Dead on arrival- Pus under the scope. 

We’ve all encountered pus on our bodies at one point on another. It usually occurs at a site of inflammation. It’s a whitish-yellow, viscous liquid.

So what’s inside the pus liquid?

Let’s find out.

Here’s a slide with a sample of pus.

Here’s a first look under the scope.

All those tiny cells are dead white blood cells (leukocytes). The irony is not lost on me, that in my previous post I was hunting for white blood cells, and here i have thousands of them – dead!

I also hoped to see some bacteria but couldn’t find any. I did find clusters of dead skin cells (i think?). However, no nucleus was observable in the cells – so it could just be an artifact.

I will hunt more carefully around and see if I can find any bacteria in this liquid. It smelled quite bad, so i am certain they are there – but again hidden from plain sight and need to be revealed.

In any case, the pus liquid made some nice patterns as it dried and here are a few. Even a seemingly disgusting and yucky liquid seems cannot help itself but obey the capillary forces..

5 Comments Add yours

  1. laksiyer says:

    Brilliant, absolutely brilliant. Pus thickens due to the DNA released by the WBC.. I remember that Staph aureus would secrete a DNase that would clear the pus so that the bacterium could spread.

  2. Manu Prakash says:

    @Saad: fantastic post. I am also wondering where the “yellow” color in pus comes from.

    @Laks: what a fascinating trick – pus is mostly DNA? And a DNAase to cut through it. Is this why pus has a protective role?

    What a bizarre world we live in..


  3. Saad Bhamla says:

    @laks – do you have any tricks (staining/dilution) to see bacteria in pus?

    I spent a few hours but didnt see any movements ..


  4. laksiyer says:

    Gram staining should work well Saad. If it is a Streptococcus infection, the bacteria can be tiny so use high power. @Manu, I didnt know until this moment that they had studied the structure of the released DNA, they apparently call it neutrophil extracellular traps. Extracellular DNA is now a hot field in bacteriology too.!

  5. Manu Prakash says:

    @laks: fascinating. Thanks for the paper links. I was thinking about this recent ameboa that also uses extra cellular DNA as the only example. It’s incredible that a lot of science discoveries is findings what we had forgotten yet again. I read a lot of news stories about this recent Nature Communications paper; and none of them cited the classic neutrophil paper.

    Can you imagine an abortion DNA dye (not the fluorescent yoyo dye) for labeling this extra cellular DNA.


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