Carbol Fuchsin as A Stain for Human Chromosomes

Cells derived from cultures of bone marrow or leucocytes were treated with hypotonic citrate solution, squashed in 45% acetic acid frozen with CO₂ to allow removal of the cover glass without disturbing the smear, and stained by the following schedule: absolute alcohol, 5 min; coat with 0.2% parlodion and air dry; 70% alcohol, 5 min; distilled water, 5 min; stain 2-5 min in a mixture of 45 ml of a 0.3% solution of basic fuchsin in 5% phenol, 6 ml of glacial acetic acid, and 6 ml of 37% formaldehyde. Differentiate and dehydrate in absolute alcohol, clear in xylene and cover. The stain is durable for several weeks if slides are stored in darkness when not in use. Results resemble those obtained by Feulgen or aceto-orcein methods.