[Use of the OTO-method in electron microscopic studies]

The modification of OTO-contrasting method (O-osmium, T-thiocarbohydrazide, O-osmium) allowing one to stain the structures of biological tissue in the process of its fixation is presented. The modification consists of an intermittent treatment of tissues with osmium tetroxide and thiocarbohydrazide after the tissue prefixation. This results in the formation of osmium-thiocarbohydrazide copolymer in form of "osmium black" and high tissue contrast corresponding to the true osmiophilia. The use of this modification permits one to give up an additional slide contrasting with a lead citrate and uranyl acetate.