue? Its just 1 small paragraph that goves a bit of background about the researcher. This isnt a scientific paper so a tiny bit of fluff isnt so bad.

https://www.sciencedaily.com/releases/2007/10/071008102334.h...

Date: October 8, 2007 Source: Duke University Medical Center Summary: Long denigrated as vestigial or useless, the appendix now appears to have a reason to be - as a "safe house" for the beneficial bacteria living in the human gut. The gut is populated with different microbes that help the digestive system break down the foods we eat. In return, the gut provides nourishment and safety to the bacteria. Parker now believes that the immune system cells found in the appendix are there to protect, rather than harm, the good bacteria.

A reserve of good bacteria to repopulate your guts in case you consume something bad that needs to get flushed out. Aren't tonsils something similar?

Yes, tonsils are another organ that was at one point declared useless but proved to be important.

For some definition of "important".

It fits "important". It is not essential like some organs but if it protects immune system and bacteria, it is definitely important.

Would you call helping fight infection and condition the immune system is "important"?

I would.

Only if it helps a medium-large amount.

How many percent better would you say it makes the immune system?

I'm not sure I can begin to answer that question given the immune system's complexity... How many percent smarter does your frontal lobe's top left corner make you?

> top left corner

If you have to leave in most of an organ for it to function, then it's a lot more important than an organ where you can chop out the whole thing with minimal consequences.

I don't understand why you are so invested in this argument, but I'll tell you this much: This is something I have witnessed personally, and the effects are pretty bad.

> I don't understand why you are so invested in this argument

I have so far typed four sentences, so I have no idea what you mean by that.

> This is something I have witnessed personally, and the effects are pretty bad.

Are you talking about tonsilectomy or brain damage?

Because I'm saying that losing a corner of your brain is more important than losing your tonsils. If you have evidence otherwise I'm open to hearing it..

As for the definition of 'important,' tonsils are like bouncers at the party that is your body - they keep an eye out for troublemakers and do their best to toss out any pathogens that try to crash the scene. Tonsils help activate the immune system and condition white blood cells for pathogens in the environment.

If you want an actual study, here is one example:

>Conclusion: Overall, according to these findings, CD10 as a marker of B lymphocytes in children undergoing tonsillectomy was significantly less than those healthy children. This may indicate a decrease in B cells and further reduced antibody production in these patients.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7266207/

I remember two or three times in my early life where I felt appendicitis-like symptoms only for them to go away after a few hours. That was until one night when the pains persisted past midnight. My roommate insisted on taking me to the ER. After several hours there I finally got checked in, had a CT scan, and prepped for surgery. The docs said I did indeed have appendicitis, and in fact had scarring from past episodes. Before the surgery the pain actually started to subside. I wonder if I could have moved past that episode, and if it would have hit me years later.

Yes. Appendicitis can go away on its own, and it can also be treated with antibiotics.

Doctors prefer surgery because it's a definite cure, without negative effects of a long antibiotic course.

Yes, it is possible but not likely for appendicitis to go away on its own. I mean the idea here is the likelihood of it going away on its own vs the possibility of it to burst and cause peritonitis. Doctors prefer surgery because peritonitis has a mortality rate of ~13% for < 50yo and ~30% otherwise, assuming immediate medical care and of course the surgery to clean up the burst organ.

Appendicitis going away without surgery is a common trope I heard from antivaxxers over the years. It's a very dangerous train of thought.

(someone who no longer has an appendix)

> Yes, it is possible but not likely for appendicitis to go away on its own.

Yes, that's correct. I should have specified that it's rare, and it's extremely dangerous to leave appendicitis untreated.

I was morbidly curious about how appendicitis was treated before the advent of aseptic surgery, and apparently it was mostly "just let the patient die". But several treatments seemed to help, including _massage_ of the area along with a kind of yoga-like contortions. Apparently, it sometimes could "unclog" the swollen appendix and let the pus drain into the colon.

Here's an article in JAMA that describes it: https://jamanetwork.com/journals/jama/article-abstract/44765... from 1896, no less (sidenote: and you have to pay to read it).

Another side note, I used to be a professionally certified masseur (about 20 years ago) and we were trained to recognize the signs of appendicitis. It can be almost completely asymptomatic until the appendix is almost bursting.

> Another side note, I used to be a professionally certified masseur (about 20 years ago) and we were trained to recognize the signs of appendicitis. I

Can you elaborate on that? It's interesting, because when I had appendicitis, I had just a bit of pain (which didn't go away overnight) but nothing serious. When I got to the hospital, the doctor who triaged me touched my abdomen for a few seconds and he was like 'prep this guy up'.

Yep, it's pretty common. Sometimes people don't feel acute pain at all, but a kind of soreness you feel from overworking your core muscles. That's why they go to get a massage to help them feel better.

We were taught several tests to do in this case, and immediately refer the patient to the ER if they are positive. From the memory, soreness/pain on the right side of the abdomen if the left side is pressured, and soreness/pain increasing when the pressure is removed. And some cases can apparently be palpitated directly, but I forgot what exactly it should feel like.

I went to the local clinic because I wasn't sure if my appendix was the problem. I had some signs, but others not at all. The doc pushed in on my right side, slowly. It didn't hurt, maybe a bit uncomfortable. He let of quickly and it was a short, sharp pain - that is what he was looking for. He called the ER and we drove there

The ER couldn't believe that I didn't need and pain meds. I felt nearly fine and was even hungry - apparently I shouldn't have been.

After the scan they said my appendix was huge. Easy surgery.

In hindsight, I'm sure it was acting up when I was backpacking, but I won that battle. Good thing, because I was in the middle of nowhere.

> The ER couldn't believe that I didn't need and pain meds. I felt nearly fine and was even hungry - apparently I shouldn't have been.

I could not eat for a day when it happened to me. I threw up everything I ate. That’s why my parents suspected some food-borne pathogen initially. I could not feel any pain besides the cramps at that point. We went straight to the ER in the morning when I was in such a pain that I could not put the right foot on the ground. It was indeed an appendicitis but it was apparently still far from rupturing, so it was not quite the last minute. But my goodness was it painful.

For what it's worth, I can relate to your story very much, albeit with a slight twist. The last time I experienced such intense pain, I ended up fainting (first and only instance in my life) in the ER. Consequently, surgery became a must.

IMHO, considering your past experiences with similar symptoms and existing scarring, it seems advisable to forgo the appendix, especially given your susceptibility to infection. If you hadn't done it, perhaps one of the future occasions could have ended much worse.

My brother had the same. Except the second time it hit, it almost perforated, then he got peritonitis after the surgery, so he had a second emergency surgery where they had to remove 12cm of his bowel to save his life.

Don't hesitate going to the ER if you suspect your appendix.

Even when I was a kid they were starting to understand this. I'm old enough to remember people believing it was useless, maybe even I was told it from a figure of authority at some point, but definitely as a child my memory was "people used to think it was useless, but now we know it isn't ".

It's kind if interesting to me that I continually see stories titled like the article over the years. It goes to show that undoing incorrect common knowledge is a long process that isn't really ever completed, because an editor somewhere decided that a title like this would grab people's attention, but to someone like me, this is like a headline that reads "brushing your teeth confirmed to be effective treatment in fighting tooth decay".

I've noticed a surge in articles letting me know that the appendix isn't useless, so I assume we figured out a bit better what it actually does, but to me the most interesting part is about knowledge dissemination.

I had a similar thing with whether Giant Pandas were actual bears or not when I was a kid. The genetic tests that determined they were definitely bears happened five years before I was born, but I still got taught the "We used to think they were bears, but they're actually more closely related to raccoons" version until high school.

It was a weird article. The latest study date was 2007. Maybe since then they found the c. Difícils difference??

Jupiter used to “have” twelve moons.

To this day, I still have family that think ulcers are strictly a stress and diet related thing.

I also get a bit of a smirk out of the example you use. Brushing teeth is almost certainly effective at fighting tooth problems. However, I have grown wary of it as a goto example, as I think it has long been assumed as the only thing of note there. It seems far more likely, to me, that diet and genetics play far more of an active role in tooth health. Maybe I've just had bad luck with dentists, but I swear my tooth woes only ever get significantly worse every time I see one. :(

Interesting. That said, you would expect your teeth to basically get worse over time, there's rarely anything you can do to make them actually better, assuming you're not heavily deficient in something important to them. Only thing I can think of is that I believe it's possible to regrow enamel, but don't quote me on that. Otherwise teeth just basically get worse, and it's just a question of how quickly that happens.

https://en.wikipedia.org/wiki/Dental_sealant

> Only thing I can think of is that I believe it's possible to regrow enamel, but don't quote me on that.

It’s complicated, but it does happen. Depending on the molecules in one’s mouth and its pH, the apatite on the teeth can grow. There are several toothpastes that do that.

> your teeth to basically get worse over time

Just like most of your other body parts. I'm 68, and I'd guess that every major bone in my body has been bruised at some time or other, some (like my shins and knees) multiple times in the same place. I have evidence on X-rays of hairline rib fractures that I have no memory of acquiring. One of my breasts has been removed due to cancer. As a kid I was exposed to harsh mediterranean sunshine; on every visit to my GP, he checks my moles. I've twice had polyps removed from my colon.

I'm rather surprised that I can still walk, smell, talk, hear and see.

Things are getting worse (send chocolate).

My problem there is that most dentistry related things are couched in moral failings. And people with good teeth have them due to their diligence. But... I've rarely seen evidence of this. Always posturing and admonishments.

There are dentists of the sort you can find on YouTube who say you can regrow enamel somewhat, but some of the steps go against common tooth care wisdom so personally I'd only try it if I was needing serious dental work.

It goes to show that undoing incorrect common knowledge

It's because the appendix-is-useless "belief" comes with decades of evolution vs. intelligent design emotion behind it, starting with Darwin himself.

Part of it is also that, while it does seem to help, it doesn't really have a major role in your body, and you can live a very happy and healthy life without an appendix. So, compared to virtually every other organ a regular person would know by name, saying "it doesn't have a role" is a quite good approximation. Even tonsils have a better defined and more measurable role.

> It turns out that the appendix appears to have two related functions. The first function is supporting the immune system. The appendix has a high concentration of immune tissue, so it's acting to help the immune system fight any bad things in the gut.

> The second function that it serves is what we refer to as the safe house. So this was a hypothesis that was put forward by a team from Duke University in 2007. And they argued that the appendix may serve as a safe reservoir for the beneficial gut bacteria that we have.

I have to question if the first function is valid. How can the appendix "help fight bad things in the gut" when it's basically a minor piece hanging off the large intestine. It's not like a lot of stuff passes through it or that it really secretes anything (AFAIK). In fact, wouldn't it make a little more sense that the high amount of immune tissue is there because of appendicitis? After all, people that don't die from sepsis tend to have more options to procreate and a less infect-able appendix would tend to make people live longer.

The second thing is pretty interesting though. Sort of makes sense. Though I'd imagine that more often than not the "bad bacteria" is going to infest the safe haven and kill the good gut bacteria. I can't see how that wouldn't often happen.

The immune system in the gut has a complicated roll: it doesn’t just find bacteria and yell “bacteria! We have an infection!” Thus it needs to be able to tell the good bacteria from the bad. How does it? It constantly surveils the gut flora and builds a tolerance to the regular players. When something changes then it has the opportunity figure out if this is worrisome.

Thus you can see how the appendix could be part of this surveillance mechanism. Of course we still don’t fully understand this entire system so this is all hypotheses at best.

Bacteria need to compete for resources, usually when a new bacterial strain is introduced to an environment where there's already a ton of different bacteria, the ones that are already there have adapted to live in balance with the nutrients available and the other members of the community.

A new bacterial strain must either find an open niche in that community or somehow outcompete what's already there. The ones already there generally outnumber newcomers to a significant extent.

There is no "good" or "bad" in nature, those are words that describe the human perspective and there aren't necessarily bacteria that could come in with small numbers and somehow wipe out an existing population. Its all about competition and resources

What purpose is served by the little toe?

I suspect it provides some (very) marginal help with balancing, at the cost of a microlimb that is particularly exposed to breakage by stubbing. Having broken each of my little toes by stubbing (on different occasions), I can attest that a broken little toe definitely makes it harder to balance. Hell, it makes it hard to stand.

I seriously doubt that there's enough strength in a little toe to provide much help with balancing. So given its propensity for injury, why have little toes not evolved away in large bipeds? (I don't think birds or quadripeds are prone to toe-stubbing)

It is probably linked to fingers in some gene expressions. And 5 fingers I would say is more effective than 4. So changing of number of toes might also affect fingers. So better just to keep the extra. After all it is marginal.

Doesn't necessarily need to be effective motor function: it's a probe that provides tactile feedback, both for posture and balance, as well as being the one who gets hit often - being on the outer edge - possibly saving more critical foot areas from irreparable damage. By way of consequence it's helpful when fully functional but not essential as you are prone to hit it by "design" and make it temporarily nonfunctional every so often, all without impairing the whole foot function critical for bipedal walk as humans do it. Also, redundancy: when you break some other toe you're super glad there's a pinky, however comparatively small and weak.

Anecdata: as a skateboarder it's obvious (sometimes painfully so) how every toe matters to get the most information from beneath one's feet.

Little toes significantly widen your base. Yours probably don't because you've forced them into shoes your whole life and they are crushed against the others.

When I used to windsurf, it was pretty obvious how important the little toe is for balance, it drives where to push. I can't tell you why, but it was the toe that gave back the most feedback and told me how to push with my feet

The little toe’s most important function is to remind its owner that even the most advanced being on earth can be thwarted by an inanimate object, such as the leg of a coffee table.

Primary source here:

https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.2...

The immune role of the appendix has been known for decades.

Appendicitis was around in ancient times, too, so I am not sure I understand the reference only to industrialized nations in that respect.

"Appendicitis is predominantly happening in the industrialized nations of the world — areas where fiber content of the diet tends to be lower. "

I saw it as a reference to fiber poor diets....

Perhaps, but I am somewhat surprised to see rates of appendicitis lower in the US than in Europe, for example.

while gnoshing on a French prune Me too.

"nosh" is a loanword from Yiddish, definitely no silent "g" prefix there.

Unless you're experiencing gnosis while noshing, in which case carry on. I've had prunes that good before.

If you're experiencing gnashing while noshing, then I suggest taking a break and changing to a different activity.

The last one might be gnarly.

gnash (one's teeth) and German knusen ("to chew") ought to be related with nosh and German naschen, seeing that snack in the same sense may be derived from some onomatopoeia meaning "bite". It's a non-trivial problem since these onmnomnom forms are thought to escape regular sound change. However, you may be right that silent g is inserted by mistake, but an archaic g-prefix which may be realized as /k/ is productive in Swabian, which might indicate a western Yiddish variety rather than the more eastern Ashkenaz.

Is "Knödel" related?

Related to what, Frikandel?

It doesn't say "only", it said "predominantly" and "more likely".

Not sure the data is that clear:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9758930/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9945388/

Bangladesh and Bhutan have the highest age-standardized prevalence rates, for example. One of the lower SDI cohorts seems to lead now.

I wonder whether exploratory surgery to try to "squeeze clear" any blockage might be a good idea, though it could easily be a terrible idea, no doubt.

it is, in fact, usually the most interesting part of the document

My theory:

Appendix acts like a fuse in an electric circuit.

As we get appendix infected, gotta iron out the root cause, it's a doorway to finding the lifestyle problem. Instead getting it removed (unless rarely necessary) means, certain first line of defence is taken away.

Well yeah. Half the time that's like, the best part of the book.

Haha that is how I interpreted the title too. Was thinking who in their right mind would question the value of an appendix?

It took me until the third paragraph to understand the actual topic.

I really thought this was going to be about a book appendix.

I heard that tonsils also have an immune function.

Yes, last I heard they seemed designed to catch infection and be a training ground for the immune system, so it can deal with the issue faster if that particular pathogen infects a more critical organ. Also similar to one of the reasons babies stick everything in their mouths, so they get samples of pathogens while they are healthy and can deal with it, rather than getting exposed later when they are sick and their immune system already stressed.

Natura nihil frustra facit.

Is an assumption. There is no evidence to say we are 100% optimised . Although I think it is likely.

What about vestigial stuff, like leg bones on whales?

https://www.icr.org/i/stage_248/whalelegs_stage.jpg

Similarly, what about things like congenital diseases? Why does sickle cell anemia seem to be an imperfect answer to malaria? Etc.

My suspicion is that evolution satisfices rather than optimizes, because once a trait which is in the process of changing ceases to be the limiting factor in reproduction it ceases to change rapidly. So unlike an optimizer, evolution often doesn't take free variables to extremes (eg remove the leg bones entirely) and doesn't find a global minimum, it finds a satisfactory location in phase space close to it's previous position.

Or maybe it optimizes on a higher level, and satisficing is more advantageous because optimizing to local conditions will leave you unprepared for future environmental changes, and tolerating things like vestigial traits creates opportunities for advantageous mutations. I think both explanations could coexist. This is all speculation, to be clear.

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