A Formalin-Wright Staining Technique for Avian Blood Cells

A rather concentrated alcoholic staining solution, an aqueous formalin-containing diluent, and a mixture of ethyl ether and absolute methyl alcohol are required. Formulas: A. Wright's stain (Harleco, Cert. No. LWr-52 was used), 3.3 gm; methyl alcohol, 500 ml. B. Formaldehyde solution 40% USP (Fisher's used), 0.25 ml; distilled water, 500 ml with its pH adjusted to 6.8 by addition of either 0.25% Na₂CO₂ or 0.25% HCl, as needed. C. A I:I mixture of ethyl ether and absolute methyl alcohol. Procedure: Prepare thin smears of normal or pathological avian blood, air dry, place the slides on a drying rack, cover with solution A, and let stand for about 8 min. Dilute the stain by dropping on a volume of B estimated to be equal to the volume of the partially evaporated stain, and let stand for 2-5 min, or until the surface is well covered by a metallic sheen. Wash with distilled water adjusted to pH 6.8 with the 0.25% Na₂CO₂ solution or 0.25% HCl. Dry the preparations quickly by blotting with filter paper. Differentiate and adjust the color intensities by dipping 6-10 times into C. Check the results microscopically and differentiate further if the colors are not properly balanced. Dry, uncovered preparations may be examined under oil; or, a cover glass can be applied with balsam or a synthetic resin for permanent mount. Results are similar to those described in textbooks, but have been more consistent than those obtained with other techniques for blood cells of chicken, pheasants, American and Indian partridge, quail, pigeon, turkey, goose, canary, and the Himalayan snow partridge.