Bone was prepared for scanning electron microscopy by sawing or fracturing into suitable pieces, most of which were extracted with hot 1, 2 ethane diamine to remove the organic matrix and cellular debris.

The identification of forming, resting and resorbing bone surfaces is discussed and the mineralizing front described.

Large and small Howship's lacunae were encountered. Resorption bays provided convenient sites for the study of collagen fibre orientation. Intimate resorption has not been detected.

The finding that collagen fibre bundles are only parallel over limited domains of “free” bone surfaces is discussed in the light of existing models of lamellar organisation. Randomly arranged, fine fibrillar collagen characterises all sites where cell movement is limited. It is concluded that freedom to move with respect to a forming surface is an essential factor if osteoblasts are to control the formation of oriented collagen.

The amorphous, mineralized, “interlamellar” and perilacunar ground substance is normally formed as a secondary process and is only found at the mineralizing front of “prolonged resting” surfaces;​ interlamellar bone is similar to peritubular dentine in being more resistant to resorption than the mineralized collagenous matrix that surrounds it.