A method using the Spurr low-viscosity epoxy resin medium for the preparation of Von Kossa impregnated undecalcified bone sections for light microscopy is described. The method gives high quality thin sections (0.6-1.0 pm) of cancellous bone and overcomes some of the difficulties experienced with other plastics. The procedure is relatively simple and is well suited for use in a routine diagnostic laboratory.

VictoriaIn the recent paper on an improved technique for renal biopsies, Meadows and Schoemaker (1970) describe the use of a special wax to give fine sections at 1-2,.u. They illustrate their excellent results with Jones's silver technique. In this laboratory, however, difficulty was experienced with their use of ammoniacal ethanol and as we, in agreement with Eastham and Essex (1969), believe that the thinner sections possible with polymer-embedding are of greater diagnostic value, the present note describes the successful application of a methenamine-silver method on sections from Araldite. FixationBuffered formol saline is perfectly satisfactory and no differences in results have been observed with material fixed from six hours to two weeks.Attempts to impregnate the reticulin with Foot's method have not been satisfactory with epoxy-resin sections. The silver-methenamine method of Gomori and Grocott, already successfully used on acrylicresin sections, is now suggested as a simple way of demonstrating reticulin on epoxy-resin sections. A real advantage of epoxy resin (Araldite) is that thin sections (0-5,u) adhere to glass and this allows 'staining' on the slide and a flat, clean, mounted section. MethodsAfter fixation in formol saline, a portion of the renal biopsy, not longer than 5 mm, is selected for embedding in Araldite. The remainder of the needle

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