Light microscopy of compact/adult unstained bone tissue seen by darkfield microscopy showing blood vessels filled with a red dye. The principal vessels pass through the central part of each osteon and are surrounded by concentric layers of osteocytes (white nuclei) and bone matrix. Vessels are interconnected by Volkmann?檚 vascular canals forming a rich vascular network. Magnification x 80 when printed at 10 cm.