Abstract 1. 1. The historical development of tendon transplantation is briefly sketched. 2. 2. Traumatic and paralytic cases differ in that in the former the tendon sheath is destroyed. 3. 3. A method is described for creating a new tendon sheath by the use of celloidin. 4. 4. At a second operation the tendon may be transplanted into the newly formed sheath. Our thanks are due to the Dupont Company for furnishing us with the supply of chemically pure celloidin and for the cooperation of their staff, also to Miss Geraldine Kahn, whose aid in making the celloidin tubes was invaluable.