Paul Marshall when working at Chicago University did significant 
amount of work on dyes and staining, but not as significant as he 
did with Richard Horobin in Sheffield, I guess.
One of the things I remember with certainty was that he showed 
that Bismark Brown made NO contribution to the Papanicolaou 
stain.  At least, non that withstood robust chemical or physico-
chemical examination.

That does not mean that it makes no contribution in the eyes (read 
'mind') of the gynae cytologist!!!!

Unfortunately I cannot lay hand on his paper just now.


Russ Allison, 
Dental School
Cardiff
Wales