Romanowsky-Type Staining: Effect of Adding Acid Dyes, Particularly Chromotrope 2R

Abstract

Nuclear staining can be depressed and nucleolar staining accentuated by the addition of 1 part of 1% chromotrope 2R to 9 parts of Gurr's Improved Giemsa R66; this mixture then being diluted -with an equal quantity of distilled water and allowed to stand for 0.5-1 hr before use. Methanol-fixed smears of Walker rat carcinoma, used as test material, were stained 5 min. Experiments with undiluted and diluted Giemsa indicate that ionisation of the azure-eosin complex is necessary for the development of the metachromatic red nuclear color of Romanowsky-type staining. It is suggested that chromotrope 2R depresses this ionisation.