practicality

So, on the plane yesterday, I discovered that there's something wrong with my headphone jack that's making it cut certain frequencies, annoyingly right in the human vocal range. So as I couldn't watch tv on the plane, I went through some of my old files, finally ending up in a folder of documents and papers about Ebola and Marburg, as well as a somewhat randomly-included file on NIH's safety guidelines for a level 2 biohazard lab (random because Ebola and Marburg are level 4 - I didn't save the files in the folder, someone else did, I just kept them because they looked interesting).

And one of the things under the basic lab safety stuff is '4. Mouth pipetting is prohibited; mechanical pipetting devices are used'. This is also included in my chem lab rules, and it was included at least verbally in the lab rules for the plant physiology lab Yana and I were in, although it's not on the print copy. And this leads me to wonder - why anyone would ever think pipetting by mouth was a good idea, ever? Even if you're not using something horribly infectious or toxic, you run a decent risk of contaminating whatever it is you're pipetting with your own spit. I can see why it's included, but I dunno, seems like common sense to me.