Impregnation of Oligodendroglia in Nervous Tissue Kept in Formalin for Many Years

Abstract

This tissue is reconditioned by placing 12-30 [mu] frozen sections of it in concentrated ammonia (sp. gr. 0.9) and by washing them slowly for 24 hrs. with a 1 mm. stream of water. The fluid is then poured off the sections; the jar is refilled with concentrated ammonia; and washing is repeated for another 24 hrs. The sections are then plunged into concentrated ammonia for 7 min. After treatment in ammonia, the sections are incubated for one hour at 38[degree]C in Globus'' 5% HBr soln. They are washed again, in dist. water, and then impregnated in a "medium" strength ammoniacal silver carbonate soln. (5 ml. of 10% AgNO3 added to 15 ml. of 5% Na2CO3. The precipitate is dissolved in concentrated ammonia and diluted to 50 ml. with dist. water). Impregnation is followed by reduction in 1% formalin without agitation; fixation in 5% Na2S2O3; dehydration, and mounting in clarite.