1 % sulfuric acid alcohol for actinomycetes, nocardia. 0.5 -- 1 % sulfuric acid alcohol for oocysts of isospora, cyclospora. 0.25 -- 0.5 % sulfuric acid alcohol for bacterial endospores. Brucella differential stain -- glacial acetic acid used, no heat applied, secondary stain is loeffler 's methylene blue. Kinyoun modification (or cold Ziehl -- Neelsen technique) is also available. A protocol in which a detergent is substituted for the highly toxic phenol in the fuchsin staining solution.
what is the secondary stain in the acid fast stain
loeffler 's methylene blue