Control of the Ferric Ion Concentration in Iron-Aceto-Carmine Staining

Abstract

The Fe+++ conc. is controlled by adjusting the FeCl3 normality of the iron-aceto-carmine staining solns. 2 stock mordant solns. are prepared by dissolving ferric chloride (FeCl3-6H2O; mol. wt. = 270.31) in 45% glacial acetic acid, the normality of one being [image]/1, and of the other [image]/10. By combining aceto-carmine (preferably prepd. from Merck''s carmine No. 40 N. F., or from the Coleman and Bell product) and one or the other of the stock mordant solns., a series of iron-aceto-carmine solns. is made up, each soln. being of a different normality for FeCl3, depending on the proportions combined. Trial series were [image]/50, [image]/100, [image]/500, [image]/1000 and [image]. Tissue (spermatogenic) from one specimen is fixed in Carnoy-2, divided equally among the 5 iron-aceto-carmine solns. for staining, then squashed, dehydrated and mounted as usual. Subsequently the trial series may be retained or adjusted. Advantages of the method: 1) discloses quickly the optimum stain for a particular tissue type; 2) automatically gives an optimum stain to cells in different maturational stages; 3) results are reproducible in subsequent operations. Tables and equations are provided for several other normalities and quantities of stain.