Block Staining of Nervous Tissue with Silver IV. Embryos

Abstract
Procedures having enhanced reliability over older methods for both Bielschowsky and Cajal types of stain are described. Fixation of embryos in a solution containing 4% formaldehyde and 0.5% trichloracetic acid greatly improved the staining of neural elements by Bielschowsky's method. Among the variations of Cajal's type of staining tried, a modification of Ranson's pyridin-silver method gave the most complete staining of neurofibrillar elements. Washing for 0.5 to 1 hour after silver impregnation and shortening of the reduction time from 24 to 4 hours corrected the tendency of the method to overstain.