Abstract
Fresh-frozen sections of mouse ovary, briefly fixed in formalin, fail to stain with fuchsin-sulfurous acid (the Schiff reagent) or the Ashbel-Seligman carbonyl reagents. When the sections are treated for 10 minutes with mercuric chloride and then stained, the cytoplasm of the cells acquires a faint coloration—the plasmal reaction. When the sections are washed in water or dilute alcohol for 3 or 24 hours, however, lipid droplets become increasingly stainable. The results of treatment of the sections with halogens, oxidants and reductants suggest that the aldehydic substances which react with the Schiff reagent are all derived from unsaturated lipids but that, in addition, ketonic substances are formed or unmasked which are reactive to the hydrazide alone. Whether or not the ketonic lipids are steroidal has not been demonstrated.