OBSERVATIONS ON THE EXTENDED USE OF THE MARCHI METHOD

Abstract

The spinal cords of 18 patients who had had a cordotomy a known interval before death were fixed for 10-14 days and spare blocks were stored for 15 to 72 months in formol-saline. For 10 weeks after a lesion the Marchi-positive material is mainly extracellular and stains very clearly after limited fixation but stains poorly after fixation for 2.5 years or longer. The Marchi-positive material is mainly intracellular by 12 months after the lesion and much of it stains clearly after limited and prolonged fixation. If the survival period is over 1 year vivid staining is obtained after prolonged fixation.