Dear Russ,
    How important is the fixation in the MGP stain?  I have one researcher from Egypt here requesting the stain, but his tissue is all fixed in NBF.  Also, how important is the tertiary butanol?  Can n-butanol be used instead?   I found some very interesting comments in "Animal Tissue Techniques" by Gretchen Humason, 2nd Ed. page 277.  She sited a MGP stain procedure by Kurnick, 1952 were he used n-butanol to differentiate the methyl green, left the pyronin out of the first stain solution and made the pyronin a separate step after the methyl green.  The pyronin was saturated in acetone.  Any thoughts on this?
  What is the title of John's book you sited?
Many thanks,

Sarah Christo, HT (ASCP)
Texas A&M University
College of Veterinary Medicine
Dept. of Vet. Anatomy & Public Health
College Station, TX  77868-4458
schristo@cvm.tamu.edu

>>> RUSS ALLISON <Allison@cardiff.ac.uk> 07/28 7:51 AM >>>
The comments on "cleaning" methyl green are wellvery well made.

One comment to add - it IS possible to purchase pure methyl green.  
Merck sell it and the BSC certify it.  Hans Lyon did find that it was 
not always pure or even methyl green.  What he found on examination 
was that it could sometimes be, or be contaminated by, ethyl green.
Importantly, it made no difference to performance (in MGP 
staining), whether it was methyl or ethyl.

As has been so well described in earlier correspondence, it is the 
oxidation product that causes the problem.

I think it is Barka & Anderson's book - Histochemistry -  that 
describes the use of tertiary n-butanol  for dehydration after 
staining and which helps keep the green staining green, not blue.

See also the latest edition of John Kiernan's most excellent book
ISB 0 7506 3106 6

Russ Allison, Wales