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Although collagen of either tendon or dermis can be stained equally well with Ponceau 2R/Acid Fuchsin or Light Green SF if the dyes are used independently, tendon collagen retains the red dye mixture and dermal collagen the green counterstain when the dyes are used sequentially in the Masson trichrome procedure. The results of experiments designed to assess differences in the penetration, retention and displacement of these arylmethane dyes have demonstrated that they are retained more firmly by the tensioned collagen of tendon or stretched dermis, and are more easily displaced from the collagen of relaxed tendon or dermis.

Although normally, dermal collagen fails to retain the Ponceau 2R/Acid Fuchsin component of the Masson trichrome procedure and is stained green by the counterstain, the collagen of sections of human dermis which have been heated above its denaturation temperature (Ts) in moist conditions will retain the initial red stain. This difference in dye retention appears to be related to conformational changes of the collagen molecule which are associated with denaturation, for the change in staining is directly related to the shrinkage temperature, is reversed by rapid cooling after heating, is profoundly affected by differences in environmental conditions during heating which affect molecular rearrangement, and is age-dependent.

Several dyes, notably ponceau 2R, azofuchsin 3B, nitrazine yellow, and Biebrich scarlet may replace imported “ponceau de xylidin” in the Masson ponceau acid fuchsin mixture. Of these Biebrich scarlet appears to be the best and may be used without acid fuchsin.A mixture of equal parts of 5% solutions of phosphomolybdic and phosphotungstic acids is much superior to either acid alone and gives adequate mordanting in 1 minute at 22°C.With the fast green modification, times in plasma and fiber stains can be reduced to 2 minutes each. With anilin blue a 4-minute plasma stain is required. One-minute final differentiation in 1% acetic acid is adequate.Primary mordanting of formalin material may be accomplished by 5 minutes in saturated aqueous mercuric chloride or 2 minutes in saturated alcoholic picric acid. Three minutes washing in running water is required after these mordants.

The main constituents of wheat flour and many wheat flour products are wheat protein (gluten) and starch granules. The specific staining of the protein present was effected by 10 min in 0.1% aqueous ponceau 2R (C.I. No. 16150) acidified with 3—4 drops of 1 N H2SO4 per 50 ml of staining solution, followed by rinsing in 2 changes of distilled water, dehydrating, clearing and mounting in a resinous medium in the normal way. Staining of starch was as follows: sections or flour smears were brought to water, treated for 10 min in a protein-blocking reagent (Taninol ADR—Imperial Chemical Industries—used in 1% aqueous solution) rinsed, then stained for 3 mins in 0.5% aqueous chlorazol violet R (C.I. No. 32445) or for 10 min in either 0.5% aqueous chlorazol violet N (C.I. No. 22570), or chlorazol black E (C.I. No. 30235). Staining was followed by thorough rinsing, normal dehydration and clearing and mounting in a medium of R.I. about 1.49 to enhance visibility of unstained starch grains. The methods are applicable...

A SMALL drop of citrated human blood is placed on a slide next to a somewhat larger drop of Ponceau 2R and the two drops are mixed, covered with a cover glass and examined both with ordinary and polarized light. Under the double action of the dye and the hypotonicity, all the red cells become perfectly spherical with a diameter ranging from 5.0 to 5.6µ and stain weakly orange-red. No birefringence is observed.

Summary Calcium salts of acid dyes for lakes are widely used in the pigment industry, but these dyes have not yet been employed in the staining of calcium deposits. The usefulness of such dyes for light and fluorescence microscopy of calcium deposits was investigated. Human autopsy material was fixed in alcohol, Carnoy's fluid, methacarn, 10% unbuffered formalin or Zenker-formol. Deparaffinized sections were stained in 0.5% aqueous solutions of Biebrich Scarlet, Bordeaux Red B, Brilliant Black, Croceine Orange Y, Fast Light Rubine BL or Ponceau 2R for 30 minutes to one hour, rinsed in water, dehydrated and mounted. Alkali-soluble calcium deposits were stained intensely and selectively; alkali-insoluble calcium deposits remained unstained. Absolute alcohol, Carnoy's fluid and methacarn preserved calcium deposits equally well, but 10% unbuffered formalin and Zenker-formol removed alkali-soluble calcium deposits. Ponceau 2R imparted strong selective fluorescence to alkali-soluble calcium deposits. In mixed UV-blue plus green tungsten light calcium deposits were bright red; non-fluorescent tissue structures appeared green.

ONLY small amounts of alkaline phosphatase have hitherto been found in mammalian endocrines. It was, however, possible to demonstrate considerable quantities of this enzyme in the anterior pituitary lobe of both the male and the female guinea pig. After fixation of the glands in 96 per cent alcohol, in 80 per cent alcohol, in acetone or in pyridine-alcohol1, the Gomori technique2 was used. As already known, the nuclei of the anterior pituitary show a positive reaction which, however, has not been localized to any particular cell type3. In order to identify the type of cells containing the phosphatase, every two of four paraffin sections (thickness : 2–4μ) of each gland were examined as to content of phosphatase : the two other sections were stained by Masson‘s trichrome (acid fuchsin, Ponceau 2R and aniline blue) method.