Cough cough 

Do you know how many times you coughed today? Or sneezed.. And the days you don’t feel well or have a sore throat. It’s almost like an involuntary thing we just have to do to keep ourselves functioning well. Remarkably, a cough or sneeze is the very first behavior that ever evolved in multi-cellular animals
Yes, sponges can cough and sneeze. 

Last night, right after my dinner, I coughed. And coughed again. To a point that it was uncomfortable. And I pondered, why did mom always tell me to cover my cough and sneezes with my hand. Now, if you are an adult reading this – you will readily jump to the conclusion that cough and sneeze can carry germs, and you could give your germs to other people. Alright, I read that too as a child – but can you prove it. And can you prove it right now. 
I am thinking a lot about sanitation and hygiene as a global health problem these days. So it would be valuable to actually look (and be able to show readily to a person who does not cover up a cough or a sneeze) – what they are spraying everyone else. So let’s make this abstract idea of one person passing his/her germs to others – visible. Let’s begin. 

I took a simple clean glass slide. Now, since I wanted to capture particles coming out in my cough on a clean surface, I decided to clean this glass slide further by washing it in my kitchen sink with soap. I really cleaned it well and dryer it with a towel. 
An idea of control in science includes when you do the experiment in the null condition. Think of it as the before and after picture. So let’s take the before picture – I mounted my empty glass slide in my foldscope and at 140x magnification, I captured a simple blank image (look carefully – it’s almost blank with very tiny dust). 
Now was the big moment, and I just sat with the glass slide in my hand and waited and waited and waited for a natural cough. It was important for me to have a natural cough captured; since I know I could also force a cough. It’s as if my body was very well aware that it was being made a guinea pig and it would not cooperate. I was getting impatient, but soon after I coughed – and I positioned the glass slide right in the path of this explosion. 
Why do I call it an explosion. It sounds like one.. It actually looks like one. (Cite). It only takes around a 200 to 500 milli second (so half a second) but it releases probably thousands of tiny little things. Since Foldscope is excellent at deciphering tiny little things – I was quick to put the slide in my foldscope and watch the saga unfold. 
What I saw was really amazing.

  I saw all kids of debris, microscopic salivary droplets (as small as 10 microns), tiny bacteria and particles and crystals of strange shape and form and finally – my own epithelial cells (the wonderful cells that line up almost all organs of our body). What? I was coughing my own cells out. So off course this is a path for disease transmission – since I am just spraying around all my tiny little bits. 
I was incredibly excited to see the intact cells. Although almost a tiny little rocket launch – the cells seemed to have survived the journey. Viability is crucial for some diseases. In a split second; a cell that was happily attached or swimming in saliva lands on another substrate, on a foreign body. 


My biggest surprise was these tiny little needle like crystals. I don’t know what they are; but they are beautiful. Please comment below if you have a theory about the same. Lots of other little bits and pieces, dead shreds. 


Finally, as the saliva droplets start to evaporate; I see crystal formation. They are quiet incredible too. 

Now, I sincerely hope you will repeat this experiment and share what else are you coughing out. And as always, remember what your mother used to tell you; always cover up your cough or sneeze. You don’t want to be the one transferring your germs to other.. 

Other fun cough and sneeze puzzles: 
1) Fluid dynamics of coughing and sneezing:


4 Comments Add yours

  1. laksiyer says:

    Wonder what the needles are. Will repeat and try– the cough and cold season is on its way soon anyways 🙂

  2. Manu Prakash says:

    @Laks: Yes; I am really perplexed with needles coming out of my mouth. I have become a needle breathing Nija. On a serious note; its crystallin in it’s form.

    In case it matters; I had chicken tikka masala a few minutes before the cough started 🙂


  3. Manu Prakash says:

    Just heard back from a doctor friend with one hypothesis. See below.

    “The crystals are most likely Charcot-Leyden crystals. They are often seen in the sputum of allergic individuals. Do you have allergies?

    Now; this is getting interesting since I am not aware of me having asthma symptoms.

    Wikipedia: ” Charcot–Leyden crystals are microscopic crystals found in people who have allergic diseases such as asthma or parasitic infections such as parasitic pneumonia or ascariasis.”

    I will run this experiment several times now; to see these crystals at higher mag using the 450x lens. I will also upload Ara in polarization mode. I got some work cut out for me.

    The mystery thickens.


  4. laksiyer says:

    Fascinating what we can learn about ourselves. Wonder if these crystals are amenable to staining. I think I will start coughing onto slides for the before and wait for the cold season for the after.

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