Aidan Schurr in Lower Hutt, New Zealand asks:

>>Have an obscure request for a MacCallum - Goodpasture method for Gram 
positive and negative bacteria. My question: what is the significance of the 
aniline called for in this method? (both in the staining solution and in the 
differentiator).<<

Man, I'll say that's an obscure request. I have no idea what the aniline is 
for.

This method was still in use by some of the ivy-covered professors in the 
ivy-covered halls of Johns Hopkins when I was a resident there around 1965. 
MacCallum was the chair of pathology there until his sudden death about 1942, 
and Goodpasture (of acute glomerulonephritis with pulmonary hemorrhage fame) 
did his work there in the 1930's.

It's a gorgeous stain for fibrin, but no more reliable a bacterial stain than 
the Brown and Brenn (in many variants) that was in the process of replacing 
it in 1965. Tissue Gram stains are of much less diagnostic value than most 
pathologists believe (usually a non-specific thiazine dye stain such as 
toluidine blue is simpler and finds bacteria better), and I see no reason to 
perform this obsolete procedure in the new century.

Bob Richmond
Samurai Pathologist
Knoxville TN