[Histonet] Hematoxylin Precipitate

[Bob Richmond]

The alum hematoxylins I've worked with required daily filtration. An
iridescent scum on top of the hematoxylin means you're overdue to filter.

When you brew a fresh batch of alum hematoxylin, it's a light yellow color.
As it oxidizes (slowly if you depend on atmospheric oxygen, instantly if
you add an oxidant such sodium iodate or mercuric oxide) it turns into deep
purple hematein (say hee-muh-TEE-in, not the same as hematin) which is what
you stain with. Hematein oxidizes further to filterable crud.

Whatman No.1 filter paper is fast and easy to get, and is usually
preferred. Sometimes Good Management Practice requires substituting a paper
towel, which works reasonably well.

You young whippersnappers shouldn't need to be told this by a 76 year old
pathologist!

Bob Richmond
Samurai Pathologist
Maryville TN