Sectioning Refractory Animal Tissues

Abstract

A method is described tor sectioning refractory material, particularly heavily yolked tissue. Fixation in a saturated picric acid-dioxan solution containing 10% formalin and 5% formic acid is recommended followed by dehydration in 2-ethoxyethanol. This greatly reduces pre-embedding hardening. Prior to clearing in three 4-hour changes of benzene, the tissue is placed for 12 hours in a bath of 2% celloidin in 2-ethoxyethanol. This impregnation prevents subsequent imbibition pressure from disrupting the anatomical relationships of the different parts. The material is embedded in wax and the block, trimmed to expose the tissue, is solvated for 12 hours in a 5% solution of Tergitol in pure ethane diol. This method has produced excellent sections and flaccid ribbons in a range of material which, prior to solvation, proved extremely refractory and, in some instances, impossible to cut.