Suck It: The Ins and Outs of Mouth Pipetting


If you ever find yourself working in an infectious disease laboratory, whether it’s of the diagnostic or research variety, the overarching goal is not to put any microbes in your eye, an open wound or your mouth. Easy enough, right? Wear gloves, maybe goggles, work in fume hoods and don’t mouth pipette. When working with pathogenic bacteria and viruses, priority number one is Do Not Self-Inoculate.

This is obvious for anyone who has worked in a shiny biology or chemistry lab or seen an episode of CSI: Crime Scene Investigation (we’re all friends here, just admit it), but one of the most commonly used pieces of equipment in labs prior to the 1970s was the leading cause of laboratory-derived infections: the honorable pipette. How could that be possible, you ask? By using one’s oral cavity with the pipette to measure and transfer liquids.

Today our manual pipettes are rather sophisticated, plastic-y devices perfectly calibrated for moving precisely exact milliliters, microliters and picoliters of valuable solution from one vessel to another, whether it’s of a urine sample, some spare radioactive material you have lying about or toxic solvents. But before the development of cheap mechanical pipettes in the ’70s, using your mouth to pipette solutions was more than a common sight, it was a way of the lab.

Former Centers for Disease Control (CDC) parasitologist, Dr. Mae Melvin (Lt), examines a collection of test tubes while her laboratory assistant mouth pipettes a culture to be added to these test tubes. Source: David Senser/CDC.

Don’t worry, reader, I heard you tentatively whisper, “just what exactly is mouth pipetting, dare I ask?”

Like so: insert an open-ended glass capillary tube into your mouth. Place the opposite, tapered end of the tube into a solution of your choice. Microbial stews, blood, cell culture, it is totally your call. With a method that carefully mimics the sucking of a straw, draw a solution upwards through your man-made pipette to your desired volume using the tension created by the reduced air pressure – yes, suction! Maintain the tension with your mouth. Do not suck too hard and inadvertently slurp the solution into your mouth. Careful now. Gently move the pipette end from one vessel and release your precious cargo into yet another vessel.

That is mouth pipetting.

A wonderful demonstration of mouth pipetting by Dr. Armand Frappier, a microbiologist and expert on tuberculosis. Look closely: you can see him draw a dark liquid slowly towards his mouth. What could it be? Soda, a culture of TB, serum for cell cultures? You can watch the entire video clip that this GIF is based upon here. Source: Musée Armand Frapper.

The sparsity of history on pipetting techniques (itself a shocking shortcoming, I’m sure you’ll agree), forbids us from generalizing the prevalence of this phenomena. But we do know that it was the source of a ridiculous number of accidents, whether swallowing a corrosive or toxic substance or an infection with one’s research material  (1). A survey of 57 labs in 1915 found that 47 infections  were associated with workplace practices and more than 40% of those were attributed to the practice of mouth pipetting. A longitudinal study of 921 workplace laboratory infections from 1893 and 1950 found that 17% were due to “oral aspiration through pipettes or to splashes of culture fluids into the mouth (2).”

Infection through the use of one’s oral cavity was such an occupational hazard that it warranted an article, “The Hazards of Mouth Pipetting,” from two gentleman working for the U.S. Army Biological Laboratories. In 1966 they wrote,

although the use of pipettes in the early chemistry laboratories undoubtedly led to accidental aspiration of undesirable toxic and poisonous substances, the first recorded laboratory infection due to mouth pipetting occurred in 1893 … [with] the case of a physician who accidentally sucked a culture of typhoid bacilli into his mouth …

compared with the equipment and procedures required to avoid other types of microbiological laboratory hazards, the method of avoiding pipetting hazards is so elementary, so simple, and so well-recognized that it seems redundant to mention it [emphasis added by author]. However, continued accidents and infections in laboratories illustrate, even today, that there is a lack of acceptance of the simple precautionary measured needed (2).

By the 1970s, mouth pipetting had fallen out of favor as swanky, mechanically adjustable and cheap pipettes flooded the market (3). They were not only infinitely safer but also far more accurate. Instead of drawing a semi-approximate volume of solution with the imperfect measuring device that is your mouth, standardized and calibrated pipettes were available that could zip up a solution to one’s desired volume. More precision. Better experimental results. Less contamination. More ergonomic. Fewer infections. Nowadays, mouth pipetting is explicitly banned from laboratories.

A woman mouth pipetting to select specimens of ectoparasites. Source: National Library of Medicine

And, indeed, you might think that this old school technique is thankfully old news and good for a giggle but mouth pipetting is still practiced in some countries. A study looking at the lab practices and biosafety measures of Pakistani lab technicians found that mouth pipetting was reported by 28.3% technicians (4). This paper was published just last year, in August of 2012. Another study in 2008 found that Nigerian technicians working in clinical laboratories were not only improperly vaccinated against many of the preventable diseases that they were testing for (!) as well as eating and drinking in the lab but 1 in 10 also reported mouth pipetting (5).

Lest you think this is just happening in developing countries, be rest assured that American teenagers and young adults will always find a creative way to  jeopardize their health. In 1998, a 19-year-old nursing student in Pennsylvania was  hospitalized for several days following infection with a unique strain of Salmonella paratyphi she was working with in a lab; the case report strongly suggests that mouth pipetting was the culprit behind this particular microbial misadventure (6).

Another article from 1995 assessing lab accidents found that 13% of laboratory-acquired infections were a result of mouth pipetting. That’s 92 accidents attributed to someone in a lab deliberately putting a pipette or capillary tube into their mouth and sucking up some solution laden with microbes (7). Clearly, we still have a way to go in dissuading people to stop using pipettes as straws.

A techician mouth-pipetitng environmental water samples in Malta. Image: E Mandelmann. Source: History of Medicine

A technician mouth pipetting environmental water samples in Malta. Image: E Mandelmann. Source: History of Medicine

Mechanical manual pipettes have been a godsend to technology and the sciences, saving researchers time and resources in measuring and transferring liquids. Pipettes now serve as an icon of the scientific pursuit of knowledge – we’re all familiar with the close up of the gloved hand and pipette tip hovering over some glowing liquid. It’s banal, efficient and ubiquitous. It’s the dogged, unsung hero of the lab but there were several decades when our method of pipetting was also a microbial misadventure in the waiting.


“There are reports of laboratory infections by means of the pipette with quite a variety of microorganisms. In the intestinal group: typhoid, Shigella, salmonella, cholera; among others, anthrax, brucella, diphtheria, hemophilus iniluenzae, leptothrix, meningococcus, Streptococcus, syphilis, tularemia; among viruses, mumps, Coxsackie virus, viral hepatitis, Venezuelan equine encephalitis, chikungunya, and scrub typhus.” Download this neat article on the history and epidemiology of lab-acquired infections here.

Want to see more pictures of mouth pipetting? Of course you do! I’ve been collecting them on the Body Horrors tumblr here, here, here, here and here. Here’s a sign. And here’s a riff on a meme.


1) AG Wedum. (1997) History and epidemiology of laboratory-acquired infections. J Am Bio Safety Assc. 2(1): 12-29

2) Phillips GB &Bailey SP (1966) Hazards of mouth pipetting. Am J Med Technol. 32(2): 127-9

3) JA Martin (April 13, 2001) The Art of the Pipette BiomedNet Magazine100

4) S Nasim et al (2012) Biosafety perspective of clinical laboratory workers: a profile of Pakistan. J Infect Dev Ctries. 6(8): 611-9

5) FO Omokhodion (1998) Health and safety in clinical laboratory practice in Ibadan, Nigeria. Afr J Med Med Sci. 27(3-4): 201-4

6)B Boyer et al (1998) The microbiology “unknown” misadventure. Am J Infect Control. 26(3):355-8

7) DL Sewel (1995) Laboratory-Associated Infections and Biosafety. Clin Micro Rev. 8(3): 389-405
HILL, N. (1999). Laboratory-acquired Infections: History, Incidence, Causes and Preventions, 4th edition. Eds. C. H. Collins and D. A. Kennedy. Butterworth Heinemann, Oxford 1999. Pp. 324. ISBN 0 7506 4023 5. Epidemiology and Infection, 123 (1), 181-181 DOI: 10.1017/S0950268899002514

73 comments on “Suck It: The Ins and Outs of Mouth Pipetting

  1. BioBlubb says:

    There is one thing I really don’t get. I’m pretty sure even back in the days some sort of tubing must have been available! Why not put that between the microbial soup And ones mouth?! Is that so far-fetched? Not only would you NOT risk your life, but you had the additional benefit of actually seeing the graduation marks…

    • Trudi Allen says:

      You could not use tubing if you were pipetting blood for ESR tests. You had to put the end of your pipette into the sample, suck it up to about the mark (hoping that there wasn’t a clot or a small sample so you got an air pocket, which meant the blood shot straight up the pipette), then you had to quickly put your finger over the top, lower the blood level to the mark, and leave the pipette vertical in the holder between the rubber seals for 1 hour for the ESR test. I got many a mouthful of blood in my early days as a lab technician in Haematology.

  2. D: Out of all the articles I’ve read on the site, this is the one that makes me cringe the most!

  3. Neuroskeptic says:

    When I was at school, we used manual pipettes in chemistry lessons. But when our teacher wanted to get some pipetting done quickly, he’d just suck on the tube. He always said: “Don’t ever do this yourself, but it’s the fastest way…”

    • bodyhorrors says:

      I feel like chemistry professors are always living on the edge and a bit thrill seeking. This is a great story, thanks for sharing! I love hearing from other people about their experiences with mouth pipetting or second-hand stories.

  4. Frank Norman says:

    The MRC Insight blog recently published an old photo of mouth pipetting in a flu lab:

    • bodyhorrors says:

      Hey thanks Frank! It’s a wonderful picture with a great story. I’ve thrown it up on the Body Horrors tumblr with other images of mouth pipetting. Thanks for visiting!

  5. Briouat says:

    … in my former lab, some tech still used it (2009)
    an E. coli lab, with O157:H7 and other friends
    that’s the way she learned it, and she never had any problem … so why would she change ?

  6. Gah- how are people not dissuaded by the ick factor of sucking a bacterial culture up a straw? I don’t get how it could be faster either, as you suck and release to get the right volume- unless you’re a learned master of diaphragm control? Oy.

    • bodyhorrors says:

      It’s a true art, Patricia, requiring incredible concentration and skill! It’s not just bacteria either; I have read stories of people sucking up acidic solvents and burning their mouths. If you visit the Body Horrors tumblr, you can see two young women mouth pipetting bromine and H2S04, otherwise known as sulfuric acid! Check out their pictures here and here. Oy, indeed!

  7. Insect Aspiratee says:

    Mouth aspirators aren’t just limited to liquid handling, I use one to move insects around. At least mine has got a filter in it.

    • bodyhorrors says:

      That’s right! In one of the photos in the article, there is a lab technician moving ectoparasites and many people working in entomology use mouth pipetting to move mosquitos and other little buggies. Generally safe, if you have a little cotton plugging the mouth end or some sort of filter. And everyone’s eaten bugs before, right?, so what’s a little mishap every now and then …

      • Insect Aspiratee says:

        Well . . . they’re also used for collecting blood-sucking insects to monitor for infections e.g. mosquitoes and malaria, and probably a lot of those are ‘lab-made’ and don’t have a filter, so it can be dangerous.

      • bodyhorrors says:

        That’s true. However, that’s only if they’re bitten. In the mouth. But take the case of mosquitos+malaria: cases of mosquito-borne infections from swallowing a mosquito are unheard of in the medical literature. If you swallow a mosquito containing the sporozoites of the malarial parasite, it is more than likely your stomach acids will take care of the parasite. The sporozoite needs to enter the bloodstream directly to cause malaria.

  8. jessica says:

    I was trained to mouth pipet in the late 80s and early 90s but reserved it for harmless solutions – and we were strict about the harmlessness. This was back when we were using both those green mechanical pipetors (with the little thumb wheel) and the red or black bulbs that couldn’t actually suck up more than about 15ml. This was also back when disposable pipets were unusual and we spent a lot of time cleaning out glass pipets. With the advent of the electric pipetor, the switch away from mouth pipetting made so much sense sense. And when good cordless models became available, there was no reason at all to mouth pipet. That said, I could always resuspend a (non-pathogenic) bacterial pellet faster by mouth pipetting than using an electric pipetor.

    Mouth pipetting, once you were expert, was actually extremely precise. If you want to see how it works, try mouth pipetting with disposable sterile pipets and clean water.

    • That was me too! I was actually more cautious about mouth-pipetting than many of my lab mates, but I definitely used the technique sometimes. It was so much faster than those pipette bulbs!

  9. kjflynn06 says:

    I went to a liberal arts school with a lot of international students. A Croatian girl was caught mouth pipetting some serious inorganic chemicals… almost worse than O157:H7!

  10. […] Senate Delivers a Devastating Blow to the Integrity of the Scientific Process at the National Science Foundation (first they came for the political scientists?) Watch these giant deep-sea isopods go about their day (awesome video) Natural History in the -omics era Why Total Reporting of Genetic Results Is a Bad Idea Suck It: The Ins and Outs of Mouth Pipetting […]

  11. drjuliebug says:

    An old friend described mouth-pipetting misadventures in a biochem class circa 1974 this way: “We were working with homogenized rat intestinal tissue. If you swallowed some, you were in the Colon Club. If you got it in your mouth but managed to spit it out, you were in the Semicolon Club.”

  12. E. Manhattan says:

    My mom was a chemist – during World War II, while working in the lab, her assistant handed her a smaller volume pipette than she had asked for, and Mom ended up with acid in her mouth. She lost most of her taste buds permanently.

    • bodyhorrors says:

      Oh my! Your poor mother! While doing the research for this article I read of a good number of documented cases of siphoning up corrosive and acidic solutions. The horror. Thank you so much for visiting and sharing, E. Manhattan!

  13. Hahaha, while working in a Behavioral Neuroscience lab I accidentally squirted KXA (Ketamine, Xylazine and Acepromazine) into my eye during neurosurgery. Needless to say, things started to become very strange and I aborted the surgery. Love the post!

  14. How in the world did everyone not get ill after mouth pipetting? What a informative and well written post. Congrats on being freshly pressed and thanks for sharing. Angelia @

  15. segmation says:

    Thank you for sharing about pipetting. I have never thought about this before.

  16. I used to work as an Electroplater and I have mouth pipetted sulfuric, hydrochloric and nitric acids. Yay me!

  17. soccerbrain says:

    I worked in a wastewater analysis lab (sewage, effluent, and that gunk) my boss swore by mouth pipetting. And then he just swore when he inhaled nitric acid. I admit I picked up the bad habit, but quit after I got brewery effluent in my mouth (at least it was beery and not something worse).

  18. Huffygirl says:

    I remember mouth pippetting and the fact that nobody thought it was odd or dangerous at the time. Looking back on it now many years later, I now wonder “what the hell was WRONG with us that we thought this was a normal and good idea?” Glad to see this bit of scientific nostalgia and congratulations for the elusive FP.

  19. rejdelacruz says:

    We are blessed nowadays for we have aspirators in the laboratory!

  20. machhapuchhre says:

    Fascinating, it bet there are lots of science horror stories that still happen around the world

  21. Hi! I’m just glad that mouth pipetting and pipe sucking has been confined to the neighbourhood chavs and lay-by languishers that used this tried & tested mechanism to steal petrol & diesel! I may just add some micro bacteria to my tank next time I refuel to ensure a more tasty mouthful! Great article!

  22. pickledwings says:

    Great article, the whole idea of mouth pipetting has given me the creeps since a video my class was shown in sex-ed class back in the mid 80s.

    The video clip was aimed at the girls but was shown to the whole class. It was about the importance of regular pap smears and there was this scene of a gynecologist taking a sample of a woman’s vaginal fluid through a mouth pipette.

    Of course the whole class cringed at that scene, not just because we were a bunch of immature teenagers, but also because the mid 80s was also the time of massive AIDS paranoia.

    For as long as the practice of mouth pipetting was around, how on earth could someone not have developed a mouthpiece with a trap or some sort of air permeable dam device in it to protect both the technician and their sample from contaminating each other?

  23. miniwatsa says:

    This is a terrific post. Funny and informative at the same time. When I was in highschool in India, believe it or not, we definitely used our mouths to pipette everything in chemistry lab. Hilarity ensued, and I think I’ve blocked the bad memories!

  24. DNamto says:

    Well written, it made me remind of you school days me struggling with buret and pipet. 🙂

  25. omchakrasauras says:

    Interesting post. I found the information to be informative and written clearly and concisely. Thank-you for sharing. Sat Nam. Namaste.

  26. M.A.M says:

    Compelling, but gross just the same!

  27. whysamiam says:

    Wow! How dangerous!! But I guess it has its pros and definite cons.. Great blog! Sam

  28. Britt says:

    So happy to see a real bench scientist on Freshly Pressed! This brought back memories. When I was a grad student I scolded an elderly (and quite famous) hematologist who was collaborating wtih us. He was mouth pipetting blood (blech) with malaria (!). We’ve all done stupid things in the lab, but it’s funny that this gross and dangerous technique persists. Of course, this is all very well written and researched and yay, you!!

  29. pumarode says:

    We have come a REALLY long way. Pipettes are very sophisticated nowadays. I remember starting college in the chemistry lab. When I saw DO NOT PIPETTE BY MOUTH, I honestly thought it was a metaphor. Then I would self consciously try not to breath (I guess ok around harsh chemicals and bacteria). Now I know why the TA was laughing at me!

  30. xdanigirl says:

    Oh my gosh!! This is just craziness!!
    This was a great piece! Congrats on being Freshly Pressed!

  31. As a certified medical technologist who studied in the late 80’s….I did mouth pipette from time to time because the bulbs used for pipettes back then would siphon up the liquid and but often lost suction just as you attempted to move the pipette from the original source to the petri dish or test tube where you wanted to transfer the liquid. When you are working with a very tiny sample that was also likely hard to get in the first place, you don’t want those kind of mishaps. If you call a doctor one time to tell them you wasted the sample….you won’t do it again. Using my finger on top of the pipette to assure the liquid would remain in the pipette until I was ready for it to be dispensed is what lead me to mouth pipet from time to time – and into the 90’s.

    The pipets of today are amazingly precise and even fun to use. I’ve used a pipet that can dispense up to 20 aliquots at a time and of only 10 microliters! It is fun to reflect on how things change.

  32. heronwheels says:

    I’ve been working in a clinical laboratory for 15 years, many of the techs are 30+ year veterans and talk fondly of mouth pipetting (even while mentioning the mouthfuls of urine they would occasionally suck up). I’m definitely glad the practice has fizzled out (at least in our lab), I think I’ll stick with a mechanical pipette 🙂 Great post!

  33. georgialena says:

    One day in my first year of undergraduate science, we were in our chemistry lab and I witnessed two students happily using the plastic pipettes to pick up water from a beaker and then squirting the water into each other’s mouths. They got thrown out.

  34. msharyf says:

    Mouth pipetting is still practiced in biochemistry laboratories in Srilanka and India. I should know. I’ve had to do that myself in university. and yes I did get some chemicals in my mouth too. :s

  35. Sofia says:

    It’s so fascinating! I studied pharmacy and never went into any fields of being a lab investigator/ microbiology / etc.. (anything to do with pipetting) But I remember when I was studying I found all this sucking pipette thing a bit perplexing and always wondered if people had accidents with dangerous liquids coming unto their mouth. Now you’ve answered my doubts 🙂

  36. Oh My Gosh!!! I actually left my Biochem/Mol. Bio PH.D. program because I was told by my doctoral advisor that mouth pipetting was still considered the most accurate way to measure!!!! This was in 2004! (It wasn’t the only reason I left the program however it made it so much easier to go!) Thank you for confirming how disgusting a practice that really is…

  37. I spent many a year mouth-pipetting in an infectious disease lab. Fortunately no accidents AND we did have those filters at the mouthpiece end. 😉 Thanks for taking me down memory lane. Now if you want to cringe, you can do another piece on radioactivity.

  38. Dejan says:

    I have much mouth-pipetting experience, including with some of the nastier common chemicals (such as NaOH or HCl). I can only say it is a good thing I don’t do any lab work these days.

  39. Ah, I remember these. Everyone in my class got a mouthful of KMnO4 and K2Cr2O7 at least once during the first lab year. Me? Not so much for following tradition. I accidentally swallowed Mohr’s salt and choked on it, lol. =P

  40. The one and only time I ever used a mouth pipette was during work experience back in the mid-80s. I ended up with a mouthful of a blue chemical (no idea what it was actually but I don’t think it was anything dangerous). I just rinsed my mouth out and carried on. After 28 years, I still clearly remember the taste and the feeling of panic. Don’t think I could have done it with some of the infectious / gooey substances that others have described. Eeuww!!

  41. sedrate says:

    When I started working at the lab, the senior tech was about to retire. He was sharing stories of mouth pipetting with the other older techs. One time, he sucked up a mouthful of Hep B contaminated blood. He rinsed and prayed like one possessed and luckily tested negative. Getting jabbed with a contaminated needle is an occupational hazard, I once body slammed a patient to the floor who had dropped her urine sample container into the biohazard waste bucket’s narrow opening and was reaching in to retrieve it. Strangely I did not get into trouble for that…no sense in asking for extra trouble by sticking something in your mouth.

  42. sedrate says:

    PS- I’ve been looking for a well written lab blog for a year now, congratulations on being Freshly Pressed!

  43. nickmenard says:

    I am glad that my school was able to have the ones with the squeeze bulb! I feel like it wasn’t the safest thing for those people to do! But I guess if you love what you do, you will do anything for it!

  44. mrnhecita says:

    Experienced mouth pipetting when I was college too(2004).Luckily it was just for the feel of how they do it in the past. We used a rubber tubing connected to the pipet and water as specimen though. During our internship we made use of syringes to produce the suction force needed to make the fluid rise in the pipet.

  45. lissajuliana says:

    Not exactly mouth pipetting, but this reminds of stopping for gas in a very rural area of Mexico. There was a sign for a gas station, but not pumps in sight. Instead, a man came out with a gas can and a tube. He used his mouth to suck the gas up to the top of the tube, capped it with a thumb, put the tube in the tank and raised the can. Worked of course, but can’t possibly be good for you on a regular basis.

  46. I had no idea that such folly was regular practice! Nor do I have any idea, how I ended up reading an article about something as random as “Pipetting” in the first place… ok I’ll admit it, your racy title brought out the curious little boy in me.

    For some reason it reminds me of that great youtube video where they use radioactive material and geiger counters to sell make-up remover:

    “Horrible science” for adults! You write with real life and vitality. This was an education. Thankyou.

  47. fattorina says:

    God I would never mouth pipette. The thought of sucking something up terrifies me. Saw someone mouth pipetting once and was in absolute shock.

  48. jerrirambles says:

    I never thought I’d find a reason to love my handheld pipette that much more but UGH that is just nightmarish! Thanks for the lesson on this, I’ve never heard of this.

  49. Lab Rat says:

    Reblogged this on Lab Rat News and commented:
    The history of my profession….evolution of the job as it were.

  50. OyiaBrown says:

    Reblogged this on Oyia Brown.

  51. They still use the pipette in hospitals in Ukraine ….



  52. triwriter45 says:

    I am a medical technologist in a public health microbiology lab. I am young enough that I didn’t learn to mouth pipette – but I still managed inoculate myself with something quite deadly! We become casual when procedures become routine. The same with pipetting. It was faster and more convenient to use the mouth – and nothing bad has happened yet, so…
    Great blog

  53. Ann Pimblott says:

    I am from England, I started to work in 1973 in a research laboratory and did chemical analysis. I used a mouth pipette every day of the week for 2 years, pipetting hydrochloric acid and sulphuric acid and often got a mouth full. Never thought any thing about it until I read this blog.

  54. microbegeek says:

    Hey, really enjoyed reading this, and it’s mind blowing that automated pipettes weren’t developed earlier. I’m myself working in environmental microbiology and for that matter I never really know what I’m dealing with beforehands. However, I found myself mouthpipetting a couple of times now, as despite the efficiency and accuracy of automated pipettes, there is one thing they just cannot do. When I had to pick single cells of diatoms (hard shelled algae) or, during my studies oocytes, for transfer you want them in as little volume as possible, there is almost no way around mouth pipetting, given the nature of the object you want to “suck up”. However, this is the limitation already, I’m only talking of capturing small objects in liquid into a capillary moving around under your microscope (always using a sterile filter somewhere in the tubing though, I’m not stupid). I haven’t yet found a pipette or device that could do that. At least not, if you can’t afford to invest in micromanipulators solely build for that like the ones found in IVF facilities. But let me know if you would have an idea.

  55. createdbyrcw says:

    Long-time mouth pipettor back in the day…best (worst) moment was doling out a ton of bacterial broth into tubes using a 25 mL pipette for several minutes and then transfering bacterial cultures using a 1 mL pipette.
    After about a dozen or so sucks on the 25 mL, I wasn’t paying enough attention and did a 25-mL suck on the 1 mL pipette…almost inhaled the cotton ball and got a good mouthful of bacterial culture. Salty and a little yeasty.
    Luckily, I worked in a bacteriophage lab, so all of our bacterial strains were very well attenuated…no harm, no foul, and maybe just a titch more careful (for a few hours, anyways).
    Thanks for the post…it brought back memories.

  56. That is wild information! Never in my entire life in the lab did I imagine mouth pipetting! Great article. I will have to share this to my students! Thanks, btw.

  57. smistupot says:

    Thank you FP for such a great article.I worked in a university teaching hospital in the 1970’s in Blood Transfusion.There it was common for 2 of us to x/match at the same bench with our reagents on a cold tray between us.At that time we mouth pipetted saline to make up our working solution of in house AHG.It was then that the 2 of us (blokes) developed IM (glandular fever) He was courting at the time and I had been married for several years, therefore I blamed him for the contagious disease. At my age at the time it was something I wouldnt wish upon my worst enemy.I do know that mouth pipetting does still gone on in some labs and even a colleague of mine blames the loss of some teeth on this practice.!!!

  58. John says:

    BioBlubb kicked off by saying surely tubing was available. In the 60s I saw the Senior Technician use tubing between his mouth and the capillary pipette when taking blood from babies’ fingers, but in this case precise measurement was not required and it would not have been possible. The rubber fillers suffered from a simlar problem, and for some years, until I was in a situation when repeating pipettes were accurate enough for my needs, I would use the rubber pipette filler to take the liquid well above the mark, then, rather than trust the rubber mechanism to hold the liquid reliably, quickly remove it and quickly substitute my finger, using it as in mouth pipetting – Normally I didn’t have to repeat the procedure more than once or twice before I got it right.
    Getting acid in your mouth gives the term “Molar Solution” a totally new meaning! But strangely, people who eschew mouth pipetting acid will still drink things like Coke or Pepsi.

  59. E O'Brien says:

    We still use glass volumetric pipettes as they give better precision for volumes over 1ml. automated pipettes for 10, 15, 20, 25 ,50 ml are not good for accurate preparation of calibrators. We stopped all mouth pipetting following the Howie report, we use the blue/green/red plastic filling devices to fill the pipette, but it is much easier to regulate the level pre dispense with a finger. At school (1968) we mouth pipetted, you learnt to watch what you were doing.

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