Richard and Histonetters,

We routinely stain canine skin lesions for Mast cells using the Quick 
Toluidine Blue Method as quoted in "Animal Tissue Techniques" by Gretchen 
L. Humason.  W H Freeman and Company 1972. This method uses 0.2% Toluidine 
Blue in 60% Ethanol.

Tissues are fixed in 4% Phosphate Buffered Formaldehyde and processed 
through ethanol and xylene. Sections are taken to ethanol and placed in Tol 
Blue for 1 - 2 minutes (longer doesn't make any difference)
We dehydrate quickly in ethanol, clear in xylene and mount in DPX.

Canine Mast Cell granules stain a purple-red colour and stick out like 
dog's..........

                         Regards,   Laurie.