Methylene blue-fast green staining of hemopoietic colonies in agar cultures

A simple technique is described for the routine in situ identification of the cellular composition of colonies and clusters in agar cultures of hemopoietic cells. The entire culture, dried and formalin vapor fixed within a Petri dish, is stained with a mixture of methylene blue and fast green. By this method cellular ribonucleoproteins (RNP), deoxyribonucleoproteins (DNP) and some cationic (arginine and lysine containing) proteins are detected. Different maturation stages of neutrophils, eosinophils, basophils, monocytes, and macrophages can be easily identified with colonies and clusters on the basis of the cytoplasmic and nuclear staining.