Volu-Sol's Bouin's Fixative Solution provides very good results with tissue that is subsequently stained using a trichrome procedure. This fixative preserves glycogen well but usually lyses erythrocytes. It is sometimes recommended for gastro-intestinal tract biopsies, animal embryos and endocrine gland tissue. Results show that it stains tissue bright yellow due to the presence of picric acid. Any excess picric should be washed from tissues prior to staining with 70% ethanol. Because of its acidic nature it will slowly remove small calcium deposits and iron deposits.