What is mouth pipetting

After all, they regularly use sophisticated pipette devices that are perfectly calibrated to move precise amounts of specimens from one vessel to another. Plus, the safety-conscious clinical laboratory professionals today may have a hard time comprehending a time when mouth pipetting was routine practice. In a photo typical of times long past, mouth pipetting is featured. Mae Melvin left. She is examining a collection of test tubes while her laboratory assistant mouth pipettes a culture to be added to these test tubes.

They recalled their misadventures with mouth pipetting—some humorous, some not—prior to the appearance of AIDs in All stopped when two chemistry technologists in Saskatchewan, Canada got hepatitis B from mouth pipetting quality control samples. No one could figure why he had so many positive VDRLs compared to the other students that rotated through serology.

Turns out he was using one pipette for a run of patients. Kathleen K. Maybe contributed to my mysteriously solid HepB immunity, with no disease. It actually tastes sweet. 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. 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. Army Biological Laboratories. In they wrote,.

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 s, 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. More precision. And before that, they had to mouth pipette But now, in a real lab, you get one of these babies and never look back.

Just what is mouth pipetting? 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.

Frustrated with trying to accurately pipette small volumes using the Carlsberg pipette which involved creating a fine glass tube, calibrating the tube with mercury or a dye, and then pipetting by mouth , Schnitger developed his first prototype not long after starting his postdoc.

Further tinkering led to the addition of a second spring to allow the piston to be moved past the measured volume to eject residual fluid from the pipette tip. This Gilson model, bought by Rainin Instruments just before the patent was issued, is the most direct ancestor of the Pipetman that you might find on your own bench today.

Regardless of who the first true inventor of the pipette was, there is no arguing that the pipette has become invaluable to modern molecular biology. The design has been tweaked over decades by scientists around the world, with additions made to make the device easier to handle while wearing gloves and the development of the multichannel pipette.

Much like scientific knowledge itself, the pipette has evolved through the work of researchers building upon the genius of those before them. Further Reading Duval, C. Francois Descroizilles, the inventor of volumetric analysis. Journal of Chemical Education, 28 10 , —