The Bielschowsky Staining Technic a Study of the Factors Influencing Its Specificity for Nerve FIBERS

Abstract

No specific means for inhibiting the staining of connective tissue and still permitting complete staining of nerve fibers was found. Over-staining could be corrected by reducing the concentration of the AgNO3 bath or by adding an excess of NH3 to the ammoniated silver bath. Staining of fine fibers was favored by adding acetic acid to the formaldehyde used for fixation or by adding pyridin to the AgNO3 bath. Addition of protein-precipitating organic acids (trichloracetic or sulphosalicylic) to the fixative was disadvantageous. Prolonged fixation favored an increase in intensity of the stain. Extraction of lipids with ammoniated alcohol gave results similar to those obtained after extraction with pyridine. Ammoniated silver carbonate without excess NH3 had an action similar to ammoniated silver hydroxide with excess NH3 of NH3 in the ammoniated Ag sol. (Ag H/10) was tolerated, without apparent impairment of nerve-fiber staining, up to 6 M NH3. Impregnation with 1.7% (N/10) AgNO3 sol. was quite satisfactory. Washing in 2.5% acetic acid between the ammoniated Ag bath and formaldehyde reduction was advantageous.