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Comment by Metacelsus | Hacker News Reader

Author here. I'm happy to answer any questions.

Thanks! My daughter works with pipettes all day long, and this is fascinating. One of her favorite aphorisms is "Don't lick the science!" and today I learned that apparently we used to lick the science.

Even today mouth pipettes are still used occasionally (in embryology, for example).

I use a mouth pipette (really just a small piece of glass and some rubber tubing with a filter to transfer tardigrades to my microscope slide. This was recommended to me by a tardigrade expert. I had previously used bulb for large glass pipette (my high school lab had a big sign "DO NOT PIPETTE BY MOUTH") and micropipettes for decades, and I was blown away with the level of control you get from mouth pipetting. I'm not that bothered by inhaling some tardigrades.

But being lazy one of my side projects is to make an automatical tardigrade pipettor (ML-based with motors and stuff).

I am surprised there is on mention of rubber bulbs. If the main concern is safety, as the beginning of the article seems to imply, the rubber bulb would have been enough of a solution. The micropipette solves mostly all the other concerns: speed, repeatability, avoidance of contamination, ease of use one-handed. A great invention for sure. Why would they even mouth pipette if they can use a rubber bulb? Is it that the rubber bulb was somehow invented later? Did you encounter anything about that when researching this topic?

it's all about control. You get a lot more feedback and accuracy with your mouth.

OK, I see. I still find that surprising because I would imagine having the pipette hanging from your mouth doesn't allow ou to really see what is going on if you are really trying to hit a target volume. I would have thought the feedback you need is visual.

Oh. I'm actually looking at the pipette tip under a microscope (in my case it's clear glass that I pulled to a fine tip using heat) and I can see the tardigrade get sucked into the tip when I gently pull with my mouth. And then I can see it whoosh back out when I push. The actual volume doesn't matter, just that I pick a single tardigrade and place it where it needs to go.

The other folks pipetting by mouth are actually looking down at the tube and see the fluid volume reaches a particular well-defined line on the glass pipette. If you can taste the fluid, you've gone too far.

I just looked up photos of people pipetting by mouth. They use tubes.

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