Classic post on nasal mucus

Re: Cecil’s article nasal mucus,

What are the properties of the non-water ingredients (mostly proteins, I guess) of mucus that allow a body to make so much of it? A little of the non-water ingredients must go an amazingly long way. I was surprised at the small amount of mucus that the human body creates, even during a cold. However, there are animals that can create huge amounts of mucus. Here I think of gastropods and hagfish. A slug leaves a trail of mucus that it secretes in order to move, and even a small hagfish can turn a five-gallon bucket of seawater to snot in about a minute. The amount of protein needed to cause the gellatinization of large amounts of water must be very small, otherwise these animals would exhaust their supplies quickly. How does this work?

Well, according to Beakman, you need 3 envelopes of Knox gelatin to 1/2 cup of water and 1 cup of corn syrup.
Whip Up Some Fake Snot !

A lot of it is sugars and glycoproteins (proteins attached to sugars). Neuraminic acid, for instance. As for how so much is produced, well, animals that do that just have a lot of cells devoted to making the stuff. No big mystery. There’s no danger of exhausting a supply, since they make it as it’s needed.

Thanks, but neither of those really answers the question…

Duck, Given Beakman’s recipe, and assuming that recipe makes about two cups and doesn’t expand like the dickens (which I doubt), and guessing that a package of Knox gelatin (about pure protein) weighs in at about an ounce, for a 1-pound hagfish to turn a five gallon bucket of seawater into snot, it would take about 8 recipes/gallon, and about 3oz gelatin per recipe, totalling about 120 oz of protein (and a lot of sugar) to come from a 1-pound fish. Granted, I don’t know the consistency of Beakman’s snot compared to that of a hagfish. But I think the volumes are way off here.

Smeghead, there is no danger of exhausting the supply until you run out of ingredients. Only by making mucus very efficiently, with a very low protein and sugar to water ratio, could this be done. That is what I am asking. How do these animals make such an inconcievably (to me) large amount of mucus without exhausting their limited resources. I guess it could come down to a very complex chemical/physical answer, but I may be capable of understanding it.

A couple of hagfish links:

I’ve never been on a boat that specifically targeted hags, but I’ve seen pictures of the traps being hauled up with multiple slime strings over 10 foot long hanging off of the traps. Got to be a fun job, that.

Re Cecil’s statement that “on the peak day of a cold the average person produces about 14 grams of drippings, or roughly half an ounce”.

My butt.

On the peak day of one of my colds I can produce an half ounce of snot per nostril per blow. Sometime this winter I’ll be able to produce the Kleenex to prove it.

Don’t even talk to me about lungers…

Hmm. Here is a fairly technical site, a course outline for the Biology 353/355 course, Winter Term, 2001 at the Zoology Department, University of British Columbia, that promises that at the end of the Lesson,

This probably has more than you wanted to know about how mucus cells do their job. I don’t see anything that specifically answers your question about “how much protein does it take to make mucus”. Some information just isn’t posted on the Web.

If you really want to know more about mucus (I found this during a Google search for “composition slug slime”), you could probably e-mail one of the professors listed on the Home Page.

I had always thought that the increased mucus flow in the nose was the cold viruses way of proliferating/reproducing itself, as opposed to the bodies defense mechanism going into high gear. I know without a doubt that cold viruses DO use the mucus to spread infection (see: However, there seems to be no indication that the increased mucus flow actually shortens the cycle of the virus, or prevents virus infection. Neither does treating the increased nasal secretion symptoms seem to effect the duration of the cold. So is the buckets of snot you generate REALLY your body trying to fight the cold, or the cold using your bodies defenses to spread itself to other persons? I found the Cecil answer lacking in this regard.

As for the mass of proteins needed to generate snot: consider snot to be mostly water (say 95 to 98%) and calculate the mass of protein/water needed for say a hagfish to produce a cup of the stuff. I get roughly 15 to 22 grams of protein to 440 to 433 grams of water. Not really a big deal. Even if the percentage is off a bit (say it is 93% or 99% water) it still doesn’t take much to make alot of snot.

A cup of the stuff is nothing - a 1# hagfish can produce buckets of the stuff. I have placed a hagfish into a five gallon bucket of salt water, left him for a few minutes, and upended the bucket on the dock as demonstration. The hagfish will slither right out of the slime, but all of the contents of the bucket are now viscous and will only slowly drip through the slats in the dock. So if glycoproteins make up 2% of the slime by weight, and 5gallons of seawater weighs @44 pounds, then the 16 oz fish would have to cough up 14 oz of biologically expensive ingredients. And it can do this repeatedly, although I do not know the limits. So the percentage of protein has to be an order of magnitude or two lower than the suggested 95 to 98%, or the fish just would never be able to do this. If I was still coastal, I could dry some of the slime out and find out how much exactly, but hagfish are tough to get in Missouri. I probably know someone who could do this for me (but would he? - would you?). Maybe I will email around for some answers. They must produce some protein which is remarkably efficient at congealing water. I’d be willing to bet that snails and slugs have a similar efficiency and even that the chemical mechanisms are similar, but it is a guess. Spending too much time on this though, so maybe knowledge will have to wait.

Dammit, Fishhead, now you’ve got me looking up my old notes. But first let me respond to Gone.

I’m not entirely sure what you mean by viruses using mucus to spread. Cold viruses spread through aerosol. Sneezing is the best method. I imagine you’re referring to dirty hands and tissues and stuff that have infected mucus on them. Sneezing and mucus are indeed defensive mechanisms that help get the virus out of the body. Or at least out of the areas that it can infect. My body doesn’t really care if I happen to infect your body, as long as I get better. So viruses can take advantage of these mechanisms, but as far as my body is concerned, it’s purely defensive.

Now, Fishhead, I’ve got to look up the name of the molecule that is so good at absorbing water. Hold on. Ah, here it is. In the human extracellular matrix are structures known as proteoglycans, which have kind of a Christmas-tree like structure of proteins and sugars. Its primary function is water absorbtion. I don’t have the specific numbers on it, but it’s really not that hard to find molecules that can absorb hundreds of times their own weight in water. I’d imagine that’s in the ballpark.

My point was cold viruses spread through snot and direct contact with hands to mucus membranes (nose and eyes most notably). From “A cold virus is deposited into the front of the nasal passages by contaminated fingers or by droplets from coughs and sneezes. Small doses of virus are sufficient to produce infection. The virus is then transported to the back of the nose and onto the adenoid area by the nose itself!” Thus, washing your hands and using a snot rag to catch your drippings aid in slowing the spread of cold viruses. Sneezing fires out large and small bits of infected material, which is then largely further distributed by touch. Also from “From the time a cold virus enters the nose, it takes 8-12 hours for the viral reproductive cycle to be completed and for new cold virus to be released in nasal secretions. This interval is called the incubation period.”

Based on what I am reading about the cold, the idea of dry nasal membranes making you more susceptible is bunk. There is no evidence that dry air affects the moisture of your inner nasal tissues to any measurable degree. Again, I refer you to

The evidence appears to be that the symptom of snot is a way of spreading the virus much more than it is a bodily defense mechanism. Your body might THINK it is defending itself, but in fact it is just spreading the agent. Hence, the use of nasal decongestants to treat the symptoms do not extend the time of viral infection and provide some relief as well as slow the spread of the virus. The body uses mucus to defend the upper respiratory system from large and small contaminants … but cold viruses use this as a means of spreading themselves. At least, this is what I am gathering from the information I am reading.

I think you are daft on the order of magnitude needed to make slime. All the sites/photos showing hagfish do not show more than about a cup of the slimey stuff associated with the fish. In a bucket of water, I have no doubt it could make 5 gallons of dilute slime, but it is clear it is secreted by glands on the side of the “fish”.

To summarize, from what I gather, your body THINKS it is defending itself, but in fact it is spreading the virus. Mucus secretions are kicked into high gear by the irritative infection of the virus, which releases its progeny into the secretions. The secretions have no bearing on your recovery from the cold, and in fact, 25% of people infected with colds have no symptoms, but recover just the same. This point seems to have been missed in the article as well, but it is clear that the spread through nasal secretions is the primary motive of the virus.

Various hagfish slime links:

Includes a list of articles. Hagfish slime has fibers in it.
Summary of a Scientific American article on hagfish and slime. Secrets of the Slime Hag, by Frederic H. Martini; October 1998

A list of articles by this guy on hagfish slime research.
New Scientist article

Lots on slime, including link below.

Go read that page. This article is about the guy in the first link, David Fudge. It talks about the probable mechanism for slime expansion - and relates to human mucus membranes.
I think that pretty well answers the question about how much “stuff” is needed, and how it can quickly be ejected.

I have nothing more to add other than that “Various Hagfish Slime Links” would be a great name for a band.

Before I read the last couple of posts, I emailed Fudge. I typoed the email address the first time, so re-emailed the thing this morning (or I guess yesterday by now) when it was bumped back address unknown. When I got here I see you’ve found him on the web and a few more links besides. If he emails me back and has anything of interest, I’ll share.

Fudge got back to me with some info. Below find the text of his reply, and my email to him. I stand vindicated on my statement that the content of concentrate content had to be an order of magnitude less than someone’s estimate of 2 to 5% concentrate. I was wrong on my comparison to slug slime.

hi Fishhead,

there aren’t any good numbers published in the literature (yet) on the percentages of water, fibres, and mucus protein in naturally formed hagfish slime. some preliminary experiments that i’ve done suggest that the slime concentrate swells several hundred fold in volume when it hits seawater, and a typical hagfish has about 3% of its body weight on board as slime concentrate. that means a hag can quite easily produce a mass of slime that is many times the volume of its own body.

as for what happens to the slime, if left undisturbed in a large volume of water, the mucus part of the slime will eventually dissolve away, leaving nothing but a wispy 3-D web of fibers. if the slime is disturbed, then the fibres tend to coalesce and trap the mucus, forming a mat of fibres and mucus. eventually, though, the mucus will disperse and the fibers presumably are broken down by bacteria.

slug slime is very different from hagfish slime in that it is more concentrated, cohesive, and insoluble.

i hope this helps, and sorry for the long reply time. i’ve been away for several weeks.

-------- REPLY, Original message follows --------

Date: Saturday, 06-Jan-01 07:09 AM
To: Doug Fudge \ Internet: (

Subject: hagfish slime questions

Hi -

I got into a discussion of hagfish slime recently (odd thing, I know). Since I first saw a (less than 1 pound) hagfish turn a five gallon bucket of seawater into slime, I have wondered how the dickens they are able to do that. Seems like a huge drain on resources to me. If five gallons of seawater weighs about 44 pounds, and the proteins in the snot made up only one percent by weight of the resultant slime, the fish would be giving up 7 oz of protein (impossible, obviously, for a one pound fish) so the actual percentage of ingredients must be much lower. How much protein (and other important ingredients) does it take to make a given volume or weight of slime? How much slime can be produced by a single fish? Does this slime continue to grow and eventually dilute itself to nothingness, or does it reach a given size blob and stay at that size until it decomposes? I’ve seen pictures of hagfish traps with what looked like multiple ten foot long strings of slime hanging off them. Impressive, if you are into that sort of thing. I was interested in your description of the strings within the mucus. I made the guess (in mydiscussion/argument that precipitated this email) that terrestrial gastropods which use lots of slime probably used chemistry similar to that hagfish in order to produce the stuff efficiently. That supposition now seems largely in danger. Thanks for any light you are able to shine on this topic.



Ken Kesey’s novel “Sailor’s Song” has a cute bit of hagfish slime lore. He says if a hagfish produces so much slime it can’t swim, it will tie itself in a knot to wring off the excess. I can’t vouch for that fact-like bit. By the way, if that was contained in one of the many links supplied by Irishman, I apologize for not reading them all.