The aim of the present study was to develop a porous, silastic tube with filmy wall acting as permanent artificial tendon. Twelve mongrel dogs were used. Peronaeus longus and Tibialis anticus were exposed respectively, divided in two places and sutured in situ. They were covered by the above-mentioned silastic tube. One dog each was sacrificed after 1, 2, 4, 6, 8, 10, 12, 16, 20 and 24 weeks, and 11 months; specimens were removed. Each preparation was studied as follows: gross observation and light microscopy for tendon preparation; transmission electron microscopy, scanning electron microscopy and phase microscopy for the pseudosheath. Our study showed that healing of tendon was mainly extrinsic mechanism and that the pseudosheath formed by silastic tube can prevent the adhesion of the surrounding tissue; therefore, use of the artificial tendon including a tendongraft coated with a silastic tube in reconstruction of flexor digital tendon in the hand is procedure feasible. But what the appropriate porous diameter and porous distance are, must be studied further. Tendon gliding mainly depends upon the gliding plane between the composite body of the tendon and the loose connective tissues around it.