Block Staining of Nervous Tissue with Silver: III. Pericellular end-bulbs or boutons

Abstract

Fixation in 20 to 40% pyridin or in 10% chloral hydrate followed by 10 to 40% pyridin gave the most consistent staining of pericellular structures in the spinal cord of cat. Chloral hydrate perfusion and soaking followed by ammoniated alcohol (Hoff's application of Cajal's method) was uniformly successful only when pyrogallol instead of hydroquinone was used as a reducing agent. Perfusion of the animal with chloral hydrate gave a rather questionable degree of improvement over fixation by simple soaking. The difficulty in selecting a routine procedure as the “best” became apparent when no single experimental variation was outstandingly superior in all animals.