Abstract
A method was used to demonstrate succinic dehydrogenase in tissue sections at 5[mu] with uni-form results by using the Linderstrom-Lang cryostat and iodo and nitro derivative of tetrazolium chloride. This new salt is much more rapid than other derivatives and gives a sharp color with a minimum of diffusion. The reaction was compared in tissues with alpha-glycerophosphate dehydrogenase (cytochrome), and alpha-glycerophosphate (DPN). Differences in localization in the kidney were demonstrated between succinic dehydrogenase and alpha-glycerophosphate dehydrogenase (cytochrome).