[Histonet] at a troubleshooting loss

[John Kiernan]

Others have suggested graphite dust from pencil "lead". I've also
seen little bits of ground glass, from writing on slides with a
diamond pencil.
 
Another contaminant that we used to get several years ago was 
dark brown fungal spores, singly or in clusters about the size 
of a cell's nucleus. 
 
Probably the spores came from the building's air 
ducts (which at the time were lined by mildew several mm thick), 
and settled on slides that were on the hotplate, waiting to be dewaxed 
and stained. These spores must have had a strong affinity for tissue 
because nothing would wash them off.
 
John Kiernan
Anatomy, UWO
London, Canada
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----- From original Message -----
From: Michele Wich mwich <@t> 7thwavelabs.com
> And secondly, aside from formalin, are there any other common 
> agents of
> blackish pigment in H & E staining? (The artifact appears on the 
> slidesboth on and around the tissues.) 
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