Mucus

Mucus is what lines your mucous membranes, just as phosphorus is the element which makes compounds phosphorous. It is a simple rule — the -us ending is normally a noun; the -ous ending is normally an adjective. A person who uses the word 'humerous' is referring to something about, of, or related to the humerus.

That said, I was mulling over the colours of mucus. I am quite sure it would make a perfect artistic medium if it wasn't normally full of the plagues of humanity.

Clear, colourless mucus is the norm. I've seen yellowish mucus, which indicates contaminants, perhaps infection; brown mucus, the darker variant, almost certainly means infection. Green mucus, the greyish-green iron(II)-coloured variety, is pretty serious. Mucus with red streaks is often the product of coughing or sneezing too violently; if you have dark red clots in it, this is probably either life-threatening or indicative of some sort of nosebleed.

I've seen brown mucus from heavy coffee-drinkers which simply meant that they hadn't washed out their mouths after drinking. I've also seen wine-coloured sputum from other drinkers.

Why did I think of all this? Why am I writing about it? It's a long story.

I was actually thinking about my students' writing skills and how irked I was with their inability to spell phlegm or phosphorus correctly. Bad pH readings, I suppose.