Preparation of fossil bone specimens for scanning electron microscopy.

A method is described for preparing fossil bone specimens for scanning electron microscopy. To obtain bone surfaces suitable for study, material was embedded in Epon 812 and selected faces exposed by grinding were subjected to controlled etching with a 4:1 mixture of 5% HNO3 and 1% OsO4. Surfaces thus prepared were further processed by the so-called clearing replicas technique. As a result of this procedure the bone surfaces revealed a network of anastomosing vascular canals the innter surface of whose walls could be examined in the scanning electron microscope. By etching extremely thin ground sections of bone stuck to plastic tape the contents of vascular canals as well as osteocytes can be isolated. This method ensures the good preservation of spatial relations between bone elements essential for studies of fossil bones, which are sometimes very brittle.