A exact judgment of bone and bone marrow tissue is based on an undecalcified treatment technique by means of plastics embedding and hard section microtomy. All hitherto existing routine techniques of plastics embedding of bone tissue used monomeres of methakrylate with addition of so-called emollient substances for polymerisation. Disadvantages of a stronger shrinking of the polymerisation product and uncontrolled, not always avoidable accelerations of the polymerisation process which have an essentially negative influence on the histological results should thus be avoided. A very exact observance of the treatment steps is here necessary. In the further development of our embedding method we turned to the polymethacrylates. The polymerisation adhesive Kalloplast R used in industry proved as the most suitable initial substance for the new method. The yielded results lie in a considerable shortening and further simplification of the embedding technique. The results are always well reproducible. Undesirable shrinking or polymerisation artefacts with impairment of the histological results do no more appear.