Oil Blue N or Na as a Fat Stain for Animal Histology

Abstract

A stock saturated soln. of oil blue N or NA in 60% isopropanol, when diluted to 40 or 50% isopropanol, gives a precise dark blue staining of fatty substances in animal tissues in 5-10 mins., without appreciable precipitate. Suitable counterstains (e.g. Bismark brown R) in 1:1000 solutions require about 5 min. and should be followed by 1 min. differentiation in 5% acetic acid.